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   124722篇
  免费   8397篇
  国内免费   539篇
耳鼻咽喉   1323篇
儿科学   3668篇
妇产科学   2093篇
基础医学   16543篇
口腔科学   2219篇
临床医学   12354篇
内科学   26465篇
皮肤病学   1489篇
神经病学   12091篇
特种医学   3845篇
外国民族医学   1篇
外科学   18027篇
综合类   1692篇
现状与发展   1篇
一般理论   156篇
预防医学   10956篇
眼科学   3363篇
药学   8817篇
  1篇
中国医学   278篇
肿瘤学   8276篇
  2023年   618篇
  2022年   1069篇
  2021年   2394篇
  2020年   1430篇
  2019年   2432篇
  2018年   2845篇
  2017年   2055篇
  2016年   2399篇
  2015年   2779篇
  2014年   3989篇
  2013年   5627篇
  2012年   8535篇
  2011年   9168篇
  2010年   5004篇
  2009年   4668篇
  2008年   8075篇
  2007年   8589篇
  2006年   8132篇
  2005年   8184篇
  2004年   7724篇
  2003年   7127篇
  2002年   6876篇
  2001年   1251篇
  2000年   943篇
  1999年   1283篇
  1998年   1469篇
  1997年   1242篇
  1996年   962篇
  1995年   956篇
  1994年   812篇
  1993年   796篇
  1992年   715篇
  1991年   645篇
  1990年   591篇
  1989年   539篇
  1988年   550篇
  1987年   517篇
  1986年   455篇
  1985年   529篇
  1984年   580篇
  1983年   542篇
  1982年   708篇
  1981年   620篇
  1980年   545篇
  1979年   401篇
  1978年   362篇
  1977年   374篇
  1976年   305篇
  1975年   285篇
  1974年   291篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Metabolomics may reveal novel insights into the etiology of prostate cancer, for which few risk factors are established. We investigated the association between patterns in baseline plasma metabolite profile and subsequent prostate cancer risk, using data from 3,057 matched case–control sets from the European Prospective Investigation into Cancer and Nutrition (EPIC). We measured 119 metabolite concentrations in plasma samples, collected on average 9.4 years before diagnosis, by mass spectrometry (AbsoluteIDQ p180 Kit, Biocrates Life Sciences AG). Metabolite patterns were identified using treelet transform, a statistical method for identification of groups of correlated metabolites. Associations of metabolite patterns with prostate cancer risk (OR1SD) were estimated by conditional logistic regression. Supplementary analyses were conducted for metabolite patterns derived using principal component analysis and for individual metabolites. Men with metabolite profiles characterized by higher concentrations of either phosphatidylcholines or hydroxysphingomyelins (OR1SD = 0.77, 95% confidence interval 0.66–0.89), acylcarnitines C18:1 and C18:2, glutamate, ornithine and taurine (OR1SD = 0.72, 0.57–0.90), or lysophosphatidylcholines (OR1SD = 0.81, 0.69–0.95) had lower risk of advanced stage prostate cancer at diagnosis, with no evidence of heterogeneity by follow-up time. Similar associations were observed for the two former patterns with aggressive disease risk (the more aggressive subset of advanced stage), while the latter pattern was inversely related to risk of prostate cancer death (OR1SD = 0.77, 0.61–0.96). No associations were observed for prostate cancer overall or less aggressive tumor subtypes. In conclusion, metabolite patterns may be related to lower risk of more aggressive prostate tumors and prostate cancer death, and might be relevant to etiology of advanced stage prostate cancer.  相似文献   
32.
33.
34.
35.
36.
37.
Paul Lombardo   《Radiography》2006,12(4):332-338
The Australian higher education system is in a state of great change. The Federal education minister, Dr Brendan Nelson, has indicated that he intends to continue introducing far-reaching reforms that will impact significantly on how universities conduct teaching and research. The future allocation of government funding for university programs, including those in medical radiation, will have a significant effect on how those programs are delivered and could even determine whether programs remain viable. There will be a financial imperative for academic departments to strengthen research activity and to obtain funding from non-government sources, such as full-fee paying students, in order to generate enough income to cover program delivery. Medical radiation education in Australia is also facing many other challenges. Some of these are longstanding, such as the high cost of medical radiation program delivery, poor levels of research activity and difficulty in recruiting and retaining academic staff. Other problems have arisen recently, such as increased competition for students and a critical shortage of available training placements in clinical practice. The aim of this paper is to raise and explore these issues from a university perspective.  相似文献   
38.
39.
Despite numerous studies of approach- and avoidant mindsets, relatively little research has addressed the impact of such motivational orientations on performance and emotion in a real-time, multi-task setting. A laboratory simulation is reported that examines the influence of an induced approach-centered, an avoidance-centered, and a “neutral” motivational mindset upon multiple aspects of task performance, self-regulatory cognition, and affect. Undergraduate females randomly assigned to one of three mindset conditions performed a simulated automobile drive across one practice and two experimental trials. Dependent measures included divided attention, behavioral indicators of driving “cautiousness” in relatively safe straight roadway sections as well as during more risk-filled driving, multiple aspects of self-regulatory thinking (including self-monitoring, intended effort, and self-administered consequences), and positive and negative affect. Results revealed that the avoidant mindset produced poorer executive attention (i.e., fewer correctly detected divided attention events), more “cautious” driving behavior and reduced performance variability (i.e., greater control) when driving on presumably safe, straight roadway sections, lower self-reports of intended effort, and greater negative affect relative to the approach mindset. Results are intepreted within a self-regulation-centered motivational framework. Implications of the multi-task simulation for the study of normal and disordered adjustment are considered.  相似文献   
40.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  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