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   1459176篇
  免费   106729篇
  国内免费   10397篇
耳鼻咽喉   20163篇
儿科学   45507篇
妇产科学   42293篇
基础医学   211713篇
口腔科学   40006篇
临床医学   128276篇
内科学   281298篇
皮肤病学   29158篇
神经病学   110807篇
特种医学   56334篇
外国民族医学   425篇
外科学   218921篇
综合类   45841篇
现状与发展   23篇
一般理论   347篇
预防医学   105270篇
眼科学   34408篇
药学   114729篇
  103篇
中国医学   8973篇
肿瘤学   81707篇
  2021年   13344篇
  2019年   12055篇
  2018年   16484篇
  2017年   12657篇
  2016年   13722篇
  2015年   16929篇
  2014年   22676篇
  2013年   30689篇
  2012年   42770篇
  2011年   46468篇
  2010年   27518篇
  2009年   25181篇
  2008年   42113篇
  2007年   45199篇
  2006年   45895篇
  2005年   44922篇
  2004年   41458篇
  2003年   40240篇
  2002年   39178篇
  2001年   64930篇
  2000年   66797篇
  1999年   57056篇
  1998年   17094篇
  1997年   15263篇
  1996年   14886篇
  1995年   14042篇
  1994年   13190篇
  1992年   44432篇
  1991年   43779篇
  1990年   43112篇
  1989年   41878篇
  1988年   39108篇
  1987年   38180篇
  1986年   36357篇
  1985年   34679篇
  1984年   25599篇
  1983年   22279篇
  1982年   13192篇
  1979年   24231篇
  1978年   16837篇
  1977年   14549篇
  1976年   13736篇
  1975年   15205篇
  1974年   17834篇
  1973年   17278篇
  1972年   16474篇
  1971年   15313篇
  1970年   14173篇
  1969年   13681篇
  1968年   12865篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease. Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India  相似文献   
112.
Internal eye wall resection in the management of uveal melanoma   总被引:3,自引:0,他引:3  
Twenty patients with presumed uveal melanoma underwent internal eye wall resection. It was the primary procedure in 13 patients who had tumours within 2 disc diameters of the optic nerve head and was combined with external resection in the remainder. Malignant melanoma was confirmed histologically in 15 patients; the diagnosis was a benign tumour in the other 5. The length of follow-up ranged from 2 to 37 (mean 19) months. In all cases the retina was completely attached at the time of last examination. The visual acuity ranged from 20/40 to hand movements; nine patients had an acuity of 20/400 or better. At the time of writing no metastatic disease or local recurrence had developed in any of the 15 patients in whom malignant melanoma was diagnosed.  相似文献   
113.
We describe a mild form of drug-induced pemphigus in a woman with essential arterial hypertension treated with captopril. Complete recovery was observed three weeks after the therapy had been discontinued.  相似文献   
114.
115.
116.
Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs.  相似文献   
117.
118.
The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status.  相似文献   
119.
In der Behandlung von Frakturen spielt die Analgesie eine wesentliche Rolle. Es stellt sich daher die Frage, ob in der Klinik h?ufig eingesetzte Analgetika wie Tramadol oder Diclofenac negative Wirkungen auf die Knochenbruchheilung haben.  相似文献   
120.
Background : Methimazole, an anti-thyroid drug, was recently found to be useful in the treatment of systemic lupus erythematosus and other autoimmune diseases. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity and reduced soluble IL-2 receptors. In the present study we examined the effects of methimazole and propylthiouracil on a rat model of experimental colitis.
Methods : Colitis was induced by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB). Two weeks prior to induction of colitis, rats were treated by either methimaziole (0.04%) or propylthiouracil (0.01%) in drinking water after a week of free access to water. Rats were sacrificed 48 h or 7 days after induction of colitis. The colon was isolated, rinsed with ice-cold water and weighed. Damage was assessed both macroscopically and microscopically and myeloperoxidase (MPO) activity determined.
Results : All treated rats were hypothyroid as manifested by a significant elevation of thyroid stimulating hormone (TSH), by comparison with the control groups (mean -1.82±0.40 versus 0.11±0.02 mmol/L, respectively). The inflammatory response elicited by TNB resulted in severe mucosal damage 48 h after damage induction, which persisted for 7 days. Pre-treatment with either methimazole 0.04% or propylthiouracil 0.01% significantly decreased mucosal damage macroscopically (lesion area, lesion score and segmental weight) microscopically and also significantly decreased MPO level at both time points ( P <0.01).
Conclusions : Methimazole and propylthiouracil significantly reduce mucosal damage and colonic weight in a rat model of colitis. The mode by which they do so remains to be studied.  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