全文获取类型
收费全文 | 2452篇 |
免费 | 161篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 83篇 |
妇产科学 | 61篇 |
基础医学 | 284篇 |
口腔科学 | 66篇 |
临床医学 | 278篇 |
内科学 | 449篇 |
皮肤病学 | 57篇 |
神经病学 | 204篇 |
特种医学 | 213篇 |
外国民族医学 | 1篇 |
外科学 | 298篇 |
综合类 | 66篇 |
一般理论 | 3篇 |
预防医学 | 250篇 |
眼科学 | 52篇 |
药学 | 150篇 |
中国医学 | 3篇 |
肿瘤学 | 88篇 |
出版年
2021年 | 20篇 |
2019年 | 22篇 |
2018年 | 35篇 |
2017年 | 27篇 |
2016年 | 27篇 |
2015年 | 47篇 |
2014年 | 50篇 |
2013年 | 64篇 |
2012年 | 76篇 |
2011年 | 87篇 |
2010年 | 52篇 |
2009年 | 92篇 |
2008年 | 96篇 |
2007年 | 103篇 |
2006年 | 85篇 |
2005年 | 81篇 |
2004年 | 91篇 |
2003年 | 65篇 |
2002年 | 66篇 |
2001年 | 59篇 |
2000年 | 59篇 |
1999年 | 62篇 |
1998年 | 74篇 |
1997年 | 73篇 |
1996年 | 74篇 |
1995年 | 53篇 |
1994年 | 56篇 |
1993年 | 51篇 |
1992年 | 50篇 |
1991年 | 49篇 |
1990年 | 53篇 |
1989年 | 44篇 |
1988年 | 53篇 |
1987年 | 67篇 |
1986年 | 60篇 |
1985年 | 42篇 |
1984年 | 32篇 |
1983年 | 27篇 |
1982年 | 43篇 |
1980年 | 17篇 |
1979年 | 31篇 |
1978年 | 26篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1974年 | 16篇 |
1970年 | 18篇 |
1969年 | 15篇 |
1968年 | 20篇 |
1967年 | 19篇 |
1966年 | 17篇 |
排序方式: 共有2624条查询结果,搜索用时 15 毫秒
31.
Lack of effect of combined low intensity laser therapy/phototherapy (CLILT) on delayed onset muscle soreness in humans 总被引:7,自引:0,他引:7
BACKGROUND AND OBJECTIVES: This study, which was approved by the University's Ethical committee, was conducted to investigate the effectiveness of Combined Low Intensity Laser Therapy/Phototherapy (CLILT) in alleviating the signs and symptoms of Delayed Onset Muscle Soreness (DOMS) over an 11-day period. STUDY DESIGN/MATERIALS AND METHODS: Thirty-six subjects (18 M: 18 F) were randomly allocated, under strictly controlled double-blind conditions, to one of three experimental conditions: Control, Placebo, and CLILT (660-950 nm; 11 J/cm2; pulsed at 73 Hz). DOMS was induced in a standardised fashion in the non-dominant elbow flexors using repeated eccentric contractions until exhaustion was reached. Subjects returned on five consecutive days, and two days during the following week, for treatment according to group, and assessment of outcome variables including range of motion, pain, and tenderness. RESULTS: While analysis of results using repeated measures and one factor ANOVA with post-hoc tests showed significant changes in all variables over time (P < 0.05) as a result of the induction procedure, there were no significant differences observed between groups. CONCLUSIONS: CLILT failed to show any beneficial treatment effect on DOMS, at least at the parameters used here. These results therefore provide no evidence for the claimed biostimulating effects of such therapy. 相似文献
32.
Zusammenassung In der vorliegenden Studie sollte untersucht werden, ob die vonPetrovic, Lavergne undStutzmann vorgeschlagene Kategorisierung des mandibulären Wachstumspotentials für die Behandlung mit dem Funktionsregler Geltung hat. Dazu wurden die Fernröntgenaufnahmen von 140 Patienten der Angle-Klasse II nach zirka zweijähriger Behandlung mit Funktionsreglern analysiert. Im Vergleich zu 133 unbehandelten Kindern mit Angle-Klasse II trat in fast allen Rotationsgruppen eine signifikant größere Zunahme der Unterkiefergesamtlänge ein. Zwischen der Kategorie 2 mit niedrigem Wachstumpotential und Kategorie 5 mit hohem Wachstumspotential wurden keine signifikant unterschiedlichen Zunahmen der Unterkieferlänge festgestellt.
