全文获取类型
收费全文 | 443篇 |
免费 | 3篇 |
专业分类
化学 | 229篇 |
晶体学 | 3篇 |
力学 | 5篇 |
数学 | 2篇 |
物理学 | 207篇 |
出版年
2022年 | 3篇 |
2020年 | 2篇 |
2018年 | 4篇 |
2016年 | 2篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 23篇 |
2011年 | 22篇 |
2010年 | 9篇 |
2009年 | 25篇 |
2008年 | 19篇 |
2007年 | 28篇 |
2006年 | 17篇 |
2005年 | 24篇 |
2004年 | 15篇 |
2003年 | 21篇 |
2002年 | 20篇 |
2001年 | 10篇 |
2000年 | 14篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 15篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有446条查询结果,搜索用时 15 毫秒
51.
Yanfang Geng Keisuke Tajima Kazuhito Hashimoto 《Macromolecular rapid communications》2011,32(18):1478-1483
A regioregular poly[4′‐dodecyl‐3‐(1H,1H,2H,2H‐perfluorooctyl)‐2,2′‐bithiophene] (P3DDFT) with alternating alkyl and semifluoroalkyl side chains were synthesized. Short ethylene spacer between perfluorohexyl part and thiophene did not largely affect the absorption and emission properties of the polythiophene backbone in comparison with poly(3‐dodecylthiophene) (P3DDT). P3DDFT showed a larger onset of the oxidation potential (+0.17 V) observed by cyclic voltamogram due to the electron withdrawing effect of the fluoroalkyl part. Thermal analysis and X‐ray diffraction patterns indicated that P3DDFT in the solid state forms a semicrystalline lamellar structure that is similar to that of P3DDT. Ultraviolet photoemission spectroscopy was also used to investigate their electron structure in the films. Comparison of hole mobilities in the films suggested that P3DDFT could have a less ordered packing structure compared to P3DDT both in the bulk and at the dielectric interface.
52.
Noriaki Nishiguchi Takafumi Kinuta Yoko Nakano Dr. Takunori Harada Dr. Nobuo Tajima Tomohiro Sato Prof. Dr. Michiya Fujiki Prof. Dr. Reiko Kuroda Prof. Dr. Yoshio Matsubara Dr. Yoshitane Imai 《化学:亚洲杂志》2011,6(4):1092-1098
The solid‐state chiral optical properties of a 4‐(2‐arylethynyl)‐benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4‐(2‐arylethynyl)‐benzoic acid component molecule rather than the chirality of the amine component molecule. 相似文献
53.
Imai M Sato A Udono H Imai Y Tajima H 《Dalton transactions (Cambridge, England : 2003)》2011,40(16):4045-4047
A ternary type-I Si clathrate K(8)Ga(8)Si(38) has been revealed to be an indirect band gap semiconducting material with an energy gap (E(g)) of approximately 0.10 eV, which is much smaller than the calculated E(g) value that is 0.15 eV wider than E(g) of elemental Si with the diamond-type structure. 相似文献
54.
55.
56.
Yoshitane Imai Kensaku Kamon Nobuo Tajima Reiko Kuroda Yoshio Matsubara 《Tetrahedron》2007,63(48):11928-11932
Chiral charge-transfer (CT) complexes composed of a chiral 1,1′-bi-2-naphthol cluster as the electron donor and 1,1′-dibenzyl-4,4′-bipyridinium dichloride as the electron acceptor serve as a host system for molecular recognition. CT complexes that include guest alcohols show different diffuse reflectance spectra (DRS) depending on the included guest. 相似文献
57.
58.
Yoshinao Kumagai Yuuki Enatsu Masanari Ishizuki Yuki Kubota Jumpei Tajima Toru Nagashima Hisashi Murakami Kazuya Takada Akinori Koukitu 《Journal of Crystal Growth》2010,312(18):2530-2536
Void formation at the interface between thick AlN layers and (0 0 0 1) sapphire substrates was investigated to form a predefined separation point of the thick AlN layers for the preparation of freestanding AlN substrates by hydride vapor phase epitaxy (HVPE). By heating 50–200 nm thick intermediate AlN layers above 1400 °C in a gas flow containing H2 and NH3, voids were formed beneath the AlN layers by the decomposition reaction of sapphire with hydrogen diffusing to the interface. The volume of the sapphire decomposed at the interface increased as the temperature and time of the heat treatment was increased and as the thickness of the AlN layer decreased. Thick AlN layers subsequently grown at 1450 °C after the formation of voids beneath the intermediate AlN layer with a thickness of 100 nm or above self-separated from the sapphire substrates during post-growth cooling with the aid of voids. The 79 μm thick freestanding AlN substrate obtained using a 200 nm thick intermediate AlN layer had a flat surface with no pits, high optical transparency at wavelengths above 208.1 nm, and a dislocation density of 1.5×108 cm−2. 相似文献
59.
Photonic crystal fibers are attractive since we can realize a wide variety of unique features in the PCFs, which cannot be realized in conventional single-mode fibers. We describe recent progress in the PCF. 相似文献
60.
Chen KF Hara K Hazumi M Higuchi T Miyabayashi K Nakahama Y Sumisawa K Tajima O Ushiroda Y Yusa Y Abe K Abe K Adachi I Aihara H Anipko D Arinstein K Aulchenko V Aushev T Aziz T Bakich AM Balagura V Banerjee S Barberio E Barbero M Bay A Belous K Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Choi SK Choi Y Choi YK Chuvikov A Cole S Dalseno J Danilov M Dash M Dragic J Drutskoy A Eidelman S Epifanov D Fratina S Garmash A 《Physical review letters》2007,98(3):031802
We present improved measurements of CP-violation parameters in B(0) --> phiK(0), eta(')K(0), KS(0)KS(0)KS(0) decays based on a sample of 535 x 10(6) BB pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We obtain sin2phi1(eff)=+0.64+/-0.10(stat)+/-0.04(syst) for B(0) --> eta(')K(0), +0.50+/-0.21(stat)+/-0.06(syst) for B(0) --> phiK(0), and +0.30+/-0.32(stat)+/-0.08(syst) for B(0) --> KS(0)KS(0)KS(0) decays. We have observed CP violation in the B(0) --> eta(')K(0) decay with a significance of 5.6 standard deviations. We also perform an improved measurement of CP asymmetries in B(0) --> J/psiK(0) decays and obtain sin2phi1=+0.642+/-0.031(stat)+/-0.017(syst). 相似文献