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排序方式: 共有926条查询结果,搜索用时 31 毫秒
901.
Nishimura S Li Z Watanabe H Yoshinaga K Sumikama T Tachibana T Yamaguchi K Kurata-Nishimura M Lorusso G Miyashita Y Odahara A Baba H Berryman JS Blasi N Bracco A Camera F Chiba J Doornenbal P Go S Hashimoto T Hayakawa S Hinke C Ideguchi E Isobe T Ito Y Jenkins DG Kawada Y Kobayashi N Kondo Y Krücken R Kubono S Nakano T Ong HJ Ota S Podolyák Z Sakurai H Scheit H Steiger K Steppenbeck D Sugimoto K Takano S Takashima A Tajiri K Teranishi T Wakabayashi Y Walker PM Wieland O Yamaguchi H 《Physical review letters》2011,106(5):052502
The β-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of β decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted. 相似文献
902.
Tachibana H 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2011,87(3):66-80
Green tea polyphenols have emerged over the past two decades as an important dietary factor for health promotion. There is considerable evidence that tea polyphenols, in particular (-)-epigallocatechin-3-gallate (EGCG) inhibit carcinogenesis. However, the mechanisms for the cancer-preventive activity of EGCG are not completely characterized and many features remain to be elucidated. Recently we have identified a cell-surface EGCG receptor and the relating molecules that confer EGCG responsiveness to many cancer cells at physiological concentrations. Here, we review some of the reported mechanisms for the cancer chemopreventive action of EGCG and provide an overview of several molecules that sense and manage the physiological functions of EGCG. 相似文献
903.
904.
Heng Wang Shun Hamanaka Prof. Toshihiko Yokoyama Dr. Hirofumi Yoshikawa Prof. Kunio Awaga 《化学:亚洲杂志》2011,6(4):1074-1079
In situ X‐ray absorption fine structure (XAFS) analyses were performed on rechargeable molecular cluster batteries (MCBs), which were formed by a lithium anode and cathode‐active material, [Mn12O12(CH3CH2C(CH3)2COO)16(H2O)4] with tert‐pentyl carboxylate ligand (abbreviated as Mn12tPe), and with eight Mn3+ and four Mn4+ centers. This mixed valence cluster compound is used in an effort to develop a reusable in situ battery cell that is suitable for such long‐term performance tests. The Mn12tPe MCBs exhibit a large capacity of approximately 210 Ah kg−1 in the voltage range V=4.0–2.0 V. The X‐ray absorption near‐edge structure (XANES) spectra exhibit a systematic change during the charging/discharging with an isosbestic point at 6555 eV, which strongly suggests that only either the Mn3+ or Mn4+ ions in the Mn12 skeleton are involved in this battery reaction. The averaged manganese valence, determined from the absorption‐edge energy, decreased monotonically from 3.3 to 2.5 in the first half of the discharging (4.0>V>2.8 V), but changed little in the second half (2.8>V>2.0 V). The former valence change indicates a reduction of the initial [Mn12]0 state by approximately ten electrons, which corresponds well with the half value of the observed capacity. Therefore, the large capacity of the Mn12 MCBs can be understood as being due to a combination of the redox change of the manganese ions and presumably a capacitance effect. The extended X‐ray absorption fine structure (EXAFS) indicates a gradual increase of the Mn2+ sites in the first half of the discharging, which is consistent with the XANES spectra. It can be concluded that the Mn12tPe MCBs would include a solid‐state electrochemical reaction, mainly between the neutral state [Mn12]0 and the super‐reduced state [Mn12]8− that is obtained by a local reduction of the eight Mn3+ ions in Mn12 toward Mn2+ ions. 相似文献
905.
Ghrelin is a stomach-derived peptide discovered as a ligand of the orphan G-protein coupled receptor. Ghrelin is now recognized as a major orexigenic neuropeptide. Immunohistochemical studies demonstrated that centrally administered ghrelin induced c-fos protein expression in many areas in the brain. Indeed, centrally administered ghrelin has various effects such as stimulating feeding, arousal, increasing gastric acid secretion, release of hormones from the pituitary, and inhibition of water intake. In particular, we recently showed that ghrelin was an antidipsogenic peptide with a simultaneous orexigenic effect. This may be of important, because most spontaneous daily water intake is temporally associated with feeding. Here, we summarise recent findings on the integration of central effects of ghrelin that regulate feeding, release hormones from the pituitary and inhibit fluid/water intake. 相似文献
906.
907.
Hajime Kobori Atsushi Sekiya Nobuhiro Yasuda Keiichi Noguchi Tomohiro Suzuki Jae-Hoon Choi Hirofumi Hirai Hirokazu Kawagishi 《Tetrahedron letters》2013
Three novel compounds were isolated from the culture broth of Armillaria sp. Their structures were elucidated mainly by spectroscopic data analyses. All the compounds regulated hypocotyl and root growth of lettuce. 相似文献
908.
Yuji Fujitsu Hirofumi Nakayama Tetsuya Uchida Shinichi Yamazaki Kunio Kimura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(4):780-785
Hollow spheres of aromatic polyamide are obtained by the reaction‐induced phase separation during polymerization of 5‐hydroxyisophthalic acid and 1,4‐phenylene diamine in an aromatic solvent at a concentration of 1–2% at 320 °C without stirring. The hollow sphere has a dimple hole and the diameters of the hollow spheres are 3–4 μm. The droplets are initially generated via liquid–liquid phase separation and then rigid cross‐linked network structure formed the rigid skin layer on the surface of the droplets. The solidification of the droplets occurred owing to the further polymerization in them with maintaining the morphology to form the hollow spheres. The hollow spheres exhibit outstanding thermal stability. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
909.
Egawa T Watanabe H Fujimura T Ishida Y Yamato M Masui D Shimada T Tachibana H Yoshida H Inoue H Takagi S 《Langmuir : the ACS journal of surfaces and colloids》2011,27(17):10722-10729
Saponite-type clays that have different cation exchange capacities were successfully synthesized by hydrothermal synthesis. The structure and properties were analyzed by X-ray diffraction, X-ray fluorescence, (27)Al NMR, FT-IR, thermogravimetric and differential thermal analysis, atomic force microscopy, and cation exchange capacity measurement. The intercharge distances on the synthetic saponite (SS) surfaces were calculated to be 0.8-1.9 nm on the basis of a hexagonal array. The complex formation behavior between SS and cationic porphyrins was examined. It turns out that the average intermolecular distance between porphyrin molecules on the SS surface can be controlled, depending on the charge density of the SS. In the case of tetrakis(1-methylpyridinium-4-yl)porphyrin (H(2)TMPyP(4+)), the average intermolecular distances on the SS surface can be controlled from 2.3 to 3.0 nm on the basis of a hexagonal array. It was also found that absorption maxima of porphyrins depend on the charge density of the SS. The adsorption behavior of porphyrin on the SS surface can be rationally understood by the previously reported "size-matching rule". This methodology using host-guest interaction can realize a unique adsorption structure control of the porphyrin molecule on the SS surface, where the gap distance between guest porphyrin molecules is rather large. These findings will be highly valuable to construct photochemical reaction systems such as energy transfer in the complexes. 相似文献
910.