全文获取类型
收费全文 | 1797篇 |
免费 | 21篇 |
国内免费 | 10篇 |
专业分类
化学 | 983篇 |
晶体学 | 11篇 |
力学 | 62篇 |
数学 | 228篇 |
物理学 | 544篇 |
出版年
2020年 | 15篇 |
2018年 | 13篇 |
2016年 | 14篇 |
2015年 | 18篇 |
2014年 | 22篇 |
2013年 | 88篇 |
2012年 | 81篇 |
2011年 | 87篇 |
2010年 | 56篇 |
2009年 | 23篇 |
2008年 | 53篇 |
2007年 | 78篇 |
2006年 | 54篇 |
2005年 | 59篇 |
2004年 | 61篇 |
2003年 | 56篇 |
2002年 | 57篇 |
2001年 | 36篇 |
2000年 | 52篇 |
1999年 | 31篇 |
1998年 | 22篇 |
1997年 | 26篇 |
1996年 | 38篇 |
1995年 | 31篇 |
1994年 | 33篇 |
1993年 | 37篇 |
1992年 | 32篇 |
1991年 | 36篇 |
1990年 | 27篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 18篇 |
1981年 | 24篇 |
1980年 | 28篇 |
1979年 | 41篇 |
1978年 | 24篇 |
1977年 | 23篇 |
1976年 | 27篇 |
1975年 | 19篇 |
1974年 | 34篇 |
1973年 | 32篇 |
1972年 | 14篇 |
1971年 | 16篇 |
1970年 | 15篇 |
1969年 | 16篇 |
排序方式: 共有1828条查询结果,搜索用时 0 毫秒
151.
152.
Gu P Haas P Hogan WP Kim SK Matthews JN Myung SS Schnetzer S Thomson GB Zou Y Arisaka K Roberts D Slater W Spencer MB Weaver M Briere RA Cheu E Harris DA Krolak P McFarland KS Roodman A Schwingenheuer B Somalwar SV Wah YW Winstein B Winston R Barker AR Swallow EC Bock GJ Coleman R Crisler M Enagonio J Ford R Hsiung YB Jensen DA O'Dell VR Ramberg E Tschirhart R Collins EM Gollin GD Nakaya T Yamanaka T 《Physical review letters》1996,76(23):4312-4315
153.
Asner DM Athanas M Bliss DW Brower WS Masek G Paar HP Gronberg J Korte CM Kutschke R Menary S Morrison RJ Nakanishi S Nelson HN Nelson TK Qiao C Richman JD Roberts D Ryd A Tajima H Witherell MS Balest R Cho K Ford WT Lohner M Park H Rankin P Smith JG Alexander JP Bebek C Berger BE Berkelman K Bloom K Browder TE Cassel DG Cho HA Coffman DM Crowcroft DS Dickson M Drell PS Dumas DJ Ehrlich R Elia R Gaidarev P Garcia-Sciveres M Gittelman B Gray SW Hartill DL Heltsley BK Henderson S Jones CD 《Physical review D: Particles and fields》1996,53(3):1039-1050
154.
S.M Roberts 《Journal of Mathematical Analysis and Applications》1983,97(1):245-265
The analytical and approximate soluions of ?y″ = yy′ are developed and compared, and the analytical solution is evaluated numerically. The analytical soluion has several interesting properties: (i) it possesses three different types of solutions, constant, exponential, and tangent; (ii) for a two-point boundary value problem it has an undecidability aspect relative to which solution type holds; (iii) for the tangent solution type an infinite number of solutions exist, both continuous and discontinuous; (iv) even with the analytical solution known, its numerical evaluation can still be difficult to generate. 相似文献
155.
156.
Marco Rahm David Schurig Daniel A. Roberts Steven A. Cummer David R. Smith John B. Pendry 《Photonics and Nanostructures》2008,6(1):87-VII
The technique of applying form-invariant, spatial coordinate transformations of Maxwell’s equations can facilitate the design of structures with unique electromagnetic or optical functionality. Here, we illustrate the transformation-optical approach in the designs of a square electromagnetic cloak and an omni-directional electromagnetic field concentrator. The transformation equations are described and the functionality of the devices is numerically confirmed by two-dimensional finite element simulations. The two devices presented demonstrate that the transformation optic approach leads to the specification of complex, anisotropic and inhomogeneous materials with well directed and distinct electromagnetic behavior. 相似文献
157.
Surface chemistry of carbon dioxide 总被引:5,自引:0,他引:5
The review discusses how CO2 surface chemistry has developed since the early 1950s. Emphasis is given to studies of well-characterized surfaces of metals, oxides and some more complex systems involving in particular alkali modified surfaces and also of coadsorbed molecules. 相似文献
158.
Measurements are reported of NH exchange rates of urea, thiourea, acetamide and thioacetamide, using line-shape analysis with natural-abundance 15N NMR spectra. Base-catalyzed NH-proton exchange of thiourea is 30–40 times faster than for urea, while the corresponding acid-catalyzed exchange is 150 times slower. The base-catalyzed proton exchange for thioacetamide is about 1000 times faster than that of acetamide at 25°C, while the corresponding acid-catalyzed exchange is some 260 times slower. 相似文献
159.
The relationship between mixture flow parameters and the combustion noise from open turbulent premixed gaseous flames is investigated experimentally and it is shown how the overall noise levels and frequency spectra are related to certain flow and geometric parameters and to the turbulence structure of the combustible mixture. 相似文献
160.
The splitting of trajectories with non-vacuum quantum numbers is discussed within the dual unitarisation scheme. The estimated difference in intercepts between vector-tensor trajectories of opposite signatures, such as ? ? A2 and , agrees both in sign and magnitude with that deduced from phenomenological analyses. 相似文献