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   30598篇
  免费   2019篇
  国内免费   110篇
耳鼻咽喉   418篇
儿科学   700篇
妇产科学   537篇
基础医学   4273篇
口腔科学   1646篇
临床医学   2399篇
内科学   7257篇
皮肤病学   623篇
神经病学   2473篇
特种医学   836篇
外国民族医学   2篇
外科学   3805篇
综合类   278篇
一般理论   12篇
预防医学   3033篇
眼科学   599篇
药学   2052篇
中国医学   177篇
肿瘤学   1607篇
  2023年   239篇
  2022年   220篇
  2021年   852篇
  2020年   602篇
  2019年   824篇
  2018年   973篇
  2017年   655篇
  2016年   736篇
  2015年   881篇
  2014年   1206篇
  2013年   1498篇
  2012年   2369篇
  2011年   2463篇
  2010年   1350篇
  2009年   1143篇
  2008年   1901篇
  2007年   1955篇
  2006年   1871篇
  2005年   1687篇
  2004年   1520篇
  2003年   1357篇
  2002年   1324篇
  2001年   370篇
  2000年   336篇
  1999年   346篇
  1998年   229篇
  1997年   173篇
  1996年   162篇
  1995年   146篇
  1994年   150篇
  1993年   122篇
  1992年   179篇
  1991年   180篇
  1990年   154篇
  1989年   133篇
  1988年   138篇
  1987年   132篇
  1986年   110篇
  1985年   150篇
  1984年   135篇
  1983年   120篇
  1982年   122篇
  1981年   138篇
  1980年   126篇
  1979年   87篇
  1978年   92篇
  1977年   105篇
  1976年   76篇
  1975年   69篇
  1973年   60篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
European Journal of Clinical Microbiology & Infectious Diseases - Rapid immunochromatographic tests are frequently used to diagnose dengue due to their easy use, low cost, and fast response. A...  相似文献   
5.
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.  相似文献   
6.
7.
Bulletin of Environmental Contamination and Toxicology - This work describes the development of an analytical protocol combining cleanup by liquid–solid extraction and GC–MS for the...  相似文献   
8.
BackgroundAlthough there are robust data about the pathophysiology and prognostic implications of left ventricular (LV) systolic dysfunction in patients with acquired heart disease, similar prognostic data about LV systolic dysfunction are sparse in the tetralogy of Fallot (TOF) population. The purpose of this study was to perform a meta-analysis of all studies that assessed the relationship between LV ejection fraction (LVEF) and cardiovascular adverse events (CAEs) defined as death, aborted sudden death, or sustained ventricular tachycardia.MethodsWe used random-effects models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsOf the 1,809 citations, 7 studies with 2,854 patients (age 28 ± 4 years) were included. During 5.6 ± 3.4 years' follow-up, there were 82 deaths, 17 aborted sudden cardiac deaths, and 56 sustained ventricular tachycardia events. Overall, CAEs occurred in 5.1% (144 patients). As a continuous variable, LVEF was a predictor of CAE (HR 1.29, 95% CI, 1.09-1.53, P = 0.001) per 5% decrease in LVEF. Similarly, LVEF < 40% was also a predictor of CAE (HR 3.22, 95% CI, 2.16-4.80, P < 0.001).ConclusionsLV systolic dysfunction was an independent predictor of CAE, and we observed a 30% increase in the risk of CAE for every 5% decrease in LVEF, and a 3-fold increase in the risk of CAE in patients with LVEF <40% compared with other patients. These findings underscore the importance of incorporating LV systolic function in clinical risk stratification of patients with TOF and the need to explore new treatment options to address this problem.  相似文献   
9.
Background: Children with Developmental Coordination Disorder (DCD) have difficulties performing daily activities which reflects negatively on participation, impacting their lives.

Objectives: To examine the effects of the cognitive orientation to daily occupational performance Approach (CO-OP Approach) protocol on occupational performance and satisfaction of Brazilian children who have DCD; to examine whether children could transfer strategies and skills learned during CO-OP to untrained goals.

Methods: A pre-post group comparison design with eight boys aged 6–10 years old. Children participated in 12 CO-OP sessions with their parents twice a week, with an extra session added to the protocol for parents´ orientation. The Canadian Occupational Performance Measure and the Performance Quality Rating Scale were used as outcome measures. The study was registered by the United States Institutes of Health at ClinicalTrials.gov (NCT03112746).

Results: Intervention resulted in higher, clinically and statistically significant, occupational performance measures according to parents, children’s, and external evaluators’ perspectives. All children improved occupational performance on their selected goals and five children could transfer the ability to use cognitive strategies to tasks not addressed in therapy.

Conclusions: This study provides initial directions for future research to investigate the applicability and to implement CO-OP approach on pediatric settings in Brazil.  相似文献   

10.
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