全文获取类型
收费全文 | 689篇 |
免费 | 185篇 |
国内免费 | 135篇 |
专业分类
电工技术 | 27篇 |
综合类 | 74篇 |
化学工业 | 5篇 |
金属工艺 | 1篇 |
机械仪表 | 12篇 |
建筑科学 | 46篇 |
矿业工程 | 4篇 |
能源动力 | 6篇 |
轻工业 | 9篇 |
水利工程 | 73篇 |
石油天然气 | 1篇 |
武器工业 | 3篇 |
无线电 | 87篇 |
一般工业技术 | 32篇 |
冶金工业 | 153篇 |
自动化技术 | 476篇 |
出版年
2024年 | 7篇 |
2023年 | 42篇 |
2022年 | 76篇 |
2021年 | 72篇 |
2020年 | 64篇 |
2019年 | 33篇 |
2018年 | 45篇 |
2017年 | 38篇 |
2016年 | 34篇 |
2015年 | 26篇 |
2014年 | 36篇 |
2013年 | 35篇 |
2012年 | 40篇 |
2011年 | 39篇 |
2010年 | 40篇 |
2009年 | 39篇 |
2008年 | 44篇 |
2007年 | 49篇 |
2006年 | 38篇 |
2005年 | 51篇 |
2004年 | 36篇 |
2003年 | 26篇 |
2002年 | 37篇 |
2001年 | 20篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1988年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1964年 | 2篇 |
1960年 | 2篇 |
1958年 | 1篇 |
排序方式: 共有1009条查询结果,搜索用时 15 毫秒
81.
Murugan Arunachalam Sabeenian Royappan Savarimuthu 《International journal of imaging systems and technology》2019,29(1):65-76
In recent years, mortality rate with high-grade tumor has been increased significantly especially with glioblastoma (GBM) brain tumor while compared to other malignant brain tumor. Here, the amount of dead cells accommodated with the tumor tissue in GBM brain tumor play a vital task and necessitate an earlier diagnosis of malignancy with the GBM tumor. It inspires to implement new automatic diagnosis system which detects the dead cells and tumor tissue with the GBM brain tumor, such that the survival rate of the diseased can easily be prognosis by the Radiologist and Neurosurgeon. The main objective of this article is to detect the amount of dead cells with respect to tumor tissue associated with the GBM brain tumor which desires the impact factor of the brain tumor. In this framework, initially, the new contrast enhancement modality is incorporated to enhance the gray information over the dead cells and the tumor tissue with the T1-weighted MRI GBM brain tumor. In this enhancement, the edges of the tumor cells and its dead cells are magnified efficiently. As the noises and outliers with MR image is unpredictable and it experiences the variable amount of noises over the local window, the contextual information over each pixel of the image is adaptively modified with respect to the amount of noise over local window using adaptive contextual clustering. The performance evaluation of the framework is investigated which exhibits the overwhelming result compared to conventional detection techniques. 相似文献
82.
Vijaya Sunder M 《国际生产研究杂志》2020,58(16):4894-4915
Organisations implement various Continuous Improvement (CI) practices such as Total Quality Management, Lean, Six Sigma and Lean Six Sigma (LSS) for improving their processes. Drawing from the success and failure stories of these structured CI practices, scholars enumerated Critical Success Factors and Critical Failure Factors (CFFs). This study empirically examines the occurrence of various CFFs across different stages of CI deployment. Further, from a contingency theoretic perspective, this study investigates their associations with contextual variables by collecting survey data from 213 business units from the USA, the UK, China, and India. Principal Component Analysis is used to group CFFs across five CI deployment stages leading to an empirically refined framework for CI. Crosstab analysis using the chi-square likelihood ratio presented associations of CFFs with contextual variables. Findings reveal significant differences in the occurrence of CFFs across countries. There is evidence that LSS is less prone to failures when compared with TQM, Lean and Six Sigma. The occurrence of CFFs has been relatively lower in smaller and medium-sized enterprises operating in the service sector. Findings also reveal that lessons learned from each CI deployment cycle, contribute to organisational learning, and thence, leading to success at the strategic CI level of maturity. 相似文献
83.
