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71.
72.
Kobayashi T Nakanishi H Nishizawa NK 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(9):900-913
Higher plants utilize various mechanisms to maintain iron homeostasis. To acquire sparingly soluble iron from the rhizosphere, graminaceous plants synthesize natural iron (III) chelators known as mugineic acid family phytosiderophores (MAs). Recent research has uncovered various genes involved in iron uptake and translocation, as well as factors regulating the expression of these genes, especially in rice. Manipulation of these molecular components is used to produce transgenic crops with enhanced tolerance to iron deficiency, or with a high seed iron content. Since iron homeostasis is closely linked to that of other mineral elements, an understanding of this phenomenon will serve as the basis for the production of crops with low concentrations of toxic metals and transgenic plants for phytoremediation. 相似文献
73.
Takoukam Soh Serge Didier Shinji Tokonami Masahiro Hosoda Takahito Suzuki Hiromi Kudo 《Isotopes in environmental and health studies》2013,49(5):499-510
ABSTRACTRadon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon–thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31?±?1 to 436?±?12 Bq?m–3, 4?±?7 to 246?±?5 Bq?m–3, and 1.5?±?0.9 to 13.1?±?9.4 Bq?m–3. The mean value of the equilibrium factor for thoron is estimated at 0.11?±?0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9?mSv?a–1 with an average value of 2.6?±?0.1?mSv?a–1. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9?mSv?a–1 with an average value of 1.0?±?0.4?mSv?a–1. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60?% with an average value of 26?%; thus their contributions should not be neglected in the inhalation dose assessment. 相似文献
74.
Two new norsesterterpenoid cyclic peroxides, trunculins X and Y, were isolated from an Okinawan sponge Sigmosceptrella sp. Their structures were determined by spectroscopic analyses on intact molecules and derivatives and also by crystallographic study. The compounds showed cytotoxicity in a range of IC50 0.32–20 μM against three cell lines. 相似文献
75.
Kyosuke Doi Yuki Yamada Masaki Okoshi Junichi Ono Chien‐Pin Chou Hiromi Nakai Atsuo Yamada 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(24):8108-8112
Alkaline metals are an ideal negative electrode for rechargeable batteries. Forming a fluorine‐rich interphase by a fluorinated electrolyte is recognized as key to utilizing lithium metal electrodes, and the same strategy is being applied to sodium metal electrodes. However, their reversible plating/stripping reactions have yet to be achieved. Herein, we report a contrary concept of fluorine‐free electrolytes for sodium metal batteries. A sodium tetraphenylborate/monoglyme electrolyte enables reversible sodium plating/stripping at an average Coulombic efficiency of 99.85 % over 300 cycles. Importantly, the interphase is composed mainly of carbon, oxygen, and sodium elements with a negligible presence of fluorine, but it has both high stability and extremely low resistance. This work suggests a new direction for stabilizing sodium metal electrodes via fluorine‐free interphases. 相似文献
76.
Dr. Hiromi Oshita Takashi Suzuki Kyohei Kawashima Prof. Dr. Hitoshi Abe Prof. Dr. Fumito Tani Prof. Dr. Seiji Mori Prof. Dr. Tatsuo Yajima Prof. Dr. Yuichi Shimazaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(32):7649-7658
In order to gain new insights into the effect of the π–π stacking interaction of the indole ring with the CuII–phenoxyl radical as seen in the active form of galactose oxidase, we have prepared a CuII complex of a methoxy-substituted salen-type ligand, containing a pendent indole ring on the dinitrogen chelate backbone, and characterized its one-electron-oxidized forms. The X-ray crystal structures of the oxidized CuII complex exhibited the π–π stacking interaction of the indole ring mainly with one of the two phenolate moieties. The phenolate moiety in close contact with the indole moiety showed the characteristic phenoxyl radical structural features, indicating that the indole ring favors the π–π stacking interaction with the phenoxyl radical. The UV/Vis/NIR spectra of the oxidized CuII complex with the pendent indole ring was significantly different from those of the complex without the side-chain indole ring, and the absorption and CD spectra exhibited a solvent dependence, which is in line with the phenoxyl radical–indole stacking interaction in solution. The other physicochemical results and theoretical calculations strongly support that the indole ring, as an electron donor, stabilizes the phenoxyl radical by the π–π stacking interaction. 相似文献
77.
78.
Takashi Yoshimoto Prof. Dr. Hisako Hashimoto Dr. Nozomi Takagi Prof. Dr. Shigeyoshi Sakaki Naoki Hayakawa Dr. Tsukasa Matsuo Prof. Dr. Hiromi Tobita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3795-3798
A tungsten silylyne complex having a W≡Si triple bond reacted with two molecules of aldehydes at room temperature to give W−Si−O−C four-membered metallacycles by [2+2] cycloaddition and subsequent formyl hydrogen transfer from one aldehyde molecule to another. Upon heating to 70 °C, the four-membered metallacycles underwent metathesis-like fragmentation cleanly to afford carbyne complexes and “silanoic esters,” in a manner similar to that of metallacyclobutadiene, an intermediate of alkyne metathesis reactions, and dimerization of the latter products gave 1,3-cyclodisiloxanes. The “silanoic ester” was also trapped by pivalaldehyde to give a [2+2] cycloaddition product in high yield. 相似文献
79.
80.
Hiromi Yamashita Kohsuke Mori Sayoko Shironita Yu Horiuchi 《Catalysis Surveys from Asia》2008,12(2):88-100
The isolated and tetrahedrally coordinated metal oxide (Ti, V, Cr, Mo and W-oxides) moieties can be included in the silica
matrixes of silica-based microporous zeolite and mesoporous silica materials and named as “single-site photocatalysts”. Under
UV-light irradiation these single-site photocatalysts form the charge transfer excited state, i.e., the excited electron–hole
pair state which is located quite near to each other in different from the manner observed on semiconducting materials such
as TiO2, and play a significant role in various photocatalytic reactions. These single-site photocatalysts not only can promote photocatalytic
reactions but also can be utilized to synthesis of functional materials. The nano-sized metal catalyst and visible-light sensitive
binary oxide photocatalyst can be synthesized on the excited single-site photocatalyst under UV-light irradiation. The transparent
mesoporous silica thin film with single-site photocatalyst generates the super-hydrophilic surface. In this review, our recent
applications of single-site photocatalysts to synthesis of the surface functional materials have been introduced. 相似文献