全文获取类型
收费全文 | 176篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 61篇 |
金属工艺 | 3篇 |
机械仪表 | 6篇 |
建筑科学 | 3篇 |
能源动力 | 6篇 |
轻工业 | 23篇 |
水利工程 | 3篇 |
无线电 | 13篇 |
一般工业技术 | 35篇 |
冶金工业 | 14篇 |
自动化技术 | 15篇 |
出版年
2023年 | 1篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 12篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 22篇 |
2012年 | 8篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 2篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 12 毫秒
91.
Hussain Iqbal Parveen Abida Rasheed Rizwan Ashraf Muhammad Arslan Ibrahim Muhammad Riaz Saima Afzaal Zarbhakhat Iqbal Muhammad 《SILICON》2019,11(6):2753-2762
Silicon - The exogenous application of silicon (Si) is reported to enhance tolerance of plants against various environmental stresses. Therefore, the present study was carried out to examine the... 相似文献
92.
Parveen Kumar Sangeeta SinghJ.K. Juneja Chandra Prakash K.K. Raina 《Ceramics International》2011,37(5):1697-1700
Ba0.80−xCaxPb0.20Ti0.90Zr0.10O3 ceramics (x = 0, 0.10 and 0.20) were synthesized by solid state reaction. Samples microstructure and dielectric, ferroelectric and piezoelectric properties were studied. Dielectric constant (?), coercive field (Ec), remanent polarization (Pr) and ratio of remanent to spontaneous polarization (Pr/Ps) were studied at different temperatures. Sample with x = 0.10 was found to have maximum and comparatively more stable Pr/Ps ratio over a wide temperature range. Dielectric loss was found to improve with increase in x whereas piezoelectric charge coefficient d33 was found to decrease with increase in x. 相似文献
93.
Parveen Saini Veena Choudhary B.P. Singh R.B. Mathur S.K. Dhawan 《Synthetic Metals》2011,161(15-16):1522-1526
Blends of polystyrene with polyaniline (PANI) coated multiwalled carbon nanotubes (MWCNTs) were designed which inherit dielectric and magnetic attributes from PANI and MWCNT respectively. The high resolution transmission electron microscopy image shows the PANI coating over MWCNT containing entrapped Fe catalyst. These blends show absorption dominated total shielding effectiveness (SET) of ?45.7 dB (>99.99% attenuation) in the 12.4–18.0 GHz range, suggesting their utility for making efficient microwave absorbers. The enhanced SET was ascribed to optimization of conductivity, skin-depth, complex permittivity and permeability. A good agreement between theoretical and experimental shielding measurements was also observed. 相似文献
94.
Joost L. D. Nelis Utpal Bose James A. Broadbent Joanne Hughes Anita Sikes Alisha Anderson Karine Caron Sabine Schmoelzl Michelle L. Colgrave 《Comprehensive Reviews in Food Science and Food Safety》2022,21(3):2391-2432
Meat quality can be affected by stress, exhaustion, feed composition, and other physical and environmental conditions. These stressors can alter the pH in postmortem muscle, leading to high pH and low-quality dark cutting (DC) beef, resulting in considerable economic loss. Moreover, the dark cutting prediction may equally provide a measure for animal welfare since it is directly related to animal stress. There are two needs to advance on-site detection of dark cutters: (1) a clear indication that biomarker (signature compounds) levels in cattle correlate with stress and DC outcome; and (2) measuring these biomarkers rapidly and accurately on-farm or the abattoir, depending on the objectives. This critical review assesses which small molecules and proteins have been identified as potential biomarkers of stress and dark cutting in cattle. We discuss the potential of promising small molecule biomarkers, including catecholamine/cortisol metabolites, lactate, succinate, inosine, glucose, and β-hydroxybutyrate, and we identify a clear research gap for proteomic biomarker discovery in live cattle. We also explore the potential of chemical-sensing and biosensing technologies, including direct electrochemical detection improved through nanotechnology (e.g., carbon and gold nanostructures), surface-enhanced Raman spectroscopy in combination with chemometrics, and commercial hand-held devices for small molecule detection. No current strategy exists to rapidly detect predictive meat quality biomarkers due to the need to further validate biomarkers and the fact that different biosensor types are needed to optimally detect different molecules. Nonetheless, several biomarker/biosensor combinations reported herein show excellent potential to enable the measurement of DC potential in live cattle. 相似文献
95.
We designed two types of very low cost solar water heaters which do not need a water supply connection. The first one consisted of two plastic bowls, one inside the other with 5 cm thickness of insulation in between. A transparent plastic cover was tied around the smaller vessel. It was found that water placed inside the smaller vessel had its temperature raised by 18°C from the ambient temperature within four hours when the average insolation was about 600 kWh/m2. The second one consisted of two earthen vessels in place of plastic bowls. The water temperature rise was 20°C under the same radiation. If either of the heaters was covered with cotton-wool insulation in the afternoon, the temperature remains 13°C above the ambient early next morning. The cost of the material was around US$ 4.50 for the plastic bowl heater while this is around US$ 3.50 for the earthen vessel water heater. 相似文献
96.
