首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   237篇
  免费   8篇
电工技术   1篇
化学工业   73篇
金属工艺   5篇
机械仪表   3篇
建筑科学   10篇
能源动力   8篇
轻工业   37篇
水利工程   2篇
石油天然气   2篇
无线电   19篇
一般工业技术   43篇
冶金工业   11篇
原子能技术   2篇
自动化技术   29篇
  2024年   10篇
  2023年   10篇
  2022年   14篇
  2021年   22篇
  2020年   7篇
  2019年   13篇
  2018年   10篇
  2017年   14篇
  2016年   14篇
  2015年   7篇
  2014年   10篇
  2013年   15篇
  2012年   9篇
  2011年   12篇
  2010年   10篇
  2009年   12篇
  2008年   9篇
  2007年   7篇
  2006年   6篇
  2005年   2篇
  2004年   7篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1999年   1篇
  1998年   10篇
  1997年   2篇
  1996年   3篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
排序方式: 共有245条查询结果,搜索用时 0 毫秒
21.
Factors affecting the electrical resistivity of soybean oil methyl ester (which is important in some industrial applications) were investigated by the addition of polar constituents [free fatty acids (FFA), water, phospholipids, monoglyceride, sterol, tocopherol, peroxides, and β-carotene] to aluminapurified soybean oil methyl ester (APSBOMe). Investigation of measuring conditions showed that reproducible results were obtained when the potential was greater than 25 V, and the charging time was greater than 10 s. The resistivity of APSBOMe increased logarithmically as temperature decreased linearly. FFA had little effect on resistivity. Saturation with water lowered the resistivity of APSBOMe much more than that of alumina-purified soybean oil (APSBO). Phospholipids reduced the resistivity significantly when added to dry ester, but the addition of water affected the resistivity of the samples containing phospholipids only slightly. Monoglyceride, sterol, tocopherol, and hydroperoxide affected the resistivity of dry methyl ester similarly, but only monoglyceride showed a significant synergistic effect with water. Diacylperoxide and β-carotene had little effect on the resistivity of the ester.  相似文献   
22.
23.
Soybean oil was hydrogenated with a carbon‐supported ruthenium catalyst (Ru/C) at 165 °C, 2 bar H2 and 500 rpm stirring speed. Reaction rates, trans isomer formation, selectivity ratios and melting behaviors of the samples were monitored. No catalytic activity was found for the application of 10 ppm of the catalyst, and significant catalytic activity appeared at >50 ppm of active catalyst. The catalyst concentration had an effect on the reaction rate of hydrogenation, but the weight‐normalized reaction rate constant (kc) was almost independent of the catalyst concentration at lower iodine values. Ru/C generated considerable amounts of trans fatty acids (TFA), including high amounts of trans 18:2, and also stearic acid, due to its very non‐selective nature. The selectivity ratios were found to be low and varied between 1.12 and 4.32 during the reactions. On the other hand, because of the low selectivity, higher slip melting points and solid fat contents at high temperatures were obtained than those for nickel and palladium catalysts. Another different characteristic of this catalyst was the formation (max 1.67%) of conjugated linoleic acid (CLA) during hydrogenation. Besides, CLA formation in the early stages of the reactions did not change very much with the lower iodine values.  相似文献   
24.
The dynamics of free radical polymerization of styrene and on-line control of temperature in a cooling jacketed batch polymerization reactor is investigated. The benzoyl peroxide initiator is introduced into the reactor once at the beginning of the reaction to obtain the desired monomer conversion and the desired average chain length in a minimum reaction time. The optimal constant set temperature, which is generally realized in industrial applications, and the set profile are used as two different optimal operating conditions. The temperature control of the polymerization reactor is achieved experimentally and theoretically. The control of nonlinear systems has progressed considerably, and various nonlinear process model based control techniques have appeared in the literature. The problem is how to tune the controller in order to obtain comparable closed loop responses. Generic model control (GMC) is applied and the performance of the control results are compared with the previously published control results.  相似文献   
25.
