全文获取类型
收费全文 | 554篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 173篇 |
金属工艺 | 4篇 |
机械仪表 | 8篇 |
建筑科学 | 27篇 |
能源动力 | 10篇 |
轻工业 | 138篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 36篇 |
一般工业技术 | 98篇 |
冶金工业 | 46篇 |
原子能技术 | 1篇 |
自动化技术 | 51篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 32篇 |
2021年 | 36篇 |
2020年 | 20篇 |
2019年 | 26篇 |
2018年 | 32篇 |
2017年 | 22篇 |
2016年 | 26篇 |
2015年 | 25篇 |
2014年 | 13篇 |
2013年 | 28篇 |
2012年 | 26篇 |
2011年 | 47篇 |
2010年 | 30篇 |
2009年 | 16篇 |
2008年 | 30篇 |
2007年 | 25篇 |
2006年 | 22篇 |
2005年 | 22篇 |
2004年 | 15篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有606条查询结果,搜索用时 15 毫秒
61.
Johanna Just 《建筑学研究前沿(英文版)》2022,11(6):1205-1213
The environmental crisis has created a demand for practices that build awareness about the interconnections of diverse forms of life, allowing humans to understand complex earthly relationships and reconnect with the land they inhabit. This paper contributes to this debate by investigating bird watching activities and their relevance for architects and landscape architects. Drawing upon multispecies studies and the notion of landscape thinking, it examines the potential of birding as a caring landscaping practice. It analyzes the relationship between birders and sand martins in two case studies and probes how birders develop attentiveness for the birds and their shared environment. The investigation suggests that birding fosters care beyond the observed species. It can trigger a landscaping practice comparable to landscape thinking that helps humans reconnect with the land, fostering response-able spatial design practices. 相似文献
62.
Alejandro M. Alcaraz Johanna Eva Maria Schmidt Paolo Colombo Carlos Martinez 《Journal of the European Ceramic Society》2021,41(6):3314-3320
Stop flow lithography (SFL) combines aspects of microfluidic and photolithography to continuously fabricate particles with uniform planar shapes as dictated by a mask. In this work we aim to expand the palette of materials suitable for SFL processing by investigating the use of UV-crosslinkable preceramic polymers to make ceramic particles. A commercially available methacrylated-polysiloxane was used as the preceramic polymer and was mixed with 2.5 wt% Irgacure 651 photoinitiator. A simple SFL system was assembled to continuously fabricate UV-crosslinked preceramic polymer particles in the shape of hexagons, triangles, and gears with diameters ranging from 100 to 200 μm and thicknesses of 74 μm +/- 4 μm. Particles were harvested from the excess preceramic solution, cleaned and then pyrolyzed at 1000 °C to transform them into silicon oxycarbide ceramic particles. Particle shape was maintained during pyrolysis despite a ~80 % linear shrinkage due to the removal of acryl and methyl side groups, as confirmed via FTIR. After pyrolysis the outer diameters of the SiOC particles ranged from 20 to 40 μm with thicknesses of 10 μm–12 μm. Pyrolyzed particles were successfully recovered and dispersed in water. This work demonstrates a robust path for the fabrication of ceramic particles with specific shapes from preceramic polymers via SFL. 相似文献
63.
Vanessa Kohl Oliver Drews Victor Costina Miriam Bierbaum Ahmed Jawhar Henning Roehl Christel Weiss Susanne Brendel Helga Kleiner Johanna Flach Birgit Spiess Wolfgang Seifarth Daniel Nowak Wolf-Karsten Hofmann Alice Fabarius Henning D. Popp 《International journal of molecular sciences》2021,22(11)
Non-targeted effects (NTE) of ionizing radiation may initiate myeloid neoplasms (MN). Here, protein mediators (I) in irradiated human mesenchymal stromal cells (MSC) as the NTE source, (II) in MSC conditioned supernatant and (III) in human bone marrow CD34+ cells undergoing genotoxic NTE were investigated. Healthy sublethal irradiated MSC showed significantly increased levels of reactive oxygen species. These cells responded by increasing intracellular abundance of proteins involved in proteasomal degradation, protein translation, cytoskeleton dynamics, nucleocytoplasmic shuttling, and those with antioxidant activity. Among the increased proteins were THY1 and GNA11/14, which are signaling proteins with hitherto unknown functions in the radiation response and NTE. In the corresponding MSC conditioned medium, the three chaperones GRP78, CALR, and PDIA3 were increased. Together with GPI, these were the only four altered proteins, which were associated with the observed genotoxic NTE. Healthy CD34+ cells cultured in MSC conditioned medium suffered from more than a six-fold increase in γH2AX focal staining, indicative for DNA double-strand breaks, as well as numerical and structural chromosomal aberrations within three days. At this stage, five proteins were altered, among them IQGAP1, HMGB1, and PA2G4, which are involved in malign development. In summary, our data provide novel insights into three sequential steps of genotoxic signaling from irradiated MSC to CD34+ cells, implicating that induced NTE might initiate the development of MN. 相似文献
64.
