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61.
以库尔勒香梨为试材,研究0.10、0.20、0.30 mg/kg浓度1-MCP对香梨贮藏过程中果实品质和矿质营养的影响。结果表明:1-MCP结合保鲜袋和冷藏处理能够明显抑制果实质量损失,保持果实硬度,防止果实内总酸含量、可溶性固形物含量、Vc含量变化。其中,0.10 mg/kg 1-MCP结合MAP和冷藏处理能较好地保持细胞膜的完整性,抑制Vc含量变化,防止褐变;0.20 mg/kg 1-MCP结合保鲜袋和冷藏处理能较好地保持果实质量。此外,采用一定浓度的1-MCP处理有助于果实中P、Ca含量和N、Ca含量相关性的增长,0.10 mg/kg 1-MCP处理有助于P、Ca含量相关性的增长;0.20 mg/kg、0.30 mg/kg 1-MCP处理有助于N、Ca含量相关性的增长。 相似文献
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Xirali Mamtimin Aierken Aikebaierjiang Musitake Alifujiang Tuerhong Tuerxun Zaytungul Kurban Wan Fu Sun Ismayil Nurulla 《Journal of Polymer Research》2011,18(1):105-109
A new monomer (2-N,N-dimethylamino-4,6-Bis (2-thienyl)–pyrimidine) was synthesized and its homopolymer was successfully prepared by using Ferric
trichloride (FeCl3) as an oxidant. The structure of the polymer and monomer was fully characterized by 1H–NMR, FTIR, UV-vis, Fluorescent spectroscopy and X-ray diffraction pattern. The polymer gives rise to a band at λ
max = 391 nm. The polymer showed the PL spectrum, gave a peak at 507 nm.We have observed that the polymer was sensitive to inorganic
acids and the acidochromism behavior was investigated applying organic acid such as CF3COOH. The corresponding UV-Vis peaks were observed at 464 nm and 357 nm respectively. X-ray diffraction data shows that polymer
has a certain crystallinity. The polymer exhibited an [η] value of 0.26 dLg−1 at 25 °C in H2SO4 (w = 98%). 相似文献
66.
小波理论去噪方法有很多种,小波阈值去噪方法,理论较为成熟,算法更加简单,数值的稳定性高,去噪的效果好。软阈值函数方法和硬阈值函数方法去噪在实际应用中使用很广泛,但总有一些不足的地方,因为软、硬阈值函数自身的结构都有一定的缺陷。本人提出一种新的阈值函数,它有较好的光滑性,随着参数取值的变化,新阈值函数介于在软、硬阈值函数之间,而且表达式简单,计算方便。最后,在MATLAB环境下,对加入高斯白噪声的信号进行了去噪的仿真实验,结果表明:新阈值函数去噪方法好于软、硬阈值去噪方法。 相似文献
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《Food Control》2013,32(2):268-273
Quantitative differentiation of the live fraction of pathogens in raw food samples is highly critical from a public health risk perspective, as many studies have shown that under stress conditions major foodborne pathogens enter a viable but non-culturable (VBNC) state in which bacteria can remain for long periods of time and maintain the potential for virulence. The objective of this study was to evaluate the applicability of propidium monoazide (PMA) quantitative PCR (qPCR) and immunological methods for detection of Escherichia coli O157:H7 VBNC populations induced by low temperature on the surface of lettuce and spinach plants. The primer/probe set selected influenced the qPCR signal in mixtures with a defined ratio of viable and non-viable cells. The PMA qPCR used in a background of added dead pathogens and epiphytic bacteria gave a detection limit of 103 CFU/g leaf and a linear quantitative detection range of 5 log. During quantification of VBNC cells from lettuce and spinach samples there was a good correlation between the PMA qPCR results and viable counts detected by microscopy, showing that PMA qPCR gives an accurate indication of the VBNC population. However, the commercially available immunoassay methods used to detect Shiga-like toxin production and the O157 antibody in vegetable samples with no detectable culturable pathogen underestimated the number of samples contaminated with E. coli O157:H7 VBNC cells. Results indicate that PMA qPCR is a suitable technique for the detection and quantification of VBNC cells of foodborne pathogens in contaminated raw lettuce and spinach. 相似文献
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《Food chemistry》1986,22(1):17-25
Fresh and dry mature seeds of fifteen cultivars or lines of faba bean were compared with respect to their mono- and oligosaccharide contents, in an attempt to determine the possibilities for selection in a breeding programme on the basis of some chemical characteristics. The raffinose content of the whole dry seed ranged from 0·12% to 0·29%, the stachyose content between 0·46% and 1·02%, the verbascose content, the principal α-galactoside, from 0·82% to 1·61% on a dry matter basis. These components occurred in seeds with more than 30% of dry matter, while fructose, glucose and sucrose regularly decreased during seed development. 相似文献