全文获取类型
收费全文 | 134061篇 |
免费 | 4052篇 |
国内免费 | 564篇 |
专业分类
电工技术 | 1520篇 |
综合类 | 2376篇 |
化学工业 | 21906篇 |
金属工艺 | 6711篇 |
机械仪表 | 5996篇 |
建筑科学 | 3287篇 |
矿业工程 | 586篇 |
能源动力 | 3357篇 |
轻工业 | 7665篇 |
水利工程 | 1539篇 |
石油天然气 | 431篇 |
武器工业 | 3篇 |
无线电 | 17512篇 |
一般工业技术 | 27644篇 |
冶金工业 | 6821篇 |
原子能技术 | 951篇 |
自动化技术 | 30372篇 |
出版年
2023年 | 592篇 |
2022年 | 630篇 |
2021年 | 1608篇 |
2020年 | 1178篇 |
2019年 | 1290篇 |
2018年 | 15550篇 |
2017年 | 14492篇 |
2016年 | 11522篇 |
2015年 | 2028篇 |
2014年 | 2539篇 |
2013年 | 3546篇 |
2012年 | 6546篇 |
2011年 | 13253篇 |
2010年 | 10961篇 |
2009年 | 8551篇 |
2008年 | 9461篇 |
2007年 | 9876篇 |
2006年 | 2342篇 |
2005年 | 3029篇 |
2004年 | 2802篇 |
2003年 | 2738篇 |
2002年 | 1943篇 |
2001年 | 1324篇 |
2000年 | 1273篇 |
1999年 | 1075篇 |
1998年 | 1778篇 |
1997年 | 1118篇 |
1996年 | 932篇 |
1995年 | 606篇 |
1994年 | 525篇 |
1993年 | 454篇 |
1992年 | 334篇 |
1991年 | 318篇 |
1990年 | 278篇 |
1989年 | 263篇 |
1988年 | 227篇 |
1987年 | 177篇 |
1986年 | 132篇 |
1985年 | 122篇 |
1984年 | 102篇 |
1983年 | 74篇 |
1982年 | 42篇 |
1981年 | 42篇 |
1977年 | 46篇 |
1976年 | 70篇 |
1968年 | 48篇 |
1966年 | 48篇 |
1965年 | 46篇 |
1955年 | 64篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
81.
82.
Kim Geonu Kacar Yilmaz Pistorius Petrus Christiaan 《Metallurgical and Materials Transactions B》2019,50(6):2508-2516
Metallurgical and Materials Transactions B - The concentration and chemical bonding state of carbon in direct-reduced iron (DRI) might affect DRI melting temperature and rate. The effects of carbon... 相似文献
83.
Yachao Dong Christos T. Maravelias Norman F. Jerome 《Optimization and Engineering》2018,19(4):937-976
We study a maritime inventory routing problem, in which shipments between production and consumption nodes are carried out by a fleet of vessels. The vessels have specific capacities and can be chartered under different agreements. The inventory levels of all consumption nodes and some production nodes should be maintained within specified bounds; for the remaining production nodes, orders should be picked up within pre-defined time windows. We propose a discrete-time mixed-integer programming model. In the face of new information and uncertainty, this optimization model has to be re-solved, as the horizon is rolled forward. We discuss how to account for different sources of uncertainty. We present a rolling-horizon reoptimization framework that allows us to study different policies that impact the quality of the implemented solution, so we can identify the optimal set of policies. 相似文献
84.
Seong‐Hee Kim 《Quality and Reliability Engineering International》2015,31(6):923-934
We present a distribution‐free tabular cumulative sum chart for monitoring the variability of an autocorrelated process. A quantity known as the asymptotic variance parameter is employed as a measure of the variability, and a distribution‐free tabular cumulative sum chart is applied to variance estimates calculated from batches of nonoverlapping samples. The proposed chart is applicable to a stationary process with a general marginal distribution and a general autocorrelation structure. It also determines control limits analytically without trial‐and‐error simulations. The performance of the proposed chart is tested on stationary processes with both normal and nonnormal marginals with various autocorrelation structures. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
85.
