全文获取类型
收费全文 | 3800篇 |
免费 | 131篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 52篇 |
综合类 | 59篇 |
化学工业 | 563篇 |
金属工艺 | 110篇 |
机械仪表 | 100篇 |
建筑科学 | 86篇 |
矿业工程 | 11篇 |
能源动力 | 146篇 |
轻工业 | 192篇 |
水利工程 | 15篇 |
石油天然气 | 15篇 |
武器工业 | 2篇 |
无线电 | 470篇 |
一般工业技术 | 707篇 |
冶金工业 | 965篇 |
原子能技术 | 15篇 |
自动化技术 | 459篇 |
出版年
2023年 | 23篇 |
2022年 | 54篇 |
2021年 | 71篇 |
2020年 | 39篇 |
2019年 | 43篇 |
2018年 | 52篇 |
2017年 | 59篇 |
2016年 | 68篇 |
2015年 | 50篇 |
2014年 | 90篇 |
2013年 | 244篇 |
2012年 | 176篇 |
2011年 | 184篇 |
2010年 | 150篇 |
2009年 | 173篇 |
2008年 | 150篇 |
2007年 | 139篇 |
2006年 | 153篇 |
2005年 | 113篇 |
2004年 | 98篇 |
2003年 | 83篇 |
2002年 | 72篇 |
2001年 | 69篇 |
2000年 | 69篇 |
1999年 | 94篇 |
1998年 | 281篇 |
1997年 | 188篇 |
1996年 | 184篇 |
1995年 | 110篇 |
1994年 | 90篇 |
1993年 | 77篇 |
1992年 | 50篇 |
1991年 | 52篇 |
1990年 | 53篇 |
1989年 | 57篇 |
1988年 | 52篇 |
1987年 | 33篇 |
1986年 | 39篇 |
1985年 | 32篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 18篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1977年 | 15篇 |
1976年 | 28篇 |
1975年 | 5篇 |
1972年 | 6篇 |
1970年 | 2篇 |
排序方式: 共有3967条查询结果,搜索用时 0 毫秒
41.
42.
Yao-Jen Chang Li-Der Chou Frank Tsen-Yung Wang Shu-Fang Chen 《Personal and Ubiquitous Computing》2013,17(2):351-358
Difficulties in executing daily living tasks hamper the quality of life of many individuals with cognitive impairments who are otherwise physically mobile. With sufficient and appropriate support on the job, many people with developmental disabilities and cognitive impairments are capable of participating in the world of work to various levels. Kinect is used as assistive technology for individuals with cognitive impairments to achieve the goal of performing task steps independently. In a community-based rehabilitation program under the guidance of three job coaches, a task prompting system called Kinempt was designed to assist four participants involving pre-service food preparation training. The study assessed the effectiveness of Kinempt in terms of precision and recall. A follow-up comparative study then evaluated a baseline method and the system of least prompts against the Kinempt system. Results indicate that for participants with cognitive disabilities, acquisition of job skills may be facilitated by use of Kinempt in conjunction with operant conditioning strategies. Our findings suggest that the image recognition technology may be able to facilitate task prompts needed by people with cognitive impairments. Therefore, the system may be helpful for pre-service training while increasing independence in the process of community integration. 相似文献
43.
44.
In this paper, we propose a scheme to integrate independent component analysis (ICA) and neural networks for electrocardiogram (ECG) beat classification. The ICA is used to decompose ECG signals into weighted sum of basic components that are statistically mutual independent. The projections on these components, together with the RR interval, then constitute a feature vector for the following classifier. Two neural networks, including a probabilistic neural network (PNN) and a back-propagation neural network (BPNN), are employed as classifiers. ECG samples attributing to eight different beat types were sampled from the MIT-BIH arrhythmia database for experiments. The results show high classification accuracy of over 98% with either of the two classifiers. Between them, the PNN shows a slightly better performance than BPNN in terms of accuracy and robustness to the number of ICA-bases. The impressive results prove that the integration of independent component analysis and neural networks, especially PNN, is a promising scheme for the computer-aided diagnosis of heart diseases based on ECG. 相似文献
45.
