全文获取类型
收费全文 | 1002篇 |
免费 | 84篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 11篇 |
妇产科学 | 15篇 |
基础医学 | 155篇 |
口腔科学 | 6篇 |
临床医学 | 128篇 |
内科学 | 218篇 |
皮肤病学 | 10篇 |
神经病学 | 120篇 |
特种医学 | 18篇 |
外科学 | 132篇 |
综合类 | 3篇 |
一般理论 | 1篇 |
预防医学 | 61篇 |
眼科学 | 16篇 |
药学 | 89篇 |
中国医学 | 5篇 |
肿瘤学 | 92篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 33篇 |
2021年 | 62篇 |
2020年 | 36篇 |
2019年 | 37篇 |
2018年 | 32篇 |
2017年 | 39篇 |
2016年 | 43篇 |
2015年 | 43篇 |
2014年 | 41篇 |
2013年 | 57篇 |
2012年 | 63篇 |
2011年 | 80篇 |
2010年 | 39篇 |
2009年 | 33篇 |
2008年 | 95篇 |
2007年 | 59篇 |
2006年 | 61篇 |
2005年 | 46篇 |
2004年 | 49篇 |
2003年 | 39篇 |
2002年 | 30篇 |
2001年 | 2篇 |
1999年 | 3篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有1090条查询结果,搜索用时 125 毫秒
51.
Sergei Vlassov Sven Oras Martin Timusk Veronika Zadin Tauno Tiirats Ilya M. Sosnin Rünno Lhmus Artis Linarts Andreas Kyritsakis Leonid M. Dorogin 《Materials》2022,15(5)
Polydimethylsiloxane (PDMS) is the most widely used silicon-based polymer due to its versatility and its various attractive properties. The fabrication of PDMS involves liquid phase cross-linking to obtain hydrophobic and mechanically flexible material in the final solid form. This allows to add various fillers to affect the properties of the resulting material. PDMS has a relatively low Thermal Conductivity (TC), in the order of 0.2 W/mK, which makes it attractive for thermal insulation applications such as sealing in construction. Although a further decrease in the TC of PDMS can be highly beneficial for such applications, most research on the thermal properties of PDMS composites have focused on fillers that increase the TC rather than decrease it. In the present work, we propose a simple and reliable method for making a PDMS-based composite material with significantly improved thermal insulation properties, by adding hollow glass microspheres (HGMs) to the mixture of the liquid base and the cross-linker (10:1 ratio), followed by degassing and heat-assisted crosslinking. We obtained a 31% reduction of thermal conductivity and a 60% increase in the elastic modulus of samples with HGM content of 17% by weight. At the same time, the sound insulation capacity of the PDMS-HGM composite is slightly decreased in comparison to pure PDMS, as a result of its lower density. Finally, the wettability of the samples had no dependence on HGM content. 相似文献
52.
53.
Andrei A. Savchenko Elena Tikhonova Igor Kudryavtsev Dmitry Kudlay Ilya Korsunsky Vasily Beleniuk Alexandr Borisov 《Viruses》2022,14(3)
Background: T and B cell-mediated immunity can be assessed using T cell receptor excision circle (TREC) and Kappa-deleting recombination excision circle (KREC) analysis, respectively, and successful implementation of this method requires evaluation of the correlation between the TREC frequencies and T cell subsets as well as KREC levels and B lymphocyte subsets. The aim of the present study was to evaluate the correlation between the TREC/KREC concentrations and T/B lymphocyte subsets at different stages of COVID-19. Methods: We examined 33 patients in the acute stage of COVID-19 (including 8 patients with poor outcomes) and 33 COVID-19 survivors. TREC/KREC concentrations were measured using quantitative real-time PCR. T/B lymphocyte subsets were determined using flow cytometry. Results: Blood TREC and KREC levels were found to be significantly lower in the acute stage of COVID-19 compared to control values. Moreover, a zero blood TREC level was a predictor of a poor disease outcome. Reductions in CD3+CD4+CD45RO−CD62L− and CD3+CD8+CD45RO−CD62L− T cell counts (as well as in the main fractions of B1 and B2 B cells) indicated a favorable outcome in COVID-19 patients in the acute stage of the disease. Decreased CD3+CD4+CD45RO−CD62L+ and CD3+CD8+CD45RO−CD62L+ T cell frequencies and increased CD3+CD8+CD45RO−CD62L− cell counts were found to indicate a poor outcome in patients with acute COVID-19. These patients were also found to have increased B1 cell counts while demonstrating no changes in B2 cell counts. The levels of effector T cell subsets an naïve B cells were normal in COVID-19 survivors. The most pronounced correlations between TREC/KREC levels and T/B cell subsets counts were observed in COVID-19 survivors: there were positive correlations with naïve T and B lymphocytes and negative correlations with central and effector memory T cell subsets. Conclusions: The assessment of correlations between TREC and T cell subsets as well as KREC levels and B cell subset counts in patients with acute COVID-19 and COVID-19 survivors has shown that blood concentrations of TREC and KREC are sensitive indicators of the stage of antigen-independent differentiation of adaptive immunity cells. The results of the TREC and KREC analysis correlated with the stages of COVID-19 and differed depending on the outcome of COVID-19. 相似文献
54.
