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   11579篇
  免费   677篇
  国内免费   39篇
耳鼻咽喉   147篇
儿科学   301篇
妇产科学   267篇
基础医学   1494篇
口腔科学   349篇
临床医学   1046篇
内科学   2101篇
皮肤病学   92篇
神经病学   1398篇
特种医学   265篇
外科学   1314篇
综合类   149篇
一般理论   27篇
预防医学   1191篇
眼科学   331篇
药学   919篇
中国医学   28篇
肿瘤学   876篇
  2022年   42篇
  2021年   134篇
  2020年   77篇
  2019年   153篇
  2018年   204篇
  2017年   150篇
  2016年   165篇
  2015年   180篇
  2014年   289篇
  2013年   487篇
  2012年   677篇
  2011年   746篇
  2010年   410篇
  2009年   399篇
  2008年   788篇
  2007年   837篇
  2006年   802篇
  2005年   876篇
  2004年   846篇
  2003年   851篇
  2002年   832篇
  2001年   95篇
  2000年   55篇
  1999年   101篇
  1998年   153篇
  1997年   143篇
  1996年   133篇
  1995年   109篇
  1994年   94篇
  1993年   109篇
  1992年   77篇
  1991年   64篇
  1990年   55篇
  1989年   55篇
  1988年   56篇
  1987年   39篇
  1986年   49篇
  1985年   65篇
  1984年   117篇
  1983年   79篇
  1982年   110篇
  1981年   119篇
  1980年   88篇
  1979年   51篇
  1978年   51篇
  1977年   45篇
  1976年   39篇
  1975年   38篇
  1974年   39篇
  1973年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
OBJECTIVE: The objective of this study was to determine if temporomandibular joint (TMJ) samples positive for Chlamydia trachomatis have a greater presence of tumor necrosis factor-alpha (TNFalpha) or interleukin-6 (IL-6) when compared with Chlamydia-negative samples. STUDY DESIGN: Posterior bilaminar tissue samples removed during TMJ surgery from 70 patients were evaluated. Cryosections were stained using monoclonal antibody that identifies C. trachomatis. The presence of IL-6 and TNFalpha were evaluated by immunostaining in 15 samples positive and in 25 samples negative for the presence of C. trachomatis. RESULTS: Of the 70 TMJ samples, 32 (46%) were positive for C. trachomatis. In 15 samples positive for C. trachomatis, 10 (67%) were positive for TNFalpha and 7 (47%) for IL-6. In 25 samples negative for C. trachomatis, only 4 (16%) were positive for TNFalpha and only 2 (8%) for IL-6. Differences in C. trachomatis-positive samples versus negative were significant for both TNFalpha (P < .002) and IL-6 (P < .008). CONCLUSION: The presence of C. trachomatis in the TMJ is associated with a significantly increased presence of TNFalpha and IL-6.  相似文献   
12.
13.
14.
15.
The identification of clinically relevant, active immunomodulatory agents is important for developing immunotherapeutic approaches to chronic lymphocytic leukemia (CLL) and other B-cell lymphomas that are not curable with conventional chemotherapy. In this investigation, the imidazoquinoline Toll-like receptor (TLR)-7/8 agonist, imiquimod, was found to mediate the clearance of a lymphomatous skin lesion in a CLL patient. Imidazoquinolines also activated TLR-7/8 signaling pathways, resulting in increased expression of costimulatory molecules on circulating tumor cells. These observations extend the therapeutic spectrum of imiquimod to cutaneous B-cell lymphomas and suggest the use of TLR-7/8 agonists in CLL immunotherapy.  相似文献   
16.
Volumes of medial and lateral temporal lobe structures were assessed using magnetic resonance imaging (MRI) in 11 patients with late-life onset schizophrenia (LOS), 18 normal elderly controls and 12 patients with moderate cognitive impairment due to Alzheimer's disease (AD) who had no non-cognitive symptoms. While both patient groups has smaller volumes of several medial temporal regions (e.g. entorhinal cortex, left hippocampus), schizophrenics had significantly smaller anterior superior temporal gyri (STG) than normal controls, but AD patients did not. We have previously demonstrated anterior STG volume to be reduced in early life onset schizophrenia.  相似文献   
17.
18.
 The behavioral effects of GBR 12909, a selective dopamine uptake inhibitor, were determined in squirrel monkeys trained to respond under a fixed-interval (FI) schedule of stimulus termination and a second-order schedule of IV drug self-administration. Intermediate doses of GBR 12909 increased FI response rate markedly, and the highest dose decreased response rate below control values. The 5HT uptake inhibitors, alaproclate and fluoxetine, and the 5HT agonist, quipazine, attenuated the behavioral-stimulant effects of GBR 12909, whereas the 5HT2A/2C antagonist, ritanserin, enhanced the behavioral-stimulant effects of the lowest dose. GBR 12909 reliably maintained self-administration, and ritanserin increased response rate maintained by the highest dose. The dopamine agonist, quinpirole, increased FI response rate in only one of three subjects, and ritanserin enhanced the behavioral-stimulant effects of quinpirole in that subject. The dopamine agonist, apomorphine, only decreased FI response rate, and ritanserin did not alter its behavioral effects. The pharmacological profile of GBR 12909 administered alone and in combination with selective 5HT drugs in the present study was similar to that obtained previously with cocaine, further demonstrating that 5HT can reliably modulate the behavioral effects of psychomotor stimulants with prominent dopaminergic actions. Received: 9 July 1996 / Final version: 22 November 1996  相似文献   
19.
The Child and Adolescent Trial for Cardiovascular Health (CATCH) is a multisite intervention research study that builds on significant progress made in school health education research in the 1980s. The study has three phases: Phase I deals with study design, intervention, and measurement development, Phase II involves the main trial in 96 schools in four states, and Phase III focuses on analysis. The intervention program targets third-fifth grade students and focuses on multiple cardiovascular health behaviors, including eating habits, physical activity, and cigarette smoking. Classroom curricula, school environmental change, and family involvement programs are developed for each grade level and behavioral focus. This paper describes Phase II of CATCH with a rationale for cardiovascular health promotion with youth. The process of change that appears to be necessary for school-based health promotion and that will be tested in CATCH are presented as a framework to guide these efforts.  相似文献   
20.
This paper was originally developed by Calu Lester, the founder of KWICFAN, which took a novel approach to grass roots AIDS education in the black community. Calu died of AIDS before completing the work and the paper was completed by Larry L. Saxxon, who was both a friend of Calu's and an AIDS program consultant.

The paper presents a critical perspective of black America's response to the AIDS epidemic. The findings are frightening. Denial within the black community, coupled with a lack of support from the agencies responsible for funding AIDS education, has created a potential epidemiological nightmare. IV drug use continues to be a critical problem of frightening magnitude, allowing an efficient vehicle of HIV transmission. Most sadly of all, the social conditions that create and perpetuate the problematic drug abuse patterns still continue in black America. Black people are clearly becoming the new face of AIDS.  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