全文获取类型
收费全文 | 257篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 190篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 24篇 |
物理学 | 42篇 |
出版年
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 22篇 |
2012年 | 16篇 |
2011年 | 11篇 |
2010年 | 3篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 21篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 22篇 |
2003年 | 17篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有260条查询结果,搜索用时 31 毫秒
251.
Hiroki Sano Tamotsu Izumida Ken-Ichi Mitani Tomoyoshi Ohwada Kichi-Suke Saito 《Central European Journal of Mathematics》2014,12(5):778-786
In [Mineno K., Nakamura Y., Ohwada T., Characterization of the intermediate values of the triangle inequality, Math. Inequal. Appl., 2012, 15(4), 1019–1035] there was established a norm inequality which characterizes all intermediate values of the triangle inequality, i.e. C n that satisfy 0 ≤ C n ≤ Σ j=1 n ‖x j ‖ ? ‖Σ j=1 n x j ‖, x 1,...,x n ∈ X. Here we study when this norm inequality attains equality in strictly convex Banach spaces. 相似文献
252.
Anraku R Mawatari K Tokeshi M Nara M Asai T Hattori A Kitamori T 《Electrophoresis》2008,29(9):1895-1901
Thermal lens microscope (TLM) is a sensitive detection method for nonfluorescent molecules and widely applied to detection in a capillary or on a microchip. In this paper, we developed a flexible design tool for TLM systems to meet various applications utilizing a microspace. The TL effect was modeled, including signal processing, and calculated by combining fluidic dynamics and wave optics software. The coincidence of the calculations and experiments was investigated by measuring the effects of optical path length or focus positions of the excitation beams on TL signals which are quite difficult to calculate by a conventional method. Good agreement was shown and the applicability of the TLM design tool was verified. 相似文献
253.
We have developed a circular-dichroism thermal lens microscope for UV wavelengths (UV-CD-TLM), for the first time, to realize
sensitive chiral analysis on a microchip. Quasi-continuous-wave phase modulation of a pulsed UV laser was used to generate
left-circularly polarized light and right-circularly polarized light and to detect the generated TL signal amplitude and phase
with a lock-in amplifier. The amplitude and phase were used to determine the concentration and chirality, respectively, of
a sample. The basic principle of UV-CD-TLM for chiral analysis on a microchip was verified by measuring aqueous solutions
of optically active camphorsulfonic acids (CSA). Lower limits of detection (LOD) were calculated at S/N = 2 and were 8.7 × 10−4 mol L−1 (ΔA = 5.2 × 10−6 Abs.) for (+)-CSA and 8.4 × 10−4 mol L−1 (ΔA = 5.0 × 10−6 Abs.) for (−)-CSA. In terms of number of molecules, LODs for UV-CD-TLM were calculated to be 8.7 fmol and 8.4 fmol, respectively.
This is at least three orders of magnitude lower than previously obtained. The applicability of UV-CD-TLM for chiral analysis
on a microchip was verified.
Figure Sensitive chiral analysis by thermal lens microscope (TLM) 相似文献
254.
255.
S Harada T Sakai K Takasu K Yamada Y Yamamoto K Tomioka 《The Journal of organic chemistry》2012,77(17):7212-7222
Enantio- and diastereoselective one-pot synthesis of three- to seven-membered cis-azaheterocycles was achieved using a triggered asymmetric conjugate addition reaction of lithium amide with an enoate, followed by alkylation of the resulting lithium enolate with α,ω-dihaloalkane and N-alkylation. Isomerization of cis-azaheterocycles with a base yielded the trans-product, constituting a one-pot synthesis of cis-azacycles and a two-step synthesis of trans-azacycles. The four-step asymmetric synthesis of nemonapride highlights the general utility of the method. 相似文献
256.
