全文获取类型
收费全文 | 23422篇 |
免费 | 2126篇 |
国内免费 | 1131篇 |
专业分类
电工技术 | 1662篇 |
技术理论 | 6篇 |
综合类 | 3694篇 |
化学工业 | 1777篇 |
金属工艺 | 525篇 |
机械仪表 | 842篇 |
建筑科学 | 3550篇 |
矿业工程 | 834篇 |
能源动力 | 807篇 |
轻工业 | 3038篇 |
水利工程 | 638篇 |
石油天然气 | 798篇 |
武器工业 | 147篇 |
无线电 | 1461篇 |
一般工业技术 | 1678篇 |
冶金工业 | 894篇 |
原子能技术 | 255篇 |
自动化技术 | 4073篇 |
出版年
2024年 | 116篇 |
2023年 | 285篇 |
2022年 | 539篇 |
2021年 | 641篇 |
2020年 | 761篇 |
2019年 | 584篇 |
2018年 | 580篇 |
2017年 | 651篇 |
2016年 | 798篇 |
2015年 | 922篇 |
2014年 | 1485篇 |
2013年 | 1461篇 |
2012年 | 1769篇 |
2011年 | 1772篇 |
2010年 | 1395篇 |
2009年 | 1364篇 |
2008年 | 1358篇 |
2007年 | 1606篇 |
2006年 | 1472篇 |
2005年 | 1181篇 |
2004年 | 957篇 |
2003年 | 839篇 |
2002年 | 715篇 |
2001年 | 516篇 |
2000年 | 497篇 |
1999年 | 386篇 |
1998年 | 352篇 |
1997年 | 282篇 |
1996年 | 240篇 |
1995年 | 209篇 |
1994年 | 197篇 |
1993年 | 120篇 |
1992年 | 145篇 |
1991年 | 104篇 |
1990年 | 73篇 |
1989年 | 75篇 |
1988年 | 49篇 |
1987年 | 36篇 |
1986年 | 29篇 |
1985年 | 23篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1964年 | 5篇 |
1960年 | 5篇 |
1955年 | 7篇 |
1954年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(2):1306-1318
The effective and efficient utilization of low-calorific value (LCV) gases has gained increasing attention in scientific research and industrial fields. In this study, the combustion characteristics of three LCV gases in practical devices are analyzed by using a nonadiabatic perfectly stirred reactor model. The complete steady-state solution in the temperature-residence time parameter space is obtained with arc-length continuation. The stable operation region is quantified by the eigenvalue analysis. The transition of solution curves is quantified with heat loss coefficient. Five key system parameters are systematically investigated on their effects on stability limits. With the combustion performance being quantified by a combustion state index, a combustion state regulation method is proposed to find the optimal regulation path of system parameters. Active subspace method is further applied to shorten the regulation step by identifying the active direction. The proposed method and findings are useful for optimal regulation of burning LCV gases in industrial burners. 相似文献
2.
Elli Ntakou Ralph Masiello Farnaz Farzan Shay Bahramirad Aleksi Paaso M.A. Nayeem Maigha Maigha Daniel Kushner 《The Electricity Journal》2019,32(4):45-49
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal. 相似文献
3.
现行的政府单一主导、政府与开发
商合作的社区更新模式与业主的自主更新需
求产生了矛盾。针对现有研究对社区更新的
系统性缺乏关注的问题,本文从整体视角出
发,通过构建“参与主体—程序设计—法规
政策—资金调配”四维框架,分析现行社区
更新模式与业主自主更新需求产生冲突的内
在机制。在优化现有模式的基础上,提出三
种适应业主自主更新需求的理论模式。桂华
邨业主自主更新失败的实践案例证明了本文
所提出的四维框架的重要性。最后,从政府
视角对我国社区更新机制提出优化建议。 相似文献
4.
