全文获取类型
收费全文 | 1025篇 |
免费 | 50篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 40篇 |
妇产科学 | 15篇 |
基础医学 | 173篇 |
口腔科学 | 22篇 |
临床医学 | 135篇 |
内科学 | 148篇 |
皮肤病学 | 16篇 |
神经病学 | 197篇 |
特种医学 | 16篇 |
外科学 | 85篇 |
综合类 | 4篇 |
预防医学 | 55篇 |
眼科学 | 3篇 |
药学 | 50篇 |
肿瘤学 | 103篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 22篇 |
2020年 | 22篇 |
2019年 | 26篇 |
2018年 | 30篇 |
2017年 | 17篇 |
2016年 | 32篇 |
2015年 | 25篇 |
2014年 | 42篇 |
2013年 | 48篇 |
2012年 | 104篇 |
2011年 | 103篇 |
2010年 | 70篇 |
2009年 | 49篇 |
2008年 | 67篇 |
2007年 | 75篇 |
2006年 | 53篇 |
2005年 | 62篇 |
2004年 | 58篇 |
2003年 | 45篇 |
2002年 | 48篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 12篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1969年 | 1篇 |
1894年 | 1篇 |
排序方式: 共有1077条查询结果,搜索用时 15 毫秒
1.
2.
Annemieke C. Kole MD Omgo E. Nieweg MD PhD Robert J. van Ginkel MD Jan Pruim MD PhD Harald J. Hoekstra MD PhD Anne M. J. Paans PhD Willem Vaalburg PhD Dr. Heimen Schraffordt Koops MD PhD 《Annals of surgical oncology》1997,4(1):57-63
Background: It is often difficult to detect a local recurrence of soft-tissue sarcomas due to disturbance of the normal anatomy by previous
surgery and radiotherapy. The aim of this study was to assess the value of positron emission tomography (PET) with [18F]fluoro-2-deoxy-d-glucose (FDG) for detecting local recurrences.
Methods: In the period 1992–1995, 17 patients with proven or suspected local recurrence of soft-tissue sarcoma were examined using
FDG-PET. Fifteen of these patients were ultimately proven to have a recurrence.
Results: Recurrence was visualized in 14 patients (93%). Small tumors (maximum diameter 0.5 cm) were as easily visible as large lesions
(maximum diameter 20 cm). In one patient the PET scan was positive, but the recurrence could not be proven histologically.
Recurrence was proven 1 year later. A recurrent low-grade liposarcoma was not visualized. The two patients with benign lesions
had a negative PET scan. The mean glucose metabolic rate was calculated to be 13.2 μmol/100 g/min (range 1.9–28.4). A correlation
was found between the histological malignancy grade and the metabolic rate (p<0.05; Kruskal-Wallis).
Conclusion: PET with FDG is a useful addition to the diagnostic armamentarium for detecting local recurrence of soft-tissue sarcomas
and provides an indication of the malignancy grade of the recurrent lesion.
Presented at the 47th Annual Meeting of The Society for Surgical Oncology, Houston, Texas, March 17–20, 1994. 相似文献
3.
Arne Popma Robert Vermeiren Charlotte A M L Geluk Thomas Rinne Wim van den Brink Dirk L Knol Lucres M C Jansen Herman van Engeland Theo A H Doreleijers 《Neuropsychopharmacology》2007,61(3):405-411
BACKGROUND: In animals, strong evidence exists for an association between testosterone and aggression. In humans, and particularly in children and adolescents, findings have been less consistent. Previous research has suggested that this may partly be due to moderating effects of other factors, e.g., hormones. This study aims to investigate the moderating effect of cortisol on the relationship between testosterone and subtypes of aggression in delinquent male adolescents. METHODS: Participants were 103 boys (mean age 13.7) referred to a delinquency diversion program. Testosterone and cortisol levels were determined from saliva samples collected during resting conditions and related to self-report scores on overt and covert aggression. RESULTS: Linear regression analyses revealed a significant interaction between cortisol and testosterone in relation to overt aggression, with a significant positive relationship between testosterone and overt aggression in subjects with low cortisol levels but not in subjects with high cortisol levels. Using the same model for covert aggression, no significant effects of testosterone, cortisol, or testosterone x cortisol interaction were found. CONCLUSIONS: These results indicate a moderating effect of cortisol on the relationship between testosterone and overt aggression in delinquent male adolescents. Implications and directions for future research are discussed. 相似文献
4.
