全文获取类型
收费全文 | 160篇 |
免费 | 23篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 31篇 |
金属工艺 | 1篇 |
机械仪表 | 4篇 |
建筑科学 | 7篇 |
能源动力 | 6篇 |
轻工业 | 71篇 |
无线电 | 7篇 |
一般工业技术 | 13篇 |
冶金工业 | 17篇 |
自动化技术 | 23篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 10篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 16篇 |
2017年 | 18篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 23篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有183条查询结果,搜索用时 15 毫秒
81.
Sanpera C Valladares S Moreno R Ruiz X Jover L 《The Science of the total environment》2008,407(1):242-249
The Prestige oil spill resulted in the mortality of several seabird species on the Atlantic NW coast of Spain. Shag casualties were particularly relevant, since populations are resident in the area the whole year round and because of several features which make them highly vulnerable to environmental hazards. Ecological catastrophes give us the opportunity of collecting samples which, otherwise, would be difficult to obtain. We examine the potential of shag corpses as bioindicators of inorganic pollution and the possible factors of variability, such as biological traits (sex, age) or nutrition status. We determined trace elements (Hg, Se, Cr, Pb, Zn and Cu) and isotopic signatures (15N, 13C) in soft tissues (muscle, liver) and in primary feathers formed at different times (before and after the Prestige) in individuals of known sex and age, collected at the time of the Prestige disaster. These were compared with data from another group of shags trapped accidentally in fishing gear in 2005.Our results did not seem to be affected by sex or age on any of the analysed variables. The higher nitrogen isotopic signatures in the soft tissues of the Prestige shags may be related to the nutrition stress caused by a poorer body condition, which is also reflected in increasing levels of some metals in the liver. This isotopic enrichment was also observed in newly forming feathers when compared to the old ones. On the other hand, the lower δ15N and Hg values in shag feathers from 2005 point to a shift in feeding resources to prey of lower trophic levels. We found that feather features (being an inert tissue and having a conservative composition), if combined with careful dating and chemical analysis, offer a very useful tool to evaluate temporal and spatial changes in seabird ecology in relation to pollution events. 相似文献
82.
Fernández-Saavedra R Darder M Gómez-Avilés A Aranda P Ruiz-Hitzky E 《Journal of nanoscience and nanotechnology》2008,8(4):1741-1750
The present work introduces a comparative study on the use of polymer nanocomposites containing clay minerals of different structure, such as montmorillonite and sepiolite as host solids for the templating synthesis of carbon-like materials from different organic precursors. Carbon-clay nanocomposites were obtained by polymerization of either acrylonitrile or sucrose previously inserted in the pores of the clay minerals, followed by their further thermal transformation in carbon-like compounds. Acid treatment of the resulting carbon-clay nanocomposites removes the inorganic templates giving carbon-like materials with different textural features. Polymer-clay, carbon-clay and carbon-like materials have been characterized by applying spectroscopic techniques as FTIR and in situ EIS (electrochemical impedance spectroscopy) and other structural, textural and analytical tools (chemical analysis, XRD, SEM-EDX, TEM-EDX, N2 adsorption isotherms,...). Electrochemical properties of these carbon-clay nanocomposites, as well as their templated carbonaceous materials and their use as electrode materials of different electrochemical devices such as rechargeable Li-batteries, supercapacitors and electrochemical sensors, are also discussed. 相似文献
83.