In recent years, artificial intelligence (AI) is being increasingly utilised in disaster management activities. The public is engaged with AI in various ways in these activities. For instance, crowdsourcing applications developed for disaster management to handle the tasks of collecting data through social media platforms, and increasing disaster awareness through serious gaming applications. Nonetheless, there are limited empirical investigations and understanding on public perceptions concerning AI for disaster management. Bridging this knowledge gap is the justification for this paper. The methodological approach adopted involved: Initially, collecting data through an online survey from residents (n = 605) of three major Australian cities; Then, analysis of the data using statistical modelling. The analysis results revealed that: (a) Younger generations have a greater appreciation of opportunities created by AI-driven applications for disaster management; (b) People with tertiary education have a greater understanding of the benefits of AI in managing the pre- and post-disaster phases, and; (c) Public sector administrative and safety workers, who play a vital role in managing disasters, place a greater value on the contributions by AI in disaster management. The study advocates relevant authorities to consider public perceptions in their efforts in integrating AI in disaster management. 相似文献
5.
6.
7.
Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wen Li Xiaobei Li Yan Yang Feng Zhou Yanfang Liu Shuai Zhou Hailong Yu 《International Journal of Food Science & Technology》2015,50(11):2360-2366
Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels. 相似文献
8.
This paper explores the process of public sector reform in Greece through the lens of privatisation. It is suggested that the transformation of the domestic post-war interventionist state into the current market-oriented paradigm has been disrupted and dependent on changing reform rationales. Along with the effect of historical dynamics on the direction and scale of change, the explanatory power of external determinants of reform is stressed. Findings reflect a direct linkage between the intensity of external pressure and the pace of reforms. The sustainability of gradual privatisation reforms seems more certain than the outcomes of fast-track privatisations under policy conditionality. 相似文献
9.
The Indian telephony industry is a diverse platform for product and service in customer value perception. The present study organizes and synthesizes the varied research streams for developing a customer value delight (CVD) framework for marketing decisions like segmentation and targeting. The conceptual framework is developed by using ten-value predictor variables and customer delight through divergent viewpoints identified from previous studies. The significance of the segregation proposition is tested through discriminant analysis in three different dimension runs i.e. delight, gender, and marital category. The scholarship behind the study provides insight into an imperative issue of segregating customer delight by perceived value predictors in categories. The perceptual mapping and vector magnitude analysis of value predictors were performed to club customers in two categories of Mid-Town (low/moderate delight) and Extremes (high delight). The analysis rigorously supports the discriminating power of perceived price, perceived benefit, and self-congruity. The salience of study unlocks psychographic and demographic perceptual maps of customer delight with its perceived value predictors for strategic and tactful planning in the mobile industry. 相似文献
10.
Maria A. Ospina Monica Pizarro Thierry Tran Julien Ricci John Belalcazar Jorge L. Luna Luis F. Londoño Sandra Salazar Hernan Ceballos Dominique Dufour Luis A. Becerra Lopez-Lavalle 《International Journal of Food Science & Technology》2021,56(3):1343-1353
The objective of this study was to characterise the nutritional potential of leaves and identify a diversity centre with low cyanide and high nutrient content among 178 Latin American cassava genotypes. This field-based collection represents the seven diversity centres, held at The International Center for Tropical Agriculture (CIAT Palmira, Colombia) by the Cassava Program. The cyanide, all-trans-β-carotene and lutein concentrations in cassava leaves ranged from 346 to 7484 ppm dry basis (db), from 174–547 μg g−1 db and 15–181 μg g−1 db, respectively. Cassava leaves also showed significant levels of essential amino acids leucine, lysine, phenylalanine, valine and threonine, and average total protein content of 26.24 g 100 g−1 db. Among seven diversity centres, South American rainforest group showed low cyanide and high carotene content in leaves. In addition, VEN77 and PAN51 genotypes stood out for having low cyanide in leaves and roots and high carotene in leaves. This genetic diversity can be used to select high potential progenitors for breeding purposes. 相似文献