全文获取类型
收费全文 | 687篇 |
免费 | 6篇 |
国内免费 | 9篇 |
专业分类
化学 | 211篇 |
晶体学 | 2篇 |
力学 | 16篇 |
数学 | 302篇 |
物理学 | 171篇 |
出版年
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 33篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 24篇 |
2007年 | 32篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 24篇 |
2003年 | 21篇 |
2002年 | 21篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 20篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 16篇 |
1984年 | 17篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 9篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 12篇 |
1974年 | 9篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有702条查询结果,搜索用时 15 毫秒
91.
Moshe Gitterman 《Journal of statistical physics》1996,83(5-6):1261-1262
92.
Paul Michael Tessler Moshe Friedman Moshe Halfon Shlomi Palchan Tala Weissman Leonid Arenshtam Alexander Berkovits Dan Eisen Yosef Eliahu Ilan Feinberg Gitai Kijel Daniel Kreisel Arik Mardor Israel Shimel Guy Shor Asher Silverman Ido 《The European Physical Journal A - Hadrons and Nuclei》2019,55(3):1-10
The European Physical Journal A - An empirical formula is proposed for the two-proton decay half-lives. This study is an extension of the empirical formula reported recently by us for calculating... 相似文献
93.
94.
In this paper we study inclusion relations between the following four classes of matrices: normal matrices, matrices with equal spectral radius and spectral norm, matrices whose numerical range coincides with the convex polygon spanned by their eigenvalues, and matrices with equal numerical and spectral radii. 相似文献
95.
96.
As a whole new range of energies will be soon experimentally studied, we present predictions for hadronic cross sections at future very high energy accelerators. All calculations are based on results accumulated in reggeon field theory, where methods of field theory (in the continuum and on the lattice) and statistical mechanics have been used. We have employed these results and translated them into a manageable phenomenological analysis of existing FERMILAB-ISR data. The size of the non-leading terms is determined and enables us to predict cross sections at energies in the range of the near futurep¯p collider. Parameter-free scaling functions and critical exponents which are exactly calculable in RFT are thus brought to an experimental test. 相似文献
97.
Ring structures in telecommunications are taking on increasing importance because of their self-healing properties. We consider a ring design problem in which several stacked self-healing rings (SHRs) follow the same route, and, thus, pass through the same set of nodes. Traffic can be exchanged among these stacked rings at a designated hub node. Each non-hub node may be connected to multiple rings. It is necessary to determine to which rings each node should be connected, and how traffic should be routed on the rings. The objective is to optimize the tradeoff between the costs for connecting nodes to rings and the costs for routing demand on multiple rings. We describe a genetic algorithm that finds heuristic solutions for this problem. The initial generation of solutions includes randomly-generated solutions, complemented by seed solutions obtained by applying a greedy randomized adaptive search procedure (GRASP) to two related problems. Subsequent generations are created by recombining pairs of parent solutions. Computational experiments compare the genetic algorithm with a commercial integer programming package. 相似文献
98.
Acylation through Ketene Intermediates 总被引:1,自引:0,他引:1
Carboxylic acids possessing a strong electron-withdrawing group in the alpha-position undergo facile dehydration upon reaction with carbodiimides to form the corresponding substituted ketenes that can react in situ with alcohols providing esters in a high yield. The ketene formed by the treatment of ethyl 2-methylmalonate with DCC was trapped in situ by a [4+2] cycloaddition with a second DCC molecule. The chemoselectivity of the acylation through the ketene intermediates was found to be substantially different from that of conventional acylation reagents showing a very low sensitivity toward the steric bulk of alcohols. A comparison of the sensitivity of the acylation to the steric bulk of alcohols supports the presence of a pseudopericyclic pathway for the nucleophilic addition of alcohols to ketenes derived from ethyl malonic and diethylphosphonoacetic acid. 相似文献
99.
100.
Koranit Shlosman Ran Y. Suckeveriene Jasmine Rosen‐Kligvasser Roza Tchoudakov Evgeni Zelikman Raphael Semiat Moshe Narkis 《先进技术聚合物》2014,25(12):1484-1491
This paper summarizes a study of controlled migration of an antifog (AF) additive; sorbitan monooleate (SMO), from linear low density polyethylene (LLDPE) films containing a compatibilizer, LLDPE grafted maleic anhydride (LLDPE‐g‐MA). LLDPE/LLDPE‐g‐MA/SMO blends were prepared by melt compounding. Bulk and surface properties of compression molded LLDPE films containing SMO and LLDPE‐g‐MA were characterized using Fourier transform infrared spectroscopy and contact angle measurements. Thermal properties were investigated using a thermal gravimetric analyzer. Diffusion coefficient (D) was calculated, and AF properties were characterized using a “hot fog” test. Compression molded films were characterized for their morphology using high‐resolution scanning electron microscopy, and rheological properties were measured using a parallel‐plate rotational rheometer. It was found that the LLDPE/LLDPE‐g‐MA/SMO systems are characterized by a slower SMO migration rate, a lower diffusion coefficient, and lower contact angle values compared with LLDPE/SMO blends. These results are well correlated with results of a hot fog test. Morphological studies revealed a very fine dispersion of SMO in the LLDPE films, when 3 phr LLDPE‐g‐MA was combined with 1 phr SMO. Thermal analysis results show that the incorporation of 3 phr LLDPE‐g‐MA and 1 phr SMO significantly increases the decomposition temperature of the blend at T > 400°C. At high shear rates, the LLDPE blends show that the AF and the compatibilizer have a lubrication effect on LLDPE. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献