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   5752篇
  免费   533篇
  国内免费   9篇
耳鼻咽喉   72篇
儿科学   196篇
妇产科学   162篇
基础医学   811篇
口腔科学   57篇
临床医学   762篇
内科学   1003篇
皮肤病学   110篇
神经病学   649篇
特种医学   111篇
外科学   563篇
综合类   48篇
一般理论   6篇
预防医学   709篇
眼科学   325篇
药学   334篇
中国医学   3篇
肿瘤学   373篇
  2024年   23篇
  2023年   137篇
  2022年   187篇
  2021年   425篇
  2020年   268篇
  2019年   337篇
  2018年   333篇
  2017年   273篇
  2016年   289篇
  2015年   236篇
  2014年   320篇
  2013年   363篇
  2012年   465篇
  2011年   487篇
  2010年   234篇
  2009年   209篇
  2008年   296篇
  2007年   247篇
  2006年   226篇
  2005年   214篇
  2004年   165篇
  2003年   190篇
  2002年   158篇
  2001年   24篇
  2000年   10篇
  1999年   11篇
  1998年   33篇
  1997年   12篇
  1996年   12篇
  1995年   7篇
  1994年   7篇
  1993年   5篇
  1992年   4篇
  1991年   6篇
  1990年   7篇
  1989年   7篇
  1987年   7篇
  1986年   3篇
  1985年   6篇
  1984年   3篇
  1983年   5篇
  1982年   3篇
  1980年   4篇
  1979年   3篇
  1975年   2篇
  1973年   7篇
  1972年   4篇
  1970年   3篇
  1969年   2篇
  1967年   2篇
排序方式: 共有6294条查询结果,搜索用时 15 毫秒
51.
Purpose: To determine the impact of whole pelvic irradiation on the risk of PSA failure in prostate cancer patients, at high predicted risk for lymph node involvement, receiving definitive radiotherapy.

Materials and Methods: Between October 1987 and December 1995, 506 patients with clinically localized prostate cancer were treated with definitive radiotherapy at UCSF and affiliated institutions. Treatment consisted of 4-field whole pelvic irradiation followed by a prostate-only boost, or prostate-only treatment (median follow-up was 35 months and 30 months, respectively). PSA failure was defined as: 1. a PSA value ≥ 1 ng/ml; or 2. a PSA value that rose ≥ 0.5 ng/ml in ≤ 1 year posttreatment on two consecutive measurements, with the first rise defined as the time of failure. The calculated risk of lymph node positivity (%rLN+) was defined as (iPSA) + 10(GS-6), and high risk was defined as %rLN+ ≥ 15%. Univariate and multivariate analyses were performed.

Results: A total of 201 high-risk patients were identified. High-risk patients who received whole pelvic irradiation had significantly improved freedom from PSA failure compared to those who received prostate-only treatment (median PFS = 34.3 months vs. 21.0 months; p = 0.0001). Potential confounding variables, including initial PSA, Gleason score, T stage, radiation dose, year of treatment, use of three-dimensional (3D) conformal techniques, and use of hormone therapy, did not account for the observed difference in time to PSA failure. Multivariate analysis revealed type of radiation treatment to be the most significant independent predictor of outcome.

Conclusion: Whole pelvic radiotherapy significantly improves the PSA failure-free survival in patients with a high calculated risk of lymph node positivity.  相似文献   

