全文获取类型
收费全文 | 16726篇 |
免费 | 1371篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 147篇 |
儿科学 | 543篇 |
妇产科学 | 322篇 |
基础医学 | 2340篇 |
口腔科学 | 271篇 |
临床医学 | 1627篇 |
内科学 | 3651篇 |
皮肤病学 | 175篇 |
神经病学 | 1353篇 |
特种医学 | 665篇 |
外科学 | 2832篇 |
综合类 | 271篇 |
一般理论 | 20篇 |
预防医学 | 1458篇 |
眼科学 | 402篇 |
药学 | 1026篇 |
1篇 | |
中国医学 | 14篇 |
肿瘤学 | 1023篇 |
出版年
2023年 | 81篇 |
2022年 | 135篇 |
2021年 | 316篇 |
2020年 | 211篇 |
2019年 | 321篇 |
2018年 | 432篇 |
2017年 | 289篇 |
2016年 | 304篇 |
2015年 | 349篇 |
2014年 | 516篇 |
2013年 | 692篇 |
2012年 | 1184篇 |
2011年 | 1151篇 |
2010年 | 649篇 |
2009年 | 570篇 |
2008年 | 1005篇 |
2007年 | 1072篇 |
2006年 | 1073篇 |
2005年 | 1024篇 |
2004年 | 1004篇 |
2003年 | 939篇 |
2002年 | 895篇 |
2001年 | 194篇 |
2000年 | 192篇 |
1999年 | 194篇 |
1998年 | 189篇 |
1997年 | 188篇 |
1996年 | 162篇 |
1995年 | 128篇 |
1994年 | 127篇 |
1993年 | 137篇 |
1992年 | 109篇 |
1991年 | 141篇 |
1990年 | 90篇 |
1989年 | 109篇 |
1988年 | 107篇 |
1987年 | 98篇 |
1986年 | 118篇 |
1985年 | 87篇 |
1984年 | 99篇 |
1983年 | 112篇 |
1982年 | 104篇 |
1981年 | 107篇 |
1980年 | 95篇 |
1979年 | 114篇 |
1978年 | 90篇 |
1977年 | 69篇 |
1976年 | 60篇 |
1975年 | 78篇 |
1974年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Wilson JS Fitzsimons D Bradbury I Stuart Elborn J 《International journal of nursing studies》2008,45(4):508-517
BACKGROUND: Smoking cessation is the primary disease modifying intervention for chronic obstructive pulmonary disease (COPD). SETTING: A Regional Respiratory Centre (RRC) out-patient department in Northern Ireland. METHODS: A randomised controlled trial (RCT) evaluated the effectiveness of brief advice alone or accompanied by individual nurse support or group support facilitated by nurses. Smoking status was biochemically validated and stage of change, nicotine addiction and dyspnoea were recorded at 2, 3, 6, 9 and 12 months. PARTICIPANTS: Ninety-one cigarette smokers with COPD were enrolled in the study (mean age 61 years, 47 female). RESULTS: After 12 months cessation rates were not significantly different between groups (p=0.7), but all groups had a significant reduction in their nicotine addiction (p=0.03-0.006). No changes in subjects' motivation or dyspnoea were detected over the 12 months. CONCLUSION: Patients with COPD were unable to stop smoking regardless of the type of support they received. Harm reduction may be a more appropriate goal than complete cessation for intractable smokers and nurses must evaluate their role in this arena. 相似文献
32.
Tansey MJ Tsalikian E Beck RW Mauras N Buckingham BA Weinzimer SA Janz KF Kollman C Xing D Ruedy KJ Steffes MW Borland TM Singh RJ Tamborlane WV;Diabetes Research in Children Network 《Diabetes care》2006,29(1):20-25
OBJECTIVE: To examine the acute glucose-lowering effects of aerobic exercise in children and adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Fifty children and adolescents with type 1 diabetes (ages 10 to <18 years) were studied during exercise. The 75-min exercise session consisted of four 15-min periods of walking on a treadmill to a target heart rate of 140 bpm and three 5-min rest periods. Blood glucose and plasma glucagon, cortisol, growth hormone, and norepinephrine concentrations were measured before, during, and after exercise. RESULTS: In most subjects (83%), plasma glucose concentration dropped at least 25% from baseline, and 15 (30%) subjects became hypoglycemic (< or = 60 mg/dl) or were treated for low glucose either during or immediately following the exercise session. The incidence of hypoglycemia and/or treatment for low glucose varied significantly by baseline glucose, occurring in 86 vs. 13 vs. 6% of subjects with baseline values <120, 120-180, and >180 mg/dl, respectively (P < 0.001). Exercise-induced increases in growth hormone and norepinephrine concentrations were marginally higher in subjects whose glucose dropped < or = 70 mg/dl. Treatment of hypoglycemia with 15 g of oral glucose resulted in only about a 20-mg/dl rise in glucose concentrations. CONCLUSIONS: In youth with type 1 diabetes, prolonged moderate aerobic exercise results in a consistent reduction in plasma glucose and the frequent occurrence of hypoglycemia when preexercise glucose concentrations are <120 mg/dl. Moreover, treatment with 15 g of oral glucose is often insufficient to reliably treat hypoglycemia during exercise in these youngsters. 相似文献
33.
34.
