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   1635篇
  免费   73篇
  国内免费   22篇
管理学   72篇
劳动科学   1篇
民族学   33篇
人口学   16篇
丛书文集   309篇
理论方法论   76篇
综合类   1032篇
社会学   92篇
统计学   99篇
  2024年   1篇
  2023年   15篇
  2022年   22篇
  2021年   31篇
  2020年   22篇
  2019年   23篇
  2018年   32篇
  2017年   35篇
  2016年   31篇
  2015年   42篇
  2014年   67篇
  2013年   88篇
  2012年   80篇
  2011年   103篇
  2010年   95篇
  2009年   106篇
  2008年   115篇
  2007年   99篇
  2006年   116篇
  2005年   72篇
  2004年   69篇
  2003年   82篇
  2002年   147篇
  2001年   115篇
  2000年   58篇
  1999年   19篇
  1998年   8篇
  1997年   7篇
  1996年   6篇
  1995年   1篇
  1994年   7篇
  1993年   2篇
  1992年   2篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
  1972年   1篇
  1969年   1篇
排序方式: 共有1730条查询结果,搜索用时 15 毫秒
101.
瑞典的《医疗生物银行法》在实施过程中出现适用范围有限、伦理原则缺失、有关职责界定不清等问题,科学界和医疗界提议出台新的生物银行法以替代旧法,促进医疗领域健康发展。瑞典新的生物银行法报告在尊重个体完整和隐私的前提下,将监管所有人类组织样本的收集、存储和使用,并将完善样本捐献者的知情同意,强化样本捐献者的自决权,增加可追溯性规定和样本库个人资料处理原则,申明生物样本跨界合作的安全问题,对正在修订《涉及人的生物医学研究伦理审查办法》的我国具有借鉴意义。  相似文献   
102.
农地流转是促进农地规模经营的必经之路,已成为新一轮农地制度改革的中心议题。基于江苏、广西、湖北及黑龙江四省区农户调查数据的实证分析结果显示,交易费用是影响农地流转的一个重要约束因素,农地流转中存在的交易费用既抑制转入户转入土地,又抑制转出户转出土地。因此,新一轮农地制度改革进程中应全面降低农地流转面临的各类交易费用,促进农地经营权规范有序流转,发展农业适度规模经营。  相似文献   
103.
104.
This study examined the trajectory of problem behaviours in domestically adopted children in South Korea as they aged. This study used the Panel Study on Korean Adopted Children's longitudinal, three‐wave data (2006, 2008 and 2010). Although data were collected at three time points, our data consisted of six time points, which covered the 5–10 years age range of the adopted children at the time of survey. One hundred sixty‐four children were included in the analysis, 75 of whom contributed to one time point, 74 to two time points and 15 to three time points. The trajectory of the problem behaviours of adopted children was examined using a piecewise hierarchical linear growth model. Because the initial exploration of the data suggested non‐linear changes in behaviour problems over time, we split the growth trajectory into two time periods: Time 1 (5–7 years) and Time 2 (7–10 years). A two‐rate model was used to estimate separate slopes for the two time periods. Results showed that the externalizing and internalizing problems of adopted children have different trajectories. Internalizing problems did not show significant changes after 5 years of age, while externalizing problems increased until 7 years of age and decreased significantly thereafter.  相似文献   
105.
We consider the online (over time) scheduling on a single unbounded parallel-batch machine with job processing time compatibilities to minimize makespan. In the problem, a constant \(\alpha >0\) is given in advance. Each job \(J_{j}\) has a normal processing time \(p_j\). Two jobs \(J_i\) and \(J_j\) are compatible if \(\max \{p_i, p_j\} \le (1+\alpha )\cdot \min \{p_i, p_j\}\). In the problem, mutually compatible jobs can form a batch being processed on the machine. The processing time of a batch is equal to the maximum normal processing time of the jobs in this batch. For this problem, we provide an optimal online algorithm with a competitive ratio of \(1+\beta _\alpha \), where \(\beta _\alpha \) is the positive root of the equation \((1+\alpha )x^{2}+\alpha x=1+\alpha \).  相似文献   
106.

Industrialized areas represent a special group of urbanized areas, but sufficient attention has not been given to them concerning plant species richness and its importance for biodiversity conservation. These sites are considered the main drivers of biological invasions and biotic homogenization on a global scale, but the question of how and to what degree they contribute to biodiversity has yet to be raised. Data for 62 river ports (16 German, 26 Czech, 7 Hungarian, 4 Slovak, and 9 Austrian) on two important Central European waterways (the Elbe-Vltava and Danube waterways) were gathered for 40 years. In total, 1 240 plant species were found. Of these, 371 were classified as threatened and protected, nearly one third of the total number of species found in all of the studied Elbe, Vltava, and Danube ports. Significant differences in the proportion of threatened species in ports and cities were not found. More threatened species were found in the Danube ports than in the other ports, but their numbers fluctuated depending on the size of the port and the region (country). The results showed that the ports must be regarded as special types of species-rich industrial areas; thus, they should not be considered to be only sources of spreading invasive alien species. When planning port development, uniformity and vegetation management that is too intensive should be avoided. Extensively managed open areas and habitat diversity should be maintained.

  相似文献   
107.
This study draws on social comparison theory and the spread activation literature to explore the effects of opinions about the personal traits of Chinese and Americans on the United States (US) public’s perceptions of the Sino–US relationship. The study also explores how perceptions of the Sino–US relationship predict the perceived importance of various Chinese policy issues. The analyses of the secondary survey data showed that comparisons of positive and negative traits had different effects on public opinion about the Sino–US relationship. The respondents who viewed China as a partner or as a competitor also thought that human rights, the freedom of Tibet, and economic issues were important. Those who viewed China as an enemy believed that the selling of arms to Taiwan was important. The implications of the findings for theory construction and national image campaigns are discussed.  相似文献   
108.
齐骥 《学术探索》2012,(2):95-103
对十年来中国文产业理论与实践发展历程的全面梳理,是在我国文化产业发展进入一个崭新的历史发展阶段进行的。这一研究以2002年党的十六大召开,提出发展文化产业的基本任务,指明文化产业发展的基本方向为起点,把自2002年到2011年党的十七届六中全会提出建设社会主义文化强国十年历史进程中,文化产业概念研究、发展战略研究、文化体制改革研究、文化产业发展实务研究以及文化产业学术载体、档案和里程碑事件研究作为研究对象,系统梳理十年间文化产业的理论脉络、研究重点和研究方向。  相似文献   
109.
2010年广州亚运会旅游的战略地位与应对策略   总被引:3,自引:0,他引:3  
广州亚运会具有体育与事件旅游双重属性。旅游业是深度利用亚运会的主力资源,是提升城市竞争力的动力产业,在亚运会战略实施中占有重要地位,因此应在亚运赛前、赛中与赛后采取相应对策。政府的高度重视与战略规划是实施关键。  相似文献   
110.
以某综合体育馆吊装施工为例,建立了吊装施工信息模型系统,分析了BIM技术在吊装领域的应用.该模型以CAD三维模型为基础,利用ANSYS和3D3S进行有限元力学分析,完成了吊装过程初步分析和吊点选择,并生成了分析结果数据文档.根据施工现场情况确定吊机停靠位置,生成了吊机站位布置图.通过CAD三维模型和内力分析结果完成吊机、吊具的选取,并获得吊装施工示意图.该实例探讨了空间结构吊装施工的建筑信息模型实践应用,对空间结构的施工信息化建设起到推动作用.  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