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   8209篇
  免费   411篇
  国内免费   23篇
耳鼻咽喉   89篇
儿科学   276篇
妇产科学   232篇
基础医学   1024篇
口腔科学   509篇
临床医学   598篇
内科学   1659篇
皮肤病学   210篇
神经病学   572篇
特种医学   258篇
外科学   972篇
综合类   158篇
一般理论   4篇
预防医学   923篇
眼科学   141篇
药学   594篇
  1篇
中国医学   104篇
肿瘤学   319篇
  2023年   63篇
  2022年   54篇
  2021年   135篇
  2020年   102篇
  2019年   130篇
  2018年   253篇
  2017年   216篇
  2016年   200篇
  2015年   296篇
  2014年   276篇
  2013年   400篇
  2012年   614篇
  2011年   650篇
  2010年   304篇
  2009年   233篇
  2008年   510篇
  2007年   450篇
  2006年   402篇
  2005年   402篇
  2004年   343篇
  2003年   263篇
  2002年   224篇
  2001年   178篇
  2000年   147篇
  1999年   145篇
  1998年   65篇
  1997年   66篇
  1996年   55篇
  1995年   52篇
  1994年   71篇
  1993年   43篇
  1992年   69篇
  1991年   73篇
  1990年   54篇
  1989年   71篇
  1988年   69篇
  1987年   62篇
  1986年   57篇
  1985年   40篇
  1984年   37篇
  1983年   31篇
  1981年   29篇
  1980年   22篇
  1967年   18篇
  1959年   36篇
  1958年   58篇
  1957年   89篇
  1956年   47篇
  1955年   76篇
  1954年   67篇
排序方式: 共有8643条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
76.
Non-communicable diseases account for more than 50% of deaths in adults aged 15–59 years in most low income countries. Depression and diabetes carry an enormous public health burden, making the identification of risk factors for these disorders an important strategy. While socio-economic inequalities in chronic diseases and their risk factors have been studied extensively in high-income countries, very few studies have investigated social inequalities in chronic disease risk factors in low or middle-income countries. Documenting chronic disease risk factors is important for understanding disease burdens in poorer countries and for targeting specific populations for the most effective interventions. The aim of this review is to systematically map the evidence for the association of socio-economic status with diabetes and depression comorbidity in low and middle income countries. The objective is to identify whether there is any evidence on the direction of the relationship: do co-morbidities have an impact on socio-economic status or vice versa and whether the prevalence of diabetes combined with depression is associated with socio-economic status factors within the general population. To date no other study has reviewed the evidence for the extent and nature of this relationship. By systematically mapping the evidence in the broader sense we can identify the policy and interventions implications of existing research, highlight the gaps in knowledge and suggest future research. Only 14 studies were found to analyse the associations between depression and diabetes comorbidity and socio-economic status. Studies show some evidence that the occurrence of depression among people with diabetes is associated with lower socio-economic status. The small evidence base that considers diabetes and depression in low and middle income countries is out of step with the scale of the burden of disease.  相似文献   
77.
ObjectiveTo describe the seminiferous epithelium cycle (SEC) by tubular morphology method, and the acrosomal development of individualizing spermatids, and to explore the distinction of the stages between two generations of spermatids.MethodsTesticular fragments were fixed in Karnovsky, embedded in glycol methacrylate and examined under light microscopy and transmission electron microscopy. Sections in 3 μm thickness were stained with toluidine blue for the characterization of the stages of the SEC by the tubular morphology method, or submitted to the PAS reaction for the visualization of the acrosomal formation. Additional details on the acrosomal formation were observed under transmission electron microscopy.ResultsThrough the eight stages described by tubular morphology method, 10 steps of acrosomal formation were observed in the spermatid development, called acrosomal steps. As the spermatids were produced in stage V of the tubular morphology method, it was at this stage from which began the steps of acrosomal development.ConclusionsWe propose association of the acrosomal steps for the first time, with the different stages by tubular morphology method. This method presents an alternative to the existent Methods, allowing interspecific comparisons of the SEC, not only among different species of bats, but also among the other mammals.  相似文献   
78.
79.
80.
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