Benjamin Thurston Guilherme N. Pena Stuart Howell Prue Cowled Robert Fitridge 《Journal of vascular surgery》2018,67(2):460-467
Objective
Preoperative sarcopenia is an established risk factor for poor outcomes after surgery. Methods for assessing sarcopenia are either complex, time consuming, or poorly validated. We aimed to assess the interobserver reliability of scoring psoas area at the level of the L3 vertebra and to evaluate whether sarcopenia scored by this simple and rapid method correlated with other fitness scoring methods or impacted on mortality and duration of stay for patients undergoing endovascular aneurysm repair (EVAR).Methods
We had access to 191 preoperative computed tomography scans of patients who underwent EVAR. For each scan the axial slice at the most caudal level of the L3 vertebra was extracted. Three observers independently calculated the combined cross-sectional area of the left and right psoas muscle at this level. Interobserver variability was calculated as per Band and Altman. Psoas area was normalized for patient height with sarcopenia defined as total psoas area of <500 mm2/m2. The effect of sarcopenia on patient survival was assessed using Cox proportional hazards models. Kaplan-Meier curves are also presented.Results
Interobserver reliability of scoring psoas area was acceptable (reproducibility coefficient as percent of mean for each observer pair: 7.92%, 7.95%, and 14.33%). Sarcopenic patients had poorer survival (hazard ratio, 2.37; P = .011) and an increased hospital duration of stay (4.0 days vs 3.0 days; P = .008) when compared with nonsarcopenic patients. Sarcopenic patients were more likely to self-report as unfit (12.4% vs 33.3%; P = .004). Sarcopenia did not correlate with an increased rate of postprocedure complications.Conclusions
Psoas area scoring has good interobserver reliability. Preoperative sarcopenia as defined by psoas area was associated with poorer survival and of longer length of stay. As all patients being worked up for an endovascular aortic aneurysm repair will undergo a computed tomography scan, this method is a rapid and effective way to highlight patients in the clinic setting who have an increased risk of morbidity and mortality after EVAR. 相似文献35.
36.
37.
The mouth,stomach and intestines 总被引:1,自引:0,他引:1
Food is chewed into digestible portions in the mouth and swallowed – a complex reflex process involving several cranial nerves. The stomach homogenizes food, begins digestion and regulates the rate at which food enters the duodenum. Pancreatic juices containing powerful digesting enzymes are added and digestion is completed in the small intestine. The large bowel dehydrates the gastrointestinal contents. 相似文献
38.
Timothy J. Kidd Rafael Canton Miquel Ekkelenkamp Helle Krogh Johansen Peter Gilligan John J. LiPuma Scott C. Bell J. Stuart Elborn Patrick A. Flume Donald R. VanDevanter Valerie J. Waters 《Journal of cystic fibrosis》2018,17(6):696-704
Antimicrobial resistance (AMR) can present significant challenges in the treatment of cystic fibrosis (CF) lung infections. In CF and other chronic diseases, AMR has a different profile and clinical consequences compared to acute infections and this requires different diagnostic and treatment approaches. This review defines AMR, explains how it occurs, describes the methods used to measure AMR as well as their limitations, and concludes with future directions for research and development in the area of AMR in CF. 相似文献
39.
Beneficial effect of recombinant rC1rC2 collagenases on human islet function: Efficacy of low‐dose enzymes on pancreas digestion and yield 下载免费PDF全文
Gopalakrishnan Loganathan Venugopal Subhashree Andrew G. Breite William W. Tucker Siddharth Narayanan Maheswaran Dhanasekaran SriPrakash Mokshagundam Michael L. Green Michael G. Hughes Stuart K. Williams Francis E. Dwulet Robert C. McCarthy Appakalai N. Balamurugan 《American journal of transplantation》2018,18(2):478-485
A high number of human islets can be isolated by using modern purified tissue dissociation enzymes; however, this requires the use of >20 Wunsch units (WU)/g of pancreas for digestion. Attempts to reduce this dose have resulted in pancreas underdigestion and poor islet recovery but improved islet function. In this study, we achieved a high number of functional islets using a low dose of recombinant collagenase enzyme mixture (RCEM‐1200 WU rC2 and 10 million collagen‐degrading activity [CDA] U of rC1 containing about 209 mg of collagenase to digest a 100‐g pancreas). The collagenase dose used in these isolations is about 42% of the natural collagenase enzyme mixture (NCEM) dose commonly used to digest a 100‐g pancreas. Low‐dose RCEM was efficient in digesting entire pancreases to obtain higher yield (5535 ± 830 and 2582 ± 925 islet equivalent/g, P < .05) and less undigested tissue (16.7 ± 5% and 37.8 ± 3%, P < .05) compared with low‐dose NCEM (12WU/g). Additionally, low‐dose RCEM islets retained better morphology (confirmed with scanning electron microscopy) and higher in vitro basal insulin release (2391 ± 1342 and 1778 ± 978 μU/mL; P < .05) compared with standard‐dose NCEM. Nude mouse bioassay demonstrated better islet function for low‐dose RCEM (area under the curve [AUC] 24 968) compared with low‐dose (AUC–38 225) or standard‐dose NCEM (AUC–38 685), P < .05. This is the first report indicating that islet function can be improved by using low‐dose rC1rC2 (RCEM). 相似文献
40.