全文获取类型
收费全文 | 1113篇 |
免费 | 67篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 28篇 |
妇产科学 | 46篇 |
基础医学 | 105篇 |
口腔科学 | 12篇 |
临床医学 | 66篇 |
内科学 | 309篇 |
皮肤病学 | 18篇 |
神经病学 | 88篇 |
特种医学 | 25篇 |
外科学 | 259篇 |
综合类 | 10篇 |
预防医学 | 73篇 |
眼科学 | 6篇 |
药学 | 61篇 |
中国医学 | 11篇 |
肿瘤学 | 66篇 |
出版年
2023年 | 3篇 |
2022年 | 21篇 |
2021年 | 34篇 |
2020年 | 11篇 |
2019年 | 29篇 |
2018年 | 30篇 |
2017年 | 19篇 |
2016年 | 16篇 |
2015年 | 34篇 |
2014年 | 45篇 |
2013年 | 59篇 |
2012年 | 93篇 |
2011年 | 80篇 |
2010年 | 46篇 |
2009年 | 33篇 |
2008年 | 51篇 |
2007年 | 47篇 |
2006年 | 56篇 |
2005年 | 50篇 |
2004年 | 58篇 |
2003年 | 39篇 |
2002年 | 53篇 |
2001年 | 28篇 |
2000年 | 35篇 |
1999年 | 24篇 |
1998年 | 13篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 19篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1969年 | 3篇 |
1966年 | 2篇 |
1947年 | 5篇 |
排序方式: 共有1186条查询结果,搜索用时 15 毫秒
41.
42.
43.
Constrained Markov control processes with randomized discounted cost criteria: infinite linear programming approach
下载免费PDF全文
![点击此处可从《Optimal control applications & methods.》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Juan González‐Hernández Raquiel R. López‐Martínez J. Adolfo Minjárez‐Sosa J. Rigoberto Gabriel‐Arguelles 《Optimal control applications & methods.》2014,35(5):575-591
In this paper, we study constrained Markov control processes on Borel spaces with possibly unbounded one‐stage cost, under a discounted optimality criterion with random discount factor and restrictions of the same kind. We prove that the corresponding optimal control problem is equivalent to an infinite‐dimensional linear programming problem. In addition, considering the dual program, we show that there is no duality gap, and moreover, the strong duality condition holds. Hence, both programs are solvable, and their optimal values coincide. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
44.
45.
46.
Prefrontal cortex,hippocampus, and basolateral amygdala plasticity in a rat model of autism spectrum
Nuvia Sosa‐Díaz Maria Elena Bringas Marco Atzori Gonzalo Flores 《Synapse (New York, N.Y.)》2014,68(10):468-473
We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) at embryonic day 12.5 on the anatomical properties of the prefrontal cortex, hippocampus, and basolateral amygdala, at three different ages: immediately after weaning (postnatal day 21 [PD21]), prepubertal (PD35), and postpubertal (PD70) ages in a rat model of autistic spectrum disorder. Quantitative analysis of the thickness of the prefrontal cortex revealed a reduced size at all study ages in the cingulate 1 area of the prefrontal cortex and CA1 of the dorsal hippocampus in prenatally exposed animals compared to controls. At the level of the basolateral amygdala, a reduction in the size was observed at PD35 and PD70 in the VPA group. In addition, a reduced thickness was observed in the prelimbic region of the prefrontal cortex in VPA animals at PD35. Interestingly, no differences in cortical thickness were observed between control and VPA animals in the infralimbic region of the prefrontal at any age. Our results suggest that prenatal exposure to VPA differentially alters cortical limbic regions anatomical parameters, with implication in the autistic spectrum disorder. Synapse 68:468–473, 2014 . © 2014 Wiley Periodicals, Inc. 相似文献
47.
Lauren Gratian MD John Pura MPH Michaela Dinan PhD Shelby Reed PhD Randall Scheri MD Sanziana Roman MD Julie Ann Sosa MD 《Annals of surgical oncology》2014,21(11):3509-3514
Background
Adrenocortical carcinoma (ACC) is a rare, aggressive disease with no apparent change in treatment or survival in the United States over the past two decades. Our objective was to determine whether treatment patterns or clinical outcomes vary by hospital case volume.Methods
Patients with ACC were identified from the National Cancer Database (1998–2011). High-volume centers (HVCs) were defined by a case load of ≥4 cases of primary adrenal malignancy annually, which corresponded to the 90th percentile. All other facilities were considered low-volume centers (LVCs).Results
A total of 2,765 ACC patients were treated across 1,046 facilities. Compared to patients treated at LVCs, patients treated at HVCs were younger (50 vs. 54 years), with larger tumors (11.2 vs. 10.5 cm), and underwent higher rates of surgery (78.8 vs. 73.4 %), radical resection (17.3 vs. 13.9 %), regional lymph node evaluation (23.2 vs. 18.8 %), and chemotherapy including mitotane (43.8 vs. 31.0 %, all p < 0.05).There were no significant differences in median length of stay (5 vs. 5 days), 30-day readmission rates (4.0 % for HVCs vs. 3.9 % for LVCs), or 30-day postoperative mortality rates (1.9 % for HVCs vs. 3.7 % for LVCs). Median overall survival was 2.0 years for HVCs and 1.9 years for LVCs, p = 0.53. After adjusting for patient and tumor characteristics, overall survival did not differ significantly between patients treated at HVCs versus LVCs [HR = 0.89 (95 % confidence interval 0.70, 1.12)].Conclusions
Treatment at HVCs was associated with more aggressive surgical resection and chemotherapy use. Prognosis remained poor despite more aggressive treatment. 相似文献48.
