全文获取类型
收费全文 | 516篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 63篇 |
金属工艺 | 17篇 |
机械仪表 | 22篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 81篇 |
轻工业 | 48篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 35篇 |
一般工业技术 | 62篇 |
冶金工业 | 11篇 |
原子能技术 | 3篇 |
自动化技术 | 155篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 16篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 53篇 |
2012年 | 31篇 |
2011年 | 41篇 |
2010年 | 29篇 |
2009年 | 46篇 |
2008年 | 38篇 |
2007年 | 32篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1943年 | 2篇 |
排序方式: 共有529条查询结果,搜索用时 0 毫秒
21.
Ring Opening of Epoxidized Soybean Oil with Compounds Containing Two Different Functional Groups
下载免费PDF全文
![点击此处可从《Journal of the American Oil Chemists](/ch/ext_images/free.gif)
Kemal Karadeniz Hatice Akı Mustafa Yasin Sen Yakup Çalıkoğlu 《Journal of the American Oil Chemists' Society》2015,92(5):725-731
Epoxidized vegetable oils are desirable chemicals due to their eco‐friendly characteristics and their being a major source of many green products. Ring opening is one of the ways to convert these epoxidized oils to some new intermediates. The use of mono‐functional amines, alcohols, acid anhydrides and thioethers for epoxy ring opening has been reported in the literature. In this study, thioglycolic acid (TGA) bearing thiol and carboxylic acid as two different functional groups and methyl ester of thioglycolic acid (TGAME) were used. Currently, there is no reported literature describing epoxy ring opening using chemicals bearing two different functional groups simultaneously. In this way, two new polyols were synthesized, one with TGA (polyol 1) and one with TGAME (polyol 2). FTIR and 1H‐ and 13C‐NMR spectroscopy confirmed that the ring was opened by the carboxylic acid group of TGA, and the thiol group was not involved in the ring opening whereas the ring was opened by the thiol group in the case of TGAME. 相似文献
22.
Brajendra Kumar Singh Jeremy Coulter Mohammad Abdul Ghani Sayani Syed M. Sami Mohammad Khalid Kemal E. Tepe 《The International journal of environmental studies》2013,70(5):765-776
Communication systems are needed to integrate generated power from wind farms with the electrical grid. This paper provides a comprehensive review of available communication technologies, protocols and objectives related to wind energy and electrical grid integration. This paper summarizes the communication system solutions for wind generation. A major obstacle is an absence of unified communication architectures and standards. 相似文献
23.
Fatma Tosun Çiğdem Akyüz Kızılay Kevser Erol Fatma Sultan Kılıç Mine Kürkçüoğlu Kemal Hüsnü Can Başer 《Food chemistry》2008
The anticonvulsant activity of furanocoumarins, coumarin mixture and the essential oil obtained from the fruits of Heracleum crenatifolium was examined against maximal electroshock (MES)-induced seizures in mice. Bergapten showed significant anticonvulsant activity. The furanocoumarins isolated from the fruits of the plant were identified using thin-layer chromatography, melting points and spectroscopic methods (IR, MS, 1H NMR) as isobergapten (1), pimpinellin (2), bergapten (3), isopimpinellin (4), sphondin (5) and byak-angelicol (6). The essential oil content of the fruits were found as 5.5%. Twenty-two compounds representing 99.3% of the essential oil obtained from the fruits of H. crenatifolium were determined and the major components were identified as octanol and octyl acetate (3.1% and 88.4% respectively) by GC and GC–MS. 相似文献
24.
Ergin Murat Altuner Hami Alpas Yasar Kemal Erdem Faruk Bozoglu 《European Food Research and Technology》2006,222(3-4):392-396
Interest in high hydrostatic pressure (HHP) applications on milk and dairy products has recently increased as HHP offers a
new technology for food preservation to the food industry. Although HHP-induced microbial destruction, rennet or acid coagulation
of milk and increase in cheese yield has been reported, the actual effect of HHP application on milk constituents still remains
to be unexplained. Therefore, we have analyzed the effect of HHP on physicochemical and biochemical properties such as turbidity,
pH and especially protein micelle surface hydrophobicity of milk proteins. To serve for this purpose, milk samples with different
fat contents were pressurized from 110 to 440 MPa at 25 °C for 10 and 20 min. Turbidity decreased with pressure increase and
there was a slight change in pH. In order to measure the extent of exposure of hydrophobic groups of proteins to HHP, the
method described by Bonomi et al. [1], based on use of a fluorescent probe, was utilized. In the light of the results obtained, it can be concluded that HHP has
an effect on non-covalent interactions and especially hydrophobic bonds in milk. As the pressure is increased from 110 to
440 MPa, the micelles possibly decompose into sub-micelles and the embedded hydrophobic areas inside these micelles re-position
in such a way that they can readily interfere with the fluorescent marker, ANS. These results may lead to practical applications
of HHP treatment in the dairy industry to produce microbiologically safe, minimally processed products with high nutritional
and sensory quality and novel texture. 相似文献
25.
