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   1297777篇
  免费   95903篇
  国内免费   2040篇
耳鼻咽喉   18404篇
儿科学   42934篇
妇产科学   38284篇
基础医学   189737篇
口腔科学   35693篇
临床医学   110383篇
内科学   255865篇
皮肤病学   27135篇
神经病学   101200篇
特种医学   50899篇
外国民族医学   367篇
外科学   200828篇
综合类   26866篇
现状与发展   1篇
一般理论   359篇
预防医学   94632篇
眼科学   29866篇
药学   99300篇
  1篇
中国医学   2514篇
肿瘤学   70452篇
  2018年   12180篇
  2016年   10411篇
  2015年   12006篇
  2014年   16609篇
  2013年   25273篇
  2012年   34880篇
  2011年   37342篇
  2010年   21998篇
  2009年   20730篇
  2008年   36304篇
  2007年   39299篇
  2006年   39831篇
  2005年   39211篇
  2004年   37789篇
  2003年   36669篇
  2002年   36204篇
  2001年   58431篇
  2000年   59840篇
  1999年   50980篇
  1998年   14530篇
  1997年   13086篇
  1996年   13319篇
  1995年   12580篇
  1994年   11966篇
  1993年   11066篇
  1992年   41204篇
  1991年   40561篇
  1990年   40069篇
  1989年   38885篇
  1988年   36276篇
  1987年   35514篇
  1986年   33883篇
  1985年   32331篇
  1984年   24111篇
  1983年   21013篇
  1982年   12597篇
  1981年   11144篇
  1979年   22768篇
  1978年   16033篇
  1977年   13878篇
  1976年   13077篇
  1975年   14322篇
  1974年   16804篇
  1973年   16169篇
  1972年   15391篇
  1971年   14304篇
  1970年   13268篇
  1969年   12805篇
  1968年   12017篇
  1967年   10519篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
151.
Background and Aims: Gastric antral vascular ectasia (GAVE) is commonly found in patients with cirrhosis, but it is also associated with other diseases in the absence of cirrhosis. Whether GAVE confers a different severity of gastrointestinal (GI) bleeding between patients with and without cirrhosis remains unknown. We aim to examine whether there is a difference in clinically significant GI bleeding due to GAVE in patients with or without cirrhosis. Methods: This is a retrospective case-control study of patients who were diagnosed with GAVE between January 2000 and June 2014. Patients were categorized into cirrhosis and noncirrhosis groups, and those with an additional GI bleeding source were excluded. Univariate comparisons and multivariable models were constructed using logistic regression. Results: In total, 110 patients diagnosed with GAVE on esophagogastroduodenoscopy (EGD) were included in our analysis; 84 patients had cirrhosis (76.4%) and 26 (23.6%) did not. Active GI bleeding was more prevalent in patients without cirrhosis (63.4% vs. 32.1%, p=0.003) despite similar indications for EGD, and endoscopic treatment with argon plasma coagulation (APC) was required more often in this group, approaching statistical significance (27% vs. 10.7%, p=0.056). There was no difference in bleeding severity, as evidenced by similar re-bleeding rates, surgery, or death attributed to uncontrolled bleeding. The strongest independent risk factor for GI bleeding was the absence of cirrhosis (odds ratio (OR): 5.151 (95% confidence interval (CI): 1.08-24.48, p=0.039). Conclusions: Patients with GAVE in the absence of cirrhosis are at higher risk for active GI bleeding and require more frequent endoscopic treatment than similar patients with cirrhosis. It may be worthwhile to treat GAVE in this population even in the absence of active bleeding.  相似文献   
152.
153.
154.
Health care expenditure in Germany shows clear regional differences. Such geographic variations are often seen as an indicator for inefficiency. With its homogeneous health care system, low co‐payments and uniform prices, Germany is a particularly suited example to analyse regional variations. We use data for the year 2011 on expenditure, utilization of health services and state of health in Germany's statutory health insurance system. This data, which originate from a variety of administrative sources and cover about 90% of the population, are enriched with a wealth of socio‐economic variables, data on pollutants, prices and individual preferences. State of health and demography explains 55% of the differences as measured by the standard deviation while all control variables account for a total of 72% of the differences at county level. With other measures of variation, we can account for an even greater proportion. A higher proportion of variation than usually supposed can thus be explained. Whilst this study cannot quantify inefficiencies, our results contradict the thesis that regional variations reflect inefficiency. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
155.
156.
157.
158.
159.

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   
160.

Background

Inflammation and infections have been associated with prostate cancer progression. We assessed whether elevated serum cytokines or T. vaginalis seropositivity at the time of diagnosis was associated with higher grade or lethal prostate cancer.

Patients and Methods

Men with localized or metastatic prostate cancer were included in this study. Cytokine serum levels including interleukin (IL)-1α, IL-1β, IL-2, IL-6, IL-8, monocyte chemotactic protein 1 (CCL-2), tumor necrosis factor α, and growth-regulated oncogene α (CXCL-1) using a multiplex enzyme-linked immunosorbent assay and T. vaginalis serology were measured in blood samples at diagnosis.

Results

A total of 324 patients were identified at time of localized disease and 118 at time of metastatic disease. Of the 189 patients with localized disease and clinical follow-up data (median, 73 months), 28 developed lethal disease. There was no association between circulating cytokine levels above median concentrations nor T. vaginalis seropositivity and risk of intermediate- to high-risk or lethal prostate cancer.

Conclusion

Higher levels of serum cytokine levels and T. vaginalis seropositivity at diagnosis are not associated with high-grade or lethal prostate cancer and do not aid risk stratification of localized prostate cancer.  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