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   863630篇
  免费   57678篇
  国内免费   1716篇
耳鼻咽喉   11258篇
儿科学   28344篇
妇产科学   20935篇
基础医学   131486篇
口腔科学   27116篇
临床医学   75345篇
内科学   169531篇
皮肤病学   20171篇
神经病学   62618篇
特种医学   30685篇
外国民族医学   102篇
外科学   123861篇
综合类   16079篇
现状与发展   3篇
一般理论   217篇
预防医学   68090篇
眼科学   19306篇
药学   63464篇
  3篇
中国医学   2995篇
肿瘤学   51415篇
  2021年   8841篇
  2019年   8623篇
  2018年   12352篇
  2017年   9439篇
  2016年   9936篇
  2015年   11227篇
  2014年   15310篇
  2013年   21738篇
  2012年   30454篇
  2011年   31906篇
  2010年   17991篇
  2009年   16615篇
  2008年   28015篇
  2007年   30129篇
  2006年   29778篇
  2005年   28689篇
  2004年   27751篇
  2003年   26029篇
  2002年   23725篇
  2001年   40599篇
  2000年   41216篇
  1999年   34203篇
  1998年   9284篇
  1997年   7837篇
  1996年   8101篇
  1995年   7602篇
  1994年   7063篇
  1993年   6469篇
  1992年   25349篇
  1991年   25214篇
  1990年   24425篇
  1989年   24182篇
  1988年   21929篇
  1987年   21203篇
  1986年   20096篇
  1985年   18878篇
  1984年   13849篇
  1983年   11663篇
  1982年   6442篇
  1979年   12375篇
  1978年   8694篇
  1977年   7277篇
  1976年   6976篇
  1975年   7770篇
  1974年   9010篇
  1973年   8649篇
  1972年   8085篇
  1971年   7496篇
  1970年   7303篇
  1969年   6731篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%).  相似文献   
53.
54.
55.
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease. Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India  相似文献   
56.
57.
The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status.  相似文献   
58.
59.
A retrospective analysis of results of treatment of 104 patients with fractures of long tubular bones associated with injuries of peripheral nerves has shown complex therapy to be necessary. Main components of this treatment were biogenic stimulators, vitamin B12, spasmolytic and dehydration drugs in combination with electrophoresis with potassium iodide and thermal procedures. Rapid disturbance of conductivity of nerve trunks after trauma should be followed by revision of the given segment of the extremity in order to remove hematoma and make reposition of displaced fragments of the bone, which can provide recovery of the disturbed function of the nerve.  相似文献   
60.
Thirteen cases of primary appendicular adenocarcinoma are reported. This rare tumour usually presents as acute appendicitis. The correct diagnosis is rarely entertained before or during surgery. The main treatment choice lies between appendicectomy alone and appendicectomy followed by right hemicolectomy. There are anatomical reasons for advising the latter and survival figures from the literature tend to support this preference. The cases reported here indicate that in the period 1972-1984, in the North West Region, there was a slight preference for appendicectomy alone. The additional procedure of right hemicolectomy did not confer any clear-cut survival advantage.  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