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111.
磷酸铁(FePO4)是锂电池正极材料磷酸铁锂(LiFePO4)的核心前驱体,FePO4形貌及硫含量对合成的LiFePO4材料性能有重要影响。为得到类球形低硫FePO4产品,在传统液相沉淀法技术基础上做了改进优化,添加十六烷基三甲基溴化铵(CTAB)作为形貌助剂提高产品球形度,添加氨水作为配体形成磷酸铁铵配合物改善结晶过程,降低产品硫含量。结果表明:所制备的FePO4产品硫质量分数低,达到2.6×10 -5,形貌为均一的微米类球形颗粒,D50=11.4 μm,振实密度达到1.22 g/cm 3,有望成为制备高压实密度LiFePO4材料的核心前驱体。 相似文献
112.
用离子交换法能使硅酸盐激光玻璃机械强度增加2-3倍,激光强度增加3倍,从而弥补了自身热光系数较大的缺点。虽然玻璃在处理后,阈值稍微升高,效率稍有下降,但因允许输入更大的能量,使输出得到3倍的增加,说明了离子交换增强方法是成功的。 相似文献
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114.
A series of phosphorus‐containing, wholly aromatic thermotropic copolyesters from acetylated 2‐(6‐oxide‐6H‐dibenz〈c,e〉〈1,2〉oxa phosphorin‐6‐yl)‐1,4‐dihydroxy phenylene, p‐acetoxybenzoic acid, terephthalic acid, and isophthalic acid were prepared by melting polycondensation. The structure and basic properties of the polymers, such as the glass‐transition temperature (Tg), melting temperature (Tm), thermal stability, crystallinity, and liquid crystallinity, were investigated with Fourier transform infrared, elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis, wide‐angle X‐ray diffraction, and hot‐stage polarizing optical microscopy. The copolyesters had relatively high Tg values ranging from 183 to 192°C. The Tm values obtained from DSC curves for samples P‐20 and P‐25 were 290 and 287°C, respectively (where the number in the sample name indicates the molar fraction of the phosphorus‐containing monomer in the reactants). The initial flow temperatures of other samples observed with hot‐stage polarizing microscopy were 271–290°C. The 5% degradation temperatures in nitrogen ranged from 431 to 462°C, and the char yields at 640°C were 41–52%. All the copolyesters, except P‐40, were thermotropic and nematic. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1278–1284, 2002 相似文献
115.
Development of structures in new cycloolefin copolymers (COCs) of ethylene–norbornene (E–NB) and ethylene–tetracyclododecene (E–TD) of different NB/TD compositions were investigated under uniaxial elongational flow. For E–NB copolymer, which has multiblock sequences, a shoulder in WAXD at 0.76 nm was evident besides its amorphous halo, and the relative intensity of the peak increased with increasing comonomer content (NB). The appearance of a new peak for E–TD copolymer, and a relatively higher intense peak for E–NB copolymer at the same position of 0.76 nm, indicated that local ordering of the segments occurred when the COC was subjected to uniaxial flow. A lower comonomer composition of elongated COC, at a constant Hencky strain rate, exhibited two Tg values, whereas a higher composition showed a single Tg. Both local ordering and segmentization occurred in low comonomer content COCs but only local ordering occurred in higher comonomer content COCs. Both the shear viscosity and roll processing experiments exhibited similar phenomena of segregation. A model is proposed to illustrate the structure of COC after uniaxial elongation/deformation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3421–3427, 2004 相似文献
116.
发展玻璃纤维产业纺织品 总被引:2,自引:0,他引:2
本文层层深入地介绍产业用纺织品发展与应用、玻璃纤维纺织品发展与应用,以及它们的国内外概况并给出一些意见,以期待玻璃纤维产业纺织品有更好的发展. 相似文献
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118.
North Carolina rock phosphate (NCRP) (highly carbonate—substituted apatite) was ground to produce three samples with different particle size distributions. The effectiveness of these fertilizers was compared with the effectiveness of superphosphate in a field experiment and three glasshouse experiments using lateritic soils from south-western Australia. Non-reactive Queensland rock phosphate (low carbonate-substituted apatite from the Duchess deposit) was also used in the pot experiments. Bicarbonate-soluble phosphorus extracted from the soil is widely used in Western Australia to predict plant yields from previously-applied fertilizer dressings. For both field and pot experiments bicarbonate-extractable phosphorus (soil test value) was measured and related to subsequent plant yields.As calculated from the initial slope of the relationship between yield and the level of P applied, finely powdered NCRP was about 5–32% as effective as freshly-applied superphosphate in the year of application and also for two years after application in the field experiment, and for two successive crops in the three pot experiments. For both field and pot experiments, finely powdered NCRP, was at best, 1.5–2.0 times as effective as granular NCRP. Relative to freshly-applied superphosphate, the effectiveness of rock phosphates usually decreased with increasing level of application.For each of the crops in the field experiment, the relationships between yield and phosphorus content of plants (i.e. internal efficiency curves) were similar for all fertilizers. Thus the low effectiveness of the rock phosphates relative to superphosphate was solely due to much less phosphorus being taken up by plants. By contrast, in the pot experiments internal efficiency curves differed for different fertilizers. This is attributed to differences in the rate of phosphorus uptake by plant roots during the early stages of plant growth.For both field and pot experiments, soil test calibrations (the relationship between yield and soil test value) differed for rock phosphates and superphosphate. For superphosphate, soil test calibrations also differed for the three different years after the initial application of this fertilizer in the field experiment. For the second crop in the pot experiment, soil test calibrations differed for superphosphate applied at different times (before the first and the second crop). These results point out the difficulty of applying soil testing procedures to soils that have experienced different histories of fertilizer application. 相似文献
119.
120.
研究了玻璃颗粒在乙醇溶液中对Ca^2 的选择吸附,反转了玻璃颗粒在乙醇中的荷电性质,使玻璃颗粒能够在乙醇中与羟基磷灰石发生共沉积。讨论了不同离子浓度下电泳沉积的沉积量与沉积电流的变化情况,并以此对Ca^2 在电泳沉积中的作用进行了分析。实验结果证实:悬浮液中Ca^2 或吸附到玻璃颗粒上,改变其荷电性质;或留在溶液中,作为电泳沉积过程中电流的主要承载者。离子浓度对电泳沉积的效果有重要的影响,离子浓度太低或太高都易使涂层出现缺陷。分析了不同沉积条件下电泳沉积所得涂层的各种缺陷及其成因。 相似文献