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   13337篇
  免费   198篇
  国内免费   1篇
管理学   1812篇
民族学   44篇
人才学   6篇
人口学   1204篇
丛书文集   47篇
理论方法论   1142篇
综合类   192篇
社会学   6017篇
统计学   3072篇
  2023年   78篇
  2020年   181篇
  2019年   272篇
  2018年   278篇
  2017年   429篇
  2016年   278篇
  2015年   230篇
  2014年   275篇
  2013年   2387篇
  2012年   425篇
  2011年   338篇
  2010年   288篇
  2009年   255篇
  2008年   336篇
  2007年   343篇
  2006年   293篇
  2005年   270篇
  2004年   249篇
  2003年   211篇
  2002年   254篇
  2001年   307篇
  2000年   264篇
  1999年   264篇
  1998年   225篇
  1997年   221篇
  1996年   196篇
  1995年   185篇
  1994年   172篇
  1993年   197篇
  1992年   221篇
  1991年   192篇
  1990年   211篇
  1989年   184篇
  1988年   194篇
  1987年   189篇
  1986年   171篇
  1985年   166篇
  1984年   176篇
  1983年   162篇
  1982年   158篇
  1981年   122篇
  1980年   140篇
  1979年   176篇
  1978年   132篇
  1977年   130篇
  1976年   128篇
  1975年   139篇
  1974年   101篇
  1973年   89篇
  1972年   80篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
This paper describes the application of a model to design and manage the manufacturing process through an integrated system, using a Hierarchical methodology-by means of different aggregation and disaggregation stages with an appropriate time horizon. The hierarchical model obtained allows interfacing between the master schedule and the schedule of the orders. At each level of the hierarchical model some decisions have to be made in order to design the manufacturing system, but having a model that also takes into consideration the management of the system. To do this it is necessary to use aggregated information concerned with the level at which decisions are made. It is obtained from the database, which contains the information at the highest level of aggregation. This model has been applied to a metal mechanic company, that makes final products such as car washers, etc. The benefits of this approach for the company are addressed in this paper.  相似文献   
862.
One of the basic functions of an MRP system is to issue rescheduling messages that urge the planner tospeed up or slow down open orders. It seems in practice that these messages are not used at all by planners. This is mostly due to the inaccuracy of MRP, that more or less ignores safety time, safety stocks and lotsize flexibility in the calculation of reschedule-in messages. Reschedule-out messages are usually ignored because planners do not see the value of the message. Other reasons for not adhering to rescheduling messages are a lack of maintenance of MRP parameters or simply the wrong use of the MRP function. In the future, MRP rescheduling functionality will be used even less than today, due to the changing role of MRP within the planning framework. With the uprise of finite capacity scheduling packages, MRP is being pushed one level upward in the planning hierarchy. This means that rescheduling functionalities for the short term will become completely obsolete in MRP systems.  相似文献   
863.
Today's manufacturing enterprises face tremendous competitive pressures. Global competition, together with market demands for customized products delivered just in time, place tremendous pressures on manufacturers. The emerging global economy is rapidly replacing local markets. The emergence of open markets, reductions in trade barriers, and improvements in transportation and communications links have led to a situation where local competition and markets operate in the context of global standards. This open infrastructure allows manufacturers to respond to these challenges by working more closely with their suppliers and customers, and by building extended enterprises across the whole value chain. Such extended enterprises present great challenges in terms of redesigning business processes to create a competitive advantage from the linkages they include. This paper describes the manufacturing philosophies currently in vogue. Any manufacturing or related business will need to use them, albeit tailored to its own circumstances, in one form or the other, to ensure its prosperity.  相似文献   
864.

Violence against psychiatric staff seems to be on the increase. Such abuse can lead to mental health consequences for the staff and a reluctance to be closely involved with patients. Few Swedish investigations have examined violence against mental nurses and psychiatrists, or undertaken comparative studies between them. In this study we examined the extent, nature and determinants (i.e. risk factors) of violence against psychiatric nurses (n = 731) and psychiatrists (n = 320) working in the eight health care districts of Stockholm. These caregivers were assessed cross-sectionally by means of a questionnaire covering various areas (e.g. violence and work environment). The majority of the participants (85%) reported having been exposed to violence during their careers, with 57% being victimized in the past 12 months. Physical violence was common, and factors such as negative attitudes to work and diminished sense of autonomy were associated with an increased vulnerability to violence. Nurses and psychiatrists did not differ in violence variables. In spite of the weaknesses of the design (cross-sectional self-selecting sample), this study corroborates previous findings and identifies personal factors associated with violence that have received little attention in the literature (e.g. lack of respect for the organization of care).  相似文献   
865.

