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   1032492篇
  免费   80261篇
  国内免费   5204篇
耳鼻咽喉   13153篇
儿科学   34937篇
妇产科学   29002篇
基础医学   149821篇
口腔科学   28362篇
临床医学   94823篇
内科学   199262篇
皮肤病学   23238篇
神经病学   81311篇
特种医学   39645篇
外国民族医学   328篇
外科学   153511篇
综合类   29477篇
现状与发展   12篇
一般理论   388篇
预防医学   79857篇
眼科学   23530篇
药学   75726篇
  18篇
中国医学   3915篇
肿瘤学   57641篇
  2021年   8490篇
  2019年   8481篇
  2018年   11806篇
  2017年   9398篇
  2016年   10472篇
  2015年   12304篇
  2014年   16445篇
  2013年   23776篇
  2012年   31797篇
  2011年   33786篇
  2010年   20288篇
  2009年   18894篇
  2008年   30811篇
  2007年   32489篇
  2006年   32816篇
  2005年   31580篇
  2004年   30255篇
  2003年   29064篇
  2002年   27864篇
  2001年   47725篇
  2000年   48974篇
  1999年   41253篇
  1998年   11796篇
  1997年   10762篇
  1996年   10661篇
  1995年   10247篇
  1994年   9515篇
  1993年   8767篇
  1992年   32532篇
  1991年   31765篇
  1990年   31270篇
  1989年   30109篇
  1988年   27359篇
  1987年   27508篇
  1986年   25595篇
  1985年   24718篇
  1984年   18482篇
  1983年   15585篇
  1982年   9314篇
  1979年   16890篇
  1978年   12240篇
  1977年   10332篇
  1976年   9771篇
  1975年   10186篇
  1974年   12324篇
  1973年   11852篇
  1972年   10885篇
  1971年   10119篇
  1970年   9378篇
  1969年   8727篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
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   
993.
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   
994.
995.
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   
996.
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   
997.
998.
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   
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