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   46999篇
  免费   3389篇
  国内免费   163篇
耳鼻咽喉   486篇
儿科学   1024篇
妇产科学   925篇
基础医学   5943篇
口腔科学   1159篇
临床医学   4956篇
内科学   10062篇
皮肤病学   523篇
神经病学   3885篇
特种医学   1529篇
外国民族医学   1篇
外科学   7791篇
综合类   694篇
一般理论   33篇
预防医学   3993篇
眼科学   1284篇
药学   3100篇
中国医学   43篇
肿瘤学   3120篇
  2022年   357篇
  2021年   834篇
  2020年   500篇
  2019年   742篇
  2018年   884篇
  2017年   618篇
  2016年   725篇
  2015年   875篇
  2014年   1265篇
  2013年   1922篇
  2012年   2770篇
  2011年   2922篇
  2010年   1634篇
  2009年   1528篇
  2008年   2633篇
  2007年   2677篇
  2006年   2692篇
  2005年   2906篇
  2004年   2789篇
  2003年   2562篇
  2002年   2418篇
  2001年   583篇
  2000年   499篇
  1999年   625篇
  1998年   637篇
  1997年   495篇
  1996年   442篇
  1995年   416篇
  1994年   362篇
  1993年   339篇
  1992年   444篇
  1991年   407篇
  1990年   374篇
  1989年   339篇
  1988年   332篇
  1987年   338篇
  1986年   350篇
  1985年   354篇
  1984年   396篇
  1983年   405篇
  1982年   459篇
  1981年   426篇
  1980年   378篇
  1979年   286篇
  1978年   323篇
  1977年   302篇
  1976年   293篇
  1975年   240篇
  1974年   239篇
  1973年   249篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.  相似文献   
4.
5.
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).

Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.

Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).

Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).

Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.

Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED.  相似文献   
6.
7.
An essential piece of anesthesiologist training is attending resident feedback sessions. Yet, few attending anesthesiologists have formal teaching education and little time to acquire it. In this field experiment, attending physicians were randomly assigned to a control group or to receive 30 minutes of feedback training inspired by Implicit Person Theory (IPT). As such, IPT training encouraged physicians to praise process-oriented learning while discouraging performance-oriented mindsets. Attending physicians then observed residents participate in a human patient simulation (HPS) activity and provided residents with feedback. Content and statistical analyses revealed trained attending physicians praised learning goals and challenged performance goals more often than untrained physicians during feedback sessions. Thus, the training provides a rapid method of enhancing the quality of attending physicians’ training communication.  相似文献   
8.
The Impella 5.0, a percutaneously inserted left ventricular assist device, has been used to support patients who have severe heart failure or who are undergoing high-risk percutaneous coronary intervention. We report our surgical placement of the Impella 5.0, through a graft sewn to the aorta, to unload the left ventricle of a 59-year-old man who was undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy shock. The patient underwent successful placement of a long-term left ventricular assist device before his discharge from the hospital. The versatility of the Impella 5.0 is exemplified in this patient who was successfully bridged to long-term support.  相似文献   
9.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
10.
ABSTRACT

A monocausal bacteriological understanding of infectious disease orients tuberculosis control efforts towards antimicrobial interventions. A bias towards technological solutions can leave multistranded public health and social interventions largely neglected. In the context of globalising biomedical approaches to infectious disease control, this ethnography-inspired review article reflects upon the implementation of rapid diagnostic technology in low- and middle-income countries. Fieldwork observations in Vietnam provided a stimulus for a critical review of the global rollout of tuberculosis diagnostic technology. To address local needs in tuberculosis control, health managers in resource-poor settings are readily cooperating with international donors to deploy novel diagnostic technologies throughout national tuberculosis programme facilities. Increasing investment in new diagnostic technologies is predicated on the supposition that these interventions will ameliorate disease outcomes. However, suboptimal treatment control persists even when accurate diagnostic technologies are available, suggesting that promotion of singular technological solutions can distract from addressing systemic change, without which disease susceptibility, propagation of infection, detection gaps, diagnostic delays, and treatment shortfalls persist.  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