Vassiliy A. Medvedev Ilya E. Kolesnikov Pavel K. Olshin Mikhail D. Mikhailov Alina A. Manshina Daria V. Mamonova 《Materials》2022,15(7)
Optical materials doped with several lanthanides are unique in their properties and are widely used in various fields of science and technology. The study of these systems provides solutions for noncontact thermometry, bioimaging, sensing technology, and others. In this paper, we report on the demonstration of YVO4 nanoparticles doped with one, two, and three different rare earth ions (Tm3+, Er3+, and Nd3+). We discuss the morphology, structural properties, and luminescence behavior of particles. Luminescence decay kinetics reveal the energy transfer efficiency (up to 78%) for different ions under the selective excitation of individual ions. Thus, we found that the energy transition from Tm3+ is more favorable than from Er3+ while we did not observe any significant energy rearrangement in the samples under the excitation of Nd3+. The observed strong variation of REI lifetimes makes the suggested nanoparticles promising for luminescent labeling, anticounterfeiting, development of data storage systems, etc. 相似文献
55.
Liran Statlender Orit Raphaeli Itai Bendavid Moran Hellerman Ilya Kagan Guy Fishman Pierre Singer 《Nutrients》2022,14(7)
Introduction. Hypophosphatemia may prolong ventilation and induce weaning failure. Some studies have associated hypophosphatemia with increased mortality. Starting or restarting nutrition in a critically ill patient may be associated with refeeding syndrome and hypophosphatemia. The correlation between nutrition, mechanical ventilation, and hypophosphatemia has not yet been fully elucidated. Methods. A retrospective cohort study of 825 admissions during two consecutive years was conducted. Using the electronic medical chart, demographic and clinical data were obtained. Hypophosphatemia was defined as a phosphate level below 2.5 mg/dL (0.81 mmol/L) in the first 72 h of ICU admission. Comparisons between baseline characteristics and outcomes and multivariate analysis were performed. Results. A total of 324 (39.27%) patients had hypophosphatemia during the first 72 h of ICU admission. Patients with hypophosphatemia tended to be younger, with lower APACHE-II, SOFA24, and ΔSOFA scores. They had a longer length of stay and length of ventilation, more prevalent prolonged ventilation, and decreased mortality. Their energy deficit was lower. There was no effect of hypophosphatemia severity on these results. In multivariate analysis, hypophosphatemia was not found to be statistically significant either with respect to mortality or survivor’s length of ventilation, but lower average daily energy deficit and SOFA24 were found to be statistically significant with respect to survivor’s length of ventilation. Conclusion. Hypophosphatemia had no effect on mortality or length of ventilation. Lower average daily energy deficit is associated with a longer survivor’s length of ventilation. 相似文献
56.
Ilya Ioslovich Per-Olof Gutman Ido Seginer 《Optimal control applications & methods.》1996,17(3):157-169
A simplified non-linear dynamic model of greenhouse crop growth with constraints on the state and the control signal is considered. The weather is assumed to be known. The optimization criterion is to minimize the heating and ventilation cost. In this paper a novel solution is presented for the case when both the heating cost and the ventilation cost are included in the criterion. Important properties of the optimal solutions are clarified. It is found that neighbouring maxima and minima of a particular function of the outside temperature, the solar radiation and the heat transfer coefficient decide whether heating or ventilation has to be applied. A numerical example is given. 相似文献
57.
