全文获取类型
收费全文 | 202篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 158篇 |
晶体学 | 2篇 |
数学 | 5篇 |
物理学 | 41篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有206条查询结果,搜索用时 15 毫秒
81.
A flow enthalpimetric method for the determination of glucose is presented. The method is based on the reaction of glucose with 1,4-benzoquinone in the presence of immobilized glucose oxidase. d-Glucose concentrations ranging from 0.02 to 75mM can be determined. The method is applicable to the determination of glucose in soft drinks, wines, beers, jams and serum. 相似文献
82.
A flow-injection system with an immobilized enzyme reactor is proposed for the determination of l-phenylalanine. Phenylalanine dehydrogenase from Rhodoccus sp. M4 was immobilized on tresylated poly (vinyl alcohol) beads (13 mum) and packed into a stainless-steel column (5 cm x 4 mm i.d.). Serum sample was deproteinized with tungstic acid and filtered through an ultrafiltration membrane. The sample solution (30 mul) was injected into the carrier stream (water). The NADH formed was detected at 465 nm (excitation at 340 nm). The calibration graph was linear for 0.9-600 mum l-phenylalanine; the detection limit was 0.3 mum. The sample throughout was 25 h(-1) without carryover. The half-life period of the immobilized enzyme was 23 days. 相似文献
83.
A method for flow enthalpimetric determination of H2O2 is described. The method uses manganese dioxide to catalyse the decomposition of H2O2. The catalyst is stable enough to be used for at least 500 analyses. H2O2 in the concentration range 0.01–10mM is determined with coefficients of variation < 2%. The method has been used for determination of glucose in a non-alcoholic beverage and wines, with glucose oxidase as the peroxide-producing enzyme. 相似文献
84.
A fluorimetri method is described for the determination of glycerol, 1,2-propanediol and triglycerides in serum by high-performance liquid chromatography with an on-line post-column reactor containing immobilized glycerol dehydrogenase. Before separation, triglycerides are cleaved with lipase and esterase. The polyhydric alcohols are separated from each other on a Finepak SIL C18 (10 μm) column with water as eluent. The NADHI produced from the enzymatic reaction is monitored by fluorimetry. Calibration curves are linear between 0.01 mM and 1.0 mM for glycerol or 2.0 mM for 1,2-propanediol. The method gave satisfactory results for control sera. 相似文献
85.
Immobilized mannitol dehydrogenase is used for the determination of D-fructose in a flow-injection system. The enzyme is immobilized on poly(vinyl alcohol) beads. The oxidation of NADH occurs simultaneously and the disappearance of NADH is measured fluorimetrically. The response is linearly related to fructose concentration in the range 6–600 μM; 30 samples per hour can be analysed. The immobilized enzyme retains over 80% of its initial activity after repetitive use for 2 months. 相似文献
86.
T. Shinohara A. Furusawa S. Hayashibe S. Yamaguchi T. Kamiyama 《Hyperfine Interactions》1982,12(1):297-305
Time-integral - perturbed angular correlation measurements have been made on156Gd nuclei in TbZn1–xCux using two Ge(Li) detectors. The hyperfine fields at156Gd nuclei in TbZn1–xCux at 77 K are found to be –177±26, –104±24 and –27±38 kOe for TbZn, TbZn0.64Cu0.36 and TbZn0.54Cu0.46, respectively. These values indicate that the transferred hyperfine fields at Gd nuclei are positive due to the exchange interaction of s-f type. 相似文献
87.
