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991.
George Ting-Kuo Fey P. Muralidharan Cheng-Zhang Lu Yung-Da Cho 《Electrochimica acta》2006,51(23):4850-4858
An enhanced electrochemical performance LiCoO2 cathode was synthesized by coating with various wt.% of La2O3 to the LiCoO2 particle surfaces by a polymeric method, followed by calcination at 923 K for 4 h in air. The surface-coated materials were characterized by XRD, TGA, SEM, TEM, BET and XPS/ESCA techniques. XRD patterns of La2O3-coated LiCoO2 revealed that the coating did not affect the crystal structure, α-NaFeO2, of the cathode material compared to pristine LiCoO2. TEM images showed a compact coating layer on the surface of the core material that had an average thickness of about ∼15 nm. XPS data illustrated that the presence of two different environmental O 1s ions corresponds to the surface-coated La2O3 and core material. The electrochemical performance of the coated materials by galvanostatic cycling studies suggest that 2.0 wt.% coated La2O3 on LiCoO2 improved cycle stability (284 cycles) by a factor of ∼7 times over the pristine LiCoO2 cathode material and also demonstrated excellent cell cycle stability when charged at high voltages (4.4, 4.5 and 4.6 V). Impedance spectroscopy demonstrated that the enhanced performance of the coated materials is attributed to slower impedance growth during the charge-discharge processes. The DSC curve revealed that the exothermic peak corresponding to the release of oxygen at ∼464 K was significantly smaller for the La2O3-coated cathode material and recognized its high thermal stability. 相似文献
992.
Ultrafine lithium ion conducting La2/3−xLi3xTiO3 (x = 0.11, LLT) powder was synthesized by a simple polymerizable complex method based on the Pechini-type process. The formation mechanism, homogeneity and microstructure of the samples were investigated by thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analysis indicated the formation of pure perovskite-type phase. The powder synthesized at a temperature as low as 900 °C in a much shorter time than solid-state reaction method was well crystallized. The lithium ion conductivity of the LLT ceramics sintered at 1200 °C was found to be 9 × 10−4 S/cm at room temperature. 相似文献
993.
E. A. Levashov A. S. Rogachev V. V. Kurbatkina Yu. K. Epishko N. A. Kochetov 《International Journal of Self-Propagating High-Temperature Synthesis》2007,16(4):218-224
Biocompatible composites (Ti, Ta)C
x
+ Ca3(PO4)2 for deposition of nanofilms onto load-bearing implants by ion-plasma sputtering were prepared from Ti + Ta + C + Ca3(PO4)2 mixtures by forced SHS compaction. The effect of Ta + C addition to green mixtures (characterized by parameter z) on the structure/phase formation in combustion products was explored. The addition of tantalum and carbon was found to have
little or no influence on the burning velocity U and combustion temperature T
c. Two thermal spikes exhibited by thermograms were associated with the occurrence of two consecutive reactions leading to
formation of titanium and tantalum carbides. With increasing z, the grain size of (Ti, Ta)C was found to diminish, its relative density to decrease, while the hardness to markedly grow.
相似文献
994.
Electrochromic properties of electrochemically deposited and etched (EDE) WO3−x films have been investigated using voltammetry and nanogravimetry to elucidate the amount of residual stress associated with lattice polarization and deformation in WO3−x nanoparticles. The cathodic WO3−x deposition from pertungstic acid solution and unusual properties of the cathodic electroetching of the oxide in tetraethyl ammonium chloride solution are reported and elucidated on the basis of Electrochemical Quartz Crystal Nanogravimetry (EQCN) measurements. The stress enhanced resonant frequency shift was observed upon WO3−x film coloration. However, the stress enhancement appeared to be much lower (up to 4-6 times) than that measured for films synthesized by other methods. The stress reduction in WO3−x films under study has been attributed to the stress relaxing propensity of EDE film to suppress the compressive stress wave. A considerable isotopic effect has been observed in nanogravimetry of the H+ and D+ ion intercalation into WO3−x films. We have found that the isotopic effect is primarily due to the true mass loading difference between hydrogen and deuterium ions, for the same concentration of color centers (2.65 × 1021 cm−3), since EQCN frequency shifts associated with stress in the film for H+ and D+ are very close to each other. 相似文献
995.
