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   1009篇
  免费   53篇
  国内免费   11篇
耳鼻咽喉   1篇
儿科学   29篇
妇产科学   9篇
基础医学   81篇
口腔科学   70篇
临床医学   91篇
内科学   326篇
皮肤病学   34篇
神经病学   41篇
特种医学   103篇
外科学   100篇
综合类   44篇
预防医学   55篇
眼科学   6篇
药学   33篇
肿瘤学   50篇
  2022年   7篇
  2021年   9篇
  2018年   9篇
  2017年   7篇
  2015年   13篇
  2014年   5篇
  2013年   19篇
  2012年   18篇
  2011年   28篇
  2010年   25篇
  2009年   23篇
  2008年   21篇
  2007年   47篇
  2006年   50篇
  2005年   35篇
  2004年   35篇
  2003年   34篇
  2002年   26篇
  2001年   30篇
  2000年   24篇
  1999年   30篇
  1998年   28篇
  1997年   33篇
  1996年   41篇
  1995年   21篇
  1994年   17篇
  1993年   22篇
  1992年   27篇
  1991年   24篇
  1990年   32篇
  1989年   35篇
  1988年   48篇
  1987年   37篇
  1986年   30篇
  1985年   20篇
  1984年   25篇
  1983年   18篇
  1982年   10篇
  1981年   15篇
  1980年   10篇
  1979年   5篇
  1978年   9篇
  1977年   11篇
  1976年   10篇
  1975年   6篇
  1974年   5篇
  1973年   8篇
  1972年   4篇
  1969年   4篇
  1968年   4篇
排序方式: 共有1073条查询结果,搜索用时 15 毫秒
1.
2.
3.
Only modest relationships have been found between cognitive functioning and treatment outcome; there is some indication of better prediction of within-treatment progress. The current study attempted to determine whether either cognitive or sociodemographic/alcohol-related variables were predictive of learning in educational treatment. Eighty-seven male alcoholics were exposed to one hour of instruction on the medical effects of alcohol. Sociodemographic, alcohol-related, and cognitive functioning measures were obtained at the outset of treatment. Knowledge was assessed 24 hours prior to and 24 hours and three weeks after the intervention. Statistically significant increases in knowledge were found both 24 hours and three weeks following the educational intervention; retention of information declined significantly from 24 hours to three weeks post-intervention. Discriminant function analyses using either seven cognitive variables or six alcohol-related/sociodemographic variables significantly discriminated between learners and nonlearners 24 hours after the intervention. The weighted composite of measures in each of the analyses was able to successfully differentiate learners from nonlearners in over 70% of the cases. The findings suggest that the clinician may be able to employ a limited number of variables to differentiate between patients who will and will not be able to acquire knowledge from educational interventions.  相似文献   
4.
OBJECTIVE--To describe the geographic distribution of measles cases in the United States by county for the 10-year period from 1980 through 1989. DESIGN--Ecological analysis of national measles surveillance data. METHODS--Measles cases reported to the Morbidity and Mortality Weekly Report from 1980 through 1989 were analyzed. Data from the 1980 and 1990 US censuses were used to produce demographic profiles for each of the 3137 countries. Outcome variables examined included mean annual incidence and number of years reporting measles, with use of Spearman's rank correlation coefficients to examine the association between the demographic and the two outcome variables. RESULTS--A total of 56,775 measles cases were reported during the decade. Of the nation's 3137 counties, 1690 (53.9%) did not report any cases; only 17 (0.5%) reported measles in all 10 years. Counties reporting measles more frequently during the decade had higher median populations, population densities, and percentage of black and Hispanic populations than those counties reporting less frequently. Population size, population density, and percentage of Hispanic population were associated with number of years reporting measles and mean annual measles incidence rate. Measles cases in counties reporting measles every year predominantly occurred in unvaccinated preschoolers; cases in counties reporting less frequently predominantly occurred in vaccinated school-aged children. CONCLUSIONS--This analysis illustrates the focal nature of measles in the United States during the past decade. Most counties have not reported a single case of measles during the entire decade, and only 17 counties reported measles every year. Targeted strategies are needed to improve age-appropriate immunization levels among preschool-aged children living in large inner-city areas.  相似文献   
5.
6.
7.
8.
Calcium channel blocker is useful for a variety of purposes and is effective for preventing hepatitis elicited by different inducers, suggesting its possible clinical application for treating hepatitis. The alpha1-subunit of the dihydropyridine-sensitive L-type calcium channel is a target of calcium channel blocker. For clinical application of calcium channel blocker, it is important to analyze the expression of the L-type calcium channel in the liver. However, the subtype of the L-type calcium channel alpha1-subunit expressed in the liver was not known. In the present study, the alpha1-subunit of the calcium channel expressed in human liver was systematically analyzed. The alpha1D subunit of the dihydropyridine-sensitive L-type voltage gated calcium channel is expressed relatively strongly in the liver and may play an important role in the liver.  相似文献   
9.
The glioma-polyposis syndrome   总被引:8,自引:0,他引:8  
  相似文献   
10.
A fibronectin substrate will significantly enhance the strength of endothelial cell attachment on grafts constructed of polyester elastomer (PE) and polytetrafluoroethylene (e-PTFE). This experiment was undertaken to determine the short-termin vivo stability of endothellum on these fibronectin coated surfaces. Eight mongrel dogs underwent bilateral carotid artery replacement with both graft materlals. All grafts were inoculated with 2,000 cells/mm2 using cultured autogenous venous endothelium labelled with Indium-111-oxine. The Indium-111 label in the grafts was measured immediately prior to implantation, after 1 hour ofin vivo perfusion, and at explantation after 24 hours. The percentage of inoculated cells attached to the grafts before perfusion was simillar for both materials, 93.3±3.0% versus 92.2±7.2%, for PE and e-PTFE respectively. All grafts were patent at one hour after implantation. PE grafts were found to have 93.8±3.9 % of the attached cells present at one hour while e-PTFE grafts had only 54.5 ± 10.8 % remaining, p<.001. After 24 hours, 5/8 (62.5%) e-PTFE grafts and 2/8 (25.0 %) PE grafts remained patent, p=.13. Of the patent grafts however, endothelial cell retention was still superior on the PE grafts with 78.0±0.6% of the attached cells remaining compared to only 24.5±6.1% on e-PTFE, p<.001. Occluded PE grafts had fewer cells remaining at 24 hours than patent ones, 78.0±0.6% versus 31.1±32.8%, respectively, p=.13. Histologically, patent PE grafts demonstrated nearly confluent endothelial monolayers while e-PTFE had patches of endothelial cells surrounded by, a platelet-fibrin carpet. We conclude that short-term patency appears to be determined by the extent of endothelial retention on PE but not e-PTFE.  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