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   612篇
  免费   57篇
耳鼻咽喉   2篇
儿科学   44篇
妇产科学   14篇
基础医学   69篇
口腔科学   18篇
临床医学   72篇
内科学   139篇
皮肤病学   28篇
神经病学   24篇
特种医学   87篇
外科学   47篇
综合类   22篇
预防医学   26篇
眼科学   9篇
药学   46篇
中国医学   2篇
肿瘤学   20篇
  2020年   2篇
  2019年   3篇
  2018年   3篇
  2017年   8篇
  2016年   5篇
  2015年   9篇
  2014年   16篇
  2013年   27篇
  2012年   6篇
  2011年   13篇
  2010年   27篇
  2009年   27篇
  2008年   17篇
  2007年   22篇
  2006年   17篇
  2005年   20篇
  2004年   15篇
  2003年   18篇
  2002年   15篇
  2001年   7篇
  2000年   5篇
  1999年   6篇
  1998年   22篇
  1997年   45篇
  1996年   31篇
  1995年   22篇
  1994年   24篇
  1993年   21篇
  1992年   19篇
  1991年   7篇
  1990年   15篇
  1989年   35篇
  1988年   21篇
  1987年   16篇
  1986年   20篇
  1985年   15篇
  1984年   6篇
  1983年   4篇
  1982年   2篇
  1981年   4篇
  1980年   7篇
  1979年   2篇
  1978年   4篇
  1977年   9篇
  1976年   4篇
  1975年   5篇
  1973年   2篇
  1972年   2篇
  1971年   5篇
  1932年   2篇
排序方式: 共有669条查询结果,搜索用时 15 毫秒
1.
2.
Pharmacological studies suggest that beta-adrenergic receptors (beta AR) in the medial nuclei of the solitary tracts (m-NTS) facilitate presynaptic release of catecholamines and also function at postsynaptic sites. We have localized the antigenic sites for a monoclonal antibody against a peptide corresponding to amino acids 226-239 of beta AR in the m-NTS of rat brain. By light microscopy, immunoperoxidase labeling for this antibody was detected in somata and proximal processes of many small cells that were distributed throughout the rostrocaudal extent of the m-NTS. Electron microscopy confirmed the cytoplasmic localization of beta AR in perikarya and proximal dendrites of neurons. Immunoreactivity occurred as discrete patches associated with cytoplasmic surfaces of plasma membrane and with irregularly-shaped saccules with clear lumen in the immediate vicinity. Select regions of nuclear envelopes, mitochondrial membranes, and rough endoplasmic reticulum were also immunoreactive along their cytoplasmic surfaces. In contrast, the Golgi apparatus was labeled, but infrequently. Immunoreactivity was also detected at numerous post- and occasional presynaptic membrane specializations of select axodendritic junctions. Dual labeling for the beta AR-antibody by the immunoperoxidase method and for a rabbit antiserum against the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), by the immunoautoradiographic method within the same sections, further established the precise cellular relations between beta AR and catecholaminergic neurons. Immunoreactivity for beta AR was detected in numerous perikarya and proximal dendrites that did not show detectable levels of TH. However, a few cells were dually labeled for both antigens, as seen by both light and electron microscopy. The TH-labeled terminals formed synapses at junctions both with and without beta AR-like immunoreactivity. These results from the single and dual labeling studies: (1) confirm biochemical predictions that amino acids 226-239 of beta AR protein reside intracellularly; (2) provide the first ultrastructural evidence for beta AR localization within both pre- and postsynaptic membrane specializations of a subset of catecholaminergic synapses; and (3) suggest select intracellular sites that may be involved with synthesis and/or internalization and degradation of the receptor protein.  相似文献   
3.
AD  Giannoukas  N  Labropoulos  FCT  Smith  GS  Venables  JD  Beard  武婕 《中华脑血管病论坛》2005,3(5):555-560
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章.  相似文献   
4.
5.
6.
“维生素AD、铁营养强化奶的研制”研究报告   总被引:1,自引:0,他引:1  
目的:研制维生素AD、铁营养强化奶,用于群体有效防治维生素AD、铁缺乏.方法:应用微胶囊技术科学配方成维生素AD、铁营养粉,添加到鲜牛奶中.结果:工业化生产维生素AD、铁营养强化奶.结论:该产品取得了很好的社会效益和经济效益.  相似文献   
7.
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi.  相似文献   
8.
Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms.  相似文献   
9.
10.
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