全文获取类型
收费全文 | 1217篇 |
免费 | 97篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 318篇 |
金属工艺 | 23篇 |
机械仪表 | 28篇 |
建筑科学 | 46篇 |
矿业工程 | 5篇 |
能源动力 | 38篇 |
轻工业 | 190篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 149篇 |
一般工业技术 | 223篇 |
冶金工业 | 49篇 |
原子能技术 | 6篇 |
自动化技术 | 217篇 |
出版年
2024年 | 3篇 |
2023年 | 15篇 |
2022年 | 31篇 |
2021年 | 34篇 |
2020年 | 33篇 |
2019年 | 49篇 |
2018年 | 54篇 |
2017年 | 34篇 |
2016年 | 67篇 |
2015年 | 45篇 |
2014年 | 63篇 |
2013年 | 114篇 |
2012年 | 80篇 |
2011年 | 90篇 |
2010年 | 60篇 |
2009年 | 69篇 |
2008年 | 74篇 |
2007年 | 38篇 |
2006年 | 43篇 |
2005年 | 39篇 |
2004年 | 30篇 |
2003年 | 31篇 |
2002年 | 28篇 |
2001年 | 15篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 20篇 |
1997年 | 20篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 16篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有1314条查询结果,搜索用时 31 毫秒
51.
Patricia Perez-Fuster Maria F. Rodrigo Maria Luisa Ballestar Jaime Sanmartin 《Accident; analysis and prevention》2013
In relative terms, Spanish motorcyclists are more likely to be involved in crashes than other drivers and this tendency is constantly increasing. The objective of this study is to identify the factors that are related to being an offender in motorcycle accidents. A binary logit model is used to differentiate between offender and non-offender motorcyclists. A motorcyclist was considered to be offender when s/he had committed at least one traffic offense at the moment previous to the crash. The analysis is based on the official accident database of the Spanish general directorate of traffic (DGT) for the 2003–2008 time period. A number of explanatory variables including motorcyclist characteristics and environmental factors have been evaluated. The results suggest that inexperienced, older females, not using helmets, absent-minded and non-fatigued riders are more likely to be offenders. Moreover, riding during the night, on weekends, for leisure purposes and along roads in perfect condition, mainly on curves, predict offenses among motorcyclists. The findings of this study are expected to be useful in developing traffic policy decisions in order to improve motorcyclist safety. 相似文献
52.
53.
54.
It is widely accepted that biotechnology is a globally significant and growing research field. Because of its biodiversity, Colombia has a comparative advantage to innovate and commercialize biotechnological products and services. The aim of this study is to obtain a research profile and intellectual structure of the country in the biotechnology field by using bibliometric methods. These methods are needed to monitor the capacities and the compliance of national policies in biotechnology. By using records extracted from the ISI WoK database, this study describes the biotechnology publication trend, productivity and collaboration among institutions and countries, preferred journals, and the intellectual structure at the research subject area. Although, a growing trend in biotechnology publication was observed, the productivity is still low when compared to other countries in the region and the world. On the other hand, researchers seem to show a preference for international over domestic collaboration. The results suggest two elements: first, policy has not had the expected outcome in the short term, and second, a lack of internal collaboration could therefore reflect low endogenous capacities. The bibliometric methods used in this study can be applied to a wide range of research fields other than biotechnology. 相似文献
55.
Using Combined Bipolar Semantic Scales and Eye‐Tracking Metrics to Compare Consumer Perception of Real and Virtual Bottles
下载免费PDF全文
![点击此处可从《Packaging Technology and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Juan‐Carlos Rojas Manuel Contero Noemí Bartomeu Jaime Guixeres 《Packaging Technology and Science》2015,28(12):1047-1056
Three‐dimensional virtual representations of consumer products are expected to gain relevance in e‐commerce applications as low cost virtual reality headsets arrive on the market in the next years. However, there are a limited number of studies related to the perceptual evaluation of virtual products and their packaging where virtual and real (photographic) representations are compared. As part of an extensive exploration toward understanding product perception in virtual stores, this work presents a study with 38 participants in which consumer perceptions of a photographic and a virtual representation of a beer bottle are examined. Perceptual evaluation is assessed using two metrics: first, an evaluation was performed by applying a bipolar semantic scale based on four axes: novelty, resolution, style and emotion. Second, eye‐tracking metrics were employed to analyse participant gaze behaviour during the visualization of stimuli. Virtual bottles were modelled using a medium polygonal load (5 K polygons per bottle), and render quality was also medium to intentionally recreate the computing limitations of smartphone‐based virtual reality headsets. Results show that a medium render quality alters consumer perception and responses using semantic scales. Eye‐tracking analysis confirms that the orientation of the bottle and how it is presented also affect consumer perception. While some orientations result in similar eye‐tracking metrics, others show different results. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
56.
