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11.
New metal based triazoles (1–12) have been synthesized by the interaction of novel Schiff base ligands (L1–L3) with the Co(II), Ni(II), Cu(II) and Zn(II) metal ions. The Schiff base ligands and their all metal(II) complexes have been thoroughly characterized using various physical, analytical and spectroscopic techniques. In vitro bacterial and fungal inhibition studies were carried out to examine the antibacterial and antifungal profile of the Schiff bases in comparison to their metal(II) complexes against two Gram‐positive, four Gram‐negative and six fungal strains. The bioactivity data showed the metal(II) complexes to have more potent antibacterial and antifungal activity than their uncomplexed parent Schiff bases against one or more bacterial and fungal species. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
12.
Dr. Saud Asif Ahmed Qiao-Bo Liao Qi Shen Dr. Mirza Muhammad Faran Ashraf Baig Juan Zhou Cai-Feng Shi Dr. Pir Muhammad Dr. Sumaira Hanif Prof. Kai Xi Prof. Xing-Hua Xia Prof. Kang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(57):12996-13001
Layered/two-dimensional covalent organic frameworks (2D COF) are crystalline porous materials composed of light elements linked by strong covalent bonds. Interlayer force is one of the main factors directing the formation of a stacked layer structure, which plays a vital role in the stability, crystallinity, and porosity of layered COFs. The as-developed new way to modulate the interlayer force of imine-linked 2D TAPB-PDA-COF (TAPB = 1,3,5-tris(4-aminophenyl)benzene, PDA = terephthaldehyde) by only adjusting the pH of the solution. At alkaline and neutral pH, the pore size of the COF decreases from 34 Å due to the turbostratic effect. Under highly acidic conditions (pH 1), TAPB-PDA-COF shows a faster and stronger turbostratic effect, thus causing the 2D structure to exfoliate. This yields bulk quantities of an exfoliated few/single-layer 2D COF, which was well dispersed and displayed a clear Tyndall effect (TE). Furthermore, nanopipette-based electrochemical testing also confirms the slipping of layers with increase towards acidic pH. A model of pH-dependent layer slipping of TAPB-PDA-COF was proposed. This controllable pH-dependent change in the layer structure may open a new door for potential applications in controlled gas adsorption/desorption and drug loading/releasing. 相似文献
13.
Hanif?HadipourEmail author Seyed?Akbar?Jafari 《The European Physical Journal B - Condensed Matter and Complex Systems》2015,88(10):270
Local density approximation (LDA) and Green function effective Coulomb (GW) calculations are performed to investigate the effect of electronic correlations on the electronic properties of both graphene and graphane. The size of band gap in graphane increases from 3.7 eV in LDA to 4.9 eV in GW approximation. By calculating maximally localized Wannier wave functions, we evaluate the necessary integrals to get the Hubbard U and the exchange J interaction from first principles for both graphene and graphane. Our ab-initio estimates indicate that in the case of graphene, in addition to the hopping amplitude t ~ 2.8 eV giving rise to the Dirac nature of low lying excitations, the Hubbard U value of ~8.7 eV gives rise to a super-exchange strength of J AFM ~ 3.5 eV. This value dominates over the direct (ferromagnetic) exchange value of J FM ~ 1.6 eV. This brings substantial Mott-Heisenberg aspects into the problem of graphene. Moreover, similarly large values of the Hubbard and super-exchange strength in graphane suggests that the nature of gap in graphane has substantial Mott character. 相似文献
14.
Chunxiang Hu Yunyun He Shuiliang Chen Yongmei Zhu Muddasir Hanif Haoqing Hou 《Journal of Solid State Electrochemistry》2014,18(10):2797-2802
A binder-free activated carbon paper (ACP) was simply prepared for electric double-layer capacitors by the carbonization of filter paper, followed by heat-air activation at a lower temperature. The electrochemical cells assembled using the as-prepared ACP-470 provides a high specific capacitance of 296.4 F g?1 at current density of 0.5 A g?1 and a high rate performance at a current density of 150 A g?1 with a capacitance of 191.2 F g?1 and a high cycle ability at 10,000 recycles with 100 % capacitance retention. In addition, the ACP has a lower electrical resistivity and provides an effective energy storage performance with a maximum energy density of 41.2 Wh kg?1 and a maximum power density of 138.0 kW kg?1 in a voltage range of 1 V. 相似文献
15.
