全文获取类型
收费全文 | 959篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 3篇 |
化学工业 | 252篇 |
金属工艺 | 29篇 |
机械仪表 | 15篇 |
建筑科学 | 32篇 |
能源动力 | 33篇 |
轻工业 | 72篇 |
水利工程 | 5篇 |
石油天然气 | 1篇 |
无线电 | 133篇 |
一般工业技术 | 182篇 |
冶金工业 | 34篇 |
原子能技术 | 16篇 |
自动化技术 | 142篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 27篇 |
2013年 | 55篇 |
2012年 | 47篇 |
2011年 | 52篇 |
2010年 | 50篇 |
2009年 | 53篇 |
2008年 | 50篇 |
2007年 | 43篇 |
2006年 | 45篇 |
2005年 | 43篇 |
2004年 | 25篇 |
2003年 | 31篇 |
2002年 | 34篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 23篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1971年 | 5篇 |
排序方式: 共有962条查询结果,搜索用时 593 毫秒
951.
Real-time quantitative PCR assays were developed for the absolute quantification of lactic acid bacteria (LAB) (Streptococcus thermophilus, Lactobacillus delbrueckii, L. casei, L. paracasei, L. rhamnosus, L. acidophilus and L. johnsonii) in fermented milk products. The results of molecular quantification and classic bacterial enumeration did not differ significantly with respect to S. thermophilus and the species of the L. casei group which were detected in the six commercial fermented products tested, thus showing that DNA extraction was efficient and that genomic DNA solutions were free of PCR inhibitors. For L. delbrueckii, the results of bacterial enumeration were generally lower by a factor 10 to 100 than those of PCR quantification, suggesting a loss of viability during storage of the dairy products at 1-8 degrees C for most of the strains in this species. Real-time quantitative assays enabled identification of the species of lactic acid bacterial strains initially present in commercial fermented milk products and their accurate quantification with a detection threshold of 10(3) cells per ml of product. 相似文献
952.
Caroline Celle Céline Mayousse Eléonore Moreau Henda Basti Alexandre Carella Jean-Pierre Simonato 《Nano Research》2012,5(6):427-433
We demonstrate a new concept for the fabrication of flexible transparent thin film heaters based on silver nanowires. Thanks
to the intrinsic properties of random networks of metallic nanowires, it is possible to combine bendability, transparency
and high heating performances at low voltage, typically below 12 V which is of interest for many applications. This is currently
not possible with transparent conductive oxide technologies, and it compares well with similar devices fabricated with carbon
nanotubes or graphene. We present experiments on glass and poly(ethylene naphthalate) (PEN) substrates (with thicknesses of
125 μm and extremely thin 1.3 μm) with excellent heating performances. We point out that the amount of silver necessary to
realize the transparent heaters is very low and we also present preliminary results showing that this material can be efficiently
used to fabricate photochromic displays. To our knowledge, this is the first report of metallic nanowire-based transparent
thin film heaters. We think these results could be a useful approach for the engineering of highly flexible and transparent
heaters which are not attainable by existing processes.
相似文献
953.
Nadezhda Knauer Valeria Arkhipova Guanzhang Li Michael Hewera Ekaterina Pashkina Phuong-Hien Nguyen Maria Meschaninova Vladimir Kozlov Wei Zhang Roland S. Croner Anne-Marie Caminade Jean-Pierre Majoral Evgeny K. Apartsin Ulf D. Kahlert 《International journal of molecular sciences》2022,23(10)
Tumor cells with stem cell properties are considered to play major roles in promoting the development and malignant behavior of aggressive cancers. Therapeutic strategies that efficiently eradicate such tumor stem cells are of highest clinical need. Herein, we performed the validation of the polycationic phosphorus dendrimer-based approach for small interfering RNAs delivery in in vitro stem-like cells as models. As a therapeutic target, we chose Lyn, a member of the Src family kinases as an example of a prominent enzyme class widely discussed as a potent anti-cancer intervention point. Our selection is guided by our discovery that Lyn mRNA expression level in glioma, a class of brain tumors, possesses significant negative clinical predictive value, promoting its potential as a therapeutic target for future molecular-targeted treatments. We then showed that anti-Lyn siRNA, delivered into Lyn-expressing glioma cell model reduces the cell viability, a fact that was not observed in a cell model that lacks Lyn-expression. Furthermore, we have found that the dendrimer itself influences various parameters of the cells such as the expression of surface markers PD-L1, TIM-3 and CD47, targets for immune recognition and other biological processes suggested to be regulating glioblastoma cell invasion. Our findings prove the potential of dendrimer-based platforms for therapeutic applications, which might help to eradicate the population of cancer cells with augmented chemotherapy resistance. Moreover, the results further promote our functional stem cell technology as suitable component in early stage drug development. 相似文献
954.
