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1.
We analyze the effect of worker inflows on establishments’ productivity, using German data. Previous studies for other countries have found positive effects of hiring workers from superior (more productive or higher paying) firms. Ranking establishments by their median wage, we find that inflows from inferior establishments seem to increase hiring establishments’ productivity. Further empirical analyses suggest our findings are due to a positive selection of such inflows from their sending establishments. These workers might have to find a better job match in order to advance their careers, an interpretation supported by the finding that the effect is driven by workers with short tenure at their previous employer. Our findings reflect the increasingly assortative pattern of worker mobility in Germany found in a related strand of literature. 相似文献
2.
城市自生群落具有重要的生态服务功能与潜力,但因其外貌不被公众所接受而难以在城市公共空间中应用。将群落生态学和设计学相结合,探索一种介入栽培植物对城市自生群落进行改良,最终形成具有一定美学价值的植物群落的途径。实验以植物群落设计美学原理和种间竞争原理为依据,向已经演替1年的城市自生群落中引入63种栽培植物,按照分层的方式对群落进行改良。3年的观测结果表明,有61.9%的栽培植物可以在城市自生群落中定居并建立优势,能对76.7%的自生植物起到抑制作用,使55.8%的自生植物消失。相比城市自生群落,改良后的群落美观度提高29.4%,公众接受度提高24%,群落的物种丰富度提高至2.29倍。相比一般的人工植物群落,改良后的群落可以节约58.2%的建植成本,降低83.9%的浇水成本和67.8%的除草成本。实验证明改良设计是一种可行的群落设计途径,能有效提高群落的物种丰富度和美学价值,同时让自然参与群落设计过程,实现人与自然的合作。 相似文献
3.
赵亚杰 《中小企业管理与科技》2021,(9)
企业的经营生产离不开电力的供应,而现阶段我国的电力供应依靠发电厂供电,通过汽轮机等一系列机械设备来产生电能。就目前的情形来看,为了保证我国更好地发展,还需要加强对电力设备的保障,而汽轮机则是其中的重要环节。 相似文献
4.
作为兼具自然生命力与人工艺术魅力的遗产类型,历史园林保护与复建在全世界范围内受到关注。为全面了解历史园林复建研究的发展情况,对1983年以来国外历史园林复建文献进行系统综述,对历史园林复建的定义与内涵、历史园林面临的问题与挑战、复建的标准与依据、复建方法,以及复建效果5个主要研究领域进行了分析。基于历史园林遗产特征,从价值评判、活态特征、整体视角和动态变化4个方面探讨了历史园林复建原则,以期为中国历史园林传承发展提供借鉴。
关 键 词:风景园林;历史园林;系统综述;复建;遗产 相似文献
5.
文人园林营建过程中,园居植物的获取、选择、栽培以及品赏亦是一个较为复杂而必备的过程。江南常熟静圃(现名赵园)为晚清文人赵烈文所建。通过分析赵烈文撰写的《能静居日记》,并结合其他史料考证,在当时沿袭的文人审美标准下对同治四年至光绪十三年静圃中的植物应用过程及方式进行阐释,旨在获得关于晚清时期江南文人园林植物的历史性认识:静圃建园过程中植物主要通过苏州花肆购买、友人间赠送以及与种树人直接交易等方式获取;园中植物虽以地景、盆景区分,但种类选择与高濂、文震亨、李渔等给出的品赏范围并无明显差异;在定期维护的基础上,须保证后园可四时赏花,其中以春桃、夏荷、秋菊、冬梅为最,且植物的实用功能一直被延续。 相似文献
6.
:寺庙园林作为中国古典园林三大主流类型之一,历
史底蕴深厚,文化内涵丰富,具有重要的研究价值。与皇家
园林的气势恢宏、私家园林的精致细腻不同,基于佛教文化
背景产生的寺庙园林,有着独树一帜的造园特色。以宁波天
童寺为例,从整体布局、相地风水、植物配置、理景艺术等方
面对寺院的“匠心”布局进行分析,从视境、声境、嗅境、味
境和触境五境对寺庙园林造园“意境”进行阐述,总结寺庙园
林造园意匠特征,丰富传统园林文化理论,传承与弘扬我国传
统文化。 相似文献
7.
