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   1107篇
  免费   104篇
  国内免费   7篇
耳鼻咽喉   3篇
儿科学   28篇
妇产科学   6篇
基础医学   131篇
口腔科学   10篇
临床医学   185篇
内科学   157篇
皮肤病学   15篇
神经病学   119篇
特种医学   285篇
外科学   64篇
综合类   25篇
一般理论   1篇
预防医学   84篇
眼科学   16篇
药学   53篇
肿瘤学   36篇
  2021年   8篇
  2019年   12篇
  2018年   16篇
  2016年   11篇
  2015年   13篇
  2014年   17篇
  2013年   11篇
  2012年   24篇
  2011年   15篇
  2010年   23篇
  2009年   19篇
  2008年   24篇
  2007年   39篇
  2006年   34篇
  2005年   26篇
  2004年   33篇
  2003年   20篇
  2002年   19篇
  2001年   16篇
  2000年   20篇
  1999年   21篇
  1998年   27篇
  1997年   25篇
  1996年   21篇
  1995年   21篇
  1994年   31篇
  1993年   27篇
  1992年   19篇
  1991年   22篇
  1990年   35篇
  1989年   44篇
  1988年   44篇
  1987年   48篇
  1986年   41篇
  1985年   34篇
  1984年   38篇
  1983年   33篇
  1982年   19篇
  1981年   27篇
  1980年   27篇
  1979年   23篇
  1978年   30篇
  1977年   19篇
  1976年   12篇
  1975年   16篇
  1974年   20篇
  1973年   10篇
  1971年   12篇
  1969年   9篇
  1968年   7篇
排序方式: 共有1218条查询结果,搜索用时 31 毫秒
101.
A test of platelet adhesiveness   总被引:2,自引:0,他引:2  
  相似文献   
102.
Surveillance of symptoms following MMR vaccine in children   总被引:3,自引:0,他引:3  
  相似文献   
103.
In a retrospective study of 163 pancreatic sonograms, five internal echo patterns were correlated with the ultimate clinical diagnoses. Attention to the internal echo patterns of the pancreas can provide useful information in diagnosing pancreatic disease, including identification of abnormalities in glands of normal size and contour.  相似文献   
104.
In vitro, Trichomonas vaginalis produces contact-dependent cytotoxicity in which the monolayers are disrupted and monolayer cells die. In contrast, when cell-free filtrates of T. vaginalis culture supernatants are applied to a monolayer, detachment occurs but cell viability is maintained. Growth of T. vaginalis in culture results in a dramatic fall in pH. Both in systems where T. vaginalis grew in physical contact with McCoy cells and where they were physically separate, monolayers still disrupted; but the rate of death of McCoy cells significantly decreased when pH was rigidly controlled. This would indicate that cell death attributed to contact-dependent cytotoxicity is in part due to the drop in pH when T. vaginalis is grown in vitro.  相似文献   
105.
106.
Two species of tree frog of the genus Litoria, namely L. splendida and L. rothii have been reported to change the compositions of their host-defence skin peptide profiles in summer and winter. L. splendida produces the potent smooth muscle active caerulein [pEQDY(SO3H)TGWMDF-NH2] in summer, but in winter much of the caerulein is hydrolysed to the less active desulfated form; in addition, caerulein 1.2 [pEQDY(SO3H)TGWFDF-NH2] (which has only some 50% of the smooth muscle activity of caerulein) is released and acts via CCK2R. In contrast, Litoria rothii shows a most unexpected seasonal change of peptides. In summer it exudes caerulein together with a range of potent caerin antimicrobials and nNOS active peptides. In winter, none of the antibiotic or nNOS active caerin peptides are expressed. The major peptides produced by the skin glands in winter are caerulein 1.2 and rothein 1 (SVSNIPESIGF-OH). Like L. splendida, L. rothii has reduced the smooth muscle potency of caerulein by replacing it with caerulein 1.2. Rothein 1 is a lymphocyte proliferator acting via CCK2R. Activity testing and 2D NMR spectra of rothein 1 and some synthetic modifications indicate that both hydrophobic and hydrophilic interactions between rothein 1 and CCK2R are important.  相似文献   
107.
Low-income urban whites in the United States have largely gone unexamined in health disparities research. In this study, we explored cancer prevention behaviors in this population. We compared data on whites with low socioeconomic status (SES) from the 2003 Exploring Health Disparities in Integrated Communities Study in Southwest Baltimore, Maryland (EHDIC-SWB) with nationally representative data for low SES white respondents from the 2003 National Health Interview Survey (NHIS). Rates for health behaviors and health indicators for whites from the EHDIC-SWB study as compared to NHIS prevalence estimates were as follows: current cigarette smoking, 59% (31% nationally); current regular drinking, 5% (5% nationally); overweight, 26% (32% nationally); obesity, 30% (22% nationally); mammography in the past 2 years, 50% (57% nationally); Pap smear in the past 2 years, 64% (68% nationally); screening for colon cancer in the past 2 years, 41% (30% nationally); and fair or poor self-reported health, 37% (22% nationally). Several cancer prevention behaviors and health indicators for white EHDIC-SWB respondents were far from the Healthy People 2010 objectives. This study provides rare estimates of cancer-related health and health care measures in an understudied population in the United States. Findings illustrate the need for further examination of health behaviors in low SES white urban populations who may share health risks with their poor minority urban counterparts.  相似文献   
108.

Background  

Shortage of human resources is a major problem facing Malawi, where more than 50% of the population lives in rural areas. Most of the district health services are provided by clinical health officers specially trained to provide services that would normally be provided by fully qualified doctors or specialists. As this cadre and the cadre of enrolled nurses are the mainstay of the Malawian health service at the district level, it is important that they are supported and motivated to deliver a good standard of service to the population. This study explores how these cadres are managed and motivated and the impact this has on their performance.  相似文献   
109.
Communication abnormalities are hallmark features of schizophrenia. Despite the prevalence and persistence of these symptoms, little is known about their functional implications. In this study, we examined, in a sample of chronically institutionalized schizophrenia patients (N=317), whether two types of communication abnormalities (i.e., verbal underproductivity and disconnected speech) had differential relationships with social and adaptive outcomes. Baseline ratings of verbal underproductivity, disconnected speech, global cognitive performance, and clinical symptoms, were entered into stepwise regression analyses to examine their relationship with 2.5 year social and adaptive outcomes. At baseline, disconnected speech was significantly associated with socially impolite behavior, while verbal underproductivity was associated with social disengagement and impaired friendships. Both types of communication abnormalities were significantly associated with other types of social skills. Verbal underproductivity predicted follow-up social skills, social engagement, and friendships, accounting for more variance than. cognition or symptoms. In contrast to social outcomes, adaptive outcomes were predicted by baseline neurocognition and clinical symptoms, but not communication abnormalities. These findings provide evidence for specific relationships of communication disorder subtypes with diverse impairments in social functions. In this chronically institutionalized sample, communication disorder was a stronger predictor of social, but not adaptive, outcomes than neurocognition or clinical symptoms.  相似文献   
110.
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