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41.
I. V. Malkov V. V. Krivetskii D. I. Potemkin A. V. Zadesenets M. M. Batuk J. Hadermann A. V. Marikutsa M. N. Rumyantseva A. M. Gas’kov 《Russian Journal of Inorganic Chemistry》2018,63(8):1007-1011
Nanocrystalline tin dioxide modified by Pd and Pt clusters or by bimetallic PdPt nanoparticles was synthesized. Distribution of the modifers on the SnO2 surface was studied by high-resolution transmission electron microscopy and energy dispersive X-ray microanalysis with element distribution mapping. It was shown that the Pd/Pt ratio in bimetallic particles varies over a broad range and does not depend on the particle diameter. The effect of platinum metals on the reducibility of nanocrystalline SnO2 by hydrogen was determined. The sensing properties of the resulting materials towards 6.7 ppm CO in air were estimated in situ by electrical conductivity measurements. The sensor response of SnO2 modified with bimetallic PdPt particles was a superposition of the signals of samples with Pt and Pd clusters. 相似文献
42.
Qiuyue Ge Yangyang Liu Kejian Li Lifang Xie Xuejun Ruan Wei Wang Longqian Wang Tao Wang Wenbo You Liwu Zhang 《Angewandte Chemie (International ed. in English)》2023,62(27):e202304189
Solar-driven CO2 reduction reaction (CO2RR) is largely constrained by the sluggish mass transfer and fast combination of photogenerated charge carriers. Herein, we find that the photocatalytic CO2RR efficiency at the abundant gas-liquid interface provided by microdroplets is two orders of magnitude higher than that of the corresponding bulk phase reaction. Even in the absence of sacrificial agents, the production rates of HCOOH over WO3 ⋅ 0.33H2O mediated by microdroplets reaches 2536 μmol h−1 g−1 (vs. 13 μmol h−1 g−1 in bulk phase), which is significantly superior to the previously reported photocatalytic CO2RR in bulk phase reaction condition. Beyond the efficient delivery of CO2 to photocatalyst surfaces within microdroplets, we reveal that the strong electric field at the gas-liquid interface of microdroplets essentially promotes the separation of photogenerated electron-hole pairs. This study provides a deep understanding of ultrafast reaction kinetics promoted by the gas-liquid interface of microdroplets and a novel way of addressing the low efficiency of photocatalytic CO2 reduction to fuel. 相似文献
43.
We report the analysis of human rhinovirus serotype 2 (HRV2) on a commercially available lab-on-a-chip instrument. Due to lack of sufficient native fluorescence, the proteinaceous capsid of HRV2 was labeled with Cy5 for detection by the red laser (lambda ex 630 nm) implemented in the instrument. On the microdevice, electrophoresis of the labeled virus was possible in a BGE without stabilizing detergents, which is in contrast to conventional CE; moreover, analysis times were drastically shortened to the few 10 s range. Resolution of the sample constituents (virions, a contaminant present in all virus preparations, and excess dye) was improved upon adaptation of the separation conditions, mainly by adjusting the SDS concentration of the BGE. Purity of fractions from size-exclusion chromatography after labeling of virus was assessed, and affinity complex formation of the labeled virus with various recombinant very-low-density lipoprotein receptor derivatives differing in the number of concatenated V3 ligand binding repeats was monitored. Virus analysis on microchip devices is of particular interest for experiments with infectious material because of easy containment and disposal of samples. Thus, the employment of microchip devices in routine analysis of viruses appears to be exceptionally attractive. 相似文献
44.
