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61.
Jack K. Clegg Dr. Simon S. Iremonger Dr. Michael J. Hayter Peter D. Southon Dr. René B. Macquart Dr. Martin B. Duriska Dr. Paul Jensen Dr. Peter Turner Dr. Katrina A. Jolliffe Prof. Cameron J. Kepert Prof. George V. Meehan Prof. Leonard F. Lindoy Prof. 《Angewandte Chemie (International ed. in English)》2010,49(6):1075-1078
62.
Rapireddy S Nhon L Meehan RE Franks J Stolz DB Tran D Selsted ME Ly DH 《Journal of the American Chemical Society》2012,134(9):4041-4044
Macrocyclic peptides with multiple disulfide cross-linkages, such as those produced by plants and those found in nonhuman primates, as components of the innate immunity, hold great promise for molecular therapy because of their broad biological activities and high chemical, thermal, and enzymatic stability. However, for some, because of their intricate spatial arrangement and elaborate interstrand cross-linkages, they are difficult to prepare de novo in large quantities and high purity, due to the nonselective nature of disulfide-bond formation. We show that the disulfide bridges of RTD-1, a member of the θ-defensin subfamily, could be replaced with noncovalent Watson-Crick hydrogen bonds without significantly affecting its biological activities. The work provides a general strategy for engineering conformationally rigid, cyclic peptides without the need for disulfide-bond reinforcement. 相似文献
63.
Yen Duong Joel Foisy Killian Meehan Leanne Merrill Lynea Snyder 《Discrete Mathematics》2012,312(12-13):2009-2022
We define a signed embedding of a signed graph into real projective space to be an embedding such that an embedded cycle is 0-homologous if and only if it is balanced. We characterize signed graphs that have a linkless signed embedding. In particular, we exhibit 46 graphs that form the complete minor-minimal set of signed graphs that contain a non-split link for every signed embedding. With one trivial exception, these graphs are derived from different signings of the seven Petersen family graphs. 相似文献
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Control of chaotic instability in a simplified model of a spinning spacecraft with dissipation is achieved using an algorithm derived using Lyapunov's second method. The control method is implemented on a realistic spacecraft parameter configuration which has been found to exhibit chaotic instability for a range of forcing amplitudes and frequencies when a sinusoidally varying torque is applied to the spacecraft. Such a torque, may arise in practice from an unbalanced rotor or from vibrations in appendages. Numerical simulations are performed and the results are studied by means of time history, phase space, Poincaré map, Lyapunov characteristic exponents and bifurcation diagrams. 相似文献
67.
Clegg JK Li F Jolliffe KA Meehan GV Lindoy LF 《Chemical communications (Cambridge, England)》2011,47(21):6042-6044
A large 4,4'-biphenylene-spaced bis-β-diketone ligand is demonstrated to form a neutral tetrahedral M(4)L(6) metal-organic cage that encloses a volume of 844 ?(3) and encapsulates four tetrahydrofuran guest molecules. 相似文献
68.
Jack K. Clegg Bianca Antonioli David J. Bray Karsten Gloe Kerstin Gloe Katrina A. Jolliffe Olga N. Kataeva George V. Meehan Marco Wenzel 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):319-329
4,4??-biphenylene spaced lipophilic bis-??-diketone ligands of the type 4,4??-bis(RC(O)CH2C(O))C12H8 (R = Pr, Ph, hexyl, octyl, nonyl) have been prepared and used for the liquid?Cliquid extraction of d-block metal ions. These ligands are expected to interact with divalent metal ions to form charge-neutral trinuclear metallocycles of type [M3(L 3 )3(solvent)] as has been demonstrated with the previously reported derivative of H2 L 3 (R = t Bu), the X-ray structure of which is reported. Liquid?Cliquid extraction studies were performed in a two-phase water/chloroform system employing a radiotracer technique for cobalt(II) and zinc(II). These experiments involved the systematic variation of ligand, metal and 4-ethylpyridine concentrations to probe the stoichiometries of the species extracted. Synergistic extraction was observed when 4-ethylpyridine was present with the ligand in the organic phase. Competitive extraction studies demonstrated the ligands are highly selective for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II). 相似文献
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JIANG Long-Guang ;YU Hai-Yang ;YUAN Cai ;WANG Jun-Dong ;CHEN Li-Qing ;Edward J. Meehan ;HUANG Zi-Xiang ;HUANG Ming-Dong 《结构化学》2009,28(11):1427-1432
Urokinase-type plasminogen activator (uPA) plays a crucial role in the regulation of plasminogen activation, tumor cell adhesion and migration. The inhibition of uPA activity is a promising mechanism for anti-cancer therapy. Most current uPA inhibitors employ a highly basic group (either amidine or guanidine group) to target the S1 pocket of uPA active site, which leads to poor oral bioavailability. Here we study the possibility of using less basic 2-aminobenzothiazole (ABT) as S1 pocket binding group. We report the crystal structures of uPA complexes with ABT or 2-amino-benzothiazole-6-carboxylic acid ethyl ester (ABTCE). The inhibitory constants of these two inhibitors were measured by a chromogenic competitive assay, and it was found that ABTCE is a better inhibitor for uPA (Ki = 656 μM) than ABT (Ki = 5.03 mM). This work shows that 2-amniobenzothiazole can be used as P1 group which may have better oral bioavailability than the commonly used amidine or guanidine group. We also found the ethyl ester group occupies the characteristic oxyanion hole and contacts to uPA 37- and 60-loops. Such work provides structural information for further improvements of potency and selectivity of this new class of uPA inhibitor. 相似文献