全文获取类型
收费全文 | 917篇 |
免费 | 20篇 |
国内免费 | 10篇 |
专业分类
化学 | 571篇 |
晶体学 | 6篇 |
力学 | 7篇 |
数学 | 57篇 |
物理学 | 306篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 4篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 30篇 |
2012年 | 50篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 41篇 |
2008年 | 40篇 |
2007年 | 40篇 |
2006年 | 43篇 |
2005年 | 43篇 |
2004年 | 37篇 |
2003年 | 33篇 |
2002年 | 41篇 |
2001年 | 27篇 |
2000年 | 43篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 17篇 |
1994年 | 23篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 20篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 7篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1972年 | 13篇 |
排序方式: 共有947条查询结果,搜索用时 15 毫秒
841.
A radiometric study of the kinetics of the displacement reaction between nickel(II) and65Zn-labeled zinc salt of ethylenediaminetetraacetic acid, which was previously used by the authors for the analysis of trace
quantities of nickel, has been carried out under varying conditions of temperature, pH etc. The above reaction was confirmed
to be first order with respect to both Ni2+ and to*ZnEDTA. The overall reaction rate constant, kf, has been shown to be inversely proportional to the concentration of Zn2+ and directly proportional to the concentration of H+. From the dependence of the rate constant on the concentration of Zn2+ and H+ a three-step mechanism is proposed for the above reaction. The values for Ea, ΔH‡, ΔG‡ and ΔS‡ for the overall reaction have been computed from the experimental data. 相似文献
842.
The 2P-2P fine structure transition in the ground (3p5) state of the argon atomic ion. Ar+, has been detected in absorption using a tunable diode laser. The transition was calibrated against water vapour lines and measured to be 1431.644 ± 0.001 cm?1 in 40Ar+ and 3.0 × 10?3 cm?1 (91 MHz) smaller in 36Ar+. 相似文献
843.
Hamilton Emmons Juan M. Rivaud 《The Journal of the Operational Research Society》1979,30(11):1005-1011
A large number of coded items such as bank checks are initially mixed randomly. It is desired to sort them into k categories using a sorting device with m pockets (m < k). Several possible objectives are noted, and a new criterion oriented to the average time until categories are sorted out is analyzed. A simple strategy is shown to minimize the average number of sorting passes that elapse until an item is sorted out. 相似文献
844.
845.
846.
847.
Brendan P. Orner Andrew D. Hamilton 《Journal of inclusion phenomena and macrocyclic chemistry》2001,41(1-4):141-147
The guanidinium group is found in many natural products and has been extensively incorporated into various drug designs as well as artificial receptor structures. In this paper we critically review the various synthetic routes to guanidiniums and describe a novel approach that allows the mild formation of multi-substituted derivatives. 相似文献
848.
J. Hamilton C. J. Isham J. Butterfield 《International Journal of Theoretical Physics》2000,39(6):1413-1436
We extend the topos-theoretic treatment given in previous papers of assigningvalues to quantities in quantum theory, and of related issues such as theKochen–Specker theorem. This extension has two main parts: the use of vonNeumann algebras as a base category and the relation of our generalized valuationsto (i) the assignment to quantities of intervals of real numbers and (ii) the ideaof a subobject of the coarse-graining presheaf. 相似文献
849.
将最近从地瓜中提出来的低分子量紫色酸性磷酸酶(smPAP)基因克隆到GST融合蛋白表达载体pGEX-2T中,在大肠杆菌BL21codon plus中进行表达,用表达的融合蛋白免疫兔子产生多克隆抗体,用抗血清在昆虫细胞中表达的smPAP和地瓜提取液中分离纯化的PAP进行检测,产生了良好的交叉反应。 相似文献
850.
Alastair Hamilton 《Letters in Mathematical Physics》2009,89(2):115-130
In this paper we describe a construction which produces classes in compactifications of the moduli space of curves. This construction
extends a construction of Kontsevich which produces classes in the open moduli space from the initial data of a cyclic A
∞-algebra. The initial data for our construction are what we call a ‘quantum A
∞-algebra’, which arises as a type of deformation of a cyclic A
∞-algebra. The deformation theory for these structures is described explicitly. We construct a family of examples of quantum
A
∞-algebras which extend a family of cyclic A
∞-algebras, introduced by Kontsevich, which are known to produce all the kappa classes using his construction.
相似文献