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1.
A route to synthesize ZSM‐5 crystals with a bimodal micro/mesoscopic pore system has been developed in this study; the successful incorporation of the mesopores within the ZSM‐5 structure was performed using tetrapropylammonium hydroxide (TPAOH)‐impregnated mesoporous materials containing carbon nanotubes in the pores, which were encapsulated in the ZSM‐5 crystals during a solid rearrangement process within the framework. Such mesoporous ZSM‐5 zeolites can be readily obtained as powders, thin films, or monoliths. 相似文献
2.
Tai-Shang ChenJia-Ming Chern 《Chemical engineering science》2002,57(3):457-467
The network reduction technique and the Bodenstein approximation of quasi-stationary behavior of reaction intermediates were systematically applied to derive general yield ratio and rate equations for multi-cycle reaction networks in homogeneous catalysis. Dual-cycle reaction networks connected by a linear pathway, multi-cycle networks stemming from the same intermediate, and single-cycle with arbitrary number of pathways between two intermediates were considered. The general yield ratio and rate equations derived in this study are applicable for most enzymatic reactions and for homogeneous catalytic reactions. Examples of homogeneous catalysis were used to illustrate the application of the general yield ratio and rate equations for network elucidation. 相似文献
3.
用于甲烷选择性氧化反应制甲醇的膜催化技术 总被引:5,自引:0,他引:5
朱立忠 《化学工业与工程技术》1997,18(1):11-14
研究了将甲烷选择性地一次氧化制取甲醇的膜催化技术。采用ZrO2-Y2O3陶瓷膜,在较温和的反应条件下(常压,460℃左右),可以将甲烷选择性地一次氧化成为甲醇。 相似文献
4.
5.
The effect of the hydride-forming intermetallic compound Zr2Fe on the aromatization of propane over high-silica zeolites of CVM type (Russian equivalent of ZSM-5) modified by Zn, Ga or Pt cations has been investigated. Aromatics yield and selectivity of aromatization are shown to increase essentially as a result of releasing hydrogen elimination by the intermetallic acceptor. The effect of hydrogen acceptor on propane conversion and product distribution appeared to be different depending on the composition of the catalyst used. Possible changes in the reaction mechanism in hydrogen removal conditions are discussed. 相似文献
6.
Esterification of acrylic acid with methanol by reactive chromatography: Experiments and simulations
The esterification of acrylic acid with methanol using Amberlyst 15 as a stationary phase has been investigated using a chromatographic reactor. Several experimental runs at various operating conditions have been conducted on a batch column. A classical reactive chromatography model including lumped kinetics, a linear driving force transport model and a heterogeneous kinetic model for the catalytic reaction has been developed. The additional dispersion of concentration fronts due to density gradient effects has been accounted for in the model. The model parameters have been determined in a fast and reliable way by directly fitting the batch column experiments. In general, a good agreement between experimental and calculated results is obtained. The evaluation of the covariance of the fitted model parameters reveals important insights about the system behavior.Based on the detailed batch column model, a complete model of a simulated-moving-bed reactor has been implemented and its optimal point of operation for the synthesis of methyl acrylate from acrylic acid has been determined. Particularly when considering the low-operating temperature, we can regard this process as a possible competition for current technologies. 相似文献
7.
Abdullahi Nuhu Jorge Soares Monica Gonzalez-Herrera Andrew Watts Ghulam Hussein Michael Bowker 《Topics in Catalysis》2007,44(1-2):293-297
We have investigated the adsorption and reaction of methanol with Au/TiO2 catalysts using a pulsed flow reactor, DRIFTS and TPD. The TiO2 (P25) surface adsorbed a full monolayer of methanol, much of it in a dissociative manner, forming methoxy groups associated
with the cationic sites, and hydroxyl groups at the anions. The methoxy is relatively stable until 250 °C, at which point
decomposition occurs, producing mainly dimethyl ether by a bimolecular surface reaction. As the concentration of methoxy on
the surface diminishes, so the mechanism reverts to a de-oxygenation pathway, producing mainly methane and water (at ~330 °C
in TPD), but also with some coincident CO and hydrogen. Au catalysts were prepared by the deposition-precipitation method
to give Au loadings between 0.5–3 wt %. The effect of low levels of Au on the reactivity is marked. The pathway which gives
methane, which is characteristic of titania, remains, but a new feature of the reaction is the evolution of CO2 and H2 at lower temperature (a peak is seen in TPD at 220 °C), and the elimination of the DME-producing state. Clearly this is associated
with the presence of Au and appears to be due to the production of a formate species on the surface of the Au component. This
formate species is mainly involved in the reaction of methanol with the Au/TiO2 catalysts which results in a combustion pathway being followed, with complete conversion occurring by ~130 °C. 相似文献
8.
H4SiW12O40-PAn催化剂催化合成苯甲醛乙二醇缩醛 总被引:11,自引:0,他引:11
报道了以自制的H4SiW12 O40 (硅钨酸 ) -PAn (聚苯胺 )为催化剂 ,通过苯甲醛和乙二醇为原料合成了苯甲醛乙二醇缩醛。实验表明 :合成苯甲醛乙二醇缩醛适宜反应条件为 :n(苯甲醛 ) /n(乙二醇 ) =1 /2 .0 ,催化剂用量为反应物料总质量的 1 .0 % ,环己烷为带水剂 ,反应时间 1 .0h。上述条件下 ,苯甲醛乙二醇缩醛的收率可达 86.7% . 相似文献
9.
10.
The removal of dichloromethane from atmospheric pressure air streams using plasma-assisted catalysis
Plasma-assisted catalysis was used for the destruction of 500 ppm of dichloromethane, CH2Cl2 (DCM), in gas streams of air using a non-thermal, atmospheric pressure plasma utilising a dielectric packed bed. The combination of plasma and catalyst gave improved destruction of DCM. Eight catalysts which including alumina, TiO2 and various zeolites were investigated with the finding that alumina in a one-stage reactor configuration and TiO2 and HZSM-5 in two-stage configurations gave the best DCM destructions. The sodium zeolites are capable of reducing by 50% the unwanted NOx by-products, formed by plasma processing in air. The nature of the catalyst is important in terms of the destruction efficiency, end-product selectivity and NOx reduction. 相似文献