全文获取类型
收费全文 | 901篇 |
免费 | 57篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 1篇 |
基础医学 | 222篇 |
口腔科学 | 78篇 |
临床医学 | 26篇 |
内科学 | 240篇 |
皮肤病学 | 7篇 |
神经病学 | 16篇 |
特种医学 | 24篇 |
外科学 | 24篇 |
综合类 | 97篇 |
预防医学 | 27篇 |
眼科学 | 14篇 |
药学 | 152篇 |
中国医学 | 24篇 |
肿瘤学 | 16篇 |
出版年
2023年 | 13篇 |
2022年 | 75篇 |
2021年 | 106篇 |
2020年 | 29篇 |
2019年 | 22篇 |
2018年 | 24篇 |
2017年 | 30篇 |
2016年 | 9篇 |
2015年 | 32篇 |
2014年 | 54篇 |
2013年 | 80篇 |
2012年 | 34篇 |
2011年 | 51篇 |
2010年 | 31篇 |
2009年 | 36篇 |
2008年 | 45篇 |
2007年 | 32篇 |
2006年 | 28篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 23篇 |
2002年 | 21篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
排序方式: 共有972条查询结果,搜索用时 187 毫秒
51.
52.
Junhao Huang Saeed Zajforoushan Moghaddam Esben Thormann 《Macromolecular chemistry and physics.》2020,221(8)
Oxidation of alginate is a promising method that creates aldehyde groups, which can form stable cross‐links with amine groups on chitosan. In this work, it is shown that a systematic variation in the oxidation degree of alginate dialdehyde allows for effective tuning of the swelling capacity of chitosan/alginate dialdehyde multilayer films. Furthermore, it is demonstrated that the pH‐responsiveness of the multilayer films can be regulated by the choice of pH at which the layer‐by‐layer assembly is conducted. The combination of these two parameters allows for the designing polysaccharide multilayer films with a tunable degree of swelling and stimuli‐responsiveness. 相似文献
53.
Fabien Dalonneau Xi Qiu Liu Rabia Sadir Jorge Almodovar Hichem C. Mertani Franz Bruckert Corinne Albiges-Rizo Marianne Weidenhaupt Hugues Lortat-Jacob Catherine Picart 《Biomaterials》2014
Several chemokines are important in muscle myogenesis and in the recruitment of muscle precursors during muscle regeneration. Among these, the SDF-1α chemokine (CXCL12) is a potent chemoattractant known to be involved in muscle repair. SDF-1α was loaded in polyelectrolyte multilayer films made of poly(l-lysine) and hyaluronan to be delivered locally to myoblast cells in a matrix-bound manner. The adsorbed amounts of SDF-1α were tuned over a large range from 100 ng/cm2 to 5 μg/cm2, depending on the initial concentration of SDF-1α in solution, its pH, and on the film crosslinking extent. Matrix-bound SDF-1α induced a striking increase in myoblast spreading, which was revealed when it was delivered from weakly crosslinked films. It also significantly enhanced cell migration in a dose-dependent manner, which again depended on its presentation by the biopolymeric film. The low-crosslinked film was the most efficient in boosting cell migration. Furthermore, matrix-bound SDF-1α also increased the expression of myogenic markers but the fusion index decreased in a dose-dependent manner with the adsorbed amount of SDF-1α. At high adsorbed amounts of SDF-1α, a large number of Troponin T-positive cells had only one nucleus. Overall, this work reveals the importance of the presentation mode of SDF-1α to emphasize its effect on myogenic processes. These films may be further used to provide insight into the role of SDF-1α presented by a biomaterial in physiological or pathological processes. 相似文献
54.
Epitaxial Ni-Mn-Ga thin films have been extensively investigated, due to their potential applications in magnetic micro-electro-mechanical systems. It has been proposed that the martensitic phase in the <1 1 0>A-oriented film is much more stable than that in the <1 0 0>A-oriented film. Nevertheless, the magnetic properties, microstructural features, and crystal structures of martensite in such films have not been fully revealed. In this work, the <1 1 0>A-oriented Ni51.0Mn27.5Ga21.5 films with different thicknesses were prepared by epitaxially growing on Al2O3(1 1 0) substrate by magnetron sputtering. The characterization by X-ray diffraction technique and transmission electron microscopy revealed that all the Ni51.0Mn27.5Ga21.5 films are of 7M martensite at the ambient temperature, with their Type-I and Type-II twinning interfaces nearly parallel to the substrate surface. 相似文献
55.
Fabian Hrtwig Lars Lorenz Stefan Makowski Matthias Krause Carsten Habenicht Andrs Fabin Lasagni 《Materials》2022,15(7)
Vacuum environments provide challenging conditions for tribological systems. MoS2 is one of the materials commonly known to provide low friction for both ambient and vacuum conditions. However, it also exhibits poor wear resistance and low ability to withstand higher contact pressures. In search of wear-resistant alternatives, superhard hydrogen-free tetrahedral amorphous carbon coatings (ta-C) are explored in this study. Although known to have excellent friction and wear properties in ambient atmospheres, their vacuum performance is limited when self-paired and with steel. In this study, the influence of the paired material on the friction behavior of ta-C is studied using counterbodies made from brass, bronze, copper, silicon carbide, and aluminum oxide, as well as from steel and ta-C coatings as reference materials. Brass was found to be the most promising counterbody material and was further tested in direct comparison to steel, as well as in long-term performance experiments. It was shown that the brass/ta-C friction pair exhibits low friction (µ < 0.1) and high wear in the short term, irrespective of ambient pressure, whereas in the long term, the friction coefficient increases due to a change in the wear mechanism. Al2O3 was identified as another promising sliding partner against ta-C, with a higher friction coefficient than that of brass (µ = 0.3), but considerably lower wear. All other pairings exhibited high friction, high wear, or both. 相似文献
56.
