全文获取类型
收费全文 | 5191篇 |
免费 | 377篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 34篇 |
综合类 | 1篇 |
化学工业 | 894篇 |
金属工艺 | 87篇 |
机械仪表 | 89篇 |
建筑科学 | 151篇 |
矿业工程 | 7篇 |
能源动力 | 88篇 |
轻工业 | 975篇 |
水利工程 | 62篇 |
石油天然气 | 14篇 |
无线电 | 224篇 |
一般工业技术 | 798篇 |
冶金工业 | 1403篇 |
原子能技术 | 14篇 |
自动化技术 | 730篇 |
出版年
2024年 | 5篇 |
2023年 | 37篇 |
2022年 | 33篇 |
2021年 | 98篇 |
2020年 | 95篇 |
2019年 | 117篇 |
2018年 | 187篇 |
2017年 | 191篇 |
2016年 | 212篇 |
2015年 | 174篇 |
2014年 | 225篇 |
2013年 | 427篇 |
2012年 | 329篇 |
2011年 | 317篇 |
2010年 | 233篇 |
2009年 | 233篇 |
2008年 | 233篇 |
2007年 | 220篇 |
2006年 | 113篇 |
2005年 | 98篇 |
2004年 | 114篇 |
2003年 | 93篇 |
2002年 | 103篇 |
2001年 | 76篇 |
2000年 | 64篇 |
1999年 | 79篇 |
1998年 | 536篇 |
1997年 | 294篇 |
1996年 | 193篇 |
1995年 | 96篇 |
1994年 | 78篇 |
1993年 | 74篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 22篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 19篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 19篇 |
1976年 | 28篇 |
1970年 | 1篇 |
排序方式: 共有5571条查询结果,搜索用时 31 毫秒
101.
The common multichannel system for recognizing colored images is replaced by a color-encoded single-channel system. Amethod inspired by the Munsell color system is used for encoding the different colors as phase and amplitude functions. It is shown that for many practical cases the phase information part of the color code is sufficient for obtaining good results. An implementation based on a liquid-crystal television panel that works in a phase-modulation mode is suggested. Computer simulations that demonstrate the capabilities of the suggested method are given as well as a comparison with previously published multichannel performance. 相似文献
102.
Naturally contaminated beef-brisket fat showed a psychrotroph count of 4 × 10(9) CFU/cm(2) after 14 days of aerobic refrigerated storage (5°C ± 1°C). Pseudomonas was the predominating genus. Other micro-organisms, such as Enterobacteriaceae and Brochothrix thermosphacta, grew up to 2·5 × 10(8) cfu/cm(2) and 1·6 × 10(8) cfu/cm(2), respectively. Concentrations of different substrates that could support microbial growth were measured. Glucose concentration dropped to approximately one-third of the initial level during the first week of storage. Lactic acid also declined. Free fatty acids increased significantly (P < 0·05) during refrigeration. However, other lipid-deterioration indices, such as the thiobarbituric acid number and the peroxide value, remained unchanged. Beef subcutaneous fat had a high initial microbial load and a capacity to support extensive bacterial growth. It may therefore constitute an important source of contamination for meat and manufactured meat products. 相似文献
103.
Cáceres-Criado Irene García-Molina Diego Francisco Mesas-Carrascosa Francisco Javier Triviño-Tarradas Paula 《Virtual Reality》2023,27(2):967-983
Virtual Reality - Virtual reconstruction is defined as the visual recovery of a building or object through the creation of a three-dimensional model of the asset to be reconstructed, in a... 相似文献
104.
Andres Amador García-Granada Giovanni Gomez-Gras Ramón Jerez-Mesa Guillermo Reyes 《Materials and Manufacturing Processes》2017,32(11):1279-1289
Ball-burnishing induces compressive residual stresses on treated materials by the effect of plastic deformation. The result is an increase in the fatigue life of the treated part, retarding the initiation of cracks on the surface. Compressive residual stresses have been previously measured by X-ray diffraction near the surface, revealing considerably high values at the maximum analyzed depth, in relation to other finishing processes such as shot peening. However, the maximum analyzed depth is very limited by using this technique. In this paper, the incremental hole drilling (IHD) technique is tested to measure residual stresses, being able to reach a 2-mm measuring depth. To that objective, a commercial strain gage is used and calibrated using finite element model simulations. A second Finite Element Model based on material removal rate is developed to obtain the equations to calculate the strain release through IHD. Finally, residual stresses are measured experimentally with that technique on two different materials, confirming that ball-burnishing increases the compressive residual stresses in layers up to 0.5?mm deep for the testing conditions, which is a good response to industrial needs. The method proves to be suitable, simple and inexpensive way to measure the value of these tensions. 相似文献
105.
106.
Sandra García‐Bustos Mónica Mite Francisco Vera 《Quality and Reliability Engineering International》2016,32(5):1741-1755
This article analyzes the simultaneous control of several correlated Poisson variables by using the Variable Dimension Linear Combination of Poisson Variables (VDLCP) control chart, which is a variable dimension version of the LCP chart. This control chart uses as test statistic, the linear combination of correlated Poisson variables in an adaptive way, i.e. it monitors either p1 or p variables (p1 < p) depending on the last statistic value. To analyze the performance of this chart, we have developed software that finds the best parameters, optimizing the out‐of‐control average run length (ARL) for a shift that the practitioner wishes to detect as quickly as possible, restricted to a fixed value for in‐control ARL. Markov chains and genetic algorithms were used in developing this software. The results show performance improvement compared to the LCP chart. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
107.
Thermal Scanning at the Cellular Level by an Optically Trapped Upconverting Fluorescent Particle 下载免费PDF全文
108.
109.
Carlos A. García-Velásquez Valentina Aristizábal-Marulanda Carlos A. Cardona 《Clean Technologies and Environmental Policy》2018,20(7):1599-1613
In this paper, a techno-economic and environmental assessment is performed to compare the stand-alone process and biorefinery ways to produce biodiesel, ethanol and butanol as potential cases for bioenergy production using fresh fruit bunches as raw material. Different levels of integration are considered (e.g., mass and energy integration, non-conventional technologies) along with the analysis of the process scale to determine the economic profitability and environmental impacts of the proposed cases. The results demonstrated that the biodiesel production based on the biorefinery concept has a positive effect on the profitability of the stand-alone process at different scales. The economic results were compared with data reported in the literature. Furthermore, the life cycle analysis of the proposed cases suggested that the deployment of the biorefinery concept at different levels of integration in the oil palm supply chain reduced the environmental impact of the biodiesel production, which was selected as the hotspot of the evaluated cases. 相似文献
110.
A Camacho Ojeda E Llanes Montero C García Requena M Romero Corchero 《Canadian Metallurgical Quarterly》1998,21(235):17-20
The quality of care within our health care system depends upon an active and dynamic communication which bridges the different levels of care (primary and hospital) and will permit a continuity of services between the distinct parts. To insure this success, the authors propose an outpatient nursing record that will follow the patient upon his or her discharge. This record, to be called the "Discharged Patient Report", will be directed to other medical professionals so that they can be informed of previous treatments that the patient has received. Included in the report will be items such as; the previous nursing interactions that were used on the patient, how problems were resolved, possible other solutions, and health care information given to the patient. Using the report in this way will give us a great tool to know our patients and better understand how to serve them. 相似文献