全文获取类型
收费全文 | 1065篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
化学 | 592篇 |
晶体学 | 5篇 |
力学 | 114篇 |
数学 | 137篇 |
物理学 | 236篇 |
出版年
2023年 | 5篇 |
2022年 | 31篇 |
2021年 | 44篇 |
2020年 | 21篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 27篇 |
2016年 | 33篇 |
2015年 | 30篇 |
2014年 | 50篇 |
2013年 | 92篇 |
2012年 | 49篇 |
2011年 | 81篇 |
2010年 | 51篇 |
2009年 | 34篇 |
2008年 | 59篇 |
2007年 | 39篇 |
2006年 | 33篇 |
2005年 | 31篇 |
2004年 | 35篇 |
2003年 | 18篇 |
2002年 | 21篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1998年 | 11篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1979年 | 6篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 8篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1971年 | 19篇 |
1970年 | 14篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1967年 | 9篇 |
1966年 | 4篇 |
排序方式: 共有1084条查询结果,搜索用时 46 毫秒
31.
32.
Pauling described metallic bonds using resonance. The maximum probability domains in the Kronig–Penney model can show a picture of it. When the walls are opaque (and the band gap is large) the maximum probability domain for an electron pair essentially corresponds to the region between the walls: the electron pairs are localized within two consecutive walls. However, when the walls become transparent (and the band gaps closes), the maximum probability domain can be moved through the system without a significant loss in probability. 相似文献
33.
Mihaela Gulea Isabelle Abrunhosa Jozef Drabowicz Guillaume Grach Matthieu Hamel Serge Masson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1267-1272
Abstract A new method to prepare enantioenriched sulfinates was developed to obtain optically active ortho-methylsulfinyl(phenylphosphonates). It consists of a diastereoselective oxidation of sulfenates to sulfinates. Additionally, preliminary results concerning the synthesis of ortho-phophonylated benzylic thiol derivatives via a new P═S to P═C [1,4]-rearrangement and a first synthetic application of these compounds are also described. 相似文献
34.
35.
Taniya M. S. K. Pathiranage Dushanthi S. Dissanayake Crystal N. Niermann Yixin Ren Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2017,55(20):3327-3346
Semiconducting polythiophenes display electroactive properties which make them excellent candidates for applications as electroactive materials. Ability to undergo doping and to switch between different oxidation states allow tuning the chemical and physical properties of polythiophenes. Furthermore, the ability to integrate polythiophenes into copolymers, hybrid composites with metals and inorganic materials make them useful in electronic and biomedical applications. The capability to vary the properties of the final material with low production cost and high processability into thin films makes polythiophenes desirable materials for many applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3327–3346 相似文献
36.
Flavie Peudru Remi Legay Jean-François Lohier Vincent Reboul Mihaela Gulea 《Tetrahedron》2012,68(44):9016-9022
A new efficient and general synthetic methodology to access γ-aminothiols was investigated and developed. 1,3-Thiazines were used as convenient precursors and were prepared by a fast microwave-assisted three-component reaction (3CR) of thioamides, aldehydes, and alkenes. The transformation of thiazines into aminothiols was achieved via a thiazinium salt hydrolysis, in three very facile steps. 相似文献
37.
The position of a graphene nanoribbon on a solid substrate allows the chemical modification of only one of the nanoribbon sides. A method was proposed that enables the chemical modification of the other side, too. It was numerically modeled how a nanoribbon separated from a substrate rolls up into a roll and how the roll unrolls on a flat substrate. The dependences of the number of coils and the radii of rolls forming by hydrogenation on the nanoribbon length and width were determined. 相似文献
38.
Chelate polymers derived from bis(2,4-dihydroxybenzaldehyde)propyl-enediimine M and bis(2,4-dihydroxyacetophenone)propylenediimine M (M = Fe2+, Co2+, Ni2+, Cu2+, Zn2+) with aromatic acid chlorides were prepared by interfacial polycondensation. Also, chelate polysiloxanes were obtained from the same monomers and α,ω-dichloropolydimethyl-siloxane. The spectral, thermal, magnetic, and electrical properties of the polychelates were studied. 相似文献
39.
Cristina Bucur Romana Cerc Korošec Mihaela Badea Larisa Calu Mariana Carmen Chifiriuc Nicoleta Grecu Nicolae Stanică Dana Marinescu Rodica Olar 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1287-1295
Novel complexes of type M2LCl4·nH2O (M: Ni, n = 4; M: Cu, n = 2.5 and M: Zn, n = 1.5; L: ligand resulted from 1,3-phenylenediamine, 3,6-diazaoctane-1,8-diamine, and formaldehyde one-pot condensation) were synthesized and characterized. The ligand was also isolated and characterized. The complexes features have been assigned from microanalytical, electrospray ionization tandem mass spectrometry, IR, UV–vis, 1H NMR, and EPR spectra as well as magnetic data at room temperature. Simultaneous thermogravimetric/dynamic scanning calorimetry/evolved gas analysis measurements were performed to evidence the nature of the gaseous products formed in each step. Processes as water elimination, fragmentation, and oxidative degradation of the organic ligand as well as chloride elimination were observed during the thermal decomposition. The final product of decomposition was metal(II) oxide except for copper complex where CuCl remained also in the oxide network. The complexes exhibited an improved antibacterial activity in comparison with the ligand concerning both planktonic as well as biofilm-embedded cells. 相似文献
40.
Hermina Iulia Petkes Emese Gál Luiza Găină Mihaela Sabou Cornelia Majdik Luminiţa Silaghi-Dumitrescu 《Comptes Rendus Chimie》2014,17(10):1050-1056
The synthesis of new phenothiazinyl- and phenyl-nitrones under classical versus microwave heating conditions is described. Better yields were obtained under microwave irradiation in the condensation reactions of phenothiazyl-carbaldehyde with hydroxylamine derivatives. The structures of the new phenothiazinyl-nitrones were assigned on the basis of MS, FT–IR and NMR spectra. The new nitrones and some known phenyl-nitrones were screened for their antibacterial and antifungal activity against several Candida species, Gram negative bacteria, such as E. coli, Citrobacter spp, Morganella spp, Pseudomonas aeruginosa, Klebsiella pneumoniae (± ESBL), Proteus spp, Acinetobacter spp and the Gram positive bacterium Staphylococcus aureus, with moderate results. 相似文献