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71.
Monomer acrylic acid (AA) and initiator azo‐bis(isobutyronitrile)were carried into Antheraea pernyi silk fibroin (SF) fibers using supercritical CO2 as a solvent and carrier, followed by free radical polymerization at a suitable temperature, resulting in PAA/SF blends. The binary system of CO2/AA and the ternary system of CO2/AA/AIBN systems were studied. Different impregnation conditions, such as time, pressure, and concentration of AA in the fluid phase on mass uptake, were studied. Fourier transform infrared spectroscopy and X‐ray diffraction results confirmed that PAA was indeed present in the silk and that there were intermolecular hydrogen bonds between PAA and SF. According to thermogravimetry and DTG, blending with PAA could enhance the thermal stability of SF slightly. The water retention values indicated that the hydrophilic nature of the fibers was improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 864–868, 2005 相似文献
72.
超临界CO_2萃取技术的工业应用 总被引:1,自引:0,他引:1
详细论述了超临界CO_2萃取技术在工业应用过程中遇到的工艺流程、装置设计与转产、能耗与安全等若干问题,提出了超临界CO_2萃取的工业化应用设计的总体要求。 相似文献
73.
74.
Adsorption of CO onto dehydrated cobalt-exchanged ZSM-5 zeolite was studied by CW-EPR techniques. It is shown that the reversible formation of a low spin carbonyl 1{Co(CO)
n
}7 adduct upon addition of carbon monoxide at p
CO>50–60 Torr involves significant change in the spin state of Co2+ from S=3/2 to 1/2. The spin Hamiltonian parameters of the adduct g
x
=2.222, g
y
=2.184, g
z
=2.011, |A
x
|=3.8 mT, |A
y
|=3.2 mT, |A
z
|=7.9 mT were determined by a computer simulation and further discussed in terms of the possible ground state and molecular structure. It is shown that the 1{Co(CO)
n
}7 cage complex exhibits a C2v symmetry with |z
2,2A1 ground state. 相似文献
75.
介绍了200kWCW超声电子束连续CO激光器(SSCO-EIL)开环实物模型的能量和光谱特征的实验研究结果,以及增加SSCO-EIL的输出功率,谱线选择性,Q-开关激光作用的数字计算结果,同时讨论了SSCO-EIL的特性对几种激光技术效率的影响,由于激光能量利用率的增加和能量成本的降低,SSCO-EIL拥有的无与伦比的能量和特有的特征,将大大拓宽激光技术的应用领域。 相似文献
76.
A fully continuous lab scale supercritical fluid extraction system has been designed, built and tested. The system continuously pumps carbon dioxide under supercritical conditions and soil slurry into a counter‐current contacting column. Delhi Loamy Sand, spiked with approximately 10 mg/g of naphthalene, was used as the testing soil. The soil slurry ranged from 0.0028 g dry soil per g slurry to 0.072 g/g. The operating temperature was 43°C and the operating pressure was 7.7 MPa. Near steady state, fully continuous flow was achieved with runs lasting as long as 2 h. All carbon dioxide samples contained measurable quantities of naphthalene and the measured mass transfer coefficients were as high as 4.6×10?4 s?1. 相似文献
77.
78.
79.
Changho Jung Hideyuki Tsuboi Michihisa Koyama Momoji Kubo Ewa Broclawik Akira Miyamoto 《Catalysis Today》2006,111(3-4):322-327
CO adsorption over Pd4 and Pt4 cluster supported by c-ZrO2(1 1 1) and CeO2(1 1 1) catalyst systems was investigated using periodic density functional method in order to clarify the support effect on CO activation. We found that the support increases the CO activation for bridge and three-fold sites but decreases for the atop site. Moreover, it was found that the support changes the site preference for the CO adsorption. Bridge site on both the Pt4/c-ZrO2 and Pt4/CeO2 show larger CO adsorption energies than those on the other sites while the atop site is energetically preferable on isolated Pt4 cluster. c-ZrO2 supported Pd shows the largest CO activation with large charge transfer from the catalyst to the CO molecule. This reveals that ZrO2 supported Pd can be a good catalyst for CO activation because of its higher probability to the three-fold site CO adsorption. We also found that positively charged M4 clusters on the support keep their strong electron-donating properties and have enough charge density to contribute to the activation of an adsorbed CO molecule by a charge transfer. 相似文献
80.
J. A. Rodriguez X. Wang P. Liu W. Wen J. C. Hanson J. Hrbek M. Pérez J. Evans 《Topics in Catalysis》2007,44(1-2):73-81
Synchrotron-based techniques (high-resolution photoemission, in-situ X-ray absorption spectroscopy, and time-resolved X-ray diffraction) have been used to study the destruction of SO2 and the water-gas shift (WGS, CO + H2O → H2 + CO2) reaction on a series of gold/ceria systems. The adsorption and chemistry of SO2 was investigated on Au/CeO2(111) and AuO
x
/CeO2 surfaces. The heat of adsorption of the molecule on Au nanoparticles supported on stoichiometric CeO2(111) was 4–7 kcal/mol larger than on Au(111). However, there was negligible dissociation of SO2 on the Au/CeO2(111) surfaces. The full decomposition of SO2 was observed only after introducing O vacancies in the ceria support. AuO
x
/CeO2 surfaces were found to be much less chemically active than Au/CeO2(111) or Au/CeO2−x
(111) surfaces. In a separate set of experiments, in-situ time-resolved X-ray diffraction and X-ray absorption spectroscopy were used to monitor the behavior of nanostructured {Au + AuO
x
}–CeO2 catalysts under the WGS reaction. At temperatures above 250 °C, a complete AuO
x
→ Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au
nanoparticles supported on rough ceria films or a CeO2(111) single crystal corroborate that cationic Auδ+ species cannot be the key sites responsible for the WGS activity at high temperatures. The active sites in {Au + AuO
x
}/ceria catalysts should involve pure gold nanoparticles in contact with O vacancies of the oxide. 相似文献