Kihoon Jang Yan Xu Kae Sato Yo Tanaka Kazuma Mawatari Takehiko Kitamori 《Mikrochimica acta》2012,176(1-2):49-55
Platinum nanoparticles were electrodeposited onto a film of dihexadecyl hydrogen phosphate deposited on a glassy carbon electrode (GCE) and modified with dispersed acetylene black. Scanning electron microscopy and electrochemical impedance spectroscopy revealed that this nanocomposite has a uniform nanostructure and a large surface area that enables fast electron-transfer kinetics. The modified GCE showed high electrocatalytic activity for the oxidation of nitric oxide (NO). Under optimal conditions, the oxidation peak current of nitric oxide is linearly related to the concentration of NO in the concentration range between 0.18 and 120?μM, and the detection limit is as low as 50?nM (at an S/N of 3). The modified electrode was successfully applied to sensing of NO as released from rat liver. Figure
Acetylene black (AB) was dispersed with dihexadecyl hydrogen phosphate (DHP) and modified on the surface of glassy carbon electrode (GCE) to fabricate AB/GCE, after activating in NaOH solution, the AB film became more porous and loosened, then through electrodepositing Pt nanoparticles (PtNPs) on the activated AB film, PtNP/AB/GCE was obtained, which was denoted as NO electrochemical sensor. 相似文献
257.
Xu Y Jang K Yamashita T Tanaka Y Mawatari K Kitamori T 《Analytical and bioanalytical chemistry》2012,402(1):99-107
By combining cell technology and microchip technology, innovative cellular biochemical tools can be created from the microscale
to the nanoscale for both practical applications and fundamental research. On the microscale level, novel practical applications
taking advantage of the unique capabilities of microfluidics have been accelerated in clinical diagnosis, food safety, environmental
monitoring, and drug discovery. On the other hand, one important trend of this field is further downscaling of feature size
to the 101–103 nm scale, which we call extended-nano space. Extended-nano space technology is leading to the creation of innovative nanofluidic
cellular and biochemical tools for analysis of single cells at the single-molecule level. As a pioneering group in this field,
we focus not only on the development of practical applications of cellular microchip devices but also on fundamental research
to initiate new possibilities in the field. In this paper, we review our recent progress on tissue reconstruction, routine
cell-based assays on microchip systems, and preliminary fundamental method for single-cell analysis at the single-molecule
level with integration of the burgeoning technologies of extended-nano space. 相似文献
258.
Hosoi H Kawai N Hagiwara H Suzuki T Nakazaki A Takao K Umezawa K Kobayashi S 《Chemical & pharmaceutical bulletin》2012,60(1):137-143
We describe the total synthesis and structural determination of (+)-akaterpin (1), an inhibitor of phosphatidylinositol-specific phospholipase C (PI-PLC). The key features of the synthetic strategy include the resolution of β,γ-unsaturated ketone (±)-2a with chiral sulfoximine 6. The absolute stereochemistry was determined by comparison of the specific optical rotation data of (+)-1 and (-)-1 with that of natural akaterpin. 相似文献
259.
Ken-Ichi Mitani Kichi-Suke Saito 《Nonlinear Analysis: Theory, Methods & Applications》2009,71(11):310-5247
In [M. Kato and L. Maligranda, On James and Jordan–von Neumann constants of Lorentz sequence spaces, J. Math. Anal. Appl. 258 (2001) 457–465], it is an open problem to compute the James constant of the dual space of two dimensional Lorentz sequence space d(2)(w,q). In this paper, we shall determine the dual norm of d(2)(w,q) and completely compute the James constant of d(2)(w,q). 相似文献
260.
Asymmetric trans-addition reactions of simple olefins have been performed by using optically active 2-selenobinaphthyls 1 , 2a–g. Introduction of an amide group at the 2′-position in the binaphthyl skeleton enhances considerably the diastereomeric excess (de) of the asymmetric methoxyselenenylation. In the case of trans-olefins, introduction of another chiral center in the amide group further enhances the de due to double stereodifferentiation between the (R)-binaphthyl skeleton and the chiral amide group introduced at the 2′-position in the binaphthyl skeleton. The use of chiral nucleophiles is also effective to enhance the de for symmetrical cis-olefins. 相似文献