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   530348篇
  免费   27649篇
  国内免费   495篇
耳鼻咽喉   6682篇
儿科学   16928篇
妇产科学   12537篇
基础医学   92623篇
口腔科学   12347篇
临床医学   48593篇
内科学   95488篇
皮肤病学   11869篇
神经病学   34042篇
特种医学   19768篇
外国民族医学   53篇
外科学   78106篇
综合类   7613篇
现状与发展   2篇
一般理论   107篇
预防医学   38543篇
眼科学   11959篇
药学   41466篇
  1篇
中国医学   1126篇
肿瘤学   28639篇
  2019年   3894篇
  2018年   5743篇
  2017年   4128篇
  2016年   4875篇
  2015年   5366篇
  2014年   7125篇
  2013年   10509篇
  2012年   15604篇
  2011年   17418篇
  2010年   9970篇
  2009年   8831篇
  2008年   15721篇
  2007年   17457篇
  2006年   16953篇
  2005年   16277篇
  2004年   15896篇
  2003年   15278篇
  2002年   14792篇
  2001年   22439篇
  2000年   22981篇
  1999年   18929篇
  1998年   5241篇
  1997年   4371篇
  1996年   4404篇
  1995年   4126篇
  1992年   14421篇
  1991年   15824篇
  1990年   15955篇
  1989年   15628篇
  1988年   14316篇
  1987年   14202篇
  1986年   13169篇
  1985年   12688篇
  1984年   9397篇
  1983年   8002篇
  1982年   4179篇
  1979年   8939篇
  1978年   6382篇
  1977年   5150篇
  1976年   5505篇
  1975年   6613篇
  1974年   7419篇
  1973年   7158篇
  1972年   6597篇
  1971年   6310篇
  1970年   5889篇
  1969年   5469篇
  1968年   5162篇
  1967年   4621篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
1. The frequent occurrence of hypothalamo-pituitary dysfunction in patients with eating disorders as well as prior reports that nutritional and endocrine status influence pituitary morphology, led us to hypothesize that pituitary size and shape may be altered in patients with eating disorders. 2. Magnetic resonance imaging (MRI) does not use ionizing radiation and is currently one of the most feasible modalities available to study the pituitary gland in vivo. Using MRI, we have previously reported in a preliminary study that female patients with eating disorders had significantly smaller pituitary glands than controls. In addition MRI excluded any pituitary mass lesions. 3. In this report, we confirm our previous MRI findings and provide further evidence of pituitary abnormalities in an expanded sample of eating disorder patients. Preliminary data on pituitary volume estimates from MRI scans are provided for a subset of patients and controls.  相似文献   
113.
Surgical treatment of acoustic neuroma has been reviewed in the medical literature, but assessment of outcome from the patient's perspective has received little attention. The Acoustic Neuroma Association (A.N.A.) is a large organization of acoustic neuroma patients which provides information and support services. This article reports the subjective assessment of symptoms, diagnosis, treatment, and outcome as evaluated by 541 A.N.A. members. This retrospective study presents an extensive overview of the experience of acoustic neuroma patients treated at a variety of institutions, and provides a unique perspective not previously represented in the medical literature.  相似文献   
114.
Clinical pharmacokinetics-pharmacodynamics of anticancer drugs   总被引:3,自引:0,他引:3  
  相似文献   
115.
116.
The paper describes the examinations of 353 patients with various cardiovascular pathologies and changes in the end-portion of the ECG ventricular complex. For that purpose potassium chloride, obsidan, orthostatic and hyperventilation tests were used. The examinations demonstrated that the ECG changes were of functional nature in 178 patients, of organic nature in 155 patients and of mixed nature in 20 patients which was important for reliable diagnostic and expertise conclusions.  相似文献   
117.
Congenital esophageal cysts in adults   总被引:1,自引:0,他引:1  
Sixteen adult patients with congenital esophageal cysts were operated on between 1957 and 1979. Preoperatively, 7 patients (44%) were asymptomatic and the cyst was found incidentally on a routine chest roentgenogram. Esophageal symptoms were present in only 3 patients (19%), whereas most symptomatic patients had precordial sensations or arrhythmias. A correct preoperative diagnosis was made in only 1 patient. After enucleation of the cyst, preoperative symptoms were alleviated in all patients and short-term results were excellent. However, long-term follow-up 13.2 +/- 5.6 (+/- standard deviation) years later revealed moderate reflux in 9 (64%) of the surviving 14 patients. During esophagoscopy, macroscopic esophagitis was found in 12 (92%) of 13 patients. On histological examination of specimens obtained by forceps biopsy, esophagitis was present in 10 (77%) of 13 patients and included Barrett esophagus in 2. We conclude that, despite excellent early results, long-term follow-up of patients who undergo operation for congenital esophageal cysts is indicated because of the increased incidence of reflux esophagitis.  相似文献   
118.
The isolated perfused working rat heart model of cardiopulmonary bypass was used to assess whether (a) allopurinol pretreatment enhances resistance to normothermic (30 min) or hypothermic (4 h) ischemia; (b) addition of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) to cardioplegic and/or reperfusion solutions are protective; (c) any protective effects are additive. With normothermic ischemia, allopurinol pretreatment improved recovery of aortic flow from its control value of 25 +/- 3% to 48 +/- 6% (P less than 0.05). Similarly, SOD plus CAT used during both ischemia and reperfusion improved recovery of aortic flow from a control value of 28 +/- 4% to 48 +/- 6% (P less than 0.05). However, various combinations of the two types of intervention afforded no additive protection. Under hypothermic (21 degrees C) conditions, allopurinol pretreatment was not effective, whereas SOD and CAT added during ischemia and reperfusion improved recovery of aortic flow from its control value of 53 +/- 4% to 69 +/- 5% (P less than 0.05). This value was similar to allopurinol pretreatment and SOD plus CAT added during ischemia and reperfusion (69 +/- 6%: P less than 0.05). These results provide further evidence that reperfusion-induced free radical formation may adversely affect postischemic recovery of function. The absence of an additive effect suggests a common mechanism of action, which is likely to involve the free radical-generating enzyme xanthine oxidase; however, other mechanisms may exist. Our results further support the use of antifree radical intervention in conjunction with cardioplegia to protect the heart during ischemia and reperfusion.  相似文献   
119.
1. The evidence is accumulating to suggest that glycine, the simplest amino acid, is conditionally essential in man. Benzoic acid, by conjugation with glycine to form hippuric acid, is known to deplete the free glycine pool of the body. Glycine is one substrate for the enzyme glutathione synthase (EC 6.3.2.3) and in the inborn error of metabolism in which glutathione synthase function is defective, increased quantities of 5-oxoproline are excreted in the urine. 2. An oral dose of 4-10 g sodium benzoate was given to six normal adults to deplete the metabolic pool of glycine, and the urinary excretion of 5-oxoproline was followed for 6 h. In five of the six, a significant increase in the urinary 5-oxoproline was seen within 3 h. 3. These findings show that 5-oxoprolinuria can result from limited glycine availability, and may provide a useful test for assessing glycine sufficiency in a range of physiological and pathological states.  相似文献   
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