全文获取类型
收费全文 | 284篇 |
免费 | 27篇 |
专业分类
电工技术 | 33篇 |
综合类 | 2篇 |
化学工业 | 90篇 |
金属工艺 | 7篇 |
机械仪表 | 10篇 |
建筑科学 | 7篇 |
能源动力 | 15篇 |
轻工业 | 22篇 |
石油天然气 | 1篇 |
无线电 | 24篇 |
一般工业技术 | 44篇 |
冶金工业 | 5篇 |
原子能技术 | 12篇 |
自动化技术 | 39篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 19篇 |
2017年 | 12篇 |
2016年 | 37篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 30篇 |
2012年 | 15篇 |
2011年 | 23篇 |
2010年 | 18篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
排序方式: 共有311条查询结果,搜索用时 31 毫秒
301.
Shota Yamamoto Hiroki Noguchi Asuka Takeda Ryosuke Arakaki Maimi Uchishiba Junki Imaizumi Saki Minato Shuhei Kamada Tomohiro Kagawa Atsuko Yoshida Takako Kawakita Yuri Yamamoto Kanako Yoshida Masafumi Kon Nobuo Shinohara Takeshi Iwasa 《International journal of molecular sciences》2022,23(15)
Polycystic ovary syndrome (PCOS) is frequently seen in females of reproductive age and is associated with metabolic disorders that are exacerbated by obesity. Although body weight reduction programs via diet and lifestyle changes are recommended for modifying reproductive and metabolic phenotypes, the drop-out rate is high. Thus, an efficacious, safe, and continuable treatment method is needed. Recent studies have shown that oxytocin (OT) reduces body weight gain and food intake, and promotes lipolysis in some mammals, including humans (especially obese individuals), without any adverse effects. In the present study, we evaluated the changes in endogenous OT levels, and the effects of acute and chronic OT administration on body weight changes, food intake, and fat mass using novel dihydrotestosterone-induced PCOS model rats. We found that the serum OT level was lower in PCOS model rats than in control rats, whereas the hypothalamic OT mRNA expression level did not differ between them. Acute intraperitoneal administration of OT during the dark phase reduced the body weight gain and food intake in PCOS model rats, but these effects were not observed in control rats. In contrast, chronic administration of OT decreased the food intake in both the PCOS model rats and control rats. These findings indicate that OT may be a candidate medicine that is efficacious, safe, and continuable for treating obese PCOS patients. 相似文献
302.
Yoshida Tomonori Muto Daiki Tamai Tomoya Suzuki Shinsuke 《Metallurgical and Materials Transactions A》2018,49(6):2463-2470
Metallurgical and Materials Transactions A - Porous aluminum alloy with aligned unidirectional pores was fabricated by dipping A1050 tubes into A6061 semi-solid slurry. The porous aluminum alloy... 相似文献
303.
Hiroki Eisawa Shun Ogawa Nobuhiro Yamazaki Kohki Maekawa Takahiro Yamaguchi Shota Sato Kazuma Shiota Takashi Yoshida 《Journal of Applied Glycoscience》2017,64(1):9
α-1,6-Glucosidase (isomaltase) belongs to glycoside hydrolase (GH) families 13 and 31. Genes encoding 3 isomaltases belonging to GH family 13 were cloned from filamentous fungi, Aspergillus oryzae (agl1), A. niger (agdC),and Fusarium oxysporum (foagl1), and expressed in Escherichia coli. The enzymes hydrolyzed isomaltose and α-glucosides preferentially at a neutral pH, but did not recognize maltose, trehalose, and dextran. The activity of AgdC and Agl1 was inhibited in the presence of 1 % glucose, while Foagl1 was more tolerant to glucose than the other two enzymes were. The three fungal isomaltases did not show transglycosylation when isomaltose was used as the substrate and a similar result was observed for AgdC and Agl1 when p-nitrophenyl-α-glucoside was used as the substrate. 相似文献
304.
Kazumi Nagata Shota Kato Akinori Jyo Masao Tamada Akio Katakai 《Reactive and Functional Polymers》2009,69(1):9-13
Reactive fibers having chemically fixed active ester were derived from chloromethylstyrene grafted polyethylene-coated polypropylene staple fiber and non-woven cloth. First, chlorine atoms in each fiber were substituted by mercapto groups, and the resulting fibers were reacted with N-hydroxymaleimide to obtain fibers containing chemically fixed N-hydroxysuccinimide moieties. These fibers were converted into reactive fibers having chemically fixed active ester by reaction with a model carboxylic acid (3-(2-bromophenyl)propionic acid) in the presence of a condensing reagent (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) in excess. Performances of both reactive fibers in the model amide synthesis were compared by their reaction with 2-phenylethylamine. Although the reactive non-woven cloth gave an amide contaminated with unknown organic impurities, the reactive staple fiber yielded highly pure product. Possible causes of this difference are discussed on the basis of SEM observation of both fibers. 相似文献
305.