R P Witherspoon R Storb H D Ochs N Fluornoy K J Kopecky K M Sullivan J H Deeg R Sosa D R Noel K Atkinson E D Thomas 《Blood》1981,58(2):360-368
One-hundred fifty-three recipients of HLA-identical sibling marrow transplants for aplastic anemia or hematologic malignancy were injected with bacteriophage phi X174 (phage), pneumococcal polysaccharide antigen (PPA), or keyhole limpet hemocyanin (KLH). Antibody levels were determined several times in the 6 wk after injection. Multiple regression techniques were used to determine what factors played significant roles in the antibody response. The most significant factors were the time elapsed from transplantation, chronic graft- versus-host disease (GVHD), and antithymocyte globulin (ATG) treatment. All patients had low antibody responses to all antigens in the first 180 days from transplant. Beyond 180 days patients without chronic GVHD showed antibody responses indistinguishable from those of normal donors. However, patients with chronic GVHD had the following impairments: (1) primary response to phage, (2) conversion from IgM to IgG in secondary response to phage, (3) secondary response to KLH, and (4) response to PPA. ATG treatment given to patients either prophylactically or therapeutically for acute GVHD was followed by lower primary responses to phage in the first 180 days and poor ability to switch from IgM to IgG antibody in the secondary response beyond 180 days postgrafting. Other factors did not yield additional significant information about ability to predict antibody responses including diagnosis, conditioning regimen, treatment in or out of laminar air flow rooms, transplantation, pretransplant refractoriness of the recipient to platelet transfusions from random donors, donor age or donor sex, and steroid administration for treatment for prevention of GVHD. The data indicate that, given enough time after transplantation, the ability to produce normal antibody function recovers except in those patients experiencing chronic GVHD. 相似文献
49.
Arós F Boraita A Alegría E Alonso AM Bardají A Lamiel R Luengo E Rabadán M Alijarde M Aznar J Baño A Cabañero M Calderón C Camprubí M Candell J Crespo M de la Morena G Fernández A Ferrero JA Gayán R Bolao IG Hernández M Maceira A Marín E Muela de Lara A Placer L San Román JA Serratosa L Sosa V Subirana MT Wilke M 《Revista espa?ola de cardiología》2000,53(8):1063-1094
Most exercise testing is performed in adults with known or suspected ischemic heart disease. In the last few years cardiac imaging techniques have been applied in this field, improving the information obtained with the procedure. However, the exceptions to this rule are emerging rapidly not only in healthy people (asymptomatic individuals, athletes, handicapped people) but also in cardiac patients (advanced congestive heart failure, hypertension, rhythm disorders, congenital heart disease, etc.). All the-se issues justify the need for a multidisciplinary consensus document in Spain.This paper reviews and updates the methodological aspects of the stress test, including those related to oxygen consumption measurements. The main aim of this review was to determine the role of exercise testing in the evaluation of ischemic heart disease as well as the applications of imaging stress testing. The usefulness of this test in other non-ischemic cardiac disorders and in selected subsets of healthy people is also reviewed. 相似文献
50.
Laura MaciasMuoz Beatriz FradeSosa Jose IniciarteMundo Susana Hidalgo Rosa Maria Morla Yadira Gallegos Raimon Sanmarti Josep Maria Auge 《Journal of clinical laboratory analysis》2022,36(3)
BackgroundCalprotectin is a calcium‐binding protein that can be measured in serum, plasma, and feces. Increased serum and plasma calprotectin concentrations have been found in chronic inflammatory rheumatic disorders. An analytical and clinical evaluation of the DiaSorin Liaison® fecal Calprotectin assay using LIAISON® XL was performed.MethodsThe protocol included an analytical and clinical evaluation in which imprecision, the linearity of dilution, differences between serum and plasma samples and method comparison with CalproLab™ ELISA kit were assessed. Serum calprotectin concentrations in active (n = 26) and remission (n = 23) rheumatoid arthritis (RA) patients were compared.ResultsThe intra‐day and inter‐day analytical imprecision CVs ranged from 2.9% to 4.0% and 2.7% to 10.4%, respectively. Correlation between measured and expected values was high (R > 0.99), indicating good linearity. The Wilcoxon signed‐rank test showed that serum and plasma matched samples presented statistically significant differences (p < 0.001) being the highest concentrations of calprotectin observed in serum samples. Deming regression equation was as follows: Diasorin calprotectin (μg/ml) = −0.32 (95% CI: −0.65 ‐ −0.05) +1.58 (95% CI: 1.42–1.79).* Calprolab calprotectin (μg/ml). Significantly higher serum calprotectin levels were found in RA patients with active disease when compared to patients with low disease activity or in clinical remission (mean ± SD) [(3.35 μg/ml ± 1.55) vs. (1.63 μg/ml ± 0.52), p < 0.001] and these levels correlated well with all disease activity indices.ConclusionsThe DiaSorin Liaison® fecal Calprotectin assay adapted for serum samples showed adequate technical performances and the clinical performances were similar to other assays. 相似文献