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91.
参数共振微扰法是一种简单的非反馈混沌控制方法,它十分适合非自治系统的混沌控制.研究了这种方法在电流模式控制Boost变换器混沌控制中的应用,并通过对扰动相位进行优化 ,达到最优的混沌控制结果.同时对参数共振微扰法及其优化方法在Boost变换器混沌控制中的作用进行了理论分析,推导并计算了各种电路参数变化对有效的混沌控制所需的扰动的影响.
关键词:
Boost变换器
混沌
混沌控制
参数共振微扰法 相似文献
92.
Energy landscape of a peptide, extracted from a distal beta-hairpin of src SH3 domain, in explicit water was obtained with the multicanonical molecular dynamics. A variety of beta-hairpins with various strand-strand hydrogen bonds were found in the energy landscape at 300 K. There was no energy barrier between random-coil and hairpins. Thus, the peptide conformation can easily change from the random-coil to the hairpins in the thermal fluctuations at 300 K. The landscape also included two clusters of alpha-helices, among which an energy barrier existed, and besides, these helix clusters were separated from the other conformations. Thus, the free-energy barrier exists among the helices and the other conformations. Intermediate clusters were found between the helix and the hairpin clusters. The current study showed that the isolated state of this peptide in water fluctuates among random-coil, beta-hairpin, and alpha-helix. In SH3 domain, which has a topology of mainly beta-protein, the whole-protein folding may proceed when the segment is folded in the beta-hairpin and the other parts of the protein are coupled with the beta-hairpin in an energetically or kinetically favorite way. 相似文献
93.
Junichi Higo Mariko Yamaki Michiru Hogyoku Takuya Takahashi Shigeru Endo Kuniaki Nagayama 《Journal of computational chemistry》1994,15(11):1278-1290
Two-dimensional protein (ferritin) aggregates with a square lattice symmetry, which were formed within a thin liquid layer on a mercury surface, were studied by molecular dynamics (MD) simulation. For the simulation, the ferritin molecule was modeled by an assembly of 49 spheres, and the intermolecular interactions were given by simple formulae. During the simulation, molecules were confined within a layer, which corresponds to the thin liquid layer. An annealing MD simulation was done starting from a random molecular configuration within the layer, and aggregates with the square lattice symmetry were also obtained. To study the stability of aggregates, dissociation processes of the aggregates were analyzed using MD simulations at room temperature. Interactions between the nearest-neighbor molecules were regarded as bonds. Mean bond energies and correlation coefficients between the bond energies were calculated from the MD trajectories. A decay profile according to the dissociation was obtained, yielding a dissociation rate constant. Buried bonds were stronger than peripheral bonds. The larger the aggregate size, the stronger the bond for each of the buried and peripheral bonds. A simple theoretical account, which is applicable to a general bonded network, was introduced to analyze the dynamics of the aggregates. © 1994 by John Wiley & Sons, Inc. 相似文献
94.
Yuzuru Sanemitsu Akio Manabe Shinichi Kawamura Junichi Satoh Yoo Tanabe 《Journal of heterocyclic chemistry》1990,27(5):1517-1518
2-Alkylamino-4H-1,3,4-benzothiadiazines 3 are prepared in a one-pot synthesis from 1-phenyl-3-thiosemi-carbazides 1 and bromine through an oxidative cyclization. 相似文献
95.
Sakurai R Suzuki S Hashimoto J Baba M Itoh O Uchida A Hattori T Miyano S Yamaura M 《Organic letters》2004,6(13):2241-2244
[reaction: see text] A diastereomeric mixture of the alpha-amino nitrile prepared by the Strecker reaction of benzaldehyde, (1S,2R)-1-aminoindan-2-ol, and cyanotrimethylsilane thermally epimerizes in the solid state to give a single diastereomer with an (S)-configuration at the alpha position to the nitrile moiety. This shows a sharp contrast to the reaction conducted in DMSO at room temperature, which gives a 1:1 mixture of (S)- and (R)-isomers. Several other alpha-amino nitriles also epimerize in the solid-state toward single diastereomers. 相似文献
96.
The alkylation of the sodium salt of the malonic acid diester with (R)-1-(2-pyridinyl)ethyl methanesulfonate (2) gave the dimethyl (R)-[1-(2-pyridinyl)ethyl]malonate (3a), stereospecifically. The alkylation reaction of methyl acetoacetate gave the methyl (2'S,2R/2S)-3-oxo-2-[1-(2-pyridinyl)ethyl]butanoate (3d) along with the methyl (S)-3-[1-(2-pyridinyl)ethoxy]-2-butenoate (4d). The acid hydrolysis and decarboxylation of 3d under acidic conditions gave (R)-4-(2-pyridinyl)pentan-2-one (6), and the alkylation of methyl (R)-[1-(2-pyridinyl)ethyl]acetoacetate with benzyl bromide gave a mixture of C-benzylated and O-benzylated products 7 and 8. 相似文献
97.
A convenient synthesis of new heterocycles such as 7,8-dihydro-1H-imidazo[2,1-i]purin-5(4H)-ones ( 2 , n = 0) and 5,6-dihydro-1H-imidazo[2,1-b]purin-9(8H)-ones ( 3 ) was described. The syntheses of 2 and 3 were accomplished by treatment of 6-methylthio-7H-purin-2(3-H)-ones 7 or 2-benzylthio-1-methyl-9-triphenylmethyl-9H-purin-6(1H)-one ( 15 ) with appropriate aminoalcohol followed by dehydrative cyclization using thionyl chloride. Compound 15 was efficiently prepared by benzylation of 6-hydroxy-2-mercaptopurine ( 12 ) followed by tritylation and N-methylation. 相似文献
98.
Takeshi Shimizu Junichi KusakaHaruaki Ishiyama Tadashi Nakata 《Tetrahedron letters》2003,44(27):4965-4968
The 6,6-spiroacetal segment of spirofungin A, an antifungal antibiotic isolated from Streptomyces violaceusniger Tü 4113, was efficiently prepared via the coupling reaction of the Weinreb amide and the alkyne which are readily available from the common intermediate. The synthesis includes the unsymmetrization through a stereoinversion at the C11 position and the transacetalization as the key steps. 相似文献
99.
Marine toxins targeting the actin cytoskeleton represent a new and promising class of anti-cancer compounds. Here we present a 2.0 A resolution structure of swinholide A, a marine macrolide, bound to two actin molecules. The structure demonstrates that the actin dimer in the complex does not represent a physiologically relevant entity, for the two actin molecules do not interact with each other. The swinholide A actin binding site is the same as that targeted by toxins of the trisoxazole family and numerous actin binding proteins, highlighting the importance of this site in actin polymerization. The observed structure reveals the mechanism of action of swinholide A and provides a structural framework about which to design new agents directed at the cytoskeleton. 相似文献
100.
Junichi Shiina 《Tetrahedron letters》2005,46(45):7683-7686
The first total synthesis of acutifolone A, a sesquiterpenoid carrying the bicyclo[4.3.0]nonane structure 1, was successfully achieved from the intermediate 6 produced by the intramolecular Diels-Alder reaction. 相似文献