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71.
注射成型塑化过程的可视化实验研究 总被引:1,自引:0,他引:1
利用自行开发的可视化实验装置对注射成型的塑化过程进行了系统的观察,着重讨论了不同的工艺条件对塑化性能的影响,同时借助示踪粒子对塑化过程的重要参数——固相速度进行了测量。实验所取得的数据为注射成型熔融模型的建立和对模型的验证提供了依据,同时也是注射螺杆优化设计的基础数据。 相似文献
72.
环形截面提升管内颗粒的运动行为 总被引:2,自引:0,他引:2
采用PDPA(phase Doppler particle analyzer system)及磷光颗粒示踪技术对环形截面提升管中颗粒的运动行为进行了研究。与传统提升管相比,环形截面提升管中颗粒速度分布的均匀性有所改善,其最高速度与最低速度之差变小。环形截面提升管最大速度值出现在相对径向位置φ=0.3-0.4处。与传统提升管相似,环形截面提升管内颗粒的轴向返混较严重,停留时间分布曲线存在较明显的拖尾,其中颗粒的轴向Peclet数与传统提升管也处于同一数量级范围。提升管床结构的改变并未显著改变其中气固流动的微观相结构,稀相与密相颗粒团微观两相仍然存在,这种微观相结构是造成颗粒严重返混的决定性原因:稀相中的颗粒与密相颗粒团中的颗粒分别造成了颗粒停留时间分布曲线的前峰与拖尾峰。 相似文献
73.
酚醛树脂注塑料的化学流变行为研究 总被引:1,自引:0,他引:1
利用Brabender流变仪,考察了酚醛树脂注塑料的化学流变特性,根据双阿累尼乌斯方程建立了酚醛树脂注塑料的化学流变模型。该模型与实验结果具有较好的一致性,利用该模型可以预测酚醛注塑料注塑所需要的工艺窗口,并能动态模拟整个注塑过程中的黏度变化。 相似文献
74.
Manika Varma‐Nair Christine A. Costello Karla S. Colle Hubert E. King 《应用聚合物科学杂志》2007,103(4):2642-2653
Gas hydrates formed in oil production pipelines are crystalline solids where hydrocarbon gas molecules such as methane, propane, and their mixtures are trapped in a cagelike structure by hydrogen‐bonded water molecules to form undesirable plugs. Methanol and glycol are currently used to prevent these plugs via thermodynamic inhibition. Small amounts of water‐soluble polymers may provide an alternate approach for preventing gas hydrates. In this study, we expand the fundamental understanding of water–polymer systems with differential scanning calorimetry. Nonfreezable bound water was used to quantify polymer–water interactions and relate them to the chemical structure for a series of polymers, including acrylamides, cyclic lactams, and n‐vinyl amides. For good interactions, the water structure needs to be stabilized through hydrophobic interactions. An increased hydrophobicity of the pendant group also appears to favor polymer performance as a gas hydrate inhibitor. Good inhibitors, such as poly(diethyl acrylamide) and poly(N‐vinyl caprolactam), also show higher heat capacities, which indicate higher hydrophobicity, than poor performers such as polyzwitterions, in which hydrophilicity dominated. The phase behavior and thermodynamic properties of dilute polymer solutions were also evaluated through measurements of the heat of demixing and lower critical solution temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2642–2653, 2007 相似文献
75.
Larvae and adults of the Colorado potato beetle,Leptinotarsa decemlineata (Say), are shown to have galeal gustatory cells that are highly sensitive to distillate of potato leaf extracts, (E)-2-hexen-1-ol, (E)-2-hexenal, and other saturated and unsaturated six-carbon alcohols. In larvae and adults, the sensory response patterns elicited by leaf homogenate, leaf distillate and a mixture of these two extracts differ in subtle ways. Beetle larvae feed most readily on Millipore disks treated with leaf homogenate and the mixture, but they did not feed on disks treated with leaf distillate. The differences in behavioral response and sensory input are used to derive a potential gustatory code that may stimulate different levels of feeding. This code may be disrupted by compounds present in nonhost leaves, thus leading to reduced feeding. Possible interactions of sapid leaf volatiles, amino acids, sugars, and potentially deterrent plant compounds are discussed. 相似文献
76.
