全文获取类型
收费全文 | 874篇 |
免费 | 14篇 |
国内免费 | 4篇 |
专业分类
化学 | 517篇 |
晶体学 | 12篇 |
力学 | 10篇 |
数学 | 92篇 |
物理学 | 261篇 |
出版年
2021年 | 8篇 |
2019年 | 7篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 31篇 |
2012年 | 39篇 |
2011年 | 38篇 |
2010年 | 21篇 |
2009年 | 17篇 |
2008年 | 25篇 |
2007年 | 32篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 28篇 |
2003年 | 16篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 16篇 |
1998年 | 7篇 |
1997年 | 11篇 |
1996年 | 16篇 |
1995年 | 16篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 25篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1977年 | 13篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 8篇 |
1927年 | 7篇 |
1925年 | 8篇 |
1918年 | 9篇 |
1911年 | 7篇 |
1909年 | 10篇 |
1907年 | 7篇 |
1906年 | 9篇 |
排序方式: 共有892条查询结果,搜索用时 19 毫秒
1.
A. Ray R. Sriravindrarajah J.-P. Guerbois P. S. Thomas S. Border H. N. Ray J. Haggman P. Joyce 《Journal of Thermal Analysis and Calorimetry》2007,88(1):279-283
The use of supplementary cementitious materials (SCM) is a well established practice worldwide in the manufacture of Portland cement (PC)-based construction materials. While utilisation of industrial by-products has been successful, the potential of mining wastes is yet to receive adequate attention in the context of construction materials. In an expanded form perlite, which is a naturally occurring, hydrated volcanic siliceous glass, is an ideal material as a lightweight aggregate for use in a wide range of construction materials including concrete. The mining and processing of the grades of perlite required for the production of lightweight aggregate results in the creation of a fine grained waste which currently has no economic value. This paper reports preliminary data on the utilisation of waste perlite fines as a SCM in calcium silicate-based construction material and discusses the potential of this mining waste to reduce the environmental impact of the production of conventional cement-based construction materials. 相似文献
2.
Almost thirty years ago, Penny G. Estabrooks asked “Where and what are the scalar mesons?” (P. Estabrooks, Phys. Rev. D 19, 2678 (1979)). The first part of her question can now be confidently responded (E. van Beveren et al., Z. Phys. C 30, 615 (1986)). However, with respect to the “What” many puzzles remain unanswered. Scalar and axial-vector mesons form part
of a large family of mesons. Consequently, though it is useful to pay them some extra attention, there is no point in discussing
them as isolated phenomena. The particularity of structures in the scattering of --basically-- pions and kaons with zero angular
momentum is the absence of the centrifugal barrier, which allows us to “see” strong interactions at short distances. Experimentally
observed differences and similarities between scalar and axial-vector mesons on the one hand, and other mesons on the other
hand, are very instructive for further studies. Nowadays, there exists an abundance of theoretical approaches towards the
mesonic spectrum, ranging from confinement models of all kinds, i.e., glueballs, and quark-antiquark, multiquark and hybrid configurations, to models in which only mesonic degrees of freedom
are taken into account. Nature seems to come out somewhere in the middle, neither preferring pure bound states, nor effective
meson-meson physics with only coupling constants and possibly form factors. As a matter of fact, apart from a few exceptions,
like pions and kaons, Nature does not allow us to study mesonic bound states of any kind, which is equivalent to saying that
such states do not really exist. Hence, instead of extrapolating from pions and kaons to the remainder of the meson family,
it is more democratic to consider pions and kaons mesonic resonances that happen to come out below the lowest threshold for
strong decay. Nevertheless, confinement is an important ingredient for understanding the many regularities observed in mesonic
spectra. Therefore, excluding quark degrees of freedom is also not the most obvious way of describing mesons in general, and
scalars and axial-vectors in particular. 相似文献
3.
4.
Stephen L. Howard Joyce E. Newberry Rosario C. Sausa Andrzej W. Miziolek 《Journal of the American Society for Mass Spectrometry》1993,4(2):152-158
A recently developed research apparatus for characterization of low-pressure premixed flames has been developed and was used to characterize the C2H4/N2O/Ar flame at 20 torr. This instrument incorporates several diagnostic techniques in one apparatus so that individual techniques can be quantitatively compared and the usable detection range (both in terms of resolution and species detection) expanded. Results discussed in this report include mass analysis by triple quadrupole mass spectrometer and temperature measurement by thermocouple. Concentration profiles in the one-dimensional flame include CO, N2, and C2H4, at nominal m/z 28 as well as CO2 and N2O at m/z 44. 相似文献
5.
E. Rupp 《Fresenius' Journal of Analytical Chemistry》1925,67(3):119
Ohne Zusammenfassung 相似文献
6.
7.
8.
9.
Kochocki JA Allison WW Alner GJ Ambats I Ayres DS Balka LJ Barr GD Barrett WL Benjamin D Border P Brooks CB Cobb JH Cockerill DJ Coover K Courant H Dahlin B DasGupta U Dawson JW Edwards VW Fields TH Kirby-Gallagher LM Garcia-Garcia C Giles RH Goodman MC Heller K Heppelman S Hill N Hoftiezer JH Jankowski DJ Johns K Joyce T Kafka T Litchfield PJ Lopez FV Lowe M Mann WA Marshak ML May EN McMaster L Milburn RH Miller W Napier A Oliver WP Pearce GF Perkins DH Peterson EA Price LE Roback D Rosen DB 《Physical review D: Particles and fields》1990,42(9):2967-2973
10.
Mathiazhagan C Molzon WR Cousins RD Konigsberg J Kubic J Melese P Rubin P Slater WE Wagner D Hart GW Kinnison WW Lee DM McKee RJ Milner EC Sanders GH Ziock HJ Arisaka K Knibbe P Urheim J Axelrod S Biery KA Irwin GM Lang K Margulies J Ouimette DA Ritchie JL Trang QH Wojcicki SG Auerbach LB Buchholz P Highland VL McFarlane WK Sivertz M Chapman MD Eckhause M Ginkel JF Hancock AD Joyce D Kane JR Kenney CJ Vulcan WF Welsh RE Whyley RJ Winter RG 《Physical review letters》1989,63(20):2181-2184