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51.
For improvements of thermal stability and nonlinear optical (NLO) activity of chromophores, we newly synthesized a series of NLO chromophores incorporating aromatic benzoxazole unit as a π-conjugated bridge with various electron-withdrawing groups, such as nitrophenyl, nitrothiophene, nitrofuran, dicyanovinylphenyl, and nitrophenylethenyl group. Polymethylmethacrylate copolymers (PMBz) containing these benzoxazole chromophores were synthesized and their properties were investigated by thermogravimetry and ultraviolet-visible spectroscopy. The PMBz copolymers exhibited better thermal and ultraviolet stabilities than the corresponding copolymer with general stilbene chromophores (PMSt). Moreover, temporal stability of nonlinear optical coefficient (d33) of PMBz copolymer increased in comparison with that of PMSt. The copolymer with benzoxazole–nitrothiophene chromophores had the largest d33 value of 153 pm/V (at 1.064 mm) and nonresonant d33 calculated by the two-level model was 21.3 pm/V. 相似文献
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54.
探索了如何从空间对远紫外日辉辐射进行遥感观测,以便为检测高层大气状态提供新的监测方法。针对风云三号(FY-3)气象卫星有效载荷观测结果的数据处理,研究了利用140~180nm波段的LBH(Lyman-Birge-Hopfield)日辉辐射与OI 135.6nm日辉辐射进行O/N2反演的方法。通过研究这两个远紫外日辉观测信号的辐射特性,验证了二者的柱辐射率之比135.6/LBH与太阳活动呈相关关系。检验了太阳活动对O/N2反演曲线的影响,结果表明:太阳活动的变化会造成O/N2反演曲线之间存在比较大的偏差,因此在O/N2的反演技术中必须考虑如何消除太阳活动的影响。本文的工作为FY-3载荷仪器的O/N2图像反演技术的研究奠定了基础。 相似文献
55.
The sugar, organic acid, amino acid and fatty acid compounds of eight commercial pear cultivars were identified and quantified using high-performance liquid chromatography (HPLC) equipped with RI and UV detectors and gas-chromatography (GC) equipped with FID detector. The mineral composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed great quantitative differences in the composition of the pear cultivars. Fructose was the dominant sugar in the eight pear varieties, followed by glucose and sucrose, while malic acid was the principal organic acid. The C16:0, C18:0, C18:1, C18:2 and C18:3 fatty acids were clearly the most abundant fatty acids, and the C18 family comprised more than 70% of the total fatty acids content. Asparagine and serine were the principal amino acids. Potassium is the most abundant mineral, followed by magnesium and calcium. The results provide important information on how to make the best use of pear cultivars investigated for different uses, which is of significance for both technological research and processing practice. 相似文献
56.
Palgan I Caminiti IM Muñoz A Noci F Whyte P Morgan DJ Cronin DA Lyng JG 《International journal of food microbiology》2011,151(1):1-6
The combination of novel, non-thermal technologies for preservation purposes is a recent trend in food processing research. In the present study, non-thermal hurdles such as ultraviolet light (UV) (5.3 J/cm2), high intensity light pulses (HILP) (3.3 J/cm2), pulsed electric fields (PEF) (34 kV/cm, 18 Hz, 93 μs) or manothermosonication (MTS) (4 bar, 43 °C, 750 W, 20 kHz) were examined. The objective was to establish the potential of these technologies, applied individually or in paired sequences, to inactivate Escherichia coli and Pichia fermentans inoculated in a fresh blend of apple and cranberry juice. The shelf-life evaluation of selected non-thermally treated samples was conducted over 35 days and compared to pasteurised samples and untreated juices. All treatments applied individually significantly reduced (1.8-6.0 log cfu/ml) microbial counts compared to the untreated sample (p < 0.01). Furthermore, UV treatment produced significantly greater inactivation (p < 0.05) for E. coli compared to P. fermentans. Combinations of non-thermal hurdles consisting of UV or HILP followed by either PEF or MTS resulted in comparable reductions for both microorganisms (p ≥ 0.05) to those observed in thermally pasteurised samples (approx. 6 log cfu/ml). Thermally pasteurised samples had a shelf life exceeding 35 days, while that of UV + PEF and HILP + PEF-treated samples was 14 and 21 days, respectively. These results indicate that combinations of these non-thermal technologies could successfully reduce levels of E. coli and P. fermentans in apple and cranberry juice, although optimisation is required in order to further extend shelf life. 相似文献
57.
Yang Dongliang 《印染》1995,(10)
介绍了瑞士科莱恩(原山德士)公司的一些功能性整理剂如抗紫外线、卫生、拒油和防污等的近况及一些主要产品,并对其应用方法作了评述。 相似文献
58.
Víctor Falguera Jordi PagánSalvador Garza Alfonso GarvínAlbert Ibarz 《Food research international (Ottawa, Ont.)》2011,44(6):1580-1588
The effectiveness of ultraviolet irradiation in inactivating microorganisms has been known for decades. Nevertheless, in the processing of foodstuff other important issues must be considered, such as organoleptic or nutritional properties preservation. Ultraviolet irradiation constitutes an alternative to thermal treatment that is being studied and developed to obtain a better final product sensory quality, but without neglecting microbial safety. Moreover, it has been proved that this technology can be useful to decompose some toxins that are not affected by thermal processing. In this piece of work, the effect of UV irradiation on all of these contaminants and components of liquid food has been reviewed. 相似文献
59.
用紫外吸收光谱测定法测定了猪肉中蛋白质的含量,与凯氏定氨法对照,二者无显著性差异,前者准确度较高,重现性好,简单方便。 相似文献
60.
紫外光图谱在蔗汁澄清研究中的应用 总被引:1,自引:0,他引:1
利用紫外光图谱(λ=200~400nm)分析糖厂甘蔗汁中各种酚类物质、有机酸及其还原糖分解物对蔗汁色值的影响.结果表明:在弱酸性的蔗汁中,加入适量的碱性阳离子物质,可以吸附已经离解的酚类物质,从而提高蔗汁的澄清效果. 相似文献