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   2388篇
  免费   197篇
  国内免费   5篇
耳鼻咽喉   34篇
儿科学   71篇
妇产科学   95篇
基础医学   332篇
口腔科学   33篇
临床医学   277篇
内科学   559篇
皮肤病学   58篇
神经病学   212篇
特种医学   36篇
外科学   297篇
综合类   7篇
一般理论   3篇
预防医学   248篇
眼科学   31篇
药学   101篇
中国医学   2篇
肿瘤学   194篇
  2024年   7篇
  2023年   55篇
  2022年   96篇
  2021年   184篇
  2020年   112篇
  2019年   141篇
  2018年   127篇
  2017年   93篇
  2016年   89篇
  2015年   108篇
  2014年   122篇
  2013年   139篇
  2012年   216篇
  2011年   193篇
  2010年   80篇
  2009年   63篇
  2008年   134篇
  2007年   110篇
  2006年   97篇
  2005年   73篇
  2004年   79篇
  2003年   83篇
  2002年   59篇
  2001年   13篇
  2000年   7篇
  1999年   8篇
  1998年   11篇
  1997年   12篇
  1996年   9篇
  1995年   4篇
  1994年   7篇
  1993年   3篇
  1992年   4篇
  1991年   2篇
  1989年   2篇
  1988年   5篇
  1987年   4篇
  1986年   7篇
  1984年   5篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   2篇
  1978年   2篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1935年   2篇
  1934年   1篇
  1929年   1篇
排序方式: 共有2590条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.

Objective

To provide a comprehensive review and evidence-based recommendations for the delivery of fertility care to women with obesity.

Outcomes

The impact of obesity on fertility, fertility treatments, and both short and long-term maternal fetal outcomes was carefully considered.

Evidence

Published literature was reviewed through searches of MEDLINE and CINAHL using appropriate vocabulary and key words. Results included systematic reviews, clinical trials, observational studies, clinical practice guidelines, and expert opinions.

Values

The Canadian Fertility & Andrology Society (CFAS) is a multidisciplinary, national non-profit society that serves as the voice of reproductive specialists, scientists, and allied health professionals working in the field of assisted reproduction in Canada. The evidence obtained for this guideline was reviewed and evaluated by the Clinical Practice Guideline (CPG) Committee of the CFAS under the leadership of the principal authors.

Benefits, Harms, and Costs

The implementation of these recommendations should assist clinicians and other health care providers in counselling and providing reproductive care to women with obesity.

Validation

This guideline and its recommendations have been reviewed and approved by the membership, the CPG Committee and the Board of Directors of the CFAS.

Sponsors

Canadian Fertility & Andrology Society.

Recommendations

Twenty-one evidence based recommendations are provided. These recommendations specifically evaluate the impact of obesity on natural fertility, fertility treatments, and maternal-fetal outcomes. Strategies to lose weight and BMI cut-offs are also addressed.  相似文献   
996.
Liver transplantation for critically ill cirrhotic patients with acute deterioration of liver function associated with extrahepatic organ failures is controversial. While transplantation has been shown to be beneficial on an individual basis, the potentially poorer post-transplant outcome of these patients taken as a group can be held as an argument against allocating livers to them. Although this issue concerns only a minority of liver transplants, it calls into question the very heart of the allocation paradigms in place. Indeed, most allocation algorithms have been centered on prioritizing the sickest patients by using the model for end-stage liver disease score. This has led to allocating increasing numbers of livers to increasingly critically ill patients without setting objective or consensual limits on how sick patients can be when they receive an organ. Today, finding robust criteria to deem certain cirrhotic patients too sick to be transplanted seems urgent in order to ensure the fairness of our organ allocation protocols. This review starts by fleshing out the argument that finding such criteria is essential. It examines five types of difficulties that have hindered the progress of recent literature on this issue and identifies various strategies that could be followed to move forward on this topic, taking into account the recent discussion on acute on chronic liver failure. We move on to review the literature along four axes that could guide clinicians in their decision-making process regarding transplantation of critically ill cirrhotic patients.  相似文献   
997.
998.
Few neuroimaging studies are sufficiently large to adequately describe population‐wide variations. This study''s primary aim was to generate neuroanatomical norms and individual markers that consider age, sex, and brain size, from 629 cerebral measures in the UK Biobank (N = 40,028). The secondary aim was to examine the effects and interactions of sex, age, and brain allometry—the nonlinear scaling relationship between a region and brain size (e.g., total brain volume)—across cerebral measures. Allometry was a common property of brain volumes, thicknesses, and surface areas (83%) and was largely stable across age and sex. Sex differences occurred in 67% of cerebral measures (median |β| = .13): 37% of regions were larger in males and 30% in females. Brain measures (49%) generally decreased with age, although aging effects varied across regions and sexes. While models with an allometric or linear covariate adjustment for brain size yielded similar significant effects, omitting brain allometry influenced reported sex differences in variance. Finally, we contribute to the reproducibility of research on sex differences in the brain by replicating previous studies examining cerebral sex differences. This large‐scale study advances our understanding of age, sex, and brain allometry''s impact on brain structure and provides data for future UK Biobank studies to identify the cerebral regions that covary with specific phenotypes, independently of sex, age, and brain size.  相似文献   
999.
The rise in prevalence of obesity in women of reproductive age in developed and developing countries might propagate intergenerational cycles of detrimental effects on metabolic health. Placental lipid metabolism is disrupted by maternal obesity, which possibly affects the life-long health of the offspring. Here, we investigated placental lipid metabolism in women with pre-gestational obesity as a sole pregnancy complication and compared it to placental responses of lean women. Open profile and targeted lipidomics were used to assess placental lipids and oxidised products of docosahexaenoic (DHA) and arachidonic acid (AA), respectively, neuroprostanes and isoprostanes. Despite no overall signs of lipid accumulation, DHA and AA levels in placentas from obese women were, respectively, 2.2 and 2.5 times higher than those from lean women. Additionally, a 2-fold increase in DHA-derived neuroprostanes and a 1.7-fold increase in AA-derived isoprostanes were seen in the obese group. These changes correlated with a 70% decrease in placental FABP1 protein. Multivariate analyses suggested that neuroprostanes and isoprostanes are associated with maternal and placental inflammation and with birth weight. These results might shed light on the molecular mechanisms associated with altered placental fatty acid metabolism in maternal pre-gestational obesity, placing these oxidised fatty acids as novel mediators of placental function.  相似文献   
1000.
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