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   1147332篇
  免费   82770篇
  国内免费   2927篇
耳鼻咽喉   15106篇
儿科学   38792篇
妇产科学   32133篇
基础医学   166897篇
口腔科学   32658篇
临床医学   98969篇
内科学   227463篇
皮肤病学   27052篇
神经病学   91182篇
特种医学   41986篇
外国民族医学   305篇
外科学   167065篇
综合类   24455篇
一般理论   409篇
预防医学   95893篇
眼科学   26574篇
药学   83587篇
  3篇
中国医学   2635篇
肿瘤学   59865篇
  2021年   9116篇
  2019年   9903篇
  2018年   15108篇
  2017年   11037篇
  2016年   12148篇
  2015年   13719篇
  2014年   17814篇
  2013年   27231篇
  2012年   38413篇
  2011年   40852篇
  2010年   23342篇
  2009年   20935篇
  2008年   37012篇
  2007年   39325篇
  2006年   39527篇
  2005年   37812篇
  2004年   36612篇
  2003年   35033篇
  2002年   33654篇
  2001年   51380篇
  2000年   53117篇
  1999年   44095篇
  1998年   11819篇
  1997年   10482篇
  1996年   10543篇
  1995年   10119篇
  1994年   9383篇
  1992年   34184篇
  1991年   33218篇
  1990年   32741篇
  1989年   31358篇
  1988年   28605篇
  1987年   28649篇
  1986年   26818篇
  1985年   25888篇
  1984年   19310篇
  1983年   16309篇
  1982年   9681篇
  1979年   17934篇
  1978年   12910篇
  1977年   10988篇
  1976年   10391篇
  1975年   10943篇
  1974年   13321篇
  1973年   12888篇
  1972年   11875篇
  1971年   11077篇
  1970年   10265篇
  1969年   9681篇
  1968年   9073篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
22.
23.
Introduction: The treatment of classical Hodgkin lymphoma (cHL) in children is a story of success. Nowadays, more than 90% of patients are cured and overall survival is nearly 100% at 5 years. Efforts have been made to avoid related effects of therapies; therefore, children are treated using different chemotherapy schemes in comparison with adults.

Areas covered: This review includes a view of the clinical classification and risk assessment in children suffering from HL. The chemotherapy more commonly employed is revisited. The use of PET/CT to evaluate the disease in order to guide therapy is analyzed. New options of chemotherapy and emerging immunotherapy are also included.

Expert opinion: In order to make the right treatment choice, a proper initial assessment of risk is mandatory. The choice of therapy in these kinds of patients must be done according to the experience of the team, and also, the cost and logistics related to the eligible scheme are very important. If possible, efforts must be made to include PET/CT in guiding therapy and avoiding overtreatment and long-term adverse effects in children. New options in immunotherapy are emerging and must be considered with caution in selected patients.  相似文献   

24.

Purpose

Endovascular treatment with mechanical thrombectomy devices demonstrated high recanalization rates but functional outcome did not correlate with high rates of recanalization obtained. Patient selection prior to the endovascular treatment is very important in the final outcome of the patient. The primary aim of our study was to evaluate the prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and Pons-Midbrain Index (PMI) scores in patients with Basilar Artery Occlusion (BAO) treated with successful angiographic recanalization after mechanical thrombectomy.

Methods

Retrospective single-center study including 18 patients between 2008 and 2013 who had acute basilar artery occlusion managed with endovascular treatment within 24 hours from symptoms onset and with successful angiographic recanalization. The patients were initially classified into two groups according to clinical outcome and mortality at 90 days. For analysis we also divided patients into groups based on pc-ASPECTS (≥8vs.< 8) and PMI (≥3vs.< 3) on non-contrast CT (NCCT) and CT Angiography Source Images (CTASI). Imaging data were correlated to clinical outcome and mortality rate.

Results

CTASI pc-ASPECTS, dichotomized at < 8 versus≥8, was associated with a favorable outcome (RR: 2.6; 95% CI: 1.3-5.2) and a reduced risk of death (RR: 6.5: 95% CI: 7.8-23.3). All patients that survived and were functionally independent had pc-ASPECTS score≥8. None of the 5 patients with CTASI pc-ASPECTS score less than 8 survived.

Conclusion

PC-ASPECTS on CTASI is helpful for predicting functional outcome after BAO recanalization with endovascular treatment. These results should be validated in a randomized controlled trial in order to decide whether or not to treat a patient with BAO.  相似文献   
25.
26.
27.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
28.
29.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
30.
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