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   223054篇
  免费   4775篇
  国内免费   133篇
耳鼻咽喉   1508篇
儿科学   8694篇
妇产科学   4447篇
基础医学   22854篇
口腔科学   2018篇
临床医学   18956篇
内科学   39790篇
皮肤病学   1444篇
神经病学   21054篇
特种医学   9930篇
外国民族医学   38篇
外科学   33451篇
综合类   2825篇
一般理论   99篇
预防医学   24900篇
眼科学   3388篇
药学   11997篇
中国医学   710篇
肿瘤学   19859篇
  2024年   77篇
  2023年   507篇
  2022年   743篇
  2021年   1589篇
  2020年   954篇
  2019年   1505篇
  2018年   23384篇
  2017年   18394篇
  2016年   20616篇
  2015年   2274篇
  2014年   2714篇
  2013年   3561篇
  2012年   10895篇
  2011年   24864篇
  2010年   20783篇
  2009年   13307篇
  2008年   22741篇
  2007年   24892篇
  2006年   3598篇
  2005年   5160篇
  2004年   6080篇
  2003年   6770篇
  2002年   4772篇
  2001年   568篇
  2000年   600篇
  1999年   475篇
  1998年   668篇
  1997年   556篇
  1996年   387篇
  1995年   406篇
  1994年   352篇
  1993年   299篇
  1992年   176篇
  1991年   231篇
  1990年   244篇
  1989年   178篇
  1988年   163篇
  1987年   120篇
  1986年   129篇
  1985年   138篇
  1984年   147篇
  1983年   128篇
  1982年   152篇
  1981年   162篇
  1980年   148篇
  1979年   67篇
  1978年   67篇
  1976年   72篇
  1974年   77篇
  1938年   64篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
OBJECTIVES: CD62L was evaluated as a determinant of human pre-effector T cells. STUDY DESIGN AND SETTING: Phenotype and cytokine secretion profiles of CD62L cells were determined based on activation status. RESULTS: CD62L(Low) T cells demonstrated significantly higher secretion of interleukin (IL)-10 and interferon (IFN)-gamma than did CD62L(High) T cells. After activation, the majority of cells expressed high levels of the CD62L surface marker. Postactivation levels of IL-10 production remained elevated or unchanged. In a murine B16 melanoma model, freshly isolated CD62L(Low) tumor draining lymph nodes (TDLN) T cells showed increased secretion of IL-2 and IL-4 but not of IL-10 or IFN-gamma. The surface expression of CD62L and cytokine secretion patterns were maintained after activation with concomitant increases in IL-10. CONCLUSION: Our results provide evidence that CD62L(Low) T cells in TDLNs of progressively growing squamous cell carcinoma of the head and neck differ phenotypically and functionally from those of mouse origin. SIGNIFICANCE: Characterization of this human CD62L(Low) T cell population provides initial insight regarding novel surface markers in TDLN T cells that might correlate with antitumor reactivity.  相似文献   
82.
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors.  相似文献   
83.
84.
85.
86.
The specific characteristics of genetic data lead to ethical-legal conflicts in the framework of genetic diagnosis. Several international organisations, including UNESCO and the Council of Europe, have enacted rules referring to the use of genetic information. This paper discusses possible legal and ethical criteria that could be used in genetic testing.  相似文献   
87.
PURPOSE: To provide a model for assessing occupational therapy workforce needs by using a demand-based approach to determine current workforce status in the Northwest region. Regional information may have implications for addressing national occupational therapy service needs. METHOD: A questionnaire was sent to a proportional random sample of 234 facilities that hire occupational therapy practitioners. Data were collected in July-August 2003 using structured mailing and follow-up procedures. RESULTS: Response rate was 79%. Twenty-four percent reported occupational therapy vacancies and 11% occupational therapy assistant vacancies; 48% predicted an increase in occupational therapy positions in the next 2 years and 41% an increase in occupational therapy assistant positions. Sixty-three percent of respondents reported difficulty in hiring. DISCUSSION: This study identifies an occupational therapy workforce shortage in the Northwest. Management of a shortage is critical, for even short-term adjustments could lead to permanent changes in service provision. This study demonstrates the importance of current information on the status of the national workforce and serves as a model for future studies.  相似文献   
88.
89.
90.

Introduction  

This paper presents the results of a study on the psychometric properties of an authorized Spanish version of the McMaster Family Assessment Device, a self-report measure of family functioning.  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