Summary The results of the study show whether the classification of mandibular growth potential, as proposed by Petrovic, Lavergne and Stutzmann has any influence on the treatment with a function regulator. X-rays of 140 class II patients were analysed after a treatment time of approximately 2 years. In comparison with 133 class II children without any treatment, a significant increase of the overall mandibular length was observed in almost all children treated. There was no significant difference in the increase of mandibular length between category 2 (low growth potential) and category 5 (high growth potential).相似文献
33.
Barron E 《Same-day surgery》1982,6(10):117-120
34.
Prevalence, clinical characteristics, and mortality among patients with myocardial infarction presenting without chest pain 总被引:32,自引:2,他引:30
Canto JG Shlipak MG Rogers WJ Malmgren JA Frederick PD Lambrew CT Ornato JP Barron HV Kiefe CI 《JAMA》2000,283(24):3223-3229
CONTEXT: Although chest pain is widely considered a key symptom in the diagnosis of myocardial infarction (MI), not all patients with MI present with chest pain. The extent to which this phenomenon occurs is largely unknown. OBJECTIVES: To determine the frequency with which patients with MI present without chest pain and to examine their subsequent management and outcome. DESIGN: Prospective observational study. SETTING AND PATIENTS: A total of 434,877 patients with confirmed MI enrolled June 1994 to March 1998 in the National Registry of Myocardial Infarction 2, which includes 1674 hospitals in the United States. MAIN OUTCOME MEASURES: Prevalence of presentation without chest pain; clinical characteristics, treatment, and mortality among MI patients without chest pain vs those with chest pain. RESULTS: Of all patients diagnosed as having MI, 142,445 (33%) did not have chest pain on presentation to the hospital. This group of MI patients was, on average, 7 years older than those with chest pain (74.2 vs 66.9 years), with a higher proportion of women (49.0% vs 38.0%) and patients with diabetes mellitus (32.6% vs 25. 4%) or prior heart failure (26.4% vs 12.3%). Also, MI patients without chest pain had a longer delay before hospital presentation (mean, 7.9 vs 5.3 hours), were less likely to be diagnosed as having confirmed MI at the time of admission (22.2% vs 50.3%), and were less likely to receive thrombolysis or primary angioplasty (25.3% vs 74.0%), aspirin (60.4% vs 84.5%), beta-blockers (28.0% vs 48.0%), or heparin (53.4% vs 83.2%). Myocardial infarction patients without chest pain had a 23.3% in-hospital mortality rate compared with 9.3% among patients with chest pain (adjusted odds ratio for mortality, 2. 21 [95% confidence interval, 2.17-2.26]). CONCLUSIONS: Our results suggest that patients without chest pain on presentation represent a large segment of the MI population and are at increased risk for delays in seeking medical attention, less aggressive treatments, and in-hospital mortality. JAMA. 2000;283:3223-3229 相似文献
35.
Kangaroo Care with a ventilated preterm infant 总被引:4,自引:0,他引:4
36.
Yang PY Almofti MR Lu L Kang H Zhang J Li TJ Rui YC Sun LN Chen WS 《第二军医大学学报》2006,27(6):637-637
Polygonum multiflorum stilbeneglycoside (PMS) is a water-soluble fraction of Polygonum multiflorum Thunb. , one of the most famous tonic traditional Chinese medicines, that has protective effects on the cardiovascular system. The purpose of the present study is to elucidate the effects of PMS on macrophage-derived foam cell functions and the reduction of severity of atherosclerosis in hypercholesterolemic New Zealand White (NZW) rabbits. NZW rabbits were fed for 12 weeks with a normal diet, a high cholesterol diet, or a high cholesterol diet associated with irrigation with different doses of PMS (25, 50, or 100 mg/kg). Treatment of NZW rabbits fed with high cholesterol diet with 100 mg/kg PMS attenuated the increase in plasma cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and plasma triglyceride. Treatment with 50 and 100 mg/kg PMS caused 43% and 60% decrease in atherosclerotic lesioned area ratio to total surface area, respectively. In U937 foam cells, PMS could decrease the high expression of intercellular adhesion molecule (ICAM)-1 protein and the vascular endothelial growth factor (VEGF) protein levels in the medium induced by oxidized lipoprotein when analyzed by flow cytometry. The results proved that PMS is a powerful agent against atherosclerosis and that PMS action could possibly be through the inhibition of the expression of ICAM-1 and VEGF in foam cells. 相似文献
37.
