全文获取类型
收费全文 | 358034篇 |
免费 | 11627篇 |
国内免费 | 5038篇 |
专业分类
电工技术 | 10732篇 |
技术理论 | 6篇 |
综合类 | 6557篇 |
化学工业 | 53663篇 |
金属工艺 | 16316篇 |
机械仪表 | 15408篇 |
建筑科学 | 14133篇 |
矿业工程 | 4477篇 |
能源动力 | 9267篇 |
轻工业 | 29079篇 |
水利工程 | 4211篇 |
石油天然气 | 11209篇 |
武器工业 | 873篇 |
无线电 | 45211篇 |
一般工业技术 | 61258篇 |
冶金工业 | 51331篇 |
原子能技术 | 6421篇 |
自动化技术 | 34547篇 |
出版年
2022年 | 4339篇 |
2021年 | 6261篇 |
2020年 | 4822篇 |
2019年 | 4701篇 |
2018年 | 6353篇 |
2017年 | 6788篇 |
2016年 | 6745篇 |
2015年 | 6403篇 |
2014年 | 8914篇 |
2013年 | 17047篇 |
2012年 | 12814篇 |
2011年 | 15528篇 |
2010年 | 12708篇 |
2009年 | 13306篇 |
2008年 | 13970篇 |
2007年 | 13642篇 |
2006年 | 13140篇 |
2005年 | 11803篇 |
2004年 | 9824篇 |
2003年 | 9527篇 |
2002年 | 8984篇 |
2001年 | 8860篇 |
2000年 | 8475篇 |
1999年 | 8867篇 |
1998年 | 16288篇 |
1997年 | 11968篇 |
1996年 | 9790篇 |
1995年 | 7799篇 |
1994年 | 6850篇 |
1993年 | 6309篇 |
1992年 | 5189篇 |
1991年 | 4644篇 |
1990年 | 4396篇 |
1989年 | 4075篇 |
1988年 | 3849篇 |
1987年 | 3319篇 |
1986年 | 3187篇 |
1985年 | 3680篇 |
1984年 | 3435篇 |
1983年 | 3073篇 |
1982年 | 2891篇 |
1981年 | 2979篇 |
1980年 | 2785篇 |
1979年 | 2664篇 |
1978年 | 2500篇 |
1977年 | 2945篇 |
1976年 | 3554篇 |
1975年 | 2316篇 |
1974年 | 2312篇 |
1973年 | 2318篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Klimis?S.?NtalianisEmail author Anastasios?D.?Doulamis Nikolaos?D.?Doulamis Nikos?E.?Mastorakis Athanasios?S.?Drigas 《Journal of Signal Processing Systems》2015,80(2):153-161
In this paper, we present a novel memory access reduction scheme (MARS) for two-dimension fast cosine transform (2-D FCT). It targets programmable DSPs with high memory-access latency. It reduces the number of memory accesses by: 1) reducing the number of weighting factors and 2) combining butterflies in vector-radix 2-D FCT pruning diagram from two stages to one stage with an efficient structure. Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation. Experimental results validate the benefits of the proposed method with reduced memory access, less clock cycle and fewer memory space compared with the conventional implementation. 相似文献
2.
With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized in the decoding layer, which makes the triples and generated questions more relevant. Finally, the experimental results on SimpleQuestions demonstrate the effectiveness of the proposed approach. 相似文献
3.
Anaerobic co-digestion of food waste and FOG with sewage sludge – realising its potential in Ireland
Olumide Wesley Awe Yaqian Zhao Ange Nzihou Doan Pham Minh Nathalie Lyczko 《The International journal of environmental studies》2018,75(3):496-517
The severe environmental pollution in many countries is caused by indiscriminate discharge of large quantities of food waste (FW), fat oil and grease (FOG) and sewage sludge (SS) to the environment. There are many possible treatment routes, but anaerobic digestion (AD) is now well accepted for treating several kinds of organic wastes. But AD of FW alone presents some operational challenges because of substrates and variability. Anaerobic co-digestion of two or more substrates is better than single substrate digestion. This can use a plant’s unused capacity, in line with the trend to renewable energy. Co-digestion technology, although well established in many European countries, is still in its infancy in Ireland. There are problems with different regulatory arrangements. They should be resolved. The paper reviews anaerobic co-digestion technology is reviewed, with special focus on possible application in Ireland. 相似文献
4.
Christoph Gottschalk Aiko Huckauf Arne Dübecke Florian Kaltner Matthias Zimmermann Ines Rahaus 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(7):1366-1383
The contamination of honey with hepatotoxic pyrrolizidine alkaloids (PAs) is a well-known hazard for food safety. While management strategies and controls of the honey industry aim to reduce the PA levels, uncertainties remain with regard to the safety of regionally produced and marketed honey. In addition, a previous study showed large differences of results obtained after various periods of storage and apparent differences between the analytical results of different laboratories. Therefore, this study aimed at examining these uncertainties by monitoring the impact of storage on the PA and PA N-oxide (PANO) content of two freshly harvested honeys and on possible demixing effects caused by pollen settling. Additionally, three analytical approaches – target analysis with matrix-matched calibration or standard addition and a sum parameter method – were applied for a comparative analysis of 20 honeys harvested in summer 2016. All samples originated from Schleswig-Holstein in Northern Germany where the PA plant Jacobaea vulgaris is currently observed on a massive scale. The results of the time series analyses showed that PANO levels markedly decreased within a few weeks and practically reached the LOD 16 weeks after harvest. Tertiary PAs, by contrast, remained stable and did not increase as a consequence of PANO decrease. The experiments on a putative demixing, which may result in a heterogeneous distribution of PAs/PANOs, revealed that there was no such effect during storage of up to 12 weeks. A comparison of the PA/PANO levels obtained by different analytical approaches showed that in some cases the sum parameter method yielded much higher levels than the target approaches, whereas in other cases, the target analysis with standard addition found higher levels than the other two methods. In summary, the results of this study highlight uncertainties regarding the validity and comparability of analytical results and consequently regarding health risk assessment. 相似文献
5.
6.
7.
8.
Pasquale Stano Tereza Pereira de Souza Paolo Carrara Emiliano Altamura Erica D’Aguanno Margherita Caputo 《先进材料力学与结构力学》2015,22(9):748-759
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations. 相似文献
9.
10.
Effect of gums on viability and β‐galactosidase activity of Lactobacillus spp. in milk drink during refrigerated storage 下载免费PDF全文
Bernice D. Karlton‐Senaye Reza Tahergorabi Valerie L. Giddings Salam A. Ibrahim 《International Journal of Food Science & Technology》2015,50(1):32-40
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus. 相似文献