全文获取类型
收费全文 | 2370篇 |
免费 | 130篇 |
国内免费 | 6篇 |
专业分类
化学 | 1700篇 |
晶体学 | 9篇 |
力学 | 75篇 |
数学 | 238篇 |
物理学 | 484篇 |
出版年
2023年 | 25篇 |
2022年 | 42篇 |
2021年 | 63篇 |
2020年 | 85篇 |
2019年 | 70篇 |
2018年 | 32篇 |
2017年 | 22篇 |
2016年 | 95篇 |
2015年 | 92篇 |
2014年 | 99篇 |
2013年 | 113篇 |
2012年 | 159篇 |
2011年 | 196篇 |
2010年 | 108篇 |
2009年 | 102篇 |
2008年 | 125篇 |
2007年 | 155篇 |
2006年 | 114篇 |
2005年 | 108篇 |
2004年 | 88篇 |
2003年 | 63篇 |
2002年 | 57篇 |
2001年 | 41篇 |
2000年 | 45篇 |
1999年 | 21篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 22篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1976年 | 18篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 6篇 |
1970年 | 6篇 |
1933年 | 8篇 |
1926年 | 7篇 |
排序方式: 共有2506条查询结果,搜索用时 10 毫秒
1.
2.
The ability of bottlebrush block copolymers (BBCPs) to self-assemble into ordered large periodic structures could greatly expand the scope of photonic and membrane technologies. In this paper, we describe a two-step synthesis of poly(l-lactide)-b-polystyrene (PLLA-b-PS) BBCPs and their rapid thin-film self-assembly. PLLA chains were grown from exo-5-norbornene-2-methanol via ring-opening polymerization (ROP) of l-lactide to produce norbornene-terminated PLLA. Norbonene-terminated PS was prepared using anionic polymerization followed by a termination reaction with exo-5-norbornene-2-carbonyl chloride. PLLA-b-PS BBCPs were prepared from these two norbornenyl macromonomers by a one-pot sequential ring opening metathesis polymerization (ROMP). PLLA-b-PS BBCPs thin-films exhibited cylindrical and lamellar morphologies depending on the relative block volume fractions, with domain sizes of 46–58 nm and periodicities of 70–102 nm. Additionally, nanoporous templates were produced by the selective etching of PLLA blocks from ordered structures. The findings described in this work provide further insight into the controlled synthesis of BBCPs leading to various possible morphologies for applications requiring large periodicities. Moreover, the rapid thin film patterning strategy demonstrated (>5 min) highlights the advantages of using PLLA-b-PS BBCP materials beyond their linear BCP analogues in terms of both dimensions achievable and reduced processing time. 相似文献
3.
4.
We show a faithful restriction theorem among infinite chains which implies a reconstructibility conjecture of Halin. This incite us to study the reconstructibility in the sense of Fraïssé and to prove it for orders of cardinality infinite or ≥ 3 and for multirelations of cardinality infinite or ≥ 7, what improves the theory obtained by G. Lopez in the finite case. For this work we had to study the infinite classes of difference which have to be a linear order of type ω, ω* or ω* + ω; this complete the theory made by G. Lopez for the finite case ([13]). We show also Ulam-reconstructibility for linear orders which have a fixed point. 相似文献
5.
6.
H. V. Klapdor-Kleingrothaus M. Hirsch 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(4):361-372
The physics potential of GENIUS, a recently proposed double beta decay and dark matter experiment is discussed. The experiment will allow to probe neutrino masses down to 10?(2–3) eV. GENIUS will test the structure of the neutrino mass matrix, and therefore implicitly neutrino oscillation parameters comparable or superior in sensitivity to the best proposed dedicated terrestrial neutrino oscillation experiments. If the 10-3 eV level is reached, GENIUS will even allow to test the large angle MSW solution of the solar neutrino problem. Even in its first stage GENIUS will confirm or rule out degenerate or inverted neutrino mass scenarios, which have been widely discussed in the literature as a possible solution to current hints on finite neutrino masses and also test the νe ? νμ hypothesis of the atmospheric neutrino problem. GENIUS would contribute to the search for R-parity violating SUSY and right-handed W-bosons on a scale similar or superior to LHC. In addition, GENIUS would largely improve the current 0νββ decay searches for R-parity conserving SUSY and leptoquarks. Concerning cold dark matter (CDM) search, the low background anticipated for GENIUS would, for the first time ever, allow to cover the complete MSSM neutralino parameter space, making GENIUS competitive to LHC in SUSY discovery. If GENIUS could find SUSY CDM as a by-product it would confirm that R-parity must be conserved exactly. GENIUS will thus be a major tool for future non-accelerator particle physics. 相似文献
7.
Alexopoulos T Allen C Anderson EW Areti H Banerjee S Beery PD Biswas NN Bujak A Carmony DD Carter T Cole P Choi Y De Bonte RJ Erwin AR Findeisen C Goshaw AT Gutay LJ Hirsch AS Hojvat C Kenney VP Lindsey CS LoSecco JM McMahon T McManus AP Morgan N Nelson KS Oh SH Piekarz J Porile NT Reeves D Scharenberg RP Stampke SR Stringfellow BC Thompson MA Turkot F Walker WD Wang CH Wesson DK 《Physical review letters》1990,64(9):991-994
8.
9.
10.