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   317639篇
  免费   11154篇
  国内免费   1953篇
耳鼻咽喉   2590篇
儿科学   10288篇
妇产科学   5446篇
基础医学   35156篇
口腔科学   4130篇
临床医学   27143篇
内科学   59709篇
皮肤病学   2525篇
神经病学   29041篇
特种医学   13295篇
外国民族医学   9篇
外科学   48649篇
综合类   7666篇
现状与发展   4篇
一般理论   164篇
预防医学   30039篇
眼科学   6604篇
药学   20343篇
  26篇
中国医学   2017篇
肿瘤学   25902篇
  2023年   972篇
  2022年   1955篇
  2021年   3577篇
  2020年   2287篇
  2019年   3234篇
  2018年   25029篇
  2017年   19802篇
  2016年   22185篇
  2015年   4656篇
  2014年   5986篇
  2013年   7526篇
  2012年   17029篇
  2011年   31392篇
  2010年   24654篇
  2009年   16944篇
  2008年   28235篇
  2007年   30890篇
  2006年   9767篇
  2005年   11270篇
  2004年   11809篇
  2003年   12124篇
  2002年   9997篇
  2001年   2039篇
  2000年   1786篇
  1999年   1837篇
  1998年   1952篇
  1997年   1689篇
  1996年   1229篇
  1995年   1252篇
  1994年   1022篇
  1993年   957篇
  1992年   825篇
  1991年   799篇
  1990年   747篇
  1989年   659篇
  1988年   640篇
  1987年   599篇
  1986年   505篇
  1985年   585篇
  1984年   611篇
  1983年   562篇
  1982年   735篇
  1981年   630篇
  1980年   587篇
  1979年   397篇
  1978年   366篇
  1977年   366篇
  1976年   317篇
  1975年   287篇
  1974年   315篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
113.

Background  

This study aimed to investigate the signs of oral dryness in relation to different salivary variables and to correlate subjective complaints of oral dryness with salivary flow rate.  相似文献   
114.
On September 7-8, 1988, health professionals attended a national seminar at the National Institute of Public Cooperation and Child Development in New Delhi to review policies of each government department in India that dispenses essential drugs to PHC workers. Another objective included the need to agree on what essential drugs should be distributed by the various types of PHC workers. The consensus of the group was that the different levels of health services and competence of the PHC workers should determine the basic list of PHC essential drugs. In addition, the morbidity pattern in the community, safety, effectiveness, and cost of the drugs must also determine which drugs are essential. Anganwadi workers/village health guides should all have a kit with 17 of the 75 essential drugs, such as vitamin A solution, oral rehydration solution packets, choloroquine, and chlorine tablets. In addition to the same 17 drugs, all subcenters should have in stock aspirin, metoclopramide, oral contraceptives, methergin in both tablet and injection form, and activated charcoal. Each PHC center should have all of the above and the remaining 53 drugs which include antibiotics, bronchodialators, eye drops, injections, vaccines (e.g., DPT and BCG), ointments, antileprosy drugs, and snake venom. The quantity of each drug should be based on the morbidity pattern, seasonal trend, and sickness load of the area. All PHC workers should attend inservice training where tested and effective training modules and charts in each local language are used to learn how to judiciously prescribe these drugs. Further, this essential drug program should be continuously monitored and evaluated.  相似文献   
115.
(18)F-Fluoride PET allows noninvasive evaluation of regional bone metabolism and has the potential to become a useful tool for assessing patients with metabolic bone disease and evaluating novel drugs being developed for these diseases. The main PET parameter of interest, termed K(i), reflects regional bone metabolism. The aim of this study was to compare the long-term precision of (18)F-fluoride PET with that of biochemical markers of bone turnover assessed over 6 mo. METHODS: Sixteen postmenopausal women with osteoporosis or significant osteopenia and a mean age of 64 y underwent (18)F-fluoride PET of the lumbar spine and measurements of biochemical markers of bone formation (bone-specific alkaline phosphatase and osteocalcin) and bone resorption (urinary deoxypyridinoline) at baseline and 6 mo later. Four different methods for analyzing the (18)F-fluoride PET data were compared: a 4k 3-compartmental model using nonlinear regression analysis (K(i-4k)), a 3k 3-compartmental model using nonlinear regression analysis (K(i-3k)), Patlak analysis (K(i-PAT)), and standardized uptake values. RESULTS: With the exception of a small but significant decrease in K(i-3k) at 6 mo, there were no significant differences between the baseline and 6-mo values for the PET parameters or biochemical markers. The long-term precision, expressed as the coefficient of variation (with 95% confidence interval in parentheses), was 12.2% (9%-19%), 13.8% (10%-22%), 14.4% (11%-22%), and 26.6% (19%-40%) for K(i-3k), K(i-PAT), mean standardized uptake value, and K(i-4k), respectively. For comparison, the precision of the biochemical markers was 10% (7%-15%), 18% (13%-27%), and 14% (10%-21%) for bone-specific alkaline phosphatase, osteocalcin, and urinary deoxypyridinoline, respectively. Intraclass correlation between the baseline and 6-mo values ranged from 0.44 for K(i-4k) to 0.85 for K(i-3k). No significant correlation was found between the repeated mean standardized uptake value measurements. CONCLUSION: The precision and intraclass correlation observed for K(i-3k) and K(i-PAT) was equivalent to that observed for biochemical markers. This study provided initial data on the long-term precision of (18)F-fluoride PET measured at the lumbar spine, which will aid in the accurate interpretation of changes in regional bone metabolism in response to treatment.  相似文献   
116.
Diverticula arising from the mitral valve are very rare. They are usually detected by echocardiography as masses arising from the cardiac valves. We present a case of an incidental finding of a diverticulum arising from the mitral valve. This was initially detected by transesophageal echocardiography, and later confirmed by pathologic appearance. The case illustrates the unique findings on echocardiography that would help to differentiate diverticula from other valvular masses.  相似文献   
117.
118.
119.
120.
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