Evenhuis CJ Hruska V Guijt RM Macka M Gas B Marriott PJ Haddad PR 《Electrophoresis》2007,28(20):3759-3766
Ionic electrophoretic mobilities determined by means of CE experiments are sometimes different when compared to generally accepted values based on limiting ionic conductance measurements. While the effect of ionic strength on electrophoretic mobility has been long understood, the increase in the mobility that results from Joule heating (the resistive heating that occurs when a current passes through an electrolyte) has been largely overlooked. In this work, a simple method for obtaining reliable and reproducible values of electrophoretic mobility is described. The electrophoretic mobility is measured over a range of driving powers and the extrapolation to zero power dissipation is employed to eliminate the effect of Joule heating. These extrapolated values of electrophoretic mobility can then be used to calculate limiting ionic mobilities by making a correction for ionic strength; this somewhat complicated calculation is conveniently performed by using the freeware program PeakMaster 5. These straightforward procedures improve the agreement between experimentally determined and literature values of limiting ionic mobility by at least one order of magnitude. Using Tris-chromate BGE with a value of conductivity 0.34 S/m and ionic strength 59 mM at a modest dissipated power per unit length of 2.0 W/m, values of mobility for inorganic anions were increased by an average of 12.6% relative to their values free from the effects of Joule heating. These increases were accompanied by a reduction in mobilities due to the ionic strength effect, which was 11% for univalent and 28% for divalent inorganic ions compared to their limiting ionic mobilities. Additionally, it was possible to determine the limiting ionic mobility for a number of aromatic anions by using PeakMaster 5 to perform an ionic strength correction. A major significance of this work is in being able to use CE to obtain reliable and accurate values of electrophoretic mobilities with all its benefits, including understanding and interpretation of physicochemical phenomena and the ability to model and simulate such phenomena accurately. 相似文献
45.
刘理蔚 《南昌大学学报(理科版)》1986,10(1):1
本文是考察联合最佳逼近的联合极小化序列,证明一些联合最佳逼近的存在定理。我们还给出了不动点定理在联合最佳逼近中的一个应用。 相似文献
46.
47.
Synthesis of the titanium silicalite TS-1 was first reported by Taramasso et al[1]in 1983. TS-1 has received considerable interest during the last decade because of its unique catalytic properties in oxidation reactions involving H2O2 as the oxidant. It is accepted that the extraframework Ti species in TS-1 favor the decomposition of H2O2and should be avoided. But in the present study, it was observed that there was a kind of Ti species inactive in both the oxidation reaction and the decomposition of H2O2. 相似文献
48.
49.
CO加氢合成C2含氧化合物Rh-Sm/SiO2催化剂的研究 总被引:3,自引:0,他引:3
使用加压下的CO加氢反应、程序升温还原(TPR)、吸附氢的程序升温脱附(H2-TPD)以及CO和H2吸附等技术,研究了Rh-Sm/SiO2催化剂上Sm促进剂对合成二碳含氧化合物的促进效应.结果表明,Sm加入到Rh/SiO2中使催化剂的活性和二碳含氧化合物的选择性显著提高,催化剂上的Sm3+不易被还原,Sm的加入起着提高Rh分散度的作用,使催化剂上CO和H2的吸附量增大,倾向于促进乙酸和乙醛的生成. 相似文献
50.
La2O3助剂对Co/AC催化剂上费-托合成反应性能的影响 总被引:5,自引:0,他引:5
通过改变稀土助剂La2O3的负载量,考察了La2O3助剂对活性炭负载Co基催化剂(Co/AC)上费-托合成性能的影响,并通过XRD, SEM, TPR和CO-TPD对催化剂进行了表征. 结果表明, La2O3的加入可提高催化剂的活性,降低产物中甲烷的选择性. 对于15%Co/AC催化剂,加入少量的La2O3(w(La)=0.7%~1.7%)可使CO转化率从27%升高到56%, 甲烷选择性从16.5%下降到7.8%,C5+选择性从55.4%升高到74.7%; 但加入过多的La2O3(w(La)=8.1%~12.4%)时,甲烷选择性反而升高. XRD和SEM结果表明, La2O3的加入提高了催化剂中Co的分散度. TPR和CO-TPD结果表明, La2O3与Co之间存在着相互作用,并使催化剂的还原度下降,尤其是La2O3负载量高的催化剂还原度下降更加明显,导致Co/AC催化剂上CO的高温吸附量的增加. 相似文献