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81.
By means of the X-ray diffraction method, quantum pharmacology analysis and quantitative structure-activity relationships
(QSAR) analysis, the structure-activity relationships of the herbicidal sulfonylureas and fused heterocyclic sulfonamides
were systematically studied. The results showed that the structure-activity relationships of these two kinds of herbicides
were identical and that the heterocyclic ring and sulfonyl moiety in the molecules were their pharmacophores which likely
bind in the same receptor sites of acetolactate synthase (ALS). According to these results, the initial model of these two
kinds of herbicides binding with the receptor was put forward.
Project supported by the National Natural Science Foundation of China (Grant No.29472056). 相似文献
82.
83.
Metabonomic study of biochemical changes in urinary of type 2 diabetes mellitus patients after the treatment of sulfonylurea antidiabetic drugs based on ultra‐performance liquid chromatography/mass spectrometry 下载免费PDF全文
A metabonomic study on biochemical changes in the urine of type 2 diabetes mellitus (T2DM) patients after the treatment of sulfonylurea (SU) antidiabetic drugs was performed. An ultra‐performance liquid chromatography/mass spectrometry (UPLC/MS) method was used to generate metabolic fingerprints for the metabonomic analysis of urinary samples obtained from 20 T2DM patients without any drug treatment and 20 T2DM patients treated with SU antidiabetic drugs and 20 normal glucose tolerance subjects. The resulting data were subjected to chemometric analysis (principal component analysis and partial least squares discriminant analysis) to investigate the effect of SU antidiabetic drugs on urinary metabolite profiles of T2DM patients. Biomarkers such as xanthine, phenylalanine, tryptophan, hippurate, phenylacetylglutamine, carnitine C8:1, carnitine C10:3, uric acid and citrate were found to be responsible for the separation of T2DM and SU‐treated groups, which indicates a potential effect of SU on energy metabolism, Tricarboxylic acid (TCA) cycle, gut microflora metabolism and oxidative stress. The study may be helpful to the understanding of the action of mechanism of SU antidiabetic drugs. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
84.
Based on a molecularly imprinted organic‐silica hybrid‐based stir bar, a pre‐treatment methodology was developed for enrichment of nicosulfuron in aqueous samples. The molecularly imprinted organic‐silica hybrid‐based coating on the outer surface of a glass stir bar was prepared by in‐situ polymerization using nicosulfuron as a template molecule, α‐methacrylic acid as a functional monomer, methacryloxypropytrimethoxysilane as a cross‐linker in the mixture of acetonitrile and trichloromethane (V/V, 7.5:1). To achieve the selective extraction of the target analyte from aqueous samples, several main parameters, including extraction time, pH value and contents of inorganic salt in the sample matrix were investigated. Evidence was also presented by the scanning electronic microscopic images of the imprinted and non‐imprinted stir bars. Then, the extraction efficiency of the stir bar was tested with separate experiments and competitive sorption experiments. These results showed that using six sulfonylureas as substrates the molecularly imprinted organic‐silica hybrid‐based stir bar gave high selectivity for the template, nicosulfuron compared to the non‐imprinted organic‐silica hybrid‐based stir bar. This sorption extraction was coupled to liquid chromatography ultraviolet detection allowing the determination of nicosulfuron from tap water. The method showed good recoveries and precision, 96.0% (RSD 2.7%, n=3) for tap water spiked with 0.125 nmol (25.00 mL sample), suggesting that the stir bar can be successfully applied to the pre‐concentration of nicosulfuron in real aqueous samples. 相似文献
85.
86.
Ru‐Song Zhao Chun‐Peng Diao Qing‐Feng Chen Xia Wang 《Journal of separation science》2009,32(7):1069-1074
In this paper, solid‐phase extraction (SPE) in combination with dispersive liquid–liquid microextraction (DLLME) has been developed as a sample pretreatment method with high enrichment factors for the sensitive determination of amide herbicides in water samples. In SPE–DLLME, amide herbicides were adsorbed quantitatively from a large volume of aqueous samples (100 mL) onto a multiwalled carbon nanotube adsorbent (100 mg). After elution of the target compounds from the adsorbent with acetone, the DLLME technique was performed on the resulting solution. Finally, the analytes in the extraction solvent were determined by gas chromatography–mass spectrometry. Some important extraction parameters, such as flow rate of sample, breakthrough volume, sample pH, type and volume of the elution solvent, as well as salt addition, were studied and optimized in detail. Under optimum conditions, high enrichment factors ranging from 6593 to 7873 were achieved in less than 10 min. There was linearity over the range of 0.01–10 μg/L with relative standard deviations of 2.6–8.7%. The limits of detection ranged from 0.002 to 0.006 μg/L. The proposed method was used for the analysis of water samples, and satisfactory results were achieved. 相似文献
87.
