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   2314篇
  免费   157篇
  国内免费   37篇
耳鼻咽喉   14篇
儿科学   67篇
妇产科学   12篇
基础医学   314篇
口腔科学   50篇
临床医学   197篇
内科学   534篇
皮肤病学   28篇
神经病学   108篇
特种医学   243篇
外科学   284篇
综合类   159篇
一般理论   3篇
预防医学   98篇
眼科学   44篇
药学   130篇
中国医学   2篇
肿瘤学   221篇
  2023年   18篇
  2022年   39篇
  2021年   121篇
  2020年   55篇
  2019年   50篇
  2018年   69篇
  2017年   46篇
  2016年   51篇
  2015年   72篇
  2014年   81篇
  2013年   94篇
  2012年   129篇
  2011年   161篇
  2010年   72篇
  2009年   78篇
  2008年   88篇
  2007年   105篇
  2006年   87篇
  2005年   101篇
  2004年   81篇
  2003年   72篇
  2002年   62篇
  2001年   53篇
  2000年   68篇
  1999年   44篇
  1998年   50篇
  1997年   62篇
  1996年   38篇
  1995年   34篇
  1994年   23篇
  1993年   16篇
  1992年   18篇
  1991年   36篇
  1990年   25篇
  1989年   36篇
  1988年   35篇
  1987年   30篇
  1986年   33篇
  1985年   35篇
  1984年   18篇
  1983年   17篇
  1982年   21篇
  1981年   10篇
  1980年   18篇
  1979年   10篇
  1978年   10篇
  1977年   12篇
  1976年   16篇
  1975年   4篇
  1973年   2篇
排序方式: 共有2508条查询结果,搜索用时 15 毫秒
31.
The HIV family replicate in and are shed from the mouth. Oral sexual practices potentially contribute to the overall extent of HIV transmission, particularly if high-risk practices are not restricted. Herpesviruses and papillomaviruses that appear in the oral cavity can determine oral HIV replication. The mechanisms probably include heterologous transactivation, enhanced expression of HIV receptors and co-receptors in target cells, release of cytokines and chemokines, and production of superantigens. Oral diseases peculiar to, or more common in, the HIV-infected patient further predispose to heightened oral HIV replication and trafficking. Defining the mechanisms by which oral viruses interact with HIV in the co-infected host should permit intervention measures against oral HIV transmission to be more precisely targeted.  相似文献   
32.
P H Held  K K Teo  S Yusuf 《Circulation》1990,82(5):1668-1674
An overview of eight randomized controlled trials of tissue-type plasminogen activator (Alteplase or Duteplase) and 10 of anisoylated plasminogen streptokinase activator complex (Anistreplase) showed that the odds of early death were reduced by 29% by tissue-type plasminogen activator and 46% by anisoylated plasminogen streptokinase activator complex, with overlapping 95% confidence intervals. Although the beneficial effects of both agents are consistent and are strengthened when all the trials are considered together, the available data do not permit comparisons of the relative efficacy of these two agents with each other or with streptokinase.  相似文献   
33.
34.
35.
We studied polymyxin B resistance in 10 pairs of clinical Acinetobacter baumannii isolates, two of which had developed polymyxin B resistance in vivo. All polymyxin B-resistant isolates had lower growth rates than and substitution mutations in the lpx or pmrB gene compared to their parent isolates. There were significant differences in terms of antibiotic susceptibility and genetic determinants of resistance in A. baumannii isolates that had developed polymyxin B resistance in vivo compared to isolates that had developed polymyxin B resistance in vitro.  相似文献   
36.
Patients presenting for emergency abdominal procedures often have medical issues that cause both general anaesthesia and central neuraxial blockade to pose significant risks. Regional anaesthetic techniques are often used adjunctively for abdominal procedures under general anaesthesia, but there is limited published data on procedures done under peripheral nerve or plexus blocks. We herein report the case of a patient with recent pulmonary embolism and supraventricular tachycardia who required colostomy refashioning. Ultrasonography-guided regional anaesthesia was administered using a combination of ilioinguinal-iliohypogastric, rectus sheath and transversus abdominis plane blocks. This was supplemented with propofol and dexmedetomidine sedation as well as intermittent fentanyl and ketamine boluses to cover for visceral stimulation. We discuss the anatomical rationale for the choice of blocks and compare the anaesthetic conduct with similar cases that were previously reported.  相似文献   
37.
Most cases of intussusception in adults present with chronic and nonspecifi c symptoms, and can sometimes be challenging to diagnose. We herein report on a patient w ith the rare symptom of colonic intussusceptions presenting with rectal prolapse and review the existing literature of similar case reports to discuss how to reach an accurate diagnosis. A 75-year-old woman with dementia presented with per rectal bleeding, rectal prolapse and lower abdominal pain. An operation was scheduled and a large sigmoid intussusception with a polyp as a leading point was found intraoperatively. She subsequently recovered well and was discharged. As large sigmoid intussusceptions may present as rectal prolapse, intussusception should be considered as a differential diagnosis for immobile patients, especially when the leading point is a lesion.  相似文献   
38.
