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   1074篇
  免费   39篇
耳鼻咽喉   22篇
儿科学   39篇
妇产科学   32篇
基础医学   105篇
口腔科学   27篇
临床医学   47篇
内科学   237篇
皮肤病学   16篇
神经病学   49篇
特种医学   86篇
外科学   197篇
综合类   17篇
预防医学   57篇
眼科学   43篇
药学   68篇
中国医学   14篇
肿瘤学   57篇
  2023年   7篇
  2022年   28篇
  2021年   51篇
  2020年   23篇
  2019年   34篇
  2018年   31篇
  2017年   32篇
  2016年   31篇
  2015年   35篇
  2014年   46篇
  2013年   60篇
  2012年   108篇
  2011年   65篇
  2010年   33篇
  2009年   18篇
  2008年   51篇
  2007年   52篇
  2006年   54篇
  2005年   46篇
  2004年   37篇
  2003年   26篇
  2002年   24篇
  2001年   29篇
  2000年   19篇
  1999年   14篇
  1998年   11篇
  1997年   3篇
  1996年   5篇
  1995年   8篇
  1994年   5篇
  1993年   3篇
  1992年   9篇
  1991年   7篇
  1990年   7篇
  1989年   8篇
  1988年   5篇
  1987年   8篇
  1986年   11篇
  1985年   8篇
  1981年   3篇
  1980年   4篇
  1979年   10篇
  1978年   7篇
  1976年   3篇
  1974年   3篇
  1973年   3篇
  1970年   3篇
  1969年   4篇
  1968年   4篇
  1967年   2篇
排序方式: 共有1113条查询结果,搜索用时 15 毫秒
11.
It has been traditionally accepted that maternal and fetal complications are at their lowest levels 37-42 weeks into gestation. 20% of pregnancies completed after 42 weeks gestation are thought to be affected by the postmaturity syndrome of uteroplacental insufficiency resulting in oligohydramnios, meconium passage, loss of fetal subcutaneous tissue, fetal asphyxia, and fetal death. Some workers, however, have also found that pregnancies completed between 40 and 42 weeks carry significant risk. The authors explored this question in a case-control study of 464 women seen at the Mahatma Gandhi Institute of Medical Sciences in Maharashtra, India. The cases of postdatism occurred in the absence of any other medical or obstetric problem. The operative delivery rate increased significantly among these patients compared to deliveries between 39 and 40 weeks. There was neither significant asphyxia nor perinatal loss in term completed normal patients. Asphyxia and perinatal mortality did, however, occur with postdatism. The authors note the likely role of oligohydramnios combined with placental dysfunction.  相似文献   
12.
Volume 21, Number 2 (1993), in the article "Comparative Carcinogenicityof 5,5-Diphenyihydantoin with or without Perinatal Exposurein Rats and Mice," by R. S. Chhabra, J. R. Bucher, J. K. Haseman,M. R. Elwell, P. J. Kurtz, and B. D. Canton, pages 174–186:Since the publication of the above article, the authors havefound that the feed and estimated DPH consumption data reportedin Tables 2 and 6 were incorrect. The following Tables 2 and6 contain revised feed and DPH consumption data:  相似文献   
13.
14.
Adolescents are the future adults of the world. While adolescence is typically regarded as a period of life relatively free from health problems, adolescents are actually in need of the attention of health professionals and health services, especially with regard to sexual health. A trend of decreasing age at menarche and increasing age at marriage presents adolescents with a substantial number of years in which they will experiment with their developing reproductive organs and sexuality. Substantial psychological and physical change takes place during this period. Inconsistent and suboptimal users of contraception, youths are at high risk for reproductive health problems and sexually transmitted diseases. Substance abuse, unintentional and intentional injuries and their sequelae, academic underachievement and illiteracy, and obesity may also be problematic for adolescents. Adolescents are, however, most damaged by internalized and externalized homophobia. The authors point out that adolescents may be persuaded to learn and change their behaviors more readily than adults. Appropriate messages could be conveyed through targeted information, education, and communication strategies to complement medical and health care services which are available, accessible, and acceptable.  相似文献   
15.
The mechanisms underlying lateralisation of language are incompletely understood. Existing data is inconclusive, for example, in determining which underlying asymmetries in hemispheric anatomy/physiology lead to lateralisation, the precise role of interhemispheric connections in this process, and exactly how and why lateralisation can shift following focal brain damage. Although these issues will ultimately be settled by experimentation, it is likely that computational modelling can be used to suggest, focus, and even interpret such empirical work. We have recently studied the emergence of lateralisation in an artificial neural network model having paired cerebral hemispheric regions, as the model learned to generate the correct pronunciation for simple words. In this paper we extend this previous work by examining the immediate and longer-term changes in lateralisation that occur following simulated acute hemispheric lesions. Among other things, the results demonstrate that the extent to which the non-lesioned model hemispheric region contributes to recovery is a function of lesion size, prelesion lateralisation, and assumptions about the excitatory/inhibitory influences of the corpus callosum. The relevance of these results to the currently controversial suggestion that language lateralisation shifts following focal damage to language areas, and that the unlesioned hemisphere contributes to recovery from stroke-induced aphasia in adults, is discussed.  相似文献   
16.
Here 15 cases of advanced Juvenile angiofibroma are presented. Advantages of wide tumour exposure and preoperative embolization are discussed.  相似文献   
17.
Styrene acrylonitrile (SAN) trimer is a by-product in the production of acrylonitrile styrene plastics. Following a report of a childhood cancer cluster in the Toms River section of Dover Township, New Jersey, SAN Trimer was identified as one of the groundwater contaminants at Reich Farm Superfund site in the township. The contaminants from the Reich Farm site's ground water plume impacted two wells at the Parkway well field. The National Toxicology Program (NTP) studied the toxicity and carcinogenicity of SAN Trimer in rats exposed during their perinatal developmental period and adulthood. The chronic toxicity and carcinogenicity studies in F344/N rats were preceded by 7- and 18-week perinatal toxicity studies to determine the exposure concentrations for the 2-year studies. Subsequently, Fisher 344 pregnant dams were exposed to SAN Trimer containing diet at 400, 800, or 1600 ppm concentrations during gestation, nursing and weaning periods of offspring followed by two year of adult exposures to both male and female pups. There was no statistically significant evidence of carcinogenic activity following SAN-Trimer exposure; however, rare neoplasms in the brain and spinal cord were observed in males and to lesser extent in female rats. These incidences were considered within the range of historical background in the animal model used in the current studies. Therefore, the presence of a few rarely occurring CNS tumors in the treated groups were not judged to be associated with the SAN Trimer exposure. The major finding was a dose-related peripheral neuropathy associated with the sciatic nerves in females and spinal nerve roots in males and females thereby suggesting that SAN Trimer is potentially a nervous system toxicant.  相似文献   
18.
19.
20.
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