97.
Estuarine waters receive fecal pollution from a variety of sources, including humans and wildlife. Escherichia coli is one of several fecal coliform bacteria that inhabit the intestines of many warm-blooded animals that sometimes contaminate water. Its presence does not specifically implicate human fecal input, therefore it is necessary to differentiate contamination sources to accurately assess health risks. E. coli were isolated from human sources (HS) and nonhuman sources (NHS) in the Apalachicola National Estuarine Research Reserve and analyzed for fatty acid methyl ester (FAME), O-serogroup, and pulsed-field gel electrophoresis (PFGE) profiles. For FAME and PFGE analyses, there was no relationship between profile and isolate source. Human source PFGE profiles were less diverse than NHS isolates, and conversely for FAME. In contrast, O-serogrouping showed less diversity for HS vs. NHS isolates, and the predominant HS O-serogroups differed significantly (P < 0.01) from those of NHS isolates. 相似文献
98.
P. Thirukumaran A. Shakila Parveen K. Kumudha M. Sarojadevi 《Polymer Composites》2016,37(6):1821-1829
Renewable natural resources such as eugenol, furfurylamine, stearylamine, and jute fiber were used to prepare polybenzoxazine composites. The purity of eugenol which is extracted from clove was confirmed by gas chromatography. FTIR, 1H, and 13C NMR spectroscopic analysis were used to determine the structure of eugenol and the benzoxazine monomers namely 6‐allyl‐3‐furfuryl‐8‐methoxy‐3,4‐dihydro‐2H‐1,3‐benzoxazine (EF‐Bz) and 6‐allyl‐3‐octadecyl‐8‐methoxy‐3,4 dihydro‐2H‐1,3‐benzoxazine (ES‐Bz) synthesized from it. The curing analysis from differential scanning calorimetric analysis shows that the onset of curing is shifted to lower temperature (161°C) for EF‐Bz, when compared with ES‐Bz (174°C). The thermal stability analyzed from thermogravimetric analysis shows that the polybenzoxazine EF‐Pbz has higher thermal stability (T5% = 361°C) with that of ES‐Pbz (T5% = 313°C). The storage modulus, tensile, and flexural strength of the EF‐Bz/Jute fiber composite show high value when compared with ES‐Bz/Jute fiber composites. POLYM. COMPOS., 37:1821–1829, 2016. © 2014 Society of Plastics Engineers 相似文献
99.
Aniline has been polymerized in the presence of a novel dopant sodio‐5‐sulfo‐isophthallic acid (NaSIPA), via the chemical oxidative polymerization route. The thermal stability and processability of polyaniline prepared by indirect method (PD1) have been improved significantly (290°C) as compared to polyaniline doped with conventional inorganic dopants like HCl or H2SO4, without much loss of electronic conductivity (5.07 S/cm in PD1). This suggests its use for melt blending with engineering thermoplastics. However, polyaniline prepared by direct method (PD2) can be melt‐blended only with conventional thermoplastics like polyethylene, polypropylene, polystyrene, etc. Low‐temperature studies reveal the 1‐D variable range hopping as a conduction mechanism for direct polymer (PD2), with parameters To and σo as 4112 K and 15.1 S/cm, respectively. However, for indirectly doped polymer (PD1) Arrhenius‐type model, having parameters |(EF ? EC)| and σC as 0.04 eV and 28.4 S/cm, respectively, it suited well. The coherence length as found from XRD data was around 28.8 nm for PD1 and 25.2 nm for PD2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
100.
Synthesis and characterizations of nano-sized Ni(OH)2 and Ni(OH)2/poly(vinyl alcohol) nano composite
M. Fathima Parveen S. Umapathy V. Dhanalakshmi R. Anbarasan 《Journal of Materials Science》2009,44(21):5852-5860
Nano-sized Ni(OH)2 was synthesized by a co-precipitation method. Peaks between 500 and 750 cm−1 in Fourier transform infrared spectroscopy (FTIR) confirmed the presence of metal hydroxide stretching. Thermo gravimetric
analysis inferred that 69 wt% residue remained above 750 °C. High-resolution transmission electron microscopy analysis of
Ni(OH)2 revealed its size ranged from 80 to 110 nm with smooth morphology. Scanning electron microscopy inferred that pure Ni(OH)2 has nano rod-like morphology and higher weight percentage of aniline-intercalated Ni(OH)2 has agglomerated structure. UV–Vis spectrum detected the presence of Ni2+ ions at 210 nm and the existence of amino group in the basal spacing of Ni(OH)2 was not clearly appeared in the spectrum. Photoluminescence (PL) inferred that aniline-intercalated Ni(OH)2 showed higher PL intensity than the pristine poly(vinyl alcohol) its and nano composite. 相似文献