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   1346254篇
  免费   97835篇
  国内免费   2216篇
耳鼻咽喉   19020篇
儿科学   44117篇
妇产科学   38756篇
基础医学   196410篇
口腔科学   36146篇
临床医学   115630篇
内科学   266168篇
皮肤病学   27282篇
神经病学   105942篇
特种医学   52708篇
外国民族医学   366篇
外科学   208715篇
综合类   27298篇
现状与发展   1篇
一般理论   386篇
预防医学   98045篇
眼科学   30674篇
药学   102518篇
  1篇
中国医学   2571篇
肿瘤学   73551篇
  2018年   14041篇
  2017年   10509篇
  2016年   11731篇
  2015年   13559篇
  2014年   18836篇
  2013年   27960篇
  2012年   39250篇
  2011年   41824篇
  2010年   24424篇
  2009年   22887篇
  2008年   39705篇
  2007年   42801篇
  2006年   43005篇
  2005年   42243篇
  2004年   40439篇
  2003年   39105篇
  2002年   38258篇
  2001年   58632篇
  2000年   59938篇
  1999年   51188篇
  1998年   14928篇
  1997年   13332篇
  1996年   13477篇
  1995年   12717篇
  1994年   12112篇
  1993年   11220篇
  1992年   41207篇
  1991年   40524篇
  1990年   40038篇
  1989年   38841篇
  1988年   36251篇
  1987年   35465篇
  1986年   33833篇
  1985年   32264篇
  1984年   24084篇
  1983年   20948篇
  1982年   12575篇
  1981年   11140篇
  1979年   22721篇
  1978年   15975篇
  1977年   13819篇
  1976年   13026篇
  1975年   14250篇
  1974年   16717篇
  1973年   16111篇
  1972年   15352篇
  1971年   14260篇
  1970年   13234篇
  1969年   12746篇
  1968年   11993篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
P W Sanders  G A Herrera  G V Ball 《Nephron》1988,48(2):121-125
Scleroderma renal crisis (SRC) is defined as sudden development of accelerated hypertension, hyperreninemia, and acute renal failure in a patient with progressive systemic sclerosis (PSS). Although the diagnosis of PSS is generally straightforward because of dermal fibrosis, we report 2 patients who had PSS with SRC without the characteristic fibrotic skin changes of scleroderma. PSS should be considered in the differential diagnosis of unexplained acute renal failure and accelerated hypertension even though the cutaneous fibrotic manifestations of the disease may be absent.  相似文献   
992.
We have examined some of the binding characteristics and the autoradiographic distribution of binding sites for Na125I (I-Na) in airway tissue from the guinea-pig, monkey, pig, rat, mouse and from man. Basal I-Na (100 pM) binding levels were extremely low. However, in the presence of ascorbic acid (10 microM) or dithiothreitol (10 microM), I-Na binding was markedly increased in guinea-pig trachea, with lesser increases detected in monkey and rat trachea and in monkey and human bronchus. In guinea-pig trachea, ascorbic acid-induced I-Na binding was not saturable within the concentration range 100-620 pM and could not be reduced by washout. Autoradiography revealed that in central airways, I-Na binding was localized at or near the interface of the airway epithelium and submucosa in small clusters, apparently involving one or two cells per focus. The physiological significance of these binding sites is yet to be established, although they may be involved in intracellular iodine storage.  相似文献   
993.
994.
995.
996.
Volunteers trained by a social worker did a telephone screening of 716 elderly persons waiting for elective surgery to determine in advance of admission their need for social services. On the basis of their findings patients were given a risk rating by a social worker. While the survey was experienced positively by patients, volunteers, and social workers, the results do not establish its value in terms of shortened length of stay. Aging females living alone required the greatest amount of social work and had the longest length of stay. This group requires further study, along with the connection between intensity of illness with social problem vulnerability. The study raises other important questions critical to programming for an increasingly older population.  相似文献   
997.
Adult mosquitoes of the Anopheles quadrimaculatus complex were collected from Montgomery County, AL (MON) and Alachua County, FL, (KBG) and laboratory stocks of species A and B were established through a selection procedure employing isofemale lines. Progeny from a cross of species B females to ORL males were usually semisterile females and sterile males. Progeny of the reciprocal cross were also semisterile females and sterile males, but the sex ratio was variable and ranged from normal to no males because of male mortality during the pupal stage. Conspecific crosses between strains from the two locations resulted in fertile offspring. Crosses between the sibling species from the two locations invariably gave semisterile females and sterile males (or lethal effects). This evidence confirmed previous data from hybridization and electrophoretic analyses of field populations indicating that Anopheles quadrimaculatus is a species complex.  相似文献   
998.
Progressive peripheral cone dysfunction   总被引:1,自引:0,他引:1  
A 22-year-old man had a three-year history of progressive day blindness, most notably peripherally, and denied difficulty with central vision or color vision. Visual function studies demonstrated a diffuse dysfunction of the photopic system and normal scotopic function. The central cone function, however, was essentially normal. Visual acuity was 20/20 in each eye, results on AO-HRR and Ishihara color plate testing were normal, color naming visual fields demonstrated color discrimination in the central 10 degrees, and foveal adaptation was normal.  相似文献   
999.
1000.
Clinicopathologic correlation of pigmented epiretinal membranes   总被引:1,自引:0,他引:1  
We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes.  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