Encarnación Rodríguez‐Gonzalo Rita Carabias‐Martínez Edith Miranda Cruz Javier Domínguez‐Álvarez Jesús Hernández‐Méndez 《Journal of separation science》2009,32(4):575-584
In the present work we address the development of a simple and effective method for the determination of triazine herbicide residues in horticultural products by CE in nonaqueous media (NACE). Potato samples were selected as a representative matrix of such foods with a nonfatty content. Isolation of the analytes from the sample matrix was accomplished by extraction with organic solvents, assisted by ultrasound; a clean‐up step of the organic extracts was carried out with SPE, using an Oasis MCX® sorbent to retain the analytes directly from the organic medium. The detection limits achieved in spiked potatoes (1.7–4.0 μg/kg) were lower than the default value of maximum residue level (MRL) established by current EU legislation for pesticide residues in foodstuffs. The results obtained were compared with HPLC in order to evaluate the performance of the NACE procedure. 相似文献
88.
Summary Degradation products of chlorsulfuron, chlortoluron, diuron, fluometuron, isoproturon, linuron, metabenzthiazuron, metobromuron,
and monuron formed in the gas chromatographic injector have been used for identification of the respective herbicides. Mass
spectra of the derived compounds were obtained with a quadrupole mass spectrometric detector working in scan mode (20–450
amu). The compounds generated often depended on the solvent used for phenylurea herbicide injection (ethanol, methanol, dichloromethane,
and acetonitrile). When methanol and ethanol were used as solvents the major products formed from phenylureas were carbamic
acid esters. When acetonitrile or dichloromethane were used the main derivatives were phenylisocyanates. Chlorsulfuron and
metabenzthiazuron, however, generated a triazine plus a phenylsulfonamide and a benzothiazolamine, respectively, irrespective
of the solvent used. Linuron and diuron behaved similarly and gave degradation products with the same mass spectra. The thermal
reactions occurred instantaneously in the injector block and were promoted by the high temperature selected (300°C).
Detemination of the compounds derived from urea herbicides, by use of a 30 m BP10 column and a selected ion registering (SIR)
program based on two or three ions, can be used for sensitive detection of the presence of urea herbicides in environmental
extracts. With standards in methanol instrument detection limits ranged from 0.1 pg for chlorsulfuron (detected as 2-chlorobenzensulfonamide)
to 1 pg for monuron and metobromuron (both detected as their carbamic acid methyl esters).RSD were below 9% at the 5 ng L−1 level. The response was linearly dependent on quantily (r>0.9986) in the 5 ng L−1 to 25 μg L−1 range. Unequivocal identification of some phenylurea herbicides was not always possible because some herbicides with similar
structures, for example diuron and linuron, gave the same derivative. 相似文献
89.
Léa L. Freitas Eliane A. Suchara Vanira S. Benato Eduardo Carasek 《International journal of environmental analytical chemistry》2013,93(3):313-323
The aim of this study was to develop an analytical methodology for the determination of the herbicide pendimethalin in river waters in the towns of Turvo and Meleiro in the southern region of Santa Catarina State, Brazil. The method, based on solid phase microextraction (SPME) followed by separation and detection by gas chromatography (GC) and electron capture detection (ECD), respectively, was optimised and validated. The limits of detection (LOD) and quantification (LOQ) of 0.02 and 0.06?µg?L?1, respectively, and recovery values in the range of 86.2 (±11.5)% to 103.4 (±9.5)% were obtained. It was verified that 53 river water samples showed contamination by pendimethalin at levels that ranged from 0.06 to 0.38?µg?L?1. 相似文献
90.
Pereira Félix M. Gonçalves Adilson R. Ferraz André Silva Flávio T. Oliveira Samuel C. 《Applied biochemistry and biotechnology》2001,91(1-9):563-574
Applied Biochemistry and Biotechnology - Release of herbicides from lignin-based formulations follows a diffusion-controlled mechanism. For mathematical modeling of diffusive transport, the... 相似文献