全文获取类型
收费全文 | 478篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 379篇 |
晶体学 | 9篇 |
力学 | 14篇 |
数学 | 13篇 |
物理学 | 67篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 18篇 |
2012年 | 23篇 |
2011年 | 40篇 |
2010年 | 20篇 |
2009年 | 21篇 |
2008年 | 34篇 |
2007年 | 38篇 |
2006年 | 40篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 14篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有482条查询结果,搜索用时 109 毫秒
1.
Misawa Kensuke Yamaotsu Noriyuki Hirono Shuichi 《Journal of computer-aided molecular design》2021,35(5):601-611
Journal of Computer-Aided Molecular Design - Enhancer of zeste homolog 2 (EZH2) is a histone lysine methyltransferase that is overexpressed in many cancers. Numerous EZH2 inhibitors have been... 相似文献
2.
K. Kogure 《Journal of Terramechanics》1976,13(1):1-14
This paper deals with the external motion resistance of a tracked vehicle caused by rut formation (sinkage) or compression of soil under the tracks. It is shown that the relationship between the applied load and the sinkage for a loading test using a plate is represented by a hyperbola. Based on the above relationship, the external motion resistance caused by the rut formation of a tracked vehicle is estimated by considering the work done by overcoming the ground pressure and the resistance. Further, measurements of the external motion resistance were carried out by using a tracked vehicle and the experimental results are compared with the theoretical ones, and the reliability of the above method is confirmed experimentally. 相似文献
3.
The relationship between contact pressure and sinkage must be represented by a mathematical model to estimate the sinkage and the motion resistance due to a vehicle. In this study an approximate and simple pressure-sinkage model is proposed. This model takes into account the effect of the size of the penetration plate on soil response, and includes two soil values that can be obtained by a single plate penetration test. It is submitted that the sinkage and the motion resistance of a tracked vehicle can be estimated by means of the proposed model. 相似文献
4.
This paper deals with soil thrust exerted by a tracked vehicle. Measurements of the ground pressure beneath the tracks of a tracked vehicle were carried out and it was shown that the ground pressure distribution is approximately represented by discontinuous triangles which have their maxima under the roadwheels. The relationship between soil shear curve (shear stress or force-deformation curve) obtained from shear test and thrust curve (soil thrust-slip ratio curve) of the tracked vehicle is analyzed by using the above mentioned ground pressure distribution, and it is shown that there is a transformation law between both curves. Namely, the thrust curve due to soil shear under any wheel portion is given as a function of soil and vehicle parameters. Further, the reliability of the above method is confirmed experimentally. 相似文献
5.
Hyoe Hatakeyama Shigeo Hirose Tatsuko Hatakeyama Kunio Nakamura Ken Kobashigawa Noriyuki Morohoshi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):743-750
Abstract Polyurethane (PU) sheets and foams having plant components in their network were prepared by using the following procedure. Polyethylene glycol (PEG) was mixed with one of the following; molasses, lignin, woodmeal, or coffee grounds. The mixture obtained was reacted with diphenylmethane diisocyanate (MDI) at room temperature, and precured PUs were prepared. The precured PUs were heat-pressed and PU sheets were obtained. In order to make PU foam, the above mixture was reacted with MDI after the addition of plasticizer, surfactant (silicone oil), catalyst (di-n-butyltin dilaurate), and droplets of water under vigorous stirring. The glass transition temperature, tensile and compression strengths, and Young's modulus of the PU sheets and foams increased with an increasing amount of plant components. This suggests that saccharide and lignin residues act as hard segments in PUs. It was found that the PUs obtained were biodegradable in soil. The rate of biodegradation of the PUs derived from molasses and coffee grounds was between that of cryptomeria (Cryptomeria japonica) and beech (Fagus sieboldi). 相似文献
6.
Takayuki MaruyamaYasuyuki Fujie Noriyuki OyaEisuke Hosaka Aki KanazawaDaisuke Tanaka Yoshiyuki HattoriJiro Motoyoshiya 《Tetrahedron》2011,67(36):6927-6933
The control of peroxyoxalate chemiluminescence (PO-CL) by the coordination of nitrogen-containing ligands and metal cations was investigated. Turning the CL off and on was done by PO-CL using 15-monoazacrown-5-tethered anthracene and alkali metal ions. CL quenching and regeneration was also observed in the separated molecular system of 15-monoazacrown-5 and the fluorophores. CL quenching by a number of ligands bearing dipicolylamino groups was evaluated by these PO-CL reactions and found to be closely related to their oxidation potentials, which is dependent on the Weller rate law for electron exchange and this provides strong support for the existence of the CIEEL PO-CL process. When Zn2+ or Cu2+ are added to the PO-CL system quenched by the ligand, N-[2-(2,2′-dipicolylamino)ethyl]aniline, CL was turned on because the electron donating ability of the ligands was modulated. This was controlled by the coordination of the studied metal ions and, therefore, this system results in CL because of host-guest interactions. 相似文献
7.
