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   384392篇
  免费   24723篇
  国内免费   3161篇
耳鼻咽喉   5206篇
儿科学   8271篇
妇产科学   10114篇
基础医学   53682篇
口腔科学   11850篇
临床医学   30771篇
内科学   78972篇
皮肤病学   8580篇
神经病学   27438篇
特种医学   14131篇
外国民族医学   84篇
外科学   61025篇
综合类   11053篇
现状与发展   1篇
一般理论   64篇
预防医学   17856篇
眼科学   9594篇
药学   31738篇
  6篇
中国医学   2561篇
肿瘤学   29279篇
  2021年   2949篇
  2019年   2923篇
  2018年   4711篇
  2017年   3610篇
  2016年   3690篇
  2015年   4289篇
  2014年   6010篇
  2013年   7689篇
  2012年   10470篇
  2011年   10662篇
  2010年   6552篇
  2009年   6147篇
  2008年   9798篇
  2007年   10591篇
  2006年   10467篇
  2005年   9492篇
  2004年   8936篇
  2003年   8650篇
  2002年   8311篇
  2001年   28321篇
  2000年   28859篇
  1999年   23724篇
  1998年   5208篇
  1997年   4295篇
  1996年   3869篇
  1995年   3507篇
  1994年   3131篇
  1993年   2862篇
  1992年   16063篇
  1991年   14823篇
  1990年   14164篇
  1989年   13967篇
  1988年   12585篇
  1987年   12063篇
  1986年   11109篇
  1985年   10324篇
  1984年   6912篇
  1983年   5599篇
  1982年   2718篇
  1979年   5477篇
  1978年   3347篇
  1977年   2971篇
  1975年   2641篇
  1974年   3064篇
  1973年   2865篇
  1972年   2828篇
  1971年   2773篇
  1970年   2510篇
  1969年   2543篇
  1968年   2250篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
The effect of a carbon dioxide (CO2) pneumoperitoneum and its duration on rabbit follicular oocytes was assessed by evaluating fertilization and subsequent embryonic development rates. CO2 may cross the plasma membrane and form carbonic acid, which liberates H+, thus lowering the intracellular pH. There were no significant differences in arterial pH and [HCO3-] between CO2 and air treatment groups, whereas arterial pCO2 and pO2 were significantly increased in the CO2 treatment group. We found that the duration of pneumoperitoneum, irrespective of type of gas used, was negatively correlated with success of embryonic development. These findings necessitate that more attention be given to the gas used for creation of a pneumoperitoneum during egg retrieval for in vitro fertilization and an attempt be made to minimize duration of the pneumoperitoneum.  相似文献   
994.
A 16 year old girl with post-streptococcal glomerulonephritis developed acute rheumatic fever 19 days afterwards. Previous publications on concurrent post-streptococcal glomerulonephritis and acute rheumatic fever are reviewed.  相似文献   
995.
996.
997.
Summary In a study of 11 adult patients with acute nonlymphocytic leukemia (ANLL), infusion therapy with high-dose VP-16 and intermediate-dose cytosine arabinoside was administered. Response was assessed with reference to bone marrow aspirations performed on days 1; 12, 13, or 14; and 21 of treatment. All 7 of the patients with ANLL in relapse achieved marrow hypoplasia, and 3 of them achieved complete response. LFTs were elevated in most patients but no evidence of hepatocellular necrosis was observed. It is concluded that the value of VP-16 in ANLL may have been underestimated in the past because of inadequate dosing.Abbreviations ANLL acute nonlymphocytic leukemia - CGL chronic granulocytic leukemia - DNR daunorubicin - VNC vincristine - ID Ara-C, intermediate-dose Ara-C (500 mg/m2 for 12 doses) - HD Ara-C, high-dose Ara-C (3 g/m2 for 12 doses) - SGGT serum glutamic transaminase - LDH lactic dehydrogenase - SGOT serum glutamic oxaloacetic transaminase  相似文献   
998.
To investigate the responses of nasal vessels, divided into resistance and capacitance vessels, to a beta-receptor agonist in human, mucosal blood flow of the inferior turbinate and nasal airway resistance were measured when 1.5 mg terbutaline was applied topically. Mucosal blood flow was measured by the hydrogen clearance method just beneath the site where terbutaline in physiological saline (0.02 ml) was applied on an extremely localized area of the nasal mucosa. Nasal airway resistance of the ipsilateral and contralateral nasal cavities was measured separately by anterior rhinomanometry when terbutaline in normal saline (0.1 ml) was sprayed in the unilateral nasal cavity. Topical application of terbutaline elicited neither a significant increase of mucosal blood flow of the inferior turbinate nor an increase of nasal airway resistance. beta-Receptors seem not to be as densely distributed both in the resistance vessels and in the capacitance vessels as to cause vasodilatation by their activation in the nasal mucosa.  相似文献   
999.
Axonal spheroids in the posterior column nuclei of phenytoin-intoxicated epileptics were classified according to their predominant subcellular components into six types, and their incidences were compared with those in controls. Spheroids from phenytoin-intoxicated epileptics showed significantly higher proportions of the tubulomembranous (TM) and layered membrane loop (LML) types in the gracile nucleus, appearance of the same types in the cuneate nucleus, and a significant decrease of the neurofilamentous (NF) type in both nuclei. The incidences of the complex body (CB) and granular material types and of the homogeneous dense-body (HDB) type, which appeared only in the gracile nucleus, showed no difference between the intoxicated patients and the controls. The NF, CB and HDB types were therefore considered to be nonspecific. It was thought that chronic phenytoin intoxication might induce dystrophic changes, such as those characterized by the presence of the TM and LML types, in the axon terminals of the gracile and cuneate nuclei, possibly due to some abnormalities of the axoplasmic transport system.  相似文献   
1000.
Ca2+ mobilization and phosphoinositide turnover were examined during phagocytosis of latex particles in cultured chick retinal pigment epithelial cells (RPE cells). Ca2+ influx into cells and Ca2+ efflux from the cells were enhanced by about 1.5-fold and 3-fold compared to control cells, respectively. A high content of Ca2+ in RPE cells has been reported. Therefore, the Ca2+ efflux observed here may be a reflection of Ca2+ release into cytosol from the intracellular storage site(s). In [3H] inositol-prelabeled RPE cells, addition of latex particles elicited decreases in phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol with the concomitant formation of inositol phosphates including inositol trisphosphate, indicating the hydrolysis of phosphoinositides by phospholipase C. These results suggest that phosphoinositide turnover may be closely coupled with Ca2+ mobilization during phagocytosis in RPE cells.  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