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   4657521篇
  免费   372319篇
  国内免费   30424篇
耳鼻咽喉   63579篇
儿科学   142509篇
妇产科学   121942篇
基础医学   699497篇
口腔科学   129359篇
临床医学   430946篇
内科学   835962篇
皮肤病学   113744篇
神经病学   381416篇
特种医学   182326篇
外国民族医学   812篇
外科学   702274篇
综合类   165329篇
现状与发展   79篇
一般理论   2602篇
预防医学   371766篇
眼科学   112763篇
药学   337061篇
  216篇
中国医学   24918篇
肿瘤学   241164篇
  2021年   66474篇
  2020年   43627篇
  2019年   65603篇
  2018年   81246篇
  2017年   62745篇
  2016年   68557篇
  2015年   84804篇
  2014年   121284篇
  2013年   184958篇
  2012年   136633篇
  2011年   143027篇
  2010年   134948篇
  2009年   134252篇
  2008年   123061篇
  2007年   130941篇
  2006年   138938篇
  2005年   133974篇
  2004年   131144篇
  2003年   120600篇
  2002年   109267篇
  2001年   173806篇
  2000年   169574篇
  1999年   155641篇
  1998年   74877篇
  1997年   70499篇
  1996年   67748篇
  1995年   63016篇
  1994年   56765篇
  1993年   52353篇
  1992年   111256篇
  1991年   106730篇
  1990年   102176篇
  1989年   99789篇
  1988年   92161篇
  1987年   90049篇
  1986年   85681篇
  1985年   83556篇
  1984年   69480篇
  1983年   61496篇
  1982年   48701篇
  1981年   45270篇
  1980年   42569篇
  1979年   60468篇
  1978年   48399篇
  1977年   43369篇
  1976年   39647篇
  1975年   40444篇
  1974年   44843篇
  1973年   43180篇
  1972年   40722篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
One unreported case of extended-spectrum-beta-lactamase (ESBL)-producing Salmonella enterica serovar Typhi was identified, whole-genome sequence typed, among other analyses, and compared to other available genomes of S. Typhi. The reported strain was similar to a previously published strain harboring blaSHV-12 from the Philippines and likely part of an undetected outbreak, the first of ESBL-producing S. Typhi.  相似文献   
944.
IntroductionPain is highly prevalent in patients with multiple sclerosis (MS); it is chronic in 50% of cases and is classified as nociceptive, neuropathic, or mixed-type. Pain affects quality of life, sleep, and the activities of daily living. Electrotherapy is an interesting alternative or complementary treatment in the management of pain in MS, with new innovations constantly appearing.Material and methodsThis study evaluates the effectiveness of treatment with monopolar dielectric transmission of pulsed electromagnetic fields (PEMF) for pain associated with MS. We performed a randomised, placebo-controlled clinical trial including 24 patients, who were assessed with the Brief Pain Inventory, the Multiple Sclerosis International Quality of Life questionnaire, the Beck Depression Inventory, and the Modified Fatigue Impact Scale.ResultsStatistically significant improvements were observed in maximum and mean pain scores, as well as in the impact of pain on work, personal relationships, and sleep and rest. Not significant differences were found between the treatment and placebo groups.ConclusionsTreatment with PEMF may be effective in reducing pain in patients with MS, although further research is necessary to confirm its effectiveness over placebo and to differentiate which type of pain may be more susceptible to this treatment.  相似文献   
945.
PurposeTwitter is an increasingly popular social media platform within the health care community. The objective of this analysis is to characterize the profile of radiation oncology–related tweets and Twitter users over the past 6 years.Methods and MaterialsUsing the web-based social media analytics platform Symplur Signals, we filtered tweets containing at least 1 of the following hashtags or key words: #radonc, #radiationoncology, "rad onc," or "radiation oncology." We evaluated radiation oncology–related Twitter activity between October 2014 and March 2020 for tweet frequency, tweet content, and individuals or groups posting tweets. We identified the most influential Twitter users contributing to radiation oncology–related tweets.ResultsFrom 2014 to 2020, the quarterly volume of radiation oncology–related tweets increased from 5027 to 29,763. Physicians contributed the largest growth in tweet volume. Academic radiation oncologists comprise 60% of the most influential Twitter accounts responsible for radiation oncology–related content. The number of radiation-oncology resident physicians on Twitter increased from 25 to 328 over the past 6 years, and 20% of radiation-oncology residency programs have a Twitter account. Seventy-one percent of radiation oncology–related tweets generated direct communication via mentions, and 59% of tweets contain links to external sources, including scientific articles.ConclusionsThe number of physicians contributing radiation oncology–related Twitter content has increased significantly in recent years. Academic radiation oncologists are the primary influencers of radiation oncology–related Twitter activity. Twitter is used by radiation oncologists to both professionally network and discuss findings related to the field. There remains the opportunity for radiation oncologists to broaden their audience on Twitter to encompass a more diverse community, including patients.  相似文献   
946.
BackgroundVenoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used as a life-saving therapy for patients with cardiovascular collapse, but identifying patients unlikely to benefit remains a challenge.Methods and ResultsWe created the RESCUE registry, a retrospective, observational registry of adult patients treated with VA-ECMO between January 2007 and June 2017 at 3 high-volume centers (Columbia University, Duke University, and Washington University) to describe short-term patient outcomes. In 723 patients treated with VA-ECMO, the most common indications for deployment were postcardiotomy shock (31%), cardiomyopathy (including acute heart failure) (26%), and myocardial infarction (17%). Patients frequently suffered in-hospital complications, including acute renal dysfunction (45%), major bleeding (41%), and infection (33%). Only 40% of patients (n = 290) survived to discharge, with a minority receiving durable cardiac support (left ventricular assist device [n = 48] or heart transplantation [n = 7]). Multivariable regression analysis identified risk factors for mortality on ECMO as older age (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.12–1.42) and female sex (OR, 1.44; 95% CI, 1.02–2.02) and risk factors for mortality after decannulation as higher body mass index (OR 1.17; 95% CI, 1.01-1.35) and major bleeding while on ECMO support (OR, 1.92; 95% CI, 1.23–2.99).ConclusionsDespite contemporary care at high-volume centers, patients treated with VA-ECMO continue to have significant in-hospital morbidity and mortality. The optimization of outcomes will require refinements in patient selection and improvement of care delivery.  相似文献   
947.
948.
The jobs of Latino manual laborers place their mental and physical health at risk. This study evaluates the associations among musculoskeletal pain, mental health, and work organization in Latino manual laborers. Farmworkers and nonfarmworkers (n = 189) in North Carolina were interviewed for self-reported musculoskeletal pain, depressive symptoms, stress, work safety climate, and precarious job status. More nonfarmworkers than farmworkers had neck and shoulder pain, but they did not differ in other areas of musculoskeletal pain. Depressive symptoms had a significant association with neck and shoulder pain (p < .05). Precariousness had a significant association with back pain (p < .05). Farmworker participants had H-2A visas and were afforded some protection compared to nonfarmworker manual workers. Research is needed to improve policy that relieves pain and improves mental health for all Latino manual workers.  相似文献   
949.
950.
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