Elena V. Preobrazhenskaya Aglaya G. Iyevleva Amina M. Suleymanova Vladislav I. Tiurin Natalia V. Mitiushkina Ilya V. Bizin Alexandr O. Ivanstov Olga A. Gorustovich Kseniya V. Shelekhova Denis Y. Kachanov Svetlana R. Varfolomeeva Vitaliy Y. Roschin Anna N. Kazakova Dmitriy V. Litvinov Tatiana V. Shamanskaya Nikita A. Savelov Evgeny N. Suspitsin Evgeny N. Imyanitov 《Pediatric blood & cancer》2020,67(5)
58.
Mohamed M Soliman Debkumar Sarkar Ilya Glezerman Majid Maybody 《World Journal of Nephrology》2020,9(2):33-42
BACKGROUNDContrast-induced nephropathy (CIN) is a reversible form of acute kidney injury that occurs within 48-72 h of exposure to intravascular contrast material. CIN is the third leading cause of hospital-acquired acute kidney injury and accounts for 12% of such cases. Risk factors for CIN development can be divided into patient- and procedure-related. The former includes pre-existing chronic renal insufficiency and diabetes mellitus. The latter includes high contrast volume and repeated exposure over 72 h. The incidence of CIN is relatively low (up to 5%) in patients with intact renal function. However, in patients with known chronic renal insufficiency, the incidence can reach up to 27%.AIMTo examine the association between renal enhancement pattern on non-contrast enhanced computed tomographic (CT) images obtained immediately following hepatic artery embolization with development of CIN.METHODSRetrospective review of all patients who underwent hepatic artery embolization between 01/2010 and 01/2011 (n = 162) was performed. Patients without intraprocedural CT imaging (n = 51), combined embolization/ablation (n = 6) and those with chronic kidney disease (n = 21) were excluded. The study group comprised of 84 patients with 106 procedures. CIN was defined as 25% increase above baseline serum creatinine or absolute increase ≥ 0.5 mg/dL within 72 h post-embolization. Post-embolization CT was reviewed for renal enhancement patterns and presence of renal artery calcifications. The association between non-contrast CT findings and CIN development was examined by Fisher’s Exact Test.RESULTSCIN occurred in 11/106 (10.3%) procedures (Group A, n = 10). The renal enhancement pattern in patients who did not experience CIN (Group B, n = 74 with 95/106 procedures) was late excretory in 93/95 (98%) and early excretory (EE) in 2/95 (2%). However, in Group A, there was a significantly higher rate of EE pattern (6/11, 55%) compared to late excretory pattern (5/11) (P < 0.001). A significantly higher percentage of patients that developed CIN had renal artery calcifications (6/11 vs 20/95, 55% vs 21%, P = 0.02).CONCLUSIONA hyperdense renal parenchyma relative to surrounding skeletal muscle (EE pattern) and presence of renal artery calcifications on immediate post-HAE non-contrast CT images in patients with low risk for CIN are independently associated with CIN development. 相似文献
59.
Grüter Thomas Ott Anthonina Meyer Wolfgang Jarius Sven Kinner Markus Motte Jeremias Pitarokoili Kalliopi Gold Ralf Komorowski Lars Ayzenberg Ilya 《Journal of neurology》2020,267(3):715-720
Journal of Neurology - Therapy of autoimmune diseases of the central and peripheral nervous system with intravenous IgG immunoglobulin (IVIg) is well established. Since IVIg is produced from pooled... 相似文献
60.
Velázquez-Pérez Luis Medrano-Montero Jacqueline Rodríguez-Labrada Roberto Canales-Ochoa Nalia Campins Alí Jandy Carrillo Rodes Frank J Rodríguez Graña Tania Hernández Oliver María O. Aguilera Rodríguez Raul Domínguez Barrios Yennis Torres Vega Reydenis Flores Angulo Lissi Cordero Navarro Noharis Y. Sigler Villanueva Aldo A. Gámez Rodríguez Osiel Sagaró Zambrano Ilya Navas Napóles Nayime Y. García Zacarías Javier Serrano Barrera Orlando R. Ramírez Bautista María B. Estupiñán Rodríguez Annelié Guerra Rondón Leonardo A. Vázquez-Mojena Yaimeé González-Zaldivar Yanetza Almaguer Mederos Luis E. Leyva-Mérida Alejandro 《Cerebellum (London, England)》2020,19(2):252-264
The Cerebellum - The prevalence estimations of hereditary ataxias are biased since most epidemiological studies are confined to isolated geographical regions and few nationwide studies are... 相似文献