首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   101篇
  免费   5篇
化学工业   17篇
机械仪表   1篇
建筑科学   13篇
轻工业   34篇
水利工程   2篇
石油天然气   2篇
无线电   1篇
一般工业技术   15篇
冶金工业   4篇
原子能技术   1篇
自动化技术   16篇
  2022年   2篇
  2021年   7篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   6篇
  2013年   8篇
  2012年   4篇
  2011年   15篇
  2010年   12篇
  2009年   10篇
  2008年   8篇
  2007年   5篇
  2006年   2篇
  2004年   3篇
  2003年   6篇
  2002年   2篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
排序方式: 共有106条查询结果,搜索用时 203 毫秒
51.
Scientific production in psychology: a gender analysis   总被引:1,自引:0,他引:1  
This study aims to identify possible gender inequalities in the scholarly output of researchers in the field of psychology in Spain. A sample of 522 papers and reviews published in 2007 was extracted from the Thomson ISI Web of Science. The presence of women, the collaboration pattern and the impact of these scientific publications were analyzed. The results show that the average number of female researchers per paper was 0.42 (SD 0.33) and that 42.3 % of the papers had a female researcher as the first author. Moreover, the proportion of female authors of a paper was statistically significantly higher when the first author was female. Studies carried out in cooperation with other Spanish or international institutions had fewer female authors than studies conducted at a single center. The impact of the papers, measured by the journal impact factor and the number of citations, was independent of the authors’ gender or the proportion of female authors. In summary, the study highlights a gender imbalance in Spanish scientific output in Psychology, and a higher proportion of male researchers in international networks.  相似文献   
52.
Meta-analysis refers to the statistical methods used in research synthesis for combining and integrating results from individual studies. The present study draws on the strengths of bibliometric methods in order to offer an overview of meta-analytic research activity in psychology, as well as to characterize its most important aspects and their evolution over time. A total of 2,874 articles published in scientific journals were identified and standard bibliometric indicators (e.g., number of articles, productivity by country, and national and international collaborations) and laws (e.g., Price’s and Lotka’s law) were applied to these data. The results suggest a clear upward trend not only in the number of articles published since the 1970s (with a peak of productivity in 2010), but also in both the number of authors by article ( $ \bar{x} = 2. 7 5 $ , SD = 1.53) and internationalization, especially since the 1990s. The interest in meta-analysis extends to many authors (n = 5,445), countries (n = 44) and scientific journals (n = 394), as well as to several areas of psychology that mostly fit a growing exponential model. In future studies it would be interesting to explore the citing behaviour and patterns in the meta-analysis literature.  相似文献   
53.
The use of antimicrobial edible film is proposed as a means of improving food safety and extending the shelf-life of food systems by controlling the release of antimicrobials on food surfaces. In this work we first selected and studied 8 different essential oils (EOs) from plants, namely, oregano, clove, tea tree, coriander, mastic thyme, laurel, rosemary, and sage as natural antimicrobials against 2 gram-positive bacteria (Listeria innocua and Staphylococcus aureus) and 2 gram-negative bacteria (Salmonella enteritidis and Pseudomona fragi) by using the agar disk diffusion method. EOs from oregano, clove, and tea tree produced the largest surfaces of inhibition against the growth of the 4 bacterial strains tested. Second and following the assessment of compatibility, stable antimicrobial edible films based on whey protein isolate (WPI) with increasing concentrations (0.5% to 9%) of the 8 EOs were developed and tested for antimicrobial activity against the same gram-positive and gram-negative bacteria. WPI-edible films incorporating oregano or clove EO were found to have the most intense inhibitory effect of microbial growth. The bacterial strain gram-negative P. fragi presented the less susceptibility to the effect of those films. Moreover, only the edible films based on these 2 EOs were active against all 4 studied microorganisms. On the other hand, the edible films incorporating tea tree, coriander, mastic thyme, laurel, rosemary, or sage EOs even at high concentrations (7% to 9%) did not cause any antimicrobial effect against the pathogens S. aureus or S. enteritidis. PRACTICAL APPLICATION: Potential applications of this technology can introduce direct benefits to the food industry by improving safety and microbial product quality. The results of this research have direct application in the food industry with potential applications in various foodstuffs, including meat and poultry products where the control of spoilage bacteria such as P. fragi throughout their chilled storage or the improvement of food safety by controlling pathogens such as S. enteritidis are topics of particular interest for the industry.  相似文献   
54.
