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   69189篇
  免费   5793篇
  国内免费   1350篇
耳鼻咽喉   443篇
儿科学   3605篇
妇产科学   1045篇
基础医学   7205篇
口腔科学   1065篇
临床医学   9604篇
内科学   11499篇
皮肤病学   795篇
神经病学   1318篇
特种医学   1375篇
外国民族医学   1篇
外科学   6916篇
综合类   10126篇
现状与发展   13篇
预防医学   12527篇
眼科学   327篇
药学   5648篇
  83篇
中国医学   1454篇
肿瘤学   1283篇
  2024年   210篇
  2023年   1293篇
  2022年   2790篇
  2021年   3813篇
  2020年   3501篇
  2019年   2516篇
  2018年   2408篇
  2017年   2456篇
  2016年   2678篇
  2015年   2745篇
  2014年   4419篇
  2013年   5154篇
  2012年   4303篇
  2011年   4431篇
  2010年   3254篇
  2009年   3045篇
  2008年   2807篇
  2007年   2997篇
  2006年   2954篇
  2005年   2624篇
  2004年   2369篇
  2003年   2257篇
  2002年   1309篇
  2001年   1213篇
  2000年   967篇
  1999年   901篇
  1998年   764篇
  1997年   719篇
  1996年   604篇
  1995年   595篇
  1994年   545篇
  1993年   477篇
  1992年   454篇
  1991年   399篇
  1990年   307篇
  1989年   310篇
  1988年   258篇
  1987年   222篇
  1986年   174篇
  1985年   239篇
  1984年   157篇
  1983年   111篇
  1982年   124篇
  1981年   105篇
  1980年   71篇
  1979年   63篇
  1978年   53篇
  1977年   43篇
  1976年   48篇
  1975年   22篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
急性传染性非典型肺炎的影像表现   总被引:1,自引:0,他引:1  
目的探讨急性传染性非典型肺炎(SARS)的X线表现及变化规律.方法回顾性分析临床诊断SARS的61例患者,对发病后的一系列胸片和CT影像进行统计分析.结果患者以发热为最早起病症状,88.5%患者在起病1周内肺部出现肺局灶性斑片状模糊影,并迅速扩大.2周内病变达高峰,有57.4%患者两肺大部分肺野受累,病情重.83.6%患者在5周内肺部阴影逐渐消散.在恢复期16例CT扫描中,有13例显示肺部遗留纤维化病灶.有6例患者合并感染,病期延长,4例死亡.结论SARS早期出现肺部炎性改变,发展迅速,大部分两肺受累,重症比例高,易致肺纤维化.  相似文献   
102.
BACKGROUND: Frequent infection in infancy and early childhood has been hypothesized to explain the low prevalence of asthma and other atopic disease among children in developing countries (the so-called 'hygiene hypothesis'), but the low prevalence in Eastern Europe remains unexplained. OBJECTIVE: To test the hygiene hypothesis in the Republic of Belarus by examining the relationship between gastrointestinal (GI) and respiratory infection and two potentially atopic outcomes in the first 12 months of life: atopic eczema and recurrent wheeze. METHODS; We carried out two case-control studies nested within a large (n=17 046) randomized trial in Belarus, with cases defined as (1) first occurrence of atopic eczema (n=819) and (2) second episode of wheezing (n=112). Incidence density sampling was used to select four matched controls born within 1 month at the same hospital as the case. Exposure was defined as one or more episodes of GI or respiratory infection (examined separately) with onset >7 days before onset of the case's atopic outcome. Analyses controlled for family atopic history, duration of exclusive breastfeeding, sex, birth weight, maternal education, and (for recurrent wheeze) maternal smoking. RESULTS: For atopic eczema, prior GI infection occurred in 7.4% of cases vs. 6.0% of controls [adjusted OR=1.27 (0.94-1.72)] and prior respiratory infection in 35.2% vs. 32.6% [adjusted OR=1.14 (95% CI=0.94-1.37)]. For recurrent wheeze, prior GI infection occurred in 9.8% of cases vs. 7.4% of controls [adjusted OR=1.30 (0.60-2.82)]. CONCLUSION: Our results do not support the hypothesis that infection protects against atopic eczema or recurrent wheezing in the first 12 months of life.  相似文献   
103.
目的:分析某医院SARS疫情的发生、发展及控制过程,为疫情控制提供一定的参考依据。方法:依照卫生部推荐的统一个案调查表和临床诊断标准,描述疫情的三间分布以及发放防护用品的数量与病例数的关系。结果:某医院疫情暴发曲线由3个暴发高峰组成,前两个峰较大,后一个峰较小,呈散发。提示病例传染共形成“三代”流行。结论:采用严密的综合防护措施,能够彻底控制SARS疫情在医院的暴发。  相似文献   
104.
刘文英  高欢 《中国民康医学》2004,16(12):731-732
目的:了解精神科住院患者医院感染情况,以利采取切实可行的预防控制措施,降低感染率。方法:对我院两年半间住院患者进行有关医院感染的调查,逐份查阅原始记录,填写统一表格,将所得资料进行相关分析。结果:医院感染72例,感染率为4.75%;感染多发生在20~29岁和30—39岁组:精神分裂症为医院感染例数最多的病种(占68.06%);皮肤及软组织和下呼吸道感染为主要感染部位,分别为23.61%和22.22%;男女两性在年龄和病程方面差异均无显著性。结论:预防及控制精神病患者的医院感染应从病人初入院时即开始;在积极控制精神症状的同时,采取多方面措施,尽可能去除医院感染的易感因素;合理规范使用抗生素,增强患者体质等,这些均有助于预防及控制医院感染。  相似文献   
105.
