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   1299056篇
  免费   94967篇
  国内免费   2010篇
耳鼻咽喉   18439篇
儿科学   43043篇
妇产科学   38399篇
基础医学   190032篇
口腔科学   35908篇
临床医学   110869篇
内科学   255150篇
皮肤病学   26805篇
神经病学   101059篇
特种医学   50682篇
外国民族医学   369篇
外科学   200523篇
综合类   26890篇
现状与发展   1篇
一般理论   335篇
预防医学   95443篇
眼科学   29542篇
药学   99589篇
  1篇
中国医学   2586篇
肿瘤学   70368篇
  2018年   12332篇
  2016年   10450篇
  2015年   12084篇
  2014年   16618篇
  2013年   25259篇
  2012年   34845篇
  2011年   37234篇
  2010年   21879篇
  2009年   20659篇
  2008年   36057篇
  2007年   39098篇
  2006年   39652篇
  2005年   38920篇
  2004年   37333篇
  2003年   36241篇
  2002年   35775篇
  2001年   58692篇
  2000年   60197篇
  1999年   51214篇
  1998年   14509篇
  1997年   13018篇
  1996年   13298篇
  1995年   12555篇
  1994年   11941篇
  1993年   11029篇
  1992年   41393篇
  1991年   40726篇
  1990年   40234篇
  1989年   39023篇
  1988年   36408篇
  1987年   35668篇
  1986年   34032篇
  1985年   32406篇
  1984年   24163篇
  1983年   21005篇
  1982年   12531篇
  1981年   11076篇
  1979年   22863篇
  1978年   16044篇
  1977年   13867篇
  1976年   13095篇
  1975年   14332篇
  1974年   16830篇
  1973年   16211篇
  1972年   15466篇
  1971年   14361篇
  1970年   13317篇
  1969年   12837篇
  1968年   12071篇
  1967年   10554篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
991.
992.
993.
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   
994.
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   
995.
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   
996.
997.
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   
998.
999.
Two models of hot water washer disinfectors (Decomat 128 and Hospital A, Euroclean Canada Inc; Ontario, Canada) were evaluated by two methods for their efficacy in disinfecting anesthesia equipment. In the first method, three different microbial suspensions were each sealed into 30 capillary tubes. In the second method, corrugated anesthesia tubes were rinsed with suspensions of each of two bacterial strains. The tubes then underwent a standard cycle in the hot water washer disinfectors and were subsequently tested for growth of microorganisms. All experiments were repeated three times, and the temperature was registered in all cases. In the capillary test, growth was rarely detected (13/540 tubes) and the inactivation factor for both apparatus was greater than 5 log10. In the rinse test, no growth was detected. The mean temperature for 15 disinfection cycles was 84.2 +/- 0.8 degrees C for Decomat 128 and 88.9 +/- 0.5 degrees C for Hospital A. However, for Decomat 128 we observed a variation of 3 degrees C from one disinfection cycle to another and a progressive reduction of 2.2 degrees C over a series of five consecutive complete cycles. Both methods gave reproducible results. Under our experimental conditions, both hot water washer disinfectors proved to be efficacious for the disinfection of reusable anesthesia equipment.  相似文献   
1000.
Immunopathologic study of Vogt-Koyanagi-Harada syndrome   总被引:9,自引:0,他引:9  
We studied an enucleated eye from a patient with a 30-year history of Vogt-Koyanagi-Harada syndrome using both conventional and immunohistochemical techniques. Clinically, the eye was in the end stage of Vogt-Koyanagi-Harada syndrome, and was characterized by the absence of inflammation, large areas of chorioretinal scarring, and pigmentary changes. Histopathologic examination showed marked retinal gliosis, extensive chorioretinal adhesion and scar formation, migration of pigment into the retina, and severe retinal pigment epithelial changes. However, foci of mild to moderate nongranulomatous inflammation of the uvea were observed. These foci contained infiltrating cells that were mainly T lymphocytes with B lymphocyte aggregates at the center. Scattered macrophages were also noted in the uvea and retina. These findings suggest that both the cell-mediated and humoral immune arms may play roles in the pathogenesis of Vogt-Koyanagi-Harada syndrome.  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