以固体超强酸SO2-4/TiO2 WO3为催化剂,通过丁酮和1,2 丙二醇反应合成了丁酮1,2 丙二醇缩酮。探讨了SO2-4/TiO2 WO3对缩酮反应的催化活性,研究了酮醇摩尔比、催化剂用量、反应时间对产品收率的影响。实验表明,在n(丁酮)∶n(1,2 丙二醇)=1∶1 5,催化剂用量为反应物料总质量的0 7%,环己烷为带水剂,反应时间1 0h的优化条件下,丁酮1,2 丙二醇缩酮的收率可达85 7%。 相似文献
996.
997.
1-(5-乙基-1,3,4-噻二唑基)-3-苯基硫脲的合成及生物活性 总被引:12,自引:0,他引:12
研究了 1 - ( 5 -乙基 - 1 ,3,4-噻二唑基 ) - 3-苯基硫脲的合成及抗菌活性。以 5 -乙基 - 2 -氨基 - 1 ,3,4-噻二唑和异硫氰酸苯酯为原料 ,在十六烷基三甲基溴化铵催化下 ,合成 1 - ( 5 -乙基 - 1 ,3,4-噻二唑基 ) - 3-苯基硫脲 ,找到了较好的合成工艺条件 ,结果表明 :5 -乙基 - 2 -氨基 - 1 ,3,4-噻二唑和异硫氰酸苯酯的摩尔比为 1∶ 1 .8,乙腈为溶剂 ,水浴加热回流 4.0 h,十六烷基三甲基溴化铵为 2 g,1 - ( 5 -乙基 - 1 ,3,4-噻二唑基 ) - 3-苯基硫脲的产率为 5 9.76%。同时发现 1 - ( 5 -乙基 - 1 ,3,4-噻二唑基 ) - 3-苯基硫脲有较强的抗菌活性 相似文献
998.
The destruction of hydrocarbon in deep carbonate diagenetic environment is one of problems on the formation of oil and gas. Organic-inorganic reactions in the process of TSR(Thermochemical Sulfate Reduction) are the main reason to make disappearance of the hydrocarbons. The work in this field has often been the subject of much research work in recent years. In this paper, the thermodynamics of CH4-CaSO4 and H2S-Fe2O3 systems is discussed to investigate the possibility of reactions. It is found that these two reactions can proceed spontaneously.Increasing temperature is favorite for CH4-CaSO4 system but disfavorite for H2S-Fe2O3 system. Thermal simulation experiments were carried out using autoclave at high temperature and high pressure. The properties of the products were characterized by microcoulometry, FT-IR and XRD methods. On the basis of the experimental data, a reaction kinetic model is developed and kinetic parameters are determined. 相似文献
999.
1000.
1-苯基-3-甲基-4-咔唑-N-丁基-4-苯甲酰基呲唑啉-5-酮的合成及其光谱研究 总被引:4,自引:0,他引:4
在苯和50%NaOH介质中,80℃时1,4-二溴丁烷与咔唑(CZ)反应,生成N-溴丁基咔唑(BCZ)。在丙酮和K2CO2介质中,50℃时N-溴丁基咔唑与1-苯基-3-甲基-4-苯甲酰基吡唑啉-5-酮(PMBP)反应,生成1-苯基-3-甲基-4-咔唑-N-丁基-4-苯甲酰基吡唑啉-5-酮(PMCBP),详细研究了CZ,BCZ,PMBP和PMCBP的UV和IR光谱.在氯仿中PMCBP对Nd(Ⅲ)的萃取率是PMBP的2.3倍,PMBP-Nd(Ⅲ)配合物无荧光,但PMCBP-Nd(Ⅲ)配合物有很强的荧光,说明PM-CBP是Nd(Ⅲ)的优良荧光试剂。 相似文献