Abstract Closed suction drainage systems are commonly used in orthopaedic surgery, particularly in joint arthroplasty. The rationale for the use of drains is a theoretical reduction of wound haematomas and infection. However the benefit of using drains after total hip or knee arthroplasty is controversial. Several reports have shown that the use of drains does not reduce infection and morbidity and is an unnecessary and potentially dangerous practice. In fact most studies highlighted that at best their use appears to make no difference to important clinical outcomes. Recently a metaanalysis raised the question about the usefulness of closed suction drainage again, concluding that it has no major benefits. The purpose of this study was to review the evidences available concerning the utility of closed suction drainage outlining that this practice is not supported by clinical evidence.  相似文献   
106.
目的比较山莨菪碱联合无创正压面罩通气(654-2+NIPPV)和传统机械通气(CMV)治疗急性呼吸窘迫综合征(ARDS)的临床效果,评估山莨菪碱联合无创正压通气在ARDS治疗中的作用。方法将各种原因所致ARDS患者42例随机分为654-2+NIPPV组(21例)和CMV组(21例),在给予病因治疗同时分别实施654-2+NIPPV和CMV。观察分析两组患者在治疗过程中动脉血气变化、并发症的发生率及治疗效果。结果654-2+NIPPV组有8例(38.1%)治疗失败转为气管插管实行CMV,其中6例(28.6%)死亡。CMV组死亡7例(33.3%),两组病死率无显著差异(P〉0.05)。两组治疗有效的患者在分别接受654-2+NIPPV和CMV治疗后1h和6h动脉血气有相似的显著改善。654-2+NIPPV组患者机械通气时间和住院时间短于CMV组(P〈0.05)。654-2+NIPPV组的并发症发生率低于CMV组(P〈0.05)。结论在经过选择的ARDS患者中,应用654-2+NIPPV治疗的临床效果与CMV相似。实施654-2+NIPPV可缩短机械通气和住院时间,减少并发症。654-2+NIPPV可作为经过选择的ARDS患者首选的通气支持治疗手段。  相似文献   
107.
The role of Chlamydia pneumoniae in 110 Sudanese children with signs of acute lower respiratory tract infections (ALRI) was investigated. Four (3.6%) had evidence of C. pneumoniae infection, of whom 3 were culture-positive, while 1 had an antibody response suggesting a recent infection. IgG antibodies at a titer of ≥1:32 to C. pneumoniae, Chlamydia psittaci and Chlamydia trachomatis were detected in 27 (24.5%), 27 (24.5%) and 7 (6.4%) of the 110 ALRI cases, respectively. C. pneumoniae, C. trachomatis or C. psittaci were not detected in nasopharyngeal secretions from any of 110 patients when fluorescence-labeled specific monoclonal antibodies were used. In a seroepidemiological survey, 318 healthy Sudanese persons aged between 1 month and 67 years were studied for C. pneumoniae antibodies.  相似文献   
108.
目的:回顾分析75例严重急性呼吸综合症(SARS)病例,探讨该病影像学表现及其与临床治疗有关的问题。方法:全部75例患者均行胸片检查,一般隔日行影像追踪复查。结果:胸部X线表现为肺实质渗出病灶为主,肺内网状改变及肺门片块影较少。影像表现与临床病程有一定关系。结论:胸部影像表现以肺实质渗出病灶较常见。胸片检查是进行本病诊断和评估病程及疗效的重要方法。  相似文献   
109.
介绍了我院1993年7月1日~1993年12月20日出院的1031例病人医院感染病率的监测分析,半年中感染率为8.4%,妇产科疗区发病率高于外科疗区,感染部位以泌尿道、下呼吸道、手术伤口为最多,侵袭性操作及易感因素引起的感染在感染病例中分别占40.2%和59.8%。  相似文献   
110.
Measurements of respiratory mechanics are frequently made in ventilated infants and children. Esophageal pressure measurements (Pes using a balloon on a catheter have been used to partition the respiratory mechanics into lung and chest wall components. Appropriate positioning of this balloon is crucial to obtain accurate estimates of pleural pressure. Traditionally, in spontaneously breathing subjects the balloon position is assessed with an occlusion test. In ventilated subjects, it is not always possible to perform an occlusion test prior to paralysis, and even if such a test is performed it may not be relevant under conditions of positive pressure ventilation. We have assessed a positive pressure occlusion test that is suitable for paralyzed subjects. By occluding the airway opening and applying gentle pressure to the abdomen or rib cage, positive swings in pressure can be measured by both Pes and airway opening pressure (Pao). We compared traditional occlusion tests measured in 16 spontaneously breathing puppies to the positive pressure occlusion test performed after paralysis. In 2 pups we were unable to obtain a reasonable traditional occlusion test (>15% difference between Pes and Pao) but we obtained 10 traditional occlusion tests in each of the remaining 14 pups (2.1–14 kg). In 11 of these animals Ape, was within 10% of Pao. This compared well to positive pressure occlusion test using abdominal pressure performed after paralysis, where Apes was within 10% of ΔPao in 10 animals. In 9 of these pups occlusion tests were also performed by applying pressure on the rib cage, where ΔPes was within 10% of ΔPao in 6 animals. These results suggest that it is possible to perform accurate occlusion tests in paralyzed subjects by abdominal or rib cage compression with the airway occluded. Pediatr Pulmonol. 1994; 17:56–62. © 1994 Wiley-Liss, Inc.  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