Absentee landowners, or those who do not live on their forestland, own approximately 117 million acres of private forestland in the U.S. Thus, their land management decisions and activities influence the flow of forest-based goods and services. We explore the question of whether absentee family forest owners are less active land managers than resident landowners and whether membership in conservation organizations is associated with higher levels of land management activity by absentee owners. To examine these questions, we administered a mail survey to randomly-selected family forest landowners in Indiana. While we found some support for the contention that absentee owners are less active forestland managers than resident owners, we also found they are not necessarily inactive landowners. We found absentee owners were less likely to have: inspected their forestland for invasive plants, pulled or cut invasive plants, used herbicides to kill invasive plants, reduced fire hazard, or grazed livestock than resident owners. Absentee owners were more likely to be enrolled in the Indiana Classified Forest and Wildlands Program, a preferential forest property tax program. Absentee owners who are members of a conservation organization were more likely than absentee non-member owners to have undertaken a variety of land management activities, including: undertaking wildlife habitat improvement projects, inspecting their forestland for invasive plants, pulling or cutting invasive plants, enrolling in the Indiana Classified Forest and Wildlands program, and obtaining a management plan. 相似文献
8.
以“PlanT”康复花园的场所设计及志愿者参与性活
动设计为疗愈方法,通过循证实验设计,采用中医体质量表评
价健康增益。研究结果表明:其花园参与性设计对志愿者有不
同的健康增益效果。26.67%的志愿者在参与活动后,曾由偏
颇体质转为平和体质,其中有16.67%转为平和体质并持续到
活动结束。活动结束时,在各体质的亚量表中,志愿者平和质
得分显著高于活动前,8种偏颇体质得分整体均有下降,其中5
种与活动前得分有极显著差异,2种有显著差异。调查问卷结果
表明:志愿者主观认为康复花园参与性设计对健康有明显增益
作用。选择9月采集中医体质量表数据,将实验组与对照组进行
对比,得到实验组转为平和质的人数较对照组高14%,实验组
中有2种体质在活动前后的亚量表分数有显著差异,对照组均无
显著差异。研究表明,康复花园参与性设计对本案例45~70岁
人群的健康增益有效。 相似文献
9.
Damiano Gianelle Alberto Romanzin Fabrizio Clementel Loris Vescovo Stefano Bovolenta 《国际农业可持续发展杂志》2018,16(1):64-73
The effect of different supplementary feeding rates for grazing cattle on high-altitude pastures dynamics was evaluated. A field experiment was carried out during three years in a subalpine pasture area of the Eastern Alps. The investigated pasture area was 40?ha, located between 1820 and 2230?m?a.s.l. Two paddocks were chosen in the experiment and two herds of 12 cattle each were kept in the two enclosures for 5 weeks. For the first herd (HS), the supplementary feeding rate was 4.8?kg?OM?head?1 per day, while for the second herd (LS), the rate was 1.6?kg?OM?head?1 per day. The amount of herbage consumed by each cattle was determined using the n-alkane technique. To monitor the pasture vegetation dynamics, eight metal exclusion cages were placed in each paddock to determine herbage growth, utilization rates, vegetation composition and animal grazing selectivity. Grazing behaviour of dairy cattle, in terms of herbage intake and species selection was affected by the different feeding rates. Cattle grazing Paddock HS consumed 1.9?kg?OM?day?1 of herbage less than Paddock LS. In the LS paddock, cattle grazed higher phytomass rates. When the animals were fed by higher concentrate rates, a more selective grazing seemed to significantly increase the pasture necromass component. The lower grazing selectivity favoured the development of species as Nardus stricta and Deschampsia caespitosa, which are well known for their low palatability. Distinct vegetation dynamic patterns were observed, with a reduction of hair grass and an increase of legumes in the Paddock LS. 相似文献
10.