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   7231篇
  免费   413篇
  国内免费   36篇
耳鼻咽喉   214篇
儿科学   170篇
妇产科学   221篇
基础医学   978篇
口腔科学   375篇
临床医学   530篇
内科学   1683篇
皮肤病学   123篇
神经病学   548篇
特种医学   171篇
外国民族医学   1篇
外科学   1192篇
综合类   35篇
预防医学   573篇
眼科学   156篇
药学   356篇
中国医学   37篇
肿瘤学   317篇
  2023年   46篇
  2022年   93篇
  2021年   212篇
  2020年   125篇
  2019年   208篇
  2018年   222篇
  2017年   133篇
  2016年   178篇
  2015年   244篇
  2014年   331篇
  2013年   360篇
  2012年   575篇
  2011年   631篇
  2010年   365篇
  2009年   280篇
  2008年   472篇
  2007年   503篇
  2006年   489篇
  2005年   421篇
  2004年   376篇
  2003年   315篇
  2002年   292篇
  2001年   106篇
  2000年   90篇
  1999年   65篇
  1998年   46篇
  1997年   33篇
  1996年   26篇
  1995年   18篇
  1994年   27篇
  1993年   19篇
  1992年   27篇
  1991年   47篇
  1990年   36篇
  1989年   29篇
  1988年   23篇
  1987年   25篇
  1986年   25篇
  1985年   17篇
  1984年   17篇
  1983年   12篇
  1982年   12篇
  1981年   13篇
  1980年   18篇
  1979年   14篇
  1978年   8篇
  1976年   8篇
  1975年   7篇
  1973年   11篇
  1970年   6篇
排序方式: 共有7680条查询结果,搜索用时 218 毫秒
1.
2.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
3.
4.
5.
6.
7.
8.
9.
Originally described by Rosen in 1983, syringomatous nipple adenoma (SAN) is a tumor of disputed histogenesis, which can be problematic both diagnostically and therapeutically. 1 It is a benign primary tumor of breast epithelium with histology similar to that of the syringoma. In the current case, we describe a 40-year-old female with this lesion occurring within a supernumerary breast. This case represents, to our knowledge, the first such reported case, and represents a significant finding as its presence could lend some confusion as to whether or not this represents a benign primary process of breast or a potentially infiltrative tumor of the skin.  相似文献   
10.
Opioid receptor binding was evaluated in parahippocampal cortex (PHC) obtained from patients with intractable mesial temporal lobe epilepsy (MTLE) with and without subacute high frequency electrical stimulation (HFS) in this brain area. Mu, delta and nociceptin receptor binding was determined by autoradiography in PHC of five patients (ESAE group) with MTLE history of 14.8 +/- 2.5 years and seizure frequency of 11 +/- 2.9 per month, two of them (40%) with mesial sclerosis. This group demonstrated antiepileptic effects following subacute HFS (130 Hz, 450 micros, 200-400 microA), applied continuously during 16-20 days in PHC. Values were compared with those obtained from patients with severe MTLE (history of 21.7 +/- 2.8 years and seizure frequency of 28.2 +/- 14 per month) in whom electrical stimulation did not induce antiepileptic effects (ESWAE group, n = 4), patients with MTLE in whom no electrical stimulation was applied (MTLE group, n = 4) and autopsy material acquired from subjects without epilepsy (n = 4 obtained from three subjects). Enhanced 3H-DAMGO (MTLE, 755%; ESAE, 375%; ESWAE, 693%), 3H-DPDPE (MTLE, 242%; ESAE, 80%; ESWAE, 346%) and 3H-nociceptin (MTLE, 424%; ESAE, 217%; ESWAE, 451%) binding was detected in the PHC of all epileptic groups. However, tissue obtained from ESAE group demonstrated lower opioid receptor binding (3H-DAMGO, 44.5%, p < 0.05; 3H-DPDPE, 47%, p < 0.05; 3H-nociceptin, 39.3%, p < 0.5) when compared with MTLE group. The present results indicate that a high effectiveness to the antiepileptic effects induced by HFS is associated with reduced opioid peptide binding.  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