全文获取类型
收费全文 | 922篇 |
免费 | 38篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 269篇 |
金属工艺 | 6篇 |
机械仪表 | 10篇 |
建筑科学 | 72篇 |
矿业工程 | 2篇 |
能源动力 | 20篇 |
轻工业 | 164篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 33篇 |
一般工业技术 | 86篇 |
冶金工业 | 210篇 |
原子能技术 | 1篇 |
自动化技术 | 81篇 |
出版年
2023年 | 10篇 |
2022年 | 15篇 |
2021年 | 28篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 24篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 54篇 |
2012年 | 45篇 |
2011年 | 41篇 |
2010年 | 43篇 |
2009年 | 36篇 |
2008年 | 43篇 |
2007年 | 44篇 |
2006年 | 43篇 |
2005年 | 33篇 |
2004年 | 37篇 |
2003年 | 20篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 18篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1974年 | 5篇 |
1966年 | 12篇 |
1965年 | 13篇 |
1964年 | 9篇 |
1963年 | 13篇 |
1962年 | 9篇 |
1961年 | 12篇 |
1960年 | 11篇 |
排序方式: 共有960条查询结果,搜索用时 656 毫秒
61.
Waseem Hiwar Marco-Felipe King Farag Shuweihdi Louise A. Fletcher Stephanie J. Dancer Catherine J. Noakes 《Indoor air》2021,31(5):1308-1322
Airborne microorganisms in hospitals have been associated with several hospital-acquired infections (HAIs), and various measures of indoor air quality (IAQ) parameters such as temperature, relative humidity, carbon dioxide (CO2), particle mass concentration, and particle size have been linked to pathogen survival or mitigation of pathogen spread. To investigate whether there are quantitative relationships between the concentration of airborne microorganisms and the IAQ in the hospital environment. Web of Science, Scopus and PubMed databases were searched for studies reporting airborne microbial levels and any IAQ parameter(s) in hospital environments, from database inception to October 2020. Pooled effect estimates were determined via random-effects models. Seventeen of 654 studies were eligible for the meta-analysis. The concentration of airborne microbial measured as aerobic colony count (ACC) was significantly correlated with temperature (r = 0.25 [95% CI = 0.06–0.42], p = 0.01), CO2 concentration (r = 0.53 [95% CI = 0.40–0.64], p ˂ 0.001), particle mass concentration (≤5 µg/m3; r = 0.40 [95% CI = 0.04–0.66], p = 0.03), and particle size (≤5 and ˃5 µm), (r = 0.51 [95% CI = 0.12–0.77], p = 0.01 and r = 0.55 [95% CI = 0.20–0.78], p = 0.003), respectively, while not being significantly correlated with relative humidity or particulate matter of size >5 µm. Conversely, airborne total fungi (TF) were not significantly correlated with temperature, relative humidity, or CO2 level. However, there was a significant weak correlation between ACC and TF (r = 0.31 [95% CI = 0.07–0.52], p = 0.013). Although significant correlations exist between ACC and IAQ parameters, the relationship is not definitive; the IAQ parameters may affect the microorganisms but are not responsible for the presence of airborne microorganisms. Environmental parameters could be related to the generating source, survival, dispersion, and deposition rate of microorganisms. Future studies should record IAQ parameters and factors such as healthcare worker presence and the activities carried out such as cleaning, sanitizing, and disinfection protocols. Foot traffic would influence both the generation of microorganisms and their deposition rate onto surfaces in the hospital environment. These data would inform models to improve the understanding of the likely concentration of airborne microorganisms and provide an alternative approach for real-time monitoring of the healthcare environment. 相似文献
62.
Louise L. Sousa 《Fuel Processing Technology》2010,91(2):194-196
This paper evaluates the production of methyl esters from castor oil and methanol after neutralization of castor oil with glycerol. The reaction was carried out under atmospheric pressure and ambient temperature in a batch reactor, employing potassium hydroxide as catalyst. Results showed high yield of castor oil into methyl esters after neutralization of castor oil with glycerol. The highest yield observed was of 92.5% after 15 min of reaction. The best operating condition was obtained applying an alcohol to oil molar ratio of 6.0 and 0.5% w/w of catalyst. 相似文献
63.
A comprehensive model based on a new approach was developed to simulate the duckweed growth under controlled conditions. Contrary to other approaches which use the specific growth rate, this approach uses the intrinsic growth rate which permits to differentiate the effect of duckweed mat density from that of temperature, photoperiod and phosphorus-nitrogen concentrations. The model was calibrated using data from laboratory experiments carried out during the present study and validated using other data from two literature sources. In both cases, the results demonstrated that the model was capable of predicting duckweed growth with a reliability of 95%. 相似文献
64.