Michael Groeneweg Suzan Tan Annemieke M. Boot Johan C. de Jongste Jan Bouquet Maarten Sinaasappel 《Journal of cystic fibrosis》2002,1(4):583-280
BACKGROUND: Assessment of nutritional status in children with cystic fibrosis (CF) is clinically relevant. Methods to measure nutritional status should be reliable and non-invasive, and reference values should be available. AIM: To compare weight and height measurements and measurements of specific body compartments in children with CF. METHODS: In a cross-sectional survey of 58 children with CF (28 females), we compared height and weight (expressed as: weight-for-height, body mass index (BMI), height-for-age and weight-for-age) with fat mass (skinfold sum (SFS)), muscle mass (upper arm circumference (UAC)) and bioelectrical impedance analysis (BIA). Results were expressed as Z-scores, using Dutch reference values. RESULTS: BMI and weight-for-height were within the normal range (mean Z-score (range): -0.13 (-1.5, 2.7) and -0.02 (-1.7, 2.8)). Weight and height corrected for age were below normal (mean Z-score (range): -0.79 (-2.4, -0.05) and -1.2 (-2.8, 1.4) (P<0.01)). Lean body mass by skinfold sum (LBM(sfs)), UAC and BIA were also significantly below reference values (mean Z-score (range): -0.9 (-2.2, 1.8), -0.95 (-2.4, 1.8) and -1.1 (-3.6, 1.0) (P<0.01)). Lean body mass (LBM) by BIA correlated with LBM(sfs). BIA systematically underestimated LBM in both CF patients and in control subjects. CONCLUSION: Nutritional status of children with CF must be evaluated, using age-corrected weight and height expressed in Z-score. LBM estimated by SFS, UAC and by BIA appear to be useful, although longitudinal studies in CF children should be performed to evaluate their clinical significance in detecting changes in nutritional status. 相似文献
5.
The catecholamines norepinephrine and epinephrine are used by the sympathetic nervous system to communicate with other organ systems, including the immune system. Adrenergic receptors on target cells bind these catecholamines and modulate the activity of the target cell. The beta 2-adrenergic receptor is the most abundantly expressed and best studied adrenergic receptor in the immune system. Here, I summarize data from our own laboratory and from others on the expression and possible function of alpha 1-adrenergic receptors in the immune system. alpha 1-Adrenergic receptor expression in the immune system can be regulated by glucocorticoids, by beta 2-adrenergic agonists, and by cytokines. In addition, the possible pathophysiological implications of the expression of alpha 1-adrenergic receptors on immune cells from arthritis patients are discussed. 相似文献
6.
Vanholder R Dhondt A 《BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy》1999,11(6):417-429
The last decade has been characterised by the development of several anticoagulation methods as alternatives to the heparins. One of these is the antithrombin hirudin, which is now available on a large scale in the recombinant form. The application of hirudin as an anticoagulant in haemodialysis has been complicated by the decrease of its clearance in patients with renal failure. The half-life of hirudin is more than 30 times longer in haemodialysis patients than in healthy subjects. Therefore, at present, its use in the haemodialysis setting is essentially limited to heparin-induced thrombocytopenia (HIT). Hirudin has been used sporadically and with success in nonrenal failure patients with HIT and at least once on a regular basis in a haemodialysis patient. A starting dose between 0.08 and 0.15 mg/kg for the first dialysis, followed by 50% of this quantity during the following dialyses is recommended. Hirudin activity can be monitored by aiming for threshold activated partial thromboplastin time (aPTT) values between 60 and 90 seconds, with urgent dosage adaptations once aPTT rises above 100 to 120 seconds. Hirudin concentrations during dialysis should be maintained between 400 and 1000 microg/L, with determination by ecarin clotting time or chromogenic assays. At present, the use of hirudin is also limited by the absence of an effective antidote. In studies in humans, no enhanced removal of hirudin was observed during dialysis with large pore dialysers in contrast to earlier published animal studies. 相似文献
7.