52.
Krithika Rajagopalan  PhD    Linda Abetz  MA    Polyxane Mertzanis  MPH    Derek Espindle  MA    Carolyn Begley  OD  MS    Robin Chalmers  OD    Barbara Caffery  OD  MS    Christopher Snyder  OD  MS    J. Daniel Nelson  MD    Trefford Simpson  PhD    Timothy Edrington  OD  MS 《Value in health》2005,8(2):168-174
OBJECTIVE: The purpose of this study was to compare the discriminative properties of two generic health-related quality of life (QoL) instruments (SF-36 and EQ-5D) and a newly developed disease-specific patient-reported outcomes instrument (Impact of Dry Eye on Everyday Life (IDEEL)) to distinguish between different levels of dry eye severity. METHODS: Assessment of 210 people: 130 with non-Sjogren's Keratoconjunctivitis Sicca (non-SS KCS), 32 with Sj?gren's Syndrome (SS) and 48 controls; comparison of SF-36, EQ-5D, and IDEEL age-adjusted data by dry eye severity levels. Severity was assessed based on diagnosis (non-SS KCS, SS, control), patient-report (none, very mild, mild, moderate, severe, extremely severe) and clinician-report (none, mild, moderate, severe). RESULTS: Discriminative validity results were consistent for all instruments. Significant differences between severity levels were found with most SF-36 scales (P < 0.05), all EQ-5D scales (P < 0.05), and all IDEEL scales (P < 0.0001), except for Treatment Satisfaction. IDEEL scales consistently outperformed the generic QoL measures regardless of the severity criterion used. Most SF-36 scales outperformed the EQ-5D QoL scale, but the EQ-5D visual analog scale outperformed the SF-36 scales, except for General Health Perceptions. CONCLUSIONS: The disease-specific IDEEL scales are better able to discriminate between severity levels than the majority of the generic QoL scales. Preliminary evidence demonstrates that the IDEEL will be sensitive to QoL changes over time, although further testing in controlled longitudinal studies is needed.  相似文献   
53.
UK-427,857 (4, 4-difluoro-N-[(1S)-3-[exo-3-(3-isopropyl-5-methyl-4H-1,2,4-triazol-4-yl)-8-azabicyclo[3.2.1]oct-8-yl]-1-phenylpropyl]cyclohexanecarboxamide) is a novel CCR5 antagonist undergoing investigation for use in the treatment of human immunodeficiency virus (HIV) infection. Pharmacokinetic and metabolism studies have been performed in mouse, rat, dog, and human after single and multiple administration by oral and intravenous routes. The compound has physicochemical properties that are borderline for good pharmacokinetics, being moderately lipophilic (log D(7.4) 2.1) and basic (pK(a) 7.3), possessing a number of H-bonding functionalities, and with a molecular weight of 514. The compound was incompletely absorbed in rat (approximately 20-30%) but well absorbed in dog (>70%). Based on in vitro studies in Caco-2 cells, UK-427,857 has relatively poor membrane permeability, and transcellular flux is enhanced in the presence of inhibitors of P-glycoprotein. Further evidence for the involvement of P-glycoprotein in restricting the oral absorption of UK-427,857 was obtained in P-glycoprotein null mice (mdr1a/mdr1b knockout). In these animals, AUC after oral administration was 3-fold higher than in control animals. In oral dose escalation studies in humans, the compound demonstrated nonlinear pharmacokinetics, with increased dose-normalized exposure with increased dose size, consistent with saturation of P-glycoprotein. The oral dose-exposure relationship of UK-427,857 in humans was not reflected in either rat or dog. In animal species and humans, UK-427,857 undergoes some metabolism, with parent compound the major component present in the systemic circulation and excreta. Elimination of radioactive dose was primarily via the feces. In rat, parent compound was secreted via bile and directly into the gastrointestinal tract. Metabolites were products of oxidative metabolism and showed a high degree of structural consistency across species.  相似文献   
54.
55.
56.
57.
58.
59.
While virtual learning environments (VLE) can be used in medical education as stand-alone educational interventions, they can also be used in preparation for traditional “face-to-face” training sessions as part of a “flipped classroom” model. We sought to evaluate the introduction of this model in a single module on maxillofacial radiology from a course on trauma skills. Course delegates were randomised into two groups: one was given access to an e-learning resource (test group) and the other attended a traditional didactic lecture (control group). Knowledge and confidence were assessed before and after the course with a 20-question single-best-answer paper and a 10-situation 100 mm visual analogue scale (VAS) paper, respectively. All participants were then given free access to the VLE for 30 days and were invited to take part in an e-survey. Neither group showed improvements in the single-best-answer scores, but both groups showed comparable improvements in VAS (control: median (range) values improved from 40.8 (17.7–82.5) mm to 62.8 (35.3–88.7) mm, p = 0.001; test group: from 47.7 (10.9–58.1) mm to 60.5 (32.4–75.6) mm, p = 0.005). Half of the respondents stated that they preferred the “flipped classroom” approach, and 22/22 stated that they would be “likely” or “very likely” to use an e-learning resource with expanded content. The “flipped classroom” approach was well received and there were comparable improvements in confidence. As maxillofacial radiology lends itself to online instruction with its reliance on the recognition of patterns, and problem-based approach to learning, a piloted e-learning resource could be developed in this area.  相似文献   
60.
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