Gabriel de Souza Ferreira Louise Sobral Daniel Weingart Barreto Verônica Calado 《European Journal of Lipid Science and Technology》2023,125(6):2200141
The processing of the orange leads to a large generation of waste, which is underutilized or discarded. Thus, this study proposes a route to treat oily waste from the orange juice industry, transforming it into a by-product of higher added value to the chemical industry. The orange wax is obtained by hydrodistillation and solvent extraction, and the clarification of the wax is carried out with the oxidative treatment using H2O2. A 32 Experimental Design confirmed that the factors, temperature, and concentration of the reactant, influence both response variables, the colorimetric changes and yield. The obtained waxes are characterized by chromatographic (CG-MS), thermal, and rheological analysis. The results of the CG-MS indicate that the clarification method is effective as the components responsible for the pigmentation and odor of the wax cannot be identified after the clarification process. Thermogravimetry analysis and differential exploratory calorimetryindicate a slight increase in thermal stability and a decrease in crystallinity after the clarification process. Rheological analyses show that the obtained waxes present similar flow behavior as commercial beeswax. Therefore, it can be affirmed that this work obtains a green wax from a residue for potential replacement of commercial waxes according to its properties analyzed. Practical applications: This work shows the extraction of orange wax from oily industrial wastes for possible applications in the food and cosmetics industries. The orange wax can be a sustainable substitute for nonrenewable products and supply the wax market due to the high demand. In addition, methods for processing and characterization of the waxes are presented in this work. 相似文献
65.
Louise Slade 《Critical reviews in food science and nutrition》2018,58(6):972-992
This article reviews the application of the “Food Polymer Science” approach to the practice of industrial R&D, leading to patent estates based on fundamental starch science and technology. The areas of patents and patented technologies reviewed here include: (a) soft-from-the-freezer ice creams and freezer-storage-stable frozen bread dough products, based on “cryostabilization technology” of frozen foods, utilizing commercial starch hydrolysis products (SHPs); (b) glassy-matrix encapsulation technology for flavors and other volatiles, based on structure-function relationships for commercial SHPs; (c) production of stabilized whole-grain wheat flours for biscuit products, based on the application of “solvent retention capacity” technology to develop flours with reduced damaged starch; (d) production of improved-quality, low-moisture cookies and crackers, based on pentosanase enzyme technology; (e) production of “baked-not-fried,” chip-like, starch-based snack products, based on the use of commercial modified-starch ingredients with selected functionality; (f) accelerated staling of a starch-based food product from baked bread crumb, based on the kinetics of starch retrogradation, treated as a crystallization process for a partially crystalline glassy polymer system; and (g) a process for producing an enzyme-resistant starch, for use as a reduced-calorie flour replacer in a wide range of grain-based food products, including cookies, extruded expanded snacks, and breakfast cereals. 相似文献
66.
67.
68.
69.
Glen S. Patten Mahinda Y. Abeywardena Richard J. Head Louise E. Bennett 《Journal of Functional Foods》2012,4(4):851-863
While the consumption of fruit and vegetables is protective against cardiovascular disease, the relative efficacy of specific plants is poorly substantiated. In addition, although most plants are consumed in a ‘processed’ state (i.e., including cooking), the bioactivity of processed forms of plants is also generally unknown. Effects on elements of the renin-angiotensin system (RAS) were studied in a selection of 131 dietary plant species, fungi or varietals, across 44 families, after standardised processing. Products were tested for in vitro inhibition of angiotensin converting enzyme (ACE) and of angiotensin II (AngII) binding to its receptor (AT1R). The results indicated that ACE inhibition activity was weakly correlated with AngII to AT1R inhibition and that ACE inhibitory activity was positively correlated with total polyphenolic content. These results highlight that processed forms of dietary plants exhibit broad capacity for in vitro modulation of RAS. Furthermore, considering the extensive ACE inhibitory activity reported for peptides derived from many dietary proteins, this implicates broad potential for RAS regulation by several dietary factors. With RAS elements also known to function in the gastro-intestinal (GI) tract, there is a need to understand the physiological role of dietary factors on GI function, blood pressure regulation and salt excretion. 相似文献
70.
不管有没有机会亲自去到法兰西一品当地“正宗”的鹅肝、松露、鱼子酱,浅酌一杯香槟以及葡萄酒,那些赞美诗般的菜名,洁白如雪的餐巾,以及万般星辰拱璧月的法式摆盘,总会在人脑中勾勒出一幅巴洛克风贵妇宫娥在烛火摇曳中就餐的图景。数个世纪以来,这些先入为主的印象,让法餐成了高雅、情调的代名词。浪漫的法国人为爱而痴,优雅的法国人因吃言爱。 相似文献