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   39729篇
  免费   2436篇
  国内免费   114篇
耳鼻咽喉   346篇
儿科学   1308篇
妇产科学   1093篇
基础医学   5390篇
口腔科学   691篇
临床医学   6253篇
内科学   7373篇
皮肤病学   643篇
神经病学   3671篇
特种医学   843篇
外科学   3601篇
综合类   445篇
一般理论   58篇
预防医学   4868篇
眼科学   478篇
药学   2384篇
中国医学   73篇
肿瘤学   2761篇
  2023年   223篇
  2022年   404篇
  2021年   833篇
  2020年   496篇
  2019年   841篇
  2018年   964篇
  2017年   671篇
  2016年   711篇
  2015年   889篇
  2014年   1248篇
  2013年   1904篇
  2012年   2837篇
  2011年   3008篇
  2010年   1654篇
  2009年   1410篇
  2008年   2724篇
  2007年   2751篇
  2006年   2765篇
  2005年   2584篇
  2004年   2466篇
  2003年   2345篇
  2002年   2196篇
  2001年   329篇
  2000年   245篇
  1999年   380篇
  1998年   445篇
  1997年   402篇
  1996年   372篇
  1995年   307篇
  1994年   297篇
  1993年   289篇
  1992年   218篇
  1991年   189篇
  1990年   211篇
  1989年   176篇
  1988年   154篇
  1987年   153篇
  1986年   124篇
  1985年   150篇
  1984年   181篇
  1983年   173篇
  1982年   211篇
  1981年   187篇
  1980年   180篇
  1979年   118篇
  1978年   92篇
  1977年   99篇
  1976年   72篇
  1975年   69篇
  1974年   93篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
21.
22.
23.
Dietary supplementation with vitamin K(1), with vitamin D(3) and calcium or their combination, was examined in healthy older women during a 2-year, double-blind, placebo-controlled trial. Combined vitamin K with vitamin D plus calcium was associated with a modest but significant increase in BMC at the ultradistal radius but not at other sites in the hip or radius. INTRODUCTION: The putative beneficial role of high dietary vitamin K(1) (phylloquinone) on BMD and the possibility of interactive benefits with vitamin D were studied in a 2-year double-blind, placebo-controlled trial in healthy Scottish women > or =60 years of age. MATERIALS AND METHODS: Healthy, nonosteoporotic women (n = 244) were randomized to receive either (1) placebo, (2) 200 microg/day vitamin K(1), (3) 10 microg (400 IU) vitamin D(3) plus 1000 mg calcium/day, or (4) combined vitamins K(1) and D(3) plus calcium. Baseline and 6-month measurements included DXA bone mineral scans of the hip and wrist, markers of bone turnover, and vitamin status. Supplementation effects were tested using multivariate general linear modeling, with full adjustment for baseline and potential confounding variables. RESULTS: Significant bone mineral loss was seen only at the mid-distal radius but with no significant difference between groups. However, women who took combined vitamin K and vitamin D plus calcium showed a significant and sustained increase in both BMD and BMC at the site of the ultradistal radius. Serum status indicators responded significantly to respective supplementation with vitamins K and D. Over 2 years, serum vitamin K(1) increased by 157% (p < 0.001), the percentage of undercarboxylated osteocalcin (%GluOC) decreased by 51% (p < 0.001), serum 25-hydroxyvitamin D [25(OH)D] increased by 17% (p < 0.001), and PTH decreased by 11% (p = 0.049). CONCLUSIONS: These results provide evidence of a modest synergy in healthy older women from nutritionally relevant intakes of vitamin K(1) together with supplements of calcium plus moderate vitamin D(3) to enhance BMC at the ultradistal radius, a site consisting of principally trabecular bone. The substantial increase in gamma-carboxylation of osteocalcin by vitamin K may have long-term benefits and is potentially achievable by increased dietary intakes of vitamin K rather than by supplementation.  相似文献   
24.
Fear of falling, defined as a lack of self-confidence that one may avoid falls while doing everyday activities, may have serious consequences for elderly people. This article examines the prevalence, risk factors, and consequences of fear of falling in the elderly population; methods for assessing those fears; and suggests evidence-based interventions. Incorporating successful strategies into programs to reduce falling can result in improved patient outcomes as well as decreased healthcare utilization and costs.  相似文献   
25.
OBJECTIVES: To determine if experienced clinical educators (CEs) can improve their teaching by incorporating 4 literature-based teaching methods into their instruction. METHODS: We trained 7 experienced CEs on the teaching methods during a monthly faculty development program. Each CE recorded use of these methods during 10 months on a personal digital assistant. We compared the CEs' teaching evaluations with those of nonparticipating faculty by analysis of variance at baseline, during the study period, and for 1 year after the study. RESULTS: Reported use of 2 teaching methods (priming and feedback) increased significantly over use at baseline; use of 2 other methods (teaching in the patient's presence and 1-2 focal teaching points) remained constant. Scores on the CEs' teaching evaluations were significantly higher during the study period on 1 item, whereas the comparison group showed no changes. The changes persisted during the follow-up period. CEs reported that the teaching methods focused the learner and teacher, making subsequent encounters more productive. They also found that the act of entering data daily prompted them to reflect on their teaching. CONCLUSIONS: Experienced teachers can be persuaded to incorporate new methods into their daily teaching. Reflection on teaching is enhanced with group support and daily reminders. With these interventions, teaching effectiveness of these experienced educators improved.  相似文献   
26.
27.
28.
29.
30.
Abstract: Most individuals concerned about hereditary breast cancer risk will neither order nor benefit from genetic testing at the present time. Many will, however, seek information about their risk and testing. Risk assessment services, in addition to providing information about hereditary risk and genetic testing, need also to include assessment of non-hereditary risks, information about how to evaluate risks, early detection modalities, the etiology of cancer, and assistance in devising follow-up health care plans. Psychosocial factors, particularly those pertaining to the individual's past history with illness and beliefs about causes and prognosis, must be taken into account to provide relevant information that is understood. A case history with examples of some of the types of information that lead to informed consent in a cancer risk assessment setting is provided.  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