首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   19921篇
  免费   491篇
  国内免费   1篇
管理学   2640篇
民族学   80篇
人才学   1篇
人口学   1717篇
丛书文集   108篇
教育普及   2篇
理论方法论   1802篇
综合类   458篇
社会学   9645篇
统计学   3960篇
  2020年   295篇
  2019年   376篇
  2018年   396篇
  2017年   609篇
  2016年   443篇
  2015年   373篇
  2014年   420篇
  2013年   3426篇
  2012年   614篇
  2011年   502篇
  2010年   380篇
  2009年   382篇
  2008年   462篇
  2007年   484篇
  2006年   389篇
  2005年   495篇
  2004年   421篇
  2003年   382篇
  2002年   401篇
  2001年   475篇
  2000年   432篇
  1999年   436篇
  1998年   322篇
  1997年   314篇
  1996年   327篇
  1995年   287篇
  1994年   275篇
  1993年   298篇
  1992年   358篇
  1991年   336篇
  1990年   321篇
  1989年   313篇
  1988年   290篇
  1987年   284篇
  1986年   275篇
  1985年   251篇
  1984年   306篇
  1983年   293篇
  1982年   250篇
  1981年   191篇
  1980年   220篇
  1979年   262篇
  1978年   198篇
  1977年   188篇
  1976年   167篇
  1975年   179篇
  1974年   159篇
  1973年   141篇
  1972年   114篇
  1971年   103篇
排序方式: 共有10000条查询结果,搜索用时 399 毫秒
971.
This paper presents a multivariate method to assess the comprehension of safety signs. The proposed method uses the MDS and Procrustes, to obtain a consensus perceptual map. The results show that the map allowed discriminating signs with high levels of comprehension from others. The safety signs have no statistical difference as depicted by Bootstrap Analysis.  相似文献   
972.
This study aimed to perform an ergonomic analysis in a fiberglass parts factory. For this purpose, was used the methodology of Ergonomic Work Analysis (EWA). At the end of the study it was possible to identify some ways to the development of improvements in order to contribute to the transformation of working conditions in the sector analyzed.  相似文献   
973.
Packaging and labeling play a crucial role awhile protecting medicaments and transmitting a range of crucial information to the users. Taking into account the scarcity of specific studies in this area, it was considered great the need for a comprehensive survey about customers' satisfaction when handling these containers.  相似文献   
974.
975.
The main focus of risk management is technical and rational analysis about the operational risks and by those imposed by the occupational environment. In this work one seeks to contribute to the risk perception study and to better comprehend how a group of occupational safety students assesses a set of activities and environmental agents. In this way it was used theory sustained by psychometric paradigm and multivariate analysis tools, mainly multidimensional scaling, generalized Procrustes analysis and facets theory, in order to construct the perceptual map of occupational risks. The results obtained showed that the essential characteristics of risks, which were initially splited in 4 facets were detected and maintained in the perceptual map. It was not possible to reveal the cognitive structure of the group, because the variability of the students was too high. Differences among the risks analyzed could not be detected as well in the perceptual map of the group.  相似文献   
976.
A number of studies to better understand the complex physiological mechanism involved in regulating body weight have been conducted. More specifically, the hormones related to appetite, leptin and ghrelin, and their association to obesity have been a focus of investigation. Circadian patterns of these hormones are a new target of research. The behaviour of these hormones in individuals subject to atypical working times such as shiftwork remains unclear. Shiftwork is characterized by changes in biological rhythms and cumulative circadian phase changes, being associated with high rates of obesity and metabolic syndrome. Truck drivers, who work irregular shifts, frequently present a high prevalence of obesity, which might be associated with work-related factors and/or lifestyle. In this context, the aim of this paper was to discuss the relationship of body mass index, appetite-related hormones and sleep characteristics in truck drivers who work irregular shifts compared with day workers.  相似文献   
977.
A scenario of an automotive accident caused by tire failure is given followed by a human factors analysis of the information available to consumers on tire aging. Consumers have not been told that the age of the tire is a safety concern. It is not easy to decode the date of manufacture on tires. More publicity and prominent warnings are needed to communicate the dangers of older tires. Also, better ways to present the date of manufacture so that consumers can more easily and accurately assess tire age are needed.  相似文献   
978.
Virtual reality is the use of interactive replication created with computer hardware and software to impart users with opportunities to engage in environments that appear to feel similar to real world objects and events. The commonest rehabilitation program of cerebral palsy children involves stretching, strengthening, mobilization and various other activities, whereas the use of virtual reality based training (VRBT) for rehabilitation of cerebral palsy is not common. To understand the effect of VRBT a study was formulated. Twenty nine subjects participated (study group--14 and control group--15). Outcome measures were MACS, PBS, level of participation, motivation, cooperation and satisfaction of the child. Results revealed that balance and manual ability were significantly improved in both the groups (Balance: study: t-2.28, p<0.05; control: t-3.5, p<0.01; Manual ability: study: t-5.58, p<0.001; control: t-7.06, p<0.001). PBS had significantly greater improvement in the study group (t-t-2.02, p<0.05). Level of participation, motivation, cooperation and satisfaction of the child were also reported to be significantly higher among the study group as compared with control group. To the author's best knowledge, this is the first study on using the VR-based therapy for the postoperative rehabilitation of children with CP which need further elaboration with larger sample size.  相似文献   
979.
Pieper R 《Work (Reading, Mass.)》2012,41(Z1):3321-3324
Work equipment and installations with a high risk for health and safety of employees should be paid a special attention. The German Product Safety Act, which is aimed to manufacturers or distributors in order to protect consumers, maintains a conclusive catalogue of these so-called "installations in need of monitoring" fixing the work equipment and installations for which such special inspections can be demanded. This catalogue has remained unchanged for decades and has been transformed nearly unmodified into the Plant Safety Ordinance. Currently, there is a discussion about this catalogue in Germany. A major point of concern is the definition and the significance of "especially" dangerous work equipment and installations. Two recent research projects are dealing with the problem how to define "especially".  相似文献   
980.
Motmans R 《Work (Reading, Mass.)》2012,41(Z1):2476-2481
Forklift drivers in warehouses are often exposed to whole body vibration (WBV) during the total day. There is however an association between working as a forklift operator and the development of low back pain. In this study the exposure to WBV was measured in five forklift drivers who performed a standardised order picking task during 10 minutes. The effect of driving surface (uneven concrete vs. new flat concrete), driving speed (15 km/h vs. 8 km/h) and seat suspension (mechanical suspension vs. air suspension) was investigated. Improving the driving surface was the most effective preventive measure by reducing the whole body vibration with 39%, from 1.14 to 0.69 m/s2. Lowering the speed limit resulted in a reduction of WBV with 26% (1.05 vs. 0.78 m/s2). An air suspension seat was 22% more effective compared to mechanical suspension (1.02 vs. 0.80 m/s2). On uneven concrete an air suspension seat performed even better by reducing the WBV by 29% (1.33 vs. 0.95 m/s2). A combination of a new driving surface, limiting the maximum speed and the introduction of an air suspension seat reduced the whole body vibrations below the action limit of 0.5 m/s2 as mentioned in the European directive. None of the interventions were effective enough on their own.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号