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   1295103篇
  免费   98820篇
  国内免费   1688篇
耳鼻咽喉   16644篇
儿科学   41806篇
妇产科学   35758篇
基础医学   193702篇
口腔科学   35313篇
临床医学   120934篇
内科学   253983篇
皮肤病学   27785篇
神经病学   105222篇
特种医学   47857篇
外国民族医学   265篇
外科学   184253篇
综合类   26153篇
现状与发展   4篇
一般理论   602篇
预防医学   107363篇
眼科学   28885篇
药学   94855篇
  6篇
中国医学   2125篇
肿瘤学   72096篇
  2019年   10683篇
  2018年   14420篇
  2017年   11003篇
  2016年   11948篇
  2015年   13802篇
  2014年   19162篇
  2013年   28959篇
  2012年   39972篇
  2011年   42464篇
  2010年   24480篇
  2009年   23548篇
  2008年   40035篇
  2007年   42829篇
  2006年   42288篇
  2005年   41349篇
  2004年   39668篇
  2003年   37958篇
  2002年   36719篇
  2001年   56358篇
  2000年   57340篇
  1999年   48430篇
  1998年   13767篇
  1997年   12547篇
  1996年   12959篇
  1995年   12178篇
  1994年   11354篇
  1993年   10622篇
  1992年   38389篇
  1991年   37836篇
  1990年   36581篇
  1989年   35385篇
  1988年   32831篇
  1987年   32162篇
  1986年   30647篇
  1985年   28905篇
  1984年   22071篇
  1983年   19329篇
  1982年   11529篇
  1979年   21016篇
  1978年   15493篇
  1977年   12895篇
  1976年   11919篇
  1975年   12889篇
  1974年   15654篇
  1973年   15416篇
  1972年   14562篇
  1971年   13590篇
  1970年   12817篇
  1969年   12083篇
  1968年   11249篇
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
41.
42.
43.
44.
45.
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR).  相似文献   
46.
47.
48.
49.
ContextIt is especially important that patients are well informed when making high-stakes, preference-sensitive decisions like those on the Physician Orders for Life-Sustaining Treatment (POLST) form. However, there is currently no way to easily evaluate whether patients understand key concepts when making these important decisions.ObjectivesTo develop a POLST knowledge survey.MethodsExpert (n = 62) ratings of key POLST facts were used to select items for a POLST knowledge survey. The survey was administered to nursing facility residents (n = 97) and surrogate decision-makers (n = 112). A subset (n = 135) were re-administered the survey after a standardized advance care planning discussion to assess the scale's responsiveness to change.ResultsThe 19-item survey demonstrated adequate reliability (α = 0.72.). Residents' scores (x = 11.4, standard deviation 3.3) were significantly lower than surrogate scores (x = 14.7, standard deviation 2.5) (P < 0.001). Scores for both groups increased significantly after administration of a standardized advance care planning discussion (P < 0.001). Although being a surrogate, age, race, education, cognitive functioning, and health literacy were significantly associated with higher POLST Knowledge Survey scores in univariate analyses, only being a surrogate (P < 0.001) and being white (P = 0.028) remained significantly associated with higher scores in multivariate analyses.ConclusionThe 19-item POLST Knowledge Survey demonstrated adequate reliability and responsiveness to change. Findings suggest the survey could be used to identify knowledge deficits and provide targeted education to ensure adequate understanding of key clinical decisions when completing POLST.  相似文献   
50.
Pharmaceutical Chemistry Journal - Three extracts were produced from the above-ground part of the meadowsweet Filipendula ulmaria (L.) Maxim. using water, 40% ethanol, and 70% ethanol. Comparative...  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