全文获取类型
收费全文 | 533篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
化学 | 300篇 |
晶体学 | 1篇 |
力学 | 11篇 |
数学 | 124篇 |
物理学 | 113篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 24篇 |
2014年 | 13篇 |
2013年 | 37篇 |
2012年 | 31篇 |
2011年 | 38篇 |
2010年 | 12篇 |
2009年 | 21篇 |
2008年 | 16篇 |
2007年 | 32篇 |
2006年 | 35篇 |
2005年 | 30篇 |
2004年 | 27篇 |
2003年 | 25篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1969年 | 2篇 |
1906年 | 1篇 |
排序方式: 共有549条查询结果,搜索用时 218 毫秒
71.
Sum frequency generation surface vibrational spectroscopy and kinetic measurements using gas chromatography have been used to identify a reactive surface intermediate in situ during hydrogenation of benzene on a Pt(111) single crystal surface at Torr pressures. Upon adsorption at 310 K, both chemisorbed and physisorbed benzene coexist on the surface, a result which has not previously been observed. Kinetic measurements show a linear compensation effect for the production of both cyclohexane and cyclohexene. From these data the isokinetic temperature was identified and correlated to the chemisorbed benzene species, which were probed by means of vibrational spectroscopy. Additionally, chemisorbed benzene was determined to be a reactive intermediate, which is critical for hydrogenation. 相似文献
72.
Abu-Much R Meridor U Frydman A Gedanken A 《The journal of physical chemistry. B》2006,110(16):8194-8203
In this paper, we report on the self-assembly formation of three-dimensional microstructures of Fe3O4 hydrosol. First, we perform new, facile, and direct fabrication of a stable hydrosol of Fe3O4 nanoparticles, based on the sonolysis of an aqueous solution of iron acetate in the presence of PVA-100,000. This is then followed by investigations of the formation of different microstructures obtained on drying a drop of the water suspension on a glass microscope substrate. The evaporation was carried out both without and in the presence of an external magnetic field. 相似文献
73.
In this paper we consider nonlinear boundary value problems whose simplest model is the following:
(0.1) 相似文献
74.
75.
Lucio Centrone 《代数通讯》2013,41(8):3491-3506
76.
Kemilly M. P. Pinheiro Roger C. Moreira Kariolanda C. A. Rezende Mrcio Talhavini Lucio P. L. Logrado Jos A. F. Baio Marcos R. V. Lanza Wendell K. T. Coltro 《Electrophoresis》2019,40(3):462-468
This study describes the development of an analytical methodology based on the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C4D) for the separation and detection of inorganic anions in post‐blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol/L lactic acid, 10 mmol/L histidine and 0.070 mmol/L cetyl(trimethyl ammonium) bromide. For C4D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 Vpp. The separation of Cl?, NO3?, NO2?, SO42?, ClO4? and ClO3? was performed within ca. 150 s with baseline resolution and efficiencies between 4.4 × 104 and 1.7 × 105 plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol/L. Last, real samples of post‐blast explosive residues were analyzed on the ME‐C4D devices obtaining successfully the determination of Cl?, NO3? and SO42?. The achieved concentration values varied between 12.8–72.5 mg/L for Cl?, 1.7–293.1 mg/L for NO3? and 1.3–201.3 mg/L for SO42?. The data obtained using ME‐C4D devices were in good agreement with the concentrations found by ion chromatography. The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the ME‐C4D devices emerge as a powerful and portable analytical platform for on‐site analysis demonstrating to be a promising tool for the crime scene investigation. 相似文献
77.
78.
Neutrino beams obtained from proton accelerators were first operated in 1962. Since then, neutrino beams have been intensively used in particle physics and evolved in many different ways. We describe the characteristics of various neutrino beams, relating them to the historical development of the physics studies and discoveries. We also discuss some of the ideas still under consideration for future neutrino beams.
相似文献79.
80.
The helicoid and plane are the only known complete embedded minimal surfaces inR
3 that are simply connected. We prove the helicoid and plane are the only surfaces of this type that have bounded curvature
and meet each plane x3 = constant in (at most) one smooth connected curve. 相似文献