全文获取类型
收费全文 | 1085篇 |
免费 | 121篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
综合类 | 1篇 |
化学工业 | 293篇 |
金属工艺 | 10篇 |
机械仪表 | 20篇 |
建筑科学 | 47篇 |
矿业工程 | 1篇 |
能源动力 | 46篇 |
轻工业 | 258篇 |
水利工程 | 11篇 |
石油天然气 | 9篇 |
无线电 | 81篇 |
一般工业技术 | 164篇 |
冶金工业 | 92篇 |
原子能技术 | 9篇 |
自动化技术 | 153篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 33篇 |
2021年 | 51篇 |
2020年 | 25篇 |
2019年 | 43篇 |
2018年 | 52篇 |
2017年 | 53篇 |
2016年 | 55篇 |
2015年 | 39篇 |
2014年 | 62篇 |
2013年 | 80篇 |
2012年 | 73篇 |
2011年 | 87篇 |
2010年 | 67篇 |
2009年 | 55篇 |
2008年 | 61篇 |
2007年 | 50篇 |
2006年 | 37篇 |
2005年 | 35篇 |
2004年 | 30篇 |
2003年 | 18篇 |
2002年 | 21篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 10篇 |
1998年 | 32篇 |
1997年 | 28篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有1207条查询结果,搜索用时 15 毫秒
41.
42.
María Dolores López‐Ramírez Ulises Miguel García‐Ventura Fabricio Omar Barroso‐Muñoz Juan Gabriel Segovia‐Hernández Salvador Hernández 《化学工程与技术》2016,39(2):271-275
The esterification of oleic acid and methanol using sulfuric acid as a homogeneous catalyst is studied in reactive‐separation systems. The conversion of the free fatty acid was investigated in two different experiments with the molar ratio of methanol/oleic acid, amount of catalyst, temperature, and reaction time as variables. The conversion of the free fatty acid was found to depend strongly on the molar ratio of methanol/oleic acid. The reaction time had a direct effect on the conversion of the free fatty acid, and this conversion decreased with higher temperature. These results were valuable for a preliminary study on biodiesel production, using an acid homogeneous catalyst in a reactive dividing‐wall distillation column. 相似文献
43.
44.
Valdivino Alexandre de Santiago Júnior Nandamudi Lankalapalli Vijaykumar 《Software Quality Journal》2012,20(1):77-143
Natural Language (NL) deliverables suffer from ambiguity, poor understandability, incompleteness, and inconsistency. Howewer,
NL is straightforward and stakeholders are familiar with it to produce their software requirements documents. This paper presents
a methodology, SOLIMVA, which aims at model-based test case generation considering NL requirements deliverables. The methodology
is supported by a tool that makes it possible to automatically translate NL requirements into Statechart models. Once the
Statecharts are derived, another tool, GTSC, is used to generate the test cases. SOLIMVA uses combinatorial designs to identify
scenarios for system and acceptance testing, and it requires that a test designer defines the application domain by means
of a dictionary. Within the dictionary there is a Semantic Translation Model in which, among other features, a word sense disambiguation method helps in the translation process. Using as a case study
a space application software product, we compared SOLIMVA with a previous manual approach developed by an expert under two
aspects: test objectives coverage and characteristics of the Executable Test Cases. In the first aspect, the SOLIMVA methodology
not only covered the test objectives associated to the expert’s scenarios but also proposed a better strategy with test objectives
clearly separated according to the directives of combinatorial designs. The Executable Test Cases derived in accordance with
the SOLIMVA methodology not only possessed similar characteristics with the expert’s Executable Test Cases but also predicted
behaviors that did not exist in the expert’s strategy. The key benefits from applying the SOLIMVA methodology/tool within
a Verification and Validation process are the ease of use and, at the same time, the support of a formal method consequently
leading to a potential acceptance of the methodology in complex software projects. 相似文献
45.
46.
47.
48.
A first approach towards the development of geographical origin tracing models for North Moroccan olive oils based on triacylglycerols profiles
下载免费PDF全文
![点击此处可从《European Journal of Lipid Science and Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
49.
The controlled synthesis of narrowly distributed low molecular weight polymers with functionalization possibilities is of great industrial interests. Although living polymerization allows for control over polymer architecture, the production of low molecular weight polymers with low polydispersities via living polymerization systems is challenged by the use of large amounts of catalysts and broadening in molecular weight distribution. This review addresses the synthesis of narrowly distributed, functional, low molecular weight polyethylene and polyethylene mimics. The review is structured for quick identification of relevant systems for the production of specific polymer architectures with specific cost, efficiency, and safety concerns. 相似文献
50.
Gabriela Loscalzo Julia Scheel Jos Santiago Ibaez-Cabellos Eva García-Lopez Shailendra Gupta Jos Luis García-Gimenez Salvador Mena-Moll Alfredo Perales-Marín Jos Morales-Rosell 《International journal of molecular sciences》2022,23(1)
In a prospective study, 48 fetuses were evaluated with Doppler ultrasound after 34 weeks and classified, according to the cerebroplacental ratio (CPR) and estimated fetal weight (EFW), into fetuses with normal growth and fetuses with late-onset fetal growth restriction (LO-FGR). Overexpression of miRNAs from neonatal cord blood belonging to LO-FGR fetuses, was validated by real-time PCR. In addition, functional characterization of overexpressed miRNAs was performed by analyzing overrepresented pathways, gene ontologies, and prioritization of synergistically working miRNAs. Three miRNAs: miR-25-3p, miR-185-5p and miR-132-3p, were significantly overexpressed in cord blood of LO-FGR fetuses. Pathway and gene ontology analysis revealed over-representation of certain molecular pathways associated with cardiac development and neuron death. In addition, prioritization of synergistically working miRNAs highlighted the importance of miR-185-5p and miR-25-3p in cholesterol efflux and starvation responses associated with LO-FGR phenotypes. Evaluation of miR-25-3p; miR-132-3p and miR-185-5p might serve as molecular biomarkers for the diagnosis and management of LO-FGR; improving the understanding of its influence on adult disease. 相似文献