57.
Mohammed S. Shafae Rebecca M. Dickinson William H. Woodall Jaime A. Camelio 《Quality and Reliability Engineering International》2015,31(5):839-849
The Weibull distribution can be used to effectively model many different failure mechanisms due to its inherent flexibility through the appropriate selection of a shape and a scale parameter. In this paper, we evaluate and compare the performance of three cumulative sum (CUSUM) control charts to monitor Weibull‐distributed time‐between‐event observations. The first two methods are the Weibull CUSUM chart and the exponential CUSUM (ECUSUM) chart. The latter is considered in literature to be robust to the assumption of the exponential distribution when observations have a Weibull distribution. For the third CUSUM chart included in this study, an adjustment in the design of the ECUSUM chart is used to account for the true underlying time‐between‐event distribution. This adjustment allows for the adjusted ECUSUM chart to be directly comparable to the Weibull CUSUM chart. By comparing the zero‐state average run length and average time to signal performance of the three charts, the ECUSUM chart is shown to be much less robust to departures from the exponential distribution than was previously claimed in the literature. We demonstrate the advantages of using one of the other two charts, which show surprisingly similar performance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
58.
Chalissery Jaime M. Gries Regine Alamsetti Santosh K. Ardiel Madison J. Gries Gerhard 《Journal of chemical ecology》2022,48(3):302-311
Journal of Chemical Ecology - Four species of Tetramorium pavement ants are known to guide foraging activities of nestmates via trail pheromones secreted from the poison gland of worker ants, but... 相似文献
59.
Effect of mixer geometry and operating conditions on flow mixing of shear thinning fluids with yield stress
下载免费PDF全文
![点击此处可从《American Institute of Chemical Engineers》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jaime Sossa‐Echeverria Fariborz Taghipour 《American Institute of Chemical Engineers》2014,60(3):1156-1167
Flow mixing of a non‐Newtonian fluid in a stirred tank equipped with a side‐entry impeller was observed using particle image velocimetry (PIV). The effects of some geometrical parameters including the mixer shape and impeller type and position on the flow pattern were studied on velocity fields obtained at different locations inside the mixing domain. The different flow structures revealed that the ratio of inertial and viscous forces largely defines the flow pattern. Dead zones were observed inside the tank due to the rheological properties of the fluid. The size of the dynamic regions and the average velocity near the impeller were enhanced by increasing the suction area. Likewise, large pitch ratios were found to improve the active mixing zone and the axial discharge. Curves for the power and pumping numbers are reported for different axial flow impellers. © 2013 American Institute of Chemical Engineers AIChE J, 60: 1156–1167, 2014 相似文献
60.
Christina Jane Vellan Jaime Jacqueline Jayapalan Boon-Koon Yoong Azlina Abdul-Aziz Sarni Mat-Junit Perumal Subramanian 《International journal of molecular sciences》2022,23(4)
Pancreatic ductal adenocarcinoma (PDAC), a highly aggressive malignancy with a poor prognosis is usually detected at the advanced stage of the disease. The only US Food and Drug Administration-approved biomarker that is available for PDAC, CA 19-9, is most useful in monitoring treatment response among PDAC patients rather than for early detection. Moreover, when CA 19-9 is solely used for diagnostic purposes, it has only a recorded sensitivity of 79% and specificity of 82% in symptomatic individuals. Therefore, there is an urgent need to identify reliable biomarkers for diagnosis (specifically for the early diagnosis), ascertain prognosis as well as to monitor treatment response and tumour recurrence of PDAC. In recent years, proteomic technologies are growing exponentially at an accelerated rate for a wide range of applications in cancer research. In this review, we discussed the current status of biomarker research for PDAC using various proteomic technologies. This review will explore the potential perspective for understanding and identifying the unique alterations in protein expressions that could prove beneficial in discovering new robust biomarkers to detect PDAC at an early stage, ascertain prognosis of patients with the disease in addition to monitoring treatment response and tumour recurrence of patients. 相似文献