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131.
Multiresidue analysis of multiclass plant growth regulators in grapes by liquid chromatography/tandem mass spectrometry 总被引:1,自引:0,他引:1
Oulkar DP Banerjee K Ghaste MS Ramteke SD Naik DG Patil SB Jadhav MR Adsule PG 《Journal of AOAC International》2011,94(3):968-977
A selective and rapid multiresidue analysis method is presented for simultaneous estimation of 12 plant growth regulators (PGRs), namely, auxins (indol-3-acetic acid, indol-3-butyric acid, and naphthyl acetic acid), cytokinins (kinetin, zeatin, and 6-benzyladenine), gibberellic acid (GA3), abscisic acid, and synthetic compounds, namely, forchlorfenuron, paclobutrazole, isoprothiolane, and 2,4-dichlorophenoxy acetic acid (2,4-D) in bud sprouts and grape berries at the development stages of 2-3 and 6-8 mm diameters, which are the critical phases when exogenous application of PGRs may be necessary to achieve desired grape quality and yield. The sample preparation method involved extraction of plant material with acidified methanol (50%) by homogenization for 2 min at 15000 rpm. The pH of the extract was enhanced up to 6 by adding ammonium acetate, followed by homogenization and centrifugation. The supernatant extract was cleaned by SPE on an Oasis HLB cartridge (200 mg, 6 cc). The final extract was measured directly by LC/MS/MS with electrospray ionization in positive mode, except for 2,4-D, GA3, and abscisic acid extracts, which required analysis in negative mode. Quantification by multiple reaction monitoring (MRM) was supported with full-scan mass spectrometric confirmation using "information-dependent acquisition" triggered with MRM to "enhanced product ionization" mode of the hybrid quadrupole-ion trap mass analyzer. The LOQ of the test analytes varied between 1 and 10 ng/g with associated recoveries of 80-120% and precision RSD <25% (n = 8). Significant matrix-induced signal suppression was recorded when the responses for pre- and postextraction spikes of analytes were compared; this could be resolved by using matrix-matched calibration standards. The method could successfully be applied in analyzing incurred residue samples and would, therefore, be useful in precisely deciding the necessity and dose of exogenous applications of PGRs on the basis of measured endogenous levels. 相似文献
132.
Pavagada Jagannathamurthy Ramesh Kanakapura Basavaiah Mysore Ranganath Divya Nagaraju Rajendraprasad Kanakapura Basavaiah Vinay Hosakere Doddarevanna Revanasiddappa 《Journal of Analytical Chemistry》2011,66(5):482-489
Doxycycline hyclate (DOX), a broad spectrum antibiotic with activity against a wide range of gram-positive and gram-negative bacteria, is widely used
as a pharmacological agent and as an effector molecule in inducible gene expression system. Three simple, selective, rapid,
accurate, precise and cost-effective spectrophotometric methods for the determination of DOX in bulk drug and in tablets have
been developed and validated. First method (method A) is based on the measurement of absorbance of DOX in 0.1 M HCl at 240
nm. The second method (method B) is based on the measurement of yellow chromogen at 375 nm which is formed in 0.1 M NaOH.
The third method is based on the measurement of 2: 1 complex formed between DOX and iron(III) in H2SO4 medium, the complex peaking at 420 nm (method C). The optimum conditions for all the three methods are optimized. Beer’s
law was obeyed over the ranges 2.5–50.0, 1.50–30.0 and 10–100 g/mL for method A, method B and method C, respectively. The
apparent molar absorptivity values are calculated to be 1.03 × 104, 1.73 × 104, and 5.21 × 103 L mol−1 cm−1 for method A, method B, and method C, respectively. The Sandell sensitivity, limit of detection (LOD) and limit quantification (LOQ) values are also reported. All the methods were validated in accordance with current ICH guidelines. The developed methods
were employed with high degree of precision and accuracy for the estimation of total drug content in commercial tablet formulations
of DOX. 相似文献
133.
