全文获取类型
收费全文 | 887篇 |
免费 | 36篇 |
国内免费 | 4篇 |
专业分类
化学 | 720篇 |
晶体学 | 7篇 |
力学 | 20篇 |
数学 | 44篇 |
物理学 | 136篇 |
出版年
2023年 | 12篇 |
2022年 | 9篇 |
2021年 | 7篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 24篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 43篇 |
2012年 | 57篇 |
2011年 | 54篇 |
2010年 | 43篇 |
2009年 | 31篇 |
2008年 | 51篇 |
2007年 | 76篇 |
2006年 | 65篇 |
2005年 | 39篇 |
2004年 | 61篇 |
2003年 | 42篇 |
2002年 | 35篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 3篇 |
1985年 | 14篇 |
1984年 | 18篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1972年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有927条查询结果,搜索用时 15 毫秒
151.
Eiji Kamio Aiko Kato Satoshi Yonemura Tsutomu Ono Hidekazu Yoshizawa 《Colloid and polymer science》2008,286(6-7):787-793
Monodisperse polymelamine microcapsules were prepared by phase separation method. Control of microcapsule diameter was investigated using the uniform-sized oil-in-water emulsion droplets as the capsule core. The monodisperse emulsion droplets were prepared using the Shirasu porous glass (SPG) membrane emulsification technique. The effects of the diameter of the oil droplet and concentration of sodium dodecyl sulfate (SDS), which is a typical emulsifier in SPG membrane emulsification, on microencapsulation were investigated. The microcapsules were aggregated when oil droplets with small size were microencapsulated at high SDS concentration. To reduce the SDS concentration, the creamed emulsion was used. The monodisperse polymelamine microcapsules were successfully prepared by using the creamed emulsion. The microcapsule diameter was almost similar to the diameter of the encapsulated oil droplet. The coefficient of variation values was about 10% for all microcapsules prepared in this study. Control of microcapsule diameter was achieved in the range of 5–60 μm. 相似文献
152.
We attempted to develop a new type titania photocatalyst that, when activated, responded in not only the ultraviolet rays
region but also visible light radiation region by the new titania photocatalyst with the zirconia and nitrogen simultaneously
introduced in the titania lattice. The decomposition performance of the standard organic compound in water by this new type
titania photocatalyst nanoparticle was compared with the conventional type under both the ultraviolet ray and visible light
radiation conditions. It was suggested that the low-molecular-weight organic compounds were also generated from the organic
compound in water by the new type titania photocatalyst activities under the visible light radiation. 相似文献
153.
Oxidative Annulation of Arenecarboxylic and Acrylic Acids with Alkynes under Ambient Conditions Catalyzed by an Electron‐Deficient Rhodium(III) Complex
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Eiji Kudo Dr. Yu Shibata Mutsumi Yamazaki Koji Masutomi Dr. Yuta Miyauchi Miho Fukui Haruki Sugiyama Prof. Dr. Hidehiro Uekusa Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14190-14194
It has been established that an electron‐deficient CpE rhodium(III) complex catalyzes the oxidative [4+2] annulation of substituted arenecarboxylic and acrylic acids with alkynes under ambient conditions (at RT–40 °C, under air) without using excess amounts of substrates to produce the corresponding substituted isocoumarins and α‐pyrones in high yields. Minor modification of reaction conditions depending on the coordination ability of alkynes realized the high efficiency. 相似文献
154.
Magnetically and Near‐Infrared Light‐Powered Supramolecular Nanotransporters for the Remote Control of Enzymatic Reactions
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)
Dr. Svetlana A. Chechetka Dr. Eiji Yuba Prof. Kenji Kono Dr. Masako Yudasaka Dr. Alberto Bianco Dr. Eijiro Miyako 《Angewandte Chemie (International ed. in English)》2016,55(22):6476-6481
Cancer is one of the primary causes of death worldwide. A high‐precision analysis of biomolecular behaviors in cancer cells at the single‐cell level and more effective cancer therapies are urgently required. Here, we describe the development of a magnetically‐ and near infrared light‐triggered optical control method, based on nanorobotics, for the analyses of cellular functions. A new type of nanotransporters, composed of magnetic iron nanoparticles, carbon nanohorns, and liposomes, was synthesized for the spatiotemporal control of cellular functions in cells and mice. Our technology will help to create a new state‐of‐the‐art tool for the comprehensive analysis of “real” biological molecular information at the single‐cell level, and it may also help in the development of innovative cancer therapies. 相似文献
155.
156.
