全文获取类型
收费全文 | 1458篇 |
免费 | 31篇 |
国内免费 | 12篇 |
专业分类
化学 | 937篇 |
晶体学 | 19篇 |
力学 | 10篇 |
数学 | 135篇 |
物理学 | 400篇 |
出版年
2021年 | 11篇 |
2020年 | 12篇 |
2019年 | 23篇 |
2018年 | 8篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 16篇 |
2014年 | 32篇 |
2013年 | 66篇 |
2012年 | 75篇 |
2011年 | 95篇 |
2010年 | 38篇 |
2009年 | 48篇 |
2008年 | 82篇 |
2007年 | 83篇 |
2006年 | 86篇 |
2005年 | 88篇 |
2004年 | 84篇 |
2003年 | 68篇 |
2002年 | 52篇 |
2001年 | 38篇 |
2000年 | 32篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 21篇 |
1996年 | 24篇 |
1995年 | 9篇 |
1994年 | 16篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 23篇 |
1984年 | 26篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1976年 | 8篇 |
1975年 | 16篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1968年 | 4篇 |
排序方式: 共有1501条查询结果,搜索用时 31 毫秒
141.
Vossen A Seidl R Adachi I Aihara H Aushev T Balagura V Bartel W Bischofberger M Bondar A Bračko M Browder TE Chang MC Chen A Chen P Cheon BG Cho K Choi Y Eidelman S Feindt M Gaur V Gabyshev N Garmash A Golob B Perdekamp MG Haba J Hayasaka K Horii Y Hoshi Y Hou WS Hyun HJ Inami K Ishikawa A Iwabuchi M Iwasaki Y Iwashita T Joshi NJ Kichimi H Kim HO Kim MJ Ko BR Kumita T Lange JS Lee MJ Lee SH Leitgab M Li Y Liu C Liventsev D Louvot R McOnie S Miyata H Miyazaki Y Mizuk R Mohanty GB Nakano E 《Physical review letters》2011,107(7):072004
The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. 相似文献
142.
Masai H Fujiwara T Matsumoto S Takahashi Y Iwasaki K Tokuda Y Yoko T 《Optics letters》2011,36(15):2868-2870
The authors have demonstrated white light emission of rare earth (RE)-free Mn-doped SnO-ZnO-P(2)O(5) glass. The RE-free glass shows white light emission with a high value of quantum efficiency (QE) comparable to conventional crystalline phosphor. It is notable that the high QE value is attained for RE-free transparent glass, and the broad emission can be continuously tuned by both the amount of activator and the composition of the glass. Since this glass possesses low-melting property, we emphasize that the glass phosphor will lead to the development of a novel inorganic white-light-emitting device in combination with a solid state UV light-emitting source. 相似文献
143.
C. Curceanu M. Bazzi G. Beer L. Bombelli A. M. Bragadireanu M. Cargnelli G. Corradi A. d??Uffizi C. Fiorini T. Frizzi F. Ghio B. Girolami C. Guaraldo R. S. Hayano M. Iliescu T. Ishiwatari M. Iwasaki P. Kienle P. Levi Sandri A. Longoni V. Lucherini J. Marton S. Okada D. Pietreanu K. Piscicchia M. Poli Lener T. Ponta A. Rizzo A. Romero Vidal A. Scordo H. Shi D. L. Sirghi F. Sirghi H. Tatsuno A. Tudorache V. Tudorache O. Vazquez Doce E. Widmann J. Zmeskal 《Few-Body Systems》2011,50(1-4):447-449
The DA??NE electron?Cpositron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons ??beam??. The SIDDHARTA experiment used this beam to perform unprecedented precision measurements on kaonic atoms, while the AMADEUS experiment plans to perform in the coming years precision measurements on kaon?Cnuclei interactions at low-energies, in particular to study the kaonic nuclei. The two experiments are briefly presented in this paper. 相似文献
144.
145.
146.
147.
148.
