全文获取类型
收费全文 | 1889篇 |
免费 | 113篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 38篇 |
妇产科学 | 48篇 |
基础医学 | 352篇 |
口腔科学 | 17篇 |
临床医学 | 199篇 |
内科学 | 487篇 |
皮肤病学 | 24篇 |
神经病学 | 208篇 |
特种医学 | 47篇 |
外科学 | 190篇 |
综合类 | 6篇 |
一般理论 | 1篇 |
预防医学 | 103篇 |
眼科学 | 21篇 |
药学 | 146篇 |
中国医学 | 3篇 |
肿瘤学 | 95篇 |
出版年
2023年 | 16篇 |
2022年 | 57篇 |
2021年 | 108篇 |
2020年 | 29篇 |
2019年 | 54篇 |
2018年 | 49篇 |
2017年 | 33篇 |
2016年 | 50篇 |
2015年 | 61篇 |
2014年 | 83篇 |
2013年 | 70篇 |
2012年 | 126篇 |
2011年 | 133篇 |
2010年 | 81篇 |
2009年 | 61篇 |
2008年 | 129篇 |
2007年 | 118篇 |
2006年 | 116篇 |
2005年 | 105篇 |
2004年 | 89篇 |
2003年 | 85篇 |
2002年 | 83篇 |
2001年 | 26篇 |
2000年 | 19篇 |
1999年 | 12篇 |
1998年 | 14篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1955年 | 3篇 |
排序方式: 共有2017条查询结果,搜索用时 281 毫秒
991.
Skóra Tomasz Nowak-Sadzikowska Jadwiga Mucha-Małecka Anna Szyszka-Charewicz Bogumiła Jakubowicz Jerzy Gliński Bogdan 《European archives of oto-rhino-laryngology》2015,272(3):673-679
European Archives of Oto-Rhino-Laryngology - Approximately 60 % of patients with locally advanced laryngeal cancer (LALC) treated primarily with surgery require adjuvant radiotherapy. In... 相似文献
992.
Role of vascular endothelial growth factor (VEGF) and placenta-derived growth factor (PlGF) in regulating human haemopoietic cell growth 总被引:10,自引:0,他引:10
Mariusz Z. Ratajczak Janina Ratajczak Bogdan Machalinski Marcin Majka Wojtek Marlicz Anna Carter Zbigniew Pietrzkowski & Alan M. Gswirtz 《British journal of haematology》1998,103(4):969-979
Vascular endothelial growth factor (VEGF) and placental derived growth factor (PlGF) stimulate cell proliferation and differentiation by binding to their specific receptors, Flk-1/KDR and Flt-1 respectively. Flk-1/KDR-deficient murine embryos manifest failure of blood-island formation and vasculogenesis. The aim of this study was to directly evaluate the importance of VEGF, PlGF/Flt-1 and Flk-1/KDR receptor ligand interactions in regulating normal and malignant human haemopoiesis. Addition of VEGF and PlGF failed to enhance survival or cloning efficiency of human haemopoietic progenitors isolated from adult bone marrows, fetal livers or cord blood samples. This finding may be explained by the apparent absence of mRNA encoding Flt-1 and Flk-1/KDR receptors on stem cell rich CD34+ c-kit-R+ Rh123low cells. Further studies revealed that Flt-1 R mRNA, but not Flk-1/KDR mRNA was first detectable in the more mature cells isolated from haemopoietic colonies. Accordingly, VEGF receptors are either absent, or expressed at very low level, on human haemopoietic stem/progenitor cells. Of interest, normal and malignant human haemopoietic cells appeared to secrete VEGF protein. However, in contrast to normal haemopoietic progenitors, VEGF co-stimulated HEL cell proliferation as well as CFU-GM colony formation from ∼15% of the chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML) patients studied. Therefore, although VEGF appeared to have minimal effects on normal haemopoietic cell growth it would appear to drive malignant haemopoietic cell proliferation to some degree. Of more importance, however, we speculate that VEGF may play an very important role in leukaemogenesis by stimulating growth of vascular endothelium, thereby providing a sufficient blood supply to feed the growing haematological tumour. 相似文献
993.
