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461.
Wipf P George KM 《Synlett : accounts and rapid communications in synthetic organic chemistry》2010,2010(4):644-648
The regioselective palladium-catalyzed cross-coupling reactions of 2,4,7-trichloroquinazoline with various aryl- and heteroarylboronic acids are reported. An efficient, sequential strategy was developed that provides access to novel, functionalized heterocycles. 相似文献
462.
We give a representation of the (infinite-dimensional) complex Clifford algebra on the Hilbert space of square-integrable
complexvalued functions on the Cantor set. 相似文献
463.
Sofia Kara Slimane Frédérick Roussel Ulrich Maschke 《Journal of Polymer Science.Polymer Physics》2007,45(1):18-27
A comparative study of the phase diagrams and morphology of blends of poly(2‐ethylhexylacrylate) and low molecular weight liquid crystals (LCs) prepared under different conditions is presented. Two LCs are used; one is the 4‐cyano‐4′‐n‐pentyl‐biphenyl and the other is the eutectic mixture of cyanoparaphenylenes known as E7. Two series of blends are prepared under different conditions. The first series is obtained by the polymerization induced phase separation (PIPS) process under UV‐curing starting from a monomeric mixture, while the second series is prepared by a combination of the solvent induced phase separation and the thermally induced phase separation process starting from a mixture containing a commercial polymer with known molecular weight. Using gel permeation chromatography, it is found that the polymer molecular weight of the UV‐cured systems decreases with the concentration of LC in the precursor mixture. The experimentally obtained phase diagrams of these two series of systems show a miscibility shift at the composition where the molar mass of the polymer in the PIPS/UV blend exceeds that of the commercial polymer. Data are rationalized in terms of the Flory‐Huggins theory of isotropic mixing and the Maier‐Saupe theory of nematic order. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 18–27, 2007 相似文献
464.
?i?dem Hopa Raif Kurtaran Mahir Alkan Hulya Kara Robert Hughes 《Transition Metal Chemistry》2010,35(8):1013-1018
Co(II), Ni(II) and Cu(II) nitrate complexes with btmpp, namely ([Co(btmpp)(H2O)2(NO3)]NO3 (1), [Ni(btmpp)(H2O)(NO3)]NO3 (2) and [Cu(btmpp)(MeOH)(NO3)]NO3 (3), where btmpp = 2,6-bis(3,4,5-trimethyl-N-pyrazolyl)pyridine), have been synthesized and characterized by physicochemical and spectroscopic methods. The crystal structure
of complex 1 has been determined by single crystal diffraction at 100K. In all the complexes, btmpp is coordinated in a tridentate mode
through its nitrogen atoms. One of the nitrates in complex 1 is terminally bonded to the metal center through the oxygen atom, whereas the other one is out of the coordination sphere.
The Co(II) atom in complex 1 is hexa-coordinated with a CoN3O3 distorted octahedral environment. Decomposition of three complexes was analyzed thermogravimetrically. All three complexes
decompose similar to explosive material. 相似文献
465.
Duane E. Weisshaar Gary W. Earl Eric M. Villa Jessica L. Zierke Christopher J. Fry Kara L. Becvar Shik Ki Li Matthew C. Schafer 《国际化学动力学杂志》2010,42(4):221-225
Quaternary ammonium compounds are produced worldwide in hundreds of millions of pound volume annually for a plethora of end‐uses from fabric‐care formulations to asphalt emulsifiers, typically from nongreen alkylating reagents. The kinetics of a reaction employing dimethyl carbonate (DMC) as a green alkylating agent was investigated using three trialkylamines (tributylamine, trihexylamine, and trioctylamine) at several temperatures. Arrhenius and Eyring analysis of the data showed that values of Ea (79 kJ/mol), ΔH? (75 kJ/mol), and ΔS? (220 J/(mol K)) were the same for all three amine reactants, consistent with a report that Ea is independent of alkyl chain length when the chain length is greater than three carbons. Although rates are significantly slower with DMC than with other alkylating reagents, the resulting methyl carbonate anion has advantages for clean anion metathesis, which is important for some applications, especially those involving ionic liquids. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 221–225, 2010 相似文献
466.
