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101.
Fabrication and oxidation resistance of titanium carbide-coated carbon fibres by reacting titanium hydride with carbon fibres in molten salts 总被引:2,自引:0,他引:2
Using carbon fibres and titanium hydride as a reactive carbon source and a metal source, respectively, a protective titanium carbide (TiC) coating was formed on carbon fibres in molten salts, composed of LiCl-KCl-KF, at 750-950 °C. The structure and morphology of the TiC coatings were characterised by X-ray diffraction and scanning electron microscopy, respectively. The oxidation resistance of the TiC-coated carbon fibres was measured by thermogravimetric analysis. The results reveal that control of the coating thickness is very important for improvement of the oxidation resistance of TiC-coated carbon fibres. The oxidative weight loss initiation temperature for the TiC-coated carbon fibres increases significantly when an appropriate coating thickness is used. However, thicker coatings lead to a decrease of the carbon fibres' weight loss initiation temperature due to the formation of cracks in the coating. The TiC coating thickness on carbon fibres can be controlled by adjusting the reaction temperature and time of the molten salt synthesis. 相似文献
102.
103.
下第三系沙河街组第三段(E_(s3))长石砂岩经历了强烈的成岩作用,己进入晚成岩C的早期阶段。本文系统地研究了沙三段长石砂岩的成岩作用,各种自生矿物对储层孔隙性的控制,并探讨了阶状石榴石的自生成因,及各种自生矿物的形成温度与碎屑成岩演化的联系,描绘出该区成岩作用的时空分布特征,并认为储层孔渗质量与其中自生粘土的发育程度大体呈正相关关系。 相似文献
104.
本文以N-羟甲基丙烯酰胺、氯乙醇、三甲胺为原料合成了N-2(丙烯酰胺甲氧基)乙基三甲基氯化铵,这是目前国内尚没有开发的一种新型季铵盐,其共聚或均聚体分别是性能良好的纸干强剂或絮凝剂。本文以P—B实验设计法较全面考察了反应温度、反应时间、反应物配料比、硫酸加入量、碳酸氢钠加入量等诸因素对合成反应的影响,初步确定了影响反应产品收率的关键参数及其各自的较佳值,建立了在一定范围内适用的数学模型。 相似文献
105.
磷基FCC钝镍剂的开发及应用 总被引:1,自引:1,他引:0
工业试验表明 ,在催化裂化催化剂上的镍污染量高达 1%时 ,环境友好型磷酸盐钝镍剂仍能使汽油收率提高1% ,氢气产率和焦炭产率分别下降 35 %和 10 %以上 ,显示出良好的钝镍效果。结合轻油微反评价 (MAT)、TPR、XRD等实验方法和量子化学计算理论研究 ,阐明了磷基钝镍剂的钝镍机理 :在FCC再生条件 (约 70 0℃ ,氧化性气氛 )下 ,由于磷基钝镍剂热分解生成P2 O5,并与NiO反应生成NiP4O1 1 ,增加了Ni2 + 的能量最低空轨道 (LUMO)能量 ,降低了Ni2 + 在FCC(流化催化裂化 )反应条件 (约 5 0 0℃ ,还原性气氛 )下的还原度 ,有效抑制了Ni0 的强催化脱氢活性 ,从而达到钝镍的目的 相似文献
106.
107.
Physical properies of ion-conducting nanocomposites are reviewed. Special attention is paid to the change of the bulk characteristics of ionic salts in the nanocomposites due to the formation of the interface phases. The main thermodynamic reason of the formation of the nanocomposite as well as the stabilization of the interface phases is the adhesion energy a. At sufficiently high a values, the ionic salt tends to spread along the oxide surface, which leads to the formation of the nanocomposite on sintering. The adhesion is the result of the interface interaction and incorporates the stage of the specific adsorption of the interface ions. It leads to the formation of the double layer formed by the point defects in the interface region of the ionic salt. In the case of the strong adhesion, the structural reconstruction or the formation of the metastable interface phase takes place. Analysis of the experimental data shows that interface phases exist in composites AgI–Al2O3, MeNO3–Al2O3 (Me = Li, Na, K, Rb, and Cs), CsHSO4–SiO2, RbNO3–SiO2 and CsCl–Al2O3. Their structure may be either epitaxial crystalline, or amorphous. The thickness of the interface phase as estimated on the basis of the brick-wall model is about 3–4 nm. 相似文献
108.
The purpose of this study was to examine the effect of different concentrations of crude pig plasma transglutaminase (TGase) at 0, 0.05, 0.1, 0.2, 0.4 and 1.0% on the quality of low-salt chicken meat-balls. Yield, color, gel strength, microstructure and sensory evaluation were measured. The results showed that both the yield and gel strength of the meat-balls increased as TGase supplement increased (P<0.05) without any obvious effect on color. Scanning electron microscopy (SEM) indicated firmer and more regular gel structures with increasing TGase addition. Texture, juiciness and overall acceptability as judged by sensory evaluation were not statistically affected until the level of TGase reached 1.0% (P<0.05). 相似文献
109.
Transparency of Hydrophobic Vinyl Polymers Containing Small Amounts of Inorganic Chloride Salts 总被引:1,自引:0,他引:1
Termination of n-BuLi-initiated anionic polymerizations of vinyl monomers (i.e. styrene or butadiene) by chlorotrimethylsilae (CTMS) or methoxytrimethylsilane (MTMS) resulted in an opaque or transparent polymer product. Small amounts of salt (i.e. LiCl from CTMS- or Li(OCH3) from MTMS-terminated polymerization) generated during termination stage was presumably the cause of the transparency difference. To verify this, turbid solutions were prepared by mixing transparent polymers (prepared from a H2O-terminated anionic polymerization) with controlled amounts of LiCl in mixed tetrahydrofuran/cyclohexane (THF/CHE) solvents. Reduced viscosity (red) and particle size (determined from light scattering) of these turbid solutions were found to increase with polymer and LiCl content. On the contrary, both red and particle size decrease with increasing THF content of the mixed solvent. These results suggest that interactions between the LiCl/THF complex and the polymer chains are responsible for particle formation and hence turbid appearance of the solutions. Solution 7Li NMR spectra of the salt/polymer solutions indicated that polystyrene (PSt) has stronger interactions with LiCl as compared to polybutadiene (PBu), which resulted in a more homogeneously salt distribution in PSt than PBu as evaluated from the TEM micrographs of the corresponding bulk samples after solvent removal. A model with the included LiCl/THF complexes surrounded by the polymer coils was proposed to account for the resulting turbidity in solutions and in the bulk state. 相似文献
110.
The main problems arising in all far-from-equilibrium simulations come from temperature control. When local flows become important, it is not a simple matter to distinguish between the flow velocity and thermal motion. A way to bypass this problem is to control the temperature given by the configurational expression, which does not depend on velocity. The responses of molten NaCl to strong shear and strong constant and oscillating electric fields using kinetic and configurational thermostats are compared. The differences in response increase with the increase in the external perturbation, and in very strong fields one can observe striking structural differences. In the case of shear flow, the differences are of a general nature seen in all liquids (the appearance of a string phase with kinetic thermostats), while in an electric field they are peculiar to ionic fluids and are related to the degree of dissociation. Some structural properties can be deduced by evaluating the configurational temperature expression. 相似文献