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971.
Sohini Bhattacharyya Szymon Sobczak Aleksandra Półrolniczak Dr. Syamantak Roy Dr. Debabrata Samanta Prof. Andrzej Katrusiak Prof. Dr. Tapas Kumar Maji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(24):6092-6097
Targeted synthesis of piezoresponsive small molecules and in-depth understanding of their mechanism is of utmost importance for the development of smart devices. This work reports the synthesis, structure and piezosensitivity of a bola-amphiphile 1,4-bis(pentyloxy)-2,5-bis(2-pyridineethynyl)-benzene ( C5-PPB ). Depending on the rate of compression, two different phases in C5-PPB can be generated. The ambient-pressure α-phase is stable up to 0.8 GPa, beyond which it undergoes an isostructural transformation to β-phase, accompanied by a clearly visible elongation of the crystal. This α-to-β phase transition requires the sample to be compressed slowly. When quickly compressed, phase α persists to about 1.5 GPa, beyond which its amorphization starts, accompanied by the appearance of irregular grooves on the largest faces. Mechanical pressure also affects the optical property of C5-PPB , which shows reversible mechanochromism with a green to cyan transformation in the emission, associated with a 15 nm shift in the maxima. The conductivity of C5-PPB as a direct outcome of its crystal packing has also been studied. 相似文献
972.
Nayana Adhikari Ankita Kashyap Anshul Shakya Surajit Kumar Ghosh Dibya Ranjan Bhattacharyya Hans Raj Bhat Udaya Pratap Singh 《Journal of heterocyclic chemistry》2020,57(6):2389-2399
A series of novel PABA-substituted 1,3,5-triazine derivatives were developed via microwave assisted synthesis and subsequently tested for antimalarial activity against chloroquine sensitive 3D7 strain of Plasmodium falciparum using chloroquine as standard. Antimalarial screening result showed that synthesized compounds exhibited IC50 in the range of 4.46 to 79.72 μg mL−1. Among the tested compounds, 4c and 4f showed significant antimalarial activity with low binding energies (BE) -172.32 and 160.41 kcal mol−1 via interacting with Arg122 through the involvement of COOH of the phenyl linked to 1,3,5-triazine. In conclusion, these core scaffolds can be used for future antimalarial drug development. 相似文献
973.
Sinha Anubhab Bharti Saurabh Kumar Samantaray A. K. Chakraborty G. Bhattacharyya R. 《Nonlinear dynamics》2018,93(3):1719-1739
Nonlinear Dynamics - In this paper, the dynamics of a non-ideally driven single-degree-of-freedom vibrating system will be explored in detail. The objective is to describe Sommerfeld effect in a... 相似文献
974.
Adsorption of a few heavy metals on natural and modified kaolinite and montmorillonite: a review 总被引:16,自引:0,他引:16
The feasibility of using two important and common clay minerals, kaolinite and montmorillonite, as adsorbents for removal of toxic heavy metals has been reviewed. A good number of works have been reported where the modifications of these natural clays were done to carry the adsorption of metals from aqueous solutions. The modification was predominantly done by pillaring with various polyoxy cations of Zr4+, Al3+, Si4+, Ti4+, Fe3+, Cr3+or Ga3+, etc. Preparation of pillared clays with quaternary ammonium cations, namely, tetramethylammonium-, tetramethylphosphonium- and trimethyl-phenylammonium-, N'-didodecyl-N, N'-tetramethylethanediammonium, etc, are also common. Moreover, the acid treatment of clays often boosted their adsorption capacities. The adsorption of toxic metals, viz., As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Zn, etc., have been studied predominantly. Montmorillonite and its modified forms have much higher metal adsorption capacity compared to that of kaolinite as well as modified-kaolinite. 相似文献
975.
