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   56301篇
  免费   4822篇
  国内免费   1029篇
耳鼻咽喉   450篇
儿科学   2396篇
妇产科学   886篇
基础医学   5677篇
口腔科学   1427篇
临床医学   7203篇
内科学   8170篇
皮肤病学   702篇
神经病学   1240篇
特种医学   1470篇
外国民族医学   1篇
外科学   6808篇
综合类   8011篇
现状与发展   8篇
一般理论   1篇
预防医学   10389篇
眼科学   398篇
药学   4427篇
  45篇
中国医学   1214篇
肿瘤学   1229篇
  2024年   172篇
  2023年   1020篇
  2022年   2010篇
  2021年   2646篇
  2020年   2650篇
  2019年   2115篇
  2018年   2062篇
  2017年   2029篇
  2016年   2151篇
  2015年   2334篇
  2014年   3801篇
  2013年   4334篇
  2012年   3759篇
  2011年   3866篇
  2010年   2794篇
  2009年   2608篇
  2008年   2487篇
  2007年   2521篇
  2006年   2393篇
  2005年   2098篇
  2004年   1736篇
  2003年   1537篇
  2002年   1107篇
  2001年   1000篇
  2000年   821篇
  1999年   774篇
  1998年   619篇
  1997年   566篇
  1996年   501篇
  1995年   485篇
  1994年   444篇
  1993年   364篇
  1992年   328篇
  1991年   305篇
  1990年   214篇
  1989年   233篇
  1988年   183篇
  1987年   155篇
  1986年   119篇
  1985年   160篇
  1984年   108篇
  1983年   78篇
  1982年   100篇
  1981年   75篇
  1980年   57篇
  1979年   56篇
  1978年   32篇
  1977年   38篇
  1976年   46篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
作者于1987年2月16日~1988年2月15日在四川五个点211 639人群中监测急性病毒性肝炎。其发病率为167.74/10万,其中甲型肝炎占24.51%;乙型肝炎占38.31%;非甲非乙型肝炎占24.51%,EB病毒和巨细胞病毒所致肝炎各占3.38%;混合感染占5.92%。病毒性肝炎中有14.93%重叠感染。发病高峰在春季。发病率,男:女=1.75:1。甲型肝炎20岁以下年龄组、乙型肝炎20~39岁年龄组的发病率明显高于其他年龄组,非甲非乙型较分散,5~19岁相对多一些,其他型别年龄组间无明显差异。355例急性病毒性肝炎患者中43.9%有接触史,36.6%有注射史。  相似文献   
102.
本实验对腹腔感染造成多器官衰竭的动物观察了不同全静脉营养配方在代谢支持中的作用。结果显示:在兔感染性多器官衰竭早期,实行代谢支持能够不同程度地增加体重、促进蛋白质合成和扭转负氮平衡。适当减低糖供给的非蛋白热量可以减轻应激反应,增加氮保留和改善肺功能。供给氨基酸过多则增加应激反应、增加尿氮排出和加重呼吸负担。  相似文献   
103.
There are significant variations among countries in the incidence of brain abscess. We report here 26 cases of brain abscess treated at the Neurosurgery Department of King Faisal University and Dammam Central Hospital Saudi Arabia over a six year period (1982–1988). This is 2.3% of total admissions to the two neurosurgery departments serving a population of approximately 1.2 million in the same period.Young males were most often affected (M/F ratio 3.3:1; 31% were less than 15 years old, 46% aged between 15–39 years, and 23% older than 40 years). Streptococcus was found to be the most common microorganism (38.4%). Mixed infection was seen in 15.3%, and sterile abscesses were found in 11.5% of the patients after aerobic and anaerobic cultures of the pus. Chronic otitis media and paranasal sinusitis predisposed the patients to abscess formation in 57.6% of the cases. The temporo-parietal area was the commonest site. Epilepsy was a complication in 30.7% of our patients, and the mortality rate was 15.3%.  相似文献   
104.
We describe the pathological findings in two fatal cases of neonatal infection with herpes simplex virus. One had an encephalitis caused by herpes simplex virus type 2 (HSV-2); the other had a disseminated infection with herpes simplex virus type 1 (HSV-1). Confirmation of the diagnosis was obtained by use of the polymerase chain reaction to amplify viral DNA from paraffin sections of autopsy tissues. By using primers which amplify fragments of the HSV-1 thymidine kinase gene and HSV-2 glycoprotein gene respectively it was possible to discriminate between infection with HSV-1 and HSV-2. In contrast, immunohistochemistry and in situ hybridization using commercially available reagents did not distinguish between HSV-1 and HSV-2 infection. However, immunohistochemistry and in situ hybridization are probably more reliable than the polymerase chain reaction for assessment of the distribution of virus in different tissues.  相似文献   
105.
