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   5265篇
  免费   282篇
  国内免费   34篇
耳鼻咽喉   38篇
儿科学   94篇
妇产科学   28篇
基础医学   626篇
口腔科学   79篇
临床医学   382篇
内科学   1667篇
皮肤病学   53篇
神经病学   390篇
特种医学   96篇
外科学   980篇
综合类   28篇
预防医学   160篇
眼科学   137篇
药学   337篇
中国医学   18篇
肿瘤学   468篇
  2023年   31篇
  2022年   38篇
  2021年   61篇
  2020年   45篇
  2019年   44篇
  2018年   53篇
  2017年   56篇
  2016年   77篇
  2015年   86篇
  2014年   95篇
  2013年   100篇
  2012年   193篇
  2011年   266篇
  2010年   147篇
  2009年   171篇
  2008年   247篇
  2007年   248篇
  2006年   294篇
  2005年   279篇
  2004年   267篇
  2003年   246篇
  2002年   291篇
  2001年   234篇
  2000年   226篇
  1999年   173篇
  1998年   64篇
  1997年   48篇
  1996年   53篇
  1995年   40篇
  1993年   29篇
  1992年   93篇
  1991年   94篇
  1990年   70篇
  1989年   97篇
  1988年   95篇
  1987年   97篇
  1986年   97篇
  1985年   79篇
  1984年   47篇
  1983年   64篇
  1982年   35篇
  1980年   36篇
  1979年   58篇
  1978年   32篇
  1973年   33篇
  1970年   26篇
  1969年   29篇
  1968年   34篇
  1967年   31篇
  1966年   30篇
排序方式: 共有5581条查询结果,搜索用时 15 毫秒
41.
Oxygen-related free radicals have been suggested as a cause of aging and various diseases, for example, various cancers and rheumatoid arthritis. A radical scavenger as an antioxidant has been sought in foods. Fish sauces are traditional Asian fermented seasonings. Using the luminol chemiluminescence method, the peroxyl radical scavenging capability of fish sauces was examined. From the IC50 values, many fish sauces have been shown to have a strong scavenging capability as well as soy sauces. A scavenging mechanism is also proposed.  相似文献   
42.
Incidental virus particles in chicken heart valve   总被引:1,自引:0,他引:1  
  相似文献   
43.
CD56 antigen (detected by NKH-1) is distributed on NK cells, monocytes, and ectodermal neural cells. In this study, the blasts of 29.2% of 27 patients with acute nonlymphocytic leukemia (ANLL) expressed CD56 antigen, but not CD16, CD2, or CD3 antigen. Leukemic cells isolated from 3 patients with CD56-positive ANLL did not have NK activity. There were no significant differences between CD56-positive and CD56-negative ANLL in CD13-positive cases, CD33-positive cases, and HLA-DR-positive cases. These results suggest that CD56-positive ANLL could be so-called mixed-lineage leukemia (lymphoid-associated antigen in ANLL).  相似文献   
44.
Hereditary coproporphyria (HCP) is an acute hepatic porphyriawith autosomal dominant inheritance, but with a variable degreeof clinical expression. Molecular cloning, sequencing and expressionof the defective gene for coproporphyrinogen oxidase (CPO) ina patient with HCP were carried out. Enzyme assays revealedthat CPO activity in EBV-transformed lymphoblastoid cells fromthe proband and one of her sisters was  相似文献   
45.
46.
The cavernous body in the lamprey gill filament was studied by electron microscopy. This body lies along the outer border of the axial plate of each gill filament and freely communicates with an afferent filament artery. Two series of blood channels run alternately, passing through the cavernous body, and lead to the marginal channels in the secondary lamellae. On the other hand, narrow blood spaces left in the cavernous body lead to the blood lacunae in the axial plate (osmoregulatory region) and to those in the secondary lamellae (respiratory region). All the blood in the cavernous body is finally collected by an efferent filament artery. The cavernous body is traversed by numerous trabeculae and collagenous columns which run diagonally in the blood spaces to connect the walls of the cavernous body. All the walls of the cavernous body, including trabeculae and collagenous columns, are completely surrounded by the cytoplasmic flanges of specialized cells called here “cavernous body cells.” These cells are about 30 μm in diameter and characterized by (1) association with collagenous columns or trabeculae and also by the presence of (2) coated caveolae and vesicles, (3) vacuoles and (4) cytoplasmic granules in their cytoplasm. These cells are considered to be related to the pillar cells in origin because of their close association with collagenous columns or trabeculae. The functional significance of the cavernous body and the cavernous body cells is discussed.  相似文献   
47.
48.
49.
Accumulating evidence indicates that grafts of embryonic neurons achieve the anatomical and functional reconstruction of damaged neuronal circuitry. The restorative capacity of grafted embryonic neural tissue is most illustrated by studies with striatal tissue transplantation in animals with striatal lesions. Striatal neurons implanted into the lesioned striatum receive some of the major striatal afferents such as the nigrostriatal dopaminergic inputs and the gluatmatergic afferents from the neocortex and thalamus. The grafted neurons also send efferents to the primary striatal targets, including the globus pallidus (GP, the rodent homologue of the external segment of the globus pallidus) and the entopeduncular nucleus (EP, the rodent homologue of the internal segment of the globus pallidus). These anatomical connections provide the reversal of the lesion-induced alterations in neuronal activities of primary and secondary striatal targets. Furthermore, intrastriatal striatal grafts improve motor and cognitive deficits seen in animals with striatal lesions. Since the grafts affect motor and cognitive behaviors that are critically dependent on the integrity of neuronal circuits of the basal ganglia, the graft-mediated recovery in these behavioral deficits is most likely attributable to the functional reconstruction of the damaged neuronal circuits. The fact that the extent of the behavioral recovery is positively correlated to the amount of grafted neurons surviving in the striatum encourages this view. Based on the animal studies, embryonic striatal tissue grafting could be a viable strategy to alleviate motor and cognitive disorders seen in patients with Huntington's disease where massive degeneration of striatal neurons occurs.  相似文献   
50.
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