全文获取类型
收费全文 | 18067篇 |
免费 | 491篇 |
国内免费 | 2篇 |
专业分类
管理学 | 2546篇 |
民族学 | 96篇 |
人才学 | 4篇 |
人口学 | 1638篇 |
丛书文集 | 104篇 |
理论方法论 | 1756篇 |
综合类 | 501篇 |
社会学 | 8633篇 |
统计学 | 3282篇 |
出版年
2021年 | 101篇 |
2020年 | 243篇 |
2019年 | 371篇 |
2018年 | 419篇 |
2017年 | 602篇 |
2016年 | 451篇 |
2015年 | 339篇 |
2014年 | 419篇 |
2013年 | 3033篇 |
2012年 | 618篇 |
2011年 | 543篇 |
2010年 | 438篇 |
2009年 | 412篇 |
2008年 | 436篇 |
2007年 | 461篇 |
2006年 | 392篇 |
2005年 | 454篇 |
2004年 | 412篇 |
2003年 | 379篇 |
2002年 | 438篇 |
2001年 | 478篇 |
2000年 | 405篇 |
1999年 | 383篇 |
1998年 | 309篇 |
1997年 | 267篇 |
1996年 | 274篇 |
1995年 | 242篇 |
1994年 | 246篇 |
1993年 | 247篇 |
1992年 | 270篇 |
1991年 | 255篇 |
1990年 | 257篇 |
1989年 | 241篇 |
1988年 | 228篇 |
1987年 | 245篇 |
1986年 | 213篇 |
1985年 | 262篇 |
1984年 | 244篇 |
1983年 | 244篇 |
1982年 | 194篇 |
1981年 | 163篇 |
1980年 | 175篇 |
1979年 | 182篇 |
1978年 | 174篇 |
1977年 | 139篇 |
1976年 | 132篇 |
1975年 | 154篇 |
1974年 | 137篇 |
1973年 | 110篇 |
1972年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
781.
Ergonomics, usability and user-centered design are terms that are well known among designers. Yet, products often seem to fail to meet the users' needs, resulting in a gap between expected and experienced usability. To understand the possible causes of this gap the actions taken by the designer during the design process are studied in this paper. This can show whether and how certain actions influence the user-friendliness of the design products. The aim of this research was to understand whether ergonomic principles and methods are included in the design process, whether users are involved in this process and whether the experience of the designer (in ergonomics/user involvement) has an effect on the end product usability. In this study the design processes of 151 tangible products of students in design were analyzed. It showed that in 75% of the cases some ergonomic principles were applied. User involvement was performed in only 1/3 of the design cases. Hardly any correlation was found between the designers' experience in ergonomic principles and the way they applied it and no correlations were found between the designers' experience in user involvement and the users' involvement in the design process. 相似文献
782.
This paper presents the Ergonomic Work Analysis method in a Brazilian Dentist's office. Through the study, the constraints and the strategies in avoiding them were identified. It was found that dentists hardly use the position most indicated by the International Organization for Standardization (ISO) and the Federation Dentaire Internacionale (FDI) for both the patient and the dentist, which is respectively supine and 9 o'clock, due to the limited space and layout. Five types of treatments performed by the professional have been studied. The frequency and duration of actions in these treatments were accounted for and the standard positions adopted were identified. The AET was found to be a very suitable method to grasp the dentist's activity and build a point of view of the profession, which is characterized as: stressful, perfectionist and restrictive. Time management is presented as an important strategy to control the tension arising from performing the treatments. 相似文献
783.