The aim of the present study was to determine whether the Ity gene, which controls the resistance to S. typhimurium infection in mice, also governs the resistance to S. abortusovis, a serotype specific for goat and sheep. During either i.v. or i.p. infection, BALB/c mice (Itys) were not able to control the growth of S. abortusovis and eventually died from infection. In contrast CBA (Ityr) or (C.CB)F1 (Ityr/s) mice were able to control the growth of these bacteria. Using congenic C.D2 Ityr mice, we found that the gene controlling resistance to S. abortusovis was tightly linked to the Ity gene on chromosome 1. Furthermore, in the spleen and the liver of backcross BALB/c x (CBA x BALB/c) mice, the S. abortusovis resistance phenotype cosegregated with the two alleles of the Len-1 gene, a gene tightly linked to the Ity gene. By contrast, in these backcross mice, the level of infection of the peritoneal cavity, the site of inoculation, did not correlated with the Len-1 phenotype of the animal. These results provide evidence that after i.p. inoculation the control of S. abortusovis growth in the spleen and the liver is controlled by the Ity gene, but also suggest that additional gene(s) regulate the number of bacteria at the site of inoculation.  相似文献   
106.
本文分析了20例有明确蛛网膜下腔出血病史的正常颅压脑积水患者的临床表现,其中有智能、步态障碍、尿失禁三联征典型表现者占11例(55%),有其中二个症状者4例。CT是诊断脑积水的首选检查。本文还结合文献对正常颅压脑积水的发生发展,与之有关的因素及临床表现进行讨论。  相似文献   
107.
从34例牙髓根管感染中共分离出厌氧菌118株,经菌属分类依次为消化链球菌属,拟杆菌属,梭杆菌属,放线菌属,韦荣氏球菌属和珠网菌属,其中前3属为77株,分离率为65.3%,这一结果显示该3属细菌与极管感染有密切关系,是牙髓根管感染的优势菌。  相似文献   
108.
从1985年4月到1986年4月对361名孕妇进行的乙型肝炎流行病学横断面研究以及196名产妇一年随访研究的结果表明,361例孕妇的HBsAg阳性率为2.5%,抗-HBs阳性率为23.8%,抗-HBc阳性率为22.1%,HBV总感染率为31.3%;抗-HBs阳性、抗-HBs和抗-HBc共存阳性者占总阳性者的76.1%,说明人群感染HBV后大多产生了免疫力.1986年4月复查了196例产妇,133名在1985年HBV标记阴性者中有6人获得了HBV标记,HBV新感染率为4.5%;1例为急性乙型肝炎病人,5例为亚临床感染.HBV新感染者的感染途径不明,但医源性传播不能排除.1986年检查的148对夫妇中,男性HBsAg阳性率是女性的3.1倍(6.1%对2.0%),男性单独抗-HBc阳性率是女性的2.3倍(6.1%对2.7%),抗-HBs、抗-HBs和抗-HBc共存以及HBV感染率男女性间都无显著差异.  相似文献   
109.
Summary We report a case of non-Hodgkin's lymphoma with CNS involvement confined to the epidural space causing cranial suture diastasis. Cerebrospinal fluid and bone marrow were normal. Two cases only of cranial epidural lymphoma have been reported in the literature; in both cases, the leptomeninges were also involved but without suture diastasis.  相似文献   
110.
Canine Distemper Virus (CDV) produces an encephalitis in dogs that varies with viral strain. We have studied the cell tropisms of two virulent strains (CDV-SH and CDV A75-17) and an attenuated strain, Rockborn (CDV-RO), in cultured canine brain cells. Infected cell types were identified by double immunofluorescent labeling of specific cell markers and viral antigens. All viral strains studied produced infection in astrocytes, fibroblasts, and macrophages. Neurons were not infected by CDV A75-17 but were rapidly infected by CDV-SH and CDV-RO. Multipolar oligodendrocytes were very rarely infected by any of the virus strains. In contrast, a morphologically distinct subset of bipolar oligodendrocytes were commonly infected by CDV-SH and CDV-RO. The kinetics of infection in the astrocytes, oligodendrocytes, neurons, and macrophages varied between strains. Both CDV-SH and CDV-RO rapidly infected bipolar oligodendrocytes, astrocytes, neurons, and macrophages by 14 days post infection while infection by CDV A75-17 was delayed until after 28-35 days post infection. The differences in the growth kinetics and cell tropisms for some brain cells, exhibited by the three viral strains examined in this in vitro study, may relate to the different CNS symptoms that these strains produce in vivo.  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