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991.
Jose María Moreno Aneta Wojnicz Juan Luis Steegman Maria F. Cano‐Abad Ana Ruiz‐Nuño 《Biomedical chromatography : BMC》2013,27(4):502-508
We have developed a method of liquid chromatography in tandem with mass spectrometry to monitor therapeutic levels of imatinib in plasma, a selective inhibitor of protein tyrosine kinase. After solid‐phase extraction of plasma samples, imatinib and its internal standard, imatinib‐D8, were eluted with Zorbax SB‐C18 at 60 °C, under isocratic conditions through a mobile phase consisting of 4 mm ammonium formate, pH: 3.2 (solution A) and acetonitrile solution B. The flow rate was 0.8 mL/min with 55% solution A + 45% solution B. Imatinib was detected and quantified by mass spectrometry with electrospray ionization operating in selected‐reaction monitoring mode. The calibration curve was linear in the range 10–5000 ng/mL, the lower limit of quantitation being 10 ng/mL. The method was validated according to the recommendations of the Food and Drug Administration, including tests of matrix effect (bias < 10%) and recovery efficiency (>80 and <120%). The method is precise (coefficient of variance intra‐day <2% and inter‐day <7%), accurate (95–108%), sensitive and specific. It is a simple method with very fast recording time (1.2 min) that is applicable to clinical practice. This will permit improvement of the pharmacological treatment of patients. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
992.
Irene Ojeda María Moreno‐Guzmán Araceli González‐Cortés Paloma Yáñez‐Sedeño José M. Pingarrón 《Electroanalysis》2013,25(9):2166-2174
Electrochemical immunosensors for ceruloplasmin (Cp) are reported for the first time. Two configurations involving magnetic beads (MBs) functionalized with Protein A or Streptavidin for immobilization of Cp antibodies were compared, using competitive immunoassay with synthesized alkaline phosphatase‐Cp conjugate. Upon capturing MBs‐immunoconjugates onto screen‐printed carbon electrodes, quantification of Cp was accomplished by DPV measurement of 1‐naphthol generated after 1‐naphthylphosphate addition. Linear ranges of calibration curves and detection limits were 0.1–1000 µg/mL and 0.040 µg/mL (Protein A‐MBs), and 0.025–20 µg/mL and 0.018 µg/mL (Strept‐MBs). Good results were obtained in the determination of Cp in spiked human serum samples. 相似文献
993.
R. Valiente F. Rodríguez J. A. Aramburu M. Moreno M. T. Barriuso C. Sousa C. de Graaf 《International journal of quantum chemistry》2002,86(2):239-244
The variations experienced by the energy Eu(π) of the eu(π)→b1g (~x2–y2) charge‐transfer transition of (C2H5NH3)2CdCl4:Cu2+ upon pressure in the 0‐ to 40‐kbar range have been measured at room temperature by means of a sapphire anvil cell. These data reveal that Eu(π) undergoes a red shift of 1400 cm?1 on passing from ambient pressure to 40 kbars. To understand this puzzling result theoretical calculations of ?Eu(π)/?Req and ?Eu(π)/?Rax have been performed where Req and Rax mean the equatorial and axial Cu2+–Cl? distances of the elongated CuCl64? complex, respectively. All results indicate that ?Eu(π)/?Req and ?Eu(π)/?Rax for Req=228 pm and Rax=297 pm are indeed negative. Moreover ab initio complete active space self‐consistent field (CASSCF/CASPT2) and density functional calculations lead to ?Eu(π)/?Rax values, which are about 10 times smaller than those of ?Eu(π)/?Req. From the ensemble of experimental and theoretical results, it is concluded that a pressure of 40 kbars gives rise to a decrement of ≈25 pm of the axial distance and at the same time to an increase of ≈7 pm of the equatorial one. It is stressed that the present study on a diluted Jahn–Teller impurity lies far beyond the current possibilities of X‐ray absorption structure techniques. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 相似文献
994.
R. Castro M. V. G. Moreno R. Natera F. García-Rowe M. J. Hernández C. G. Barroso 《Chromatographia》2002,56(1-2):57-61
Summary Ion-exclusion chromatography (IEC) and capillary electrophoresis (CE) have been compared for determination of organic acids
in samples of Sherry wine vinegar. The accuracy of each technique was evaluated by use of the standard addition method. There
were no differences between the techniques at a significance level of 5%, except for determination of malic acid by CE. Both
analytical methods were used to analyse sixteen samples of Sherry wine vinegar supplied by different producers. The regression
coefficients (r
2) for analysis by IEC and CE exceeded 0.94 for all acids. Results from both methods were in good agreement and the methods
are sufficiently selective and sensitive to be applied directly to sherry wine vinegars. 相似文献
995.
