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   55346篇
  免费   4747篇
  国内免费   971篇
耳鼻咽喉   293篇
儿科学   2382篇
妇产科学   853篇
基础医学   5139篇
口腔科学   1025篇
临床医学   7568篇
内科学   8193篇
皮肤病学   706篇
神经病学   862篇
特种医学   856篇
外国民族医学   1篇
外科学   6866篇
综合类   8194篇
现状与发展   7篇
预防医学   10419篇
眼科学   306篇
药学   4980篇
  51篇
中国医学   1103篇
肿瘤学   1260篇
  2024年   187篇
  2023年   1032篇
  2022年   2073篇
  2021年   2648篇
  2020年   2710篇
  2019年   2138篇
  2018年   2067篇
  2017年   1992篇
  2016年   2128篇
  2015年   2345篇
  2014年   3909篇
  2013年   4371篇
  2012年   3924篇
  2011年   4017篇
  2010年   2866篇
  2009年   2578篇
  2008年   2368篇
  2007年   2409篇
  2006年   2271篇
  2005年   1993篇
  2004年   1623篇
  2003年   1384篇
  2002年   1005篇
  2001年   907篇
  2000年   742篇
  1999年   698篇
  1998年   562篇
  1997年   512篇
  1996年   443篇
  1995年   425篇
  1994年   395篇
  1993年   328篇
  1992年   297篇
  1991年   277篇
  1990年   201篇
  1989年   208篇
  1988年   157篇
  1987年   132篇
  1986年   103篇
  1985年   139篇
  1984年   86篇
  1983年   67篇
  1982年   77篇
  1981年   64篇
  1980年   40篇
  1979年   41篇
  1978年   24篇
  1977年   25篇
  1976年   33篇
  1975年   15篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
本文用前瞻性连续检测方法,对269例患者作胃粘膜HP检测,且同步对消毒前后的胃镜、有关器械和操作者手套采样,作HP检测。结果发现,消毒前镜端(含弯曲部)、活检钳、清洁刷、器械管道插口和操作者手套采样标本的HP阳性率分别达69.51%、73.60%、81.62%、87.73%和97.72%。目前常规的清洗消毒虽能清除HP对胃镜的大部分污染,但还存在一些易忽视的环节,这可能在检查中引起医源性感染,应予高度重视。  相似文献   
92.
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   
93.
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   
94.
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   
95.
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   
96.
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   
97.
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   
98.
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   
99.
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   
100.
目的了解截瘫患者医院感染的病原菌对药物敏感情况. 方法回顾分析我院自1996年9月~2003年11月,316例截瘫患者的有关临床资料. 结果 98例患者发生医院感染,医院感染率为31.01%,感染部位主要以呼吸道、皮肤软组织、手术切口、泌尿道感染为多;医院感染的病原菌主要是条件致病菌,以G-菌为主.结论医护人员必须严格无菌操作,根据细菌药敏结果合理选用抗菌药物,加强营养,提高患者机体抵抗力.  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