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   1356篇
  免费   70篇
  国内免费   11篇
耳鼻咽喉   13篇
儿科学   129篇
妇产科学   12篇
基础医学   135篇
口腔科学   37篇
临床医学   189篇
内科学   252篇
皮肤病学   15篇
神经病学   72篇
特种医学   252篇
外科学   83篇
综合类   35篇
预防医学   53篇
眼科学   12篇
药学   101篇
  1篇
肿瘤学   46篇
  2021年   4篇
  2020年   7篇
  2019年   8篇
  2018年   13篇
  2017年   11篇
  2016年   8篇
  2015年   22篇
  2014年   24篇
  2013年   21篇
  2012年   32篇
  2011年   28篇
  2010年   47篇
  2009年   50篇
  2008年   35篇
  2007年   20篇
  2006年   28篇
  2005年   37篇
  2004年   28篇
  2003年   36篇
  2002年   35篇
  2001年   30篇
  2000年   24篇
  1999年   38篇
  1998年   89篇
  1997年   88篇
  1996年   92篇
  1995年   65篇
  1994年   56篇
  1993年   49篇
  1992年   30篇
  1991年   29篇
  1990年   17篇
  1989年   41篇
  1988年   35篇
  1987年   43篇
  1986年   21篇
  1985年   36篇
  1984年   22篇
  1983年   21篇
  1982年   16篇
  1981年   17篇
  1980年   10篇
  1979年   5篇
  1978年   6篇
  1977年   8篇
  1976年   9篇
  1975年   8篇
  1971年   5篇
  1936年   3篇
  1934年   3篇
排序方式: 共有1437条查询结果,搜索用时 31 毫秒
1.
2.
3.
Congenital herpes simplex retinitis   总被引:2,自引:0,他引:2  
An 1,810-g girl born at 37 weeks of gestation had true congenital herpes simplex virus type 2 infection. The neonate was born with hypo-pigmented skin lesions, brain lesions, and old heavily pigmented retinal scars in the posterior pole. There was no active ocular disease. Viral cultures, immunoperoxidase stains, and antibody determination by enzyme-linked immunosorbent assay were all positive for herpes simplex virus. Treatment with acyclovir healed the lesions within ten days. The clinical and laboratory findings indicated that the herpetic infection probably occurred in the second trimester.  相似文献   
4.
Poly{acrylamide-co-[2-(acryloyloxy)ethyltrimethylammonium chloride]} (1) , Poly{acrylamide-co-[2-(methacryloyloxy)ethyltrimethylammonium chloride]} (2) and Poly{acrylamide-co-[3-(acryloylamino)propyltrimethylammonium chloride]} (3) with cationic monomeric unit mole fractions of 8, 25, and 50 mol-%, and the corresponding homopolymers were characterized with respect to their molecular dimensions in 1 M sodium chloride solution at 25°C in the molecular weight range from 200000 to 16000000, using light-scattering and viscometric measurements. It was possible to establish correlations between molecular weight, intrinsic viscosity and radius of gyration. Whereas a steady increase in the exponents of the [η] vs. M- and 〈R2G0,5 vs. M-relationships can be observed with increasing charge density, there is an initial decrease in the values of the exponents for 2 and 3 , when 8 mol-% of the cationic monomer is inserted into poly-acrylamide. If the charge density is increased further, these values can also be seen to rise steadily. The findings are explained by the different structures in solution, which are formed by the copolymers and homopolymers investigated due to their chemical structure. The radii of gyration were calculated from the intrinsic viscosities with the aid of the Flory-Fox equation. However, neither the results obtained with the Flory-Fox constant Φ0= 3,69. 1024 mol?1, nor those with the value of Φ0= 2,10. 1024 mol?1 showed good agreement with the experimentally recorded data.  相似文献   
5.

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   
6.
7.
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   
8.
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   
9.
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   
10.
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   
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