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   1371091篇
  免费   117532篇
  国内免费   8676篇
耳鼻咽喉   16994篇
儿科学   43388篇
妇产科学   36890篇
基础医学   187209篇
口腔科学   36825篇
临床医学   125801篇
内科学   282684篇
皮肤病学   32296篇
神经病学   111888篇
特种医学   56534篇
外国民族医学   293篇
外科学   213118篇
综合类   39090篇
现状与发展   8篇
一般理论   418篇
预防医学   109434篇
眼科学   28911篇
药学   97665篇
  49篇
中国医学   4325篇
肿瘤学   73479篇
  2018年   14409篇
  2017年   11722篇
  2016年   13760篇
  2015年   15947篇
  2014年   22122篇
  2013年   31840篇
  2012年   39198篇
  2011年   42092篇
  2010年   26790篇
  2009年   25865篇
  2008年   38566篇
  2007年   40925篇
  2006年   41958篇
  2005年   40226篇
  2004年   37797篇
  2003年   36795篇
  2002年   34664篇
  2001年   66675篇
  2000年   68522篇
  1999年   57175篇
  1998年   17082篇
  1997年   15425篇
  1996年   16283篇
  1995年   16478篇
  1994年   15322篇
  1993年   14270篇
  1992年   47236篇
  1991年   45866篇
  1990年   44078篇
  1989年   41883篇
  1988年   38837篇
  1987年   38154篇
  1986年   35912篇
  1985年   34678篇
  1984年   26389篇
  1983年   22124篇
  1982年   13860篇
  1981年   12462篇
  1980年   11723篇
  1979年   23552篇
  1978年   17072篇
  1977年   14385篇
  1976年   13182篇
  1975年   13722篇
  1974年   16093篇
  1973年   15396篇
  1972年   14173篇
  1971年   13036篇
  1970年   11880篇
  1969年   11101篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
12.
13.
Purpose

This paper describes the design of a theory-informed pragmatic intervention for adolescent perinatal depression in primary care in Nigeria.

Methods

We conducted Focus Group Discussions (FGDs) among 17 adolescent mothers and 25 maternal health care providers with experience in the receipt and provision of care for perinatal depression. The Consolidated Framework for Implementation Research (CFIR) was used to systematically examine the barriers and facilitators affecting adolescent mothers' use of an existing intervention package for depression. The Theoretical Domain Framework (TDF) and the Capability, Opportunity, Motivation, Behaviour (COM-B) model were used to analyze the results of the data across the five CFIR domains.

Results

FGD analysis revealed that care providers lacked knowledge on approaches to engage young mothers in treatment. Young mothers had poor treatment engagement, low social support, and little interest in parenting. A main characteristic of the newly designed intervention is the inclusion of age-appropriate psychoeducation supported with weekly mobile phone calls, to address treatment engagement and parenting behaviours of young mothers. Also in the outer setting, low social support from relatives was addressed with education, “as need arises” phone calls, and the involvement of "neighborhood mothers”. In the inner settings, care providers’ behaviour is addressed with training to increase their capacity to engage young mothers in treatment.

Conclusion

A theory-based approach helped develop an age-appropriate intervention package targeting depression and parenting skills deficit among perinatal adolescents in primary maternal care and in which a pragmatic use of mobile phone was key.

  相似文献   
14.
15.
16.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
17.
In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.  相似文献   
18.
19.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36 weeks gestational age)...  相似文献   
20.
Inappropriate use of acetaminophen (APAP) can lead to morbidity and mortality secondary to hepatic necrosis. Ginsenoside Rg1 is a major active ingredient in processed Panax ginseng, which is proved to elicit biological effects. We hypothesized the beneficial effect of Rg1 on APAP-mediated hepatotoxicity was through Nrf2/ARE pathway. The study was conducted in cells and mice, comparing the actions of Rg1. Rg1 significantly improved cell survival rates and promoted the expression of antioxidant proteins. Meanwhile, Rg1 reduced the excessive ROS and the occurrence of cell apoptosis, which were related to Nrf2/ARE pathway. Expression of Nrf2 has a certain cell specificity.

  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