Shaoqi Gong Daniel F. T. Hagan Xinyi Wu Guojie Wang 《International journal of remote sensing》2018,39(10):3094-3110
Northwest China is considered as the arid and semi-arid temperate continental climate, where the precipitation is closely related to precipitable water vapour (PWV) content. In this paper, the Medium-Resolution Spectral Imager (MERSI) water vapour products were first used to study the spatial and temporal characteristics of water vapour over Northwest China, which were developed by the National Satellite Meteorological Center of China from the Chinese second-generation polar orbit Meteorological Satellite Fengyun 3A (FY-3A). In order to utilize the MERSI water vapour products, the MERSI 5 min water vapour product is compared respectively with global positioning system (GPS), Aerosol Robotic Network (AERONET) and Radiosonde water vapour data in situ datasets. The results show that the water vapour values of the MERSI product are a slightly lower than referenced data, and the accuracy of MERSI product compared with GPS water vapour is the most agreeable, with a mean absolute percentage error (MAPE) of 22.83%. The PWV content displays a typical spatial distribution pattern in Northwest China that it is the highest in the southeast, the second for the northwest and the lowest in the south-centre. The water vapour content over each province in a descending order is Shaanxi, Ningxia, west of Inner Mongolia, Xinjiang, Gansu and Qinghai. The seasonal variation of water vapour content over Northwest China appears to be lowest in winter, followed by spring, then for autumn, and highest in summer. The PWV content of each province in Northwest China shows the periodic inner-annual variation, that is, the PWV content is lowest in January, and gradually increases with time till it peaks in July, and then decreases monthly afterwards, which agrees with the quadratic polynomial model by months. The standard deviation of the water vapour content in summer is 0.533–1.027 mm, while that in winter is 0.262–0.527 mm. 相似文献
84.
《Journal of Urbanism》2013,6(1):7-8
The objective of this study was to obtain empirical data on how well various contextual urban design principles work and thus assist in formulating evidence‐based planning. This paper reports findings from three studies, covering 51 environments and 164 participants, on how strongly these factors were related to visual appeal of a whole block of houses: (a) individual style of an infill house; (b) number of matches between an infill house and the houses in their contexts; (c) the diversity of the existing context; (d) proximity of an infill house to other houses; and (e) compatibility of the infill house with respect to the houses in their contexts. The strongest effect was found for the individual style of a new building, followed by the equivalence of judgments of compatibility and visual appeal, by the number of other houses the infill house matched, by existing visual diversity, and by distance. Policy guidance is provided for effects sufficiently strong to support evidence‐based decision making and withheld for effects for which the scientific support is currently insufficient. 相似文献
85.
针对传统密集轨迹方法应用到真实场景后过多无效轨迹耗费存储与计算资源且严重影响有效特征提取的不足,提出一种新的人体行为识别算法。首先,检测视频帧中存在的人体目标并对获得的包含人体的矩形框进行扩展,利用扩展后的矩形框对传统密集采样特征点的范围进行筛选限制;然后,对筛选限制后的特征点在光流场中跟踪一定帧数获取限制密集轨迹,并在以限制密集轨迹为中心的时空体内构建一组包含轨迹的空间位置、时空上下文信息的特征描述子;最后在视觉词袋模型框架下,采用SVM对特征向量进行编码分类。结果显示:在KTH、YouTube和HMDB51 3个行为数据库上的识别准确率分别达到98.1%、89.7%和66.9%。证明本算法对复杂真实场景中的人体行为具有较高的识别能力。 相似文献
86.
