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   1620篇
  免费   96篇
  国内免费   18篇
耳鼻咽喉   1篇
儿科学   120篇
妇产科学   18篇
基础医学   156篇
口腔科学   47篇
临床医学   205篇
内科学   326篇
皮肤病学   16篇
神经病学   81篇
特种医学   235篇
外科学   212篇
综合类   37篇
一般理论   1篇
预防医学   98篇
眼科学   12篇
药学   52篇
  1篇
肿瘤学   116篇
  2022年   3篇
  2021年   8篇
  2020年   13篇
  2019年   16篇
  2018年   24篇
  2017年   21篇
  2016年   21篇
  2015年   32篇
  2014年   41篇
  2013年   45篇
  2012年   59篇
  2011年   49篇
  2010年   64篇
  2009年   56篇
  2008年   50篇
  2007年   42篇
  2006年   45篇
  2005年   41篇
  2004年   37篇
  2003年   28篇
  2002年   37篇
  2001年   28篇
  2000年   25篇
  1999年   36篇
  1998年   91篇
  1997年   91篇
  1996年   98篇
  1995年   62篇
  1994年   61篇
  1993年   55篇
  1992年   34篇
  1991年   31篇
  1990年   20篇
  1989年   46篇
  1988年   40篇
  1987年   51篇
  1986年   32篇
  1985年   41篇
  1984年   24篇
  1983年   22篇
  1982年   17篇
  1981年   22篇
  1980年   11篇
  1979年   8篇
  1978年   7篇
  1977年   11篇
  1976年   11篇
  1975年   8篇
  1973年   3篇
  1970年   3篇
排序方式: 共有1734条查询结果,搜索用时 93 毫秒
1.
2.

Background  

The aims of this study were to examine the extent to which higher intellectual abilities protect higher socio-economic groups from functional decline and to examine whether the contribution of intellectual abilities is independent of childhood deprivation and low birth weight and other socio-economic and developmental factors in early life.  相似文献   
3.
4.
Defecography in multiple sclerosis patients with severe constipation   总被引:3,自引:0,他引:3  
Gill  KP; Chia  YW; Henry  MM; Shorvon  PJ 《Radiology》1994,191(2):553
  相似文献   
5.
Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease.  相似文献   
6.
SUMMARY The interferons are natural glycoproteins secreted in response to various stimuli, including viral infection. They have antiviral, antiproliferative and immunomodulatory effects on different target cell populations. Since recombinant human interferons have become available, they have been tested in a wide range of malignancies. They are well established in the treatment of hairy cell leukaemia, chronic myelogenous leukaemia and multiple myeloma. Although they have documented activity against lymphoma, melanoma, renal cell cancer and carcinoid tumours, their role in the treatment of these tumours is less clear. In the common solid tumours, such as lung cancer and colorectal cancer, the use of interferons remains experimental. Here we will summarise their practice applications in oncology, using randomised studies where available to establish their place in multi-modality treatment. We will not discuss their use as antiviral or immunomodulating agents in viral and autoimmune diseases, multiple sclerosis or after organ transplantation.  相似文献   
7.
Cohen syndrome: fertility in a female patient   总被引:1,自引:0,他引:1  
In this report we describe fertility in an adult female with Cohen syndrome. She gave birth to a son, now 1.5 years old, with discrete facial stigmata and slight psychomotor retardation.  相似文献   
8.
K1K2Pu, a recombinant t-PA/u-PA chimera with increased thrombolytic potency in animal models of venous and arterial thrombosis, which consists of amino acids 1 to 3 and 87 to 274 of human tissue-type plasminogen activator (t-PA) and amino acids 138 to 411 of human single chain urokinase-type plasminogen activator (scu-PA), was produced and conditioned for use in patients. Chinese hamster ovary cells were transfected with an expression plasmid containing the K1K2Pu cDNA, high producer cell lines were selected and scaled up in 800 cm2 roller bottles, and 350 ml conditioned cell culture medium was harvested 3 to 7 times at 2 to 5 day intervals. Batches of 21 +/- 4 liter (mean +/- SD, n = 28) containing 1.8 +/- 0.6 mg/l of K1K2Pu related antigen were purified by chromatography on Copper chelate-Sepharose and immunoadsorption on an insolubilized murine monoclonal antibody (MA-1C8). Yields were 8.6 +/- 3.4 mg K1K2Pu per batch with a specific activity of 83,000 +/- 44,000 IU/mg. The final material, obtained at a concentration of approximately 0.7 mg/ml, was dialyzed against 0.3 M NaCl, 0.02 M Tris-HCl buffer, pH 7.5, containing 0.01% Tween 80 and 10 KIU/ml aprotinin. It was homogeneous on SDS-PAGE, contained 6.5 +/- 6.9 percent two chain material and the contamination with murine monoclonal antibody was less than 0.1 percent. After filtration of pools of 3 to 5 selected batches on 0.22 microns Millipore filters the material was sterile and virus free by routine screening; it was obtained at a concentration of approximately 0.5 mg/ml with a specific activity of 110,000 +/- 16,000 IU/mg (mean +/- SD, n = 3) and an endotoxin content of 0.5 to 7 units/mg. Bolus injection at a dose of 1 mg/kg in mice did not produce weight loss within 8 days. Thus, this material appears to be suitable for the investigation on a pilot scale of the pharmacokinetic and thrombolytic properties of K1K2Pu in patients with thromboembolic disease.  相似文献   
9.
Chronic low back pain: comparison of bone SPECT with radiography and CT   总被引:1,自引:0,他引:1  
Ryan  PJ; Evans  PA; Gibson  T; Fogelman  I 《Radiology》1992,182(3):849
  相似文献   
10.
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