全文获取类型
收费全文 | 1285849篇 |
免费 | 31137篇 |
国内免费 | 8591篇 |
专业分类
化学 | 634409篇 |
晶体学 | 13142篇 |
力学 | 74417篇 |
综合类 | 184篇 |
数学 | 237853篇 |
物理学 | 365572篇 |
出版年
2021年 | 12512篇 |
2020年 | 16256篇 |
2019年 | 16418篇 |
2016年 | 27686篇 |
2015年 | 20899篇 |
2014年 | 30819篇 |
2013年 | 74873篇 |
2012年 | 37311篇 |
2011年 | 32865篇 |
2010年 | 36509篇 |
2009年 | 38881篇 |
2008年 | 31637篇 |
2007年 | 26523篇 |
2006年 | 34571篇 |
2005年 | 26144篇 |
2004年 | 27873篇 |
2003年 | 26316篇 |
2002年 | 24535篇 |
2001年 | 26236篇 |
2000年 | 22174篇 |
1999年 | 20030篇 |
1998年 | 18777篇 |
1997年 | 19398篇 |
1996年 | 19197篇 |
1995年 | 18587篇 |
1994年 | 18122篇 |
1993年 | 17569篇 |
1992年 | 17578篇 |
1991年 | 17822篇 |
1990年 | 17121篇 |
1989年 | 17135篇 |
1988年 | 16701篇 |
1987年 | 16706篇 |
1986年 | 15610篇 |
1985年 | 22165篇 |
1984年 | 23402篇 |
1983年 | 19508篇 |
1982年 | 21220篇 |
1981年 | 20454篇 |
1980年 | 19753篇 |
1979年 | 20095篇 |
1978年 | 21375篇 |
1977年 | 21069篇 |
1976年 | 20782篇 |
1975年 | 19491篇 |
1974年 | 19122篇 |
1973年 | 19652篇 |
1972年 | 14153篇 |
1968年 | 12243篇 |
1967年 | 12598篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Jose M. Guisan Gloria Fernandez-Lorente Javier Rocha-Martin Daniel Moreno-Gamero 《Current Opinion in Green and Sustainable Chemistry》2022
Different strategies for the preparation of efficient and robust immobilized biocatalysts are here reviewed. Different physico-chemical approaches are discussed.i.- The stabilization of enzyme by any kind of immobilization on pre-existing porous supports.ii.- The stabilization of enzymes by multipoint covalent attachment on support surfaces.iii.- Additional stabilization of immobilized-stabilized enzyme by physical or chemical modification with polymers.These three strategies can be easily developed when enzymes are immobilized in pre-existing porous supports. In addition to that, these immobilized-stabilized derivatives are optimal to develop enzyme reaction engineering and reactor engineering. Stabilizations ranging between 1000 and 100,000 folds regarding diluted soluble enzymes are here reported. 相似文献
2.
采用磁控溅射法在ITO玻璃上制备了CdZnTe薄膜,探究机械磨抛对CdZnTe薄膜阻变特性的影响。通过对XRD图谱、Raman光谱、AFM显微照片等实验结果分析阐明了机械磨抛影响CdZnTe薄膜阻变特性的物理机制。研究结果表明,磁控溅射制备的薄膜为闪锌矿结构,F43m空间群。机械磨抛提高了CdZnTe薄膜的结晶质量;CdZnTe薄膜粗糙度(Ra)由磨抛前的3.42 nm下降至磨抛后的1.73 nm;磨抛后CdZnTe薄膜透过率和162 cm-1处的类CdTe声子峰振动峰增强;CdZnTe薄膜的阻变开关比由磨抛前的1.2增加到磨抛后的4.9。机械磨抛提高CdZnTe薄膜质量及阻变特性的原因可能是CdZnTe薄膜在磨抛过程中发生了再结晶。 相似文献
3.
Reutova O. V. Belokoneva E. L. Dimitrova O. V. Volkov A. S. 《Crystallography Reports》2022,67(7):1122-1126
Crystallography Reports - Fluoride crystals K2(Ta0.9I0.1)F7 (sp. gr. Р21/c) complementary to the K2TaF7 and K2NbF7 fluoride family have been obtained by hydrothermal synthesis. Their... 相似文献
4.
Fluid Dynamics - The problem of stability of a subsonic boundary layer is solved under the conditions of heat supply inside the boundary layer with injection of a homogeneous gas through a porous... 相似文献
5.
Nonlinear Dynamics - In this paper, an economic competition between two firms that want to maximize the weighted-average social welfare and own profits is proposed. This kind of competition is... 相似文献
6.
Crystallography Reports - The review presents the important unique results of the cycle of research led by M.V. Kovalchuk on the fundamental patterns of protein interactions and the protein... 相似文献
7.
Osipov Yu. V. Voznesenskii A. S. 《Journal of Applied Mechanics and Technical Physics》2022,63(2):347-355
Journal of Applied Mechanics and Technical Physics - A method for determining the empirical dependence of the rheological properties of rocks on stresses has been developed and tested in... 相似文献
8.
Journal of Experimental and Theoretical Physics - New data concerning neutrino oscillations as obtained in the T2K and NOvA accelerator neutrino experiments are considered. Both collaborations... 相似文献
9.
Pomogaev V. A. Lee H. J. Goh E. Tchaikovskaya O. N. Kononov A. I. Avramov P. V. 《Russian Physics Journal》2022,64(11):2076-2081
Russian Physics Journal - Theoretical calculations of excited states in the complexes of gold and silver three-atom nanoclusters with carbon quantum nanodots are performed using the M062X... 相似文献
10.
This work demonstrates the analytical applicability of single ion-selective membranes (ISMs) and potentiometric sensor array to distinguish and detect cathinone derivatives. Potentiometric data from ISMs based on cation exchanger and varying content of calix[4]arene derivative were processed by principal component analysis (PCA). Such a combination of methods allowed discriminating various individual synthetic cathinones and their recognition from the mixture comprising primary amines (substituted amphetamines+aminoindane). Analytical parameters of ISM containing 1wt % of calix[4]arene derivative were sufficient to detect 1.0×10−4 mol.l−1 1-(4-fluorophenyl)-2-(ethylamino)butan-1-one and 2-(methylamino)-1-phenylbutan-1-one (buphedrone) in both model and saliva samples. 相似文献