全文获取类型
收费全文 | 3260篇 |
免费 | 191篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 80篇 |
妇产科学 | 47篇 |
基础医学 | 473篇 |
口腔科学 | 106篇 |
临床医学 | 411篇 |
内科学 | 734篇 |
皮肤病学 | 74篇 |
神经病学 | 366篇 |
特种医学 | 124篇 |
外科学 | 354篇 |
综合类 | 10篇 |
一般理论 | 3篇 |
预防医学 | 254篇 |
眼科学 | 31篇 |
药学 | 209篇 |
中国医学 | 1篇 |
肿瘤学 | 170篇 |
出版年
2023年 | 17篇 |
2022年 | 24篇 |
2021年 | 57篇 |
2020年 | 45篇 |
2019年 | 54篇 |
2018年 | 50篇 |
2017年 | 56篇 |
2016年 | 88篇 |
2015年 | 65篇 |
2014年 | 97篇 |
2013年 | 193篇 |
2012年 | 209篇 |
2011年 | 198篇 |
2010年 | 131篇 |
2009年 | 154篇 |
2008年 | 199篇 |
2007年 | 193篇 |
2006年 | 182篇 |
2005年 | 215篇 |
2004年 | 185篇 |
2003年 | 171篇 |
2002年 | 172篇 |
2001年 | 72篇 |
2000年 | 43篇 |
1999年 | 51篇 |
1998年 | 32篇 |
1997年 | 32篇 |
1996年 | 26篇 |
1995年 | 31篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 35篇 |
1991年 | 19篇 |
1990年 | 18篇 |
1989年 | 14篇 |
1988年 | 22篇 |
1987年 | 20篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1976年 | 11篇 |
1975年 | 12篇 |
1970年 | 16篇 |
1969年 | 10篇 |
1966年 | 10篇 |
排序方式: 共有3457条查询结果,搜索用时 78 毫秒
1.
Hannah Lilly Mackenzie Bitzel Tatiana Pejnovic Joanna Schnell 《Physical Therapy Reviews》2019,24(5):195-207
AbstractBackground: Cerebral palsy (CP) is a common childhood disability. However, these individuals are now living longer lives, participating in adult roles, and seeking healthcare services. The transition from pediatric to adult healthcare for adolescents with CP is a challenging yet significant time. Adolescents experience several barriers during transition.Objectives: To utilize the environmental and personal dimensions of the ICF model in order to explore barriers when transitioning to adulthood as well as discuss characteristics and physical therapy implications needed to succeed within transition.Methods: Electronic searching of PubMed, CINAHL, ERIC, Scopus, ProQuest, and the Cochrane Library databases was concluded on January 9, 2019 for studies including transition between pediatric and adult healthcare in individuals diagnosed with CP. Two independent reviewers agreed upon inclusion, eligibility, and quality assessment of each study using the Mixed-Methods Appraisal Tool (MMAT).Results: Seven studies were included in the systematic review. Results for each study were separated based on the personal and environmental contextual factors of the ICF model and solutions to the barriers were then discussed.Conclusions: Research has provided proposed solutions to select barriers, however, other barriers have yet to be addressed. More research is needed to address these barriers and provide a model program that can be implemented within the healthcare systems to promote a successful transition for adolescents with CP from pediatric to adult services. 相似文献
2.