Manel Mata-Cases Josep Franch-Nadal Jordi Real Bogdan Vlacho Antón Gómez-García Dídac Mauricio 《Primary Care Diabetes》2021,15(3):588-595
AimsTo describe the characteristics and antidiabetic treatment among type 2 diabetes patients according to the clinical conditions prioritized in the Spanish 2020 RedGDPS (Primary Care Diabetes Study Groups Network) therapeutic algorithm: obesity, older than 75 years, chronic kidney disease, cardiovascular disease, and heart failure.MethodsRetrospective, cross-sectional study. Clinical characteristics, the use of antidiabetic drugs and the KDIGO renal risk categories at 31.12.2016 were retrieved from the SIDIAP (Information System for Research in Primary Care) database (Catalonia, Spain).ResultsFrom a total of 373,185 type 2 diabetes patients, 37% were older than 75 years, 45% obese, 33% had chronic kidney disease, 23.2% cardiovascular disease and 6.9% heart failure. Insulin was more frequently prescribed in chronic kidney disease, cardiovascular disease and heart failure whereas Sodium-Glucose cotransporter 2 inhibitors and Glucagon Like Peptide 1 receptor agonists were scarcely prescribed (2.6% and 1.4%, respectively). Among patients with severe renal failure, contraindicated drugs like metformin (16%) and sulfonylureas (6.1%) were still in use. The 2012 KDIGO renal risk categories distribution was: Low: 60.9%, Moderate: 21.6%, High: 9.8% and Very high: 7.7%.ConclusionsAlmost 80% of our T2DM patients meet one of the five clinical conditions that should be considered for treatment individualization. Importantly, a relevant number of patients with severe renal failure were found to use contraindicated drugs. 相似文献
994.
Vladimir V. Popov Maria Luisa Grilli Andrey Koptyug Lucyna Jaworska Alexander Katz-Demyanetz Damjan Klob
ar Sebastian Balos Bogdan O. Postolnyi Saurav Goel 《Materials》2021,14(4)
The term “critical raw materials” (CRMs) refers to various metals and nonmetals that are crucial to Europe’s economic progress. Modern technologies enabling effective use and recyclability of CRMs are in critical demand for the EU industries. The use of CRMs, especially in the fields of biomedicine, aerospace, electric vehicles, and energy applications, is almost irreplaceable. Additive manufacturing (also referred to as 3D printing) is one of the key enabling technologies in the field of manufacturing which underpins the Fourth Industrial Revolution. 3D printing not only suppresses waste but also provides an efficient buy-to-fly ratio and possesses the potential to entirely change supply and distribution chains, significantly reducing costs and revolutionizing all logistics. This review provides comprehensive new insights into CRM-containing materials processed by modern additive manufacturing techniques and outlines the potential for increasing the efficiency of CRMs utilization and reducing the dependence on CRMs through wider industrial incorporation of AM and specifics of powder bed AM methods making them prime candidates for such developments. 相似文献
995.
Oana Gherasim Roxana Cristina Popescu Valentina Grumezescu George Dan Mogoanu Laureniu Mogoant Florin Iordache Alina Maria Holban Bogdan tefan Vasile Alexandra Ctlina Bîrc Ovidiu-Cristian Oprea Alexandru Mihai Grumezescu Ecaterina Andronescu 《Materials》2021,14(7)
The present study reports on the development and evaluation of nanostructured composite coatings of polylactic acid (PLA) embedded with iron oxide nanoparticles (Fe3O4) modified with Eucalyptus (Eucalyptus globulus) essential oil. The co-precipitation method was employed to synthesize the magnetite particles conjugated with Eucalyptus natural antibiotic (Fe3O4@EG), while their composition and microstructure were investigated using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The matrix-assisted pulsed laser evaporation (MAPLE) technique was further employed to obtain PLA/Fe3O4@EG thin films. Optimal experimental conditions for laser processing were established by complementary infrared microscopy (IRM) and scanning electron microscopy (SEM) investigations. The in vitro biocompatibility with eukaryote cells was proven using mesenchymal stem cells, while the anti-biofilm efficiency of composite PLA/Fe3O4@EG coatings was assessed against Gram-negative and Gram-positive pathogens. 相似文献
996.
The experimental and numerical analyses of the pressure vessels with different flat ends are presented and discussed in the paper. The main aim of the study is to propose the optimal flat head end geometry. The analyses are focused on the comparison of standardized geometries and with the proposed elliptical cut-out. The experimental tests with the application of strain-gauge measurements and numerical modeling of the pressure vessel are conducted. The behavior under low and high pressures and the influence of the residual welding stresses, material properties, and geometrical tolerances on the level of the plastic deformation in the flat end is discussed. It is presented that the rules given in the recent standard are not sufficient for optimal selection of the optimal geometry. It is observed that in certain geometries the deviations of the pipe thickness may lead to a significant increase of the equivalent stresses. The residual welding stresses have a significant influence on the stress and strain level—particularly in the stress relief groove (SRG). The performed study and comparison of the different geometries allow for the proposal of the optimal shape of the flat end. It appeared that the pressure vessels with SRG are the most optimal choice, particularly when elliptic shapes are in use. In some cases (i.e., pipe with wall-thickness equal to 40 mm and the flat end with circular SRG), the optimal configuration is reached for dimensions beyond the admissible by code range. 相似文献
997.
