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251.
Nissilä T Sainiemi L Karikko MM Kemell M Ritala M Franssila S Kostiainen R Ketola RA 《Lab on a chip》2011,11(8):1470-1476
We developed a nanoreactor chip based system to mimic phase I metabolic reactions of small organic compounds. The microchip, made of silicon, has an anatase-phase titanium dioxide (TiO(2)) nanolayer coating for photocatalysis and an integrated electrospray ionization (ESI) tip for direct mass spectrometric (MS) analysis. This novel method for mimicking phase I metabolic reactions uses an on-chip TiO(2)-nanolayer and an external UV-lamp to induce photocatalyzed chemical reactions of drug compounds in aqueous solutions. The reactions of selected test compounds (verapamil, metoprolol, propranolol, lidocaine, 2-acetamidofluorene, and S-methylthiopurine) produced mostly the same main products as phase I metabolic reactions induced by human liver microsomes, rat hepatocytes, or cytochrome P enzymes, showing hydroxylation, dehydrogenation, and dealkylations as the main photocatalytic reactions. With this method it is possible to detect reactive and toxic products (mimicking reactive metabolites) due to the absence of biological matrices and an immediate analysis. The method used is sensitive: only 20-40 pmol (1-10 ng) of a substrate was needed for the experiment, thus it provides an inexpensive method for screening possible metabolites of new drug candidates. Due to small dimensions of the microchip, diffusion lengths are suitable for the high reaction rates, thus providing a rapid analysis as the reaction products can be detected and identified directly after the photoinduced reactions have occurred. The method shows a similar performance to that of electrochemistry, a commonly used technique for mimicking phase I metabolism. 相似文献
252.
Barry ST Gordon PG Ward MJ Heikkila MJ Monillas WH Yap GP Ritala M Leskelä M 《Dalton transactions (Cambridge, England : 2003)》2011,40(37):9425-9430
A new homoleptic sublimable indium(III) guanidinate, (In[(N(i)Pr)(2)CNMe(2)](3) (1), was synthesized from a facile high-yield procedure. Compound 1 crystallized is a P1 space group; a = 10.5989(14) ?, b = 11.0030(15) ?, c = 16.273(2) ?, α = 91.190(2)°, β = 96.561(2)°, γ = 115.555(2)°; R = 3.50%. Thermogravimetric analysis showed 1 to produce elemental indium as a residual mass. Thermolysis in a sealed NMR tube showed carbodiimide and protonated dimethyl amine by (1)H NMR. Chemical vapour deposition experiments above 275 °C with air as the reactant gas showed 1 to readily deposit cubic indium oxide with good transparency. 相似文献
253.
Thymidine 5′-bis[3-acetyloxy-2-cyano-2-(2-phenylethylcarbamoyl)propyl]phosphate (1) has been prepared and the removal of phosphate protecting groups by hog liver carboxyesterase (HLE) at pH 7.5 and 37 °C has been followed by HPLC. The first detectable intermediates are the (R(P))- and (S(P))-diastereomers of the monodeacetylated triester 14, which subsequently undergo concurrent retro-aldol condensation to diester 4 and enzyme-catalyzed hydrolysis to the fully deacetylated triester 15. The former pathway predominates, representing 90% of the overall breakdown of 14. The diester 4 undergoes the enzymatic deacetylation 700 times less readily than the triester, but gives finally thymidine 5′-monophosphate as the desired main product. To elucidate the potential toxicity of the electrophilic 2-cyano-N-(2-phenylethyl)acrylamideby-product 17 released upon the deprotection, the hydrolysis of 1 has also been studied in the presence of glutathione (GSH). 相似文献
254.
Armentano A Cerný J Riese M Taherkhani M Ben Yezzar M Müller-Dethlefs K 《Physical chemistry chemical physics : PCCP》2011,13(13):6077-6084
A laser spectroscopic investigation of phenol...Ar(n) (n = 1-6) clusters in the first electronically excited state (S(1)) and the cationic ground state (D(0)) is reported. Resonance enhanced two-photon ionisation (R2PI) spectra have been recorded for the investigation of the S(1) state. The origins of S(1)← S(0) (S(1)0(0)) transition of phenol...Ar(n) (n = 1, 2,4-6) are all red shifted compared to the S(1)0(0) state of the monomer by 33 cm(-1), 67 cm(-1), 10 cm(-1), 20 cm(-1), 44 cm(-1), respectively. However, the origin of the phenolAr(3) cluster is blue shifted by 25 cm(-1). For the investigation of the ionic ground state photoionization efficiency (PIE) and mass-analyzed-threshold ionization (MATI) spectroscopy have been applied. The spectra of phenol...Ar(3) and phenol...Ar(4) yield values for the ionization energy (IE) of 68,077 ± 15 cm(-1) and 67,948 ± 15 cm(-1). With the combination of theoretical methods and R2PI, PIE and MATI spectroscopy, the major species present have been positively identified. 相似文献
255.