Yousuke Yamada Dr. Mariko Kitajima Dr. Noriyuki Kogure Dr. Sumphan Wongseripipatana Prof. Dr. Hiromitsu Takayama 《化学:亚洲杂志》2011,6(1):166-173
Seven new indole alkaloids were isolated from the roots of Gelsemium elegans Benth. and their structures were determined by spectroscopic analysis and chemical transformation from known alkaloids. Kounaminal ( 1 ) is a new koumine‐type alkaloid that contains an unusual aminal moiety. Humantenoxenine ( 2 ) and 15‐hydroxyhumantenoxenine ( 3 ) are humantenine‐type alkaloids that contain a novel β‐amino‐α,β‐unsaturated ketone residue. The other four novel alkaloids are two gelsedilam‐related and two gelsenicine‐related alkaloids. 相似文献
8.
Masaya Enomoto Noriyuki KidaNorimichi Kojima Isao WatanabeTakao Suzuki Yasuyuki Ishii 《Polyhedron》2011,30(18):3137-3139
We have investigated the magnetic properties of iron mixed-valence complexes, (n-CnH2n+1)4N[FeIIFeIII(dto)3] (dto = C2O2S2, n = 3, 5), in which not only a ferromagnetic transition but also a novel charge transfer phase transition (CTPT) take place [1]. This CTPT can be observed under ambient pressure for n = 3, while it appears abruptly above 0.5 GPa for n = 5 [2]. Recently, we have measured the muon spin relaxation (μSR) for the CTPT of n = 3, which revealed the dynamical process of electron-transfer between FeII and FeIII and its frequency was estimated at about 0.1 MHz [3]. To investigate the pressure induced CTPT for n = 5, we carried out the μSR measurement for n = 5 at 150 K between 0.30 and 0.64 GPa with the 4He gas-operated pressure system. The asymmetry of the muon spin relaxation for n = 5 with Cu-Be pressure cell was almost constant up to 0.55 GPa, while it rapidly decreased with increasing pressure above 0.60 GPa. This result shows that the applied pressure causes the spin fluctuation due to the CTPT, which induces the decrease of the asymmetry of muon spin relaxation. This experiment can correctly decide the phase transition pressure from the absence to the appearance of the CTPT for n = 5. 相似文献
9.
Noriyuki Yoshii Yoshimichi Andoh Susumu Okazaki 《Journal of computational chemistry》2020,41(9):940-948
We derived a new expression for the electrostatic interaction of three-dimensional charge-neutral systems with two-dimensional periodic boundary conditions (slab geometry) using a fast multipole method (FMM). Contributions from all the image cells are expressed as a sum of real and reciprocal space terms, and a self-interaction term. The reciprocal space contribution consists of two parts: zero and nonzero terms of the absolute value of the reciprocal lattice vector. To test the new expressions, electrostatic interactions were calculated for a randomly placed charge distribution in a cubic box and liquid water produced by molecular dynamics calculation. The accuracy could be controlled by the degree of expansion of the FMM. In the present expression, the computational complexity of the electrostatic interaction of N-particle systems is order N, which is superior to that of the conventional two-dimensional periodic Ewald method for a slab geometry and the particle mesh Ewald method with a large empty space at an interface of the unit cell. © 2020 Wiley Periodicals, Inc. 相似文献
10.
Direct Asymmetric Mannich‐Type Reaction of α‐Isocyanoacetates with Ketimines using Cinchona Alkaloid/Copper(II) Catalysts 下载免费PDF全文
Masashi Hayashi Masaru Iwanaga Noriyuki Shiomi Dr. Daisuke Nakane Prof. Dr. Hideki Masuda Prof. Dr. Shuichi Nakamura 《Angewandte Chemie (International ed. in English)》2014,53(32):8411-8415
The enantioselective direct Mannich‐type reaction of ketimines with α‐isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α‐isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,β‐diamino acids. 相似文献