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   3231143篇
  免费   257461篇
  国内免费   6655篇
耳鼻咽喉   45959篇
儿科学   102113篇
妇产科学   89147篇
基础医学   452663篇
口腔科学   92450篇
临床医学   295416篇
内科学   631572篇
皮肤病学   69021篇
神经病学   271750篇
特种医学   126909篇
外国民族医学   1186篇
外科学   484686篇
综合类   78354篇
现状与发展   4篇
一般理论   1331篇
预防医学   262396篇
眼科学   76480篇
药学   236423篇
  5篇
中国医学   6553篇
肿瘤学   170841篇
  2018年   34554篇
  2017年   26518篇
  2016年   29459篇
  2015年   33289篇
  2014年   47935篇
  2013年   72587篇
  2012年   97921篇
  2011年   103510篇
  2010年   61065篇
  2009年   58440篇
  2008年   97277篇
  2007年   103256篇
  2006年   104285篇
  2005年   101467篇
  2004年   97339篇
  2003年   93645篇
  2002年   91635篇
  2001年   150830篇
  2000年   155547篇
  1999年   130988篇
  1998年   38390篇
  1997年   34787篇
  1996年   34448篇
  1995年   33030篇
  1994年   30724篇
  1993年   28791篇
  1992年   103535篇
  1991年   99536篇
  1990年   95864篇
  1989年   92159篇
  1988年   85471篇
  1987年   84071篇
  1986年   79249篇
  1985年   75720篇
  1984年   57797篇
  1983年   49245篇
  1982年   30168篇
  1981年   26834篇
  1979年   53484篇
  1978年   37747篇
  1977年   31653篇
  1976年   29755篇
  1975年   31000篇
  1974年   38124篇
  1973年   36431篇
  1972年   34180篇
  1971年   31435篇
  1970年   29733篇
  1969年   27663篇
  1968年   25612篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
23.

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   
24.
Introduction: Tamoxifen dominates the anti-estrogenic therapy in the early and metastatic breast cancer setting. Tamoxifen has a complex metabolism, being mainly metabolized by CYP2D6 into its 30–100 times more potent metabolite, endoxifen. Recently, a phase I study in which endoxifen as an orally z-endoxifen hydrochloride has been successfully evaluated.

Areas covered: the principal pharmacogenetic and non-genetic differences in the pharmacology of tamoxifen and endoxifen are evaluated. To this end, references from PubMed, Embase or Web of Science, among others, were reviewed As non-genetic factors, important differences and similarities such age, or adherence to tamoxifen therapy are comprehensively illustrated. Additionally, since CYP2D6 genotypes are considered the main limitation of tamoxifen, many studies have investigated the association between the worsened clinical outcomes in patients with non-functional CYP2D6 genotypes. In this review, an overview of the research on this field is presented. Also, a summary describing the literature about individualizing tamoxifen therapy with endoxifen concentrations and its limitations is listed.

Expert opinion: z-endoxifen hydrochloride is only investigated in the metastatic setting, still more research is required before its place in therapeutics is known. Similarly, monitoring tamoxifen efficacy based on endoxifen concentrations might not be overall recommended due to the limited evidence available.  相似文献   

25.
26.
27.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  相似文献   
28.
29.
ABSTRACT

Forest workers, including loggers, foresters, and wildland firefighters, are regularly exposed to some of the most fatal occupational environments in the United States. These hazardous work environments may become even more complex and dynamic when subject to bark beetle outbreaks that have resulted in significant tree mortality. The impacts of tree death from bark beetles are significant, with the cumulative 17-year (2000–2016) footprint for bark beetle caused tree mortality estimated at 54 million acres. However, how workers think about and act in these environments is understudied. This study, therefore, approaches the issue of beetle kill and forest worker safety by examining the perspectives or workers themselves. Its contribution is to leverage ethnographic research to provide insights that can generate new research questions, better inform outreach, and ultimately improve worker safety outcomes. The resulting insights show that beetle kill was understood by workers as a hazard that increased the complexity and dynamism of the work environment, making situational awareness both more necessary and more difficult to maintain. While much research about situational awareness focuses on hazardous situations, it is suggested that building adequate situational awareness should also include broader considerations of organizational communication, as well as training and experience considered over the course of entire careers.  相似文献   
30.
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