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   7822篇
  免费   653篇
  国内免费   20篇
耳鼻咽喉   64篇
儿科学   295篇
妇产科学   166篇
基础医学   944篇
口腔科学   114篇
临床医学   1089篇
内科学   1589篇
皮肤病学   63篇
神经病学   784篇
特种医学   209篇
外科学   1162篇
综合类   139篇
一般理论   2篇
预防医学   831篇
眼科学   153篇
药学   513篇
中国医学   18篇
肿瘤学   360篇
  2023年   47篇
  2022年   66篇
  2021年   166篇
  2020年   121篇
  2019年   181篇
  2018年   183篇
  2017年   144篇
  2016年   162篇
  2015年   168篇
  2014年   236篇
  2013年   360篇
  2012年   561篇
  2011年   587篇
  2010年   283篇
  2009年   249篇
  2008年   444篇
  2007年   493篇
  2006年   492篇
  2005年   484篇
  2004年   479篇
  2003年   406篇
  2002年   335篇
  2001年   132篇
  2000年   115篇
  1999年   131篇
  1998年   83篇
  1997年   71篇
  1996年   44篇
  1995年   48篇
  1994年   55篇
  1993年   49篇
  1992年   64篇
  1991年   89篇
  1990年   76篇
  1989年   67篇
  1988年   59篇
  1987年   59篇
  1986年   47篇
  1985年   51篇
  1984年   44篇
  1983年   44篇
  1981年   37篇
  1980年   32篇
  1979年   36篇
  1978年   30篇
  1976年   40篇
  1975年   31篇
  1974年   26篇
  1973年   32篇
  1972年   26篇
排序方式: 共有8495条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.

Background  

The prevalence of tobacco usage in Native American adults and adolescents is higher than any other racial or ethnic group, yet biological risk and protective factors underlying tobacco use in this ethnic group remain unknown. A genome scan for loci associated with tobacco use phenotypes was performed with data collected from a community sample of Mission Indians residing in Southwest California.  相似文献   
5.
6.
BACKGROUND: Brachial artery reactivity (BAR), carotid intima-media thickness (IMT), and applanation tonometry for evaluation of total arterial compliance may provide information about preclinical vascular disease. We sought to determine whether these tests could be used to identify patients with coronary artery disease (CAD) without being influenced by their ability to identify those at risk for CAD developing. METHODS: We studied 100 patients and compared 3 groups: 35 patients with known CAD; 34 patients with symptoms and risk factors but no CAD identified by stress echocardiography (risk group); and 31 control subjects. BAR and IMT were measured using standard methods, and total arterial compliance was calculated by the pulse-pressure method from simultaneous radial applanation tonometry and pulsed wave Doppler of the left ventricular outflow. Ischemia was identified as a new or worsening wall-motion abnormality induced by stress. RESULTS: In a comparison between the control subjects and patients either at risk for developing CAD or with CAD, the predictors of risk for CAD were: age (P =.01); smoking history (P =.002); hypercholesterolemia (P =.002); and hypertension (P =.004) (model R = 0.82; P =.0001). The independent predictors of CAD were: IMT (P =.001); BAR (P =.04); sex (P =.005); and hypertension (P =.005) (model R = 0.80; P =.0001). CONCLUSION: IMT, BAR, and traditional cardiovascular risk factors appear to identify patients at risk for CAD developing. However, only IMT was significantly different between patients at risk for developing CAD and those with overt CAD.  相似文献   
7.
CD154-specific antibody therapy prevents allograft rejection in many experimental transplant models. However, initial clinical transplant trials with anti-CD154 have been disappointing suggesting the need for as of yet undetermined adjuvant therapy. In rodents, donor antigen (e.g., a donor blood transfusion), or mTOR inhibition (e.g., sirolimus), enhances anti-CD154's efficacy. We performed renal transplants in major histocompatibility complex-(MHC) mismatched rhesus monkeys and treated recipients with combinations of the CD154-specific antibody IDEC-131, and/or sirolimus, and/or a pre-transplant donor-specific transfusion (DST). Therapy was withdrawn after 3 months. Triple therapy prevented rejection during therapy in all animals and led to operational tolerance in three of five animals including donor-specific skin graft acceptance in the two animals tested. IDEC-131, sirolimus and DST are highly effective in preventing renal allograft rejection in primates. This apparently clinically applicable regimen is promising for human renal transplant trials.  相似文献   
8.
9.
OBJECTIVE: Our purpose was to assess whether legislative action influenced the role of obstetrician-gynecologists as primary care physicians. STUDY DESIGN: An observational study was performed on the basis of a questionnaire sent to 410 obstetrician-gynecologists and 27 medical directors of managed-care organizations. RESULTS: Of 67% of obstetrician-gynecologists and 96% of medical directors who responded, there was agreement as to the content of primary care, but a minority (38%) of obstetrician-gynecologists identified themselves as primary care providers. A minority of medical directors (35%) felt that obstetrician-gynecologists should serve in that role. Both obstetrician-gynecologists and medical directors felt that legislation had little impact. CONCLUSION: The reticence of obstetrician-gynecologists to assume a major role in primary care appears to be the result of an uneasiness with accepting a more comprehensive role in patient management and gatekeeping. They appear comfortable with the more traditional roles but feel that training and experience has not prepared them well for the management of more complex medical problems. (Am J Obstet Gynecol 1998;178:1222-8.)  相似文献   
10.
Background Coronary heart disease (CHD) is a major cause of morbidity and mortality in the UK. The aim of this study was to screen inpatients with mild or borderline intellectual disability, many of whom also have mental illness, for risk factors for CHD. Methods Cross sectional survey. Participants were interviewed, measured and had blood samples taken. Results Of the 53 participants, 20 (37.7%) were overweight and 18 (34.0%) obese. The mean body mass index (BMI) of those participants prescribed regular antipsychotics was higher than those who were not. Nine (20.9%) had waist circumference measurements placing them at increased risk of CHD and 21 (48.8%) were at substantially increased risk. Twenty-eight (52.8%) were current smokers. Of the 49 participants who had their blood pressure measured, 3 (6.1%) had readings above the reference range. Of the 19 participants who had random blood tests, one (5.3%) had an elevated cholesterol level. Conclusions In this population there was a high prevalence of two risk factors for CHD (obesity and smoking), requiring ongoing monitoring and long-term measures to reduce risk.  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