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排序方式: 共有283条查询结果,搜索用时 31 毫秒
61.
In this work, we report a novel dinuclear Sn (II) complex, [Sn2(Hpdm)2(H2O)6] 2H2O 2Cl ( 1 ) (H2pdm = pyridine‐2,6‐dimethanol), which has been crystallized out and characterized by elemental analysis, FTIR, 1H and 13C NMR, single crystal X‐ray studies and Density Functional Theory (DFT) analysis. X‐ray structure of 1 has confirmed it to be a dinuclear alkoxo‐bridged Sn (II) species where each metal adopts a seven coordinate distorted pentagonal bipyramidal (pbp) geometry. This is the first hepta‐coordinated Sn (II) complex ever isolated apart from already reported stannylenes. Spin density plots from DFT support the +2 oxidation state of each tin metal. Hirshfeld surface analysis reveals the presence of various H‐bonding interactions in the molecule and molecular docking results along with DFT confirm higher binding affinity of the present complex towards DNA. Moreover, the complex exhibits promising anticancer activities against HeLa and A549 cancer cell lines. 相似文献
62.
P. S. Pereira Silva Raza Murad Ghalib Sayed Hasan Mehdi Rokiah Hashim Othman Sulaiman Ali Jawad 《Journal of chemical crystallography》2010,40(12):1150-1154
Abstract
Cyclohexyl N-phenylcarbamate, C13H17NO2 (I), which is a useful target for biotransformations by fungi, has been synthesized and the structure has been solved by X-ray diffraction. The crystals are triclinic, space group P [`1] \bar{1} , with a = 5.2581 (2) ?, b = 9.5080 (3) ?, c = 12.6165 (4) ?, α = 70.544 (2)°, β = 89.075 (2)°, γ = 80.447 (2)°, M r = 219.28, V = 585.96 (3) ?3, Z = 2 and R = 0.065. In the title compound the phenyl ring makes a dihedral angle of 30.68(7)° with the carbamate group The molecules are linked into infinite chains via N–H···O hydrogen bonds along the a axis. These hydrogen-bonded chains are further linked by weaker C–H···π interactions. Quantum-mechanical ab initio calculations for the free molecule reproduce well the observed bond lengths and valency angles but show that the crystal packing might be responsible for the rotation of the phenyl ring out of the carbamate plane in the solid state conformation. 相似文献63.
Paola Marzullo Zlata Boiarska Helena Pérez-Peña Anne-Catherine Abel Beatriz Álvarez-Bernad Daniel Lucena-Agell Prof. Dr. Francesca Vasile Prof. Dr. Maurizio Sironi Prof. Dr. Karl-Heinz Altmann Dr. Andrea E. Prota J. Fernando Díaz Prof. Dr. Stefano Pieraccini Prof. Dr. Daniele Passarella 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103520
Maytansinol is a valuable precursor for the preparation of maytansine derivatives (known as maytansinoids). Inspired by the intriguing structure of the macrocycle and the success in targeted cancer therapy of the derivatives, we explored the maytansinol acylation reaction. As a result, we were able to obtain a series of derivatives with novel modifications of the maytansine scaffold. We characterized these molecules by docking studies, by a comprehensive biochemical evaluation, and by determination of their crystal structures in complex with tubulin. The results shed further light on the intriguing chemical behavior of maytansinoids and confirm the relevance of this peculiar scaffold in the scenario of tubulin binders. 相似文献
64.
This critical review covers synthetic ion channels and pores created between January 2004 and December 2005 comprehensively. The discussion of a rich collection of structural motifs may particularly appeal to organic, biological, supramolecular and polymer chemists. Functions addressed include ion selectivity and molecular recognition, as well as responsiveness to light, heat, voltage and membrane composition. The practical applications involved concern certain topics in medicinal chemistry (antibiotics, drug delivery), catalysis and sensing. An introduction to principles and methods is provided for the non-specialist; some new sources of inspiration from fields beyond chemistry are highlighted. 相似文献
65.
Raza A 《Chemical & pharmaceutical bulletin》2006,54(4):432-434
Study was carried out to develop two simple, fast, accurate and sensitive spectrophotometric methods (A and B) for the determination of citalopram hydrobromide in commercial tablet formulations. In method A, UV spectrophotometer determined the contents of citalopram hydrobromide in tablets at 240 nm in methanol solvent. The linear range was 5-40 microg ml-1 with molar absorptivity 1.4x10(4) l mol-1 cm-1. While the method B based on the reaction of citalopram base as n-electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone as pi-acceptors to give highly colored complex species that absorb maximally at 590 nm. Beer's law was obeyed in the concentration limit of 10-250 microg ml-1 with molar absorptivity 3.3x10(3) l mol-1 cm-1 for citalopram hydrobromide. The limits of detection and limit of quantification was calculated and found to be 5.2 microg ml-1 and 17.4 microg ml-1 respectively. The proposed methods were found to be rapid, accurate, precise and sensitive for the determination of citalopram hydrobromide in commercial tablet formulations with out interferences from common additives encountered. 相似文献
66.
67.
Farooq Umar Hossein Raza Hamdani Anwar‐ul‐Haque Sajid Raza Chaudhry Khalid Parvez 《国际流体数值方法杂志》2009,59(2):173-194
The effect of various reduced frequencies has been examined for an oscillating aspect ratio 10 NACA 0015 wing. An unsteady, compressible three‐dimensional (3D) Navier–Stokes code based on Beam and Warming algorithm with the Baldwin–Lomax turbulence model has been used. The code is validated for the study against published experimental data. The 3D unsteady flow field is simulated for reduced frequency values of 0.1, 0.2 and 0.3 for a fixed mean angle of attack position and fixed amplitude. The type of motion is sinusoidal harmonic. The force coefficients, pressure distributions and flow visualization show that at the given conditions the flow remains attached to the wing surface even at high angles of attack with no clear separation or typical light‐to‐deep category of dynamic stall. Increased magnitude of hysteresis and higher gradients are seen at higher reduced frequencies. The 3D effects are even found at midspan locations. In addition, the rate of decrease in lift near the wing tips compared with the wing root is not much like in the static cases. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
68.
69.
Zafar M. N. Nazar M. F. Raza M. A. Mughal E. U. Dalebrook A. F. Wright L. J. 《Russian Journal of General Chemistry》2017,87(3):554-563
Russian Journal of General Chemistry - Bis(pyridinium)amine 4,4'-[(2-aminophenyl)azanediyl]bis(1-methylpyridin-1-ium)triflate ([H2L][TfO]2) was synthesized and characterized by elemental... 相似文献
70.
F De Luca E De Vita G H Raza C Casieri 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,139(1):126-131
The transverse relaxation time in the rotating frame T2rho is proposed as an effective parameter to get specific contrast in solid state imaging. Several peculiarities make T2rho an interesting candidate to map dynamics and structure in solids: the effect of the secular spin interaction can be controlled by the experimenter and therefore the relaxation associated with the nonsecular terms, which is particularly sensitive to very slow dynamics, can be observed. In this paper we present preliminary results obtained on polymers and prove the capability of the MARF Imaging, enhanced by a filter based on rotary echo refocusing, to produce images of solids contrasted by T2rho. 相似文献