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   2217篇
  免费   174篇
  国内免费   12篇
耳鼻咽喉   20篇
儿科学   142篇
妇产科学   52篇
基础医学   242篇
口腔科学   69篇
临床医学   269篇
内科学   436篇
皮肤病学   35篇
神经病学   104篇
特种医学   244篇
外科学   235篇
综合类   58篇
预防医学   218篇
眼科学   101篇
药学   79篇
  1篇
肿瘤学   98篇
  2021年   17篇
  2019年   14篇
  2018年   16篇
  2017年   26篇
  2016年   21篇
  2015年   33篇
  2014年   42篇
  2013年   61篇
  2012年   68篇
  2011年   71篇
  2010年   73篇
  2009年   76篇
  2008年   71篇
  2007年   48篇
  2006年   63篇
  2005年   73篇
  2004年   53篇
  2003年   55篇
  2002年   63篇
  2001年   60篇
  2000年   59篇
  1999年   57篇
  1998年   98篇
  1997年   98篇
  1996年   106篇
  1995年   68篇
  1994年   61篇
  1993年   59篇
  1992年   41篇
  1991年   46篇
  1990年   41篇
  1989年   62篇
  1988年   58篇
  1987年   66篇
  1986年   45篇
  1985年   48篇
  1984年   35篇
  1983年   34篇
  1982年   24篇
  1981年   28篇
  1980年   14篇
  1979年   22篇
  1978年   19篇
  1977年   17篇
  1976年   15篇
  1975年   24篇
  1974年   24篇
  1973年   17篇
  1970年   15篇
  1967年   11篇
排序方式: 共有2403条查询结果,搜索用时 15 毫秒
1.
2.
3.
Rate of flow of aqueous humor determined from measurements of aqueous flare   总被引:2,自引:0,他引:2  
Measurement of light scattered in the anterior chamber can provide important clinical information about the eye. In this study, a scanning ocular spectrofluorophotometer was used to measure scattering in the anterior chamber. Pathologic scattering (flare) was induced by argon laser photocoagulation of the iris in pigmented rabbits. The spectrally corrected intensity of the flare in inflamed eyes decreased as the inverse 2.2 power of the wavelength of the illuminating beam. The strongest signal with this instrument was measured at 470 nm. Diurnal variation of normal and spontaneous scatter from the aqueous humor was measured in nine pigmented rabbits entrained to a 12-hr light/12-hr dark cycle and in eight human subjects. A technique is described for determining the rate of flow of aqueous humor from scattered light when the transfer rate of scattering substance into the anterior chamber is constant. This technique was used to study changes in flow over the diurnal cycle. The rate of flow in human subjects during sleep was 60% of the rate during waking hours. In rabbits, the rate was lowest (44% of maximum) during the 6 hr after the lights were turned on, and were greatest just before the lights were turned on. These findings confirm previous studies of the circadian rhythm of aqueous humor flow in rabbits and humans.  相似文献   
4.

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   
5.
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.
The prevalence of selected illnesses and symptoms during 1977-85 was compared between 175 employees potentially exposed to the organophosphate insecticide chlorpyrifos and 335 matched controls with no history of exposure to organophosphates. Subjects were subdivided into three exposure intensity groups on the basis of job title and air monitoring data for dose response testing. This classification scheme was shown roughly to correlate with plasma cholinesterase inhibition in the workers. No statistically significant differences in illness or prevalence of symptoms were observed between the exposed and unexposed groups or among the three exposure subgroups. Potentially exposed employees did report symptoms of dizziness and of malaise and fatigue relatively more often than subjects from the comparison group; however, further analyses by exposure level, process area, or time did not support a relation with exposure. No cases of peripheral neuropathy were seen among the exposed workers. Although the sample size was small and the statistical power limited, the cumulative exposures likely to have been experienced by this workforce exceed those to be expected for individuals using the product as recommended. The absence of exposure related adverse effects, including neurological impairment, is reassuring.  相似文献   
10.
A synchronous occurrence of large bowel adenocarcinoma and extragenital malignant mixed mesodermal tumour (MMMT) is reported. This case represents the sixth extragenital MMMT reported in the literature.  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