全文获取类型
收费全文 | 2380篇 |
免费 | 207篇 |
专业分类
电工技术 | 21篇 |
综合类 | 29篇 |
化学工业 | 965篇 |
金属工艺 | 25篇 |
机械仪表 | 43篇 |
建筑科学 | 104篇 |
矿业工程 | 6篇 |
能源动力 | 54篇 |
轻工业 | 379篇 |
水利工程 | 41篇 |
石油天然气 | 4篇 |
无线电 | 83篇 |
一般工业技术 | 383篇 |
冶金工业 | 145篇 |
原子能技术 | 7篇 |
自动化技术 | 298篇 |
出版年
2024年 | 15篇 |
2023年 | 28篇 |
2022年 | 175篇 |
2021年 | 179篇 |
2020年 | 97篇 |
2019年 | 85篇 |
2018年 | 89篇 |
2017年 | 93篇 |
2016年 | 109篇 |
2015年 | 93篇 |
2014年 | 126篇 |
2013年 | 171篇 |
2012年 | 141篇 |
2011年 | 203篇 |
2010年 | 122篇 |
2009年 | 117篇 |
2008年 | 127篇 |
2007年 | 96篇 |
2006年 | 70篇 |
2005年 | 50篇 |
2004年 | 46篇 |
2003年 | 49篇 |
2002年 | 44篇 |
2001年 | 28篇 |
2000年 | 29篇 |
1999年 | 28篇 |
1998年 | 33篇 |
1997年 | 22篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有2587条查询结果,搜索用时 15 毫秒
81.
Degani Asaf Goldman Claudia V. Deutsch Omer Tsimhoni Omer 《Cognition, Technology & Work》2017,19(2-3):211-231
Cognition, Technology & Work - This paper presents an approach to human–machine interactions based on the concept of teamwork and the psychological theory of object relations. We envision... 相似文献
82.
This article reports an extraction–purification of napins from an industrial rapeseed meal and the assessment of their antimicrobial activity against Fusarium langsethiae. The best extraction conditions are observed at pH 2, 12% (w/w) of rapeseed meal after 15 min of extraction in water at room temperature. Under these conditions the extraction is highly selective, allowing a simple purification process (ammonium sulfate precipitation followed by desalting size exclusion chromatography) to get purified napins. These napins possessed significant anti-Fusarium activity (IC50 = 70 μM) and a compact secondary structure rich in α-helix, which may explain this bioactivity. 相似文献
83.
84.
85.
86.
Alejandra Vesga-Baron Claudia Etchebehere M. Cristina Schiappacasse Rolando Chamy Estela Tapia-Venegas 《International Journal of Hydrogen Energy》2021,46(7):5074-5084
The oxidation-reduction potential (ORP) is an important factor in H2 production via dark fermentation however its effect over microbial diversity in an acidogenic sludge has not, been well studied. This work studies the effect of ORP controlled by hydrogen peroxide and potassium ferricyanide on continuous hydrogen production and microbial diversity in an acidogenic sludge fed (HRT 12 h and pH 5.5) with glycerol. Results show that the more oxidizing ORP control environment (?540 mV) improves H2 yield by 50–70% (0.31–0.51 molH2/mol glycerol) over non-ORP control conditions. Oxidizing ORP values were shown to enrich microorganisms of the genus Clostridium, which have been linked to high H2 yields. Therefore, controlling ORP in an acidogenic sludge was shown to directly modify microbial diversity at the genus level, and could likely to indirectly regulate metabolic function. Additionally, metabolic pathways were regulated by the kind of agent used. 相似文献
87.
Enhancement effect on apparent viscosity of aqueous tragacanth gum dispersions promoted by sugars 下载免费PDF全文
Claudia Silva María D. Torres Ramon Moreira Francisco Chenlo 《International Journal of Food Science & Technology》2017,52(12):2677-2683
Flow curves of aqueous dispersions of tragacanth gum (T) with sucrose and glucose at different temperatures were determined using a controlled‐stress rheometer. The effect of sodium chloride without or with sucrose (at the highest content) on the rheology of T dispersions was evaluated. The presence of sucrose and glucose promoted a noticeable enhancement impact on the apparent viscosity of aqueous T dispersions, which depended on sugar type/content, shear rate and temperature. In all cases, the glucose addition led to the largest enhanced viscosities at low shear rates (<10 s?1) and temperature. The joint action of sugar and salt exhibited a notable effect on apparent viscosity at low shear rates, softening the strong shear‐thinning behaviour of T samples. Flow curves of T in the presence of sugars were satisfactorily described by the Cross‐Williamson model, being semi‐empirical correlations of the model parameters with ingredients content and temperature stablished. 相似文献
88.