An efficient Zn(II)-catalyzed intermolecular double hydroamination of 1,3-enynes with aryl hydrazines, for the synthesis of pyrazolines, has been discussed. 相似文献
134.
Sergey V. Ushakov Divya Nag Alexandra Navrotsky 《Journal of Thermal Analysis and Calorimetry》2011,104(1):351-356
The severe heating of soil during wildfires and prescribed burns may result in adverse effects on soil fertility due to organic
matter loss. No rapid and reliable procedure exists to evaluate soil organic matter (SOM) losses due to heating. Enthalpy
of SOM combustion correlates with organic matter content. Quartz is a ubiquitous mineral in soils and has a remarkably constant
composition and reversible α–β phase transition at 575 °C. We suggest that SOM content in heated and unheated soils can be
compared using the ratio of SOM combustion enthalpy on heating to the β–α quartz transition enthalpy measured on cooling of
the same sample. This eliminates the need to dry and weigh the samples, making possible field applications of the proposed
method. The feasibility of using the (ΔH
comb SOM)/(ΔH
β–α Qz) ratio was established with experiments on soil samples heated in the laboratory and the method was then used for evaluation
of SOM loss on two pile burn sites at UC Berkeley’s Blodgett Forest Research Station in Georgetown, California. 相似文献
135.
136.
Satyawati S. Joshi Prajakta R. Patil Madhav S. Nimase P.P. Bakare 《Journal of nanoparticle research》2006,8(5):635-643
The electrochemical synthesis of alpha Fe2O3 nanoparticles was performed using quaternary ammonium salts viz. TPAB, TBAB and TOAB in an organic medium by optimizing current density and molar concentration of the ligand. The role of ligands in the formation of α phase, structure and magnetic properties was investigated in details. The effect of increasing chain length on the particle size confirmed that as the chain length increases from propyl to octyl, the particle size decreases. X-ray diffraction spectra of as prepared samples and TEM analysis confirmed the amorphous nature of iron oxide. TEM showed beads of iron oxide joined together with a size distribution in the range of 6–30 nm. The Mossbauer studies also support this observation that for the lowest particle size, the line width is broader which successively reduces with increase in particle size. Iron oxide capped with TOAB indicated superparamagnetic nature at room temperature. The resultant internal magnetic field of 506 mm/s due to hyperfine splitting clearly established the formation of α-Fe2O3 The infrared spectroscopy and pH measurements revealed the binding of tetra alkyl ligand with iron oxide. The IR spectra and the increase in basicity of as prepared samples confirmed the formation of hydrated iron oxide. Above 800°C the spectra indicated only iron oxide. Surface area obtained by BET method was 205 m2/g. 相似文献
137.
Dilip P. Patil 《manuscripta mathematica》1993,80(1):239-248
LetO be a monomial curve in the affine algebraice-space over a fieldK andP be the relation ideal ofO. ifO is defined by a sequence ofe positive integers somee-1 of which form an arithmetic sequence then we construct a minimal set of generators forP and write an explicit formula for μ(P). 相似文献
138.
JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic method with densitometric UV detection at λ = 232 nm has been developed for standardization of... 相似文献
139.
140.
Sujata Patil R. Nagarajan L. C. Gupta C. Godart R. Vijayaraghavan B. D. Padalia 《Hyperfine Interactions》1988,42(1-4):1063-1066
The series Eu2M3Si5 (M=Ni, Cu, Pd, Rh) have been synthesised for the first time. The Ni, Cu, Pd systems form in U2Co3Si5 type structure.151Eu Mössbauer spectroscopy shows that Eu is in valence fluctuating (VF) state in Ni system, while in Cu and Pd systems it is in stable divalent state. These observations are further confirmed by magnetic susceptibility studies. The material Eu2Rh3Si5 shows two lines in the Mössbauer resonance, one of which shows VF behaviour. 相似文献