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排序方式: 共有729条查询结果,搜索用时 62 毫秒
721.
Yamagami R Kobayashi K Saeki A Seki S Tagawa S 《Journal of the American Chemical Society》2006,128(7):2212-2213
We report the first direct observation of charge transport dynamics using time-resolved microwave conductivity and transient absorption spectroscopy techniques on the photolysis of an anthraquinone-bound DNA complex. 相似文献
722.
The adsorption of ovalbumin (OA) onto the bubble surfaces was studied with various pHs (3.5, 4.6, 6.0 and 8.0) by a continuous foam separation technique. From the value of the saturated surface density of adsorbed OA, the variation of effective diameter (D) of an OA molecule on the bubble surface was estimated for various pHs (3.5, 4.6, 6.0 and 8.0) of the OA solutions, assuming that the cross section of the OA molecules be circular and that the OA molecules adsorb on the bubble surface in a closest packing structure. The estimated variation of D with pH was attempted to explain based on a model modified from that proposed by Pujar and Zydney. The modified model could well reproduce the variation of the effective diameter with pH; the values of D calculated on the basis of the modified model almost agreed with that estimated from the saturated surface density in the present experimental pH range. From these, conclusion was drawn that the modified model presented in this study can express the variation in the effective diameter with pH. 相似文献
723.
In order to increase the adsorption capacities of bentonite, sepiolite, and illite for the removal of boron form aqueous solution, the clay samples were modified by nonylammonium chloride. Specific surface areas of the samples were determined as a result of N2 adsorption-desorption at 77 K using the BET method. X-ray powder diffraction analysis of the clays and modified clays was used to determine the effects of modifying agents on the layer structure of the clays. The surface characterization of clays and modified clay samples was conducted using the FTIR technique before and after the boron adsorption. For the optimization of the adsorption of boron on clays and modified clays, the effect of pH and ionic strength was examined. The results indicate that adsorption of boron can be achieved by regulating pH values in the range of 8-10 and high ionic strength. In order to find the adsorption characteristics, Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were applied to the adsorption data. The data were well described by Freundlich and Dubinin-Radushkevich adsorption isotherms while the fit of Langmuir equation to adsorption data was poor. It was reached that modification of bentonite and illite with nonylammonium chloride increased the adsorption capacity for boron sorption from aqueous solution. 相似文献
724.
725.
Tsuneo Imamoto Takeshi Yoshizawa Koutaro Hirose Yoshiyuki Wada Hideki Masuda Kentaro Yamaguchi Hiroko Seki 《Heteroatom Chemistry》1995,6(2):99-104
(SP)-9-Anthryl(l-menthyloxy)phenylphosphine-borane and (SP)-(1-l-menthyloxy)benzo[b]phosphole-borane were synthesized, and their structures were characterized by X-ray crystallographic analysis. The latter compound was reduced by lithium naphthalenide at −78°C with cleavage of the P O bond, and the subsequent reaction with electrophiles afforded the corresponding tertiary phosphine-boranes possessing good to excellent enantiomeric excesses. 相似文献
726.
727.
728.
Taito Hashimoto Dr. Ryusei Oketani Masaki Nobuoka Prof. Dr. Shu Seki Prof. Dr. Ichiro Hisaki 《Angewandte Chemie (International ed. in English)》2023,62(1):e202215836
Porous frameworks composed of non-stoichiometrically mixed multicomponent molecules attract much attention from a functional viewpoint. However, their designed preparation and precise structural characterization remain challenging. Herein, we demonstrate that cocrystallization of tetrakis(4-carboxyphenyl)hexahydropyrene and pyrene derivatives ( CP-Hp and CP-Py , respectively) yields non-stoichiometric mixed frameworks through networking via hydrogen bonding. The composition ratio of CP-Hp and CP-Py in the framework was determined by single crystalline X-ray crystallographic analysis, indicating that the mixed frameworks were formed over a wide range of composition ratios. Furthermore, microscopic Raman spectroscopy on the single crystal indicates that the components are not uniformly distributed such as ideal solid solution, but are done gradationally or inhomogeneously. 相似文献
729.
Lihua Lin Pongpen Kaewdee Vikas Nandal Ryota Shoji Hiroyuki Matsuzaki Kazuhiko Seki Mamiko Nakabayashi Naoya Shibata Xiaoping Tao Xizhuang Liang Yiwen Ma Takashi Hisatomi Tsuyoshi Takata Prof. Kazunari Domen 《Angewandte Chemie (International ed. in English)》2023,62(42):e202310607
Photocatalytic water splitting is an ideal means of producing hydrogen in a sustainable manner, and developing highly efficient photocatalysts is a vital aspect of realizing this process. The photocatalyst Y2Ti2O5S2 (YTOS) is capable of absorbing at wavelengths up to 650 nm and exhibits outstanding thermal and chemical durability compared with other oxysulfides. However, the photocatalytic performance of YTOS synthesized using the conventional solid-state reaction (SSR) process is limited owing to the large particle sizes and structural defects associated with this synthetic method. Herein, we report the synthesis of YTOS particles by a flux-assisted technique. The enhanced mass transfer efficiency in the flux significantly reduced the preparation time compared with the SSR method. In addition, the resulting YTOS showed improved photocatalytic H2 and O2 evolution activity when loaded with Rh and Co3O4 co-catalysts, respectively. These improvements are attributed to the reduced particle size and enhanced crystallinity of the material as well as the slower decay of photogenerated carriers on a nanosecond to sub-microsecond time range. Further optimization of this flux-assisted method together with suitable surface modification is expected to produce high-quality YTOS crystals with superior photocatalytic activity. 相似文献