全文获取类型
收费全文 | 135篇 |
免费 | 0篇 |
专业分类
化学 | 101篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 7篇 |
物理学 | 24篇 |
出版年
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 2篇 |
1968年 | 3篇 |
1957年 | 1篇 |
排序方式: 共有135条查询结果,搜索用时 140 毫秒
71.
Yuichiro Haramoto Yuko Kawada Atushi Mochizuki Masato Nanasawa Seiji Ujiie Masahiro Funahashi Kohki Hiroshima Takamasa Kato 《Liquid crystals》2005,32(7):909-912
We report a new possibility for liquid crystalline organic semiconductors. These materials exhibit smectic liquid crystalline phases, in which the molecules assume a smectic molecular order by self-assembly. Because of the strong dispersion force among long alkyl chains, on cooling, smectic molecular order was retained at room temperature. A charge transport ability was also retained. The conductivity of a device having smectic liquid crystalline order is about 5×107 that of a device with no smectic order. The current - voltage characteristic of the device has a very sharp increase at low threshold voltage (5 V). A high carrier mobility of 1.8×10-2 was observed in the smectic phase of one of the compounds studied (e). 相似文献
72.
Mitsuhiro IwamotoHatsuo Kawada Tomoyuki TanakaMasahisa Nakada 《Tetrahedron letters》2003,44(39):7239-7243
Highly enantio- and stereoselective preparation of some new chiral building blocks with baker's yeast or the CBS catalyst is described. 相似文献
73.
Let R k,s(n) denote the number of solutions of the equation \({n= x^2 + y_1^k + y_2^k + \cdots + y_s^k}\) in natural numbers x, y 1, . . . , y s . By a straightforward application of the circle method, an asymptotic formula for R k,s(n) is obtained when k ≥ 3 and s ≥ 2k–1 + 2. When k ≥ 6, work of Heath-Brown and Boklan is applied to establish the asymptotic formula under the milder constraint s ≥ 7 · 2k–4 + 3. Although the principal conclusions provided by Heath-Brown and Boklan are not available for smaller values of k, some of the underlying ideas are still applicable for k = 5, and the main objective of this article is to establish an asymptotic formula for R 5,17(n) by this strategy. 相似文献
74.
H. Watanabe K. YamaguchiA. Odahara T. SumikamaS. Nishimura K. YoshinagaZ. Li Y. MiyashitaK. Sato L. PróchniakH. Baba J.S. BerrymanN. Blasi A. Bracco F. Camera J. ChibaP. Doornenbal S. GoT. Hashimoto S. HayakawaC. Hinke N. HinoharaE. Ideguchi T. IsobeY. Ito D.G. JenkinsY. Kawada N. KobayashiY. Kondo R. KrückenS. Kubono G. Lorusso T. NakanoT. Nakatsukasa M. Kurata-NishimuraH.J. Ong S. OtaZs. Podolyák H. SakuraiH. Scheit K. SteigerD. Steppenbeck K. SugimotoK. Tajiri S. TakanoA. Takashima T. TeranishiY. Wakabayashi P.M. WalkerO. Wieland H. Yamaguchi 《Physics letters. [Part B]》2011,704(4):270-275
75.
Shouhei Kawada Eri Kodama Keisuke Sato Shuhei Ogawa Masaya Watanabe Hikaru Okubo Shinya Sasaki 《Surface and interface analysis : SIA》2019,51(1):17-20
The interfacial structures of cyano-based room-temperature ionic liquids play a very important role in reducing friction. However, the presence of water impairs their tribological performance. The interfacial structures and friction forces of 1-ethyl-3-methylimidazolium dicyanamide, [EMIM][DCN], and the effect of water on these structures and forces were investigated using atomic force microscopy. In addition, the interaction of water and [EMIM][DCN] was evaluated using Fourier-transform infrared (FT-IR) spectroscopy. Multiple repulsive layers were observed in the [EMIM][DCN] solution. This solution showed low friction force because these repulsive layers worked as protective layers against friction. On the other hand, the specific repulsive layer characteristics of [EMIM][DCN] could not be observed in a [EMIM][DCN] + 2 wt% H2O solution. FT-IR results indicated that the layer structure of [EMIM][DCN] was disturbed by the addition of H2O. Therefore, the solution containing water exhibited a high friction force. 相似文献
76.
77.
78.
79.
80.
The treatment of (15)N(4)-labeled cytidine N(3)-oxide and (15)N(4)-labeled 2'-deoxycytidine N(3)-oxide, prepared from the appropriate unprotected uridines in three reaction steps, with benzyl bromide in the presence of excess lithium methoxide allowed the smooth occurrence of their Dimroth rearrangement even under mild conditions leading to the corresponding (15)N(3)-labeled uridine 4-O-benzyloximes which can easily undergo the reductive N-O bond cleavage to give the desirable (15)N(3)-labeled cytosine nucleosides in high total yields. 相似文献