全文获取类型
收费全文 | 458篇 |
免费 | 27篇 |
专业分类
化学 | 411篇 |
晶体学 | 2篇 |
力学 | 5篇 |
数学 | 11篇 |
物理学 | 56篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 24篇 |
2013年 | 32篇 |
2012年 | 30篇 |
2011年 | 34篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 37篇 |
2007年 | 30篇 |
2006年 | 25篇 |
2005年 | 28篇 |
2004年 | 23篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有485条查询结果,搜索用时 343 毫秒
451.
452.
453.
Akiko Hori Masaya Mizutani 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(11):m415-m417
The title complex comprises two Ni2+ ions, four fluorinated ligands and two water molecules in a centrosymmetric dinuclear complex. This compound was crystallized from benzene–CH2Cl2, and two types of crystals, viz. the title benzene tetrasolvate, [Ni2(C15HF10O2)4(H2O)2]·4C6H6, (I), and the previously reported benzene disolvate, [Ni2(C15HF10O2)4(H2O)2]·2C6H6, (II) [Hori et al. (2009). Bull. Chem. Soc. Jpn, 82 , 96–98], were obtained as pseudopolymorphs. In the crystal structure of (I), the four benzene solvent molecules interact closely with all the pentafluorophenyl groups of the complex through arene–perfluoroarene interactions. The molecular structures of the two compounds show essentially the same conformation, although the benzene molecules are accommodated in a columnar packing in (I), while they are isolated from each other in (II). 相似文献
454.
Ryo Tamaki Yuko Arai Daisuke Ichikawa Masaya Inoue Hideyuki Kunugita Kazuhiro Ema 《Journal of luminescence》2008,128(5-6):842-844
Exciton polariton in an organic–inorganic multiple-quantum-well (MQW) single crystal (C4H9NH3)2PbBr4 at low temperature has been investigated by photoluminescence excitation (PLE), reflection, and time-resolved photoluminescence measurements. Since (C4H9NH3)2PbBr4 has ideal two-dimensional excitons with an extremely large oscillator strength and forms self-organized MQW with a very short well-period (d~10 Å), polaritonic coupling among excitons is strong and extends over a large number of wells. Therefore, observed MQW polariton features were the same as those of bulk polaritons. We have also investigated relaxation dynamics of the MQW polariton in the same framework as discussions on bulk polaritons. 相似文献
455.
456.
Toshihiko Yoshimura Kousuke Takeda Hitoshi Sasaki Masaya Tatsui 《Applied Surface Science》2009,256(1):112-115
High compression strength and high ductility spherical nanoballs were produced by electric arc discharge with a carbon electrode containing silicon, oxygen, potassium, and sodium. Compression tests of the nanoballs were conducted by application of a load to nanoballs inserted between two polished sample stages with nanolevel surface roughness. Experimental estimation of the compression strength of nanomaterials was enabled by careful selection and polishing of the sample stage materials. 相似文献
457.
A polystyrene‐cross‐linking tricyclohexylphosphine (PS‐TCP) was synthesized through radical emulsion polymerization of 4‐tert‐butylstyrene as a monomer and tris(trans‐4‐styrylcyclohexyl)phosphine as a threefold cross‐linker. The PS‐TCP showed enhanced ligand performance compared to the corresponding polystyrene‐triphenylphosphine hybrid PS‐TPP and tricyclohexylphosphine in Pd‐catalyzed Suzuki–Miyaura and Buchwald–Hartwig reactions of aryl chlorides. 相似文献
458.
Naoto Hayashi Naoki Okamoto Masaya Onoue Kensuke Yamamoto Junro Yoshino 《Tetrahedron letters》2019,60(25):1663-1666
The 1:0.5 hydrated crystal (I) of 2,2′-(anthra[2,3-b:7,6-b′]difuran-5,11-diylidene)dimalononitrile (1) showed aggregation-induced emission (AIE). However, the structurally similar non-solvated crystal (II) did not show AIE. We found that this was because the lack of water of crystallization changed the geometry of the intermolecular π contacts from two-dimensional in I to three-dimensional in II. 相似文献
459.
Kumazawa K Yoshizawa M Liu HB Kamikawa Y Moriyama M Kato T Fujita M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(8):2519-2524
Compound 1a, which possesses a triphenylene core and six tetraethyleneoxide side chains, shows efficient ionization of M(II)-containing (M=Pd, Pt) complexes in electrospray ionization mass spectrometry (ESI-MS). The molecular ion peaks [M]+, which are hardly detected under common ESI-MS conditions, are clearly observed as their [M x (1a)n]+ (n=1-4) adducts. UV-visible and NMR studies reveal that the electron-rich triphenylene core of 1a binds to the electron-deficient frameworks of the M(II) complexes in solution, giving rise to charge transfer (CT) complexes. We suggest that 1a stabilizes the complexes and promotes efficient ionization through unique donor-acceptor molecular recognition. 相似文献
460.
Kamegawa T Sakai T Matsuoka M Anpo M 《Journal of the American Chemical Society》2005,127(48):16784-16785
Unique inorganic-organic hybrid mesoporous materials incorporating arenetricarbonyl complexes [-C6H4M(CO)3-] (M = Cr, Mo) within their mesoporous frameworks have been successfully prepared by a simple CVD treatment of the phenylene-bridged organosilica mesoporous materials with metal hexacarbonyls [M(CO)6] (M = Cr, Mo). FT-IR and UV-vis investigations revealed that the arenetricarbonyl complexes exist stably even at temperatures above 473 K under vacuum. 相似文献