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   4129736篇
  免费   305579篇
  国内免费   10381篇
耳鼻咽喉   58140篇
儿科学   131772篇
妇产科学   112035篇
基础医学   576408篇
口腔科学   118323篇
临床医学   381566篇
内科学   800346篇
皮肤病学   92317篇
神经病学   344438篇
特种医学   160798篇
外国民族医学   1440篇
外科学   618135篇
综合类   91870篇
现状与发展   6篇
一般理论   1774篇
预防医学   330267篇
眼科学   95771篇
药学   305119篇
  11篇
中国医学   8044篇
肿瘤学   217116篇
  2018年   45138篇
  2017年   34682篇
  2016年   39454篇
  2015年   44568篇
  2014年   62573篇
  2013年   94731篇
  2012年   126233篇
  2011年   133780篇
  2010年   80288篇
  2009年   76690篇
  2008年   125413篇
  2007年   133280篇
  2006年   134704篇
  2005年   130263篇
  2004年   125540篇
  2003年   120795篇
  2002年   117534篇
  2001年   187774篇
  2000年   193162篇
  1999年   163939篇
  1998年   49159篇
  1997年   43813篇
  1996年   43332篇
  1995年   42045篇
  1994年   38989篇
  1993年   36478篇
  1992年   130124篇
  1991年   125889篇
  1990年   121658篇
  1989年   117562篇
  1988年   108658篇
  1987年   107014篇
  1986年   101100篇
  1985年   96873篇
  1984年   72913篇
  1983年   62242篇
  1982年   37618篇
  1981年   33830篇
  1979年   66930篇
  1978年   47386篇
  1977年   40183篇
  1976年   37603篇
  1975年   39728篇
  1974年   48128篇
  1973年   45941篇
  1972年   43223篇
  1971年   40017篇
  1970年   37415篇
  1969年   35382篇
  1968年   32517篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
36.
37.
38.

Background

Nursing Home Compare (NHC) ratings, created and maintained by Medicare, are used by both hospitals and consumers to aid in the skilled nursing facility (SNF) selection process. To date, no studies have linked NHC ratings to actual episode-based outcomes. The purpose of this study was to evaluate whether NHC ratings are valid predictors of 90-day complications, readmission, and bundle costs for patients discharged to an SNF after primary total joint arthroplasty (TJA).

Methods

All SNF-discharged primary TJA cases in 2017 at a multihospital academic health system were queried. Demographic, psychosocial, and clinical variables were manually extracted from the health record. Medicare NHC ratings were then collected for each SNF. For patients in the Medicare bundle, postacute and total bundle cost was extracted from claims.

Results

Four hundred eighty-eight patients were discharged to a total of 105 unique SNFs. In multivariate analysis, overall NHC rating was not predictive of 90-day readmission/major complications, >75th percentile postacute cost, or 90-day bundle cost exceeding the target price. SNF health inspection and quality measure ratings were also not predictive of 90-day readmission/major complications or bundle performance. A higher SNF staffing rating was independently associated with a decreased odds for >75th percentile 90-day postacute spend (odds ratio, 0.58; P = .01) and a 90-day bundle cost exceeding the target price (odds ratio = 0.69; P = .02) but was similarly not predictive of 90-day readmission/complications.

Conclusion

Results of our study suggest that Medicare's NHC tool is not a useful predictor of 90-day costs, complications, or readmissions for SNFs within our health system.  相似文献   
39.
Background & Aims: Impaired message-structure mapping results in deficits in both sentence production and comprehension in aphasia. Structural priming has been shown to facilitate syntactic production for persons with aphasia (PWA). However, it remains unknown if structural priming is also effective in sentence comprehension. We examined if PWA show preserved and lasting structural priming effects during interpretation of syntactically ambiguous sentences and if the priming effects occur independently of or in conjunction with lexical (verb) information.

Methods & Procedures: Eighteen PWA and 20 healthy older adults (HOA) completed a written sentence-picture matching task involving the interpretation of prepositional phrases (PP; the chef is poking the solider with an umbrella) that were ambiguous between high (verb modifier) and low attachment (object noun modifier). Only one interpretation was possible for prime sentences, while both interpretations were possible for target sentences. In Experiment 1, the target was presented immediately after the prime (0-lag). In Experiment 2, two filler items intervened between the prime and the target (2-lag). Within each experiment, the verb was repeated for half of the prime-target pairs, while different verbs were used for the other half. Participants’ off-line picture matching choices and response times were measured.

Results: After reading a prime sentence with a particular interpretation, HOA and PWA tended to interpret an ambiguous PP in a target sentence in the same way and with faster response times. Importantly, both groups continued to show this priming effect over a lag (Experiment 2), although the effect was not as reliable in response times. However, neither group showed lexical (verb-specific) boost on priming, deviating from robust lexical boost seen in the young adults of prior studies.

Conclusions: PWA demonstrate abstract (lexically-independent) structural priming in the absence of a lexically-specific boost. Abstract priming is preserved in aphasia, effectively facilitating not only immediate but also longer-lasting structure-message mapping during sentence comprehension.  相似文献   

40.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  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