Sinem Odabaşıoğlu Raif Kurtaran Akin Azizoglu Hülya Kara Sevi Öz Orhan Atakol 《Central European Journal of Chemistry》2009,7(3):402-409
A new cadmium (II) complex, [Cd(bdmpp)(SeCN)2(H2O)] (1) (where bdmpp = 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine), has been synthesized and characterized by elemental and spectral (IR, 1H-NMR and 13C-NMR, UV-Vis) analyses, differential scanning calorimetry, and single crystal X-ray diffraction studies. X-ray analysis showed that the structure was crystallized in the monoclinic space group Cc with a = 9.031(2), b = 13.884(3), c = 16.910(3) Å, and Z = 4. The geometry around the cadmium atom is distorted octahedral with a CdN3Se2O setup. The N atoms of the SeCN are engaged in two strong intermolecular H-bonding interactions forming a 3D supramolecular polymeric network. The geometry and vibrational frequencies of complex 1 computed with the DFT methods (BLYP, B3LYP, B3PW91, MPW1PW91) are in better agreement with experiment than those obtained with the ab-initio method except for the bond angles. The molecular orbital diagram has been also calculated and visualized at the B3LYP/LanL2DZ level of theory. 相似文献
467.
Bilgen Osman Ali Kara Emel Demirbel Senay K?k Necati Be?irli 《Applied biochemistry and biotechnology》2012,168(2):279-294
Designing an immobilised metal ion affinity process on large-scale demands that a thorough understanding be developed regarding the adsorption behaviour of proteins on metal-loaded gels and the characteristic adsorption parameters to be evaluated. In view of this requirement, interaction of ??-amylase as a model protein with newly synthesised magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter, 53?C212???m) was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerising of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterised by N2 adsorption/desorption isotherms, electron spin resonance, elemental analysis, scanning electron microscope and swelling studies. Cu2+ ions were chelated on the m-poly(DVB?CVIM) beads and used in adsorption of ??-amylase in a batch system. The maximum ??-amylase adsorption capacity of the m-poly(DVB?CVIM)?CCu2+ beads was determined as 10.84?mg/g at pH?6.0, 25?°C. The adsorption data were analyzed using three isotherm models, which are the Langmuir, Freundlich and Dubinin?CRadushkevich isotherm models. The pseudo-first-order, pseudo-second-order, modified Ritchie??s-second-order and intraparticle diffusion models were used to test dynamic experimental data. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. 相似文献
468.
It is shown that cytochrome c heme lyase (CCHL) attaches heme covalently to peptides composed of the N-terminal segment of cyt c fused to a non-heme containing protein, lending insight into the substrate specificity of CCHL and providing a new route to artificial heme proteins. 相似文献
469.
A new method using multiwalled carbon nanotubes as an SPE adsorbent was developed for the sensitive determination of trace iron and lead prior to flame atomic absorption spectrometry analysis. Iron and lead as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline chelates were adsorbed quantitatively on multiwalled carbon nanotubes at a pH of 6.0 and easily eluted with 10 mL 1 M HNO3. The influences of matrix ions were also examined. The LOD values for iron and lead were calculated as 1.3 and 2.9 microg/L, respectively. Validation of the presented procedure was performed by the analysis of TMDA 54.4 fortified lake water and HR-1 Humber River sediment certified reference materials. The method was successfully applied to the determination of trace iron and lead in real environmental samples, and excellent results were achieved. 相似文献
470.
Using the relativistic Hartree-Fock (HFR) method developed by Cowan, we calculated the energy levels, Landé g-factors, and lifetimes for nd (n = 5–25), ns (n = 6–24), ng (n = 5–25), nf (n = 4–22), and np (n = 6–25) excited levels of doubly ionized lanthanum (La III, Z = 57). We compared the results with previously reported calculations
and experiments. 相似文献