BackgroundNo-shows are a persistent and costly problem in all healthcare systems. Because forgetting is a common cause of no-shows, appointment reminders are widely used. However, qualitative research examining appointment reminders and how to improve them is lacking.ObjectiveTo understand how patients experience appointment reminders as part of intervention development for a pragmatic trial of enhanced appointment reminders.DesignQualitative content analysisParticipantsTwenty-seven patients at a single Department of Veterans Affairs hospital and its satellite clinicsApproachWe conducted five waves of interviews using rapid qualitative analysis, in each wave continuing to ask veterans about their experience of reminders. We double-coded all interviews, used deductive and inductive content analysis to identify themes, and selected quotations that exemplified three themes (limitations, strategies, recommendations).Key ResultsInterviews showed four limitations on the usability of current appointment reminders which may contribute to no-shows: (1) excessive information within reminders; (2) frustrating telephone systems when calling in response to an appointment reminder; (3) missing or cryptic information about clinic logistics; and (4) reminder fatigue. Patients who were successful at keeping appointments often used specific strategies to optimize the usability of reminders, including (1) using a calendar; (2) heightening visibility; (3) piggybacking; and (4) combining strategies. Our recommendations to enhance reminders are as follows: (1) mix up their content and format; (2) keep them short and simple; (3) add a personal touch; (4) include specifics on clinic location and contact information; (5) time reminders based on the mode of delivery; and (6) hand over control of reminders to patients.ConclusionsAppointment reminders are vital to prevent no-shows, but their usability is not optimized for patients. There is potential for healthcare systems to modify several aspects of the content, timing, and delivery of appointment reminders to be more effective and patient-centered.Electronic supplementary materialThe online version of this article (10.1007/s11606-020-06183-5) contains supplementary material, which is available to authorized users.KEY WORDS: access to care, no-shows, missed appointments, reminder, military veterans  相似文献   
39.
AIM: To assess the efficacy of hemoclip application in combination with epinephrine injection in the treatment of bleeding peptic ulcers and to compare the clinical outcomes between patients treated with such a combination therapy and those treated with epinephrine injection alone. METHODS: A total of 293 patients (211 males, 82 females) underwent endoscopic therapy for bleeding peptic ulcers. Of these, 202 patients (152 males, 50 females) received epinephrine injection therapy while 91 patients (59 males, 32 females) received combination therapy. The choice of endoscopic therapy was made by the endoscopist. Hemostatic rates, rebleeding rates, need for emergency surgery and 30-d mortality were the outcome measures studied. RESULTS: Patients who received combination therapy were significantly older (mean age 66±16 years, range 24-90 years) and more suffered from chronic renal failure compared to those who received epinephrine injection therapy alone (mean age 61±17 years, range 21-89 years). Failure to achieve permanent hemostasis was 4% in the group who received epinephrine injection alone and 11% in the group who received combination therapy. When the differences in age and renal function between the two treatment groups were taken into account by multivariate analysis, the rates of initial hemostasis, rebleeding rates, need for surgery and 30-d mortality for both treatment options were not significantly different. CONCLUSION: Combination therapy of epinephrine injection with endoscopic hemoclip application is an effective method of achieving hemostasis in bleeding peptic ulcer diseases. However, superiority of combination therapy over epinephrine injection alone, could not be demonstrated.  相似文献   
40.
INTRODUCTIONDuring stress echocardiography, the echocardiologist routinely collects both echocardiographic images and stress electrocardiogram (ECG) concurrently. The managing physician faces a dilemma when the stress ECG and stress echocardiography results are discordant; for example, when a patient has negative stress echocardiography but positive stress ECG. We therefore sought to evaluate the prognostic value of stress echocardiography in relation to concordant or discordant stress ECG findings in our local Singapore setting, which has a well-defined Southeast Asian population.METHODSThis was a retrospective observational study of all patients who underwent stress echocardiography in 2012 at Changi General Hospital, Singapore. All study patients were followed up for 18 months via electronic medical records.RESULTSThere was no difference in the major adverse cardiovascular events (MACE) outcome of patients with normal stress echocardiography and normal stress ECG (reference group) as compared with patients with normal stress echocardiography but positive (discordant) stress ECG (odds ratio 2.02, 95% confidence interval 0.82‑4.98; p = 0.125).CONCLUSIONThis study will help to reassure cardiologists that discordant results (negative stress echocardiography but positive stress ECG) do not portend a higher risk of MACE when compared to concordant results (i.e. both stress echocardiography and stress ECG are negative).  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