全文获取类型
收费全文 | 2440篇 |
免费 | 56篇 |
国内免费 | 6篇 |
专业分类
化学 | 1876篇 |
晶体学 | 25篇 |
力学 | 46篇 |
数学 | 108篇 |
物理学 | 447篇 |
出版年
2022年 | 19篇 |
2021年 | 19篇 |
2020年 | 31篇 |
2019年 | 34篇 |
2018年 | 29篇 |
2017年 | 15篇 |
2016年 | 46篇 |
2015年 | 39篇 |
2014年 | 45篇 |
2013年 | 90篇 |
2012年 | 105篇 |
2011年 | 111篇 |
2010年 | 74篇 |
2009年 | 83篇 |
2008年 | 137篇 |
2007年 | 96篇 |
2006年 | 135篇 |
2005年 | 136篇 |
2004年 | 108篇 |
2003年 | 94篇 |
2002年 | 74篇 |
2001年 | 51篇 |
2000年 | 60篇 |
1999年 | 38篇 |
1998年 | 26篇 |
1997年 | 37篇 |
1996年 | 35篇 |
1995年 | 21篇 |
1994年 | 39篇 |
1993年 | 26篇 |
1992年 | 42篇 |
1991年 | 22篇 |
1990年 | 29篇 |
1989年 | 28篇 |
1988年 | 28篇 |
1987年 | 41篇 |
1986年 | 28篇 |
1985年 | 35篇 |
1984年 | 34篇 |
1983年 | 27篇 |
1982年 | 37篇 |
1981年 | 37篇 |
1980年 | 38篇 |
1979年 | 35篇 |
1978年 | 24篇 |
1977年 | 33篇 |
1976年 | 26篇 |
1975年 | 19篇 |
1974年 | 15篇 |
1973年 | 15篇 |
排序方式: 共有2502条查询结果,搜索用时 15 毫秒
991.
992.
K Isosaki N Seno I Matsumoto T Koyama S Moriguchi 《Journal of chromatography. A》1992,597(1-2):123-128
Methyl vinyl ether-maleic anhydride copolymer (MMAC) is a water-insoluble polymer with an acid anhydride group which reacts with amino groups of ligands to form stable amide bonds. MMAC was used to immobilize protein ligands on two kinds of supports, the wells of plastic microtitre plates for enzyme-linked immunosorbent assay and related methods, and gels for affinity adsorbents. The wells were first coated with MMAC and then allowed to react with proteins. The immobilization of proteins by this method was efficient and occurred in a dose-dependent manner. Shodex Et123, a gel having amino groups, was incubated with MMAC, and then the activated Shodex was used to immobilize high concentrations of proteins. Concanavalin A-Shodex thus obtained had high affinities and was successfully used for the high-performance liquid affinity chromatography of sugar derivatives on a short column. 相似文献
993.
Furukawa R. Uyama H. Matsumoto O. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(6):930-933
Carburizing and diamond deposition experiments were done on titanium, niobium, and molybdenum substrates with argon-methane-hydrogen gas mixture plasma jets at a pressure of 200 torr for various hydrogen concentrations. Diamond deposition was obtained at a volume of 7% hydrogen added to the plasma jet. The deposits were markedly different on the different metal substrates. Diamond deposits with habit planes were clearly observed on niobium and molybdenum, while the deposit on titanium consisted of ball-like particles. The emission spectra from the plasma jet were the same, for all the substrates, proving that the difference in the diamond deposit depends on the substrate characteristics. CH, C2, hydrogen, and carbon atoms were identified in the plasma jet. The difference in the deposits is attributed to the reactivity of carbon species in the plasma with the metal surface as well as to the solubility of hydrogen in metals 相似文献
994.
In this article, the existence of additive BIB designs is discussed with direct and recursive constructions, together with investigation of a property of resolvability. Such designs can be used to construct infinite families of BIB designs. In particular, we obtain a series of B(sn, tsm, λt (tsm ? 1) (sn‐m ? 1)/[2(sm ? 1)]) for any positive integer λ, such that sn (sn ? 1) λ ≡ 0 (mod sm (sm ? 1) and for any positive integer t with 2 ≤ t ≤ sn‐m, where s is an odd prime power. Connections between additive BIB designs and other combinatorial objects such as multiply nested designs and perpendicular arrays are discussed. A construction of resolvable BIB designs with v = 4k is also proposed. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 235–254, 2007 相似文献
995.
996.
997.
998.
999.
H. Matsumoto J. Rogers H. Umezawa M. Tachiki 《Journal of magnetism and magnetic materials》1980,20(1):11-28
Electron tunneling into ferromagnetic metals is investigated experimentally and theoretically. A large conductance dip centered at the origin is observed for Fe, but for Ni, a smaller dip at the origin appears to be superimposed on a broad peak near the origin. These features may be explained as superimposed elastic and inelastic tunneling effects due to spin waves. 相似文献
1000.
Indium-tin oxides (ITO) films were prepared on glass by Ar ion sputtering, ion plating and electron beam melting in vacuum,
and tin oxide films were prepared by chemical vapour deposition (CVD) of SnCl4 in methanol containing HF. The chemical state of samples prepared was analyzed by CEMS. ITO films, produced from ITO source
materials with higher solubility of tin oxide, showed lower electric resistivity. Amorphous ITO films had larger quadrupole
splitting than crystalline ones. The tin oxide films were exposed in hydrogen plasma and hydrogen gas and the change of these
films was also assessed by CEMS. 相似文献