Merz K Moreno M Löffler E Khodeir L Rittermeier A Fink K Kotsis K Muhler M Driess M 《Chemical communications (Cambridge, England)》2008,(1):73-75
The remarkably distinct reactivity of hydridozinc heterobimetallic cubanes [(HZnOtBu)4-n(thf LiOtBu)n] 1a-1d towards CO2 is reported--the hydride transfer from Zn-H to CO2 is drastically accelerated in the presence of Li ions in 1b-1d which led to the respective metal formate hydrates; the systems are inspiring models for the selective conversion of water gas into formates on lithium-promoted ZnO supports. 相似文献
996.
Pérez Pavón JL Herrero Martín S García Pinto C Moreno Cordero B 《Analytica chimica acta》2008,629(1-2):6-23
This article reviews the most recent literature addressing the analytical methods applied for trihalomethanes (THMs) determination in water samples. This analysis is usually performed with gas chromatography (GC) combined with a preconcentration step. The detectors most widely used in this type of analyses are mass spectrometers (MS) and electron capture detectors (ECD). Here, we review the analytical characteristics, the time required for analysis, and the simplicity of the optimised methods. The main difference between these methods lies in the sample pretreatment step; therefore, special emphasis is placed on this aspect. The techniques covered are direct aqueous injection (DAI), liquid-liquid extraction (LLE), headspace (HS), and membrane-based techniques. We also review the main chromatographic columns employed and consider novel aspects of chromatographic analysis, such as the use of fast gas chromatography (FGC). Concerning the detection step, besides the common techniques, the use of uncommon detectors such as fluorescence detector, pulsed discharge photoionization detector (PDPID), dry electrolytic conductivity detector (DELCD), atomic emission detector (AED) and inductively coupled plasma-mass spectrometry (ICP-MS) for this type of analysis is described. 相似文献
997.
The reaction of 2-pyridone with benzyl bromide in the absence of base and under solvent-free conditions has been studied experimentally and by computational methods. This reaction was one of the first reported examples in which modification of selectivity under microwave irradiation was observed. C- and/or N-alkylations were obtained depending on the benzyl halide and the heating system. N-Alkylation through mechanism A (SN2 mechanism) is kinetically favoured while C-alkylation through an SN1-type mechanism is thermodynamically favoured and is observed under microwave irradiation. Two SN1-type mechanisms (mechanisms B and C) have been calculated, mechanism C being a kind of SNi. The influence of the pyridone/benzyl bromide ratio was studied. A second molecule of pyridone stabilizes the transition state and assists the leaving of the bromide ion. The occurrence of C-alkylation under microwave irradiation is explained by the predominance of the thermodynamic control in these conditions. Under microwave irradiation N-alkylation through an SN1-type mechanism (mechanism C) can also occur. The dependence of the outcome of N-alkylation on the benzyl bromide ratio has been explained by a shift in the mechanism from SN2 to SN1 under microwave irradiation. Computational calculations have shown to be a useful tool for determination of the origin of the selectivity under microwave irradiation. 相似文献
998.
A 3-21+G energy surface corresponding to the proton transfer reaction in the hydroperoxyl anion solvated by one water molecule presents interesting topological features. In particular the intrinsic reaction coordinate that begins at the transition state does not lead to a minimum but to a saddle point of second order passing through two branching points. A new strategy to obtain the true reaction path in these cases is proposed. 相似文献
999.
Cioffi C Campidelli S Sooambar C Marcaccio M Marcolongo G Meneghetti M Paolucci D Paolucci F Ehli C Rahman GM Sgobba V Guldi DM Prato M 《Journal of the American Chemical Society》2007,129(13):3938-3945
Single-wall carbon nanohorns (SWNHs) are a new class of material that is closely related to single-wall carbon nanotubes. Here, we describe the synthesis and characterization of a series of SWNHs functionalized with ethylene glycol chains and porphyrins. Functionalization of carbon nanohorns has been achieved using two different synthetic protocols: (1) direct attack of a free amino group on the nanohorn sidewalls (nucleophilic addition) and (2) amidation reaction of the carboxylic functions in oxidized nanohorns. The nanohorn derivatives have been characterized by a combination of several techniques, and the electronic properties of the porphyrin/nanohorn assemblies (SWNH/H2P) have been investigated by electrochemistry, spectroelectrochemistry, and a series of steady-state and time-resolved spectroscopy. The cyclic voltammetry curve of nanohorn/porphyrin conjugate 6 showed a continuum of faradic and pseudocapacitive behavior, which is associated with multiple-electron transfers to and from the SWNHs. Superimposed on such a pseudocapacitive current, the curve also displays three discrete reduction peaks at -2.26, -2.57, and -2.84 V and an oxidation peak at 1.12 V (all attributed to the porphyrin moiety). Steady-state and time-resolved fluorescence demonstrated a quenching of the fluorescence of the porphyrin in SWNH/H2P conjugates 5 and 6 compared to the reference free base porphyrin. Transient absorption spectra permitted the electron-transfer process between the porphyrins and the carbon nanostructures to be highlighted. 相似文献
1000.