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排序方式: 共有414条查询结果,搜索用时 15 毫秒
1.
NMR screening techniques in drug discovery and drug design 总被引:7,自引:0,他引:7
Brian J. Stockman Claudio Dalvit 《Progress in Nuclear Magnetic Resonance Spectroscopy》2002,41(3-4):187-231
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The diagonal elements of the first and second order spinless density matrices have been calculated for the lowest excited1
P and3
P terms of Be, B+ and C++ using wavefunctions at different levels of approximations published in the literature. The analysis of these functions has
resulted in a new interpretation of Hund's first rule in terms of an anisotropic screening effect. 相似文献
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E. Marklová 《Chromatographia》1997,45(1):195-198
Summary Thin-layer chromatography (TLC) is a rapid, reliable and inexpensive screening technique for diagnosis of inherited metabolic
diseases (IMD). Our screening program encompasses five main situations where the use of TLC is considered to be vindicated:
(i) analysis of amino acids; (ii) screening for sugar defects; (iii) detection of pathological oligosaccharidurias; (iv) screening
for organic acid disorders; and (v) detection of abnormalities in tryptophan metabolism. Examples are presented of chromatograms
obtained from pathological samples.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
6.
Several derivatization procedures with o-phthaldialdehyde-N-acetylcysteine (OPA-NAC) were compared for a rapid analysis of primary aliphatic short-chain monoamines in water samples by HPLC using a LiChorospher analytical separation column (100RP18 mm i.d., 5 μm). Both the solution and the solid-support assisted off-line derivatization on C18 SPE cartridges were inadequate options because of beginning degradation processes of the instable isoindol derivatives during their transfer to the analytical column. This problem was precluded with the on-column or solid-support assisted on-line derivatization. In the last mentioned procedure, the derivatization took place in a Hypersil C18 precolumn ( mm i.d., 30 μm) connected with an additional preconcentration step resulting in better detection limits (0.002-0.040 μg ml−1 requiring only 150 μl of water sample) than in the on-column procedure (0.08-0.16 μg ml−1). The improved sample handling, the better control of parameters affecting reaction rates, the fully automation of this method with only 10 min analysis time for each sample are further advantageous. The potential of the solid-support assisted on-line derivatization was outlined and applied to water samples from several sources. Recovery values near 100% were obtained. 相似文献
7.
An on-line supercritical fluid extraction (SFE) system coupled to a continuous flow manifold including a UV detector was used as a screening system to extract astaxanthin from crayfish, which was found to be the major carotenoid present in the samples. This compound constitutes the principal additive used to dye salmon flesh. The flow manifold was used to confirm the presence of astaxanthin in the crustacean samples. Also, an HPLC/UV-vis method was used to ascertain that this compound was the major carotenoid extracted under the optimum SFE conditions employed. The influence of SFE operating variables such as pressure, temperature, equilibration time, extraction time, trap temperature, and volume of CO2 modifier was examined in order to maximize the efficiency of analyte extraction. The use of supercritical CO2 enables the expeditious, selective, quantitative extraction of astaxanthin from crustaceans. 相似文献
8.
Spectrafluorimetric method for the rapid screening of toxic heavy metals in water samples 总被引:1,自引:0,他引:1
B. San Vicente de la RivaJ.M. Costa-Fernández R. PereiroA. Sanz-Medel 《Analytica chimica acta》2002,451(2):203-210
A fast and inexpensive sensitive screening test for recognising potential wastewater contamination by the presence of highly toxic heavy metals is described. The test is based on the reaction of the toxic heavy metals Hg(II), Cd(II), Pb(II) and Ag(I) with 6-mercaptopurine (6-MP) to produce highly fluorescent complexes.Optimum experimental conditions include a buffer of pH 7.2 (0.1 M citric acid/0.2 M Na2HPO4), a chelating reagent concentration of 6×10−4 M and the addition of 10−4 M of o-phenanthroline. The fluorescence emitted by the complexes was measured at 380 and 540 nm for excitation and emission wavelengths, respectively.Detection limits of 4, 3, 6 and 3 μg l−1 were achieved for Hg, Cd, Pb and Ag. Relative standard deviation (R.S.D.) were between ±2 and ±6% of the fluorescence signals for five identical samples. Potential interference effects from other heavy metals (Zn, Mn, Co, Fe, Ni and Cu), which could affect the response of the proposed screening test was investigated. Results showed that none of these metals give rise to noticeable fluorescence signals under the above described experimental conditions.Finally, the capability of the proposed heavy metal screening test for the analysis of contaminated water samples is discussed. 相似文献
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Estimation of diuretic drugs in biological fluids by HPLC 总被引:1,自引:0,他引:1
Summary This critical review of different methods proposed for the determination and screening of diuretics is directed mainly, because of its potential application, towards highperformance liquid chromatography. 相似文献