Tetsushi Kijima Masakazu Nishida Haruhiko Fukaya Masato Yoshida Hideo Sawada 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2555-2564
A reddish‐brown fluoroalkyl end‐capped 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) oligomer/acetone composite was prepared by heating the white oligomer powder with acetone at 80 °C for 3 h. The color was not observed in the corresponding non‐fluorinated AMPS oligomer/acetone composite, which was prepared under similar conditions. The coloring was probably caused by the formation of acetone polyaldol condensation products in the fluorinated oligomeric gel network cores. The colored RF‐(AMPS)n‐RF/acetone composite powders were stable and did not exhibit any color change after 2 years in natural light at room temperature. The colored composite powders dissolved in methanol to give a reddish‐brown solution at room temperature. However, the retro‐polyaldol condensation decolored the solution after 1 day at room temperature. This is the first example of the retro‐aldol polycondensation of acetone under mild conditions. The decoloration increased by between 38‐ and 70‐fold under UV irradiation, compared with that in dark conditions. The coloring–decoloring behavior was consistent and repeatable; therefore our fluorinated oligomer/acetone composites are promising candidates for new fluorinated coloring materials. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2555–2564 相似文献
149.
Chisato Katahira Nobuya Morishita Jun‐Ichi Ikeda Pang Boey Lim Mitsuteru Inoue Yuri Iwasaki Hiroyuki Aota Akira Matsumoto 《Journal of polymer science. Part A, Polymer chemistry》2010,48(20):4445-4455
Our previous mechanistic discussion of the free‐radical crosslinking monoallyl/diallyl copolymerizations was extended to the cationic crosslinking monoepoxide/diepoxide copolymerizations, typically including 1,2‐epoxycyclohexane (ECH) as a monoepoxide and bis[3,4‐epoxycyclohexylmethyl] adipate (BECHMA) as a diepoxide crosslinker. In the cationic polymerization, oligomer is usually obtained because of the occurrence of characteristic chain‐forming reactions. Therefore, cationic crosslinking monoepoxide/diepoxide copolymerizations could be in the category of the network formation through free‐radical crosslinking monoallyl/diallyl copolymerizations. Thus, the gelation behavior was discussed by comparing the actual gel points with the theoretical ones; the greatly delayed gelation from theory was observed. Then, the resulting network polymer precursors (NPPs) were characterized by SEC‐MALLS‐viscometry to clarify the cationic crosslinking ECH/BECHMA copolymerization mechanism. Notably, the correlation lines of molecular weight versus elution volume were specific for the NPPs obtained at a high conversion close to the gel point as compared with those obtained by the free‐radical crosslinking monoallyl/diallyl copolymerization. This may be ascribed to the occurrence of intramolecular and intermolecular chain transfer reactions characteristic of cationic polymerization; the chain transfer reactions involve the intramolecular and intermolecular nucleophilic attack of ether oxygen or terminal hydroxyl oxygen in the NPPs to a terminal growing cation that leads to the formation of not only the loop‐ but also the crosslink‐structures containing NPPs, providing fragile ultrahigh‐molecular‐weight NPP in the SEC columns. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
150.
Yusuke Iwasaki Masato Goto Keisuke Mochizuki Emi Terayama Rie Ito Koichi Saito Norihiro Sugino Tsunehisa Makino Hiroyuki Nakazawa 《Biomedical chromatography : BMC》2011,25(4):503-510
A selective and sensitive HILIC‐MS/MS method for the simultaneous quantification of nicotine and its metabolites in human maternal and cord sera was developed and validated. After solid‐phase extraction, LC separation was achieved on a hydrophilic interaction chromatography. The validated method is capable of selective identification as well as accurate and sensitive quantification. Analyte recovery ranged from 86.2 to 107.7% and intra‐ and inter‐day assay precision were less than 15% relative standard deviation. This sensitive HILIC‐MS/MS method can be used to determine nicotine and its metabolic profile in smokers. This validated method is useful for the determination of nicotine and its metabolites in human serum in future studies of the effects of nicotine exposure on neonatal outcome. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献