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   2988篇
  免费   155篇
  国内免费   4篇
耳鼻咽喉   37篇
儿科学   156篇
妇产科学   118篇
基础医学   388篇
口腔科学   120篇
临床医学   339篇
内科学   529篇
皮肤病学   42篇
神经病学   290篇
特种医学   62篇
外科学   261篇
综合类   9篇
预防医学   325篇
眼科学   54篇
药学   224篇
中国医学   4篇
肿瘤学   189篇
  2023年   11篇
  2022年   13篇
  2021年   35篇
  2020年   34篇
  2019年   53篇
  2018年   52篇
  2017年   39篇
  2016年   68篇
  2015年   72篇
  2014年   94篇
  2013年   141篇
  2012年   195篇
  2011年   184篇
  2010年   119篇
  2009年   110篇
  2008年   183篇
  2007年   213篇
  2006年   191篇
  2005年   185篇
  2004年   158篇
  2003年   166篇
  2002年   144篇
  2001年   39篇
  2000年   39篇
  1999年   46篇
  1998年   37篇
  1997年   33篇
  1996年   40篇
  1995年   28篇
  1994年   26篇
  1993年   29篇
  1992年   27篇
  1991年   33篇
  1990年   33篇
  1989年   37篇
  1988年   24篇
  1987年   27篇
  1986年   20篇
  1985年   14篇
  1984年   12篇
  1983年   13篇
  1982年   11篇
  1981年   17篇
  1980年   12篇
  1979年   11篇
  1978年   9篇
  1977年   8篇
  1975年   9篇
  1974年   7篇
  1972年   8篇
排序方式: 共有3147条查询结果,搜索用时 203 毫秒
101.

Objective

The aim of this study was to evaluate the clinical retention of a one-step self-etching adhesive system (Xeno III) in Class V non-carious cervical lesions and the effect of restorative material and curing techniques on longevity of the restorations.

Materials and methods

A total of 139 Class V restorations were placed with the self-etching primer Xeno III and a resin composite (Tetric Ceram) or a poly-acid modified resin composite (Dyract AP) in non-carious cervical lesions without intentional enamel involvement. The materials were cured with a conventional continuous light, a soft-start or a pulse-delay curing mode. The restorations were evaluated at baseline, 6, 12, 18 and 24 months and then yearly during a 7 year follow-up with modified USPHS criteria. Dentine bonding efficiency was determined by the percentage of lost restorations.

Results

During the 7 years, 135 restorations could be evaluated. No post-operative sensitivity was reported by the participants. Overall relative cumulative loss rate frequencies for the adhesive system at 6 and 18 months and 7 years, independent of curing technique and restorative material, were 0.8%, 6.9% and 23.0%, respectively. The self-etching adhesive fulfilled at 18 months the full acceptance ADA criteria. Tetric Ceram showed at 7 years a 20.9% loss of retention and Dyract AP a 25.0% loss rate (Log rank p = 0.48). The loss rates for the 3 curing techniques: continuous, soft start and pulse delay were 17%, 27.9% and 24.4%, respectively (Log rank p = 0.52). No secondary caries was observed.

Significance

The single-step self-etching adhesive showed acceptable clinical long-time retention rates to dentine surfaces independent of restorative material and curing technique used.  相似文献   
102.
Journal of Neurology - Determining the cause of acute ischemic stroke is crucial for patient management, particularly for preventing future stroke. In recent years, carotid web (CW), a...  相似文献   
103.
104.

Introduction and hypothesis

We evaluated the effect of adding pelvic floor muscle training (PFMT) to a structured lifestyle advice program.

Methods

This was a single-blinded randomized trial of women with symptomatic pelvic organ prolapse (POP) stage?≥?II. Participants were randomized to a structured lifestyle advice program with or without PFMT. Both groups received similar lifestyle advice in six separate group sessions. The combined group performed group PFMT after an individual assessment. Primary outcome was a global improvement scale at six-month follow-up. Secondary outcomes were the global scale and objective POP at three-month follow-up, symptoms and quality of life including sexuality, at three and six-month follow-up. A clinically relevant change of symptoms was defined as ≥15 %.

Results

We included 109 women. Eighty-nine women (82 %) completed three months follow-up; 85 (78 %) completed six-month follow-up. At both follow-ups, significantly more women in the combined group reported improvement in the global scale. At the three-month follow-up, the combined group only had significant improvement of POP symptoms while only the lifestyle advice group had significant improvement of quality of life. Change in objective POP and sexuality was nonsignificant. The symptom score improved 17 % in the combined group and 14 % in the lifestyle advice group (P?=?0.57). Significantly more women in the lifestyle advice group had sought further treatment at the six-month follow-up.

Conclusion

Adding PFMT to a structured lifestyle advice program gave superior results in a global scale and for POP symptoms. Overall effect of either intervention barely reached clinical relevance.
  相似文献   
105.
Exclusive breastfeeding is recommended during the first 6 months of life; thereafter, continued breastfeeding along with nutritious complementary foods is recommended. Continued breastfeeding contributes a substantial proportion of nutrient needs and promotes healthy growth and development, but the quantity of breast milk consumed may be highly variable and little is known about the factors associated with breast milk intake after 6 months of age. The present study was conducted to assess factors associated with breast milk intake of Malawian infants at 9–10 months of age. Breast milk intake was measured using the dose‐to‐mother deuterium oxide dilution method in a subsample of 358 Malawian infants who were participating in a randomized controlled trial of lipid‐based nutrient supplements. Regression analysis was used to assess associations between breast milk intake and several maternal and infant variables. Mean (standard deviation) breast milk intake was 752 (244) g day–1. In multiple regression, breast milk intake was positively associated with infant weight (+62 g per kg body weight, P < 0.01) and maternal height (P < 0.01) and negatively associated with maternal education and age (P < 0.01). There was a non‐significant (P = 0.063) inverse association between energy from non‐breast milk sources and breast milk intake. In this rural Malawian population, infant weight is the main predictor of breast milk intake, even after the first 6 months of life.  相似文献   
106.
107.
Attention deficit hyperactivity disorder (ADHD) is a common developmental disorder. The present study tested the hypotheses that children with ADHD, particularly those exhibiting severe hyperactivity and impulsivity, have a different stress reaction (measured by salivary cortisol) during a dental recall visit and are more dentally anxious than children in a control group. Eighteen children with ADHD and a control group of 71 children, all 13 yr of age, underwent a clinical dental examination and completed the Corah Dental Anxiety Scale (CDAS). Four saliva samples were gathered for analysis of cortisol: one prior to dental examination, one after, and two the following morning. The subgroup ADHD with hyperactivity/impulsivity had statistically significantly lower cortisol levels than the control group 30 min after awakening. When cortisol values were plotted on a timeline, this subgroup always had lower cortisol concentrations than children in the control group. There was a significant correlation between CDAS scores and cortisol concentrations prior to the dental examination in both the ADHD and the control group. Behavioral expressions of anxiety in children with ADHD may be different from those in other children, not only due to the characteristics of their disorder, but also because of lower stress reactivity.  相似文献   
108.
109.
110.
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