The structure of silica gels derived from tetraethoxysilane (TEOS) with molar compositions of TEOSH2OHNO3=1100.4 and then aged in various solvents, was studied. The effect of various solvents having different physical properties on the gel structure, as well as the relationship between the solvent properties and the dried gel structure, were investigated. The density, surface area and pore-size distribution were measured. The results of the pore structure and SEM showed the aged gels to have a slit-shaped micropore, narrow pore-size distribution, and homogeneous microstructure. The density, surface area, pore size and pore volume of dried gels changed as the gels were subjected to ageing in various solvents. The surface area could be related to the polarity parameter of the ageing solvent. 相似文献
46.
Process simulation and fabrication of advanced multi-step three-dimensional braided preforms 总被引:3,自引:0,他引:3
The fundamentals of multi-step braiding for the fabrication of three-dimensional fibre preforms for composites have been studied. To facilitate the understanding of the complex multi-step braiding processes, a computer simulation algorithm has been developed. The simulation acts as a tool to allow the identification of individual yarn paths, number and location of yarn groups, and braid geometry. It was found that individual control of the rows and columns of yarn carriers on a Cartesian braiding bed allows for the fabrication of advanced multi-step braids; the micro-structural possibilities of three-dimensional braids are thus greatly extended. Some basic relationships of the braiding parameters have been identified. It has been concluded that the traditional four-step and two-step braidings are special cases of multi-step braidings. To verify the feasibility of the structures, experimental investigations have also been carried out. Innovative braid architectures have been designed and fabricated using a prototype multi-step braiding machine. 相似文献
47.
Bo-Cheng Tao Wei Zhang Wen-Chieh Chou Fangyu Wang Yapeng Huang Yanan Li 《Journal of the Society for Information Display》2023,31(10):599-607
In this article, novel n-FFS liquid crystal material from Slichem was used in order to elevate the anti-backlight long aging effect; a trace amount of free radical trap HALS-like additive was added, the principle of which can be expressed via Denisov cycle, confirmed by measuring the temporal VHR changes in test cells; three different resolution (FHD ~ QHD) models paired with N19 and N21 were selected for testing by comparing the actual panel. It is verified that the optimized material greatly improves the image sticking performance of the panel and keeping optical performance. 相似文献
48.
Sodium-ion batteries have received remarkable attention as next-generation high-performance electrochemical energy storage devices because of their cost effectiveness and the broad geographical distribution of sodium. As a critical component of sodium-ion batteries, anode materials, especially nanostructured anodes, have a significant effect on the electrochemical performance of sodium-ion batteries. Recent research indicates that phosphorus and metal phosphides show great promise as anode candidates for sodium-ion batteries because of their low cost and relatively high theoretical gravimetric and volumetric specific capacities. In this review, we systematically summarize recent research progress on state-of-the-art nanostructured phosphorus and phosphides, including the synthetic strategies, Na-storage mechanisms, and the relationship between the nanostructure and electrochemical performance. Moreover, we present an overview of future challenges and opportunities based on current developments. 相似文献
49.
Researchers on organisational ambidexterity have proposed several solutions to address the potential conflicts between exploration activities and exploitation activities. Unlike simultaneous ambidexterity, sequential ambidexterity – defined as temporal switching between exploration and exploitation – has not been examined fully, and the conditions under which this temporal switching can be successful are unclear. This paper proposes the concept of temporal switching capability to better understand the process by which sequential ambidexterity is executed. In addition, we hypothesise that performance effects are contingent upon firm-specific factors: a firm’s business strategy and absorptive capacity. Utilising three sources of data – a secondary database, annual reports and a survey administered to 145 firms in the electronics industry with 10-year observations – we find support for our hypotheses. The results show that the temporal switching capability positively relates to new product performance and that business strategy type and absorptive capacity have moderating effects. The results are meaningful in both theory and practice. 相似文献
50.
Fine-needle aspiration is now accepted as the initial procedure for diagnosing a thyroid nodule. General pathologists inevitably will be asked to interpret aspirates as this diagnostic tool continues to be more widely used. This procedure is relatively inexpensive, is safe, and nearly always provides information useful in deciding how to manage the patient. We emphasize the importance of obtaining a representative sample of good quality. This often occurs when the "interventional pathologist" performs the aspirations, but there is no reason that another practitioner cannot become expert. Both histologic and cytologic features are reviewed from normal thyroid tissue, autoimmune thyroiditis, adenomatoid nodules, and follicular neoplasms. We encourage the use of clear, simple, and uniform terminology to facilitate communication. 相似文献