Hyperuricemia is Associated with Increased Apo AI Fractional Catabolic Rates and Dysfunctional HDL in New Zealand Rabbits
下载免费PDF全文
![点击此处可从《Lipids》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Miriam?Martínez-Ramírez Cristóbal?Flores-Castillo L.?Gabriela?Sánchez-Lozada Rocío?Bautista-Pérez Elizabeth?Carreón-Torres José?Manuel?Fragoso José?Manuel?Rodriguez-Pérez Fernando?E.?García-Arroyo Victoria?López-Olmos María?Luna-Luna Gilberto?Vargas-Alarcón Martha?Franco Oscar?Pérez-MéndezEmail author 《Lipids》2017,52(12):999-1006
The potential cause–effect relationship between uric acid plasma concentrations and HDL functionality remains elusive. Therefore, this study aimed to explore the effect of oxonic acid (OA)-induced hyperuricemia on the HDL size distribution, lipid content of HDL subclasses, and apo AI turnover, as well as HDL functionality in New Zealand white rabbits. Experimental animals received OA 750 mg/kg/day by oral gavage during 21 days. The HDL-apo AI fractional catabolic rate (FCR) was determined by exogenous labeling with 125I, and HDL subclasses were determined by sequential ultracentrifugation and PAGE. Paraoxonase-1 activity (PON-1) and the effect of HDL on relaxation of aorta rings in vitro were determined as an indication of HDL functionality. Oxonic acid induced a sixfold increase of uricemia (0.84 ± 0.06 vs. 5.24 ± 0.12 mg/dL, P < 0.001), and significant decreases of triglycerides and phospholipids of HDL subclasses, whereas HDL size distribution and HDL-cholesterol remained unchanged. In addition, HDL-apo AI FCR was significantly higher in hyperuricemic rabbits than in the control group (0.03697 ± 0.0038 vs. 0.02605 ± 0.0017 h?1 respectively, P < 0.05). Such structural and metabolic changes were associated with lower levels of PON-1 activities and deleterious effects of HDL particles on endothelium-mediated vasodilation. In conclusion, hyperuricemia is associated with structural and metabolic modifications of HDL that result in impaired functionality of these lipoproteins. Our data strongly suggest that uric acid per se exerts deleterious effects on HDL that contribute to increase the risk of atherosclerosis. 相似文献
84.
Ainara Jimenez Andoni Beriain Juan Francisco Sevillano Ivan Rebollo Roc Berenguer 《Analog Integrated Circuits and Signal Processing》2017,91(3):433-444
This work presents a nonius time to digital converter (TDC) adapted to a passive RF identification (RFID) pressure sensor tag. The proposed converter exploits the characteristics of time-based sensor interfaces and allows reducing voltage supply and power consumption while maintaining resolution and conversion efficiency. The nonius TDC has been designed and fabricated using the TSMC 90 nm standard CMOS technology. The main blocks of the converter are described and both the resolution adjustment and measurement processes are explained in detail. Measurement results show 10.49 bits of effective resolution for an input time range from 28.19 to 42.93 μs. With a sampling rate of 19 KS/s the converter has a conversion efficiency of 0.395 pJ/bit with a voltage supply of only 0.6 V. This characteristics in the proposed nonius TDC enables an increased reading range of the passive RFID pressure sensor tag. 相似文献
85.
Calvo Rocío Iglesias Ana Castaño Leonardo 《Universal Access in the Information Society》2017,16(3):593-607
Universal Access in the Information Society - Chat applications are being used for more than one decade in learning environments as a useful computer-supported collaborative learning tool. However,... 相似文献
86.
Daytime running lamps (DRL) on vehicles have proven to be an effective measure to prevent accidents during the daytime, particularly when pedestrians and cyclists are involved. However, there are negative interactions of DRL with other functions in automotive lighting, such as delays in pedestrians’ visual reaction time (VRT) when turn indicators are activated in the presence of DRL. These negative interactions need to be reduced. This work analyses the influence of variables inherent to pedestrians, such as height, gender and visual defects, on the VRT using a classification and regression tree as an exploratory analysis and a generalized linear model to validate the results. Some pedestrian characteristics, such as gender, alone or combined with the DRL colour, and visual defects, were found to have a statistically significant influence on VRT and, hence, on traffic safety. These results and conclusions concerning the interaction between pedestrians and vehicles are presented and discussed.
Practitioner Summary: Visual interactions of vehicle daytime running lamps (DRL) with other functions in automotive lighting, such as turn indicators, have an important impact on a vehicle’s conspicuity for pedestrians. Depending on several factors inherent to pedestrians, the visual reaction time (VRT) can be remarkably delayed, which has implications in traffic safety. 相似文献
87.
