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   3137591篇
  免费   222497篇
  国内免费   8400篇
耳鼻咽喉   42996篇
儿科学   99858篇
妇产科学   85658篇
基础医学   441129篇
口腔科学   88197篇
临床医学   284846篇
内科学   616074篇
皮肤病学   73624篇
神经病学   255849篇
特种医学   120903篇
外国民族医学   800篇
外科学   475525篇
综合类   63017篇
现状与发展   5篇
一般理论   1146篇
预防医学   235604篇
眼科学   71020篇
药学   231560篇
  10篇
中国医学   6544篇
肿瘤学   174123篇
  2019年   24022篇
  2018年   34206篇
  2017年   26340篇
  2016年   30466篇
  2015年   34311篇
  2014年   47130篇
  2013年   70490篇
  2012年   93674篇
  2011年   99002篇
  2010年   59586篇
  2009年   57223篇
  2008年   93216篇
  2007年   98821篇
  2006年   100723篇
  2005年   96636篇
  2004年   93126篇
  2003年   89700篇
  2002年   86952篇
  2001年   155604篇
  2000年   159594篇
  1999年   134652篇
  1998年   37541篇
  1997年   33156篇
  1996年   33397篇
  1995年   32272篇
  1994年   29623篇
  1993年   27729篇
  1992年   104459篇
  1991年   100356篇
  1990年   97347篇
  1989年   94038篇
  1988年   86122篇
  1987年   84414篇
  1986年   79117篇
  1985年   75554篇
  1984年   55902篇
  1983年   47348篇
  1982年   27356篇
  1981年   24336篇
  1979年   49465篇
  1978年   34446篇
  1977年   29463篇
  1976年   26950篇
  1975年   28854篇
  1974年   34292篇
  1973年   32479篇
  1972年   30490篇
  1971年   28404篇
  1970年   26460篇
  1969年   25327篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
The facility of direct real-time endocardial electrogram recording offered by newer pacemaker models can be helpful in the assessment of normal pacemaker function. Confirmation of the main hallmarks of sensing (amplitude, slew rate, and timing of the electrogram) can be achieved. Assessment of pacing capture also can be made; techniques for further analysis using external signal averaging can enhance this. The measurement of atrial and ventricular electrograms by telemetry has led to alterations in the protocol used at implantation to allow for the input impedance of the sensing circuit of the pacemaker. Accurate measurements of retrograde VA conduction times and confirmation of normal upper rate limit behavior of ODD pacemakers can be achieved simply and reliably using telemetered electrograms from the permanent pacemaker system.  相似文献   
993.
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   
994.
Eight lymphatic fluid collections were drained percutaneously. There were no immediate or late complications. Seven patients had follow-up; 1 required surgical drainage of a residual or recurrent lymphocele, and another had reaccumulated fluid in a lymphocele which was detected on autopsy. The remaining lymphatic collections responded to percutaneous drainage. Percutaneous drainage is safe and can be an effective tool in the management of lymphatic collections.  相似文献   
995.
A method for measuring flow based on the shifting of the rephasing pulse following slice selection in partial saturation is described. The technique is based on a partial saturation sequence and retains much of the high signal which is a feature of the use of this sequence. Images obtained while encoding for the flow signal compated with those when not encoding appear very similar.  相似文献   
996.
We report the results of 322 ultrasonically guided percutaneous fine-needle biopsies of focal intrahepatic lesions. The technique is original in several respects; it is an aspiration of both the lesion and normal-looking liver, and it includes both cytology and histology when the tiny cores are obtained. Cytology included Papanicolaou and Giemsa staining and other special staining when necessary. Sensitivity was 88.6% and specificity was 100% in the diagnosis of malignancy. Out of 141 metastases, 14 false negatives, 5 misclassifications, and 122 correct diagnoses were obtained. Out of 69 hepatomas the correct diagnosis of malignancy was made in 63 patients and of these the correct classification in 49. Complications occurred in six patients and marked hemorrhage in four. This technique is a simple, accurate, safe method for the diagnosis of focal intrahepatic lesions.  相似文献   
997.
A family with idiopathic torsion dystonia (dystonia musculorum deformans) was seen in a peripheral clinic in the Richtersveld in the north-western Cape. This rare inherited form of neurological disease has maximal prevalence in individuals of Ashkenazi Jewish ancestry, and there is controversy regarding the exact mode of inheritance. The kindred documented in this study was of mixed ancestry (Cape Coloured), and autosomal recessive inheritance was suggested by the finding of affected male and female siblings born to normal parents in an isolated inbred community.  相似文献   
998.
999.
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