The noise caused by the movement of users on their chairs in the work environment may indicate structural weaknesses and risk, and still significantly reduce productivity by increasing employees stress level. By understanding the activities to be developed in a work place one may understand what should be necessary to a good development, thereafter a search for improvement of labor activity with the aim of better use of resources in the operation of product use may be done. The analysis of the incremental variation of noise in professional chairs aims to identify its origin and the time the emission of noise starts during the period of use, its development and the major causative agents. Determining the characteristics of the sound of different materials and adjustments mechanisms of the chair can determine how different materials interact with each other. The measurement of these noises in an acoustic isolated room using directional microphones, if recorded and analyzed properly makes it possible to investigate and orientate to suspect elements in order to propose solutions and identify the quality of other similar chairs. Based on the results recommendations can be established for the orientation of users, managers and people responsible for the acquisition of the products, inducing them to review the employment of materials and the choice of the processes of production. These aspects are not covered in the Brazilian ergonomics norms and standards in the use of chairs. 相似文献
784.
Neeta S. Bijoor Heather R. McCarthy Dachun Zhang Diane E. Pataki 《Urban Ecosystems》2012,15(1):195-214
In semi-arid cities, urban trees are often irrigated, but may also utilize natural water sources such as groundwater. Consequently,
the sources of water for urban tree transpiration may be uncertain, complicating efforts to efficiently manage water resources.
We used a novel approach based on stable isotopes to determine tree water sources in the Los Angeles basin, where we hypothesized
that trees would rely on irrigation water in the soil rather than develop deep roots to tap into groundwater. We evaluated
the oxygen (δ18O) and hydrogen (δD) isotope ratios of xylem water, irrigation water, soil water, and groundwater in a study of temporal patterns
in water sources at two urban sites, and a study of spatial patterns at nine urban sites and one “natural” riparian forest.
Contrary to our hypothesis, we found that despite frequent irrigation, some trees tap into groundwater, although in most species
this was a small water source. Some trees appeared to be using very shallow soil water at <30 cm depth, suggesting that these
mature urban trees were quite shallowly rooted. In the natural site, trees appeared to be using urban runoff in addition to
shallow soil water. We were able to identify tree uptake of precipitation at only 3 sites. The results show that some irrigated
trees utilize groundwater and do not rely solely on irrigation water, which may make them able to withstand drought and/or
water conservation measures. However, some irrigated trees may develop very shallow root systems, which may make them more
susceptible. 相似文献
785.
786.
LAURENT C. GLIN ARTHUR P. J. MOL PETER OOSTERVEER SIMPLICE D. VODOUHÊ 《全球网;跨国事务杂志》2012,12(3):333-354
In this article, we attempt to conceptualize the historical development and the governance structure of the transnational organic cotton network from Benin. We aim to discover how the organic cotton production‐consumption network is governed locally and internationally. Existing bodies of literature on international agricultural production networks, in particular the Global Value Chains (GVC) perspective, focus on economic dimensions, but find it difficult to incorporate the sustainability dimension. We favour widening the concept of GVCs beyond economics by acknowledging and including environmental rationalities and the representatives of their interests, not as external elements, but rather as co‐governing or co‐structuring factors (or actors) of sustainable value chains. Our findings reveal that beyond the traditional producer versus buyer dualism, intermediate stakeholders, namely transnational and local environmental NGO networks, are instrumental in the construction, maintenance and transformation of the organic cotton network. It is also apparent that farmers' leaders play an important role in mediating and (re)building trust among organic farmers, though they exert insufficient vertical power in the organic cotton network to control it. 相似文献
787.
788.
Onda Kyle Sinha Parmanand Gaughan Andrea E. Stevens Forrest R. Kaza Nikhil 《Population and environment》2019,41(2):126-150
Population and Environment - The measurement and characterization of urbanization crucially depends upon defining what counts as urban. The government of India estimates that only 31% of the... 相似文献
789.
Pinchoff Jessie Shamsudduha Mohammad Hossain Sharif Mohammed Ismail Shohag Abdullah Al Mahmud Warren Charlotte E. 《Population and environment》2019,41(2):235-251
Population and Environment - This analysis examines whether salinity in drinking water is associated with pre-eclampsia and eclampsia (PE/E), a leading cause of maternal morbidity and mortality.... 相似文献
790.
Social Indicators Research - In this paper, we aim at ranking a set of nursing homes based on their ability in maintaining their residents’ physical conditions as good as possible. In this... 相似文献