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   5580篇
  免费   515篇
  国内免费   19篇
耳鼻咽喉   52篇
儿科学   195篇
妇产科学   129篇
基础医学   684篇
口腔科学   36篇
临床医学   793篇
内科学   966篇
皮肤病学   136篇
神经病学   322篇
特种医学   615篇
外科学   696篇
综合类   173篇
一般理论   3篇
预防医学   559篇
眼科学   43篇
药学   383篇
肿瘤学   329篇
  2022年   33篇
  2021年   78篇
  2020年   58篇
  2019年   80篇
  2018年   101篇
  2017年   53篇
  2016年   81篇
  2015年   80篇
  2014年   146篇
  2013年   172篇
  2012年   240篇
  2011年   283篇
  2010年   134篇
  2009年   141篇
  2008年   251篇
  2007年   257篇
  2006年   219篇
  2005年   263篇
  2004年   197篇
  2003年   165篇
  2002年   177篇
  2001年   144篇
  2000年   173篇
  1999年   157篇
  1998年   80篇
  1997年   81篇
  1996年   99篇
  1995年   98篇
  1994年   91篇
  1993年   86篇
  1992年   136篇
  1991年   125篇
  1990年   125篇
  1989年   127篇
  1988年   126篇
  1987年   126篇
  1986年   125篇
  1985年   127篇
  1984年   98篇
  1983年   87篇
  1982年   62篇
  1981年   34篇
  1980年   42篇
  1979年   52篇
  1978年   50篇
  1977年   36篇
  1976年   52篇
  1975年   36篇
  1974年   36篇
  1971年   29篇
排序方式: 共有6114条查询结果,搜索用时 15 毫秒
81.
82.
BackgroundPreoperative carbohydrate loading is a component of Enhanced Recovery After Surgery (ERAS) protocols, but there is limited literature in bariatric surgery patients.ObjectivesThe objective of this study was to characterize the impact of preoperative carbohydrate loading on postoperative bariatric surgery outcomes.SettingUniversity Hospital.MethodsPatients undergoing a primary minimally invasive Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) between 2018 and 2020 were randomized to standard management or intervention. Standard management patients were nothing by mouth (NPO) after midnight prior to surgery. Intervention patients consumed 2 carbohydrate drinks: 1 the night before and another 3 hours prior to surgery. Primary outcomes analyzed included postoperative nausea and vomiting (PONV), length of stay, and overall complications.ResultsIn total, 134 patients were analyzed: 64 intervention (47.8%) and 70 (52.2%) standard. In the end, 7% and 15% of patients were lost to follow-up at 6-weeks and 3-months, respectively. There was no statistically significant difference in length of stay (2.0 ± 1.2 vs 2.1 ± .9 d; P = .65) or postoperative outcomes between the 2 groups. There were no episodes of aspiration among the intervention group. Among RYGB patients, intervention patients had a shorter duration of nausea compared with standard patients. There was no significant difference in glycemic control among patients with and without diabetes.ConclusionsPreoperative carbohydrate drinks can be administered to bariatric surgery patients without significant risks. Carbohydrate loading preoperatively can decrease the duration of PONV in RYGB patients. Carbohydrate drinks can be safely included in bariatric ERAS protocols for patients with and without diabetes, although the benefits remain unknown.  相似文献   
83.
BackgroundTezacaftor (TEZ)/ivacaftor (IVA) is an approved CFTR modulator shown to be efficacious and generally safe and well tolerated in people ≥12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous for the F508del-CFTR mutation and a residual function mutation. Although previous studies with IVA alone showed clinical benefits in people with CFTR gating mutations, TEZ/IVA has not yet been evaluated in a Phase 3 study of participants heterozygous for F508del-CFTR and a gating mutation (F/gating genotypes). Here, we present results from a randomized, double-blind, IVA-controlled, parallel-group, Phase 3 study assessing the efficacy, safety, and pharmacokinetics (PK) of TEZ/IVA in participants ≥12 years of age with F/gating genotypes.MethodsEnrolled participants entered a 4-week IVA run-in period to create a stable IVA baseline. Participants were then randomized to receive IVA or TEZ/IVA for 8 weeks in an active comparator treatment period (ACTP). The primary endpoint was absolute change in percent predicted forced expiratory volume in 1 second (ppFEV1). Key secondary endpoints were relative change in ppFEV1 and absolute change in CF Questionnaire–Revised respiratory domain score. Secondary endpoints included absolute change in sweat chloride (SwCl) concentration, PK parameters, and safety. All endpoints except PK parameters and safety were assessed from baseline through Week 8.ResultsSixty-nine participants (92.0%) in the IVA group and 75 participants (98.7%) in the TEZ/IVA group completed treatment. No improvements were seen in efficacy endpoints from baseline at the end of the IVA run-in period through the end of the ACTP in the IVA group. No significant differences in ppFEV1 or any key secondary endpoint were observed between the IVA and TEZ/IVA groups. SwCl concentrations decreased more in the TEZ/IVA versus IVA group during the ACTP. The safety profile and PK parameters of TEZ/IVA were consistent with those of previous studies in participants ≥12 years of age with CF.ConclusionsThis Phase 3 study showed that the dual-combination regimen of TEZ/IVA demonstrated clinical efficacy but did not have significantly greater clinical efficacy than IVA alone in participants ≥12 years of age with F/gating genotypes. However, as reported in other studies, TEZ/IVA was generally safe and well tolerated (NCT02412111).  相似文献   
84.
