全文获取类型
收费全文 | 45074篇 |
免费 | 2712篇 |
国内免费 | 44篇 |
专业分类
电工技术 | 391篇 |
综合类 | 27篇 |
化学工业 | 9136篇 |
金属工艺 | 891篇 |
机械仪表 | 886篇 |
建筑科学 | 1495篇 |
矿业工程 | 107篇 |
能源动力 | 1084篇 |
轻工业 | 7243篇 |
水利工程 | 419篇 |
石油天然气 | 165篇 |
武器工业 | 5篇 |
无线电 | 2000篇 |
一般工业技术 | 7505篇 |
冶金工业 | 9514篇 |
原子能技术 | 220篇 |
自动化技术 | 6742篇 |
出版年
2023年 | 368篇 |
2022年 | 383篇 |
2021年 | 1202篇 |
2020年 | 900篇 |
2019年 | 1084篇 |
2018年 | 1776篇 |
2017年 | 1707篇 |
2016年 | 1822篇 |
2015年 | 1354篇 |
2014年 | 1687篇 |
2013年 | 3316篇 |
2012年 | 2624篇 |
2011年 | 2656篇 |
2010年 | 2084篇 |
2009年 | 1941篇 |
2008年 | 1906篇 |
2007年 | 1770篇 |
2006年 | 1284篇 |
2005年 | 1107篇 |
2004年 | 986篇 |
2003年 | 861篇 |
2002年 | 858篇 |
2001年 | 626篇 |
2000年 | 559篇 |
1999年 | 585篇 |
1998年 | 2840篇 |
1997年 | 1946篇 |
1996年 | 1248篇 |
1995年 | 777篇 |
1994年 | 613篇 |
1993年 | 688篇 |
1992年 | 275篇 |
1991年 | 273篇 |
1990年 | 214篇 |
1989年 | 220篇 |
1988年 | 199篇 |
1987年 | 186篇 |
1986年 | 174篇 |
1985年 | 197篇 |
1984年 | 168篇 |
1983年 | 134篇 |
1982年 | 168篇 |
1981年 | 187篇 |
1980年 | 190篇 |
1979年 | 97篇 |
1978年 | 97篇 |
1977年 | 308篇 |
1976年 | 668篇 |
1975年 | 70篇 |
1973年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Sánchez-Vásquez J. D. Portillo-Rodríguez B. Tovar-Martínez E. Reyes-Reyes M. López-Sandoval R. 《Journal of Materials Science: Materials in Electronics》2022,33(18):14910-14926
Journal of Materials Science: Materials in Electronics - Non-volatile organic memory devices were fabricated using polystyrene sulfonate (PSS)?+?nitrogen-doped multi-walled carbon... 相似文献
2.
3.
Chanh Constance Gourment Anaïs Petit Betrand Gourgues-Lorenzon Anne-Françoise 《International Journal of Fracture》2022,235(2):215-230
International Journal of Fracture - The development of high-performance automotive steels involves increasingly complex chemistries and heat treating sequences, to produce stronger and lighter... 相似文献
4.
5.
6.
7.
Silvina Patricia Meriles Roxana Piloni Georgina Vanesa Cáceres María Cecilia Penci María Andrea Marín Pablo Ribotta Marcela Lilian Martínez 《International Journal of Food Science & Technology》2022,57(8):4689-4696
The study was conducted to evaluate the effect of non-traditional and highly available and nutrient-dense ingredients in the production of value-added crackers. The crackers were prepared by combining partially defatted chia flour, wheat germ, quinoa, and oat. The antioxidant activity and the polyphenol content were 7.0–8.4 times higher in crackers produced with non-traditional ingredients compared to the control snack. The hydroperoxide value indicated a low oxidative deterioration of the oil. The sample with 10% of partially defatted chia flour was selected for shelf-life test under storage conditions and sensory evaluation. Modified atmosphere exerted a protective effect on the lipid stability regardless of the incorporation of BHT to the formulation. All the evaluated attributes scored highly during consumer acceptance. The formulated cracker presented a relevant content of protein, dietary fibre and omega-3 and -6 fatty acids. Based on these results, the crackers containing non-traditional ingredients resulted in a product with a good potential for both consumer acceptance and outstanding nutritional benefits. 相似文献
8.
Policicchio Alfonso Putz Ana-Maria Conte Giuseppe Stelitano Sara Bonaventura Carlo Poselle Ianăşi Cătălin Almásy László Wacha András Horváth Zsolt Endre Agostino Raffaele G. 《Journal of Porous Materials》2021,28(4):1049-1058
Journal of Porous Materials - The present study reports a systematic analysis of morphology and hydrogen sorption capacity of mesoporous organic-inorganic silica prepared by varying the silica... 相似文献
9.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability. 相似文献
10.
This study evaluates environmental aggressiveness and atmospheric galvanic corrosivity categories in Chile (Classification of Industrial and Marine ATmospheres test) by installing bolts in electrical transmission towers in the Valparaiso region across four exposure sites: Playa Ancha, San Sebastián, Las Vegas, and San Felipe. Classifications of marine corrosion index (MCI), industrial corrosion index (ICI), and atmospheric corrosion index (ACI) used different galvanic couples: aluminum/steel for MCI, aluminum/copper for ICI, and aluminum/polyethylene for ACI. Corrosion indices varied by season (summer, autumn, winter, and spring), for which couples were exchanged every 3 months. Intraseason variation depended mainly on the meteorochemical variables of the zone, the Cl−/SO2 ratio, and the presence of general and pitting corrosion in the aluminum. The results indicate that, regardless of environmental condition, the aluminum in Al/steel (MCI) and Al/copper (ICI) couples presented a higher corrosion rate than when not forming a galvanic couple (ACI). Moreover, under higher environmental chloride, these differences increase. The Playa Ancha station presented the highest ACI. 相似文献