全文获取类型
收费全文 | 137261篇 |
免费 | 3398篇 |
国内免费 | 605篇 |
专业分类
电工技术 | 1610篇 |
综合类 | 2399篇 |
化学工业 | 21539篇 |
金属工艺 | 6534篇 |
机械仪表 | 5675篇 |
建筑科学 | 3355篇 |
矿业工程 | 607篇 |
能源动力 | 3237篇 |
轻工业 | 7455篇 |
水利工程 | 1505篇 |
石油天然气 | 551篇 |
武器工业 | 1篇 |
无线电 | 18918篇 |
一般工业技术 | 27142篇 |
冶金工业 | 8274篇 |
原子能技术 | 880篇 |
自动化技术 | 31582篇 |
出版年
2023年 | 531篇 |
2022年 | 833篇 |
2021年 | 1403篇 |
2020年 | 993篇 |
2019年 | 1012篇 |
2018年 | 15408篇 |
2017年 | 14320篇 |
2016年 | 11305篇 |
2015年 | 1889篇 |
2014年 | 2244篇 |
2013年 | 3656篇 |
2012年 | 6173篇 |
2011年 | 12866篇 |
2010年 | 10848篇 |
2009年 | 8484篇 |
2008年 | 9396篇 |
2007年 | 9943篇 |
2006年 | 2346篇 |
2005年 | 3074篇 |
2004年 | 2927篇 |
2003年 | 2811篇 |
2002年 | 2156篇 |
2001年 | 1382篇 |
2000年 | 1375篇 |
1999年 | 1234篇 |
1998年 | 2242篇 |
1997年 | 1462篇 |
1996年 | 1245篇 |
1995年 | 969篇 |
1994年 | 735篇 |
1993年 | 691篇 |
1992年 | 501篇 |
1991年 | 516篇 |
1990年 | 417篇 |
1989年 | 404篇 |
1988年 | 330篇 |
1987年 | 275篇 |
1986年 | 254篇 |
1985年 | 231篇 |
1984年 | 199篇 |
1983年 | 151篇 |
1982年 | 152篇 |
1981年 | 130篇 |
1980年 | 129篇 |
1979年 | 102篇 |
1978年 | 94篇 |
1977年 | 123篇 |
1976年 | 158篇 |
1975年 | 80篇 |
1974年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Somsak Vanit-Anunchai Jonathan Billington Guy Edward Gallasch 《International Journal on Software Tools for Technology Transfer (STTT)》2008,10(1):29-56
State space explosion is a key problem in the analysis of finite state systems. The sweep-line method is a state exploration
method which uses a notion of progress to allow states to be deleted from memory when they are no longer required. This reduces
the peak number of states that need to be stored, while still exploring the full state space. The technique shows promise
but has never achieved reductions greater than about a factor of 10 in the number of states stored in memory for industrially
relevant examples. This paper discusses sweep-line analysis of the connection management procedures of a new Internet standard,
the Datagram Congestion Control Protocol (DCCP). As the intuitive approaches to sweep-line analysis are not effective, we
introduce new variables to track progress. This creates further state explosion. However, when used with the sweep-line, the
peak number of states is reduced by over two orders of magnitude compared with the original. Importantly, this allows DCCP
to be analysed for larger parameter values.
Somsak Vanit-Anunchai was partially supported by an Australian Research Council Discovery Grant (DP0559927) and Suranaree
University of Technology.
Guy Edward Gallasch was supported by an Australian Research Council Discovery Grant (DP0559927). 相似文献
53.
Takeshi Shiofuku Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2008,13(1):290-293
This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used
in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored
regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the
finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which
makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time
and promising to be merged into other application systems.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
54.
55.
Colour is the most widely used attribute in image retrieval and object recognition. A technique known as histogram intersection has been widely studied and is considered to be effective for color‐image indexing. The key issue of this algorithm is the selection of an appropriate color space and optimal quantization of the selected color space. The goal of this article is to measure the model performance in predicting human judgment in similarity measurement for various images, to explore the capability of the model with a wide set of color spaces, and to find the optimal quantization of the selected color spaces. Six color spaces and twelve quantization levels are involved in evaluating the performance of histogram intersection. The categorical judgment and rank order experiments were conducted to measure image similarity. The CIELAB color space was found to perform at least as good as or better than the other color spaces tested, and the ability to predict image similarity increased with the number of bins used in the histograms, for up to 512 bins (8 per channel). With more than 512 bins, further improvement was negligible for the image datasets used in this study. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 265–274, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20122 相似文献
56.
The biological decolorization of two industrial, spent textile reactive dyebaths was investigated using a suspended-growth, halophilic mixed culture fed with glucose. Dyebath I contained mainly Reactive Blue 19 (RB19), an anthraquinone dye, whereas dyebath II contained mainly Reactive Blue 21 (RB21), a phthalocyanine dye. Batch assays under anaerobic conditions with the two neutralized dyebaths resulted in 87 and 37% extent of decolorization for dyebaths I and II, respectively. The rate of glucose utilization and the extent of acetate production were impacted in the presence of each dyebath as compared to the control culture. However, dyebath decolorization occurred despite moderate culture inhibition. Reuse of a biologically renovated RB19-containing dyebath in the dyeing process resulted in reproducible but not identical cotton fabric shades as compared to a standard dyeing (i.e., control) using fresh water. This difference is attributed to a variable degree of RB19 aggregation during the dyeing process and is not related to the efficiency of the biodecolorization process. Further improvement of the redyeing efficiency will lead to the development of an in-plant, closed-loop decolorization system resulting in significant water conservation and minimization of textile pollutants such as salt and dyes. 相似文献
57.
58.
59.
60.