85.
Six new capsular types of Streptococcus suis (types 23 to 28) are described. All reference strains were isolated from diseased pigs and were morphologically and biochemically similar to previously described capsular types 1 to 22. Clear and specific reactions were obtained for each of the new capsular types with three different typing techniques; no cross-reactions were detected among them or with other S. suis capsular types. Their capsular material presented similar ultrastructural characteristics, as shown by electron microscopy, and fimbriae similar to those described for other capsular types of S. suis were observed. When untypeable field isolates were tested with antisera raised against the six new capsular types, capsular type 23 appeared to be the most prevalent, representing more than 50% of all these isolates. Most isolates were recovered from cases of pneumonia, septicemia, and meningitis. Presumptive biochemical identification described for S. suis capsular types 1 to 22 may also be used for capsular types 23 to 28.  相似文献   
86.
The automatic implantable cardioverter-defibrillator (AICD) is being used more frequently in patients with recurrent malignant arrhythmias refractive to sophisticated antiarrhythmic drug therapy. Such patients often present to emergency facilities with cardiac and/or device related complaints. Both "appropriate" and "inappropriate" AICD pulsing can result in patient adversity. For this reason AICD generator deactivation is indicated in certain clinical conditions once a controlled and properly equipped medical environment is assured. This report discusses a number of relevant emergent management issues concerning this beneficial device.  相似文献   
87.
Summary An influenza B virus was passaged in man (virus A) and then in human embryo trachea (C) and into embryonated eggs (D) or directly into eggs (B). Virus A, B, and C had the same (cell-like) haemagglutinin phenotype on reaction with selected monoclonal antibodies while D had an egg-like phenotype. The viruses were administered at a dose of 1,000 TCD50 (for MDCK cells) by intranasal inoculation to groups of 27 or 28 volunteers. Viruses A, B, and C all produced disease in six to eight volunteers, whereas D produced no illness and only four volunteers were infected. The viruses shed by the volunteers were indistinguishable from those with which they were inoculated. The haemagglutinin genes of the viruses were sequenced and changes were detected indicating amino acid substitutions at position 196–198 in the attenuated egg-grown virus D whereby a potential glycosylation site present in the other viruses was lost.  相似文献   
88.
Gill Higgins 《Inpharma》1993,869(1):5-5
Contrary to previous beliefs, the targets for antiulcer drug therapy appear to be located in the immune cells of the lamina propria. This finding calls for a revision to models of gastric acid secretion and regulation. It could also imply that researchers should look towards an immune approach to gastric ulcer prevention. However, further research is required before such a step is taken, particularly in view of the efficacy of currently-used drugs.  相似文献   
89.
The present study examined further the pharmacological specificity of the methylxanthine CNS stimulant caffeine as a discriminative stimulus in humans. Nine normal healthy volunteers (ages 19-39) were trained to discriminate between caffeine (320mg/70kg, p.o.) and placebo, using monetary reinforcement of correct letter code identification. After four training sessions, subjects were tested with the training conditions until they were >80% correct on four consecutive sessions. Then dose-effect curves were determined for caffeine (56-320mg/70kg), theophylline (56-320mg/70kg), methylphenidate (10-56mg/70kg), and buspirone (1-32mg/70kg). Seven of nine subjects met the discrimination criterion within four to nine sessions. During dose-effect curve determinations, caffeine and methylphenidate each produced dose-related increases in caffeine-appropriate responding. Theophylline produced caffeine-appropriate responding that was not dose related in a consistent manner across subjects, occasioning an average of 50% caffeine-appropriate responding at most doses tested. Buspirone produced predominantly placebo-appropriate responding. Caffeine-appropriate responding tended to be directly related to ARCI LSD scores, self-reported "bad" effects, "high", and stimulant-bad effects and inversely related to ARCI PCAG scores and sedative ratings. These results agree with non-human data and suggest that the caffeine discriminative stimulus has pharmacological specificity, in that caffeine-appropriate responding generalizes to other stimulants such as theophylline or methylphenidate, but not to non-stimulant compounds such as buspirone.  相似文献   
90.
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