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   1899篇
  免费   92篇
  国内免费   2篇
耳鼻咽喉   39篇
儿科学   84篇
妇产科学   49篇
基础医学   267篇
口腔科学   37篇
临床医学   215篇
内科学   353篇
皮肤病学   24篇
神经病学   161篇
特种医学   97篇
外科学   171篇
综合类   24篇
一般理论   2篇
预防医学   105篇
眼科学   16篇
药学   128篇
中国医学   6篇
肿瘤学   215篇
  2022年   13篇
  2021年   25篇
  2020年   15篇
  2019年   24篇
  2018年   20篇
  2017年   18篇
  2016年   15篇
  2015年   17篇
  2014年   19篇
  2013年   68篇
  2012年   120篇
  2011年   114篇
  2010年   56篇
  2009年   57篇
  2008年   108篇
  2007年   113篇
  2006年   130篇
  2005年   106篇
  2004年   98篇
  2003年   105篇
  2002年   85篇
  2001年   53篇
  2000年   38篇
  1999年   25篇
  1998年   16篇
  1997年   23篇
  1996年   16篇
  1995年   17篇
  1994年   16篇
  1993年   15篇
  1992年   32篇
  1991年   43篇
  1990年   35篇
  1989年   25篇
  1988年   20篇
  1987年   33篇
  1986年   21篇
  1985年   25篇
  1984年   16篇
  1983年   18篇
  1982年   11篇
  1980年   9篇
  1979年   21篇
  1978年   9篇
  1977年   11篇
  1974年   12篇
  1973年   10篇
  1972年   8篇
  1970年   11篇
  1967年   10篇
排序方式: 共有1993条查询结果,搜索用时 109 毫秒
1.
Development of the Practical Solutions for Pesticide Safety guide used participatory research strategies to identify and evaluate solutions that reduce pesticide exposures for workers and their families and to disseminate these solutions. Project principles were (1) workplace chemicals belong in the workplace, and (2) pesticide handlers and farm managers are experts, with direct knowledge of production practices. The project’s participatory methods were grounded in self-determination theory. Practical solutions were identified and evaluated based on five criteria: practicality, adaptability, health and safety, novelty, and regulatory compliance. Research activities that had more personal contact provided better outcomes. The Expert Working Group, composed of farm managers and pesticide handlers, was key to the identification of solutions, as were farm site visits. Audience participation, hands-on testing, and orchard field trials were particularly effective in the evaluation of potential solutions. Small work groups in a Regional Advisory Committee provided the best direction and guidance for a “user-friendly” translational document that provided evidence-based practical solutions. The “farmer to farmer” format of the guide was endorsed by both the Expert Working Group and the Regional Advisory Committee. Managers and pesticide handlers wanted to share their solutions in order to “help others stay safe,” and they appreciated attribution in the guide. The guide is now being used in educational programs across the region. The fundamental concept that farmers and farmworkers are innovators and experts in agricultural production was affirmed by this study. The success of this process demonstrates the value of participatory industrial hygiene in agriculture.  相似文献   
2.
Ninety-seven inpatients with tardive dyskinesia (average AIMS score = 13), the majority of whom were schizophrenic, were studied. Forty patients were Caucasian, and 57 were African-American. The APOE genotypes of these patients were compared to previously published genotypes of controls and with previously published studies of APOE genotypes in patients with schizophrenia. There were no significant differences in APOE allele frequencies comparing the African-American tardive dyskinesia population and the African-American control groups. In contrast, significant (< 0.05) P values were obtained comparing the Caucasian tardive dyskinesia population to the Caucasian controls, when comparing allele frequencies and genotypic frequencies. This study suggests that Caucasians bearing an APOE2 allele are at increased risk of developing tardive dyskinesia, whereas African-Americans are not. APOE genotype-specific risks of both tardive dyskinesia and Alzheimer's disease that vary across populations could be due to recruitment of patients or controls or could be due to modifying effects of differing genetic or environmental backgrounds. The mechanism by which the APOE2 allele increases risk of tardive dyskinesia is not known. Further information about the mechanisms of increased risk of tardive dyskinesia could result in stratification of prescribing practices weighing the costs of medications against the relative risk of side effects.  相似文献   
3.
Study Objective . To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-β-hydroxycortisokcortisol ratio. Design . Prospective study. Subjects . Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity. Interventions . Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. Measurements and Main Results . Mean weekly 6-β-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. Conclusion . Cytochrome P450 3A4 activity as measured by 6-β-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.  相似文献   
4.
5.
6.
7.
8.
The search for the ideal bone substitute began hundreds of years ago, and continues today. While numerous choices have been proposed and tested, with varying degrees of success, there remain many challenges related to the use of bone substitutes in craniofacial reconstruction. This paper presents a review of the history of bone substitute research, a discussion of currently popular materials, and elucidation of the challenges to be faced as we approach the new millennium.  相似文献   
9.

Background  

Resident-led morning report is an integral part of most residency programs and is ranked among the most valuable of educational experiences. The objectives of this study were to evaluate the effect of a resident-as-teacher educational intervention on the educational and teaching experience of morning report.  相似文献   
10.
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