Inam Ridha Ali Basiri Sudhakar Godeshala Md Zubair Ebne Rafique Deepanjan Ghosh Jason Williams Nikhilesh Chawla Jung Keun Lee Jacquelyn Kilbourne Yu Yao Kaushal Rege 《Advanced functional materials》2021,31(6):2007811
Poor strength, infection, leakage, long procedure times, and inflammation limit the efficacy of common tissue sealing devices in surgeries and trauma. Light-activated sealing is attractive for tissue sealing and repair, and can be facilitated by the generation of local heat following absorption of nonionizing laser energy by chromophores. Here, the inherent ability of biomaterials is exploited to absorb nonionizing, mid-infrared (midIR) light in order to engender rapid photothermal sealing and repair of soft tissue wounds. In this approach, the biomaterial simultaneously acts as a photothermal convertor as well as a biosealant, which dispenses the need for exogeneous light-absorbing nanoparticles or dyes. Biomechanical recovery, mathematical modeling, histopathology analyses, tissue strain mapping using digital imaging correlation, and visualization of the biosealant-tissue interface using hyperspectral imaging indicate superior performance of midIR sealing in live mice compared to conventional sutures and glue. The midIR-biosealant approach demonstrates rapid sealing of soft tissues, improves cosmesis, lowers potential for scarring, obviates safety concerns because of the nonionizing light used, and allows adoption of a wide diversity of biomaterials. Taken together, the studies demonstrate a novel advance both in biomaterials for surgical sealing along with the use of nonionizing midIR light, with high potential for clinical translation. 相似文献
86.
87.
Oh Seung-Jun Yoon Jeong-Hwan Kim Si-Pom 《Journal of Mechanical Science and Technology》2021,35(3):1065-1073
Journal of Mechanical Science and Technology - In the industry, globe valves, which are commonly used to precise control the flow rate along with opening and closing flow in pipes, are technically... 相似文献
88.
Jinho Choi Sanghun Jung Deok Gun Park Jaegul Choo Niklas Elmqvist 《Computer Graphics Forum》2019,38(3):249-260
The majority of visualizations on the web are still stored as raster images, making them inaccessible to visually impaired users. We propose a deep‐neural‐network‐based approach that automatically recognizes key elements in a visualization, including a visualization type, graphical elements, labels, legends, and most importantly, the original data conveyed in the visualization. We leverage such extracted information to provide visually impaired people with the reading of the extracted information. Based on interviews with visually impaired users, we built a Google Chrome extension designed to work with screen reader software to automatically decode charts on a webpage using our pipeline. We compared the performance of the back‐end algorithm with existing methods and evaluated the utility using qualitative feedback from visually impaired users. 相似文献
89.
Ha-Nul Lee Joo-Hee Choi Ji-Yeon Park Jae-Hun Ahn Da Eun Jang Jae Gun Shim Jong-Hwan Park Young-Min Kim 《Food science and biotechnology》2021,30(4):583
Vegetable soup (VS), a plant-based functional food, has been used as a traditional folk medicine and is attracting attention for its ability to enhance the immune response. β-Glucan, a well-established and effective immunomodulator, has synergistic effects when used in combination with some bioactive compounds. In the present study, we aimed to evaluate the synergistic immunomodulatory effects of the combination of VS and β-glucan on macrophage-mediated immune responses. β-Glucan was demonstrated to synergistically enhance the VS-stimulated immune response, including the production of interleukin-6, tumor necrosis factor-α, and nitric oxide, mainly through the mitogen-activated protein kinase pathway in macrophages. In addition, this combination has the potential for further development in functional foods with immune-enhancing activity.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-021-00888-x. 相似文献
90.
Food Science and Biotechnology - St. Paul’s Wort (Siegesbeckia orientalis L.) confers anti-oxidative, anti-inflammatory, anti-allergic, anti-infertility, and immunosuppressive properties.... 相似文献