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   5646篇
  免费   574篇
  国内免费   17篇
耳鼻咽喉   51篇
儿科学   236篇
妇产科学   178篇
基础医学   727篇
口腔科学   132篇
临床医学   608篇
内科学   1180篇
皮肤病学   88篇
神经病学   554篇
特种医学   181篇
外科学   542篇
综合类   182篇
一般理论   8篇
预防医学   769篇
眼科学   108篇
药学   339篇
中国医学   1篇
肿瘤学   353篇
  2024年   9篇
  2023年   83篇
  2022年   111篇
  2021年   290篇
  2020年   165篇
  2019年   255篇
  2018年   285篇
  2017年   176篇
  2016年   162篇
  2015年   189篇
  2014年   309篇
  2013年   372篇
  2012年   533篇
  2011年   525篇
  2010年   270篇
  2009年   216篇
  2008年   342篇
  2007年   353篇
  2006年   298篇
  2005年   281篇
  2004年   225篇
  2003年   183篇
  2002年   195篇
  2001年   53篇
  2000年   37篇
  1999年   23篇
  1998年   19篇
  1997年   15篇
  1996年   13篇
  1995年   15篇
  1994年   11篇
  1993年   20篇
  1992年   10篇
  1991年   8篇
  1990年   16篇
  1989年   8篇
  1987年   9篇
  1986年   6篇
  1985年   11篇
  1984年   8篇
  1983年   9篇
  1982年   11篇
  1980年   8篇
  1975年   7篇
  1973年   9篇
  1972年   8篇
  1971年   6篇
  1969年   6篇
  1963年   5篇
  1936年   4篇
排序方式: 共有6237条查询结果,搜索用时 31 毫秒
1.
2.
Maternal and Child Health Journal - Background Prenatal substance use screening is recommended. The 4 P’s Plus screener includes questions on perceived problematic substance use in parents...  相似文献   
3.
4.
5.
6.
Motion is a major confound in diffusion‐weighted imaging (DWI) in the body, and it is a common cause of image artefacts. The effects are particularly severe in cardiac applications, due to the nonrigid cyclical deformation of the myocardium. Spin echo‐based DWI commonly employs gradient moment‐nulling techniques to desensitise the acquisition to velocity and acceleration, ie, nulling gradient moments up to the 2nd order (M2‐nulled). However, current M2‐nulled DWI scans are limited to encode diffusion along a single direction at a time. We propose a method for designing b‐tensors of arbitrary shapes, including planar, spherical, prolate and oblate tensors, while nulling gradient moments up to the 2nd order and beyond. The design strategy comprises initialising the diffusion encoding gradients in two encoding blocks about the refocusing pulse, followed by appropriate scaling and rotation, which further enables nulling undesired effects of concomitant gradients. Proof‐of‐concept assessment of in vivo mean diffusivity (MD) was performed using linear and spherical tensor encoding (LTE and STE, respectively) in the hearts of five healthy volunteers. The results of the M2‐nulled STE showed that (a) the sequence was robust to cardiac motion, and (b) MD was higher than that acquired using standard M2‐nulled LTE, where diffusion‐weighting was applied in three orthogonal directions, which may be attributed to the presence of restricted diffusion and microscopic diffusion anisotropy. Provided adequate signal‐to‐noise ratio, STE could significantly shorten estimation of MD compared with the conventional LTE approach. Importantly, our theoretical analysis and the proposed gradient waveform design may be useful in microstructure imaging beyond diffusion tensor imaging where the effects of motion must be suppressed.  相似文献   
7.
Abstract

The purpose of this study was to investigate the strength of the relationships between self-efficacy and (i) functional exercise capacity and (ii) physical activity in chronic obstructive pulmonary disease (COPD), and whether self-efficacy assessment type (i.e., COPD symptoms, exercise-task, exercise-barrier, general, falls) and physical activity assessment type (i.e., self-report vs. objective) are moderators. A systematic search of COPD and self-efficacy concepts was conducted using eight databases from inception to 23 January 2019. Studies were included if they provided correlation coefficients of the relationship between self-efficacy and functional exercise capacity or physical activity, were conducted in adults diagnosed with COPD, and were published in English-language journals. A total of 14 correlation coefficients were included in the self-efficacy and functional exercise capacity meta-analysis, and 16 in the self-efficacy and physical activity meta-analysis. Data were screened, reviewed, and extracted independently by two reviewers, with discrepancies resolved by a third reviewer. Stronger self-efficacy was associated with better functional exercise capacity (weighted r?=?0.38, 95%CI [0.25, 0.50]), and greater physical activity (weighted r?=?0.25, 95%CI [0.17, 0.34]). Exercise-task self-efficacy had the strongest relationship to functional exercise capacity (weighted r?=?0.64, 95% CI [0.51, 0.73]). For physical activity, the type of self-efficacy most strongly related was inconclusive. In COPD, self-efficacy has a relationship to functional exercise capacity and physical activity, the strength of which is influenced by the choice of self-efficacy measure. An understanding of these relationships will assist clinicians in selecting the self-efficacy measure most closely related to the outcome of interest.  相似文献   
8.
I discuss various viewpoints of physically disabled and nondisabled persons. I then question which views to preserve and which need to be changed as regards the subject of supervision of the physically disabled. I believe that illness and/or being physically disabled require different definitions and that for many physically disabled persons there is no either-or. In various theories it is asked how the physically disabled can be supported in their personal development, when it is maintained held that both disabled and non-disabled persons have the same mental and emotional conditions and requirements. The following theories will be considered: role theory, labeling theory, which holds to the idea of "self-fulfilling prophesy", the concept of the five pillars of identity, the expectations of self-effectiveness and of results and the theory of internal locus of control. It is a question of whether the physically disabled, like the nondisabled, should take the responsibility for their personal development upon themselves. In closing, I discuss where supervision can have a supportive effect in helping the physically disabled achieve greater personal development. Personal development improves the quality of life. Supervision for those who work with the physically disabled should contribute to reaching these goals.  相似文献   
9.
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