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   894篇
  免费   36篇
  国内免费   17篇
耳鼻咽喉   1篇
儿科学   58篇
妇产科学   7篇
基础医学   69篇
口腔科学   51篇
临床医学   117篇
内科学   247篇
皮肤病学   12篇
神经病学   23篇
特种医学   145篇
外科学   70篇
综合类   45篇
一般理论   2篇
预防医学   39篇
眼科学   1篇
药学   27篇
中国医学   1篇
肿瘤学   32篇
  2021年   8篇
  2020年   6篇
  2019年   11篇
  2018年   12篇
  2017年   10篇
  2016年   7篇
  2015年   14篇
  2014年   22篇
  2013年   17篇
  2012年   22篇
  2011年   35篇
  2010年   33篇
  2009年   27篇
  2008年   23篇
  2007年   24篇
  2006年   29篇
  2005年   27篇
  2004年   30篇
  2003年   39篇
  2002年   28篇
  2001年   24篇
  2000年   21篇
  1999年   24篇
  1998年   30篇
  1997年   42篇
  1996年   48篇
  1995年   26篇
  1994年   30篇
  1993年   27篇
  1992年   9篇
  1991年   10篇
  1990年   12篇
  1989年   19篇
  1988年   20篇
  1987年   21篇
  1986年   29篇
  1985年   16篇
  1984年   9篇
  1983年   9篇
  1982年   17篇
  1981年   7篇
  1980年   9篇
  1979年   3篇
  1978年   15篇
  1977年   7篇
  1976年   12篇
  1975年   7篇
  1972年   3篇
  1971年   3篇
  1965年   3篇
排序方式: 共有947条查询结果,搜索用时 31 毫秒
1.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
2.
3.
4.
5.
6.
Experiments sought to determine the nature of the binding of milk proteins to hydroxyapatite (HA) and to saliva-coated hydroxyapatite (sHA), and to determine the effect of milk and casein on the adherence of Streptococcus mutans GS-5 to sHA. The binding of radiolabelled -casein to HA was reduced when incubated simultaneously with parotid saliva, and enhanced in the presence of milk. The binding of β- and κ-casein to HA was unaffected by the presence of parotid saliva and enhanced by the presence of milk. The in vitro bacterial adherence of Strep. mutans GS-5 to sHA beads was reduced when beads were coated with milk instead of buffer, or when bacteria were added to sHA in the presence of milk instead of buffer. Casein proteins (, β, κ) added to sHA simultaneously with bacteria inhibited the adherence of Strep. mutans GS-5 to sHA. κ-Casein, when bound to sHA, inhibited streptococcal adherence to sHA; - and β-casein, when bound to sHA, had no effect on streptococcal adherence. Fractionation of κ-casein by anion-exchange chromatography revealed the anti-adherence activity of κ-casein was mediated primarily by a 40,000 mol. wt. glycoprotein-containing fraction. These data show that milk, particularly κ-casein fractions, can modulate the adherence of Strep. mutans GS-5 to SHA surfaces in vitro.  相似文献   
7.
8.
Low-artifact intravascular devices: MR imaging evaluation   总被引:2,自引:0,他引:2  
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible.  相似文献   
9.
Variability of skin temperature in the waking monkey   总被引:3,自引:0,他引:3  
  相似文献   
10.
OBJECTIVE: To assess magnetic resonance imaging (MRI) findings in carpal tunnel syndrome (CTS) and to compare them with electrophysiological findings. METHODS: Routine motor and sensory nerve conduction examinations and needle EMG were performed in 42 hands of 22 patients, who were clinically diagnosed as having CTS in at least one wrist. RESULTS: Of 29 wrists with clinically and electrophysiologically confirmed CTS, MRI could detect abnormality in 18 wrists (62%). Median nerve was found to be abnormal in MRI in 1 of 2 wrists with suspected clinical symptoms and proven CTS by electrophysiological examination. MRI was abnormal in 1 of 4 wrists with normal clinical and electrophysiological examination. MRI was abnormal in 46, 7% of wrists with mild CTS, in 61.6% of moderate CTS and in 100% of severe CTS. Volar bulging of the flexor retinaculum was detected in a single wrist with severe CTS. Enlargement of median nerve was observed in 3 of 5 severe CTS. CONCLUSION: MRI could be useful in the diagnosis of unproven cases in CTS. It also provides anatomical information that correlate well with electrophysiological findings in regard of the severity of median nerve compression.  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