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21.
Zhang TG Zhao Y Song K Asselberghs I Persoons A Clays K Therien MJ 《Inorganic chemistry》2006,45(24):9703-9712
A series of conjugated (porphinato)zinc(II)-based chromophores structurally related to [5-(4-dimethylaminophenylethynyl)-15-(5-nitrothienyl-2-ethynyl)-10,20-bis(3,5-bis(3,3-dimethyl-1-butyloxy)phenyl)]zinc(II) were synthesized using metal-catalyzed cross-coupling reactions involving [5-bromo-15-triisopropylsilylethynyl-10,20-diarylporphinato]zinc(II), [5-bromo-15-(4-dimethylaminophenylethynyl)-10,20-diarylporphinato]zinc(II), [5-(4-dimethylaminophenylethynyl)-15-ethynyl-10,20-diarylporphinato]zinc(II), and [5-(4-nitrophenylethynyl)-15-ethynyl-10,20-diarylporphinato]zinc(II), along with appropriately functionalized aryl, thienyl (or thiophenyl), thiazolyl, benzothiazolyl, and carbazolyl precursors. The linear and nonlinear optical properties of these asymmetrically 5,15-substitued-(10,20-diarylporphinato)zinc(II) chromophores that bear either 2-(9H-carbazol-9-yl)-thiophen-5-yl-ethynyl, 4-dimethylaminophenylethynyl, or 2-(N,N-diphenylamino)thiophen-5-yl-ethynyl electron-releasing groups and an electron-withdrawing group selected from 2-formyl-thiophen-5-yl-ethynyl, 2-(2,2-dicyanovinyl)-thiophen-5-yl-ethynyl, 4-nitrophenylethynyl, 6-nitrobenzothiazol-2-yl-ethynyl, or 5-nitrothiazol-2-yl-ethynyl are reported. The dynamic hyperpolarizabilities of these compounds were determined from hyper-Rayleigh light scattering measurements carried out at a fundamental incident irradiation wavelength (lambda(inc)) of 1300 nm; these measured beta1300 values ranged from 690 --> 1400 x 10(-30) esu. These data (i) show that these neutral dipolar molecules express substantial beta1300 values, (ii) highlight that reductions in the magnitude of the aromatic stabilization energy of (porphinato)metal-pendant arylethynyl groups have a significant impact upon the magnitude of the molecular hyperpolarizability, and (iii) provide insights into advantageous design modifications for closely related structures having potential utility in long-wavelength electrooptic applications. 相似文献
22.
23.
Improved Spectral Coverage and Fluorescence Quenching in Donor–acceptor Systems Involving Indolo[3‐2‐b]carbazole and Boron‐dipyrromethene or Diketopyrrolopyrrole 下载免费PDF全文
Adis Khetubol Sven Van Snick Melissa L. Clark Eduard Fron Eduardo Coutiño‐González Arvid Cloet Koen Kennes Yuliar Firdaus Maarten Vlasselaer Volker Leen Wim Dehaen Mark Van der Auweraer 《Photochemistry and photobiology》2015,91(3):637-653
A novel π‐conjugated triad and a polymer incorporating indolo[3,2‐b]‐carbazole (ICZ) and 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) were synthesized via a Sonogashira coupling. Compared to the parent BODIPY the absorption and fluorescence spectrum were for both compounds broader and redshifted. The redshift of the fluorescence and the decrease of the fluorescence quantum yield and decay time upon increasing solvent polarity were attributed to the formation of a partial charge‐transfer state. Upon excitation in the ICZ absorption band the ICZ fluorescence was quenched in both compounds mainly due to energy transfer to the BODIPY moiety. In a similar ICZ–π–DPP polymer (where DPP is diketopyrrolopyrrole), a smaller redshift of the absorption and fluorescence spectra compared to the parent DPP was observed. A less efficient quenching of the ICZ fluorescence in the ICZ–π–DPP polymer could be related to the unfavorable orientation of the transition dipoles of ICZ and DPP. The rate constant for energy transfer was for all compounds an order of magnitude smaller than predicted by Förster theory. While in a solid film of the triad a further redshift of the absorption maximum of nearly 100 nm was observed, no such shift was observed for the ICZ–π–BODIPY polymer. 相似文献
24.
Koen Sandra Alberto dos Santos Pereira Gerd Vanhoenacker Frank David Pat Sandra 《Journal of chromatography. A》2010,1217(25):4087-4099
A lipidomics strategy, combining high resolution reversed-phase liquid chromatography (RPLC) with high resolution quadrupole time-of-flight mass spectrometry (QqTOF), is described. The method has carefully been assessed in both a qualitative and a quantitative fashion utilizing human blood plasma. The inherent low technical variability associated with the lipidomics method allows to measure 65% of the features with an intensity RSD value below 10%. Blood plasma lipid spike-in experiments demonstrate that relative concentration differences smaller than 25% can readily be revealed by means of a t-test. Utilizing an advanced identification strategy, it is shown that the detected features mainly originate from (lyso-)phospholipids, sphingolipids, mono-, di- and triacylglycerols and cholesterol esters. The high resolution offered by the up-front RPLC step further allows to discriminate various isomeric species associated with the different lipid classes. The added value of utilizing a Jetstream electrospray ionization (ESI) source over a regular ESI source in lipidomics is for the first time demonstrated. In addition, the application of ultra high performance LC (UHPLC) up to 1200 bar to extend the peak capacity or increase productivity is discussed. 相似文献
25.
