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   235129篇
  免费   15553篇
  国内免费   1001篇
耳鼻咽喉   2558篇
儿科学   6120篇
妇产科学   4468篇
基础医学   29439篇
口腔科学   4364篇
临床医学   24064篇
内科学   49299篇
皮肤病学   3238篇
神经病学   23673篇
特种医学   10162篇
外国民族医学   13篇
外科学   37298篇
综合类   2552篇
现状与发展   1篇
一般理论   179篇
预防医学   16391篇
眼科学   5594篇
药学   15577篇
  1篇
中国医学   326篇
肿瘤学   16366篇
  2023年   1237篇
  2022年   859篇
  2021年   5269篇
  2020年   3080篇
  2019年   5109篇
  2018年   6103篇
  2017年   4489篇
  2016年   4904篇
  2015年   5799篇
  2014年   8440篇
  2013年   11363篇
  2012年   17455篇
  2011年   18188篇
  2010年   10158篇
  2009年   9407篇
  2008年   16002篇
  2007年   16820篇
  2006年   16364篇
  2005年   16234篇
  2004年   15259篇
  2003年   13949篇
  2002年   13316篇
  2001年   2071篇
  2000年   1538篇
  1999年   2098篇
  1998年   2808篇
  1997年   2195篇
  1996年   1560篇
  1995年   1724篇
  1994年   1498篇
  1993年   1469篇
  1992年   1005篇
  1991年   966篇
  1990年   805篇
  1989年   764篇
  1988年   706篇
  1987年   648篇
  1986年   663篇
  1985年   702篇
  1984年   911篇
  1983年   787篇
  1982年   1025篇
  1981年   957篇
  1980年   837篇
  1979年   459篇
  1978年   510篇
  1977年   441篇
  1976年   415篇
  1975年   309篇
  1974年   316篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
Moderate weight loss improves numerous risk factors for cardiometabolic disease; however, long-term weight loss maintenance (WLM) is often thwarted by metabolic adaptations that suppress energy expenditure and facilitate weight regain. Skeletal muscle has a prominent role in energy homeostasis; therefore, we investigated the effect of WLM and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity-prone rats, WLM reduced fat oxidative capacity and downregulated genes involved in fat metabolism. Interestingly, even after weight was regained, genes involved in fat metabolism were also reduced. We then subjected mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, to WLM and weight regain and found that mCK-hLPL attenuates weight regain by potentiating energy expenditure. Irrespective of genotype, weight regain suppressed dietary fat oxidation and downregulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain. In summary, these results suggest that skeletal muscle fat oxidation is reduced during WLM and regain, and therapies that improve skeletal muscle fat metabolism may attenuate rapid weight regain.  相似文献   
43.
44.
45.
Objectives:To reassess the long-term camouflage effects of resin infiltration (Icon, DMG, Hamburg, Germany) of white spot lesions (WSL) and sound adjacent enamel (SAE) achieved in a previous trial. The null hypothesis was tested that there were no significantly different CIE-L*a*b*-ΔE-values between WSL and SAE areas of assessment after at least 24 months (T24) compared to those at baseline (T0).Materials and Methods:Of twenty subjects who received previous resin infiltration treatment of nteeth = 111 nonrestored, noncavitated postorthodontic WSL after multibracket treatment during a randomized controlled trial and were contacted 20 months after baseline, eight subjects (trial teeth nteeth = 40; m/f ratio 1/7; age range (mean; SD) 12–17 [15.25; 2.12] years); response rate: 40%) were available for follow-up after at least 24 months (T24). CIE-L*a*b* differences between summarized color and lightness values (ΔEWSL/SAE) of WSL and SAE were assessed using a spectrophotometer and compared to baseline data assessed prior to infiltration (T0), and those after 6 (T6), and 12 (T12) months using paired t tests at a significance level of α = 5%.Results:T24 assessments were performed after a mean 33.86 (SD: 8.64; Min: 24; Max: 45) months following T0. Mean (SD) ΔEWSL/SAE units of available teeth were 8.76 (5.33) at baseline; 5.5 (2.75) at T6; 5.2 (2.41) at T12; and 5.57 (2.6) at T24. Comparisons of T6, T12, and T24 with T0 yielded highly significant differences, whereas T6–T24 and T12–T24 differences were found to be not significant.Conclusions:Assimilation of infiltrated WSL to the color of adjacent enamel by resin infiltration is considered to be suitable for the long-term improvement in the esthetic appearance of postorthodontic WSL.  相似文献   
46.
47.
48.
Clinical Epileptology - Schlafbezogene Atemstörungen sind eine Krankheitsentität mit unterschiedlichen Ursachen, die eine hohe Prävalenz hat. Sie ist Grundlage einer Vielzahl von...  相似文献   
49.
50.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  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