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791.
Thu-Hoai Bui Maithaa Karkmaz Eric Puzenat Chantal Guillard Jean-Marie Herrmann 《Research on Chemical Intermediates》2007,33(3-5):421-431
Organic pollutant removal is the main field of water photocatalytic decontamination. Molecules such as pesticides (herbicides, insecticides, fungicides, etc.) or dyes are totally destroyed and mineralized into CO2 and innocuous inorganic anions (Cl?, SO 4 2? , NO 3 ? ). Presently, two azo-dyes (i.e., containing the-N=N-azo group), Cibacron Brilliant Red 3B-A and Remazol Black B (Reactive Black 5), were successfully destroyed and totally mineralized. The stoichiometric coefficients of the total degradation, as well as the mass balances have been established with different analytical tools: TOC for carbon, DCO for oxygen, ionic-HPLC for heteroatoms (N, S, P) and pH-metry for hydrogen. Moreover, nitrogen balance has been established during the photocatalytic degradation of the dyes by considering not only nitrate and ammonium ions in the solution, but also the formation of N2 in the gas phase. The quantification of N2 molecules suggests that the photocatalytic degradation of azo-compounds is 100% selective in generating gaseous dinitrogen. The reaction mechanism was first determined in a laboratory photoreactor, before degradation in larger pilot solar photoreactors, using UV-A radiant flux from the sun in a new sub-discipline called heliophotocatalysis. 相似文献
792.
Color and fluorescence changes were expressed at the interface between two different polyhydrazone polymer films, induced by hydrazone bond exchange and component recombination through the interface, resulting in an extension of conjugation. 相似文献
793.
Rataboul F Copéret C Lefort L de Mallmann A Thivolle-Cazat J Basset JM 《Dalton transactions (Cambridge, England : 2003)》2007,(9):923-927
A new tantalum-hydride supported on zirconium hydroxide [(triple bond SiO)(2)Zr(H)-O-Ta(H)(x)-(OSi triple bond)] (x = 1 or 3) was prepared using surface organometallic chemistry and its catalytic properties in the propane metathesis reaction were assessed showing improved activity and selectivities in comparison to the tantalum-hydride supported on silica. 相似文献
794.
Fraïsse F Nedelec JM Grolier JP Baba M 《Physical chemistry chemical physics : PCCP》2007,9(17):2137-2141
Isothermal crystallization of a high molecular weight PEO (Mw=4,000,000) has been investigated using photoDSC. Combining light irradiation, heating and DSC analysis, photoDSC demonstrates good capability to follow the in situ photo- and thermo-ageing of semi-crystalline polymers. Isothermal crystallization of PEO was performed at 55 degrees C. After ageing at different temperatures ranging from 0 to 90 degrees C and for various periods of time, the kinetics of this crystallization was found following the Avrami theory. Avrami exponent, n, was found between 0.9 and 1.4 evidencing a one-dimension growth process. It was also found that the isothermal crystallization rate (i.e. reciprocal crystallization half-time) was exposure time, ageing temperature and light intensity dependent which makes this kinetic parameter a good indicator of following and comparing the degradation of the semi-crystalline polymers. 相似文献
795.
Boudinet D Benwadih M Altazin S Verilhac JM De Vito E Serbutoviez C Horowitz G Facchetti A 《Journal of the American Chemical Society》2011,133(26):9968-9971
Organic thin-film transistor (OTFT) performance depends on the chemical characteristics of the interface between functional semiconductor/dielectric/conductor materials. Here we report for the first time that OTFT response in top-gate architectures strongly depends on the substrate chemical functionalization. Depending on the nature of the substrate surface, dramatic variations and opposite trends of the TFT threshold voltage (~±50 V) and OFF current (10(5)×!) are observed for both p- and n-channel semiconductors. However, the field-effect mobility varies only marginally (~2×). Our results demonstrate that the substrate is not a mere passive mechanical support. 相似文献
796.
Xuereb F Chaignepain S Breilh D Godde F Saux MC Lenz C Glueckmann M Schmitter JM 《Analytical and bioanalytical chemistry》2011,400(7):2073-2084
The extended use of protein drugs in therapeutics has created the need for their quantification in human plasma. A methodology
using the therapeutic protein itself as internal standard for quantitative analysis by multiple reaction monitoring (MRM)
has been designed and applied to epoetin beta, a recombinant human erythropoietin (rhEPO). After depletion of major proteins,
plasma samples were desalted and enriched in rhEPO by reversed phase liquid chromatography prior to tryptic cleavage. Differential
isotopic labeling of peptides was performed by derivatization with 2-methoxy-4,5-dehydro-imidazole. A light version (four
hydrogen atoms) of this reagent was used for plasma peptides. Tryptic peptides obtained from pure rhEPO were derivatized with
a heavy version (four deuterium atoms) of the same reagent and used as internal standards. Two rhEPO tryptic peptides with
three MRM transitions per peptide were selected for quantification. This strategy provided a quantification limit close to
50 amol of epoetin beta per microliter of plasma (equivalent to 1.7 ng/mL), i.e., well below the expected therapeutic concentrations
in plasma (around 100–500 amol/μL). 相似文献
797.
