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   1517篇
  免费   112篇
  国内免费   2篇
耳鼻咽喉   12篇
儿科学   70篇
妇产科学   35篇
基础医学   209篇
口腔科学   67篇
临床医学   82篇
内科学   334篇
皮肤病学   38篇
神经病学   162篇
特种医学   25篇
外科学   166篇
综合类   7篇
预防医学   118篇
眼科学   47篇
药学   108篇
中国医学   14篇
肿瘤学   137篇
  2023年   11篇
  2022年   22篇
  2021年   61篇
  2020年   24篇
  2019年   39篇
  2018年   40篇
  2017年   40篇
  2016年   48篇
  2015年   45篇
  2014年   60篇
  2013年   74篇
  2012年   117篇
  2011年   115篇
  2010年   71篇
  2009年   66篇
  2008年   96篇
  2007年   89篇
  2006年   91篇
  2005年   90篇
  2004年   73篇
  2003年   46篇
  2002年   59篇
  2001年   24篇
  2000年   17篇
  1999年   22篇
  1998年   10篇
  1997年   4篇
  1996年   10篇
  1995年   9篇
  1994年   6篇
  1993年   6篇
  1992年   18篇
  1991年   11篇
  1990年   7篇
  1989年   5篇
  1988年   6篇
  1987年   7篇
  1986年   7篇
  1985年   11篇
  1984年   6篇
  1983年   6篇
  1982年   4篇
  1976年   8篇
  1975年   5篇
  1973年   5篇
  1972年   5篇
  1970年   5篇
  1967年   4篇
  1966年   6篇
  1965年   4篇
排序方式: 共有1631条查询结果,搜索用时 109 毫秒
1.
2.
This study investigated the association of blood pressure with blood oxidative stress-related parameters in normotensive and hypertensive subjects. A cross-sectional design was applied to 31 hypertensive patients and 35 healthy normotensive subjects. All subjects were men between the ages of 35 and 60 years. Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking and current use of any medication. All patients underwent 24-h ambulatory blood pressure monitoring and sampling of blood and urine. Antioxidant enzymes activity, reduced/oxidized glutathione ratio (GSH/GSSG), and lipid peroxidation (malondialdehyde) were determined in erythrocytes. Parameters measured in the plasma of test subjects were plasma antioxidant status, lipid peroxidation (8-isoprostane), plasma vitamin C and E, and the blood pressure modulators renin, aldosterone, endothelin-1 and homocysteine. Daytime systolic and diastolic blood pressures of hypertensives were negatively correlated with plasma antioxidant capacity (r=-0.46, p<0.009 and r=-0.48, p<0.007), plasma vitamin C levels (r=-0.53, p<0.003 and r=-0.44, p<0.02), erythrocyte activity of antioxidant enzymes, and erythrocyte GSH/GSSG ratio, with hypertensives showing higher levels of oxidative stress. Blood pressures showed a positive correlation with both plasma and urine 8-isoprostane. Neither plasma vitamin E nor the assessed blood pressure modulator levels showed significant differences between the groups or correlation with blood pressures. These findings demonstrate a strong association between blood pressure and some oxidative stress-related parameters and suggest a possible role of oxidative stress in the pathophysiology of essential hypertension.  相似文献   
3.
A 16-year-old Thai girl presented with acute unilateral visual loss, proptosis, and ophthalmoparesis. CT demonstrated thickening and enhancement of orbital tissues including the orbital apex. A history of consumption of raw fish, together with the findings of cutaneous migratory swelling and eosinophilia, made the diagnosis of gnathostomiasis likely. Her serum was positive for Gnathostoma spinigerum using an immunoblotting technique. Parasites removed from the skin lesions revealed the typical head bulbs with 4 circumferential rows of hooklets and fine cuticular spines on their surface. Treatment with an antihelminthic and systemic corticosteroids led to resolution of orbital inflammation but left a persistent optic neuropathy marked by nerve fiber bundle visual field loss with normal visual acuity. Gnathostomiasis should be suspected in patients with an orbital apex syndrome who live or travel in an endemic area, have eaten raw fish, and develop a migratory skin rash.  相似文献   
4.