In recent years, the Australian university sector has undergone large-scale organizational change, including restructuring, downsizing and government funding cuts. At the same time, research from across the globe reports an alarming increase in the occupational stress experienced by university staff. We report on the first phase of a longitudinal investigation of occupational stress. A total of 22 focus groups were conducted with a representative sample of 178 academic and general staff from 15 Australian universities. The groups focused on understanding staff 's experience of occupational stress, and perceptions of the sources, consequences and moderators of stress. Both general and academic staff reported a dramatic increase in stress during the previous 5 years. As a group, academic staff reported higher levels of stress than general staff. Five major sources of stress were identified including: insufficient funding and resources; work overload; poor management practice; job insecurity; and insufficient recognition and reward. The majority of groups reported that job-related stress was having a deleterious impact on their professional work and personal welfare. Aspects of the work environment (support from co-workers and management, recognition and achievement, high morale, flexible working conditions), and personal coping strategies (stress management techniques, work/ non-work balance, tight role boundaries and lowering standards), were reported to help staff cope with stress. The findings provide a timely insight into the experience of stress within universities.  相似文献   
866.
Major natural disasters in recent years have had high human and economic costs, and triggered record high postdisaster relief from governments and international donors. Given the current economic situation worldwide, selecting the most effective disaster risk reduction (DRR) measures is critical. This is especially the case for low‐ and middle‐income countries, which have suffered disproportionally more economic and human losses from disasters. This article discusses a methodology that makes use of advanced probabilistic catastrophe models to estimate benefits of DRR measures. We apply such newly developed models to generate estimates for hurricane risk on residential structures on the island of St. Lucia, and earthquake risk on residential structures in Istanbul, Turkey, as two illustrative case studies. The costs and economic benefits for selected risk reduction measures are estimated taking account of hazard, exposure, and vulnerability. We conclude by emphasizing the advantages and challenges of catastrophe model‐based cost‐benefit analyses for DRR in developing countries.  相似文献   
867.
Risk assessments are crucial for identifying and mitigating impacts from biological invasions. The Fish Invasiveness Scoring Kit (FISK) is a risk identification (screening) tool for freshwater fishes consisting of two subject areas: biogeography/history and biology/ecology. According to the outcomes, species can be classified under particular risk categories. The aim of this study was to apply FISK to the Iberian Peninsula, a Mediterranean climate region highly important for freshwater fish conservation due to a high level of endemism. In total, 89 fish species were assessed by three independent assessors. Results from receiver operating characteristic analysis showed that FISK can discriminate reliably between noninvasive and invasive fishes for Iberia, with a threshold of 20.25, similar to those obtained in several regions around the world. Based on mean scores, no species was categorized as “low risk,” 50 species as “medium risk,” 17 as “moderately high risk,” 11 as “high risk,” and 11 as “very high risk.” The highest scoring species was goldfish Carassius auratus. Mean certainty in response was above the category “mostly certain,” ranging from tinfoil barb Barbonymus schwanenfeldii with the lowest certainty to eastern mosquitofish Gambusia holbrooki with the highest level. Pair‐wise comparison showed significant differences between one assessor and the other two on mean certainty, with these two assessors showing a high coincidence rate for the species categorization. Overall, the results suggest that FISK is a useful and viable tool for assessing risks posed by non‐native fish in the Iberian Peninsula and contributes to a “watch list” in this region.  相似文献   
868.
869.
870.
A case study on the implementation of a just-in-time (JIT) production system by a Canadian manufacturer in the heavy machinery industry is presented. Many hurdles and difficulties were encountered during implementation and the way in which these problems were resolved is reported. While the successful implementation of a JIT system depends on a host of technical and human factors, this study suggests that the people involvement factor is the most crucial. It is seen that the key elements to securing people involvement are institution leadership, company-wide education and training and mutual understanding, trust and respect among employees. The moral of this study is that without employee involvement nothing will happen and no result will be achieved.  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