全文获取类型
收费全文 | 40101篇 |
免费 | 1962篇 |
国内免费 | 39篇 |
专业分类
电工技术 | 423篇 |
综合类 | 61篇 |
化学工业 | 8428篇 |
金属工艺 | 851篇 |
机械仪表 | 751篇 |
建筑科学 | 2221篇 |
矿业工程 | 89篇 |
能源动力 | 1114篇 |
轻工业 | 3583篇 |
水利工程 | 353篇 |
石油天然气 | 128篇 |
武器工业 | 5篇 |
无线电 | 2745篇 |
一般工业技术 | 7563篇 |
冶金工业 | 7099篇 |
原子能技术 | 313篇 |
自动化技术 | 6375篇 |
出版年
2023年 | 307篇 |
2022年 | 186篇 |
2021年 | 802篇 |
2020年 | 632篇 |
2019年 | 725篇 |
2018年 | 945篇 |
2017年 | 900篇 |
2016年 | 1168篇 |
2015年 | 1003篇 |
2014年 | 1368篇 |
2013年 | 2383篇 |
2012年 | 2035篇 |
2011年 | 2587篇 |
2010年 | 1872篇 |
2009年 | 1836篇 |
2008年 | 2103篇 |
2007年 | 1937篇 |
2006年 | 1739篇 |
2005年 | 1417篇 |
2004年 | 1296篇 |
2003年 | 1127篇 |
2002年 | 1041篇 |
2001年 | 635篇 |
2000年 | 612篇 |
1999年 | 622篇 |
1998年 | 940篇 |
1997年 | 817篇 |
1996年 | 698篇 |
1995年 | 601篇 |
1994年 | 543篇 |
1993年 | 570篇 |
1992年 | 456篇 |
1991年 | 297篇 |
1990年 | 399篇 |
1989年 | 390篇 |
1988年 | 324篇 |
1987年 | 358篇 |
1986年 | 356篇 |
1985年 | 374篇 |
1984年 | 324篇 |
1983年 | 326篇 |
1982年 | 317篇 |
1981年 | 281篇 |
1980年 | 243篇 |
1979年 | 251篇 |
1978年 | 224篇 |
1977年 | 274篇 |
1976年 | 310篇 |
1975年 | 189篇 |
1974年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
1.
Journal of Low Temperature Physics - This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its... 相似文献
2.
Brennan Michael C. Howard Marylesa Marzouk Youssef Dresselhaus-Marais Leora E. 《Journal of Materials Science》2022,57(31):14890-14904
Journal of Materials Science - We develop several inference methods to estimate the position of dislocations from images generated using dark-field X-ray microscopy (DFXM)—achieving... 相似文献
3.
Cognitive and metabolic workload assessment techniques: A review in automotive manufacturing context
Ergonomics assessment in the automotive industry has, to date, focused mainly on physical ergonomics, for example, manual handling and posture. However, workload and, in particular, metabolic and cognitive workload, contributes to worker efficiency but has not received sufficient attention to yield practical guidance for industry. Successful workload assessment requires in-depth understanding of the context in which it will be conducted and of the various assessment techniques which will be applied, with consideration given to factors such as feasibility, resources, and skill of the assessor. These requirements are met with challenges within large and complex organizations and are often dealt with in a piecemeal and isolated matter (i.e., reactive workload assessment). The present paper explores these challenges within the automotive manufacturing industry and aims to develop a decision matrix to guide effective selection of workload assessment techniques focused on metabolic and cognitive demands. It also presents the requirements for time, equipment, and knowledge to implement these techniques as part of a participatory ergonomics approach. Early findings suggest that most assessment techniques reviewed require further development, for example, to establish the acceptance criteria for the specific workload scenario. However, five methods (Garg, Borg RPE, IPAQ, SWAT, and NASA-TLX) are ready to use in certain applications. Ultimately, the findings suggest that it is possible to implement a participatory workload evaluation program within large and complex manufacturing plants. 相似文献
4.
Stumpo Vittorio Sebök Martina van Niftrik Christiaan Hendrik Bas Seystahl Katharina Hainc Nicolin Kulcsar Zsolt Weller Michael Regli Luca Fierstra Jorn 《Magma (New York, N.Y.)》2022,35(1):29-44
Magnetic Resonance Materials in Physics, Biology and Medicine - Innovative physiologic MRI development focuses on depiction of heterogenous vascular and metabolic features in glioblastoma. For this... 相似文献
5.
6.
Thomsen Maria Carmignani Luca Rodriguez Andy Scudiere Charles Liveretou Christina Fernandez-Pello Carlos Gollner Michael Olson Sandra Ferkul Paul 《Fire Technology》2022,58(4):2229-2250
Fire Technology - There are multiple situations in which fires may occur at environmental conditions that are different than standard atmospheric conditions. Changes in ambient pressure, oxygen... 相似文献
7.
Leonie Reinders Stephanie Pfeifer Sarah Kröner Heiko Stolpmann Achim Renfftlen L. Charlyn Greiler Bernd Clauß Michael R. Buchmeiser 《Journal of the European Ceramic Society》2021,41(6):3570-3580
Polycrystalline mullite fibers and novel zirconia-toughened mullite (ZTM) fibers with average diameters between 9.7 and 10.3 μm containing 3, 7 and 15 wt.-% tetragonal ZrO2 (ZTM3, ZTM7, ZTM15) in the final ceramic were prepared via dry spinning followed by continuous calcination and sintering in air. A shift in the formation of transient alumina phases and tetragonal ZrO2 to higher temperatures with increasing amounts of ZrO2 was observed. Concomitantly, the mullite formation temperature was lowered to 1229 °C for ZTM15 fibers. X-ray diffraction revealed formation of the desired tetragonal crystal structure of ZrO2 directly from the amorphous precursor. Room temperature Weibull strengths of 1320, 1390 and 1740 MPa and Weibull moduli of 9.5, 7.1 and 9.0 were determined for mullite, ZTM3 and ZTM15 fibers, respectively. Average Young’s moduli ranged from 190 to 220 GPa. SEM images revealed crack-free fiber surfaces and compact microstructures independent of the amount of ZrO2. 相似文献
8.
Marcus Reppich Zdeněk Jegla Jakob Grondinger Yaovi Ouézou Azouma Vojtěch Turek 《化学,工程师,技术》2021,93(10):1581-1589
This study investigates the behavior of fruit and vegetable samples during drying. The experimental data are fitted to several different thin-layer drying models. Regression analysis is used to determine model parameters, while statistical indicators serve to evaluate the goodness of fit. The power function model gives the best fit for all examined samples. Based on this model, different drying and heat storage technologies can be combined to ensure that the required residual moisture content of an agricultural product is reached. It is demonstrated on the case of a specific Togolese processing plant that under favorable conditions, fossil fuel consumption can be decreased by 33 %. 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.
Felix Kexel Alexandra von Kameke Janina Tenhaus Marko Hoffmann Michael Schlüter 《化学,工程师,技术》2021,93(5):830-837
A consecutive competitive gas-liquid reaction is investigated using a Taylor bubble setup regarding the influence of fluid mixing in the bubble wake on yield and selectivity. The concentration fields behind a Taylor bubble are visualized and measured quantitatively with a novel time-resolved absorption imaging technique based on Beer Lamberts law and an integral selectivity is derived. In addition, the calculation of the local selectivity, often used in numerical approaches, is discussed and the existing experimental limits for its derivation are pointed out. Finally, an increase in selectivity of a competitive consecutive reaction for enhanced mixing is experimentally confirmed. 相似文献