Sara Jaramillo‐Carmona Rocío Rodriguez‐Arcos Ana Jiménez‐Araujo Sergio López Juan Gil Roberto Moreno Rafael Guillén‐Bejarano 《Journal of food science》2017,82(3):638-646
The aim of this work was to study the saponin profiles from spears of different wild asparagus species in the context of its genetic diversity aside from geographical seed origin. They included Asparagus pseudoscaber Grecescu, Asparagus maritimus (L.) Mill., Asparagus brachiphyllus Turcz., Asparagus prostrates Dumort., and Asparagus officinalis L. The saponin analysis by LC‐MS has shown that saponin profile from wild asparagus is similar to that previously described for triguero asparagus from Huétor‐Tájar landrace (triguero HT), which had not ever been reported in the edible part of asparagus. All the samples, except A. officinalis, were characterized for having saponins distinct to protodioscin and the total saponin contents were 10‐fold higher than those described for commercial hybrids of green asparagus. In particular, A. maritimus from different origins were rich in saponins previously found in triguero HT. These findings supported previous suggestion, based on genetic analysis, about A. maritimus being the origin of triguero HT. Multivariate statistics including principal component analysis and hierarchical clustering analysis were used to define both similarities and differences among samples. The results showed that the greatest variance of the tested wild asparagus could be attributed to differences in the concentration of particular saponins and this knowledge could be a tool for identifying similar species. 相似文献
88.
Rocío Gil‐Muñoz José I. Fernández‐Fernández Rosario Vila‐López Adrián Martinez‐Cutillas 《International Journal of Food Science & Technology》2010,45(9):1870-1877
The aim of our research has been to investigate the pattern of accumulation of anthocyanins in the skin of Monastrell variety and to establish if the fingerprint of this cultivar changed in six different areas from Denomination of Origen Jumilla during ripening stage in two consecutive seasons (2007 and 2008). The results show that the anthocyanin profile for Monastrell variety is maintained: it could be observed a higher proportion of non‐acylated anthocyanins, a higher proportion of coumarylated than acetyl derivatives and a higher proportion of trihydroxylated than dihydroxylated anthocyanins. During ripening period, in all zones studied, we observed the same trends: increasing of cyanidin, peonidin and malvidin‐3‐glucoside and decreasing of the other two monoglucosides (delphinidin and petunidin). Slightly quantitative differences were observed for the different zones in the 2 years studied, leading to the conclusion that edaphoclimatic factors also influence the accumulation of anthocyanin compounds. 相似文献
89.
Plant Glandular Trichomes as Targets for Breeding or Engineering of Resistance to Herbivores 总被引:2,自引:0,他引:2
Joris J. Glas Bernardus C. J. Schimmel Juan M. Alba Rocío Escobar-Bravo Robert C. Schuurink Merijn R. Kant 《International journal of molecular sciences》2012,13(12):17077-17103
Glandular trichomes are specialized hairs found on the surface of about 30% of all vascular plants and are responsible for a significant portion of a plant’s secondary chemistry. Glandular trichomes are an important source of essential oils, i.e., natural fragrances or products that can be used by the pharmaceutical industry, although many of these substances have evolved to provide the plant with protection against herbivores and pathogens. The storage compartment of glandular trichomes usually is located on the tip of the hair and is part of the glandular cell, or cells, which are metabolically active. Trichomes and their exudates can be harvested relatively easily, and this has permitted a detailed study of their metabolites, as well as the genes and proteins responsible for them. This knowledge now assists classical breeding programs, as well as targeted genetic engineering, aimed to optimize trichome density and physiology to facilitate customization of essential oil production or to tune biocide activity to enhance crop protection. We will provide an overview of the metabolic diversity found within plant glandular trichomes, with the emphasis on those of the Solanaceae, and of the tools available to manipulate their activities for enhancing the plant’s resistance to pests. 相似文献
90.
Roc��o Carvajal Alcaide 《Nexus Network Journal》2011,13(3):631-648
Historic treatises on stonecutting of the sixteenth and seventeenth centuries contributed to progress in the study and understanding of properties of the different surfaces and the intersections between them. One of the topics that contributed most towards the development of knowledge of the geometry of surfaces was the practical use of ruled surfaces. Defining the geometry of a piece of stone by surfaces that can be cut using a ruler as a guide and a check has always been considered very interesting in the field of stonecutting. This present study focuses on stairs in two Spanish treatises to illustrate how warped surfaces were treated. 相似文献