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161.
Tomohiro Terada Hirofumi Simada Hideharu Ishida Makoto Kiso Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(4-5):519-534
Abstract KDN-Lex ganglioside analogs (10, 13, 16 and 19) containing the modified reducing terminal and L-rhamnose in place of L-fucose have been synthesized. Glycosidation of methyl 2,3,4-tri-O-benzyl-1-thio-α-L-rhamnopyranoside (1) with 2-(trimethylsilyl)ethyl O-(2-acetamido-4,6-O-benzylidene-2-deoxy-β-D-glucopyranosyl)-(1→3)-O-(2,4,6-tri-O-benzyl-α-D-galacopyranoside (2), followed by reductive ring opening of the benzylidene acetal, gave 2-(trimethylsilyl)ethyl O-(2,3,4-tri-O-benzyl-α-L-rhamnopyranosyl)-(1→3)-O-(2-acet-amido-6-O-benzyl-2-deoxy-β-D-glucopyranosyl)-(1→3)-O-(2,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (4). The tetrasaccharide 4 was coupled with methyl O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-2,4,6-tri-O-benzoyl-1-thio-β-D-galactopyranoside(5), using dimethyl(methylthio)sulfonium triflate (DMTST), to give the hexasaccharide 6, which was converted into compound 11 in the usual manner. Compounds 8 and 11 were transformed, via bromination of the reducing terminal, radical reduction, O-deacylation and saponification of the methyl ester, into the desired KDN-Lex hexasaccharides (10, 13). On the other hand, glycosylation of 2-(tetradecyl)hexadecanol with α-trichloroacetimidates 14 and 17, afforded the target ganglioside analogs 16 and 19. 相似文献
162.
163.
164.
Inside Cover: Inhibition of Heme Uptake in Pseudomonas aeruginosa by its Hemophore (HasAp) Bound to Synthetic Metal Complexes (Angew. Chem. Int. Ed. 11/2014)
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165.
A multiscale simulation method, "multiscale essential sampling (MSES)," is proposed for calculating free energy surface of proteins in a sizable dimensional space with good scalability. In MSES, the configurational sampling of a full-dimensional model is enhanced by coupling with the accelerated dynamics of the essential degrees of freedom. Applying the Hamiltonian exchange method to MSES can remove the biasing potential from the coupling term, deriving the free energy surface of the essential degrees of freedom. The form of the coupling term ensures good scalability in the Hamiltonian exchange. As a test application, the free energy surface of the folding process of a miniprotein, chignolin, was calculated in the continuum solvent model. Results agreed with the free energy surface derived from the multicanonical simulation. Significantly improved scalability with the MSES method was clearly shown in the free energy calculation of chignolin in explicit solvent, which was achieved without increasing the number of replicas in the Hamiltonian exchange. 相似文献
166.
Ikuo YAMASHINA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(6):578-587
This review describes the results of the author’s studies on glycoproteins which have been carried out for more than 50 years. Starting from the elucidation of basic structures of glycoproteins, i.e. the structure of the linkage between an amino acid and a sugar and the occurrence of the β-mannosidic linkage as the common structure of glycoproteins, the author became interested in the cell membrane glycoproteins focused on the comparison of cancer cells versus normal cells. These studies were then extended to the establishment of sugar-directed and cancer-associated monoclonal antibodies. Some of the monoclonal antibodies are useful for cancer diagnosis. 相似文献
167.
K. Kikunaga T. Yamamoto Y. Tanaka N. Kikuchi K. Tokiwa T. Watanabe N. Terada 《Physica C: Superconductivity and its Applications》2010,470(21):1916-1919
(Cu, C)–Ba–O thin films have been deposited at low growth temperature of 450–570 °C by pulsed laser deposition method. A control of CO2 gas pressure and the growth temperature, usage of BaCuyOx pellet target resulted in an expansion of twice c-axis length of BaCuO2 structure (2c phase) and a significant rise of conductivity. Measurements of in-situ XPS suggest that the 2c phase should be (Cu, C)Ba2CuOx [(Cu, C)-1201]. The maximum temperature of onset of the superconducting transition and zero resistance state obtained so far were 60 and 47 K, respectively. 相似文献
168.
K. Kikunaga T. Yamamoto Y. Tanaka N. Kikuchi K. Tokiwa T. Watanabe N. Terada 《Physica C: Superconductivity and its Applications》2010,470(17-18):678-681
Transport properties of (Cu, C)Ba2CuOx [(Cu, C)-1201] thin films have been characterized by in situ temperature dependence of resistivity, without breaking vacuum from the deposition to the measurement. In in situ transport properties measurements, the obtained results reveal that (Cu, C)Ba2CuOx films exhibit Tc > 20 K on the cased of conductivity at 290 K (σ[290 K]) > 4 × 102 S/cm and temperature coefficient of resistivity (TCR) > 1.5 × 10?3 K?1, and doping level of them should be in between under-doped and optimally-doped states. Their results suggest that there would be possible to further increases of Tc, and XPS data suggest that (Cu, C)-system should have the excellent dopability in their charge reservoir and the possibility of low anisotropy. 相似文献
169.
Masaki Oba Yoichiro Maruyama Katsuaki Akaoka Masabumi Miyabe Ikuo Wakaida 《Applied Physics A: Materials Science & Processing》2010,101(3):545-549
Emission characteristics of gadolinium (Gd) oxide are studied, using ns and fs laser pulses for ablation in double-pulse laser
induced breakdown spectroscopy (LIBS). In the current conditions of pulse energy and signal detection timing, emission intensity
enhancement in the reheating mode is 25-fold, but little effect can be observed in a pre-pulse mode. It is shown that the
optimum focus position of the ablation pulse is about 5 mm apart from the sample surface in the reheating mode. Although little
emission can be observed in the single-pulse configuration with fs ablation pulses, the intense emission can be observed in
the reheating mode in the double-pulse configuration. 相似文献
170.
The in vitro reactivities of astaxanthin and β-carotene toward peroxynitrite were investigated and the reaction products after scavenging with peroxynitrite were analyzed. A series of carotenoids substituted with nitro group, 14′-s-cis-15′-nitroastaxanthin, 10′-s-cis-11′-cis-11′-nitroastaxanthin, 14′-s-cis-15′-nitro-β-carotene and 10′-s-cis-11′-cis-11′-nitro-β-carotene, were isolated from the reaction products of carotenoids with peroxynitrite. Carotenoids with nitro derivatives were reported for the first time. These results indicated that astaxanthin and β-carotene could catch peroxynitrite or nitrogen dioxide radical (NO2) in their molecule to form nitrocarotenoids. 相似文献