Nonlinear Dynamics - In this article, we present a system of coupled short pulse equations as integrability condition of associated generalized linear eigenvalue problem. We obtain system of... 相似文献
16.
McKeown NB Hanif S Msayib K Tattershall CE Budd PM 《Chemical communications (Cambridge, England)》2002,(23):2782-2783
Network polymers exhibiting large surfaces areas (900-1000 m2g-1) are prepared by the highly efficient dibenzodioxane forming reaction between meso-tetrakis(pentafluorophenyl)porphyrin and a rigid bis(catechol) monomer. 相似文献
17.
Anderson MW Holmes SM Hanif N Cundy CS 《Angewandte Chemie (International ed. in English)》2000,39(15):2707-2710
18.
F. He L. L. Tian X. Y. Tian H. Xu Y. H. Wang W. J. Xie M. Hanif J. L. Xia F. Z. Shen B. Yang F. Li Y. G. Ma Y. Q. Yang J. C. Shen 《Advanced functional materials》2007,17(9):1551-1557
1,4‐di(4′‐N,N‐diphenylaminostyryl)benzene (DPA‐DSB) is a well known compound with a large two‐photon absorption (TPA) section and strong fluorescence in solution. However, the ease with which it crystallizes results in the formation of discontinuous crystalline phases during vacuum deposition processes, thereby greatly limiting its applicability in solid‐state devices. A cruciform dimer of DPA‐DSB, 2,5,2′,5′‐tetra(4′‐N,N‐diphenylaminostyryl)biphenyl (DPA‐TSB) is reported, wherein two DPA‐DSB molecules are linked through a central biphenyl bond. The DPA‐TSB molecules take on a cruciform configuration because of the steric crowding around the central biphenyl core, which has the effect of efficiently suppressing crystalline and intermolecular interactions. The neat DPA‐TSB solid shows strong green–blue fluorescence because of both steady‐state absorption as well as TPA. The DPA‐TSB solid exhibits a photoluminescence (PL) efficiency (ηsolid) of 29 % and a solid‐state two‐photon action cross section (δηsolid) of 954 GM (1 GM = 1 × 10–50 cm4 s photon–1 molecule–1), which is much greater than for the model compound DPA‐DSB (ηsolid = 16 % and δηsolid = 150 GM, where δ is the TPA cross section and η is the fluorescence quantum yield). Based on its high PL efficiency, good film‐forming ability, and strong TPA, DPA‐TSB seems to be a good candidate for applications in solid‐state optical devices. 相似文献
19.
Effective Relaxations and Partitioning Schemes for Solving Water Distribution Network Design Problems to Global Optimality 总被引:2,自引:0,他引:2
Hanif D. Sherali Shivaram Subramanian G.V. Loganathan 《Journal of Global Optimization》2001,19(1):1-26
In this paper, we address the development of a global optimization procedure for the problem of designing a water distribution network, including the case of expanding an already existing system, that satisfies specified flow demands at stated pressure head requirements. The proposed approach significantly improves upon a previous method of Sherali et al. (1998) by way of adopting tighter polyhedral relaxations, and more effective partitioning strategies in concert with a maximal spanning tree-based branching variable selection procedure. Computational experience on three standard test problems from the literature is provided to evaluate the proposed procedure. For all these problems, proven global optimal solutions within a tolerance of 10–4% and/or within 1$ of optimality are obtained. In particular, the two larger instances of the Hanoi and the New York test networks are solved to global optimality for the very first time in the literature. A new real network design test problem based on the Town of Blacksburg Water Distribution System is also offered to be included in the available library of test cases, and related computational results are presented. 相似文献
20.
Disjunctive Programs can often be transcribed as reverse convex constrained problems with nondifferentiable constraints and
unbounded feasible regions. We consider this general class of nonconvex programs, called Reverse Convex Programs (RCP), and
show that under quite general conditions, the closure of the convex hull of the feasible region is polyhedral. This development
is then pursued from a more constructive standpoint, in that, for certain special reverse convex sets, we specify a finite
linear disjunction whose closed convex hull coincides with that of the special reverse convex set. When interpreted in the
context of convexity/intersection cuts, this provides the capability of generating any (negative edge extension) facet cut.
Although this characterization is more clarifying than computationally oriented, our development shows that if certain bounds
are available, then convexity/intersection cuts can be strengthened relatively inexpensively. 相似文献