全文获取类型
收费全文 | 189篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
综合类 | 1篇 |
化学工业 | 103篇 |
金属工艺 | 5篇 |
机械仪表 | 2篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 13篇 |
石油天然气 | 4篇 |
无线电 | 5篇 |
一般工业技术 | 37篇 |
冶金工业 | 13篇 |
自动化技术 | 10篇 |
出版年
2023年 | 2篇 |
2022年 | 20篇 |
2021年 | 34篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有200条查询结果,搜索用时 410 毫秒
41.
Boris A. Katsnelson Ivan N. Chernyshov Svetlana N. Solovyeva Ilzira A. Minigalieva Vladimir B. Gurvich Irene E. Valamina Oleg H. Makeyev Renata R. Sahautdinova Larisa I. Privalova Anastasia E. Tsaregorodtseva Artem V. Korotkov Eugene A. Shuman Vladimir G. Panov Marina P. Sutunkova 《International journal of molecular sciences》2021,22(1)
Rats were exposed to nickel oxide nano-aerosol at a concentration of 2.4 ± 0.4 µg/m3 in a “nose only” inhalation setup for 4 h at a time, 5 times a week, during an overall period of 2 weeks to 6 months. Based on the majority of the effects assessed, this kind of exposure may be considered as close to LOAEL (lowest observed adverse effect level), or even to NOAEL (no observed adverse effect level). At the same time, the experiment revealed genotoxic and allergic effects as early as in the first weeks of exposure, suggesting that these effects may have no threshold at all. 相似文献
42.
Polystyrenes with different stereoregularities were obtained by initiation of the styrene anionic polymerization via alkyllithium/alkali metal alkoxide systems in hydrocarbon media. Depending on the nature of the metal alkoxide associated to alkyl lithium and more particularly of the alkali metal counter-ion (lithium, sodium, potassium), the synthesis of polystyrene exhibiting predominantly isotactic or syndiotactic triads was achieved. The use of soluble metal alkoxide improves the stereospecificity as well as the initiation efficiency with respect to initial alkyl lithium. The contribution of propagating active species yielding a single type of polymer chains with stereochemical irregularities is supported by the solubility characteristics of the isotactic and syndiotactic rich polystyrenes. A reaction mechanism involving the formation of bimetallic complexes between the alkyllithium and the alkali metal alkoxide and ligand-metal exchanges is discussed. 相似文献
43.
Gulmira Zhumadilova Marziya Yashkarova Larisa Bimendina Sarkyt Kudaibergenov 《Polymer International》2003,52(6):876-882
Novel linear and crosslinked copolymers of acrylic acid and Schiff base, containing the amine groups in the main chain and the carboxylic groups in the side chain, have been synthesized by the Michael addition reaction followed by radical copolymerization. The copolymers that exhibited poly(ampholyte–electrolyte) behaviour were used to prepare complexes by reaction with anionic (poly(acrylic acid), poly(styrene sodium sulfonate)), cationic (polyethyleneimine, poly(hexamethylene guanidine)) and non‐ionic (poly(N‐vinylpyrrolidone), poly(ethylene glycol), poly(vinyl alcohol)) polymers. The influence of external factors, such as solvent quality, temperature, pH and ionic strength, on phase (coil–globule) and volume (swelling–collapse) transitions has been studied. © 2003 Society of Chemical Industry 相似文献
44.
Galina A. Kovalenko Larisa V. Perminova Dmitry V. Krasnikov Vladimir L. Kuznetsov 《Journal of Porous Materials》2018,25(4):1017-1026
A macroporous carbon aerogel (MCA) was produced by in situ synthesis of multi-walled carbon nanotubes (CNTs) via catalytic high-temperature decomposition of ethylene over the supported Fe:Co catalyst. A three-dimensional framework of ball-shaped MCA granules was formed by chaotic interlacing of growing CNTs and mechanical strength of the granules was high enough for their promising application in heterogeneous processes, in particular, bioconversion of fatty acids. The macroporous carbon aerogel was investigated as a novel support for adsorptive immobilization of an enzyme—Thermomyces lanuginosus lipase, followed by preparation of the lipase-active heterogeneous biocatalysts. It was found that the efficient and tight adsorption of the lipase on MCA occurred due to hydrophobic interactions. The amount of the lipase adsorbed in one dense adsorptive layer was equal to 110 mg per 1 g of the carbon aerogel. The lipase adsorbed in the 1st adsorptive layer possessed the maximum activity, 700–800 U/mg. The lipase-active heterogeneous biocatalysts were studied in the periodic processes of hydrolysis of emulsified triglycerides (tributyrin), interesterification of vegetable oil with ethyl acetate, and esterification of fatty acids (butyric C4:0, capric C10:0, and stearic C18:0) with isopentanol. It was found that T. lanuginosus lipase lost significantly its enzymatic activity during adsorption on the carbon aerogel; possible causes of the negative effect of such immobilization were discussed. The specific activity of the adsorbed lipase, as well as activity and stability of the biocatalysts depended foremost on the type of the reaction performed. The maximum activities of the biocatalysts were determined to be approximately 75·103 and 2.5 U/g in tributyrin hydrolysis (aqueous media) and esterification of fatty acid (non-aqueous media), respectively. Stability of the biocatalysts was very high in the esterification reaction due to accumulation of essential water inside MCA. The lipase-active biocatalysts carried out the synthesis of isopentyl caprinate in organic solvents (hexane?+?diethyl ether) for several 100 h at 40 °C. 相似文献
45.