Quantitative flow cytometric analysis of opsonophagocytosis and killing of nonencapsulated Haemophilus influenzae by human polymorphonuclear leukocytes. 总被引:3,自引:0,他引:3 下载免费PDF全文
L Vogel L van Alphen F Geluk A Troelstra E Martin R Bredius P Eijk H Jansen J Dankert 《Clinical and Vaccine Immunology : CVI》1994,1(4):394-400
Since nonencapsulated Haemophilus influenzae persists in the lower respiratory tracts of patients with chronic bronchitis despite the presence of specific antibodies, complement, and polymorphonuclear leukocytes (PMNs), opsonophagocytosis of H. influenzae was analyzed. Nonencapsulated H. influenzae isolated from the sputa of chronic bronchitis patients was labeled with fluorescein isothiocyanate and incubated with human PMNs in the presence of complement and antibodies for 30 min at 37 degrees C. Candida albicans was added to each sample as an internal standard, and the reduction of the number of bacteria was determined by flow cytometry. Fluorescence quenching with ethidium bromide was used to discriminate between intracellular and extracellular bacteria. Opsonophagocytosis of viable H. influenzae d1 was 17% +/- 29% in the presence of complement and human pooled sera containing high titers of strain-specific antibodies. Opsonophagocytosis of six other H. influenzae strains was also poor. Under the same conditions, opsonophagocytosis of Staphylococcus aureus was 90% +/- 5%, and opsonophagocytosis of C. albicans was 55% +/- 23%. About half of the number of H. influenzae bacteria associated with PMNs was internalized. Opsonophagocytosis of heat-killed H. influenzae d1 (41% +/- 20%) was higher than that of viable bacteria of the same strain (P < 0.05). This result suggests that the accessibility of epitopes on H. influenzae for opsonizing antibodies is better on killed than on viable bacteria. We conclude that viable nonencapsulated H. influenzae is poorly opsonophagocytized in the presence of strain-specific antibodies and complement. 相似文献
8.
Rensink AA Otte-Höller I de Boer R Bosch RR ten Donkelaar HJ de Waal RM Verbeek MM Kremer B 《Neurobiology of aging》2004,25(1):93-103
Amyloid-beta (Abeta) deposition in the cerebral arterial and capillary walls is one of the characteristics of Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis-Dutch type. In vitro, Abeta1-40, carrying the "Dutch" mutation (DAbeta1-40), induced reproducible degeneration of cultured human brain pericytes (HBP), by forming fibrils at the cell surface. Thus, this culture system provides an useful model to study the vascular pathology seen in Alzheimer's disease. In this study, we used this model to investigate the effects of insulin on Abeta-induced degeneration of HBP, as it has been mentioned previously that insulin is able to protect neurons against Abeta-induced cell-death. The toxic effect of DAbeta1-40 on HBP was inhibited by insulin in a dose-dependent matter. Insulin interacted with Abeta and inhibited fibril formation of Abeta in a cell-free assay, as well as at the cell surface of HBP. Our data indicate that the formation of a fibril network is essential for Abeta-induced cell death in HBP. Additionally, insulin may be involved in the regulation of Abeta fibrillization in AD. 相似文献
9.
Rutger L. van Bezooijen Marco C. DeRuiter Nathalie Vilain Rui M. Monteiro Annemieke Visser Lianne van der Wee‐Pals Conny J. van Munsteren Pancras C.W. Hogendoorn Michel Aguet Christine L. Mummery Socrates E. Papapoulos Peter Ten Dijke Clemens W.G.M. Löwik 《Developmental dynamics》2007,236(2):606-612
Spatial-temporal regulation of bone morphogenetic protein (BMP) and Wnt activity is essential for normal cardiovascular development, and altered activity of these growth factors causes maldevelopment of the cardiac outflow tract and great arteries. In the present study, we show that SOST, a Dan family member reported to antagonize BMP and Wnt activity, is expressed within the medial vessel wall of the great arteries containing smooth muscle cells. The ascending aorta, aortic arch, brachiocephalic artery, common carotids, and pulmonary trunk were all associated with SOST expressing smooth muscle cells, while the heart itself, including the valves, and more distal arteries, that is, pulmonary arteries, subclavian arteries, and descending aorta, were negative. SOST was expressed from embryonic day 15.5 up to the neonatal period. SOST expression, however, did not correspond with inhibition of Smad-dependent BMP activity or beta-catenin-dependent Wnt activity in the great arteries. Activity of both signaling pathways was already down-regulated before induction of SOST expression. 相似文献
10.
H S Hiemstra P A van Veelen A Geluk N C Schloot R R de Vries T H Ottenhoff B O Roep J W Drijfhout 《Vaccine》1999,18(3-4):204-208
Mimicry epitopes that are recognized by T-cells can be identified through screening of synthetic peptide libraries. We have shown that these mimicry epitopes share sequence similarity with the corresponding natural epitopes and that mimicry sequences can be used for the definition of protein derived T-cell epitopes from databases. This can be done by either homology searching or pattern searching. Here we discuss the advantages and disadvantages of homology searching as an alternative for the generally applicable recognition pattern approach. We show that only for part of the library derived mimicry epitopes, the degree of similarity to the natural epitope may be high enough for successful homology searching in small databases. 相似文献