26.
Kemal Kocabaş Özlem Bilgili Nuray Yaşar 《Journal of Superconductivity and Novel Magnetism》2009,22(7):643-650
In this study, the effects of sintering temperature on the Bi-2223 phase formation and the influence of minor phases on the
intergranular properties of Sb substituted Bi-2223 samples were investigated. The samples were prepared by solid-state reaction
method with different sintering temperatures ranging from 800 to 855 °C. The samples were characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM) and density measurements. We observed the optimal temperature of the Sb + Pb substituted
Bi-2223 system as 845 °C. 相似文献
27.
Ercan Varol Selahattin Akcay Banu Kale Koroglu 《The Science of the total environment》2010,408(11):2295-2298
Sixty three patients with endemic fluorosis (36 males/27 females; mean age 33.9 ± 8.6 years) and 45 age, sex and body mass index (BMI) matched healthy controls (30 males/15 females; mean age 32.7 ± 8.8 years) were included in this study. Basic echocardiographic measurements, left ventricular diastolic parameters and left ventricular myocardial performance index (MPI) were measured. The left ventricular MPI was calculated as (isovolumic contraction time + isovolumic relaxation time) / aortic ejection time by Doppler. The urine fluoride levels of fluorosis patients were significantly higher than control subjects as expected (1.9 ± 0.1 mg/l vs 0.4 ± 0.1 mg/l respectively; P < 0.001). Isovolumic relaxation time (IVRT) and deceleration time (DT) were significantly higher in fluorosis patients than in controls (for IVRT 106.9 ± 15.6 ms vs 96.7 ± 12.2 ms; P < 0.001 and for DT 211.7 ± 30.7 ms vs 188.0 ± 30.0 ms; P < 0.001, respectively). MPI was significantly higher in fluorosis patients than in controls (0.62 ± 0.15 ms vs 0.49 ± 0.10 ms; P < 0.001, respectively). We have shown that chronic fluorosis patients had left ventricular diastolic and global dysfunctions. 相似文献
28.
Yasin Varol Hakan F. Oztop Ahmet Koca Engin Avci 《Expert systems with applications》2009,36(3):5813-5821
Forecasting of entropy generation of laminar natural convection in a partially cooled square cross-sectional room has been performed using support vector machines (SVM). The two-dimensional room was modeled as floor heating story with a window. Values of temperature and velocities were obtained by solving governing equations of natural convection with finite difference technique and using these values entropy generation was calculated with its definition. Forecasting of entropy generation due to fluid friction irreversibility (FFI) and heat transfer irreversibility (HTI) were made with known values for unknown parameters using SVM. Thus, calculation time was extremely reduced and values were obtained even for non-convergence cases. It was observed that the SVM was a strong method to predict the entropy generation without computational fluid dynamic analysis for all cases. 相似文献
29.
Robust microencapsulated phase change materials in concrete mixes for sustainable buildings
下载免费PDF全文
![点击此处可从《国际能源研究杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Beyza Beyhan Kemal Cellat Yeliz Konuklu Caner Gungor Okan Karahan Cengiz Dundar Halime Paksoy 《国际能源研究杂志》2017,41(1):113-126
For passive building applications, phase change materials (PCMs) are microencapsulated to avoid leakage of PCM from concrete structure. The primary challenge of using microencapsulated PCM (MPCM) is its weak shell structure. New MPCMs with different shell compositions to prevent breakage during mixing in fresh concrete are needed. In this study, free radical polymerization method to microencapsulate capric acid–myristic acid mixture as PCM with two different methyl methacrylate co‐polymers is proposed to produce robust MPCMs for building applications. Two new microcapsules (MPCM‐1 and MPCM‐2) having latent heats of 91.9 and 97.3 J/g were synthesized. SEM analyses showed the size of microcapsules being in the range of 400–850 nm for MPCM‐1 and 250–475 nm for MPCM‐2. Analyses also reveal that the shells of MPCMs were not harmed, as they were added into concrete mixes. The microsphere's geometry was preserved, and distribution was homogeneous. The MPCMs were also studied under thermal tests of 1000 heating/cooling cycles. No significant changes in thermal properties were observed after thermal cycling tests. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
30.
Super-resolution applications require sub-pixel registrations of low resolution images to be almost exact due to the deterioration caused by inaccurate image registration. A linear-least-squares technique is proposed to refine sub-pixel translation parameters, which can be employed when the images are registered but just where there is not enough sub-pixel accuracy. In the technique, it is assumed that low resolution pixels are obtained by area sampling high resolution pixel field which have twice the density of their low resolution correspondents. Using this downsampling schema, a set of equations is formed. Assumed geometry and layout provide a constraint set to be used with the equation set. The sub-pixel translations are then found using least-squares-solution-with-equality-constraints. The method is shown to improve the registration accuracy. 相似文献