《Journal of Location Based Services》2013,7(2):138-166
With the prevalence of mobile computing systems and location based services, large amounts of spatio-temporal data are nowadays being collected, representing the mobility of people performing various activities. However, despite the increasing interest in the exploration of these data, there are still open challenges in various application contexts, e.g. related to visualisation and human–computer interaction. In order to support the extraction of useful and relevant information from the spatio-temporal and the thematic properties associated with human trajectories, it is crucial to develop and study adequate interactive visualisation techniques. In addition to the properties of the visualisations themselves, it is important to take into consideration the types of information present within the data and, more importantly, the types of tasks that a user might need to consider in order to achieve a given goal. The understanding of these factors may, in turn, simplify the development and the assessment of a given interactive visualisation. In this paper, we present and analyse the most relevant concepts associated to these topics. In particular, our analysis addresses the main properties associated with (human) trajectory data, the main types of visualisation tasks/objectives that the users may require in order to analyse that data and the high-level classes of techniques for visualising trajectory data. In addition, this paper also presents an overview on a user study, conducted in function of this analysis, to compare two classes of visualisation techniques, namely static maps and space-time cubes, regarding their adequacy in helping users completing basic visualisation tasks. 相似文献
87.
The present study examined the relationship between a set of individual and contextual variables and high-risk alcohol use among young offenders placed on community orders in New South Wales, Australia. Participants (n = 777) were compared on a set of factors known to be strong predictors of high-risk alcohol use among adolescents. The authors assessed the strength of the relationship between gender, age, ethnicity, geographical region of residence, school attendance, father absence, history of childhood trauma, and the presence of severe conduct disorder on weekly levels of alcohol use. Living in rural locations, not currently attending school, being female, and not having been raised with a biological father present were associated with significantly increased odds of alcohol abuse. Father absence was a more important risk factor for rural young offenders, but school dropout was associated with more hazardous drinking among young offenders in urban areas. Accordingly, the authors suggest family-focused intervention programs for young offenders living in rural areas and school-based programs for vulnerable young people living in urban areas, although programs should consider including both factors for both groups if feasible and warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
88.
Hand Christopher J.; Miellet Sébastien; O'Donnell Patrick J.; Sereno Sara C. 《Canadian Metallurgical Quarterly》2010,36(5):1294
A word's frequency of occurrence and its predictability from a prior context are key factors determining how long the eyes remain on that word in normal reading. Past reaction-time and eye movement research can be distinguished by whether these variables, when combined, produce interactive or additive results, respectively. Our study addressed possible methodological limitations of prior experiments. Initial results showed additive effects of frequency and predictability. However, we additionally examined launch site (the distance from the pretarget fixation to the target) to index the extent of parafoveal target processing. Analyses revealed both additive and interactive effects on target fixations, with the nature of the interaction depending on the quality of the parafoveal preview. Target landing position and pretarget fixation time were also considered. Results were interpreted in terms of models of language processing and eye movement control. Our findings with respect to parafoveal preview and fixation time constraints aim to help parameterize eye movement behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
89.
The authors report results from 2 studies assessing the extent to which narcissism is related to self- and other ratings of leadership, workplace deviance, and task and contextual performance. Study 1 results revealed that narcissism was related to enhanced self-ratings of leadership, even when controlling for the Big Five traits. Study 2 results also revealed that narcissism was related to enhanced leadership self-perceptions; indeed, whereas narcissism was significantly positively correlated with self-ratings of leadership, it was significantly negatively related to other ratings of leadership. Study 2 also revealed that narcissism was related to more favorable self-ratings of workplace deviance and contextual performance compared to other (supervisor) ratings. Finally, as hypothesized, narcissism was more strongly negatively related to contextual performance than to task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
90.
我们首先分析了时空数据库事务的特点,然后在BT2D-Index的基础上提出了时空数据库事务并发控制的动态封锁方法,并且对动态封锁中几个重要概念做了说明,给出了动态封锁的具体操作,最后对这种动态封锁方法进行了评价。 相似文献