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   4439篇
  免费   200篇
  国内免费   17篇
耳鼻咽喉   44篇
儿科学   83篇
妇产科学   98篇
基础医学   202篇
口腔科学   100篇
临床医学   450篇
内科学   691篇
皮肤病学   44篇
神经病学   141篇
特种医学   78篇
外科学   463篇
综合类   151篇
一般理论   15篇
预防医学   1249篇
眼科学   84篇
药学   381篇
  1篇
中国医学   59篇
肿瘤学   322篇
  2023年   135篇
  2022年   136篇
  2021年   338篇
  2020年   188篇
  2019年   667篇
  2018年   433篇
  2017年   248篇
  2016年   146篇
  2015年   146篇
  2014年   231篇
  2013年   286篇
  2012年   202篇
  2011年   195篇
  2010年   110篇
  2009年   105篇
  2008年   115篇
  2007年   79篇
  2006年   70篇
  2005年   62篇
  2004年   65篇
  2003年   57篇
  2002年   38篇
  2001年   35篇
  2000年   27篇
  1999年   23篇
  1998年   45篇
  1997年   46篇
  1996年   35篇
  1995年   51篇
  1994年   50篇
  1993年   35篇
  1992年   29篇
  1991年   18篇
  1990年   6篇
  1989年   8篇
  1988年   3篇
  1986年   3篇
  1985年   16篇
  1984年   17篇
  1983年   22篇
  1982年   12篇
  1981年   13篇
  1980年   14篇
  1979年   12篇
  1978年   13篇
  1977年   7篇
  1976年   18篇
  1975年   14篇
  1974年   16篇
  1973年   8篇
排序方式: 共有4656条查询结果,搜索用时 250 毫秒
11.
12.
SUMMARY: In patients with chronic renal failure (CRF), hyperleptinaemia has been widely reported, but the exact mechanisms leading to elevated leptin levels are unclear. Impaired renal clearance of leptin and the influence of other hormones may be important. In this study, we measured serum leptin levels in 150 patients on haemodialysis, peritoneal dialysis or in the predialysis phase of CRF. Furthermore, we measured plasma levels of insulin, growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as well as plasma levels of triacylglycerols and total low density lipoprotein (LDL)- and high density lipoprotein (HDL)-cholesterol. We observed significantly elevated levels of leptin, particularly in female patients, and leptin was shown to correlate significantly with insulin, total and LDL-cholesterol and log triacylglycerols. Leptin was inversely correlated with GH concentrations, but was not correlated with IGF-1 levels. Despite the multiple correlations established between leptin levels and other variables, only hyperinsulinaemia in CRF seems to be important as a determinator of leptin levels.  相似文献   
13.
A cohort study of tobacco use,diet, occupation,and lung cancer mortality   总被引:1,自引:0,他引:1  
In 1966, a cohort of White males aged 35 or over, who were policy-holders with the Lutheran Brotherhood Insurance Society (United States), completed a mail questionnaire on tobacco use, diet, and demographic characteristics. During the 20 years of follow-up, 219 lung cancer deaths occurred. Besides the strong relationship with cigarette smoking, we observed an effect on lung cancer risk among current users of cigars or pipes who were nonsmokers of cigarettes (relative risk [RR]=3.5, 95 percent confidence interval[CI]=1.0–12.6) or who were past/occasional users of cigarettes (RR=2.7, CI=1.4–5.3). In addition, elevated risks (from 1.5 to 2.6) of lung cancer were found among craftsmen and laborers, with the highest risks among subjects who worked in the mining or manufacturing industry. No association between current (as of 1966) use of beer or hard liquor and lung cancer was observed, although past users were at elevated risk. An inverse association between lung cancer and intake of fruits was observed, and risks of lung cancer were lower among persons in the highest dietary intake quintiles of vitamins A and C. Except for oranges, however, none of the inverse associations with fruits or dietary nutrients had statistically significant trends. The findings from this cohort study add to the evidence of an adverse effect of cigar/pipe smoking and possibly protective effect of dietary factors on lung cancer risk.  相似文献   
14.
