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   1553篇
  免费   49篇
管理学   204篇
民族学   12篇
人才学   1篇
人口学   110篇
丛书文集   4篇
理论方法论   200篇
综合类   12篇
社会学   817篇
统计学   242篇
  2023年   11篇
  2022年   5篇
  2021年   15篇
  2020年   40篇
  2019年   53篇
  2018年   44篇
  2017年   87篇
  2016年   48篇
  2015年   45篇
  2014年   45篇
  2013年   267篇
  2012年   53篇
  2011年   50篇
  2010年   53篇
  2009年   48篇
  2008年   74篇
  2007年   52篇
  2006年   53篇
  2005年   36篇
  2004年   40篇
  2003年   37篇
  2002年   45篇
  2001年   32篇
  2000年   40篇
  1999年   30篇
  1998年   27篇
  1997年   19篇
  1996年   22篇
  1995年   17篇
  1994年   24篇
  1993年   15篇
  1992年   19篇
  1991年   13篇
  1990年   9篇
  1989年   11篇
  1988年   7篇
  1987年   4篇
  1986年   16篇
  1985年   20篇
  1984年   7篇
  1983年   11篇
  1982年   4篇
  1981年   8篇
  1980年   7篇
  1978年   4篇
  1977年   4篇
  1976年   8篇
  1975年   7篇
  1974年   3篇
  1967年   4篇
排序方式: 共有1602条查询结果,搜索用时 10 毫秒
91.
论文在讨论四个移民典型案例的基础上 ,讨论在项目中与政策相关的教训  相似文献   
92.
This paper presents a method of estimating a receiver operating characteristic (ROC) curve when the underlying diagnostic variable X is continuous and fully observed. The new method is based on modelling the probability of response given X , rather than the distribution of X given response. The method offers advantages in modelling flexibility and computational simplicity. The resulting ROC curve estimates are semi-parametric and can, in principle, take an infinite variety of shapes. Moreover, model selection can be based on standard methods within the binomial regression framework. Statistical accuracy of the curve estimate is provided by a simply implemented bootstrap approach.  相似文献   
93.
美国和加拿大对于学区在教育变革中的作用研究已有近40年的历史.关于学区在教育变革中的作用研究可划分为几个具有不同特点的时期,包括创新实施时期、高效学校范式时期、学校重构时期和基于标准的变革时期.综述列举了不同研究时期最重要的一些研究,并讨论了它们的研究特点和成果.在关于成功学区的案例研究的基础上,着重分析了学区在系统改进学生学习的过程中所面临的挑战、学区改进学生学习所采取的策略以及学区影响教学和学习质量的证据.同时,总结并讨论了12条促进学生学习的学区策略,提供了5个关于学区在教育变革中的作用的研究方向.  相似文献   
94.
Infants follow the gaze of an individual with whom they are directly interacting by the end of the first year. By 18 months infants are capable of learning novel words in observational (or third‐party) contexts (Floor & Akhtar, 2006). To examine third‐party gaze following in 12‐ and 18‐month‐olds, the parent and experimenter engaged in a conversation while the infant was present. For 8 trials approximately every 30 sec the experimenter would turn her head to the right or left to fixate on a toy placed on either side of the room with the parent following suit. In the first experiment, the parent was seated next to the infant and the experimenter opposite, whereas in the second experiment the positions of the adults were switched. In Experiment 1, 18‐month‐olds but not 12‐month‐olds followed gaze. In Experiment 2, 12‐month‐olds acquired a tendency to follow gaze during the experimental session. These results suggest that an incipient ability to follow third‐party gaze is present by 12 months and that infants acquire a more reliable and general ability to follow the gaze of noninteractive others between 12 and 18 months.  相似文献   
95.
Quantitative Approaches in Use to Assess Cancer Risk   总被引:4,自引:0,他引:4  
  相似文献   
96.
97.
A pre-defined list of family therapy intervention strategies was used to predict post-therapy perceived life happiness and marital happiness among husbands and wives. Clients presented with both child and marriage-focused problems. The data were analyzed separately for husbands and wives. In general, favorable outcome for husbands was associated with active restructuring operations on the part of the therapist. Prediction of outcome for wives was less clear. However, wives did appear to respond favorably to less active interventions such as actualizing transactional patterns and reframing.  相似文献   
98.
In the last 15 years, a substantial number of studies have tested the theoretical validity of Bowen family systems theory. A review of this basic research provided empirical support for the relationship between differentiation and chronic anxiety, marital satisfaction, and psychological distress. Bowen's assumption that couples with the same level of differentiation marry was not supported. His specific theories of sibling position and triangulation also received little empirical support. Research on multigenerational transmission has generally ignored Bowen's theoretical perspective, and more research needs to test Bowen's claim that his theory is universal. In addition, researchers still need to examine the effect of differentiation on child functioning, physical health problems, and adaptability.  相似文献   
99.
This research is based on in-depth ethnographic interviews and focus groups with 88 African American family caregivers from various regions of the United States during a stressful time in their family development--caregiving at the end-of-life--and the grieving during the aftermath. The study employed a stratified purposeful sampling strategy. Subjects were African Americans from the Northern, Southern, and Midwestern United States. Formal care is complicated by the distrust that many African Americans hold toward the health care system, which has resulted from years of exclusion, racism and discrimination. The findings highlight the importance of hearing from African American families to gain an understanding of what services, including family therapy and other psychotherapy, they will need during this process.  相似文献   
100.
An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m3 inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10?4, 3.6 × 10?4, and 2.2 × 10?6 per μg particulate organics per m3 air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m3 for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10?4 to 0.60 × 10?4; that for the heavy-duty diesel engine was 0.02 × 10?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.  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