全文获取类型
收费全文 | 338篇 |
免费 | 49篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 101篇 |
金属工艺 | 3篇 |
机械仪表 | 2篇 |
建筑科学 | 14篇 |
矿业工程 | 2篇 |
能源动力 | 6篇 |
轻工业 | 115篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 9篇 |
一般工业技术 | 50篇 |
冶金工业 | 47篇 |
自动化技术 | 29篇 |
出版年
2023年 | 5篇 |
2022年 | 19篇 |
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 12篇 |
2014年 | 22篇 |
2013年 | 32篇 |
2012年 | 22篇 |
2011年 | 25篇 |
2010年 | 13篇 |
2009年 | 16篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1976年 | 2篇 |
1943年 | 1篇 |
排序方式: 共有387条查询结果,搜索用时 187 毫秒
61.
Concentrates of triterpenic acids obtained from crude olive pomace oils: characterization and evaluation of their potential antioxidant activity
下载免费PDF全文
![点击此处可从《Journal of the science of food and agriculture》网站下载免费的PDF全文](/ch/ext_images/free.gif)
62.
Chun-Hsing Ho María Francisca Martínez González Cristina Pilar Martín Linares 《Frontiers of Structural and Civil Engineering》2017,11(1):1-7
The objective of this research is to evaluate an impact of asphalt mixture beams with varying sizes of aggregate in the Bending Beam Rheometer (BBR) for testing/predicting thermal cracking properties of asphalt pavements. The BBR test has following benefits: the equipment is cheaper, it uses smaller specimens, faster conditioning, easier availability for quality control, easier to manage, etc. However some concerns have been raised: some consider that the size of the aggregate may affect the test’s results; the other concern is that such small beams cannot represent the whole properties of the asphalt pavement. To address these criticisms, imaging techniques, statistical analysis, and viscoelastic modeling are used. Asphalt thin beams prepared with three different nominal maximum aggregate size (NMAS) (12.5mm, 9.5 mm, and 4.75 mm) were tested at three different temperatures (-18°C, -24°C, and -30°C). Based on results from statistical analyses and viscoelasticity, the ratio of asphalt binders and voids and stiffness differences among the three NMAS specimens are not significant, meaning that the impact of asphalt thin beams prepared with the three NMAS on the prediction of thermal cracking is minimal and can be neglected. 相似文献
63.
64.
A Comparative Study Between Labeling and Reality: The Case of Phytochemical Composition of Commercial Pomegranate‐Based Products
下载免费PDF全文
![点击此处可从《Journal of food science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marina Cano‐Lamadrid Leontina Lipan Ángel Calín‐Sánchez Francisca Hernández Ángel A. Carbonell‐Barrachina 《Journal of food science》2017,82(8):1820-1826
Manufacturers are deeply involved in the development of new pomegranate‐based products, which have acquired great prestige due to many studies proving their potential health benefits. Commercial pomegranate products including capsules and supplements and juices and nectars were assayed. The contents of the key phytochemical compounds (punicalagin, ellagic acid, and total polyphenolic content) and the associated antioxidant capacity (DPPH?, ABTS?+, and FRAP) were analyzed. The experimental ranges of punicalagin and ellagic acid contents were 0.96 to 308 mg/g and 0.09 to 13.1 mg/g, respectively. Punicalagin content was positively correlated (P < 0.001) with DPPH? and total polyphenolic content values. No significant (P > 0.05) correlation was observed among ellagic acid with the antioxidant capacity. The labeling standardization of these products is necessary due to the wide variability among “theoretically” similar pomegranate‐based products. 相似文献
65.
Physico‐chemical and physiological changes during fruit development and on‐tree ripening of two Spanish jujube cultivars (Ziziphus jujuba Mill.)
下载免费PDF全文
![点击此处可从《Journal of the science of food and agriculture》网站下载免费的PDF全文](/ch/ext_images/free.gif)
66.
Masao Shimizu Naoto Kudo Yoshinobu Nakajima Noboru Matsuo Yoshihisa Katsuragi Ichiro Tokimitsu Francisca Barceló 《Journal of the American Oil Chemists' Society》2008,85(7):629-633
Olive oils have a higher relative diacylglycerol (DAG) content than other plant oils. The lipase in olive fruits is involved
in DAG production and is directly related to the acidity of the olive oil. However, the lipase activity and positional selectivity
have not been clarified. To investigate the properties of olive fruit lipase, olive fruits of the Mission variety harvested
during mid-December of 2005 on Shodoshima Island (Japan) were stored at 20, 30 or 40 °C for 4 weeks. Changes in the acidity
and acylglycerol content of the oils extracted from the stored fruits were analyzed. The acidity and DAG content of the olive
oils increased due to triacylglycerol (TAG) hydrolysis during storage. sn-1,2-DAGs preferentially increased during the early stages of storage, indicating that the olive fruit lipase is enantioselective
for the sn-3 position, while non-enzymatic isomerization of sn-1,2-DAGs was observed throughout the entire duration of storage. Kinetic analysis revealed that the enantioselectivity of
olive fruit lipase for the sn-3 position was approximately four times greater than for the sn-1 position. The lipase was gradually inactivated at temperatures of 30 °C or higher, and the ratios of the rate constant
for inactivation to TAG hydrolysis at the sn-3 position was 0.2, 13, and 23 at 20, 30, and 40 °C, respectively. 相似文献
67.
