全文获取类型
收费全文 | 483篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
化学 | 471篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 9篇 |
物理学 | 31篇 |
出版年
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 24篇 |
2012年 | 35篇 |
2011年 | 41篇 |
2010年 | 19篇 |
2009年 | 8篇 |
2008年 | 35篇 |
2007年 | 24篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 31篇 |
2003年 | 20篇 |
2002年 | 23篇 |
2001年 | 3篇 |
2000年 | 12篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1968年 | 3篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有515条查询结果,搜索用时 15 毫秒
131.
Wakahara T Nikawa H Kikuchi T Nakahodo T Rahman GM Tsuchiya T Maeda Y Akasaka T Yoza K Horn E Yamamoto K Mizorogi N Slanina Z Nagase S 《Journal of the American Chemical Society》2006,128(44):14228-14229
We show here that La@C72 has a non-IPR cage, unique electronic properties, and high reactivity by the spectroscopic and X-ray crystallographic analysis and the theoretical study. The isolation of La@C72 as a stable derivative might constitute an important stepping-stone on the way to isolation of these unknown metallofullerenes and open new material science of metallofullerenes. 相似文献
132.
One-electron reduction of kinetically stabilized dipnictenes: synthesis of dipnictene anion radicals
Sasamori T Mieda E Nagahora N Sato K Shiomi D Takui T Hosoi Y Furukawa Y Takagi N Nagase S Tokitoh N 《Journal of the American Chemical Society》2006,128(38):12582-12588
The redox behavior of kinetically stabilized dipnictenes, BbtE=EBbt [E = P, Sb, Bi; Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl], was systematically disclosed using cyclic voltammetry and theoretical calculations. It was found that they showed reversible one-electron redox couples in the reduction region. The anion radical species of the Bbt-substituted diphosphene and distibene were successfully synthesized by the reduction of the corresponding neutral dipnictenes (BbtP=PBbt and BbtSb=SbBbt). Their structures were reasonably characterized by ESR, UV-vis, and Raman spectroscopy, and the distibene anion radical was structurally characterized by X-ray crystallographic analysis. 相似文献
133.
Sugiyama Y Sasamori T Hosoi Y Furukawa Y Takagi N Nagase S Tokitoh N 《Journal of the American Chemical Society》2006,128(3):1023-1031
The reduction of an overcrowded (E)-1,2-dibromodigermene, Bbt(Br)Ge=Ge(Br)Bbt (2) [Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl], with KC8 afforded a stable digermyne, BbtGe[triple bond]GeBbt (1). The Ge[triple bond]Ge triple-bond characters of 1 were revealed by the X-ray crystallographic analysis and spectroscopic studies (UV/vis and Raman spectra) together with theoretical calculations. The Ge[triple bond]Ge bond lengths of the two nonidentical molecules of 1 observed in the unit cell were shorter than that of the previously reported digermyne, Ar'Ge[triple bond]GeAr' (Ar' = 2,6-Dip2C6H3, Dip = 2,6-diisopropylphenyl). 相似文献
134.
Tsuchiya T Sato K Kurihara H Wakahara T Maeda Y Akasaka T Ohkubo K Fukuzumi S Kato T Nagase S 《Journal of the American Chemical Society》2006,128(45):14418-14419
Complexation behavior of the paramagnetic La@C82 metallofullerene with organic donor molecules (D) in solution is investigated. It is revealed that La@C82 and D form a 1:1 complex as a result of electron transfer. La@C82 and D are in equilibrium with [La@C82]-/[D]*+ in solution, which is readily controllable by changing the temperature and solvent. 相似文献
135.
Maeda Y Kanda M Hashimoto M Hasegawa T Kimura S Lian Y Wakahara T Akasaka T Kazaoui S Minami N Okazaki T Hayamizu Y Hata K Lu J Nagase S 《Journal of the American Chemical Society》2006,128(37):12239-12242
The dispersion of small-diameter single-walled carbon nanotubes (SWNTs) produced by the CoMoCAT method in tetrahydrofuran (THF) with the use of amine was studied. The absorption, photoluminescence, and Raman spectroscopies showed that the dispersion and centrifugation process leads to an effective separation of metallic SWNTs from semiconducting SWNTs. Since this method is simple and convenient, it is highly applicable to an industrial utilization for widespread applications of SWNTs. 相似文献
136.
Kataoka T Kidowaki M Zhao C Minamikawa H Shimizu T Ito K 《The journal of physical chemistry. B》2006,110(48):24377-24383
Thermoreversible gelation and microphase formation of aqueous solutions of a methylated polyrotaxane (MePR) were investigated by means of differential scanning microcalorimetry, rheometry, and X-ray diffractometry (XRD). The aqueous solutions of MePR show a lower critical solution temperature (LCST) and form an elastic gel with increasing temperature. The sol-gel transition of the MePR solutions was induced by formation and deformation of aggregates of methylated alpha-cyclodextrins (alpha-CDs) of polyrotaxane due to hydrophobic dehydration and hydration, respectively. The XRD investigation revealed localization and highly ordered arrangement of methylated alpha-CDs along the PEG chain in the gel. The arrangement of CDs was also reflected by the changes in elasticity and long relaxation behavior of the solution around the sol-gel transition. The quasiequilibrium shear modulus of MePR solutions showed the critical phenomena against temperature. The scaling exponents measured at two different concentrations were almost equal to the values predicted by a gel percolation theory. Therefore, the heat-induced gelation of aqueous MePR solutions is well explained by a model in which clusters assembled with methylated alpha-CDs are gradually connected to the network as the temperature increases. 相似文献
137.
Yamada M Minowa M Sato S Kako M Slanina Z Mizorogi N Tsuchiya T Maeda Y Nagase S Akasaka T 《Journal of the American Chemical Society》2010,132(50):17953-17960
Thermal carbosilylation of endohedral dimetallofullerene La(2)@I(h)-C(80) with silirane (silacyclopropane) is reported herein for the first time. Two diastereomers of the carbosilylated La(2)@I(h)-C(80) have been isolated and characterized. The fascinating molecular structure of one diastereomer of the carbosilylated derivatives has been determined unambiguously using X-ray crystallographic analysis. Detailed characteristics of the molecular structures including their metal atom movements have also been revealed using NMR spectroscopic studies and computational calculations. Results revealed that two La atoms move dynamically inside the carbon sphere. Furthermore, electrochemical study has demonstrated that carbosilylation is effective to fine-tune the La(2)@I(h)-C(80) electronic properties. 相似文献
138.
139.
140.
[reaction: see text] We describe a new approach for the solid-phase synthesis of indoles 1 that involves a one-pot release and cyclization reaction of a solid-supported hydrazone through a Wang-type linker. Using this solid-phase methodology, we accomplished the synthesis of 40 naltrindole derivatives. 相似文献