Targeting protein-protein interactions (PPIs) with small-molecule inhibitors has become a hotbed of modern drug development. In this review, we describe a new class of PPI inhibitors that block menin from binding to MLL proteins. Menin is encoded by the MEN1 tumor suppressor, but acts as an essential cofactor for MLL/KMT2A-rearranged leukemias. The most promising menin-MLL inhibitors belong to the thienopyrimidine class and have recently entered phase I/II clinical trials for treating acute leukemias characterized by MLL/KMT2A translocations or NPM1 mutations. As single agents, thienopyrimidine compounds eradicate leukemia in a xenograft models of primary leukemic cells belonging to the MLL-rearranged or NPM1-mutant subtypes. These compounds are well tolerated with few or no side effects, which is remarkable given the tumor-suppressor function of menin. The menin-MLL inhibitors highlight how leukemia patients could benefit from a targeted epigenetic therapy with novel PPI inhibitors obtained by directed chemical evolution.  相似文献   
26.
Journal of Inorganic and Organometallic Polymers and Materials - This work aimed to investigate the impact of Lead-fluoride based glasses via theoretical and simulation techniques on mechanical and...  相似文献   
27.
Different samples of xTeO2.(25-y)B2O3.zV2O5.yYb2O3 (or TBVY) new glass material were synthesized by the classical melt-quenching method. Structural, optical, physical, and thermal analyses of the synthesized glasses were performed in addition to Monte Carlo simulation to test radiation shielding properties. The results showed that increasing ratios of Yb2O3 (y = 0.0, 0.5, 1.0, and 1.5 mol%) produced monotonic density values of the synthesized glasses ranging from 4.70058 g cm?3 to 5.01038 g cm?3. XRD and FTIR analyses were used to confirm the glass structure of all samples. Optical transmittance and absorption parameters varied almost monotonically with increasing ratios of Yb2O3 indicating the ability to predict and control these properties using Yb2O3 additive. Furthermore, simulated radiation interaction parameters, such as attenuation coefficients and half-value layer, exhibited well-behaved dependence on the concentration ratio of the Yb2O3 additive. This approach to glass material synthesis demonstrate the useful synergetic effect of combining structural, optical, and radiation characteristics.  相似文献   
28.
In this experimental study, the usability of waste marble dust (WMD) as an additive material in blended cement has been investigated. For this purpose, waste marble dust added cements (WMDCs) have been obtained by intergrinding WMD with Portland cement clinker at different blend ratios: 2.5%, 5.0%, 7.5% and 10% by weight. 40 × 40 × 160 mm mortar prisms have been produced with the obtained cements. Strength tests have been carried out on mortar specimen at 7, 28, and 90 days. WMDCs have been compared to each other as well as to control cements of CEM I and CEM II with respect to their physical, chemical and mechanical properties. Obtained results showed that WMDCs conform to EN 197-1 standard and thus 10% WMD can be used as an additive material in cement manufacturing.  相似文献   
29.
Melt electrowriting (MEW) is a direct-writing technology for small diameter fibers; however, due to electrostatic attraction, the technique is restricted in how close these microfibers can be positioned on the collector. Here, the minimum interfiber distance between parallel poly(ε-caprolactone) MEW microfibers is determined for different fiber diameters and number of layers on noncoated and star-shaped poly(ethylene oxide-stat-propylene oxide) (sP(EO-stat-PO))-coated glass coverslips. The effect of the fiber diameter, the number of fiber layers, and shape of turning loops affect precision and the minimum interfiber distance. Single fibers with diameter of 5, 10, and 15 µm have a minimum interfiber distance without fiber bridging of 33 ± 2.7, 54 ± 2.2, and 62 ± 2.7 µm, respectively. Increasing the number of layers to ten increases this minimum interfiber distance approximately twofold to 60 ± 3.5, 97 ± 4.5, and 102 ± 2.7 µm for the increasing fiber diameters. The sP(EO-stat-PO) slightly increases the minimum interfiber distance for the 15 µm diameter group only, with spacing for the 5 and 10 µm fibers unaffected by the coating. Identifying and determining the fabrication limits for MEW is highly instructional for users working and designing scaffolds with this technology.  相似文献   
30.
Multimedia Tools and Applications - In this paper, four novel, simple and robust approaches, which are left to right local binary patterns (LBPLL2R), top to down local binary patterns (LBPT2D),...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号