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   1226篇
  免费   31篇
各国政治   86篇
工人农民   128篇
世界政治   95篇
外交国际关系   45篇
法律   583篇
中国政治   56篇
政治理论   257篇
综合类   7篇
  2023年   7篇
  2021年   14篇
  2020年   27篇
  2019年   33篇
  2018年   41篇
  2017年   34篇
  2016年   40篇
  2015年   29篇
  2014年   37篇
  2013年   188篇
  2012年   25篇
  2011年   36篇
  2010年   22篇
  2009年   35篇
  2008年   37篇
  2007年   39篇
  2006年   28篇
  2005年   22篇
  2004年   29篇
  2003年   28篇
  2002年   30篇
  2001年   24篇
  2000年   29篇
  1999年   17篇
  1998年   19篇
  1997年   14篇
  1996年   22篇
  1995年   20篇
  1994年   19篇
  1993年   13篇
  1992年   15篇
  1991年   16篇
  1990年   21篇
  1989年   18篇
  1988年   13篇
  1987年   16篇
  1986年   19篇
  1985年   21篇
  1984年   15篇
  1983年   16篇
  1982年   23篇
  1981年   9篇
  1980年   8篇
  1978年   9篇
  1977年   16篇
  1976年   13篇
  1975年   8篇
  1974年   6篇
  1973年   6篇
  1968年   6篇
排序方式: 共有1257条查询结果,搜索用时 15 毫秒
921.
The enzyme α-amylase has long been a commonly targeted protein in serological tests for saliva. While being especially abundant in saliva, α-amylase is detectable in vaginal secretions, sweat, fecal matter, breast milk and other matrices. As a result, assays for α-amylase only provide a presumptive indication of saliva. The availability of mass spectrometry-based tools for the detection of less abundant, but more specific, protein targets (e.g., human statherin) has enabled the development of high confidence assays for human saliva. Sample throughput, however, has traditionally been low due to multi-step workflows for protein extraction, quantitation, enzymatic digestion, solid phase cleanup, and nano-/capillary-based chromatography. Here, we present two novel “direct” single-stage extraction strategies for sample preparation. These feature immunoaffinity purification and reversed-phase solid-phase microextraction in conjunction with intact mass analysis of human statherin for saliva identification. Mass analysis was performed on the Thermo Scientific Q-Exactive™ Orbitrap mass spectrometer with a 10-min analytical run time. Data analysis was performed using Byos® from Protein Metrics. Two sample sets were analyzed with a population of 20 individuals to evaluate detection reliability. A series of casework-type samples were then assayed to evaluate performance in an authentic forensic context. Statherin was confidently identified in 92% and 71% of samples extracted using the immunoaffinity purification and solid phase microextraction approaches, respectively. Overall, immunoaffinity purification outperformed the solid phase microextraction, especially with complex mixtures. In toto, robotic extraction and intact mass spectrometry enable the reliable identification of trace human saliva in a variety of sample types.  相似文献   
922.
Analysts and researchers typically value knowledge for its contributions to the wisdom of policy action. Policymakers, however, typically value knowledge for its contributions to the exercise of political control. Our research on flows of knowledge among federal, state, and local education agencies documents how knowledge may increase the effectiveness of various control strategies. In these cases, knowledge is not intended to enhance rationality; it may or may not. It is intended to enhance control, and it does. Knowledge for control is particularly useful to policymakers who seek to intervene in policy arenas characterized by fragmented authority and widely dispersed resources.  相似文献   
923.
924.
Personality disorder symptoms were investigated in a community sample of young people (n = 714) to assess their relationship over time with well-being during adolescence and the emergence of intimacy in early adulthood. Drawing on Erikson's theory of psychosocial development, changes in adolescent well-being were conceptualized as indirect indicators of identity consolidation. Cluster B personality disorder symptoms (borderline, histrionic, and narcissistic symptoms) were conceptualized to represent identity diffusion—i.e. maladaptive personality traits that usually resolve during the identity crisis of adolescence. Latent growth models were used in 2 age cohorts to assess (1) interrelationships between Cluster B symptoms, well-being, and intimacy at mean ages 13.8 and 18.6 years; and (2) associations between their developmental trajectories over the next 6 years. As expected, higher personality disorder symptoms were associated with lower well-being during adolescence, and declines in personality disorder symptoms over time were associated with corresponding gains in well-being. Consistent with Erikson's developmental theory, there was an inverse relationship between Cluster B symptoms and intimacy that increased in strength as young people entered adulthood. As an indicator of successful identity consolidation, well-being was significantly associated with intimacy in female adolescents and young adults.  相似文献   
925.
Medical educators have begun to embrace service-learning as a method for teaching medical students to be more socially responsible, patient-oriented practitioners. However, research documenting the learning outcomes of service-learning in medical education is limited. In this paper, written documents generated through evaluation of a mandatory, structured community service-learning experience were analyzed qualitatively to discover the diverse learning outcomes among 24 students who participated in the experience. Preliminary findings indicate that students developed skills and attitudes directly related to competencies of concern in most U.S. medical programs. These preliminary findings may help other programs articulate learning outcomes for their service-learning programs. Further, these preliminary findings may stimulate more systematic research (qualitative and quantitative) in this area.  相似文献   
926.
927.
928.
929.
State governments have used several types of mandates to assure that local governments fulfill state-defined responsibilities, including public health care for the poor. This article reports the findings of a study of procedural public-participation mandates and financial sanctions imposed by California to hold counties to their obligations to provide indigent health care. An inventory of the laws' implementation in all California counties found noncompliance by some counties, although all counties complied after a state Health Services Department unit was established to monitor the counties and provide them with state aid. Case studies in eight counties identified factors that influenced the effectiveness of the laws in modifying or reversing county proposals to close county hospitals or reduce other health services. Policy guidelines are suggested for states that want to develop mandates to enforce indigent-care responsibilities of local governments.  相似文献   
930.
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