To investigate the usefulness of the frontal assessment battery (FAB) as a brief assessment for diagnosis in patients with dementia, we examined cognitive function using the FAB, Mini-mental state examination (MMSE), Kana-hiroi test, and Raven's colored progressive matrices (RCPM). Subjects were 82 senile patients having amnesia as a complaint including 28 Alzheimer's disease (AD), 14 frontotemporal dementia (FTD), 17 vascular dementia (VD), 13 mild cognitive impairment (MCI), and 10 healthy persons. We discussed the difference of scores in different types of dementia. In the FAB, the scores of healthy persons and MCI were much higher compared with the scores of all types of dementia. There were high correlation between FAB and MMSE, Kana-hiroi test, and RCPM. Although some subjects showed normal score in MMSE and/or RCPM, they showed low score in FAB. Based on this, FAB is efficient for the differential diagnosis of dementia as brief screening tool.  相似文献   
5.
Foreign bodies embedded in the retina and choroid that cannot be extracted by a magnet and require vitreous surgery for their removal comprise a separate group. A retrospective review of 40 consecutive cases (between 1977-1990) showed that this type of trauma frequently accompanied extensive ocular damage, including corneal and or scleral perforation, disruption of the lens, significant vitreous hemorrhage, retinal and choroid hemorrhage, and retinal detachment. Intraoperative and late complications occurred frequently, making the visual and structural outcomes of such eyes uncertain; therefore, another alternative must be sought that might improve the prognosis of these eyes. In this review, we emphasize (1) the time elapsed between the accident and the removal of the foreign body and (2) the final visual acuity and the time before the surgery.  相似文献   
6.
The surface-spreading synaptonemal complex (SC) technique was employed to analyze spermatocytes and oocytes of rainbow trout in order to visualize the process of autosome and sex chromosome synapsis in this species. The structure of lateral elements (LEs) of the SC and the chromosome synapsis process at the stages of leptotene, zygotene and pachytene are described. Comparative analysis of SCs of spermatocytes and oocytes showed a difference in the synaptic process, i.e. in spermatocytes all LEs were synapsed before the appearance of centromeric regions in the biarmed elements, while in the oocytes some fully synapsed LEs, including the centromeric region of the biarmed elements, were found together with fully or partially unsynapsed LEs. In males the sex chromosome synapsis starts only after all autosomes have synapsed. Irregular synapses involving three or four LEs were found in 3.4% of the cells analyzed in mid or late zygotene. Multivalents were found in males and females. Some aspects of initial meiotic development and their implications in rainbow trout cytogenetics, genetics and evolution are discussed.  相似文献   
7.
To elucidate the mechanisms of metastasis, we established two sublines HPC-1H5 with a highly liver metastatic cell line and HPC-1P5a with a highly peritoneal disseminating cell line, which were sequentially selected from the parental pancreatic cancer cell line HPC-1. Using these three cell lines, we investigated several biological properties and mRNA levels of differentially-expressed genes involved in cancer metastasis by cDNA macroarray. Microscopic findings for the three cell lines were the same. The tumorigenicity, in vitro growth ability, motile activity, adhesive activity and the production of IL-8 of metastatic sublines were higher than those of parental HPC-1 cells. Particularly, HPC-1H5 cells showed clearly higher levels of IL-8 expression and tumors of HPC-1H5 cells grew faster and bigger than those of HPC-1P5a cells. In cDNA macroarray analysis of HPC-1H5 cells, 22 genes were up-regulated and 44 genes were down-regulated compared with parental HPC-1 cells. In HPC-1P5a cells, 9 genes were up-regulated and 28 genes were down-regulated compared with parental HPC-1 cells. This study provides a demonstration of global gene expression analysis of pancreatic cancer cells with liver metastasis and peritoneal dissemination. Furthermore, our results provide a new insight into the study of liver metastasis and peritoneal dissemination of human pancreatic cancer. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
8.
9.
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