Sanjukta Aich Tamal Sengupta Amit Bhattacharyya Samita Basu 《Journal of polymer science. Part A, Polymer chemistry》1999,37(21):3910-3915
The present work emphasises the investigation of photoinduced electron transfer reaction between an electron-donor fluorophore, N-vinyl carbazole (VCZ), grafted on a polymeric cellulose acetate film and an electron-acceptor, 1,4-dicyanobenzene, in the presence of an external magnetic field that serves as a powerful tool to identify the spin states where the initial electron transfer occurs and to modulate the course of the reaction as desire. Here initial electron transfer occurs in the singlet spin state, and the formation of exciplex increases in the presence of magnetic field. The maximum field effect is obtained in the solvent with medium dielectric constant (εmax) around 8.0. The εmax value indicates that the extent of charge transfer in this exciplex is less compared to other similar systems studied so far, owing to the characteristic binding of VCZ to the polymeric backbone through oxygen atom. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3910–3915, 1999 相似文献
976.
We explore the viability of a time-independent quantum adiabatic switching algorithm in the Fourier grid Hamiltonian (FGH) framework in the presence of degeneracy, avoided crossing, and chaos. The algorithm is simple and cost effective and provides information about the full eigenspectrum of the evolving Hamiltonian. It is shown to be capable of capturing accurately the change in the pattern of level spacing distribution statistics as one switches from a nonchaotic region of parameter values into the chaotic region. The Transition turns out to be less sharp than anticipated. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 133–141, 1998 相似文献
977.
The effect of horizontal as well as vertical temperature gradients on the stability of natural convection in a thin horizontal
layer of viscous, incompressible fluid is studied on the basis of linear theory. The boundaries are taken to be rigid, perfectly
thermally conducting, having prescribed temperatures and the horizontal temperature gradient is assumed to be small. It is
found that for Prandtl number greater than 0.13, the critical Rayleigh number is always larger than that for the corresponding
Benard problem. The preferred mode of disturbance is stationary and will be a transverse roll (having axes normal to the basic
flow) or a longitudinal roll (having axes aligned in the direction of the basic flow) depending on whether the Prandtl number
is less or larger than 1.7. Finally, it is shown that the instability is of thermal origin. 相似文献
978.
Yong‐Jin Pu Minoru Soma Eishun Tsuchida Hiroyuki Nishide 《Journal of polymer science. Part A, Polymer chemistry》2000,38(22):4119-4127
Conjugated polymers alternatively involving m‐phenylenevinylene or p‐phenylenevinylene and a triphenylamine moiety in the main chain were synthesized via a Wittig–Horner‐type polycondensation of 4‐diformyl‐4′,4″‐dimethyl‐triphenylamine or 4‐diformyl‐4′,4″‐dimethoxy‐triphenylamine with m‐xylene‐bis(diethylphosphonate) or p‐xylene‐bis(diethylphosphonate). A high glass‐transition temperature (ca. 120 °C) and thermal stability (5% weight loss at temperatures greater than 450 °C) were observed for all polymers. These polymers, especially poly(methyltriphenylamine‐alt‐p‐phenylenevinylene), fluoresced a strong green color under UV irradiation, with a quantum efficiency of 50% for their chloroform solutions. Cyclic voltammetry showed a relatively low ionization potential (5.18–5.44 eV) for the polymers. These results suggest that these polymers satisfied the requisites of polymer materials for a single‐layer light‐emitting diode. The aminium radical derived from the oxidation of poly(triphenylamine‐alt‐m‐phenylenevinylene) satisfied both non‐Kekulé‐type π conjugation and ferromagnetic connectivity of the unpaired electrons and displayed a multiplet ground state. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4119–4127, 2000 相似文献
979.
980.
P. Chaudhuri S.K. Adhikari B. Talukdar S. Bhattacharyya 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):217-220
A three-parameter correlated wave function for the helium ground state is used to study the scattering reaction , where Ps stands for positronium atom. An exact analytical expression is constructed for the first Born scattering amplitude
for Ps formation from helium. Based on this numerical results are presented for both differential and total cross-sections.
It is demonstrated that the inner electronic correlation of the target atom plays a crucial role in explaining the discrepency
between theory and experiment.
Received: 9 April 1998 / Revised: 29 September 1998
/ Accepted: 19 October 1998 相似文献