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   32912篇
  免费   739篇
  国内免费   53篇
耳鼻咽喉   1254篇
儿科学   797篇
妇产科学   2628篇
基础医学   4372篇
口腔科学   1052篇
临床医学   1346篇
内科学   5734篇
皮肤病学   883篇
神经病学   3217篇
特种医学   462篇
外科学   2953篇
综合类   92篇
一般理论   1篇
预防医学   2398篇
眼科学   1424篇
药学   4249篇
中国医学   55篇
肿瘤学   787篇
  2022年   236篇
  2021年   503篇
  2020年   233篇
  2019年   387篇
  2018年   717篇
  2017年   487篇
  2016年   523篇
  2015年   496篇
  2014年   828篇
  2013年   1150篇
  2012年   1435篇
  2011年   1743篇
  2010年   903篇
  2009年   424篇
  2008年   1068篇
  2007年   1531篇
  2006年   1642篇
  2005年   1558篇
  2004年   1670篇
  2003年   1672篇
  2002年   1393篇
  2001年   940篇
  2000年   981篇
  1999年   734篇
  1998年   226篇
  1992年   379篇
  1991年   328篇
  1990年   370篇
  1989年   407篇
  1988年   466篇
  1987年   456篇
  1986年   463篇
  1985年   434篇
  1984年   355篇
  1983年   265篇
  1979年   532篇
  1978年   330篇
  1977年   267篇
  1976年   252篇
  1975年   347篇
  1974年   508篇
  1973年   515篇
  1972年   430篇
  1971年   403篇
  1970年   391篇
  1969年   407篇
  1968年   353篇
  1967年   267篇
  1966年   297篇
  1965年   178篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
A series of amino acid derivatives of indometacin (IND) was investigated in regard to their protein binding and prostaglandin synthetase inhibition in vitro, and to acute toxicity, anti-inflammatory, antiedemic, analgesic actions, and the influence on the central nervous system in vivo. In biochemical tests the compounds were several times less potent than IND. They differed among themselves in the respect of toxicity, which was always much lower than that of IND. Out of eight compounds investigated N-IND-glycine (K1) and N-IND-epsilon-aminocaproic acid (K5) exerted more favorable antiedemic and analgesic action than IND did. Both the derivatives only weakly inhibited the cotton-pellet granuloma formation. K1 acted similarly to IND in the arthritis test. K1, K5 and IND similarly irritated the gastric mucosa. A modification of IND structure by introduction of glycine or epsilon-aminocaproic acid resulted in two new anti-inflammatory agents of more favorable therapeutic index in the antiedemic and analgesic action and of much lower toxicity than the reference compound.  相似文献   
63.
64.
Cytogenetic examinations were carried out in 40 children with acute leukaemia. In 18 cases karyotype changes were demonstrated, in 8 cases the karyotype was normal, in 14 cases no cell division was obtained and these patients were excluded from further analysis. In the group with karyotype changes in most cases poor prognosis indices were found, including high number of blasts, extramedullary presence of leukaemic infiltrations and FAB L2 or L3. Chromosomal abnormalities included presence of aberrations in the form of translocation, mosaicism of karyotypes with nearly tetraploidy line, accessory marker chromosomes and other anomalies. In this group 8 children died (30% of all observed cases), while in the group without karyotype changes 2 children died (about 8%). In summary the authors stress the correlation between the presence of clinical prognostic factors (risk factors) and karyotype changes and worse prognosis in cases with chromosomal abnormalities. Attention is called to the great usefulness of cytogenetic examinations in the prognosis and treatment of leukaemias in children.  相似文献   
65.
In six young and two senile MS cases perivascular astrocytes within demyelination lesions were evaluated immunocytochemically. The peroxidase-antiperoxidase method of Sternberger et al. (1970) was used for visualization of glial fibrillary acidic protein (GFAP). In all cases very weak immunoreactivity of perivascular astrocytes was noted. Accumulation of perivascular glial fibers, and infrequently their fragmentation were observed both within active and old demyelination plaques. Clasmatodendrosis, Rosenthal's fibers and prominent regressive changes of astrocyte perikarya were found only in old plaques. A lack of immunoreactivity of perivascular astrocytes was noted within old demyelination lesions. The background of the latter was often immunonegative to GFAP. It is suggested that secondary damage of perivascular astrocytes influences vascular permeability within demyelination lesions including old plaques.  相似文献   
66.
67.
Alprazolam, a new benzodiazepine from triazolobenzodiazepine group, produced anxiolytic action in the conflict test with potency similar to that of diazepam. The myorelaxant activity of the drug was relatively weak. Unlike desipramine, alprazolam failed to reduce the immobility of rats in the forced swim test and was unable to prevent clonidine-induced hypothermia. Alprazolam, unlike desipramine, failed also to potentiate behavioral effect of noradrenaline injected into the hippocampus. Alprazolam after acute but not chronic administration antagonized the synchronizing effect of clonidine on EEG pattern. On the other hand, alprazolam similarly to tricyclic antidepressants, prevented the suppression of dominance behavior by clonidine in rats competing for food. The results indicate that alprazolam acts only weakly upon noradrenergic mechanisms related to depression and to antidepressant action of drugs.  相似文献   
68.
A case of primary malignant lymphoma of the eye in a 78-year-old woman is reported. A centroblastic non-Hodgkin lymphoma showed prominent involvement of the retina with massive serous retinal detachment. A review of the literature is given.  相似文献   
69.
70.
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