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21.
为了探究典型长寿区大米有机硒的赋存形态与人体硒营养水平的关系,本文分析了江西典型长寿区大米中有机硒、谷蛋白硒、硒代蛋氨酸(Selenomethionine, SeMet)等的组成特征,并运用胃肠体外模拟法对大米硒的生物可利用度及其与各有机硒组分之间的相关关系进行了研究。结果表明,大米中的硒主要以有机形式(78.67 ± 13.52%)赋存,其中,53.73 ± 8.27%的有机硒为谷蛋白硒,且65%以上的谷蛋白硒可酶解消化为SeMet。大米硒的生物可利用度为55.58 ± 10.53%。大米谷蛋白中SeMet比例相对较高且易于被人体吸收利用,这可能与当地居民的健康长寿关系密切。不过,SeMet与大米可利用硒的相关系数仅为0.55。因此,未来有必要对大米中不同硒蛋白的代谢产物(如SeMet)进行研究。 相似文献
22.
Takashi Kitaguchi Yasumitsu Ogra Yuji Iwashita Kazuo T. Suzuki 《European Food Research and Technology》2008,227(5):1455-1460
Buckwheat (Fagopyrum esculentum Moench) and quinoa (Chenopodium quinoa Willdenow) are widely used as food ingredients. The nutritional characteristics of these plants, i.e., high contents of proteins
and amino acids suggest that selenium (Se) is preserved as selenoamino acid derivatives, in particular, selenomethionine (SeMet)
in proteins, similar to selenized yeast. Therefore, buckwheat and quinoa are expected to be a good nutritional source of Se.
Selenized buckwheat and quinoa were cultivated on Se-fortified soil using sparingly soluble Se salts, such as barium selenate
and barium selenite. Se concentration in the edible parts of these plants was determined, and Se extraction efficiency with
enzyme or alkali was evaluated. In addition, the chemical species of Se in the low molecular weight fraction of these plants
were determined by HPLC-ICP-MS. Total Se concentrations in the edible parts of selenized buckwheat and quinoa were 170.4 ± 2.9 μg/g
and 102.7 ± 2.4 μg/g wet weight, respectively. Thus, these selenized seeds were found to be Se accumulators. The results indicate
that Se in selenized buckwheat exists mainly as SeMet, while Se in selenized quinoa exists not only as SeMet but also as selenate
(Se(VI)) and non-protein forms. 相似文献
23.
本研究建立了一种顺序注射氢化物发生-原子荧光光谱法测定富硒鸡蛋中的Se含量的方法,同时讨论了共存离子的干扰情况。在最佳实验条件下,Se的检出限为0.082μg/L,加标回收率为94.2%~102.9%。 相似文献
24.
建立了原子荧光光谱法测定苹果醋中硒的分析方法,并对HNO3-HClO4和HNO3-H2O2两种消化体系进行了比较.方法线性范围0~200 μg/L,相关系数0.999 9,检出限分别为0.134 μg/L和0.159 μg/L,回收率分别为96.0%和102.0%. 相似文献
25.
Hanging copper amalgam drop electrode has been applied for trace determination of selenium by cathodic stripping analysis. Detection limit for Se(IV) as low as 0.25 nM (0.02 μg L−1) at deposition time (120 s) could be obtained. For seven successive determinations of Se(IV) at concentration of 5 nM relative standard deviation was 2.3% (n = 7). Interferences from selected metals and surfactant substances were examined. Absence of copper ions in sample solution causes easier optimization and makes method less vulnerable on contamination. The developed method was validated by analysis of certified reference materials (BCRs) and applied to selenium determinations in natural water samples, snow, mushrooms and ox liver. 相似文献
26.
本文研究了芝麻饼(渣)中含硒量、生物效能、生物效能、溶解性、分布及存在形式等性质 。用D型大柱凝胶电泳分析其可溶性蛋白硒络合分子量范围为21KD-30KD。提取条件效应综合预测数学模型为:Y1=0.4647A+10.0637C+36.8145D+0.1567E-32.7848,&2=0.0068A+0.0025B-0.4250D+).1670。 相似文献
27.
Cathodic reduction of Cd2+ on p-Se proceeds at low overpotential in the dark and results in bulk Cd, while the underpotential deposition is kinetically inhibited. Cadmium adlayer is photoelectrochemically deposited on illuminated electrode 0.7 V above E(Cd2+/Cd). The adlayer cathodic deposition under illumination proceeds with simultaneous formation of CdSe nanoparticles. Potentiodynamic electrochemical impedance spectroscopy has discriminated the two products of the photoelectrochemical reaction both by their potentials of anodic oxidation and by characteristic dependences of impedance on potential. Anodic oxidation of CdSe nanoparticles gives a sharp peak of real impedance in low frequencies close to the corresponding anodic current peak in cyclic voltammogram. The impedance peak appears below a threshold frequency ft. The latter separates two modes of diffusion in anodic dissolution of CdSe nanoparticles. The diffusion proceeds independently at different particles above ft and turns to cooperative mode below the threshold frequency. Due to this effect, information on spatial distribution of growing nuclei on electrode surface in early stages of electrodeposition can be obtained from potentiodynamic impedance spectra. 相似文献
28.
A novel methanol-tolerant oxygen-reduction catalyst, Iridium-selenium (Ir-Se) chalcogenide, was synthesized by chemical precipitation in an organic solvent. Auger electron spectroscopy (AES) analysis confirmed that the synthesized Ir-Se chalcogenide had a chemical formula of Ir4Se. This chalcogenide showed strong catalytic activity towards the oxygen reduction reaction (ORR) and a high methanol tolerance. It was found that most of the oxygen could be directly reduced to water through a four-electron pathway with less than 10% hydrogen peroxide (H2O2) being produced during the ORR. The improvement in catalytic activity of the Ir-Se chalcogenide in comparison with that of pure Ir might be attributed to the effect of a bimetallic interaction. 相似文献
29.
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