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   54483篇
  免费   4808篇
  国内免费   944篇
耳鼻咽喉   318篇
儿科学   2509篇
妇产科学   877篇
基础医学   5249篇
口腔科学   1165篇
临床医学   7053篇
内科学   8261篇
皮肤病学   706篇
神经病学   940篇
特种医学   895篇
外国民族医学   1篇
外科学   5937篇
综合类   8213篇
现状与发展   7篇
预防医学   10143篇
眼科学   300篇
药学   4670篇
  46篇
中国医学   1819篇
肿瘤学   1126篇
  2024年   116篇
  2023年   944篇
  2022年   1568篇
  2021年   2566篇
  2020年   2632篇
  2019年   2113篇
  2018年   2006篇
  2017年   2024篇
  2016年   2195篇
  2015年   2301篇
  2014年   3898篇
  2013年   4351篇
  2012年   3832篇
  2011年   3903篇
  2010年   2782篇
  2009年   2548篇
  2008年   2368篇
  2007年   2454篇
  2006年   2325篇
  2005年   1987篇
  2004年   1649篇
  2003年   1412篇
  2002年   1031篇
  2001年   929篇
  2000年   779篇
  1999年   706篇
  1998年   564篇
  1997年   521篇
  1996年   452篇
  1995年   433篇
  1994年   401篇
  1993年   338篇
  1992年   306篇
  1991年   280篇
  1990年   201篇
  1989年   214篇
  1988年   160篇
  1987年   138篇
  1986年   102篇
  1985年   146篇
  1984年   94篇
  1983年   68篇
  1982年   86篇
  1981年   65篇
  1980年   49篇
  1979年   54篇
  1978年   30篇
  1977年   27篇
  1976年   37篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL.  相似文献   
62.
63.
64.
Although there are effective antibacterial agents against plague, newer antibacterial agents have been developed which show more potent activity against other bacterial organisms, but have not been tested againstYersinia pestis. A strain ofYersinia pestis was selected (no. 22; National Institute of Infectious Diseases, Tokyo, Japan) that caused a systemic infection in mice.Y. pestis no. 22 was intraperitoneally inoculated into DDY-strain mice, and 13 oral or 6 injectable antibacterial drugs given to the infected mice at varying doses 1 and 24 hours after infection. Levofloxacin, sparfloxacin and ofloxacin were the most effective oral agents against the infection, and prulifloxacin and pazufloxacin were also effective but to a lesser extent. Also, gentamicin and arbekacin were the most potent injectable antibacterial agents againstY. pestis. These results suggest that there are several new drugs, both oral and injectable, which exert excellent in vivo antibacterial activity against a mouse infection model and may be useful for the clinical treatment of plague.  相似文献   
65.
目的 探讨难治性支气管—肺部感染(难治组)衣原体、支原体两种病原体的表达。方法 应用ELISA法检测了29例难治性支气管—肺部感染两种非典型病原体急性感染指标,衣原体抗体IgM、支原体抗体IgM及冷凝集实验,并常规细菌学检查,与同期住院的普通性下呼吸道感染(普通组)40例,门诊及住院的急性上呼吸道感染(上感组)30例进行比较。结果 难治组衣原体急性感染率68.9%,显著高于普通组、上感组,上感组最低;支原体急性感染率难治组34、5%,显著高于普通组、上感组;衣原体混合支原体、衣原体混合其他致病菌感染均显著高于普通组和上感组。结论 难治性下呼吸道感染中衣原体、支原体感染率较高,且易与多种病原体混合感染,衣原体的慢性感染可能是难治感染的重要原因。  相似文献   
66.
We assessed the efficacy of a government-sponsored mass protection program in Osaka, Japan, for perinatal HBV infection in infants born to HBeAg positive HBV carrier mothers. We also evaluated the impact of optional follow-up procedures in such infants, including an evaluation of anti-HBs response and a booster dose of HBV vaccine for poor responders. The results demonstrated that this mass protection program protected 94.4% of the infants from perinatal HBV infection in the Osaka area. However, the proportion of infants with an unprotective level of anti-HBs was higher in the standard group than in the follow-up group both at 1.0 and 1.5 years of age, which was also the case for HBV events. Furthermore, the present study showed that a booster dose of vaccine in poor responders was very effective in promoting an anti-HBs response. In conclusion, we recommend that a follow-up blood test to confirm a response of anti-HBs to HBV vaccine should be performed at 4–8 weeks after the third injection of HBV vaccine in infants born to HBeAg positive HBV carrier mothers. We also recommend that a booster injection of HBV vaccine should be immediately given to poor responding infants who otherwise are at a considerable risk of developing HBV infection in late infancy.  相似文献   
67.
