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   3451867篇
  免费   287725篇
  国内免费   13626篇
耳鼻咽喉   48338篇
儿科学   111835篇
妇产科学   89274篇
基础医学   546789篇
口腔科学   90863篇
临床医学   307476篇
内科学   616796篇
皮肤病学   91134篇
神经病学   293863篇
特种医学   137288篇
外国民族医学   686篇
外科学   536202篇
综合类   102685篇
现状与发展   23篇
一般理论   2270篇
预防医学   289076篇
眼科学   78818篇
药学   237729篇
  23篇
中国医学   9655篇
肿瘤学   162395篇
  2021年   54975篇
  2020年   35028篇
  2019年   58067篇
  2018年   71164篇
  2017年   54205篇
  2016年   59802篇
  2015年   73961篇
  2014年   108109篇
  2013年   173275篇
  2012年   91799篇
  2011年   91688篇
  2010年   116561篇
  2009年   121145篇
  2008年   79660篇
  2007年   83058篇
  2006年   93724篇
  2005年   89273篇
  2004年   91419篇
  2003年   82563篇
  2002年   72772篇
  2001年   110020篇
  2000年   104081篇
  1999年   102876篇
  1998年   66072篇
  1997年   63490篇
  1996年   61438篇
  1995年   56887篇
  1994年   51143篇
  1993年   47677篇
  1992年   72815篇
  1991年   69875篇
  1990年   66377篇
  1989年   64844篇
  1988年   60005篇
  1987年   58803篇
  1986年   55199篇
  1985年   55207篇
  1984年   49831篇
  1983年   45397篇
  1982年   41899篇
  1981年   39669篇
  1980年   37189篇
  1979年   40812篇
  1978年   35728篇
  1977年   32697篇
  1976年   30039篇
  1975年   28948篇
  1974年   29661篇
  1973年   28570篇
  1972年   26525篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A total of 102 patients were examined, 32 of these with true eczema, 38 with exudative mycosis of the soles, and 32 with eczema etiologically related to a fungal infection. Analysis of the immune and biochemical reactions in the examinees has shown a marked reduction of adenyl nucleotides in the leukocytic suspension and neutrophils of patients with a mycotic infection as against those with true eczema. The lowest creatine phosphate levels were detected in the leukocytic suspension and neutrophils of the patients suffering from eczema etiologically related to mycosis and exudative mycosis of the soles. These results give grounds to search for effective corrective therapy.  相似文献   
992.
993.
This paper reports the changes in prolactin levels after 12 spontaneous and 52 induced pregnancies in 54 women with unambiguous hyperprolactinaemia (median plasma prolactin levels 67.5 ng/ml, range 40-400). Twenty-three of the patients showed radiological evidence of prolactinoma. The pregnancies were induced in 37 patients by bromocriptine, in nine by metergoline, in two by lisuride and in four by other treatments. Of the 64 pregnancies, 16 ended in spontaneous abortion, while 48 went to term. Follow-up was continued for at least 6 months after delivery or until the end of lactation. In a control group of 32 hyperprolactinaemic women (median prolactin 70 ng/ml, range 40-400) not wishing to become pregnant, prolactin changes were similarly registered over a mean period of 15 months without any treatment (range 6-38 months). After pregnancy, a significant downward trend of plasma prolactin was observed in the puerperal women with a 'normalization' rate of 17%. No changes were observed in the 32 controls who did not become pregnant.  相似文献   
994.
Plasma tumor necrosis factor and mortality in critically ill septic patients   总被引:23,自引:0,他引:23  
Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients.  相似文献   
995.
996.
The authors analysed the prevalence of atrioventricular conduction defects and sinus node dysfunction by Holter monitoring in three population groups with similar clinical characteristics: 50 controls (Group I), 17 physically fit subjects with an atrioventricular conduction defect on the resting ECG which was usually asymptomatic (Group II), and 48 professional pilots who were also physically fit but who had no conduction defects on resting ECG (Group III). The 24 hour recordings showed: --a similar incidence of sinus dysrhythmias and atrioventricular conduction defects in the three groups although the frequency of low degree block was a little higher in sportsmen; --a preponderance of the association of first degree block and nocturnal Luciani-Wenckebach periods, sometimes with episodes of Mobitz II block; --the absence of progression to high-degree atrioventricular block. Holter monitoring would therefore seem to be a good method of detecting and following up abnormalities of sinus node function and atrioventricular conduction defects in asymptomatic patients. In addition, it gives a qualitative and quantitative assessment of the recorded changes and provides a means of monitoring their evolution.  相似文献   
997.
The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited.  相似文献   
998.
Thiarubrine A, a dithiacyclohexadiene polyine from the roots of Chaenactis douglasii, and a related dithiacyclohexadiene from Rudbeckia hirta exhibit strong light-independent antibacterial and antifungal activity. This activity is enhanced by exposure to visible light. Visible light also converts the compounds to the corresponding thiophenes. These are antibiotic only when irradiated with UV-A. Dithiacyclohexadienes are the first polyines to exhibit such complex mechanisms of toxicity towards microorganisms.  相似文献   
999.
Summary Split or full thickness eyelid defects resulting from tumor destruction or surgical excision present a dilemma for plastic and reconstructive surgeons. Full thickness eyelid replacement requires composite grafting of the skin, together with tarsal support of its substitute and mucosa. The flap described by Fricke in 1829 was used for reconstruction of anterior lamella in six lower eyelid defects. In three of our cases chondromucosal grafts taken from nasal septum were utilized for posterior lamella repair. The results have been satisfactory from a functional and cosmetic standpoint.  相似文献   
1000.
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