Isobe M Onoda M Shizuya M Tanaka M Takayama-Muromachi E 《Journal of the American Chemical Society》2007,129(47):14585-14596
The incommensurate modulated crystal structure of the new misfit-layer calcium cobalt oxide (Ca0.85OH)2alphaCoO2 was investigated using a superspace-group formalism with synchrotron X-ray diffraction data. The compound is a kind of composite crystal that consists of two interpenetrating subsystems, [CoO2]infinity layers containing triangular lattices formed by edge-sharing CoO6 octahedra, separated from each other by [2Ca0.85OH]infinity double-layered rock-salt-type slabs. Both the subsystems are monoclinic lattices with the unit cell parameters, a1 = 2.8180(4) A, b = 4.8938(6) A, c = 8.810(1) A, alpha0 = 95.75(3) degrees , and alpha(=|q|=a1/a2) = 0.57822(8), viz., a2 = 4.8736 A, with Z = 2. A possible superspace group is C2/m(alpha10)s0-C21/m(alpha(-1)10) for the respective subsystems. The atomic positions deviate from the average positions of the fundamental structure due to the incommensurable periodic interaction between the subsystems. A significant structural modulation was found in the [2Ca0.85OH] subsystem, whereas the modulation in the [CoO2] subsystem is less than in [2Ca0.85OH], due to the tight bonding of the close-packed CoO6 octahedra. The degree of modulation in the CoO2 layers, i.e., the potential modulation, is almost the same as those of other compounds of the misfit-layer cobalt oxides. Flattened CoO6 octahedra indicate hole doping into the CoO2 layers. The [2Ca0.85OH] blocks act as the charge reservoir layers, and the defect Ca ions are presumably the source of the holes. 相似文献
157.
We report on the oligosaccharide recognition through noncovalent interactions in water based on a unique supramolecular homoduplex-to-heteroduplex transformation of the oligoresorcinol nonamer as a fully artificial receptor. The oligoresorcinol forms a double helix in water, which unravels and entwines upon complexation with specific oligosaccharides with a particular chain length and glucosidic linkage pattern, thus generating the heteroduplex with an excess one-handed helical conformation that can be readily monitored and further quantified by absorption, circular dichroism, and NMR spectroscopies. 相似文献
158.
An optically active helical poly(phenylacetylene) was synthesized by the copolymerization of phenylacetylenes bearing optically active hydroxy or ester groups obtained by the kinetic resolution of a racemic phenylacetylene with lipase; the helix-sense was inverted from one helix to another by the further chemical modification of the hydroxy groups with achiral bulky isocyanates or an acid chloride. 相似文献
159.
Specific isolation of N-terminal fragments from proteins and their high-fidelity de novo sequencing 总被引:1,自引:0,他引:1
Yamaguchi M Obama T Kuyama H Nakayama D Ando E Okamura TA Ueyama N Nakazawa T Norioka S Nishimura O Tsunasawa S 《Rapid communications in mass spectrometry : RCM》2007,21(20):3329-3336
A new method to determine N-terminal amino acid sequences of multiple proteins at low pmol level by a parallel processing has been developed. The method contains the following five steps: (1) reduction, S-alkylation and guanidination for targeted proteins; (2) coupling with sulfosucccimidyl-2-(biotinamido)ethyl-1,3-dithiopropionate(sulfo-NHS-SS-biotin) to N(alpha)-amino groups of proteins; (3) digestion of the modified proteins by an appropriate protease; (4) specific isolation of N-terminal fragments of proteins by affinity capture using the biotin-avidin system; (5) de novo sequence analysis of peptides by MALDI-TOF-/MALDI-TOF-PSD mass spectrometry with effective utilization of the CAF (chemically assisted fragmentation) method.1 This method is also effective for N-terminal sequencing of each protein in a mixture of several proteins, and for sequencing components of a multiprotein complex. It is expected to become an essential proteomics tool for identifying proteins, especially when used in combination with a C-terminal sequencing method. 相似文献
160.
Ito A Okamura TA Yamamoto H Ueyama N Yamaguchi M Kuyama H Ando E Tsunasawa S Ake K Masui R Kuramitsu S Nakazawa T Norioka S 《Rapid communications in mass spectrometry : RCM》2007,21(16):2647-2653
Use of a bis(terpyridine)ruthenium(II) derivative as an N-terminal labeling reagent resulted in the simultaneous detection and individual determination of all the N-terminal fragments of the proteins in a mixture without requiring any separation. All of the N-termini of the guanidinated proteins were labeled selectively by the ruthenium complex (-CO-labeling). After chymotryptic digestion, the fragments were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and post-source decay (PSD). The -CO moiety exclusively enhanced N-terminal fragment ions in mass spectra and enabled easy N-terminal sequencing. In a mixture containing three different proteins (lysozyme, ubiquitin, and insulin), all of the N-terminal fragment ions labeled with the ruthenium complex were found to produce uniformly intense peaks without the detection of the other unlabeled fragments. The N-terminal sequences of these ions were determined individually by PSD analysis. Application to unknown proteins from Thermus thermophilus HB8 with two-dimensional electrophoretic separation resulted in the successful determination of the N-terminal sequence and easy identification of the target protein. 相似文献