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   23029篇
  免费   2977篇
  国内免费   307篇
耳鼻咽喉   169篇
儿科学   903篇
妇产科学   216篇
基础医学   2287篇
口腔科学   1715篇
临床医学   1583篇
内科学   4575篇
皮肤病学   691篇
神经病学   1938篇
特种医学   347篇
外国民族医学   3篇
外科学   1711篇
综合类   1838篇
现状与发展   6篇
预防医学   4123篇
眼科学   552篇
药学   922篇
  5篇
中国医学   628篇
肿瘤学   2101篇
  2024年   14篇
  2023年   504篇
  2022年   587篇
  2021年   1164篇
  2020年   1121篇
  2019年   1076篇
  2018年   1072篇
  2017年   1005篇
  2016年   956篇
  2015年   973篇
  2014年   1422篇
  2013年   1846篇
  2012年   1106篇
  2011年   1324篇
  2010年   1049篇
  2009年   1078篇
  2008年   1111篇
  2007年   1028篇
  2006年   950篇
  2005年   780篇
  2004年   747篇
  2003年   711篇
  2002年   658篇
  2001年   523篇
  2000年   324篇
  1999年   280篇
  1998年   254篇
  1997年   290篇
  1996年   253篇
  1995年   251篇
  1994年   212篇
  1993年   180篇
  1992年   193篇
  1991年   183篇
  1990年   155篇
  1989年   145篇
  1988年   120篇
  1987年   102篇
  1986年   108篇
  1985年   83篇
  1984年   57篇
  1983年   61篇
  1982年   46篇
  1981年   45篇
  1980年   43篇
  1979年   25篇
  1978年   18篇
  1977年   24篇
  1976年   16篇
  1974年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
BackgroundRecent guidelines for the treatment of moderate or severe ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) have changed. This study assessed the real-world impact of changing guidelines on the management of IMR during CABG over time. We hypothesized that the utilization of mitral valve repair for IMR would decrease over time, whereas mitral valve replacement for severe IMR would increase.MethodsPatients undergoing CABG in a statewide collaborative database (2011-2020) were stratified by severity of IMR. Trends in mitral valve repair or replacement were evaluated. To account for differences of the patients, propensity score–matched analyses were used to compare patients with and without mitral intervention.ResultsA total of 11,676 patients met inclusion criteria, including 1355 (11.6%) with moderate IMR and 390 (3.3%) with severe IMR. The proportion of patients undergoing mitral intervention for moderate IMR decreased over time (2011, 17.7%; 2020, 7.5%; Ptrend = .001), whereas mitral replacement for severe IMR remained stable (2011, 11.1%; 2020, 13.3%; Ptrend = .14). Major morbidity was higher for patients with moderate IMR who underwent mitral intervention (29.1% vs 19.9%; P = .005). In a propensity analysis of 249 well-matched pairs, there was no difference in major morbidity (29.3% with mitral intervention vs 23.7% without; P = .16) or operative mortality (1.2% vs 2.4%; P = .5).ConclusionsConsistent with recent guideline updates, patients with moderate IMR were less likely to undergo mitral repair. However, the rate of replacement for severe IMR did not change. Mitral intervention during CABG did not increase operative mortality or morbidity.  相似文献   
4.
5.
PurposeAccording to the social determinants of health framework, income inequality is a potential risk factor for adverse mental health. However, few studies have explored the mechanisms suspected to mediate this relationship. The current study addresses this gap through a mediation analysis to determine if social support and community engagement act as mediators linking neighbourhood income inequality to maternal anxiety and depressive symptoms within a cohort of new mothers living in the City of Calgary, Canada.MethodsData collected at three years postpartum from mothers belonging to the All Our Families (AOF) cohort were used in the current study. Maternal data were collected between 2012 and 2015 and linked to neighbourhood socioeconomic data from the 2006 Canadian Census. Income inequality was measured using Gini coefficients derived from 2006 after-tax census data. Generalized structural equation models were used to quantify the associations between income inequality and mental health symptoms, and to assess the potential direct and indirect mediating effects of maternal social support and community engagement.ResultsIncome inequality was not significantly associated with higher depressive symptoms (β = 0.32, 95%CI = −0.067, 0.70), anxiety symptoms (β = 0.11, 95%CI = −0.39, 0.60), or lower social support. Income inequality was not associated with community engagement. For the depression models, higher social support was significantly associated with lower depressive symptoms (β = −0.13, 95%CI = −0.15, −0.097), while community engagement was not significantly associated with depressive symptoms (β = 0.059, 95%CI = −0.15, 0.27). Similarly, for the anxiety models, lower anxiety symptoms were significantly associated with higher levels of social support (β = −0.17, 95%CI = −0.20, −0.13) but not with higher levels of community engagement (β = 0.14, 95%CI = −0.14, 0.41).ConclusionThe current study did not find clear evidence for social support or community engagement mediating the relationship between neighbourhood income inequality and maternal mental health. Future investigations should employ a broader longitudinal approach to capture changes in income inequality, potential mediators, and mental health symptomatology over time.  相似文献   
6.