 The effect of waxy corn starch (WCS) on the texture, water-holding capacity and microstructure of sardine (Sardina pilchardus) surimi gels in two different systems was studied. In the type A system, increasing amounts of WCS (2, 4, 6 or 8 g/100 g surimi) were added to surimi while maintaining the gel moisture constant at 78%; in the type B system, WCS was added without correcting the gel moisture. Gels were made using two different heat treatments [heat-induced setting (HS) and direct cooking (DC)]. When starch was replaced by surimi (type A) and a heat treatment was applied that favoured formation of a preliminary actomyosin (AM) network (i.e. HS), gel strength (GS) was lower than in the control and decreased as more starch was added, despite an increase in the amount of water held by the gel. Scanning electron microscopy (SEM) showed that the matrix network was fibrillar with a globular surface. Starch appeared to be totally gelatinized and surrounded by a continuous matrix. When the amount of dry matter in gels was increased (type B), in no case did starch have a reinforcing effect, despite an increasing water-holding capacity; SEM showed a denser continuous matrix surrounding the gelatinized starch. Both types of gel made using the heat treatment that allows simultaneous gelling of surimi and gelatinization of starch (i.e. DC) exhibited much poorer GS than did HS gels, while addition of starch made practically no difference to gel texture. The findings suggest that the effect of starch is related to the type of gel matrix that forms upon addition of ingredients. Although such gels contained more water or dry matter, their texture parameters were lower, possibly because of the type of network formed by sardine surimi. Nonetheless, gels of acceptable quality were successfully made with added starch by incorporating less surimi. Received: 18 March 1996  相似文献   
55.
ABSTRACT: Providing consumers with basic taste properties of sweet cherries at point of purchase would allow consumers to make purchase decisions based on fruit's intrinsic sensory attributes. The objective of this study was to develop a model to predict taste-grouping assignation of cherries into the following categories: (1) low sweetness/high sourness, (2) balance between sweetness and sourness, and (3) high sweetness/low sourness. A sensory panel (n = 10) was trained to recognize sweetness and sourness in 5 cultivars of sweet cherries and assign a taste grouping based on the perceived balance of sweetness and sourness. Four of these same cultivars were then evaluated for sweetness and sourness by a consumer panel (n = 117) and instrumentally for titratable acidity (TA) and soluble solids concentration (SSC). Results showed that for 3 of the 4 cherry cultivars, the sweetness/sourness balance of the cherries was not significantly different as evaluated instrumentally or by the trained panel. However, the balance determined by the consumer and the trained panel was different for 3 of the 4 cherry cultivars (P < 0.05). Based on trained panel perceived sweetness and sourness, a multinomial logit model was developed to predict the assignation of cherry taste grouping. The likelihood of group assignment depended on both the perceived sweetness and sourness of the cherry, with taste groupings agreed upon for 3 of 5 sweet cherry cultivars. As previous studies have indicated a positive relationship between cherry sweetness and sourness to consumer acceptance, these groupings show promise for assisting consumers in cherry selection at the point of purchase. Practical Applications: The prediction models proposed in this study suggest that both sweetness and sourness are important in the cherry characterization and the ratio between the 2 attributes may be appropriate for making taste-grouping assignments. These groupings may then be used to provide additional sensory information to consumers to assist them in cherry selection at the point of purchase.  相似文献   
56.
Liu Ye  Maite Pijuan 《Water research》2010,44(9):2901-4682
Nitrite/Free Nitrous Acid (FNA) has previously been shown to inhibit aerobic and anoxic phosphate uptake by polyphosphate accumulating organisms (PAOs). The inhibitory effect of FNA on the aerobic metabolism of Glycogen Accumulating Organisms (GAOs) is investigated. A culture highly enriched (92 ± 3%) in Candidatus Competibacter phosphatis (hereafter called Competibacter) was used. The experimental data strongly suggest that FNA likely directly inhibits the growth of Competibacter, with 50% inhibition occurring at 1.5 × 10−3 mgN-HNO2/L (equivalent to approximately 6.3 mgN-NO2/L at pH 7.0). The inhibition is well described by an exponential function. The organisms ceased to grow at an FNA concentration of 7.1 × 10−3 mgN-HNO2/L. At this FNA level, glycogen production, another anabolic process performed by GAOs in parallel to growth, decreased by 40%, while the consumption of polyhydroxyalkanoates (PHAs), the intracellular carbon and energy sources for GAOs, decreased by approximately 50%. FNA likely inhibited either or both of the PHA oxidation and glycogen production processes, but to a much less extent in comparison to the inhibition on growth. The comparison of these results with those previously reported on PAOs suggest that FNA has much stronger inhibitory effects on the aerobic metabolism of PAOs than on GAOs, and may thus provide a competitive advantage to GAOs over PAOs in enhanced biological phosphorus removal (EBPR) systems.  相似文献   
57.
