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   12483篇
  免费   929篇
  国内免费   418篇
耳鼻咽喉   58篇
儿科学   128篇
妇产科学   223篇
基础医学   1503篇
口腔科学   461篇
临床医学   1611篇
内科学   1589篇
皮肤病学   166篇
神经病学   496篇
特种医学   789篇
外科学   791篇
综合类   1430篇
现状与发展   1篇
预防医学   1079篇
眼科学   164篇
药学   2286篇
  3篇
中国医学   428篇
肿瘤学   624篇
  2024年   42篇
  2023年   192篇
  2022年   394篇
  2021年   468篇
  2020年   451篇
  2019年   381篇
  2018年   324篇
  2017年   375篇
  2016年   404篇
  2015年   464篇
  2014年   812篇
  2013年   1148篇
  2012年   728篇
  2011年   741篇
  2010年   594篇
  2009年   602篇
  2008年   640篇
  2007年   576篇
  2006年   559篇
  2005年   370篇
  2004年   339篇
  2003年   345篇
  2002年   284篇
  2001年   257篇
  2000年   188篇
  1999年   209篇
  1998年   187篇
  1997年   234篇
  1996年   186篇
  1995年   167篇
  1994年   190篇
  1993年   128篇
  1992年   108篇
  1991年   107篇
  1990年   90篇
  1989年   77篇
  1988年   77篇
  1987年   63篇
  1986年   65篇
  1985年   66篇
  1984年   37篇
  1983年   20篇
  1982年   37篇
  1981年   27篇
  1980年   15篇
  1979年   10篇
  1978年   15篇
  1977年   12篇
  1976年   8篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The clinical history of 1538 HIV positive patients was analyzed on the basis of the new CDC classification system of HIV disease and AIDS. This classification system combines three CD4 cell categories (1, 2, and 3) with three clinical categories (A, B, and C) into nine subgroups AI–C3. We examined the overall survival for all subgroups and the AIDS-free survival for subgroups Al–B3. AIDS-free survival for patients in subgroups Al, A2, and B1 was considerably longer than survival in patients from subgroups A3, B2, and B3 (P < 0.0001). According to these findings, the new CDC classification system could be simplified into three stages, stage I and II comprising the above mentioned six subgroups, and stage III comprising clinical AIDS defining categories C1, C2, and C3. These three stages correspond to different periods in the management of HIV positive patients, i.e., period of observation, period of prophylaxis, and period of treatment.Abbreviations AIDS acquired immunodeficiency syndrome - CDC Centers for Disease Control - HIV Human immunodeficiency virus Correspondence to: E.B. Helm  相似文献   
52.
In order to elucidate the effectiveness of anti-mycotics in treating seborrhoeic dermatitis, an attempt was made to isolate Malassezia from seborrhoeic lesions of patients of seborrhoeic dermatitis. The results revealed that, in male patients, 46/49 cases were positive for Malassezia furfur on the face and 30/48 cases were positive for M. furfur on the scalp. In female patients, 7/13 cases were positive for M. furfur on the face, and 6/17 cases were positive for M. furfur on the scalp. Anti-mycotic agents were excellent in 50% and good in 31% of the spore-positive cases, yielding an overall efficacy rate of 81%. In contrast, the treatment of the face with vehicle alone showed only one excellent result out of 8 cases. Although clinical improvement was rapid on the side treated with a topical corticosteroid in the half-side-test, numerous fungal elements remained. While the improvement with anti-mycotic agents was slower than that with the corticosteroid, clinical improvement became evident by the third week of administration and fungal elements disappeared.  相似文献   
53.
本文在国内首次报告了念珠状链杆菌在清洁级C57BL/6J小鼠群中的自然感染,并从临床、病理解剖、病原学及流行病学方面进行了较为详细的观察,在受检的14例发病动物中,颈部淋巴结肿大、化脓占71.4%,皮下、肺门淋巴结脓肿分别占50.0%和21.4%,多发性关节炎(包括趾、跗关节)占21.4%,子宫积脓占7.1%,从所有病灶及部分动物的血液、脾、肝、肺、肾均分离到了单一的细菌。该菌在小鼠成功地进行了急性感染实验,受感染动物出现了典型的念珠状链杆菌病的临床及病理特征,即败血症、关节炎、淤血、水肿、紫绀、结膜炎等。所分离的致病菌在病原学上也完全符合念珠状链杆菌的病原学特征。在饲养环境上与发病鼠群有密切关系的其它4个品系小鼠群,即615、BALB/c、CBA、KM,均未波感染,证明在对该菌的易感性方面存在品系差异。  相似文献   
54.