Tiffany L. Sarrafian Jennifer L. Brazzell Matthew Barron Johnathon Aho Ellen Blanco Chelsea Powell Jed Johnson Dennis A. Wigle 《Journal of thoracic disease》2022,14(6):1830
BackgroundMany esophageal pathologies are clinically treated by resection and reconstruction of the esophagus. Surgical esophagectomy remains a morbid procedure and despite minimally invasive advances, has changed little in decades. Novel approaches to esophageal segmental resection and reconstruction are an unmet need.MethodsCircumferential thoracic esophageal transection was performed in both male and female pigs and the defects reconstructed using 5 or 10 cm polyurethane (PU) tubular grafts and stented. A subset were treated with stent only. Animals were survived to 14, 30, 60, and 399 days. Tissues were evaluated histologically, and via non-invasive serial endoscopy and contrast swallowing studies in long-term animals.ResultsLuminal patency was achieved in all animals with no clinical evidence of leak. In short-term animals, there was healing noted in all cases with a variably sized region of ulceration remaining at the most central part of the repaired tube (between the proximal and distal anastomosis). In four long-term animals following stent removal, two resumed normal diet and thrived, while two animals were euthanized prior to the proposed endpoint because of stricture formation and inability to tolerate a normal diet. Re-epithelialization was observed in all groups, and more complete over time.ConclusionsThe PU scaffold provides a matrix across which formation of new tissue can occur. The mechanisms through which this happens remain unclear, but likely a combination of fibrosis and tissue contraction, in conjunction with new tissue formation. 相似文献
38.
The dose-response ototoxic effects of cisplatin were studied in guinea pigs. Loss of Preyer reflex and suppression of the N1 amplitude occurred in cisplatin-treated animals and was described as dose-related. Drug-induced hair cell damage, as observed with scanning electron microscopy, occurred sporadically throughout the turns of the cochlea and the incidence increased with dose. Na,K-ATPase activity in the lateral wall tissues was not significantly different between treatment groups. The results reported here indicate that cisplatin ototoxicity was dose-dependent, but was not directly related to Na,K-ATPase activity in the lateral wall. 相似文献
39.
We studied the effect of vagal afferents on the left ventricular contractile response (LVdP/dtmax) to administration of sympathomimetic amines into the left circumflex coronary artery in conscious dogs. The positive inotropic effects of bolus administration of epinephrine, norepinephrine, and isoproterenol were greater during bilateral vagal cold block (BVB) that in the control state with the vagi intact (P less than 0.001). The inotropic potentiation observed with BVB was not due to vagal efferent interruption, since parasympathetic efferent block with atropine did not potentiate the inotropic effects of intracoronary epinephrine (P greater than 0.05). BVB also potentiated the inotropic effects of constant intracoronary infusion of epinephrine (P less than 0.01). BVB alone had no significant effect on LVdP/dtmax; dtmax (P less than 0.05). We propose that the potentiation of the inotropic effects during BVB could result from either interruption of a vagal afferent-mediated negative feedback reflex and/or an unmasking of a sympathetic afferent-mediated positive feedback effect induced by BVB. However, the observations that ganglionic blockade also potentiated the contractile effects of epinephrine supports the concept that a negative feedback reflex does attenuate the inotropic effect of catecholamines in the control state. In conclusion, these data suggest that vagal afferents attenuate the positive inotropic effects of intracoronary administration of catecholamines via a cardiocardiac negative feedback reflex which occurs through a vagal afferent inhibition of sympathetic efferent activity back to the left ventricle. 相似文献
40.
前胡丙素与硝苯啶对大鼠工作心脏缺血再灌注损伤的保护作用 总被引:4,自引:3,他引:4
大鼠ip前胡丙素(Pra-C 15 mg/kg,bid×3d)和硝苯啶(Nif 60μg/kg,bid×3d),使离体缺血再灌注工作心脏的收缩(AP,LVSP,+dP/dtmax)舒张(-dP/dtmax LVEDP和T值)性能在35min时得到改善,尤以舒张性能改善明显,并能促进CO,CF,SV及HR恢复,改善心脏工作效率,减少CK释放和心肌线粒体钙含量,表明Pra-C和Nif对心肌缺血都有保护作用,Pra-C的效应与Nif相近。 相似文献