Kishikawa K Furusawa S Yamaki T Kohmoto S Yamamoto M Yamaguchi K 《Journal of the American Chemical Society》2002,124(8):1597-1605
Compact and simple nondiscoid mesogens, trialkoxybenzoic anhydrides 2-11 ((RO)(3)C(6)H(2)-CO-O-CO-C(6)H(2)(OR)(3), R = C(2)H(5), n-C(3)H(7), n-C(4)H(9), n-C(6)H(13), n-C(8)H(17), n-C(10)H(21), n-C(12)H(25), n-C(14)H(29), n-C(16)H(33), and (S)- and (R)-3,7-dimethyloctyl) were designed and synthesized, and their superstructures were investigated by polarized light microscopy, differential scanning calorimetry, calculation (MM2 and AM1), circular dichroism spectroscopy, and X-ray diffraction. As the result, in the cases of 5-9 and 11, the half-disk molecules in the liquid crystal phases were self-assembled by the dipole-dipole interaction between their carbonyl groups to a column in which the molecules were piled up in an alternately antiparallel manner, and the columns were interdigitated each other. The observed interdigitations were highly directional in the perpendicular direction to the column axis. In the case of compound 11 which has (S)- or (R)-3,7-dimethyloctyl groups, a helical organization of the molecules in the column was estimated from the peaks in the circular dichroism spectra. This is the first report of a one-directionally interdigitated columnar phase, and these compounds are the first liquid crystalline acid anhydrides. It was demonstrated that a -CO-O-CO- moiety is useful as a polar junction in liquid crystalline compounds. 相似文献
88.
Normal-phase high-performance liquid chromatographic determination of spiramycin in eggs and chicken
Furusawa N 《Talanta》1999,49(2):461-465
A precise method is presented for determination of residual spiramycin (SP) in chicken eggs and tissues by high-performance liquid chromatography (HPLC). The sample preparation was performed by homogenizing with a mixture of acetonitrile and n-hexane (5:4, v/v) to minimize the fat amount followed by ultra-filtration using a MolCutII(R). The extracts containing SP were free from interfering compounds when examined by the normal-phase HPLC using a LiChrosorb(R) NH(2) column and a mobile phase of acetonitrile-water (85:15, v/v) with a photo-diode array detector. The average recoveries from spiked SP (0.1, 0.5 and 1.0 ppm) were in excess of 89.0% with coefficients of variation between 1.4 and 2.4%. The limit of detection was 0.1 ppm. 相似文献
89.
-potentials of a silica suspension and three types of polystyrene latex suspensions with different surface charge groups were measured, as a function of the particle concentration () in the suspension over a wide range, using the colloid vibration potential (CVP) technique. The concentration dependence of the-potential in silica suspension is explained well by Levine et al.s [1] cell model theory, verifying the applicability of the cell model to the CVP in silica suspension. However, the-potential of latex suspensions ordinarily decreases as the particle concentration increases, even after being corrected by the term of (1-). This tendency is especially noticeable in the systems that have particles with high surface charge densities. Furthermore, the conductivity measurements of these suspensions reveal that the conductivity of these systems, especially in their highly charged state, increases as the particle concentration is increased; opposite in tendency to silica suspensions. These new findings can be explained as follows: on the highly charged surface of a latex particle, a polyelectrolyte-like (hairy) layer is present, which overlaps at some point. This permits interparticle surface conduction and results in the abnormal behavior of CVP in these systems. 相似文献
90.
The effects of particle size on polyacrylamide (PAAm,M
w
=59×104, 500×104) adsorption were investigated using a series of well-characterized hematite (-Fe2O3) dispersions. The -Fe2O3 particles with highly monodisperse and nearly spherical shape ranged in radius from 23 nm to 300 nm. the maximum amount of PAAm adsorption (M
m
) in each system, showed a steady increase with decreasing particle radius and was influenced strongly by particle concentrations in the medium. Furthermore, it was realized that the diameter of -Fe2O3 particles after treatment with PAAm under different particle concentrations decreased with increasing particle concentration. The relation between particle concentration in the medium and particle size after treatment was also influenced by the medium pH, i.e., at the medium pH close to the isoelectric point of -Fe2O3 particles (pHo=9.2), the particle size after treatment increased with increasing particle concentration. All these results suggest that in the system of ultra-fine particles, the mixing process between particle-particle and polymerparticle will play an important role on the conformation of adsorbed polymer layer. 相似文献