锂电极表面膜的组成和阻抗行为 总被引:1,自引:0,他引:1
介绍了锂电池中锂电极的表面膜的组成和阻抗行为,并根据其表面膜的阻抗行为提出了电化学模型。 相似文献
77.
Nucleation effects of 2,2′‐methylene‐bis (4,6‐di‐tert‐butylphenyl) phosphate metal salts as a nucleating agent for isotactic polypropylene (iPP) were investigated with differential scanning calorimeter and polarized optical microscope, and their effects on mechanical, optical, and heat resistance properties of iPP were also studied. The results showed that monovalent metal salts of substituted aromatic heterocyclic phosphate such as sodium salt, lithium salt, and potassium salt had a good performance. With 0.2 wt % of sodium salt, lithium salt, or potassium salt incorporated into iPP, the crystallization peak temperature of iPP could be increased by 13.5, 13.6, and 15.0°C, respectively; the mass fraction of crystallinity of iPP could be increased by about 5%; and crystallization rate was enhanced increasingly. Meanwhile the tensile strength and flexural modulus of iPP could be increased by about 10 and 30%, respectively, and the clarity and heat distortion temperature of iPP could also be improved significantly. But bivalent and trivalent metal salts of substituted aromatic heterocyclic phosphate had little effect on properties of iPP. Meanwhile the morphology study showed that the addition of monovalent sodium salt could decrease the spherulite size of iPP significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4868–4874, 2006 相似文献
78.
The feeding and gustatory responses to ecdysone and 20-hydroxyecdysone were investigated in the silkworm,Bombyx mori. 20-Hydroxyecdysone reduced feeding response strongly in fourth- and fifth-instar larvae, whereas ecdysone had no effect on feeding response. 20-Hydroxyecdysone stimulated the R receptor, the receptor to feeding deterrents, to a great degree. By contrast, ecdysone was much less effective for stimulating the R receptor. These results indicate that ecdysone and 20-hydroxyecdysone have different effects on feeding response due to different interactions with mouthpart chemoreceptors. 相似文献
79.
M. S. J. Simmonds W. M. Blaney F. Delle Monache G. B. Marini Bettolo 《Journal of chemical ecology》1990,16(2):365-380
The antifeedant activity of a series of 21 chalcones, flavanes, and flavanones isolated from the generaLonchocarpus andTephrosia (Leguminosae) was assessed by behavioral and electrophysiological bioassays against larvae ofSpodoptera littoralis andS. exempta. The antifeedant activity is related to the molecular structure of the compounds, and possible modes of interaction with the insect taste receptors are discussed. 相似文献
80.
Spinose carbon nanotubes (SCNTs) are grown on silicon substrates covered with diamond-like carbon film and iron catalyst film (Fe/DLC/Si structure) by low frequency r.f. plasma-enhanced chemical vapor deposition (LFRF-PECVD). During the pre-treatment of the Fe/DLC/Si substrate, there are three processes happened, namely, iron film spalled to small islands, the DLC film graphitized, and the iron island reacted partially with the graphitized DLC (GDLC), which can be deduced from the Raman spectroscopy and SEM pictures. SCNTs film grew from C2H2---H2 mixture under low plasma density. The good contact of carbon nanotube with GDLC film was acquired by the accumulation of the graphite sheets and the reaction between the iron particles and GDLC film. The homogeneous spines with the length of approximately 15 nm and the thickness of <5 nm burgeoned from the defects at the wall of carbon nanotube and distributed uniformly, which were in fact thin bent or rolled-up graphite sheets. 相似文献