Internal rates of return were used to examine the status of pharmacist supply in the United States between the years 1987-1991. Age-earnings profiles were estimated for pharmacists, college graduates and high school graduates. Rates of return to pharmacists and college graduates were compared and a ratio of the pharmacist rate to the college graduate rate was computed for each year. Results suggest a shortage of pharmacists in the United States. Enrollments in pharmacy schools and adopted changes in the training of pharmacists are discussed in relation to their effects on the pharmacist labour market.  相似文献   
15.
Summary. The first American programme for chemically dependent medical students at the University of Tennessee, Memphis is described. The goals of the Aid for the Impaired Medical Student (AIMS) Program are to provide confidential treatment for chemically dependent medical students, to assure that recovering students are able to resume their education, and to protect patients and others from the harm that may be caused by impaired students. The Program is administered by the AIMS Council, consisting of medical professionals and elected student representatives. The Council oversees the management of cases, including investigation of students who may be impaired, intervention when chemical dependency is suspected, diagnostic evaluation, treatment and aftercare, and post-recovery advocacy for students. The Program's experience includes 18 cases of suspected chemical dependency, with four self-referrals and 14 students referred by third parties. Eleven students have been diagnosed as chemically dependent and have completed treatment programmes. Nine have maintained recovery and eight have graduated. One student subsequently relapsed and committed suicide. Obstacles in programme implementation have involved absence of perceived need, the view that chemically dependent students should be dismissed from school, and reluctance of students to report classmates. Resources have included highly respected student representatives, a supportive administration, assistance of the impaired physicians programme, and medical insurance and professional courtesy to defray costs. Although the number treated has been modest, the AIMS Program is an important vehicle for training students regarding chemical dependency and their professional obligations toward impaired colleagues.  相似文献   
16.
Many factors have led to a movement from the emphasis of the 1960s and 1970s on departmental expansion towards an emphasis on cost-effective undergraduate medical education emphasizing the 'art' as well as the 'science' of medicine. In January 1985 a questionnaire was sent under the auspices of the Undergraduate Education Committee of the Association of Professors of Obstetrics and Gynecology to all chairmen of departments of obstetrics and gynecology in the USA and Canada seeking their opinions about these trends and information about the educational programmes in their departments. The information from this study indicates that the chairmen are aware of and responding to this new direction in medical education. A stabilization of teaching staff and clerkship sizes and the emphasis on clinical as well as cognitive evaluation, despite recognition of the cost of the former, shows active interventions towards these ends. An emphasis on education in 'basic' as compared to 'subspecialty' areas which is independent of the subspecialty of the academic chairman also supports this trend.  相似文献   
17.
测定了在温度310.65K、323.15K和压力3.13~7.54MPa条件下的气液平衡数据,实验结果与文献值具有较好的一致性。用TRK状态方程对实验所得数据进行关联,取得了较满意的结果。  相似文献   
18.
Summary: The Internet contains a vast amount of medically relevant information. In order to access this information, however, many networks require one to master applications written in UNIX, an operating system considered by many not to be user friendly. Although these tools may be available on the campus, it is difficult to teach their use unless there is some immediate benefit to the already busy user. From that standpoint, it is important for instructors to realize that common UNIX applications can be utilized as classroom tools to significantly enhance the learning experience by facilitating teacher/student communication. Also, whilst the student enjoys greater communication with the instructor (and with other students) he/she is also becoming adept at using information management tools.  相似文献   
19.
20.
Leukemia clusters around nuclear facilities in Britain   总被引:1,自引:0,他引:1  
He bas been retained for the defense by British Nuclear Fuelsplc in two suits in which leukemia and non-Hodgkin's lymphoma have been alleged to result from radiation exposures due to the operation of the nuclear reprocessing plant at Sellafield. This paper has been sent to the senior authors of the papers reporting clusters of leukemia or other malignancy in the vicinity of nuclear facilities in Britain and their comments invited. Subject to considerations of space and CCC style, these comments will be published as submited.  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