刘国莲  程雪涛  鲁军 《宁夏医学杂志》2007,29(12):1069-1071
目的探讨肾移植术后肺部感染的诊断与治疗。方法对21例肾移植术后肺部感染的病原体及其致病特点、诊断、治疗等临床资料进行分析。结果21例肾移植术后肺部感染患者中单纯细菌感染6例(28.57%),真菌感染2例(9.52%),巨细胞病毒(CMV)感染2例(9.52%),结核菌感染1例(4.76%),混合感染9例(42.86%),病原体不清1例。2例予以呼吸机辅助治疗。19例治愈,治愈率为90.48%,2例直接死于肺部感染。结论肾移植术后肺部感染患者应早期行病原学诊断,积极有效抗感染,及时调整免疫抑制方案。  相似文献   
68.
This article describes the association between previous infection and/or vaccination and the development of optic neuritis (ON) in 18 children. Ten of these children subsequently developed clinically definite multiple sclerosis (MS), while in 8 patients a clinically definite etiology could not be confirmed. Vaccination preceded the first ON attack in 6 patients, all but one of whom subsequently developed MS. It also preceded subsequent demyelinating events in 6 patients. Ten of the patients had a bacterial or viral infection within the 2 weeks prior to the first symptoms of ON. Intrathecal antibody synthesis against 2 or more viruses could be shown in 5 out of 8 patients studied; 5 out of 6 patients had oligoclonal antibodies in CSF and 12 out of 16 patients a high IgG index. Neither intrathecal antibody synthesis against 2 or more viruses nor elevated IgG indexes could be found in the control patients. Measles and mumps occurred at a significantly later age in the children who subsequently developed MS than in the control children, and these patients had significantly more events that might have impaired the blood-brain barrier than the controls. These results indicate that immunological events leading to MS may be triggered during childhood. Vaccination and infection often precede ON in childhood. Intrathecal viral antibody production can occur already in childhood at the time of the first symptoms of MS.  相似文献   
69.
目的:了解检验专业学生入学时和毕业前的HBsAg感染率的情况,找出引起检验专业学生HBsAg感染率升高的原因,为制定切实有效的预防措施打下牢固的基础。方法:对该专业学生进行入学时和毕业前采用ELISA法检查HB-sAg。结果:3届学生入学时HBsAg感染率差异无显著性,性别间HBsAg感染率差异无显著性,社区医学专业学生HBsAg感染率入学时与毕业前比较差异无显著性,而检验专业学生HBsAg感染率入学时与毕业前比较差异有显著性。结论:部分检验专业学生没有树立正确的安全范意识,自我保护能力较差,从而造成了自身的感染。  相似文献   
70.
The presence of free immunoglobulin light chains (FLCs) in the cerebrospinal fluid (CSF) and sera of patients with human immunodeficiency virus-1 (HIV-1) infection, multiple sclerosis (MS), and neurologically healthy control individuals was investigated by paying special attention to ensure that only truly free light chains would be detected. The FLCs were extracted by specifically binding them to Sepharose-coupled anti-FLC monoclonal antibodies, and thereafter they were electrophoresed and immunoblotted with monoclonal antibodies to both light chain (LC) isotypes. A frequent occurrence of kappa and lambda FLCs was found in both CSF and sera of HIV-1 infected patients. In HIV-1 infection and in MS, the frequency of FLCs of the CSF was equal. In healthy controls, only occasional weak FLCs were observed in either CSF or serum. FLC bands of the CSF from patients with HIV-1 infection tended to be more intensive than those of the appropriately diluted sera. Both intrathecal synthesis of FLCs and their transudation from sera through the impaired blood-brain barrier (BBB) may contribute to this. Increasing severity of general HIV-1 infection was accompanied by an increase of FLC intensity in sera. A qualitative demonstration of FLC in the CSF may be meaningful only in the absence of altered BBB function.  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