Abstract When an extraordinary wave under inhibited reflection conditions is incident on an interface between a uniaxial crystal and an isotropic medium, the reflected extraordinary wave is evanescent and the polarization of the refracted wave changes from linear to elliptical. In the present paper it is shown that the refracted ray undergoes a shift which is not only longitudinal (as the Goos—Hänchen effect in total reflection in isotropic interfaces) but also transversal. The structure of the evanescent reflected wave is studied and the polarization of the transmitted wave is analysed. 相似文献
89.
L. Viridiana Soto-Robles María Fernanda Lpez Vernica Torres-Banda Claudia Cano-Ramírez Gabriel Obregn-Molina Gerardo Zúiga 《International journal of molecular sciences》2021,22(1)
Dendroctonus-bark beetles are natural agents contributing to vital processes in coniferous forests, such as regeneration, succession, and material recycling, as they colonize and kill damaged, stressed, or old pine trees. These beetles spend most of their life cycle under stem and roots bark where they breed, develop, and feed on phloem. This tissue is rich in essential nutrients and complex molecules such as starch, cellulose, hemicellulose, and lignin, which apparently are not available for these beetles. We evaluated the digestive capacity of Dendroctonus rhizophagus to hydrolyze starch. Our aim was to identify α-amylases and characterize them both molecularly and biochemically. The findings showed that D. rhizophagus has an α-amylase gene (AmyDr) with a single isoform, and ORF of 1452 bp encoding a 483-amino acid protein (53.15 kDa) with a predicted signal peptide of 16 amino acids. AmyDr has a mutation in the chlorine-binding site, present in other phytophagous insects and in a marine bacterium. Docking analysis showed that AmyDr presents a higher binding affinity to amylopectin compared to amylose, and an affinity binding equally stable to calcium, chlorine, and nitrate ions. AmyDr native protein showed amylolytic activity in the head-pronotum and gut, and its recombinant protein, a polypeptide of ~53 kDa, showed conformational stability, and its activity is maintained both in the presence and absence of chlorine and nitrate ions. The AmyDr gene showed a differential expression significantly higher in the gut than the head-pronotum, indicating that starch hydrolysis occurs mainly in the midgut. An overview of the AmyDr gene expression suggests that the amylolytic activity is regulated through the developmental stages of this bark beetle and associated with starch availability in the host tree. 相似文献
90.
Anat Akiva Johanna Melke Sana Ansari Nalan Liv Robin van der Meijden Merijn van Erp Feihu Zhao Merula Stout Wouter H. Nijhuis Cilia de Heus Claudia Muñiz Ortera Job Fermie Judith Klumperman Keita Ito Nico Sommerdijk Sandra Hofmann 《Advanced functional materials》2021,31(17):2010524
Bone formation (osteogenesis) is a complex process in which cellular differentiation and the generation of a mineralized organic matrix are synchronized to produce a hybrid hierarchical architecture. To study the mechanisms of osteogenesis in health and disease, there is a great need for functional model systems that capture in parallel, both cellular and matrix formation processes. Stem cell-based organoids are promising as functional, self-organizing 3D in vitro models for studying the physiology and pathology of various tissues. However, for human bone, no such functional model system is yet available. This study reports the in vitro differentiation of human bone marrow stromal cells into a functional 3D self-organizing co-culture of osteoblasts and osteocytes, creating an organoid for early stage bone (woven bone) formation. It demonstrates the formation of an organoid where osteocytes are embedded within the collagen matrix that is produced by the osteoblasts and mineralized under biological control. Alike in in vivo osteocytes, the embedded osteocytes show network formation and communication via expression of sclerostin. The current system forms the most complete 3D living in vitro model system to investigate osteogenesis, both in physiological and pathological situations, as well as under the influence of external triggers (mechanical stimulation, drug administration). 相似文献