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21.
Land and water resource issues typically fall under separate governance systems. For example, agricultural policy regulates land-cover change while water departments regulate water quality. However, land-use changes can directly affect water resources. Water flow regulation is a key service which is affected by changes in land-cover but its dynamics are poorly understood by most policy makers and land management organisations. We simulated and quantified the effects of plant invasions on land-cover, hydrological soil characteristics and catchment responsiveness on flow regulation using a hydrological model. The case study was located in the indigenous fynbos shrublands in South Africa. Fynbos requires fire to regenerate, has moderate biomass, occurs mostly in areas with a potential to erode and is prone to invasion by woody plant species, particularly trees. Invasions can affect flow regulation by changing community structure and function and increasing fuel loads. The greater fuel load increases fire intensity and severity which, in turn, changes the hydrological responses of catchments. Few studies have assessed the effects of invasion on hydrological responses but studies on plantations have recorded significant increases in soil water repellence following fire, resulting in increased overland flow similar to impacts of fires in invaded areas. Simulation of clear-felling of pines and different degrees of water repellency increased both the responsiveness of the catchment to rainfall and extreme rainfall events. The simulated fire effects were consistent with other studies of hydrological responses to fire. Our study indicates that invasions of pines and acacias in the study area could substantially increase the risk of flood damage even from moderate rainfall events, and highlights the importance of maintaining flow regulation capacity. New policy approaches are required which take account of the linkages and interactions between land-use choices, water resources and ecosystem services, and address them when considering governance arrangements.  相似文献   
22.
Studies from parts of Nigeria reported low compliance with seatbelt. This study sought to establish driver seatbelt use in Enugu, Nigeria by gender, vehicle type/use and time of day. Observations were done day and night at randomly selected locations. Data were analysed with SPSS version 15. Differences in response were checked with chi-square for trend. Confidence interval was 95% and P value < 0.05 was regarded as significant. Average compliance was 37.6% for the 510 males (85%) and 90 females (15%) observed. It was 74.8% in the day and 0.3% at night. Among males, 218 (42.7%) wore seatbelt while 9 (10%) females did. For commercial drivers 159 (65.2%) complied while 68 (19.1%) private drivers did. Truck drivers had 100% compliance while sports utility vehicle drivers had the lowest (18.8%). There is poor seatbelt compliance in Enugu, Nigeria and need for educational campaigns and stricter enforcement.  相似文献   
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The paper presents the findings of a research project aiming to quantify and subsequently classify several infrastructure-related road safety measures, based on the international experience attained through extensive and selected literature review and additionally on a full consultation process including questionnaire surveys addressed to experts and relevant workshops. Initially, a review of selected research reports was carried out and an exhaustive list of road safety infrastructure investments covering all types of infrastructure was compiled. Individual investments were classified according to the infrastructure investment area and the type of investment and were thereafter analysed on the basis of key safety components. These investments were subsequently ranked in relation to their safety effects and implementation costs and on the basis of this ranking, a set of five most promising investments was selected for an in-depth analysis. The results suggest that the overall cost effectiveness of a road safety infrastructure investment is not always in direct correlation with the safety effect and is recommended that cost–benefit ratios and safety effects are always examined in conjunction with each other in order to identify the optimum solution for a specific road safety problem in specific conditions and with specific objectives.  相似文献   
25.
The Valley of Flowers is a national park in the Himalayan state of Uttarakhand in India that was classified as a world natural heritage site in 1988. Around 1982, its maximum carrying capacity was fixed at 60 persons per day, which has been called excessive by experts and observers, given the extremely fragile and immensely valuable nature of the Valley's heritage. This, in monetary terms, can be put at millions of dollars, and is considerably more viewed in terms of knowledge of breeding medicinal plants in cold climates that are being affected by climate change, which its microclimate and ecology present. Given the state's poor resources and the fact that tourism is one of the most important industries for development and conservation, this research assesses the heritage value of the Valley and develops a programme for conservation, including a computerised program for permits, whose value can easily be raised from the current paltry Rs 150 per person. Accompanied by fallow periods and marketing through the Internet to aim for educated tourists, the program ensures that the maximum carrying capacity of the Valley is never exceeded, thus spreading out the number of tourists over its 3.5-month season, while allowing flexibility in booking for chance groups and small families that can pay more.  相似文献   
26.
李尚官 《价值工程》2012,31(36):120-121
近年来,公路经营企业发展对于我国收费公路快速发展起了非常重要的作用。本文对公路经营企业特点及面临困境进行了简要分析,并结合现代企业制度,给出了现代企业制度求解,这对于公路经营企业的进一步发展具有重要意义。  相似文献   
27.
目前,我国高速公路网络发展迅速,给人们带来交通便利的同时,也产生了许多问题。如何提高对高速公路各路段的综合管理水平,充分发挥路网中各高速公路之间快捷、畅通的通行优势,最大限度地降低人为干扰因素,已成为摆在高速公路管理者面前的一项新的研究课题。为此,尽快实现联网收费成为交通管理部门的重要工作目标之一。文章从工程应用的角度,对当前高速公路收费站应用无人值守自动发卡机工作流程的特点和通信过程中可能遇到的问题进行详细分析。  相似文献   
28.
浅析路桥施工过程产生的问题及其处理方案   总被引:1,自引:0,他引:1  
文章针对路桥施工过程产生的预应力技术问题、体外加固问题、防水层质量问题等几个典型问题及其处理方案进行了分析和探究。  相似文献   
29.
论路基路面施工质量通病及控制措施   总被引:5,自引:0,他引:5  
展峰 《价值工程》2011,30(12):88-88
公路工程质量问题成为一个焦点问题,为切实控制好路基分层施工,对填方路基必须按路面平行线分层控制填土标高;为切实控制路基压实度,必须按试验路路基填土厚度的90%控制规模施工时的填土厚度。  相似文献   
30.
刘翔  廖芳龄  朱棣 《价值工程》2011,30(20):86-87
城市道路的景观设计既是城市的特色也是交通安全的重要影响因素,本文通过介绍山水东路以及金石南路两条道路的景观设计,就城市道路的交通组成研究了对景观设计的要求,城市道路景观对交通的影响,提出了城市道路景观设计与交通协调的内容与方法。结果表明,城市道路的景观设计能调节道路使用者的心理状态,对改善交通状况、减少交通事故的发生有重要作用。  相似文献   
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