Agricultural application of sewage sludge has been emotionally discussed in the last decades, because the latter contains organic micropollutants with unknown fate and risk potential. In this work, the reuse of anaerobically digested sludge in agriculture is evaluated from an environmental point of view by using Life Cycle Assessment methodology. More specifically, the potential impacts of emerging micropollutants, such as pharmaceuticals and personal care products, present in the sludge have been quantified. Four scenarios were considered according to the temperature of the anaerobic digestion (mesophilic or thermophilic) and the sludge retention time (20 or 10 d), and they have been compared with the non-treated sludge.From an environmental point of view, the disposal of undigested sludge is not the most suitable alternative, except for global warming due to the dominance (65-85%) of the indirect emissions associated to the electricity use. Nutrient-related direct emissions dominate the eutrophication category impact in all the scenarios (>71.4%), although a beneficial impact related to the avoidance of industrial fertilisers production is also quantified (up to 6.7%). In terms of human and terrestrial toxicity, the direct emissions of heavy metals to soil dominate these two impact categories (>70%), and the contribution of other micropollutants is minimal. Moreover, only six (Galaxolide, Tonalide, Diazepam, Ibuprofen, Sulfamethoxazole and 17α-ethinyloestradiol) out of the 13 substances considered are really significant since they account for more than 95% of the overall micropollutants impact.  相似文献   
58.
The success of nanoparticle‐based therapies will depend in part on accurate delivery to target receptors and organs. There is, therefore, considerable potential in nanoparticles which achieve delivery of the right drug(s) using the right route of administration to the right location at the right time, monitoring the process by non‐invasive molecular imaging. A challenge is harnessing immunotherapy via activation of Toll‐like receptors (TLRs) for the development of vaccines against major infectious diseases and cancer. In immunotherapy, delivery of the vaccine components to lymph nodes (LNs) is essential for effective stimulation of the immune response. Although some promising advances have been made, delivering therapeutics to LNs remains challenging. It is here shown that iron‐oxide nanoparticles can be engineered to combine in a single and small (<50 nm) nanocarrier complementary multimodal imaging features with the immunostimulatory activity of polyinosinic‐polycytidylic acid (poly (I:C)). Whilst the fluorescence properties of the nanocarrier show effective delivery to endosomes and TLR3 in antigen presenting cells, MRI/SPECT imaging reveals effective delivery to LNs. Importantly, in vitro and in vivo studies show that, using this nanocarrier, the immunostimulatory activity of poly (I:C) is greatly enhanced. These nanocarriers have considerable potential for cancer diagnosis and the development of new targeted and programmable immunotherapies.  相似文献   
59.
A Mixed Line Rate (MLR) optical network is a good candidate for a core back-bone network because of its ability to provide diverse line rates to effectively accommodate traffic demands with heterogeneous bandwidth requirements. Because of the deleterious effects of physical impairments, there is a maximum transmission reach for optical signals before they have to be regener-ated. Being expensive devices, regenerators are expected to be sparsely located and used in such a network, called a translucent optical network. In this paper, we consider the Grooming, Routing, and Wavelength Assignment (GRWA) problem so that the Quality of Transmission (QoT) for connections is satisfied, and the network-level performance metric of blocking probability is minimized. Cross-layer heuristics to effectively allocate the sparse regenerators in MLR networks are developed, and extensive simulation results are presented to demonstrate their effectiveness.  相似文献   
60.
The availability of fresh water and the quality of aquatic ecosystems are important global concerns, and agriculture plays a major role. Consumers and manufacturers are increasingly sensitive to sustainability issues related to processed food products and drinks. The present study examines the production of sugar from the growing cycle through to processing to the factory gate, and identifies the potential impacts on water scarcity and quality and the ways in which the impact of water use can be minimised. We have reviewed the production phases and processing steps, and how calculations of water use can be complicated, or in some cases how assessments can be relatively straightforward. Finally, we outline several ways that growers and sugar processors are improving the efficiency of water use and reducing environmental impact, and where further advances can be made. This provides a template for the assessment of other crops. © 2013 Society of Chemical Industry  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号