目的 采用网状Meta分析方法,评价针刺、火针、艾灸等不同针灸疗法对寻常痤疮(acne vulgaris, AC)临床有效率及复发率的影响。方法 计算机检索PubMed、Embase、Cochrane、Web of Science、CINAHL、中国知网(China National Knowledge Infrastructure, CNKI)、万方数据库(WanFang Data)、中国生物医学文献数据库(China Biology Medicine disc, CBM)和维普中文期刊服务平台(VIP Database),搜集针灸疗法治疗寻常痤疮的随机对照试验(randomized controlled trail, RCT),检索时间均为建库至2021年3月,文献筛选、资料提取及偏倚风险评价均由两名研究者独立进行。数据分析使用Stata16.0软件。结果 纳入42项RCT,共3911例寻常痤疮患者。数据分析结果显示,临床总有效率:艾灸、放血、放血+穴位注射、放血+针刺、火针优于西药(P<0.05),放血、放血+穴位注射、放血+针刺、火针、穴位埋线优于针刺疗法(P<0.05),放血+针刺疗法优于自血疗法(P<0.05),累计排序概率曲线下面积(surface under the cumulative,SUCRA)显示放血+针刺治疗寻常痤疮总有效率最高;复发率:放血疗法+穴位注射优于电针(P<0.05),SUCRA结果显示针刺+自血疗法治疗寻常痤疮复发率最低。结论 放血联合针刺疗法在提高总有效率上具有最好的疗效,针刺联合自血疗法可有效降低复发率,受纳入研究所限,以上结论尚需更多大样本、高质量RCT进一步验证。  相似文献   
7.
8.
以“七麦数据”网站收录的中医移动医疗App作为研究对象,采用网络调查法和文献分析法,根据“七麦数据”对移动医疗App的分类,结合中医移动医疗App的信息服务内容和特点,将筛选出的中医移动医疗App划分为医疗健康类、中医养生类、知识传播类、全面综合类,并根据“七麦数据”网站中对各类中医移动医疗App的打分及累计下载量筛选出最具代表性的12款中医移动医疗App,从全面性、人性化、安全性、实用性4个一级指标和40个二级指标对其信息服务现状进行评价,指出当前中医移动医疗App信息服务存在的问题并提出建议。  相似文献   
9.
10.
BackgroundIn order to avoid excessive treatment of thyroid nodules in the clinic, it is necessary to find a simple and practical analysis method to comprehensively and accurately reflect benign or malignant thyroid nodules. This study aimed to construct and validate a comprehensive and reliable network-based predictive model using a variety of imaging and laboratory criteria for thyroid nodules to stratify the risk of malignancy prior to surgery.MethodsWe retrospectively analyzed data from patients who underwent surgical treatment for thyroid nodules at the Thyroid and Breast Diagnosis and Treatment Center of Weifang Hospital of Traditional Chinese Medicine between January 2018 and December 2020. Binary logical regression analysis was performed to predict whether nodules were malignant or benign. The developmental dataset included 457 patients (January 2018–December 2020). The validation set included separate data points (n = 225, January 2018–December 2020).ResultsIn this study, criteria that showed significant predictive value for malignant nodules included TI-RADS: 4b (p = 0.065); Bethesda IV, Bethesda V, Bethesda VI (P < 0.0001); BRAFV600E mutation (P < 0.0001); Calcitonin>5 pg/ml (p = 0.0037); and FNA-Tg>30 ng/ml (p = 0.0003). A 10-grade risk scoring system was developed. The risk of malignancy risk ranged from 2.06% to 100% and was positively associated with increasing risk grade. The areas under the receiver-operating characteristic curve of the development and validation sets were 0.972 and 0.946, respectively.ConclusionA simple, comprehensive and reliable web-based predictive model was designed using a variety of imaging and laboratory criteria to stratify thyroid nodules by probability of malignancy.  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