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   1284379篇
  免费   96487篇
  国内免费   1617篇
耳鼻咽喉   16670篇
儿科学   41626篇
妇产科学   35569篇
基础医学   191933篇
口腔科学   35256篇
临床医学   120332篇
内科学   251064篇
皮肤病学   27443篇
神经病学   103513篇
特种医学   47454篇
外国民族医学   265篇
外科学   181500篇
综合类   26151篇
现状与发展   3篇
一般理论   582篇
预防医学   107161篇
眼科学   28731篇
药学   93940篇
  7篇
中国医学   2046篇
肿瘤学   71237篇
  2018年   13908篇
  2017年   10687篇
  2016年   11607篇
  2015年   13411篇
  2014年   18490篇
  2013年   28185篇
  2012年   38570篇
  2011年   40970篇
  2010年   23635篇
  2009年   22779篇
  2008年   38667篇
  2007年   41351篇
  2006年   40815篇
  2005年   39931篇
  2004年   38393篇
  2003年   36710篇
  2002年   35580篇
  2001年   56677篇
  2000年   57669篇
  1999年   48637篇
  1998年   13719篇
  1997年   12543篇
  1996年   12922篇
  1995年   12202篇
  1994年   11283篇
  1993年   10551篇
  1992年   38620篇
  1991年   38044篇
  1990年   36813篇
  1989年   35617篇
  1988年   33038篇
  1987年   32341篇
  1986年   30865篇
  1985年   29120篇
  1984年   22222篇
  1983年   19402篇
  1982年   11518篇
  1981年   10459篇
  1979年   21205篇
  1978年   15566篇
  1977年   12952篇
  1976年   11971篇
  1975年   12945篇
  1974年   15761篇
  1973年   15509篇
  1972年   14652篇
  1971年   13663篇
  1970年   12909篇
  1969年   12210篇
  1968年   11348篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
A case is presented which demonstrates the potential utility of the extracranial-intracranial bypass procedure for the treatment of vasospasm after subarachnoid hemorrhage. Extracranial-intracranial bypass surgery offers another alternative to the treatment of patients with vasospasm who have failed aggressive medical management.  相似文献   
93.
94.
The composition of the clientele from an ophthalmological practitioner's office is described with special reference to the occurrence of glaucoma and disc haemorrhages (h in singular; hh in plural). This study could not be planned as an epidemiological survey and gives no clue to sensitivity or specificity of hh in glaucoma. During a period of about 10 years ending with 1986 there were 731 patients with h and/or glaucoma. When detected, 185 patients had h but no glaucoma, 33 had both h and glaucoma and 513 had glaucoma but no h. During the follow-up period hh were detected in 83 cases of glaucoma, and glaucoma developed in 27 cases with hh. The detection rate of hh among glaucoma was low but steady, indicating that hh may occur at any stage of the glaucoma process. This study shows no predilection for hh in cases with general hypertension or diabetes, nor is the frequency of hh among pseudoexfoliation cases significantly lower than among cases without this stigma.  相似文献   
95.
Isotretinoin (Accutane Capsules) is a synthetic vitamin A compound used for treatment of recalcitrant cystic acne. It has numerous ocular toxic side effects which include anterior segment inflammation, dry eye syndrome, contact lens intolerance, altered refraction, photosensitivity, and reduced night vision. Eye care practitioners should be aware of these potential side effects and be prepared to communicate with the prescribing physician if side effects present.  相似文献   
96.
97.
. Neutrophil-mediated tissue damage has been implicated in the pathogenesis of diarrhoea-associated haemolytic uraemic syndrome (D+ HUS). This study evaluates priming and activation of the neutrophil oxidative burst in D+ HUS using chemiluminescent techniques. Peripheral blood neutrophils from 11 children with acute D+ HUS were examined. No difference was found in the oxidative burst of neutrophils from patients and controls. Serum elastase levels were measured in 8 patients and found to be significantly elevated. Although elastase results suggest neutrophil activation, chemiluminescence studies do not confirm this in the peripheral blood neutrophil. This does not support a significant role for circulating agents in priming and activating the peripheral blood neutrophil. Received August 17, 1995; received in revised form and accepted November 27, 1995  相似文献   
98.
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   
99.
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated.  相似文献   
100.
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