Knut E Kj?rstad Dag Ole Nordhaug Christian Korvald Stig Müller Tor Steensrud Truls Myrmel 《European journal of cardio-thoracic surgery》2007,31(4):677-684
OBJECTIVE: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload. METHODS: Left ventricular pressure-volume loops were assessed at baseline in eight open chest pigs using the combined pressure-volume conductance catheter technique during right atrial pacing at 120b/min. Mechanical restitution curves (MRC) were constructed during four different loading conditions in all eight animals: uninfluenced load, reduced preload (balloon catheter in v. cava inferior), increased afterload (balloon catheter in descending aorta), and increased preload combined with reduced afterload (aortocaval shunting). Acute LV failure was then induced by microembolization through the left main coronary artery, and the experimental protocol was repeated. Contractile response was defined as the maximal first derivative of pressure (dP/dt(max)), and T((MRC)) was calculated using a least square approximation algorithm. RESULTS: Hemodynamic data 30min after microembolization showed decreased mean arterial pressure (98+/-14-67+/-10mmHg, (mean+/-SD) P<0.0001) and dP/dt(max) (1482+/-193-1001+/-125mmHg/s, P=0.001). Stroke volume decreased from 30+/-5 to 20+/-5ml (P<0.0001) compared to baseline, and preload recruitable stroke work decreased from 52+/-7 to 31+/-10mmHg (P=0.002). T((MRC)) increased in all eight animals after induction of LV failure at all loading conditions. There was no difference between the different loading conditions at baseline, nor at LV heart failure, but T((MRC)) increased significantly after the induction of heart failure (ANOVA, two ways). CONCLUSIONS: We have shown that the left ventricular T((MRC)) increases after developed heart failure. The increase in T((MRC)) was independent on loading conditions and thus have a potential for a contractility index. 相似文献
3.
M A Kielhofner G Schnell T T Schubert D Kebede-Daniels 《Journal of clinical gastroenterology》1987,9(6):697-700
An 83-year-old woman with no history of vascular surgery presented with a fatal upper gastrointestinal bleed from an aortogastric fistula secondary to a penetrating gastric ulcer. The fistula was between the thoracic aorta and the gastric ulcer in a hiatus hernia. On autopsy, a discrete 1-cm ulcer had perforated into the otherwise normal thoracic aorta. Aortogastric fistula involving the thoracic aorta and a gastric ulcer is rare in the absence of vascular graft surgery or aneurysm. We review the pertinent literature. 相似文献
4.
Christopher R Pryce Andrea C Dettling Marianne Spengler Christian R Schnell Joram Feldon 《Neuropsychopharmacology》2004,56(2):72-79
BACKGROUND: Early environment is a major determinant of long-term mental health, evidenced by the relationship between early-life neglect or abuse and chronically increased vulnerability to developmental psychopathology, including major depressive disorder (MDD). Animal studies can increase understanding of environmentally mediated causal risk processes. We describe how daily deprivation of biological parenting in primate infants disrupts development of homeostatic and reward systems central to MDD. METHODS: Nine breeding pairs of marmoset monkeys provided control twins (CON) and early-deprived twins (ED); the latter were socially isolated for 30-120 min/day on days 2-28. During the first year of life, basal urinary norepinephrine (NE) titers and cardiophysiologic activity were measured. At the end of year 1 (adolescence), automated neuropsychologic tests were conducted to measure responsiveness to changes in stimulus-reward association (simple/reversed visual discrimination learning) and to reward per se (progressive ratio [PR] reinforcement schedule). RESULTS: The ED monkeys exhibited increased basal urinary NE titers and increased systolic blood pressure relative to CON siblings. The ED monkeys required more sessions to reinstate stimulus-oriented behavior following reversal, suggesting increased vulnerability to perceived loss of environmental control; ED monkeys also performed less PR operant responses, indicating that reward was less of an incentive and that they were mildly anhedonic relative to CON. CONCLUSIONS: In marmoset monkeys, neglect-like manipulation of ED leads to chronic changes in homeostatic systems, similar to those in children and adolescents exposed to early-life adversity and in MDD, and to responses to environmental stimuli similar to those that characterize MDD. 相似文献
5.
Bente E. Moen Bjrg E. Hollund Morten Berntsen Ragnar Flo Knut Rasmus Kyvik Trond Riise 《American journal of industrial medicine》1995,27(4):555-564
Occupational exposure to carcinogenic agents on the decks on six Norwegian crude oil tankers was examined in five harbors. The purpose of the study was to evaluate the need for improving the working environment on deck on these tankers. Technical arrangments and the work itself on the deck were observed during loading or unloading. Occupational monitoring was performed by active sampling of benzene, polyaromatic hydrocarbons, and some aldehydes. The crew answered a questionnaire concerning their work, use of protective equipment, and occurrence of acute symptoms. The levels of air-borne carcinogenic agents were low, probably due to closed loading systems on all tankers. However, the seamen reported discomfort during the work that may be related to other chemical agents in the cargo. The seamen were frequently painting with lead chromate paint without using personal protective equipment. This type of chemical exposure should be evaluated. 相似文献
6.
