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121.
[目的]研究全球气候变化背景下气候生产潜力的时空分布特征,对于合理利用农业气候资源,促进农业生产力的提高具有重要意义。[方法]选择1901—2000年哈萨克斯坦24个代表气象站点的月平均气温和降水资料,采用Thortwaite Memorial、Miami模型估算气候生产潜力,并运用气候倾向率、M-K检验以及ArcGIS空间插值等方法对气候生产潜力时空分布特征进行分析。[结果](1)1901—2000年哈萨克斯坦气候生产潜力总体表现为增长趋势,不同时段气候生产潜力差异明显,相对于其他研究时段(T1,T3),T2(1936—1970年)时段气候生产潜力及增长速率最大,并且水热匹配状况最好;(2)哈萨克斯坦气候生产潜力空间分布地域性明显。YP(降水生产潜力)和Y E(蒸散生产潜力)总体表现为自东南向西北递减的趋势,YT(气温生产潜力)表现为自西南向东北递减的趋势,气候生产潜力高值区主要位于天山北麓及东部山区的河谷地带,低值区位于西部和南部荒漠区;(3)气候生产潜力对降水更为敏感,当气温保持不变,降水量增加(减少)10%、20%,YE将增加(减少)9.6%、19.94%。[结论]哈萨克斯坦东部气候生产潜力大于西部,天山北麓及河谷地区气候生产潜力大于平原地区,哈萨克斯坦气候生产潜力主要受降水量的制约,未来“暖干型”变化将会使研究区气候生产潜力下降。为提高农业生产潜力,必须加强对农业基础设施的建设和提高水资源的调配能力。  相似文献   
122.
In recent years, numerous articles have addressed management strategies aimed at assisting forests to adapt to climate change. However, these seldom take into account the practical and economic implications of implementing these strategies, notably, supply of forest plants and seed. Using semi-structured interviews with practitioners involved in the plant and seed supply chain in Great Britain, we highlight a series of practical and economic bottlenecks commonly encountered in the supply of locally sourced seed and domestically produced planting stock for native woodland and hedging markets. We find that adoption of alternative seed sourcing strategies, designed specifically to account for directional climate warming, is likely to exacerbate existing problems by adding further complexity to decisions nurseries make about tree species and seed origins to produce. The lack of long-term market predictability brought about by the current configuration of forestry grants and regulations and, in particular, the administrative systems for processing grant applications is identified as a major impediment to having a sustainable and competitive supply of home-grown and currently adapted planting stock. Finally, the time and effort it takes to supply healthy plants for native woodland creation projects deserves much wider recognition throughout the industry and will be crucial if planting objectives are to be met sustainably.  相似文献   
123.
Shortfalls in global food production, coupled with the growing visibility of climate change's disruptive effects, have underlined for many observers the importance of devoting rural lands to their ‘optimal’ use, where they can make maximal contributions to the global imperatives of feeding the human population and maintaining vital environmental services. In this context observers have endorsed rural land use planning as a way to insure that, at least in theory, lands get devoted to their best uses. In practice, land use planning in the developing world has resembled ‘organized anarchy’. Small landholders with insecure land tenure, overseas investors seeking large land deals, NGOs representing indigenous peoples, government officials, and staff from international environmental NGOs and multilateral organizations have come together in strategic action fields to struggle over and sometimes negotiate land use plans for contested landscapes. These plans represent a strategic, spatially explicit response to the climate change–biodiversity–food security crisis.  相似文献   
124.
面对气候变化的机遇与挑战,中国政府已采取了一系列积极的政策和切实的行动,其中包括将于2017年启动全国性碳交易体系。研究首先对碳交易体系的国外研究作了简要概述,然后梳理了以欧盟碳交易体系为首的10个国外碳交易体系和中国7个省市的碳交易试点的实践。研究最后对全国碳交易体系的建立提出了几点思考,强调了数据的科学监测和林业碳汇在中国碳交易体系中的重要作用。  相似文献   
125.
The conservation and management of protected areas in urban settings has become increasingly challenging with dynamics over land use change in adjacent urban areas being highly relevant to, but at times conflicting with, the protected area. This study seeks to better understand the implications of land use change processes to urban protected area management through the case study of the Las Piñas – Parañaque Critical Habitat and Ecotourism Area (LPPCHEA) in Metro Manila, Philippines. Factors and processes influencing land use change and protected area management and the impact of stakeholders’ perceptions on protected area were analyzed. The urban protected area in itself has limited influence on its surrounding urban areas, as land use change in these areas is shaped more by social, economic and policy/institutional factors occurring within the context of urban-regional development. The study also found that land use conflict is evident in an urban protected area due to the competing ecosystem services derived by various stakeholders. This discord is deepened by the lack of coordination between land use planning and protected area management. Integrating protected area management with land use planning through legally binding instruments, specific timeframes and clear internal procedures can help resolve land use conflict for an urban protected area at the strategic or policy level.  相似文献   
126.