Brooks NR Schaltin S Van Hecke K Van Meervelt L Fransaer J Binnemans K 《Dalton transactions (Cambridge, England : 2003)》2012,41(23):6902-6905
The first examples of structurally characterised mixed-ligand metal-containing ionic liquids (ILs) are presented, synthesised by the use of different N-alkylimidazoles. The cations consist of two-coordinate silver(i) centres ligated by two different N-alkylimidazole ligands. It is shown that the resulting ionic liquids have lower melting points than the single ligand ILs. 相似文献
26.
Van Rossom W Caers J Robeyns K Van Meervelt L Maes W Dehaen W 《The Journal of organic chemistry》2012,77(6):2791-2797
In pursuit of highly preorganized macrocyclic host molecules for the complexation of anions, a series of oxacalix[2]arene[2]pyrimidine-based bis(thio)ureido receptors were synthesized and fully characterized. The pincer-like 1,3-alternate conformation of the oxacalix[4]arene scaffold, essential for an efficient host-guest interaction, was visualized by single-crystal X-ray analysis and supported by variable-temperature NMR studies. The anion binding properties of the receptors were evaluated via (1)H NMR titration experiments, showing intermolecular interactions with H(2)PO(4)(-), AcO(-), BzO(-), and Cl(-) ions. The host molecule bearing 4-nitrophenyl substituents on the bisurea binding pocket showed association constants in the range of 200-400 M(-1) in the strongly competitive solvent mixture of DMSO/0.5% H(2)O. 相似文献
27.
Pozo OJ Van Eenoo P Deventer K Delbeke FT 《Analytical and bioanalytical chemistry》2007,389(4):1209-1224
A screening method for the urinary detection of 34 exogenous anabolic steroids has been developed. The method involves an
enzymatic hydrolysis, liquid-liquid extraction and detection by liquid chromatography-tandem mass spectrometry. The use of
some adducts such as [M+NH4]+, [M+CH3COO]− and [M+H+MeOH]+ was necessary in order to detect some analytes at the required level (lower than 10 ng/ml). Two transitions were selected
for each analyte. Different concentration factors have been studied in order to increase the sensitivity. A concentration
factor of 50 was selected for the screening method although the high ion suppression observed under these conditions can hamper
its application as a quantitative method. The method was validated and limits of detection were obtained by spiking ten different
blank urine samples at five different concentration levels. Up to 29 analytes were detected in all spiked urines at the required
level. Limits of detection between 1 and 10 ng/ml were obtained for most analytes which fulfil current requirements. The applicability
of the method was shown by analysing positive samples. 相似文献
28.
Treatment of α-chloro-δ-(trimethylsilyloxy)ketimines, obtained by regiospecific alkylation of α-chloroketimines with 3-bromo-1-(trimethylsilyloxy)propane, with bases and nucleophiles leads to a variety of oxygen-containing heterocycles, including tetrahydrofurans and tetrahydropyrans. 相似文献
29.
Peter Nockemann Dr. Ben Thijs Dr. Kyra Lunstroot Dr. Tatjana N. Parac‐Vogt Prof. Dr. Christiane Görller‐Walrand Prof. Dr. Koen Binnemans Prof. Dr. Kristof Van Hecke Dr. Luc Van Meervelt Prof. Dr. Sergey Nikitenko John Daniels Dr. Christoph Hennig Dr. Rik Van Deun Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(6):1449-1461
The dissolution process of metal complexes in ionic liquids was investigated by a multiple‐technique approach to reveal the solvate species of the metal in solution. The task‐specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf2N]) is able to dissolve stoichiometric amounts of the oxides of the rare‐earth elements. The crystal structures of the compounds [Eu2(bet)8(H2O)4][Tf2N]6, [Eu2(bet)8(H2O)2][Tf2N]6?2H2O, and [Y2(bet)6(H2O)4][Tf2N]6 were found to consist of dimers. These rare‐earth complexes are well soluble in the ionic liquids [Hbet][Tf2N] and [C4mim][Tf2N] (C4mim=1‐butyl‐3‐methylimidazolium). The speciation of the metal complexes after dissolution in these ionic liquids was investigated by luminescence spectroscopy, 1H, 13C, and 89Y NMR spectroscopy, and by the synchrotron techniques EXAFS (extended X‐ray absorption fine structure) and HEXS (high‐energy X‐ray scattering). The combination of these complementary analytical techniques reveals that the cationic dimers decompose into monomers after dissolution of the complexes in the ionic liquids. Deeper insight into the solution processes of metal compounds is desirable for applications of ionic liquids in the field of electrochemistry, catalysis, and materials chemistry. 相似文献
30.
Pieter Van der VekenIstván Kertèsz Kristel SentenAchiel Haemers Koen Augustyns 《Tetrahedron letters》2003,44(33):6231-6234
(E)- and (Z)-fluoro-olefin analogues of potent dipeptidyl peptidase IV inhibitors were synthesized. A Wadsworth-Horner-Emmons reaction, followed by amide formation and reduction of the amide were used for the construction of the α-fluoro-α,β-unsaturated amine functionality. 相似文献