全文获取类型
收费全文 | 732篇 |
免费 | 25篇 |
国内免费 | 3篇 |
专业分类
化学 | 504篇 |
晶体学 | 9篇 |
力学 | 14篇 |
数学 | 41篇 |
物理学 | 192篇 |
出版年
2021年 | 4篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 6篇 |
2016年 | 18篇 |
2015年 | 15篇 |
2014年 | 5篇 |
2013年 | 20篇 |
2012年 | 40篇 |
2011年 | 42篇 |
2010年 | 20篇 |
2009年 | 29篇 |
2008年 | 48篇 |
2007年 | 29篇 |
2006年 | 32篇 |
2005年 | 40篇 |
2004年 | 32篇 |
2003年 | 38篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 21篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1970年 | 4篇 |
1969年 | 8篇 |
排序方式: 共有760条查询结果,搜索用时 15 毫秒
1.
2.
Prof. Dr. Yasuchika Hasegawa Takafumi Matsui Dr. Yuichi Kitagawa Dr. Takayuki Nakanishi Dr. Tomohiro Seki Prof. Dr. Hajime Ito Prof. Dr. Yuta Nakasaka Prof. Dr. Takao Masuda Prof. Dr. Koji Fushimi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12308-12315
Oxygen-sensitive and near-infrared (NIR) luminescent YbIII coordination polymers incorporating ligands based on pyrene derivatives were synthesized: YbIII–TBAPy and YbIII–TIAPy (TBAPy: 1,3,6,8-tetrakis(p-benzoate)pyrene; TIAPy: 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene). The coordination structures of these materials have been characterized by means of electrospray ionization mass spectrometry, X-ray diffraction analysis, and thermogravimetric analysis. Moreover, the porous structure of YbIII–TIAPy has been evaluated by measuring its N2 adsorption isotherm. The NIR luminescence properties of YbIII–TBAPy and YbIII–TIAPy have been examined by acquiring emission spectra and determining emission lifetimes under air or argon and in vacuo. YbIII–TIAPy exhibited high thermal stability (with a decomposition temperature of 400 °C), intense luminescence (with an emission quantum yield under argon of 6.6 %), and effective oxygen-sensing characteristics. These results suggest that NIR luminescent YbIII coordination polymers prepared using pyrene derivatives could have applications in novel thermo-stable oxygen sensors. 相似文献
3.
The aim of this paper is to find the global solutions of uncertain optimization problems having a quadratic objective function and quadratic inequality constraints. The bounded epistemic uncertainties in the constraint coefficients are represented using either universal or existential quantified parameters and interval parameter domains. This approach allows to model non-controlled uncertainties by using universally quantified parameters and controlled uncertainties by using existentially quantified ones. While existentially quantified parameters could be equivalently considered as additional variables, keeping them as parameters allows maintaining the quadratic problem structure, which is essential for the proposed algorithm. The branch and bound algorithm presented in the paper handles both universally and existentially quantified parameters in a homogeneous way, without branching on their domains, and uses some dedicated numerical constraint programming techniques for finding a robust, global solution. Several examples clarify the theoretical parts and the tests demonstrate the usefulness of the proposed method. 相似文献
4.
Experimental investigation on tunnel sonic boom 总被引:1,自引:0,他引:1
Upon the entrance of a high-speed train into a relatively long train tunnel, compression waves are generated in front of the train. These compression waves subsequently coalesce into a weak shock wave so that a unpleasant sonic boom is emitted from the tunnel exit. In order to investigate the generation of the weak shock wave in train tunnels and the emission of the resulting sonic boom from the train tunnel exit and to search for methods for the reduction of these sonic booms, a 1300 scaled train tunnel simulator was constructed and simulation experiments were carried out using this facility.In the train tunnel simulator, an 18 mm dia. and 200 mm long plastic piston moves along a 40 mm dia. and 25 m long test section with speed ranging from 60 to 100 m/s. The tunnel simulator was tilted 8° to the floor so that the attenuation of the piston speed was not more than 10 % of its entrance speed. Pressure measurements along the tunnel simulator and holographic interferometric optical flow visualization of weak shock waves in the tunnel simulator clearly showed that compression waves, with propagation, coalesced into a weak shock wave. Although, for reduction of the sonic boom in prototype train tunnels, the installation of a hood at the entrance of the tunnels was known to be useful for their suppression, this effect was confirmed in the present experiment and found to be effective particularly for low piston speeds. The installation of a partially perforated wall at the exit of the tunnel simulator was found to smear pressure gradients at the shock. This effect is significant for higher piston speeds. Throughout the series of train tunnel simulator experiments, the combination of both the entrance hood and the perforated wall significantly reduces shock overpressures for piston speeds ofu
p
ranging from 60 to 100 m/s. These experimental findings were then applied to a real train tunnel and good agreement was obtained between the tunnel simulator result and the real tunnel measurements. 相似文献
5.
Yoshikazu Giga Katsuya Inui Alex Mahalov Shin’ya Matsui Jürgen Saal 《Archive for Rational Mechanics and Analysis》2007,186(2):177-224
We prove time local existence and uniqueness of solutions to a boundary layer problem in a rotating frame around the stationary
solution called the Ekman spiral. We choose initial data in the vector-valued homogeneous Besov space for 2 < p < ∞. Here the L
p
-integrability is imposed in the normal direction, while we may have no decay in tangential components, since the Besov space
contains nondecaying functions such as almost periodic functions. A crucial ingredient is theory for vector-valued homogeneous
Besov spaces. For instance we provide and apply an operator-valued bounded H
∞-calculus for the Laplacian in for a general Banach space . 相似文献
6.
7.
Shuichi Hirata Kouichi Tanaka Katsuya Matsui Fernando Arteaga Arteaga Yasushi Yoshida Shinobu Takizawa Hiroaki Sasai 《Tetrahedron: Asymmetry》2013,24(19):1189-1192
The introduction of a 1,3-propanediamine unit at the 3-position of (S)-BINOL using a methylene spacer led to the formation of a chiral bifunctional organocatalyst for the aza-Morita–Baylis–Hillman (aza-MBH) reaction. The organocatalyst 1k mediated aza-MBH transformations with high chemical yields and with up to 82% ee. 相似文献
8.
Yusuke Kawashima Mamoru Satoh Tatsuya Saito Takashi Matsui Fumio Nomura Hiroyuki Matsumoto Yoshio Kodera 《Biomedical chromatography : BMC》2013,27(6):691-694
We report a cyclic sample pooling technique devised in two‐dimensional liquid chromatography–electrospray ionization mass spectrometry (LC‐ESI‐MS) shotgun proteomics that renders deeper proteome coverage; we combined low pH reversed‐phase (RP) LC in trifluoroacetic acid in the first dimension, followed by cyclic sample pooling of the eluate and low‐pH RP‐LC in formic acid in the second dimension. The new protocol has a significantly higher resolving power suitable for LC‐ESI‐MS/MS shotgun proteomics. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Hideki Matsui 《辐射效应与固体损伤》2013,168(1-4):515-516