首页 | 官方网站   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   1484篇
  免费   81篇
  国内免费   35篇
医药卫生   1600篇
  2021年   19篇
  2020年   9篇
  2019年   16篇
  2018年   20篇
  2017年   13篇
  2016年   14篇
  2015年   25篇
  2014年   34篇
  2013年   36篇
  2012年   62篇
  2011年   66篇
  2010年   48篇
  2009年   72篇
  2008年   55篇
  2007年   77篇
  2006年   61篇
  2005年   63篇
  2004年   47篇
  2003年   40篇
  2002年   41篇
  2001年   57篇
  2000年   51篇
  1999年   48篇
  1998年   44篇
  1997年   44篇
  1996年   40篇
  1995年   26篇
  1994年   17篇
  1993年   19篇
  1992年   16篇
  1991年   21篇
  1990年   30篇
  1989年   38篇
  1988年   42篇
  1987年   36篇
  1986年   41篇
  1985年   21篇
  1984年   17篇
  1983年   14篇
  1982年   11篇
  1981年   11篇
  1979年   19篇
  1978年   12篇
  1977年   14篇
  1976年   13篇
  1975年   14篇
  1974年   10篇
  1973年   9篇
  1970年   7篇
  1969年   9篇
排序方式: 共有1600条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
16.
OBJECTIVES: This article examines the differences found between clientele with severe mental health problems and their key health workers in terms of assessing service users' needs in 6 Quebec service areas. METHOD: We questioned 165 pairs of users and staff, using the Camberwell Assessment of Needs questionnaire. The profile of serious and overall problems encountered by clientele from each of the sites was compared. RESULTS: The sites with the greatest degree of user-staff agreement in identifying problems were also the ones where users considered that local services best met their needs. CONCLUSIONS: The study demonstrated that, in needs assessment, major differences exist between the perceptions of users and their key workers in the various sites. These differences can be explained in part by users' individual characteristics, by types of needs, by local particularities, and by service use.  相似文献   
17.
A mutual symbiotic enhancement of growth of Porphyromonas gingivalis and Treponema denticola is described in this report. Brain heart infusion broth supplemented with vitamin K did not support the individual growth of P. gingivalis or T. denticola. However, when inoculated as a mixture, both bacterial species did grow significantly. The growth-stimulating factors produced by P. gingivalis and T. denticola were dialyzable and heat stable and were further identified as isobutyric acid and succinic acid, respectively. Since some forms of periodontal disease are associated with the presence, in affected sites, of high numbers of P. gingivalis and spirochetes, it is suggested that the bacterial interaction described in this report might be of utmost importance in the initiation and progression of the disease.  相似文献   
18.
19.
The aim of the study was to examine whether proteolytic artifacts, which result in a loss and poor resolution of protein bands, occur during sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis analysis of cellular proteins from selected proteolytic ( Porphyromonas gingivalis, Prevotella nigrescens and Treponema denticola ) and non-proteolytic ( Fusobacterium nudeatum ) bacteria. Conditions to limit or prevent proteolysis were also investigated. Bacterial cells were incubated in solubilizing buffer (SDS +β mercaptoethanol) at room temperature for various periods of time before boiling. A control assay consisted of trichloroacetic acid-treated bacterial cells. Cellular proteins were separated by electrophoresis and stained with Coomassie blue. Proteolysis occurred very rapidly in the case of P. gingivalis (<30 s), whereas a longer incubation time (>1 h) was required to observe similar effects in P. nigrescens and T. denticola. No proteolysis was observed for F. nudeatum. In all cases, heat (100°C) and low pH (<4) treatments of bacterial cells could avoid production of proteolytic artifacts. Incorporation of specific protease inhibitors before solubilization of bacteria could also prevent proteolysis. More particularly, N -α- p -tosyl- l -lysine chloromethyl ketone (TLCK), iodoacetamide and diisopropylfluorophosphate (50 mM) were highly efficient for P. gingivalis, P. nigrescens and T. denticola , respectively. When outer membranes of P. gingivalis were prepared in the presence of TLCK, numerous additional protein bands, not seen in the absence of TLCK, were detected. The present study suggests that specific protease inhibitors, effective in preventing proteolysis. should be identified and added during cell fractionation and protein purification procedures.  相似文献   
20.
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-23

京公网安备 11010802026262号