Rozanska X Sautet P Delbecq F Lefebvre F Borshch S Chermette H Basset JM Grinenval E 《Physical chemistry chemical physics : PCCP》2011,13(35):15955-15959
The process of grafting H(3)PMo(12)O(40) onto silica surfaces is studied using periodic density functional theory methods. For surfaces with a high hydroxyl coverage, the hydroxyl groups are consumed by the polyoxometalate protons, resulting in water formation and the creation of a covalent bond between the polyoxometalate and the surface, and mostly no remaining acidic proton on the polyoxometalate. When the surfaces are partially dehydroxylated and more hydrophobic, after temperature pretreatment, less covalent and hydrogen bonds are formed and the polyoxometalate tends to retain surface hydroxyl groups, while at least one acidic proton remains. Hence the hydroxylation of the surface has a great impact on the chemical properties of the grafted polyoxometalate. In return, the polyoxometalate species affects the compared stability of the partially hydroxylated silica surfaces in comparison with the bare silica case. 相似文献
798.
Claire Le ManachAurélie Baron Régis GuillotBoris Vauzeilles Jean-Marie Beau 《Tetrahedron letters》2011,52(13):1462-1465
A library of paclitaxel (taxol) mimics was obtained by a straightforward strategy involving rational design and an efficient synthesis of a simplified taxane core substitute, together with a click-chemistry combinatorial search for phenylisoserine side-chain surrogates. 相似文献
799.
Nikonova OA Nedelec JM Kessler VG Seisenbaeva GA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(18):11622-11628
The use of an inorganic perrhenate ligand in the structure of early-transition-metal alkoxide precursors permits to achieve uniform self-assembly of the primary nanoparticles produced by their hydrolysis. The latter has been carried out in a hydrocarbon reaction medium by the addition of water with vigorous stirring, either in the pure form or in solutions in parent alcohols. The self-assembly is guided by the surface charge enhanced by the presence of strongly coordinated anions as determined by zeta potential measurements. The aggregation process has been followed in real time by nanoparticle tracking analysis (NanoSight technique). The reaction products are spherical aggregates with a size that can be efficiently controlled through the polarity of the reaction medium. The produced nanobeads have been characterized by TEM, SEM-EDS, DLS, nitrogen adsorption, and FTIR. The coordination of metal centers has been investigated using EXAFS spectroscopy. The aggregates remain amorphous on thermal treatment of up to 700 °C (24 h treatment) but crystallize when treated at 1000 °C. This latter process is associated with the total loss of rhenium content and offers early-transition-metal oxides as products. 相似文献
800.
Raquez JM Vanderstappen S Meyer F Verge P Alexandre M Thomassin JM Jérôme C Dubois P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(36):10135-10143
Cross‐linked poly(ε‐caprolactone) (PCL)‐based polyesterurethane (PUR) systems have been synthesized through Diels–Alder reactions by reactive extrusion. The Diels–Alder and retro‐Diels–Alder reactions proved to be useful for enhancing the molecular motion of PCL‐based systems, and therefore their crystallization ability, in the design of cross‐linked semicrystalline polymers with one‐way and two‐way shape‐memory properties. Successive reactions between α,ω‐diol PCL (PCL2), furfuryl alcohol, and methylene diphenyl 4,4′‐diisocyanate straightforwardly afforded the α,ω‐furfuryl PCL‐based PUR systems, and subsequent Diels–Alder reactions with N,N‐phenylenedimaleimide afforded the thermoreversible cycloadducts. The cross‐linking density could be modulated by partially replacing PCL‐diol with PCL‐tetraol. Interestingly, the resulting PUR systems proved to be semicrystalline cross‐linked polymers, the melting temperature of which (close to 45 °C) represented the switching temperature for their shape‐memory properties. Qualitative and quantitative measurements demonstrated that these PUR systems exhibited one‐way and two‐way shape‐memory properties depending on their cross‐linking density. 相似文献