Indrek Jõgi Kaupo Kukli Mikko Ritala Jaan Aarik Jun Lu 《Microelectronic Engineering》2010,87(2):144-228
We have investigated electrical properties of laminated atomic layer deposited films: ZrO2-Ta2O5, ZrO2-Nb2O5-Ta2O5, ZrO2-TaxNb1−xO5 and Ta2O5-ZrxNbyOz. Even though the capacitances of laminates were often higher compared to films of constituent materials with similar thickness, considerably higher charge storage factors, Q, were achieved only when tetragonal ZrO2 was stabilized in ZrO2-Ta2O5 laminate and when the laminate thickness exceeded 50 nm. The decreased Q values in the case of most laminates were the result of increased leakage currents. In the case of thinner films only Ta2O5-ZrxNbyOz stack possessed capacitance density and Q value higher than reference HfO2. Concerning the conduction mechanisms, in the case of thinner films, the Ta2O5 or TaxNb1−xO5 apparently controlled the leakage either by Richardson-Schottky emission or Poole-Frenkel effect. 相似文献
256.
Tong X Armentano A Riese M Benyezzar M Pimblott SM Müller-Dethlefs K Ishiuchi S Sakai M Takeda A Fujii M Dopfer O 《The Journal of chemical physics》2010,133(15):154308
The dissociation energetics in the phenol(+)?Ar(2)(2π) cluster ion have been investigated using photoionization efficiency and mass analyzed threshold ionization spectroscopy. The appearance energies for the loss of one and two Ar atoms are determined as ~210 and ~1115?cm(-1), respectively. The difference between the appearance energy for the first Ar ligand in phenol(+)?Ar(2)(2π) and the dissociation energy of the phenol(+)?Ar(π) dimer (535cm(-1)) is explained by the isomerization of one π-bound Ar ligand to the OH binding site (H-bond) upon ionization. The energy difference between phenol(+)?Ar(2)(2π) and phenol(+)?Ar(2)(H/π) could also be estimated to be around 325cm(-1), which corresponds roughly to the difference of the binding energy of a π-bound and H-bound Ar ligands. The binding energy of the H-bound Ar atom in phenol(+)?Ar(2)(H/π) is derived to be ~905cm(-1). 相似文献
257.
Mikko H. Junttila 《Tetrahedron letters》2010,51(26):3430-3432
New catalysts/cosolvents as hydrolysis aids and the properties of the catalyst/cosolvent that effect the efficiency of the hydrolysis aid for the hydrolysis of osmate(VI) esters of aliphatic olefins are presented. Also, the effect of pH of the reaction media on the specific and general acid-catalysed hydrolysis of osmate(VI) esters of conjugated aromatic olefins is presented. 相似文献
258.
J. Santeri Puranen Mikko J. Vainio Mark S. Johnson 《Journal of computational chemistry》2010,31(8):1722-1732
The atom‐centered partial charges‐approximation is commonly used in current molecular modeling tools as a computationally inexpensive alternative to quantum mechanics for modeling electrostatics. Even today, the use of partial charges remains useful despite significant advances in improving the efficiency of ab initio methods. Here, we report on new parameters for the EEM and SFKEEM electronegativity equalization‐based methods for rapidly determining partial charges that will accurately model the electrostatic potential of flexible molecules. The developed parameters cover most pharmaceutically relevant chemistries, and charges obtained using these parameters reproduce the B3LYP/cc‐pVTZ reference electrostatic potential of a set of FDA‐approved drug molecules at best to an average accuracy of 13 ± 4 kJ mol?1; thus, equipped with these parameters electronegativity equalization‐based methods rival the current best non‐quantum mechanical methods, such as AM1‐BCC, in accuracy, yet incur a lower computational cost. Software implementations of EEM and SFKEEM, including the developed parameters, are included in the conformer‐generation tool BALLOON , available free of charge at http://web.abo.fi/fak/mnf/bkf/research/johnson/software.php . © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
259.
David S. Casadio Dr. Santeri Aikonen Dr. Anna Lenarda Dr. Martin Nieger Dr. Tao Hu Dr. Stefan Taubert Prof. Dage Sundholm Dr. Mikko Muuronen Dr. Tom Wirtanen Dr. Juho Helaja 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(16):5283-5291
Mildly thermal air or HNO3 oxidized activated carbons catalyse oxidative dehydrogenative couplings of benzo[b]fused heteroaryl 2,2’-dimers, e.g., 2-(benzofuran-2-yl)-1H-indole, to chiral 3,3’-coupled cyclooctatetraenes or carbazole-type migrative products under O2 atmosphere. DFT calculations show that the radical cation and the Scholl-type arenium cation mechanisms lead to different products with 2-(benzofuran-2-yl)-1H-indole, being in accord with experimental product distributions. 相似文献
260.