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   1047878篇
  免费   82144篇
  国内免费   6325篇
耳鼻咽喉   13456篇
儿科学   34906篇
妇产科学   28931篇
基础医学   150573篇
口腔科学   28457篇
临床医学   96964篇
内科学   200619篇
皮肤病学   23285篇
神经病学   81604篇
特种医学   40411篇
外国民族医学   327篇
外科学   155190篇
综合类   34254篇
现状与发展   6篇
一般理论   391篇
预防医学   81819篇
眼科学   24068篇
药学   77575篇
  65篇
中国医学   5627篇
肿瘤学   57819篇
  2021年   9867篇
  2019年   9099篇
  2018年   12493篇
  2017年   10009篇
  2016年   11134篇
  2015年   13221篇
  2014年   17660篇
  2013年   25119篇
  2012年   33698篇
  2011年   35651篇
  2010年   21911篇
  2009年   20168篇
  2008年   31760篇
  2007年   33344篇
  2006年   33613篇
  2005年   32024篇
  2004年   30446篇
  2003年   29141篇
  2002年   27894篇
  2001年   47746篇
  2000年   48746篇
  1999年   40999篇
  1998年   11601篇
  1997年   10527篇
  1996年   10512篇
  1995年   10070篇
  1994年   9355篇
  1993年   8636篇
  1992年   32402篇
  1991年   31596篇
  1990年   31143篇
  1989年   29982篇
  1988年   27270篇
  1987年   27417篇
  1986年   25509篇
  1985年   24659篇
  1984年   18441篇
  1983年   15545篇
  1982年   9303篇
  1979年   16872篇
  1978年   12230篇
  1977年   10319篇
  1976年   9757篇
  1975年   10186篇
  1974年   12324篇
  1973年   11850篇
  1972年   10889篇
  1971年   10115篇
  1970年   9381篇
  1969年   8731篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A selected ion monitoring assay for thiodiglycollic acid in urine is described. Urine samples are analysed by combined gas chromatography-mass spectrometry as their dibutyl esters using pimelic acid as an internal standard. Rapid analysis was achieved by the simplification of sample preparation. The assay has proved to be reliable, with a detection limit of less than 0.5 mumol/l. The excretion of large amounts of thiodiglycollic acid in premature babies urine has been confirmed, with the greatest excretion occurring from those neonates born with a gestational age of 30 wk or less.  相似文献   
992.
The late results--up to six years--after axillo-femoral bypass reconstruction are reported for 85 patients with leg ischaemia who were regarded as poor-risk patients for aortic bypass surgery, or who had aortic graft infection. Velour-Dacron grafts and expanded polytetrafluoroethylene (PTFE, Gore-Tex)--grafts have been used. The cumulative patency rate (life table) six years after graft implantation was 64% (PTFE-grafts) and 58% (Velour-Dacron grafts). The corresponding cumulative limb salvage rate six years after graft implantation was 88% when PTFE grafts were used and 77% when Velour-Dacron grafts were used. Our results demonstrate that axillo-femoral reconstruction is a useful procedure with a good patency rate 6 years after implantation. This procedure should be considered when dealing with poor risk patients with severe leg ischaemia.  相似文献   
993.
994.
Synovectomy of the knee in patients with hemophilia presenting in countries with demographic characteristics that make central referral difficult is the subject of this article. Ten patients, six surgeons, and two countries contributed to this study, which demonstrated that approximately 40% of these patients had no further hemarthroses into the affected joint and the remainder had reduced frequency and severity of bleeding. Continuous passive motion has an important place in postoperative management, and manipulation with the patient under anesthesia is of doubtful value. The possible relationship between diminished range of movement and a successful outcome in terms of abolition of hemorrhage is explored. One patient underwent synovectomy of the knee without complication; the other nine suffered significant complications.  相似文献   
995.
We tested whether hypoglycemia, like hypoxia, would preferentially destroy GABAergic nerve cells in the neocortex. To this end, rat neocortex explants dissected from 6-day-old rat pups and cultured up to a developmental stage approximately comparable to that of the newborn human neocortex, were exposed to hypoglycemia for different periods. Quantitative light microscopic and immunocytochemical evaluation of the cultures demonstrated that hypoglycemia does not preferentially destroy GABAergic but rather non-GABAergic neurons, a finding quite opposite to what was found after hypoxia. Recent biochemical data from other laboratories which seem to support this difference in neuronal vulnerability are discussed. It is concluded that perinatal hypoglycemia may not form such a serious threat with respect to the genesis of epilepsy as does hypoxia.  相似文献   
996.
997.
Out of 24 patients with laryngeal papillomatosis 6 (5 female, 1 male) suffered from repeated relapses and underwent long-term treatment with alpha-IFN-therapy. Age at onset of the disease: 1 5/12-16 2/12 years. Duration of illness: 1-7 years, with several relapses were treated surgically and with laser-coagulation. Three out of 6 patients had a tracheal cannula and were cauterized by podophylline at 2-4 week intervals. IFN was given in dosages of 5-20 X 10(4) U/kg 2 or 3 times a week. IFN-dosage for each patient was determined using the induction kinetics of (2'-5')-oligo(A)synthetase (OAS) in the mononuclear cells of the circulating blood of patients with laryngeal papillomatosis. A continuous effect could be achieved by the dose of IFN determined in the described way always before OAS activity decreased to its initial level. All 6 patients responded favorably to the alpha-IFN-therapy. Two patients treated only with IFN showed remission without relapses. In 2 cases IFN was successfully used to prevent relapses after surgical treatment and laser-coagulation. In 2 patients with papillomatosis extending into the main bronchi the disease could only be brought to a standstill, i.e. it was not necessary to remove the papillomas. Two out of 3 patients with laryngeal papillomatosis could be decannulated. Long-term therapy following the above described principles is efficient and without significant side-effects. Three patients are in treatment for more than 3 10/12 years.  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