全文获取类型
收费全文 | 230篇 |
免费 | 3篇 |
专业分类
电工技术 | 23篇 |
化学工业 | 91篇 |
金属工艺 | 9篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
能源动力 | 3篇 |
轻工业 | 26篇 |
无线电 | 8篇 |
一般工业技术 | 26篇 |
冶金工业 | 4篇 |
原子能技术 | 11篇 |
自动化技术 | 26篇 |
出版年
2023年 | 1篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 14篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有233条查询结果,搜索用时 0 毫秒
51.
Tsuneo Kondo Takashi Watanabe Tomoko Ohshita Tadashi Kyuma 《Journal of the science of food and agriculture》1995,68(3):383-388
Faecal soluble lignin (FSL), extracted from the faeces of sheep that received orchardgrass and timothy, were compared with 90% dioxane-soluble lignins released by ball milling (MHL) and by subsequent enzymatic hydrolysis (EHL) from the same grasses. FSL contained much less carbohydrate and esterified p-coumaric and ferulic acids than MHL and EHL. Although no considerable differences were found in the yields of vanillin and syringaldehyde produced by nitrobenzene oxidation, the molar ratio of syringaldehyde to vanillin was higher for FSL than for MHL and EHL. Such differences in chemical properties among the lignin preparations were confirmed by 13C-NMR spectroscopy. FSL had a lower molecular size compared with MHL and EHL. Results indicated that syringyl-rich lignin fragments with less phenolic acid esters, probably depolymerisation products of the grass lignins, were released by digestion in sheep from the forage grasses. 相似文献
52.
Hano T Oshima Y Kinoshita M Tanaka M Mishima N Ohyama T Yanagawa T Wakamatsu Y Ozato K Honjo T 《Environmental science & technology》2007,41(4):1473-1479
This study investigates the adverse and persistent effects of ethinylestradiol (EE2) on mature gonads of transgenic olvas-GFPIST II-YI medaka (Oryzias latipes). The measurement of gonadal size calculating the GFP-fluorescent area was used as a technique that enabled monitoring gonads in living specimens by GFP fluorescence. First, mature medaka were exposed to EE2 (47.8-522 ng/L) for 4 weeks. The gonads showed a significant reduction of the GFP-fluorescent area and Gonadosomatic Index in males exposed to EE2 at >216 ng/L and females exposed at 522 ng/L. Histologically, males at all treatments exhibited testis-ova and additionally, high connective tissue prevalence at > or =216 ng/L. Next, mature male medaka were exposed to EE2 (43.7-473 ng/L) for 3 weeks and allowed to depurate for 6 weeks, to investigate persistent effects of EE2. Continuous gonad observation showed that GFP began to decline 3 weeks after initial exposure to > or =215 ng/L. After depuration, the gonad's fluorescent areas gradually recovered, with no statistical difference at the end of the depuration period; normal spermatogenesis was present in these individuals. Alterations in GFP fluorescence clearly indicate the condition of the gonad in transgenic medaka and this strain showed a facilitated screening fish model to detect the adverse effects on the gonad by estrogenic chemicals. 相似文献
53.
The cDNAs encoding the zeta class of glutathione S-transferases (GSTs) (GSTZs), which are multifunctional enzymes, were cloned from Arabidopsis thaliana L. and three lines of Brassica napus L. by RT PCR, and named AtGSTZ for A. thaliana ecotype Columbia gll, and BnGSTZ-A, BnGSTZ-B and BnGSTZ-C for B. napus cv. Shan 2A, Shan 213 and Ken C1, respectively. Sequence analysis revealed that the sequences of Shan 2A and Shan 2B were identical, and Ken C1 was different only in 3.8% of the sequence. Comparison of these sequences with published sequences in GeneBank showed that the sequences of the Brassica species were unpublished. The cDNAs were then inserted into two vectors for in vivo expression in Escherichia coli and in vitro expression in a wheat-germ cell-free protein synthesis system. All GSTZs were well expressed both in vivo and in vitro as an enzymatically active form, showing that all of them had both dichloroacetic acid dechlorinating and maleylacetone isomerase activities. 相似文献
54.
55.
56.
Masuhiro Tsukada Takayuki Arai Giuliano Freddi Tsuneo Imai Nobutami Kasai 《应用聚合物科学杂志》2001,81(6):1401-1409
The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001 相似文献
57.
Roxana Irimescu Kiyomi Furihata Kazuhiko Hata Yugo Iwasaki Tsuneo Yamane 《Journal of the American Oil Chemists' Society》2001,78(3):285-290
A highly efficient enzymatic method for the synthesis of regioisomerically pure 1,3-dicapryloyl-2-docosahexaenoyl glycerol
(CDC) in two steps was established. 2-Monoglyceride (2-MG) formation by ethanolysis of tridocosahexaenoylglycerol (DDD) with
immobilized Candida antarctica lipase (Novozym 435) as catalyst was the key step of the synthesis. CDC was finally obtained by reesterification of 2-MG
with ethylcaprylate (EtC) catalyzed by Rhizomucor miehei lipase (Lipozyme IM). The regiospecificity of Novozym 435 depended on the type of reaction and the initial composition of
the reaction medium. It displayed strict 1,3-regiospecificity for ethanolysis at a high excess of ethanol in the reaction
mixture although it displayed no regiospecificity in transesterification and esterification reactions. The highest yield of
CDC (85.4%) was obtained by ethanolysis at a 4∶1 weight ratio of ethanol/DDD for 6 h followed by reesterification at a 20∶1
molar ratio of EtC/initial DDD for 1.5 h. The regioisomeric purity of CDC was 100%. Good results were obtained also for the
synthesis of 1,3-dicapryloyl-eicosapentaenoylglycerol (CEC) by the same method: 84.2% yield and 99.8% regioisomeric purity
at the same reactant ratios as above. The yield of the reesterification step and the regioisomeric purity of the product were
influenced by the molar ratio of the reactants for both CDC and CEC syntheses: higher excess of EtC favored higher yields
and regioisomeric purity of the products. 相似文献
58.
Keiko Takano Maki Mihashi Tsuneo Hirano 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(2):283-299
Abstract Mechanism of C60 formation from naphthalenes was studied by quantum chemical calculations. a patch up process of T-shape dimerization of naphthalenes followed by the intramolecular ring fusion, all through radical reactions, was proposed for a possible mechanism for the C60 formation from naphthalenes. the reaction barrier was found to be less than 60-70 kcal/mol for each reaction step in this mechanism. 相似文献
59.
60.
Keiko Takano Maki Mihashi Tsuneo Hirano 《Fullerenes, Nanotubes and Carbon Nanostructures》1998,6(2):283-299
Mechanism of C60 formation from naphthalenes was studied by quantum chemical calculations. a patch up process of T-shape dimerization of naphthalenes followed by the intramolecular ring fusion, all through radical reactions, was proposed for a possible mechanism for the C60 formation from naphthalenes. the reaction barrier was found to be less than 60-70 kcal/mol for each reaction step in this mechanism. 相似文献