全文获取类型
收费全文 | 275篇 |
免费 | 19篇 |
专业分类
化学 | 218篇 |
晶体学 | 8篇 |
力学 | 9篇 |
数学 | 18篇 |
物理学 | 41篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 19篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 2篇 |
1937年 | 2篇 |
排序方式: 共有294条查询结果,搜索用时 93 毫秒
101.
Guanglin Huang Shota Hasegawa Dr. Yoshifumi Hashikawa Dr. Yuki Ide Prof. Dr. Takashi Hirose Prof. Dr. Yasujiro Murata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103836
An H2O2 molecule was isolated inside hydroxylated open-cage fullerene derivatives by mixing an H2O2 solution with a precursor molecule followed by reduction of one of carbonyl groups on its orifice. Depending on the reduction site, two structural isomers for H2O2@open-fullerenes were obtained. A high encapsulation ratio of 81 % was attained at low temperature. The structures of the peroxosolvate complexes thus obtained were studied by 1H NMR spectroscopy, X-ray analysis, and DFT calculations, showing strong hydrogen bonding between the encapsulated H2O2 and the hydroxy group located at the center of the orifice. This OH group was found to act as a kinetic stopper, and the formation of the hydrogen bonding caused thermodynamic stabilization of the H2O2 molecule, both of which prevent its escape from the cage. One of the peroxosolvates was isolated by HPLC, affording H2O2@open-fullerene with 100 % encapsulation ratio, likely due to the intramolecular hydrogen-bonding interaction. 相似文献
102.
103.
Tanabe M Ishikawa N Chiba M Ide T Osakada K Tanase T 《Journal of the American Chemical Society》2011,133(46):18598-18601
A complex with a planar hexagonal Pd(4)Ge(3) core, [Pd{Pd(dmpe)}(3)(μ(3)-GePh(2))(3)], was synthesized and characterized by X-ray and NMR measurements as well as by DFT calculations. 4-tert-Butylbenzenethiol converted the Pd(4) complex into a hexapalladium complex, [{Pd(3)(μ-GePh(2))(2)(μ-H)(μ(3)-GePh(2)(SC(6)H(4)(t)Bu-4))}(2)(μ-dmpe)], composed of two Pd(3)Ge(3) units bridged by a dmpe ligand. The addition of CuI or AgI to the Pd(4) complex yielded [Pd(μ-MI){Pd(dmpe)}(3)(μ(3)-GePh(2))(3) ] (M = Cu, Ag), in which Cu or Ag bridges a Pd-Pd bond of the Pd(4)Ge(3) core. The CuI adducts in solution undergo a pivot motion of the CuI on the surface of the Pd(4)Ge(3) plane on the NMR time scale. 相似文献
104.
Yoshitaka Tsuchido Dr. Yuji Suzaki Dr. Tomohito Ide Prof. Dr. Kohtaro Osakada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4762-4771
4,6‐Bis(2‐hydroxyphenyl)‐2‐alkylpyrimidines with two anthryl or 9‐ethylnylanthryl substituents at the positions para to the OH groups prefer a U‐shaped conformation supported by two intramolecular OH ??? N hydrogen bonds in the solid state and in CDCl3 solution. The compound with a hexyl substituent on the pyrimidine group and two 9‐ethynylanthryl arms at the hydroxyphenyl groups forms a 1:1 complex with 2,4,7‐trinitrofluorenone. Its association constant Ka was estimated to be 2100 M ?1 at 298 K, which is larger than those of other molecular tweezers (Ka<1000 M ?1). DFT calculations suggested that the complex adopts a stable conformation supported by intramolecular hydrogen bonds among the OH groups and the pyrimidine ring as well as by intermolecular π–π interaction between the anthryl groups and 2,4,7‐trinitrofluorenone. Addition of nBu4NF to a solution of the molecular tweezers or their complexes causes the cleavage of one or two OH ??? N hydrogen bonds, formation of new O ??? HF hydrogen bonds, and changes in the molecular conformation. The resulting structure of the molecular tweezers contains nonparallel anthryl groups, which do not bind the guest molecule. Photochemical measurements on 4,6‐bis(2‐hydroxyphenyl)‐2‐methylpyrimidine with two anthryl substituents showed negligible luminescence (quantum yield ?<0.01), owing to photoinduced electron transfer of the molecule with a U‐shaped structure. However, the O‐hexylated compound exhibits emission from the anthryl groups with ?=0.39. 相似文献
105.
The thermal decomposition rate of N2O5 in 760 Torr of air as a function of temperature between 314 and 348 K has been investigated using the technique of pulsed laser cavity ring-down spectroscopy (CRDS) detection of NO3 radicals at 662 nm. The Arrhenius expression of the thermal decomposition rates determined by the CRDS experiments, which is incorporated with literature values down to 263 K, is given by 1.36 × 1015 exp{(−11300 ± 200)/T} s−1 over the temperature range 263–348 K. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 679–684, 2008 相似文献
106.
Distributions of fluid temperature and its fluctuation are measured across a R-113 subcooled boiling flow channel with heat fluxes up to the CHF. A microthermocouple probe associated with an electric compensation circuit for the time constant is used for this purpose. Applying statistical treatments to the recorded temperature fluctuation, the heat transfer process in the flow and the characteristics of the bubbles flowing close to the heated surface are investigated. For high heat fluxes nearby the CHF, some bubbles adjacent to the heated surface show a clear trend to coalesce to large volume bubbles with relatively long passing periods, suggesting a mechanism of departure from nucleate boiling by periodical wall temperature rise due to momentary liquid film dryout underneath the large bubbles. 相似文献
107.
108.
Multimetal‐Substituted Epsilon‐Iron Oxide ϵ‐Ga0.31Ti0.05Co0.05Fe1.59O3 for Next‐Generation Magnetic Recording Tape in the Big‐Data Era
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prof. Shin‐ichi Ohkoshi Dr. Asuka Namai Marie Yoshikiyo Dr. Kenta Imoto Kazunori Tamazaki Koji Matsuno Osamu Inoue Tsutomu Ide Kenji Masada Masahiro Goto Takashi Goto Takayuki Yoshida Tatsuro Miyazaki 《Angewandte Chemie (International ed. in English)》2016,55(38):11403-11406
From the viewpoints of large capacity, long‐term guarantee, and low cost, interest in magnetic recording tapes has undergone a revival as an archive storage media for big data. Herein, we prepared a new series of metal‐substituted ?‐Fe2O3, ?‐GaIII0.31TiIV0.05CoII0.05FeIII1.59O3, nanoparticles with an average size of 18 nm. Ga, Ti, and Co cations tune the magnetic properties of ?‐Fe2O3 to the specifications demanded for a magnetic recording tape. The coercive field was tuned to 2.7 kOe by introduction of single‐ion anisotropy on CoII (S=3/2) along the c‐axis. The saturation magnetization was increased by 44 % with GaIII (S=0) and TiIV (S=0) substitution through the enhancement of positive sublattice magnetizations. The magnetic tape media was fabricated using an actual production line and showed a very sharp signal response and a remarkably high signal‐to‐noise ratio compared to the currently used magnetic tape. 相似文献
109.
The synthesis of a series of stereochemically defined spirocyclic compounds and their use as novel P2-ligands for HIV-1 protease inhibitors are described. The bicyclic core of the ligands was synthesized by an efficient nBu 3SnH-promoted radical cyclization of a 1,6-enyne followed by oxidative cleavage. Structure-based design, synthesis of ligands, and biological evaluations of the resulting inhibitors are reported. 相似文献
110.