The main tool for conflict resolution (equilibration) is the equilibrium strategy. Among the torrent of publications in this field, including the seven Nobel prize winners of 1994–2012, the Nash equilibrium is the fundamental one. Such equilibrium. however, does not necessarily exist. In this case, it is only natural to introduce a new notion of equilibrium, that of Berge. It was discussed in the paper which established existence of the Berge equilibrium in the mixed strategies and proposed sufficient conditions reducible to determination of the saddle point of a special Germeier convolution of the gain functions. 相似文献
46.
47.
48.
Due to the limitations of the carrying capacity approach a level of service approach is advanced for recreation planning in outdoor settings. This paper is the first to apply this approach to a concerete realworld setting, picnics in two forests in Israel. To this end a survey was conducted among visitors to the two forests. The survey serves to elicit the factors that determine the level of satisfaction visitors derive from picnics in these sites, and the relative importance of these factors. On this basis the tolerance range of visitors for the various dimensions is elicited, using the site based method to identify the upper level of the range and the generic method to identify the lower extremity of the range. By relating the perceived level in each site to the tolerance range the level of service for each site is computed. The results show that the level of service approach is indeed applicable to concrete cases, and that it provides practical insights to planners at both the site level and the regional level, where it can serve as a tool for prioritizing resource allocation among sites. However, there is a need for further extensive experimentation with this method, both to assess whether it can be used to prioritize among sites where different activities take place, and to further substantiate the methodology used to elicit and calculate the levels of service. 相似文献
49.
Sandipan Maiti Hadar Sclar Rosy Sharma Noam Vishkin Miryam Fayena-Greenstein Judith Grinblat Michael Talianker Larisa Burstein Nickolay Solomatin Ortal Tiurin Yair Ein-Eli Malachi Noked Boris Markovsky Doron Aurbach 《Advanced functional materials》2021,31(8):2008083
The active role of alumina, pentalithium aluminate (Li5AlO4, Li-aluminate), and pentasodium aluminate (Na5AlO4, Na-aluminate) as the surface protection coatings produced via atomic layer deposition on Li and Mn-rich NCM cathode materials 0.33Li2MnO3·0.67LiNi0.4Co0.2Mn0.4O2 is discussed. A notable improvement in the electrochemical behavior of the coated cathodes has been found while tested in Li-coin cells at 30 °C. Though all the coated cathodes demonstrate enhanced electrochemical cycling and rate performances, Na-aluminate coated cathodes exhibit exemplary behavior. Prolonged cycling and rate capability testing demonstrate that after more than 400 cycles at 1 C rate, the uncoated cathode delivers only 63 mAh g−1, while those with alumina, Li-aluminate, and Na-aluminate coatings exhibit approximately two times higher specific capacities. The coated cathodes display steady average discharge potential and lower evolution of the voltage hysteresis during prolonged cycling compared to the uncoated cathode. Importantly, Na-aluminate coated cathode shows a lowering in gases (O2, CO2, H2, etc.) evolution. Post-cycling analysis of the electrodes demonstrates higher morphological integrity of the coated cathode materials and lower transition metals dissolution from them. The coatings mitigate undesirable side reactions between the electrodes and the electrolyte solution in the cells. 相似文献
50.
In this paper a new family of sorbents, specifically designed for ethanol sorption, is presented. The composites were synthesized by a dry impregnation of matrices with an aqueous solution of various salts. The ethanol sorption capacity of the composites, under conditions typical for adsorptive air conditioning cycle, has been measured by using an express method based on the Polanyi principle of temperature invariance. Results obtained show that the best novel composites have the ethanol sorption ability which is higher than that of known ethanol sorbents. The composite LiBr(30 wt.%)/SiO2 appears to show the highest sorption capacity and an uptake variation Δw = 0.56 and 0.40 g/g for air conditioning and ice making cycles, respectively. They are much larger than those obtained for conventional adsorbents. The correspondent cooling coefficient of performance (COP) was estimated to be 0.66 and 0.61, which is comparable with the COP of the best water sorbents. 相似文献