Getinet Mekuriaw Tarekegn Johanna Karlsson Cecilia Kronqvist Britt Berglund Kjell Holtenius Erling Strandberg 《Journal of dairy science》2021,104(4):4424-4440
High-yielding dairy cows are often fed high proportions of cereal grain and pulses. For several reasons, it would be desirable to replace these feed sources with forage, which is not suitable for human consumption. Feeding large amounts of forage to dairy cows could also make dairy production more publicly acceptable in the future. In this study, we estimated genetic parameters for total dry matter intake (DMI), DMI from forage (DMIFor), energy-corrected milk (ECM), and ECM produced from forage (ECMFor). A total of 1,177 lactations from 575 cows of Swedish Red (SR) and Holstein (HOL) dairy breeds were included in the study. Mixed linear animal random regression models were used, with fixed effect of calving season and lactation week nested within parity 1 and 2+, fixed effect of calving year, and random regression coefficients for breeding value (up to linear) and permanent environmental effect (up to quadratic) of the cow. Heritability for DMI and DMIFor was generally higher for HOL than for SR in all-parity data and in later parities; however, the opposite was true for first parity. Heritability for DMI and DMIFor during the first 8 wk averaged 0.11 and 0.15, respectively, in all-parity data for the 2 breeds. Corresponding values for ECMFor and ECM were 0.21 and 0.29, respectively. In first parity, values were 0.32, 0.36, 0.28, and 0.51, respectively. The genetic correlation between DMI and DMIFor was high, above 0.83, and fairly constant across the lactation. The genetic correlation between ECMFor and ECM was close to unity in the later part of lactation for both breeds, but was around 0.8 in the early lactation for both breeds; it decreased for HOL to 0.54 in wk 17. The genetic correlations between DMI and ECMFor and between DMIFor and ECMFor were low and negative for HOL (absolute value ~0.2–0.3), but changed for SR from weakly positive in early lactation to negative values and back to positive toward the end of lactation. For most traits, the correlation between wk 1 and wk 8 into the lactation was very high; the lowest value was for DMI in HOL at 0.81. The genetic correlation between parities was rather high in the first part of the lactation. During the first 8 wk, the correlation was lower for HOL than for SR, except for ECM. We found that DMIFor and ECMFor showed reasonably large heritability, and future work should explore the possibility of genomic evaluations. 相似文献
65.
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
66.
67.
68.
Hot electrons emitted from thin oxide film-coated heavily doped silicon electrodes by cathodic pulse polarization can induce electrochemiluminescence from luminophores. The intensity of electrochemiluminescence produced at the electrode surface is dependent on the features of thin oxide films formed by thermal oxidation. As a preliminary study, we investigated the effect of thermal oxide growth conditions on the intensity of electrochemiluminescence produced at these electrodes, such as oxidation atmospheres, oxidation temperature, oxidation time and pre-treatment of wafers, using ruthenium(II) tris-(2,2′-bipyridine) chelate as a model luminophore. Optimal oxidation conditions of heavily doped silicon electrodes were obtained for the generation of intense electrochemiluminescence at this kind of silicon electrodes. 相似文献
69.
Streptococcus parauberis associated with modified atmosphere packaged broiler meat products and air samples from a poultry meat processing plant 总被引:1,自引:0,他引:1
Koort J Coenye T Vandamme P Björkroth J 《International journal of food microbiology》2006,106(3):318-323
Lactic acid bacteria (LAB) isolated from marinated or non-marinated, modified atmosphere packaged (MAP) broiler leg products and air samples of a large-scale broiler meat processing plant were identified and analyzed for their phenotypic properties. Previously, these strains had been found to be coccal LAB. However, the use of a 16 and 23S rRNA gene RFLP database had not resulted in species identification because none of the typically meat-associated LAB type strains had clustered together with these strains in the numerical analysis of the RFLP patterns. To establish the taxonomic position of these isolates, 16S rRNA gene sequence analysis, numerical analysis of ribopatterns, and DNA-DNA hybridization experiments were done. The 16S rRNA gene sequences of three isolates possessed the highest similarities (over 99%) with the sequence of S. parauberis type strain. However, in the numerical analysis of HindIII ribopatterns, the type strain did not cluster together with these isolates. Reassociation values between S. parauberis type or reference strain and the strains studied varied from 82 to 97%, confirming that these strains belong to S. parauberis. Unexpectedly, most of the broiler meat-originating strains studied for their phenotypical properties did not utilize lactose at all and the same strains fermented also galactose very weakly, properties considered atypical for S. parauberis. This is, to our knowledge, the first report of lactose negative S. parauberis strains and also the first report associating S. parauberis with broiler slaughter and meat products. 相似文献
70.