全文获取类型
收费全文 | 265956篇 |
免费 | 4762篇 |
国内免费 | 1351篇 |
专业分类
化学 | 151042篇 |
晶体学 | 3549篇 |
力学 | 10214篇 |
综合类 | 47篇 |
数学 | 31054篇 |
物理学 | 76163篇 |
出版年
2021年 | 2369篇 |
2020年 | 2849篇 |
2019年 | 3072篇 |
2018年 | 4337篇 |
2017年 | 4063篇 |
2016年 | 5964篇 |
2015年 | 3955篇 |
2014年 | 5478篇 |
2013年 | 12427篇 |
2012年 | 10517篇 |
2011年 | 12161篇 |
2010年 | 8362篇 |
2009年 | 7869篇 |
2008年 | 11287篇 |
2007年 | 11286篇 |
2006年 | 10390篇 |
2005年 | 9595篇 |
2004年 | 8432篇 |
2003年 | 7448篇 |
2002年 | 7113篇 |
2001年 | 6831篇 |
2000年 | 5467篇 |
1999年 | 4077篇 |
1998年 | 3478篇 |
1997年 | 3480篇 |
1996年 | 3396篇 |
1995年 | 2687篇 |
1994年 | 2830篇 |
1993年 | 2875篇 |
1992年 | 3023篇 |
1991年 | 3021篇 |
1990年 | 2881篇 |
1989年 | 2867篇 |
1988年 | 2736篇 |
1987年 | 2706篇 |
1986年 | 2587篇 |
1985年 | 3404篇 |
1984年 | 3524篇 |
1983年 | 2787篇 |
1982年 | 3133篇 |
1981年 | 3001篇 |
1980年 | 2765篇 |
1979年 | 2956篇 |
1978年 | 3055篇 |
1977年 | 3039篇 |
1976年 | 3064篇 |
1975年 | 2897篇 |
1974年 | 2888篇 |
1973年 | 3029篇 |
1972年 | 1963篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Journal of Thermal Analysis and Calorimetry - In the present study, numerical simulations have been carried out on thermal characteristics and second-law analysis of turbulent Cu–H2O... 相似文献
63.
Identification of metabolites of rupestonic acid in rat urine by liquid chromatography combined with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dongyu Gu Yi Yang Qibin Chen Madina Habasi Jiangyu Zhao Haji Akber Aisa 《Biomedical chromatography : BMC》2015,29(4):595-603
Rupestonic acid, a potential anti‐influenza agent, is an important and characteristic compound in Artemisia rupestris L., a well‐known traditional Uighur medicine for the treatment of colds. In the present study, high‐performance liquid chromatography combined with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry was used to detect and identify the metabolites in rat urine after oral administration of rupestonic acid. A total of 10 metabolites were identified or partially characterized. The structure elucidations of the metabolites were performed by comparing the changes in accurate molecular masses and fragment ions with those of the parent compound. The results showed that the main metabolites of rupestonic acid in rat urine were formed by oxidation, hydrogenation and glucuronidation. A metabolism pathway was proposed for the first time based on the characterized structures. This metabolism study can provide essential information for drug discovery, design and clinical application of rupestonic acid. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
64.
This study is concerned with a new,explicit approach by means of which forms of the large strain elastic potential for multiaxial rubberlike elasticity may be obtained based on data for a single deformation mode.As a departure from usual studies,here for the first time errors may be estimated and rendered minimal for all possible deformation modes and,furthermore,failure behavior may be incorporated.Numerical examples presented are in accurate agreement with Treloar's well-known data. 相似文献
65.
66.
Herrasti P. Mazarío E. Recio Francisco J. 《Journal of Solid State Electrochemistry》2021,25(1):231-236
Journal of Solid State Electrochemistry - In this work, the use of neodymium electrodes as a basis for the immobilization of magnetite nanoparticles has been carried out. The sensitivity and... 相似文献
67.
This study compares the physicochemical properties of six electrolytes comprising of three salts: LiFTFSI, NaFTFSI and KFTFSI in two solvent mixtures, the binary (3EC/7EMC) and the ternary (EC/PC/3DMC). The transport properties (conductivity, viscosity) as a function of temperature and concentration were modeled using the extended Jones-Dole-Kaminsky equation, the Arrhenius model, and the Eyring theory of transition state for activated complexes. Results are discussed in terms of ionicity, solvation shell, and cross-interactions between electrolyte components. The application of the six formulated electrolytes in symmetrical activated carbon (AC)//AC supercapacitors (SCs) was characterized by cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), electrochemical impedance spectroscopy (EIS) and accelerated aging. Results revealed that the geometrical flexibility of the FTFSI anion allows it to access and diffuse easily in AC whereas its counter ions (Li+, Na+ or K+) can remain trapped in porosity. However, this drawback was partially resolved by mixing LiFTFSI and KFTFSI salts in the electrolyte. 相似文献
68.
I. F. Golovnev E. I. Golovneva L. A. Merzhievsky V. M. Fomin V. E. Panin 《Physical Mesomechanics》2015,18(3):179-186
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field. 相似文献
69.
70.