Dr. Shuhei Takatani Dr. Tsuyoshi Tahara Dr. Mieko Tsuji Daiki Ozaki Nina Shibata Dr. Yoshinobu Hashizume Prof. Masaaki Suzuki Prof. Hirotaka Onoe Prof. Yasuyoshi Watanabe Dr. Hisashi Doi 《ChemMedChem》2021,16(21):3271-3279
The efficient synthesis of L-[5-11C]leucine and L-α-[5-11C]methylleucine has been investigated using a continuous two-step sequence of rapid reactions consisting of Pd0-mediated 11C-methylation and microfluidic hydrogenation. The synthesis of L-[5-11C]leucine and L-α-[5-11C]methylleucine was accomplished within 40 min with a decay-corrected radiochemical yield of 15–38 % based on [11C]CH3I, radiochemical purity of 95–99 %, and chemical purity of 95–99 %. The Pd impurities in the injectable solution measured using inductively coupled plasma mass spectrometry met the international criteria for human use. Positron emission tomography scanning after an intravenous injection of L-[5-11C]leucine or L-α-[5-11C]methyl leucine in A431 tumor-bearing mice was performed. As a result, L-α-[5-11C]methylleucine was found to be a potentially useful probe for visualizing the tumor. Tissue distribution analysis showed that the accumulation value of L-α-[5-11C]methylleucine in tumor tissue was high [12±3% injected dose/g tissue (%ID/g)]. 相似文献
306.
The effect of the addition of lithium trifluoromethanesulfonate (LiCF3SO3) on the linear viscoelastic properties, crystallization behavior, and mechanical properties of poly(lactic acid) (PLA) was studied. The glass transition temperature (Tg) was enhanced by adding LiCF3SO3, without any loss of transparency of the PLA. This was attributed to the ion-dipole interaction between the lithium cation and oxygen atom in the PLA carbonyl group. The interaction weakened at higher temperature. Consequently, the rheological terminal region was clearly detected, which suggested that the system possessed good melt-processability. The Young’s modulus and yield stress at room temperature were also enhanced by the addition of LiCF3SO3, although the toughness was reduced due to the brittle failure. Finally, the presence of LiCF3SO3 retarded the crystallization of PLA, because the segmental motion of the PLA chains was reduced. 相似文献
307.
Isao?TsuyumotoEmail author Yuichiro?Miura Masato?Nirei Shota?Ikurumi Takenori?Kumagai 《Journal of Materials Science》2011,46(16):5371-5377
Mixture of starch and amorphous sodium polyborate (SPB) is found to show high flame retardancy, when its aqueous solution
is deposited and dried on organic polymer materials such as polyethylene terephthalate (PET) nonwoven, rigid polyurethane
(RPU) foam, and polypropylene (PP) nonwoven. The PET nonwoven (10 mm thickness) and the RPU foam (10 mm thickness) coated
with the mixture endure the premixed flame of butane gas burner with length of 100 mm for more than 12 min. The PP nonwoven
(0.7 mm thickness) endures the nonpremixed flame with length of 65 mm in the 45 degrees Meckel burner test for more than 2 min.
The backside temperatures in the both tests remain below 130 °C. The thermal analyses and the SEM observation indicate the
mechanism that the SPB foam promotes the carbonization of starch and that the carbonized layer together with the SPB foam
insulate inside from oxygen and heat. 相似文献
308.
In this paper, the thermal convection field and its resonance phenomena in a square cavity with sinusoidal heat‐flux vibration were numerically investigated. As the angular velocity ω is changed, the thermal convection field at Pr = 0.71,Ra = 106 is found to be classified into 5 regions. In particular, the field has the local maximum relative amplitude of midplane Nusselt's number at ωc = 350, which corresponds to the angular velocity of internal gravity wave ωr estimated by a theoretical equation proposed by Thorpe. This shows that the local enhancement is induced by internal gravity wave resonance. Such correspondence is observed for Ra ≥ 105,Ra ≥ 106 for Pr = 0.71, 7.1, respectively. For these ranges of Ra we propose a correlation equation, a function of Pr and Gr only, to estimate the resonant angular velocity. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(5): 309–322, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20122 相似文献
309.
Yoshinari Sawama Kosuke Morita Shota Asai Masami Kozawa Shinsuke Tadokoro Junichi Nakajima Yasunari Monguchi Hironao Sajiki 《Advanced Synthesis \u0026amp; Catalysis》2015,357(6):1205-1210
The catalytic dehydrogenation of alcohols to carbonyl products is a green sustainable oxidation with no production of waste except for hydrogen, which can be an energy source. Additionally, a reusable heterogeneous catalyst is valuable from the viewpoint of process chemistry and water is a green solvent. We have accomplished the palladium on carbon (Pd/C)‐catalyzed dehydrogenation of primary alcohols to carboxylic acids in water under a mildly reduced pressure (800 hPa). The reduced pressure can be easily controlled by the vacuum controller of the rotary evaporator to remove the excess of generated hydrogen, which causes the reduction (reverse reaction) of aldehydes to alcohols (starting materials) and other undesirable side reactions. The present method is applicable to the reaction of various aliphatic and benzylic alcohols to the corresponding carboxylic acids, and the Pd/C could be reused at least 5 times.
310.
A Brønsted acid, trifluoromethanesulfonimide [HN(SO2CF3)2], was found to catalyze reductive β‐alkylation of pyrroles with carbonyl compounds and hydrosilanes. This metal‐free process features lower catalyst loadings compared to the original indium variant and exclusive generation of β‐alkylpyrroles.