Research summary> : W e take a microfoundational approach to understanding the origin of heterogeneity in firms' capacity to adapt to technological change. We develop a computational model of individual‐level learning in an organizational setting characterized by interdependence and ambiguity. The model leads to organizational outcomes with the canonical properties of routines: constancy, efficacy, and organizational memory. At the same time, the process generating these outcomes also produces heterogeneity in firms' adaptive capacity to different types of technological change. An implication is that exploration policy in the formative period of routine development can influence a firm's capacity to adapt to change in maturity. This points to a host of strategic trade‐offs, not only between performance and adaptive capacity, but also between adaptive capacities to different forms of change . Managerial summary : W hy are firms differentially effective at adapting to technological change? We argue that firms differ in the adaptive capacity of the routines that underlie their capabilities. These differences arise well before change occurs, and result because firms build routines that are differentially responsive to signals of performance decline associated with technological change. Thus, early managerial efforts to build superior productive efficiency must be complemented by efforts to build superior adaptive capacity. Our theory suggests that managers can prepare for technological change by implementing policies, in the formative period of organizational development, that promote individuals' exploration of novel actions. However, there are trade‐offs because preparation aimed at building adaptive capacity to one type of technological change may limit adaptive capacity to other types of change . Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
127.
128.
This paper investigates the relationship between environmental regulations and innovation by focusing on the automobile industry in a cross-country setting. We provide empirical evidence that the presence of agency problems mitigates the negative effects of environmental regulations on overall R&D activity, which leads to full compensation when the degree of agency problems is sufficiently high. Guiding our empirical analysis, we provide a general model consistent with the structure of existing ownership data. Specifically, we model ownership structure as a combination of two extreme corporate governance types. On the one extreme there are profit maximizers, and on the other extreme there are managers who are only concerned with their private benefits. The model leads to a simple country level ownership indicator and shows that if an economy is dominated by firms with higher agency problems, then pollution tax might even increase overall R&D, while reducing pollution. According to our estimations, such an outcome is possible only for out-of-sample values of the ownership indicator, where the degree of agency problems is extremely high.  相似文献   
129.
Land use change is strongly modifying the traditional landscape of hilly productive Mediterranean sites. An example of these circumstances is the Langhe region (Piemonte, NW Italy), where woody plantations such as vineyards and orchards have been cultivated on hillslopes for centuries. In this paper we assess landscape changes occurred in the Diano study area (2651 ha) in the 1954–2000 period and we ascertain land use transition paths and rates of this rural ecosystem. Land use mapping obtained from object-oriented analysis of aerial photographs was used to quantify land use changes between 1954 and 2000. To examine the spatio-temporal patterns of land use change over time, a set of spatial statistics capturing different dimensions of landscape change was identified. An increase of landscape heterogeneity from 1954 to the present was observed due to the expansion of orchards and the fragmentation of field crops. A significant portion (55%) of current orchards surface is represented by former field crops, 24% by vineyards and 15% by forests. The strong expansion of hazelnut orchards concurred to the fragmentation of traditional rural landscape was dominated by vineyards, field crops and forests. Hazelnut orchards expansion was mainly located in places where grapes cultivation was less remunerative. A further expansion of hazelnut in the area should be planned, discussed and carefully monitored through change detection studies in order to avoid potential unsustainable use of the land.  相似文献   
130.
Recent non-parametric statistical analysis of high-frequency VIX data (Todorov and Tauchen, 2011) reveals that VIX dynamics is a pure jump semimartingale with infinite jump activity and infinite variation. To our best knowledge, existing models in the literature for pricing and hedging VIX derivatives do not have these features. This paper fills this gap by developing a novel class of parsimonious pure jump models with such features for VIX based on the additive time change technique proposed in Li et al., 2016a, Li et al., 2016b. We time change the 3/2 diffusion by a class of additive subordinators with infinite activity, yielding pure jump Markov semimartingales with infinite activity and infinite variation. These processes have time and state dependent jumps that are mean reverting and are able to capture stylized features of VIX. Our models take the initial term structure of VIX futures as input and are analytically tractable for pricing VIX futures and European options via eigenfunction expansions. Through calibration exercises, we show that our model is able to achieve excellent fit for the VIX implied volatility surface which typically exhibits very steep skews. Comparison to two other models in terms of calibration reveals that our model performs better both in-sample and out-of-sample. We explain the ability of our model to fit the volatility surface by evaluating the matching of moments implied from market VIX option prices. To hedge VIX options, we develop a dynamic strategy which minimizes instantaneous jump risk at each rebalancing time while controlling transaction cost. Its effectiveness is demonstrated through a simulation study on hedging Bermudan style VIX options.  相似文献   
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