7.
A. Aamodt J. Lund-Larsen J. Eine E. Andersen P. Benum O. Schnell Husby 《Journal of orthopaedic research》1997,15(6):927-931
Two conflicting theories exist concerning the stress pattern for the proximal lateral aspect of the human femur. According to the classic theory of Pauwels, a bending moment on the femur leads to compression medially and to tension laterally. The alternative theory is that muscle forces contribute to a moment-free loading of the femur, with both the medial and lateral cortices subjected to compression. To examine these theories, we measured the strain at the external surface of the proximal lateral aspect of the femur of two female patients undergoing surgery for “snapping hip syndrome.” During the surgical procedure, a strain-gauge rosette was bonded to the lateral aspect of the femur and the cortical strains were monitored while the patient performed a series of activities. In both patients, principle tensile strain increased significantly during one-legged stance, walking, and stair climbing as compared with that during two-legged stance. During each loading situation, the principal tensile strain was aligned within 22° to the longitudinal femoral axis. Dynamic strain measurements consistently revealed tensile axial strain at the lateral aspect of the femur during each activity. The present studv supports the classic bending theory of Pauwels and demonstrates that the proximal lateral aspect of the femur is subjected to tension during the stance phase of gait. 相似文献
8.
T. J. Vogl S. Steiner B. Schnell A. Gerbes C. McMahon C. Wilimzig J. Lissner 《European radiology》1992,2(4):310-316
Twenty-nine patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI was performed using T1- and T2-weighted spin-echo sequences as well as fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). in patients with hepatitis, MRI could be used in guiding liver biopsies as inflammatory changes were clearly delineated. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. On the other hand MRI was more helpful in differentiating fatty changes and neoplasm. In liver cirrhosis, fibrotic changes were most clearly demonstrated by MRI. In patients suffering from hemochromatosis MRI offers advantages over CT and ultrasound in the diagnosis and follow up due to the paramagnetic properties of iron, resulting in a reduction in signal intensity. In patients with Wilson's disease a characteristic pattern of parenchymal changes was seen. Administration of Gd- DTPA contributes additional information about perfusion conditions in the liver parenchyma, however this information was not of diagnostic relevance in the cases we studied.
Correspondence to: T.J. Vogl 相似文献
9.
Knut A. Selvig Ulf M. E. Wikesjö Gary C. Bogle Richard D. Finkelman 《Journal of clinical periodontology》1994,21(6):380-385
Abstract. Effects of a topically applied growth factor combination on fibroblast migration, collagen fiber formation and bone regeneration were studied in standardized periodontal defects in 4 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and into the dentin of maxillary and mandibular teeth. Collagen sponges, impregnated with 200 ng insulin-like growth factor II, 20 ng basic fibroblast growth factor and 6 ng transforming growth factor beta 1 were fitted to defects randomly in right or left quadrants and the flaps repositioned and sutured. Contralateral control defects received the collagen with vehicle only. Experimental procedures were staggered to allow observations of healing 3, 7, 10, and 14 days after surgery. Histometric analysis showed no differences in fibroblast and collagen density between control and growth factor defects. Bone regeneration was significantly greater in control than in growth factor defects 10 and 14 days after surgery. The rate of healing generally appeared more affected by intra-dog variations or procedural variations than by the growth factor combination. 相似文献
10.
This article describes recent developments in cardiology and cardiovascular disease that are likely to be relevant to primary healthcare professionals and their patients. The following subject areas are covered: Primary prevention: recent developments in pharmaco-logical interventions, drug interactions, and drugs that are likely to cause harm; cardiovascular risk estimation and shared decision making with patients; and new developments in 24-hour ambulatory blood pressure monitoring. Secondary prevention: new models of care, including nurse-led care for the provision of hypertension and secondary prevention clinics; new drugs for the treatment of angina and myocardial infarction; ambulatory electrocardiography for the diagnosis of arrhythmias in primary care; and new developments in the treatment of atrial fibrillation - direct thrombin inhibitors and implantable devices. Tertiary prevention: recent developments in cardiac rehabilitation; recent evidence concerning revascularisation procedures and appropriateness criteria for referral; and implantable defibrillators. 相似文献