芬顿试剂处理废水的研究与应用进展 总被引:16,自引:0,他引:16
介绍了介导高级氧化反应的芬顿试剂的机理研究进程,概述了芬顿试剂在处理氰化物、酚类、染料废水、染料中间体废水、农药废水、焦化废水、垃圾渗滤液中的应用研究进展,并说明了芬顿试剂单独或与其他废水处理技术联用的工业实例,认为芬顿试剂在实际的工业运用中,无论是作为中间处理手段提高废水的可生化性,还是作为最后步骤对废水进行深度处理,都有自身的优势。 相似文献
955.
This paper presents our experience of modeling land transportation domain in the formal framework of Event-B. Well-specified
requirements are crucial for good software design; they depend on the understanding of the domain. Thus, domain engineering
becomes an essential activity. The possibility to have a formal model of a domain, consistent with the use of formal methods
for developing critical software working within it, is an important issue. Safety-critical domains, like transportation, exhibit
interesting features, such as high levels of nondeterminism, complex interactions, stringent safety properties, and multifaceted
timing attributes. The formal representation of these features is a challenging task. We explore the possibility of utilizing
Event-B as a domain engineering tool. We discuss the problems we faced during this exercise and how we tackled them. Special
attention is devoted to the issue of the validation of the model, in particular with a technique based on the animation of
specifications. Event-B is mature enough to be an effective tool to model domains except in some areas, temporal properties
mainly, where more work is still needed. 相似文献
956.
We describe a simple algorithm for estimating the 3-D motion of isolated targets in infrared image sequences. The algorithm is based on analyzing the changes in the shapes and the relative positions of segmented image regions. Experimental results of applying this algorithm to single IR images and to an image sequence are presented. 相似文献
957.
Christian Brunette Jean-Pierre Talpin Abdoulaye Gamatié Thierry Gautier 《The Journal of Logic and Algebraic Programming》2009,78(4):233-259
This article presents the development of a metamodel and an open-source design environment for the synchronous language Signal in the Gme and Eclipse frameworks. This environment is intended to be used as a pivot modeling tool for a customized, aspect-oriented and application-driven, computer-aided engineering of embedded systems starting from multiple and heterogeneous initial specifications. The metamodel, called SignalMeta, is defined on top of the design workbench Polychrony, which is dedicated to Signal programming. Automated transformations are defined and implemented in order to produce, analyze, statically verify and model-check programs obtained from high-level models.The proposed approach promotes model-driven engineering within a framework that strongly favors formal validation. It aims at significantly decreasing design costs while improving the quality of systems. We demonstrate the agility of this approach by considering the design of both control-oriented and avionic systems. We start with an implementation of core polychronous1 data-flow concepts in Gme and show the ease of its modular extension with application-specific concepts such as mode automata or integrated modular avionics concepts. This work is the first attempt to generalize the formal model of computation and the design philosophy of Polychrony. 相似文献
958.
959.
Dr. Rayane Ghoteimi Dr. Abdennour Braka Céline Rodriguez Emeline Cros-Perrial Dr. Valentin Duvauchelle Dr. Jean-Pierre Uttaro Prof. Dr. Christophe Mathé Dr. Christine Ménétrier-Caux Dr. Lars Petter Jordheim Dr. Laurent Chaloin Dr. Suzanne Peyrottes 《ChemMedChem》2023,18(7):e202200594
Various series of 4,6-biaryl-2-thiopyridine derivatives were synthesized and evaluated as potential ecto-5′-nucleotidase (CD73) inhibitors. Two synthetic routes were explored and the coupling of 4,6-disubstituted 3-cyano-2-chloro-pyridines with selected thiols allowed us to explore the structural diversity. Somehow divergent results were obtained in biological assays on CD73 inhibition using either the purified recombinant protein or cell-based assays, highlighting the difficulty to target protein-protein interface on proteins existing as soluble and membrane-bound forms. Among the 18 new derivatives obtained, three derivatives incorporating morpholino substituents on the 4,6-biaryl-2-thiopyridine core were shown to be able to reverse the adenosine-mediated immune suppression on human T cells. The higher blockade efficiency was observed for 2-((3-cyano-4,6-bis(4-morpholinophenyl)pyridin-2-yl)thio)-N-(isoxazol-3-yl)acetamide (with total reversion at 100 μM) and methyl 2-((3-cyano-4,6-bis(4-morpholinophenyl)pyridin-2-yl)thio)acetate (with partial reversion at 10 μM). Thus, this series of compounds illustrates a new chemotype of CD73 allosteric inhibitors. 相似文献