Hernandez M Recio G Martin-Palma RJ Garcia-Ramos JV Domingo C Sevilla P 《Nanoscale research letters》2012,7(1):364
Fluorescence spectra of anti-tumoral drug emodin loaded on nanostructured porous silicon have been recorded. The use of colloidal nanoparticles allowed embedding of the drug without previous porous silicon functionalization and leads to the observation of an enhancement of fluorescence of the drug. Mean pore size of porous silicon matrices was 60 nm, while silver nanoparticles mean diameter was 50 nm. Atmospheric and vacuum conditions at room temperature were used to infiltrate emodin-silver nanoparticles complexes into porous silicon matrices. The drug was loaded after adsorption on metal surface, alone, and bound to bovine serum albumin. Methanol and water were used as solvents. Spectra with 1 μm spatial resolution of cross-section of porous silicon layers were recorded to observe the penetration of the drug. A maximum fluorescence enhancement factor of 24 was obtained when protein was loaded bound to albumin, and atmospheric conditions of inclusion were used. A better penetration was obtained using methanol as solvent when comparing with water. Complexes of emodin remain loaded for 30 days after preparation without an apparent degradation of the drug, although a decrease in the enhancement factor is observed. The study reported here constitutes the basis for designing a new drug delivery system with future applications in medicine and pharmacy. 相似文献
68.
Lizcano LJ Viloria-Bernal M Vicente F Berrueta LA Gallo B Martínez-Cañamero M Ruiz-Larrea MB Ruiz-Sanz JI 《International journal of molecular sciences》2012,13(5):5454-5467
Diverse plants of ethnobotanic interest in Amazonia are commonly used in traditional medicine. We determined the antioxidant potential against lipid peroxidation, the antimicrobial activity, and the polyphenol composition of several Amazonian plants (Brownea rosademonte, Piper glandulosissimum, Piper krukoffii, Piper putumayoense, Solanum grandiflorum, and Vismia baccifera). Extracts from the plant leaf, bark, and stem were prepared as aqueous infusions, as used in folk medicine, and added to rat liver microsomes exposed to iron. The polyphenolic composition was detected by reverse-phase HPLC coupled to diode-array detector and MS/MS analysis. The antimicrobial activity was tested by the spot-on-a-lawn method against several indicator microorganisms. All the extracts inhibited lipid oxidation, except the P. glandulosissimum stem. The plant extracts exhibiting high antioxidant potential (V. baccifera and B. rosademonte) contained high levels of flavanols (particularly, catechin and epicatechin). By contrast, S. grandiflorum leaf, which exhibited very low antioxidant activity, was rich in hydroxycinnamic acids. None of the extracts showed antimicrobial activity. This study demonstrates for the first time the presence of bioactive polyphenolic compounds in several Amazonian plants, and highlights the importance of flavanols as major phenolic contributors to antioxidant activity. 相似文献
69.
Mónica Rubilar Eduardo Morales Roberto Sáez Francisca Acevedo Barbara Palma Mario Villarroel Carolina Shene 《European Journal of Lipid Science and Technology》2012,114(7):760-771
The main objective of this study was to evaluate the effect of incorporating polyphenolic‐enriched fractions from murta leaves on the oxidative stability of linseed oil microencapsulated by spray drying. For this purpose, polyphenol‐enriched fractions from murta leaves were separated by gel permeation chromatography and chemically characterized. The oxidative stability of microencapsulated linseed oil (MLO) with antioxidants was evaluated in storage conditions at 25°C for 40 days. The antioxidant effects of the polyphenolic fractions and commercial antioxidants (BHT and trolox) on microencapsulated oil were evaluated by the value of conjugated dienes, peroxide, and p‐anisidine. In the initiation step of the oxidation, no significant oxidation delay (p>0.05) in MLO containing fractions F6, F8, or BHT and trolox was observed. However, in the termination step of the oxidation, the addition of fractions F6, F8, and BHT and trolox decreases significantly (p ≤ 0.05) the rancidity in MLO. Furthermore, the results of this study demonstrated the importance of the addition of natural antioxidants such as fractions of murta leaf extract in microencapsulated linseed oil to increase its resistance to oxidation. Practical applications: For incorporating linseed oil, a source of omega‐3 fatty acids, in the diet it is necessary to protect it against oxidative rancidity, the main cause of deterioration that affects food with a high unsaturated fat content. Microencapsulation is effective in retarding or suppressing the oxidation of unsaturated fatty acids and natural plants extracts are effective in inhibiting the lipid oxidation of microencapsulated oil. The use of process technology and a natural additive is expected to increase storage stability and enable its use in dry foods such as instant products. Linseed oil can be used in human nutrition as well as in animal feed as a replacement for fish oil. 相似文献
70.
Global temperature is expected to rise throughout this century, and blooms of cyanobacteria in lakes and estuaries are predicted to increase with the current level of global warming. The potential environmental, economic and sanitation repercussions of these blooms have attracted considerable attention among the world’s scientific communities, water management agencies and general public. Of particular concern is the worldwide occurrence of hepatotoxic cyanobacteria posing a serious threat to global public health. Here, we highlight plausible effects of global warming on physiological and molecular changes in these cyanobacteria and resulting effects on hepatotoxin production. We also emphasize the importance of understanding the natural biological function(s) of hepatotoxins, various mechanisms governing their synthesis, and climate-driven changes in food-web interactions, if we are to predict consequences of the current and projected levels of global warming for production and accumulation of hepatotoxins in aquatic ecosystems. 相似文献