912抗肿瘤作用机理的初步探讨   总被引:2,自引:1,他引:1  
作者对912的抗肿瘤作用机理进行了初步探讨。观察到912对癌细胞的移植量以及不同的服用时间均表现出不同的抑瘤效应。将服用912后的小鼠的脾细胞与肿瘤细胞混合后再接种,肿瘤生长明显抑制。912对实验肿瘤动物的外周血白细胞分类、巨噬细胞的吞噬功能和E玫瑰花形成也有一定的影响。  相似文献   
55.
本研究评价了喷砂、氢氟酸(HF)、氢氟酸处理后涂KH-570乙醇液等方法时国产GD光固化复合树脂以及进口VIVADENT复合树脂的修补效果.结果表明:9.6%HF处理国产树脂、喷砂处理进口树脂均获得最大的修补强度,HF KH-570处理方法虽为每种材料中之最小者,但与其它修补方法间无显著性差异.  相似文献   
56.
Flecainide   总被引:1,自引:0,他引:1  
Flecainide. Flecainide is a Class IC antiarrhythmic agent whose primary electrophysiologic effect is a slowing of conduction in a wide range of cardiac tissues. It is well absorbed and effective in suppressing isolated premature ventricular contractions (PVCs) or nonsustained ventricular arrhythmia but has only a modest efficacy when electrophysiologic testing is used as an endpoint. Us adverse effect on mortality in the CAST trial suggested a propensity to proarrhythmia-a phenomenon to which the Class IC agents appear particularly prone. Despite the applicability of the CAST study only to patients with a prior myocardial infarction, there has been a shift away from flecainide in ventricular arrhythmia, but the low noncardiac side effect profile of the agent allows for its continued use in a wide variety of supraventricular arrhythmias. ( J Cardiovasc Electrophysiol, Vol. 5, pp. 964–981. November 1994 )  相似文献   
57.
新螯合剂对铍中毒的解毒和促排效果   总被引:2,自引:0,他引:2  
本文报道了新蟹合剂8102,S186对铍中毒动物的解毒和促排作用,并与811,DTPA 进行比较,大、小鼠BeSO_4中毒后,给予不同剂量的螯合剂解毒,结果表明,8102,S186对铍中毒动物的解毒效果均优于后两种,对大鼠的解毒作用8102优于S186,但S186对小鼠的解毒作用优于8102。螫合剂对大鼠BeSO_4染毒的排铍效果实验结果证明:各螫合剂的排铍效果强弱:8102>S186>811>DTPA。8102和S186对大鼠急性铍中毒有明显的排铍效果,若染毒前1h 或延迟4h 给药,仍有显著的排铍作用,但低于即刻用药组的效果。8102对亚急性染毒带铍状态亦有较高促排铍的作用。  相似文献   
58.
以Fe~(3+)代替Pd-C和Raney Ni为催化剂、水合肼为供氢体、3,3′-二硝基-4,4′-二氨基二苯醚为受氢体、甲醇为溶剂,进行催化转移氢化反应,产物3,3′,4,4′-四氨基二苯醚(TADPO)质量好,得率可达80%。此外,还对反应温度、时间、以及水合肼、催化剂、溶剂用量,水合肼浓度、催化剂重复使用等影响因素进行了研究,获得了较佳工艺条件。本法制得的TADPO与均苯四甲酸二酐缩聚可制得性能良好的聚眯唑吡咙。  相似文献   
59.
Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent.  相似文献   
60.
淫羊藿总黄酮对肾上腺素β_1受体的特异性阻断作用   总被引:2,自引:0,他引:2  
为探讨淫羊藿总黄酮(TFE)对肾上腺素受体的作用,本实验用离体兔心房肌、主动脉及豚鼠气管观察了TFE对肾上腺素全体的作用,结果TFE(0.13g/L)抑制心房肌肌力和频率,并使异丙肾上腺素(ISO)对心房肌正性频率作用的量效曲线平行右移,但无钙拮抗作用及M受体激动效应,且不影响ISO对豚鼠气管条的负性肌力作用及去甲肾上腺囊(NE)对兔主动脉条的收缩作用。提示TFE选择性阻断肾上腺素β_1受体。  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