Anna A. Ivanova Dina S. Syromotina Svetlana
N. Shkarina Roman Shkarin Angelica Cecilia Venera Weinhardt Tilo Baumbach Mariia S. Saveleva Dmitry A. Gorin Timothy E. L. Douglas Bogdan V. Parakhonskiy Andre G. Skirtach Pieter Cools Nathalie De Geyter Rino Morent C. Oehr Maria A. Surmeneva Roman A. Surmenev 《RSC advances》2018,8(68):39106
This article reports on a study of the mineralisation behaviour of CaCO3 deposited on electrospun poly(ε-caprolactone) (PCL) scaffolds preliminarily treated with low-temperature plasma. This work was aimed at developing an approach that improves the wettability and permeability of PCL scaffolds in order to obtain a superior composite coated with highly porous CaCO3, which is a prerequisite for biomedical scaffolds used for drug delivery. Since PCL is a synthetic polymer that lacks functional groups, plasma processing of PCL scaffolds in O2, NH3, and Ar atmospheres enables introduction of highly reactive chemical groups, which influence the interaction between organic and inorganic phases and govern the nucleation, crystal growth, particle morphology, and phase composition of the CaCO3 coating. Our studies showed that the plasma treatment induced the formation of O- and N-containing polar functional groups on the scaffold surface, which caused an increase in the PCL surface hydrophilicity. Mineralisation of the PCL scaffolds was performed by inducing precipitation of CaCO3 particles on the surface of polymer fibres from a mixture of CaCl2- and Na2CO3-saturated solutions. The presence of highly porous vaterite and nonporous calcite crystal phases in the obtained coating was established. Our findings confirmed that preferential growth of the vaterite phase occurred in the O2-plasma-treated PCL scaffold and that the coating formed on this scaffold was smoother and more homogenous than those formed on the untreated PCL scaffold and the Ar- and NH3-plasma-treated PCL scaffolds. A more detailed three-dimensional assessment of the penetration depth of CaCO3 into the PCL scaffold was performed by high-resolution micro-computed tomography. The assessment revealed that O2-plasma treatment of the PCL scaffold caused CaCO3 to nucleate and precipitate much deeper inside the porous structure. From our findings, we conclude that O2-plasma treatment is preferable for PCL scaffold surface modification from the viewpoint of use of the PCL/CaCO3 composite as a drug delivery platform for tissue engineering.This article reports on a study of the mineralisation behaviour of CaCO3 deposited on electrospun poly(ε-caprolactone) (PCL) scaffolds preliminarily treated with low-temperature plasma. 相似文献
998.
In vitro study of biocompatibility of a graphene composite with gold nanoparticles and hydroxyapatite on human osteoblasts
下载免费PDF全文
![点击此处可从《Journal of applied toxicology : JAT》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Liana Crisan Bogdan Crisan Olga Soritau Mihaela Baciut Alexandru Radu Biris Grigore Baciut Ondine Lucaciu 《Journal of applied toxicology : JAT》2015,35(10):1200-1210
The purpose of this study was to evaluate the biocompatibility of some composites consisting of different proportions of graphene in combination with gold nanoparticles (AuNPs) and nanostructured hydroxyapatite (HA) on osteoblast viability, proliferation and differentiation. Au/HA@graphene composites synthesized by the catalytic chemical vapor deposition induction heating method with acetylene as the carbon source and over an Au/HA catalyst, were characterized by transmission electron microscopy, thermogravimetric analysis and Raman spectroscopy and showed that the few‐layer graphene was grown over the Au/HA catalyst. The cytocompatibility study was performed using the fluorescein diacetate assay for assessment of the viability and proliferation of osteoblasts cultivated in the presence of HA, Au/HA and Au/HA@graphene composites as colloidal suspensions or as substrates. The most favorable composites for cell adhesion and proliferation were HA, Au/HA and Au/HA composites with 1.6% and 3.15% concentration of graphenes. Immunocytochemical staining performed after 19 days of osteoblasts cultivation on substrates showed that the graphene composites induced low expression of alkaline phosphatase compared to the control group and HA and Au/HA substrates. The presence of graphene in the substrate composition also induced an increased level of intracellular osteopontin and cytoskeleton reorganization (actin‐F) depending on graphene concentration, suggesting cell activation, increased cellular adhesion and acquisition of a mechanosensorial osteocyte phenotype. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
1000.