Anton S. Voronin Yurii V. Fadeev Mstislav O. Makeev Pavel A. Mikhalev Alexey S. Osipkov Alexander S. Provatorov Dmitriy S. Ryzhenko Gleb Y. Yurkov Mikhail M. Simunin Darina V. Karpova Anna V. Lukyanenko Dieter Kokh Dashi D. Bainov Igor A. Tambasov Sergey V. Nedelin Nikita A. Zolotovsky Stanislav V. Khartov 《Materials》2022,15(4)
Embedded copper mesh coatings with low sheet resistance and high transparency were formed using a low-cost Cu seed mesh obtained with a magnetron sputtering on a cracked template, and subsequent operations electroplating and embedding in a photocurable resin layer. The influence of the mesh size on the optoelectric characteristics and the electromagnetic shielding efficiency in a wide frequency range is considered. In optimizing the coating properties, a shielding efficiency of 49.38 dB at a frequency of 1 GHz, with integral optical transparency in the visible range of 84.3%, was obtained. Embedded Cu meshes have been shown to be highly bending stable and have excellent adhesion strength. The combination of properties and economic costs for the formation of coatings indicates their high prospects for practical use in shielding transparent objects, such as windows and computer monitors. 相似文献
57.
Patrizia Lamberti Monica La Mura Vincenzo Tucci Erick Nkyalu Ali Khan Marina Yakovleva Nadzeya Valynets Alesia Paddubskaya Aleksandr Saushin Viatcheslav Vanyukov Marian Baah Andrzej Urbanowicz Yuri Svirko Polina Kuzhir 《Materials》2022,15(3)
We report the performance of a graphene-enhanced THz grating fabricated by depositing a gold layer on the femtosecond micromachined SiO2 substrate. The morphology of the gold plated patterned substrate was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the quality of the chemical vapor deposition (CVD) graphene was evaluated by Raman spectroscopy. The electromagnetic (EM) response of the metasurface comprising the graphene sheet and the gold plated substrate was studied by THz time domain spectroscopy in the 100 GHz–1 THz frequency range. We employed the finite elements method (FEM) to model the metasurface EM response by adjusting the ac conductivity of the gold layer covering the patterned SiO2 substrate to reproduce the measured transmission/reflection spectra. The results of the numerical simulation reveal the impact of the imperfectness of the gold layer on the performance of the THz metasurface. The experimental results are well described in terms of the Drude–Smith model of metal conductivity that takes into account the anisotropic scattering of the carriers in thin metal films. 相似文献
58.
以无毒氧化葡萄糖醛作交联剂 ,采用溶液共混交联法制备壳聚糖改性丝素合金膜。用 FTIR、DSC表征其结构 ,测定其等电点、力学性能、不同 p H条件下的溶胀率和对模型药物 5 - Fu的渗透性。结果表明 :改性丝素合金膜中丝素和壳聚糖分子间存在着强烈的氢键相互作用及良好的相容性。改性膜的等电点对应的 p H值是 5 .35 ,而丝素膜的等电点是 4 .5。改性膜的力学性能优于单组分膜 ,当壳聚糖含量为 4 0 %~ 6 0 %时 ,具有最大的抗张强度和拉伸率 ,分别为 71.4~ 72 .7MPa和 2 .96~ 3.82 %。改性丝素合金膜对 5 - Fu的渗透量与壳聚糖的含量和时间成正相关关系 ,渗透系数随 p H值增大 (5→ 9)先逐渐减小然后略有增大 ,在 p H=7时最小。 相似文献
59.
60.
Hans H. Strupp 《Contemporary psychoanalysis》2013,49(2):235-251
The portrayal of psychoanalysts in films and on television is usually a far cry from being a realistic depiction. As professional consultant to a TV series, I initially believed that my task was to uphold the public reputation of analysts; but, as I became further involved, I realized that the shortcomings and failures of analysts are essential to good drama. Films do not attempt to represent the actual reality accurately but rather to convey an inner reality. The analyst as protagonist becomes a far more interesting character once we observe him dealing with his conflicts, weaknesses, and limitations. Filmmakers attempt to allow for our authenticity and humanity and permit the analyst to enact well beyond what may be considered acceptable, not because they want to denigrate him but rather to show the fragile human being behind the professional. My role as consultant was to try to assure accuracy in the depiction of the analyst's work and at the same time to allow the drama to reach those dangerous and dark places that our work does not ordinarily traverse but that nevertheless represent our deepest wishes and anxieties. 相似文献