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   46937篇
  免费   4173篇
  国内免费   82篇
耳鼻咽喉   441篇
儿科学   1570篇
妇产科学   1356篇
基础医学   6225篇
口腔科学   837篇
临床医学   5781篇
内科学   8919篇
皮肤病学   859篇
神经病学   4615篇
特种医学   1205篇
外科学   5492篇
综合类   817篇
一般理论   51篇
预防医学   5755篇
眼科学   751篇
药学   3580篇
  1篇
中国医学   50篇
肿瘤学   2887篇
  2023年   395篇
  2022年   498篇
  2021年   1136篇
  2020年   682篇
  2019年   1150篇
  2018年   1229篇
  2017年   938篇
  2016年   952篇
  2015年   1043篇
  2014年   1441篇
  2013年   2098篇
  2012年   3146篇
  2011年   3306篇
  2010年   1767篇
  2009年   1543篇
  2008年   2556篇
  2007年   2837篇
  2006年   2581篇
  2005年   2437篇
  2004年   2150篇
  2003年   2084篇
  2002年   1859篇
  2001年   798篇
  2000年   747篇
  1999年   677篇
  1998年   429篇
  1997年   310篇
  1996年   279篇
  1995年   324篇
  1994年   279篇
  1993年   235篇
  1992年   549篇
  1991年   505篇
  1990年   483篇
  1989年   472篇
  1988年   439篇
  1987年   442篇
  1986年   395篇
  1985年   452篇
  1984年   391篇
  1983年   310篇
  1982年   302篇
  1981年   245篇
  1980年   247篇
  1979年   355篇
  1978年   297篇
  1976年   245篇
  1974年   280篇
  1973年   290篇
  1972年   233篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed. We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004–2005 School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic (EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels, with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10) and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities in Spanish-speaking Hispanic children’s PA participation.  相似文献   
42.
43.
44.
Popliteal artery aneurysms representing 80% of peripheral artery aneurysms rarely rupture (a reported incidence of 0.1–2.8 %) and second commonest in frequency after aorto-iliac aneurysms. They usually present with pain, swelling, occlusion or distal embolisation and can cause diagnostic difficulties. We report a 78 year old man who was previously admitted to hospital with a pulmonary embolus secondary to deep venous thrombosis. He was heparinized then warfarinised and was readmitted with a ruptured popliteal aneurysm leading to a large pseudo aneurysm formation. The pulmonary embolus had been due to popliteal vein thrombosis and propagation of the clot. A thorough review of literature identified only one previously reported case of ruptured popliteal artery aneurysm and subsequent large pseudo aneurysm formation. We feel it is important to exclude a popliteal aneurysm in a patient with DVT. This may be more common than the published literature suggests.  相似文献   
45.
46.
OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation.  相似文献   
47.
48.
Infections are the most common complication in patients receiving treatment for cancer with neutropenia being the primary risk factor for the development of an infection. In the neutropenic patient, bacteremia remains a significant cause of mortality. Although the literature reports that prompt empiric antibiotic therapy to prevent death caused by virulent organisms is the standard of care, the literature fails to identify what prompt antibiotic administration means. Door/fever-to-patient antibiotic delivery was evaluated as a quality control measure in a new children's hospital. Initially, door/fever-to-patient time was significantly delayed. Collaboration between pharmacy, hospital bed control, medical, and nursing staff resulted in many changes in practice by all groups. As a result, the goal for prompt antibiotic delivery of thirty minutes or less is now achievable.  相似文献   
49.
INTRODUCTION: Limited access to medical care has resulted in large numbers of patients seeking primary care for non-emergent emergency conditions in emergency departments. This influx of patients is contributing to overcrowding and delays in care for patients with emergencies. In response, a system was implemented in which persons with non-emergent medical conditions, following a medical screening examination, did not receive further ED assessment or treatment and instead were referred to community resources. The purpose of this study was to describe the characteristics of individuals who were referred to community-based services, their condition after 72 hours, and their use of follow-up health care services. METHODS: All referred cases (n=225) were reviewed for chief complaint and demographics. Phone contact was attempted after 72 hours to determine the person's condition and if community resources were utilized. RESULTS: Of the 225 cases, 52% were female, with a mean age of 33 years. Their most common chief complaints were extremity problems (16%), toothache (9%), and medication refill (8%). Follow-up phone contact was successful with 82 people (37%) an average of 14 days after their ED visit. The majority (55%) reported their condition had improved; 39%were unchanged, and 6% were worse. Thirty-one people(40%) accessed community resources and 8 (26%) returned to another emergency department. No clinically significant associations were found between patient demographics and use of community resources. DISCUSSION: Most people who were successfully contacted for follow-up and who had come to the emergency department with non-emergent chief complaints did not access community resources and their condition frequently improved. Additional studies, with improved follow-up, are needed before suggesting that referring individuals to community resources is an acceptable practice.  相似文献   
50.
A technique for arthrodesis of small joints of the hand is described that uses a tenon to secure apposition that has good intrinsic stability as well as a large surface area of cancellous bony contact. A minimum of postoperative immobilization is required. The tenon arthrodesis method has been employed in 85 joints. The literature shows pseudoarthrosis rates of 0 to 33%. This technique had a 2.3% failure rate that compares favorably with those in other published series.  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