全文获取类型
收费全文 | 127篇 |
免费 | 6篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 27篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 8篇 |
轻工业 | 23篇 |
无线电 | 4篇 |
一般工业技术 | 26篇 |
冶金工业 | 25篇 |
自动化技术 | 16篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 4篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有133条查询结果,搜索用时 15 毫秒
41.
Dr. Bernhard Wagner Thomas Walter Dr. Thomas Himmelsbach Patrick Clos Antje Beer Dr. D?rte Budziak Dr. Thomas Dreher Dr. Hans-Gerhard Fritsche Mathias H��bschmann Dr. Silke Marczinek Annett Peters Heidrun Poeser Hannsj?rg Schuster Dr. Anke Steinel Frank Wagner Dr. Gunther Wirsing 《Grundwasser》2011,16(3):155-162
One of the main objectives of the EC water framework directive is to ensure good chemical status for all groundwater bodies. For this reason the geological surveys of Germany have produced a nationwide map of the background values of groundwater. Only naturally occurring inorganic parameters were taken into account, including the relevant major and trace elements. Based on the hydrogeological map of Germany at the scale of 1:200,000 (HüK 200), and its delimited hydrogeological regions, a total of 186 hydrogeochemical units were defined and mapped geochemically. This involved collection of more than 52,000 groundwater samples in a database and allocation to their appropriate hydrogeochemical units. In order to separate anomalies within the data-sets from the underlying normal population, probability nets were used as a statistical tool. The procedure allowed to determine the normal populations of the investigated parameters within the hydrogeochemical units and to quantify them in the form of percentiles. The resulting hydrogeochemical background values are accessible through an internet web map service that includes an online map application. The main intention of this technical note is to inform the reader about the existing internet service, which necessitates some web-site content duplication. 相似文献
42.
The effect of sorption to dissolved humic acids (HAs) on the chlorination of PAHs in aqueous solution was studied. The addition of HA accelerated the chlorination of fluoranthene and naphthalene in hypochlorite solutions at pH 5, the stronger effect being observed for fluoranthene that is sorbed to a higher extent than naphthalene. Sorption coefficients (K(DOC)) of the analytes were determined by solid-phase microextraction (SPME). The observed rate constant for fluoranthene chlorination is, for example, larger by a factor of 5 in the presence of 10 mg L(-1) of an aquatic HA as compared to HA-free solution (k' = 0.02 h(-1) at 60 mg L(-1) active chlorine, pH 5, without HA). While Cl2 is the dominant reactive species in pure aqueous solution for both PAHs, the reaction of fluoranthene seems to involve an additional pathway of chlorination by HOCl in the presence of HA. It was found that not only did HA not protect PAHs from the electrophilic attack of the chlorinating species, but the sorption of PAHs on the hydrophobic domains of the HA favored instead the extent of the chlorination reaction. 相似文献
43.
44.
45.
We describe herein a platform to study protein-protein interactions and to form functional protein complexes in nanoscopic surface domains. For this purpose, we employed multivalent chelator (MCh) templates, which were fabricated in a stepwise procedure combining dip-pen nanolithography (DPN) and molecular recognition-directed assembly. First, we demonstrated that an atomic force microscope (AFM) tip inked with an oligo(ethylene glycol) (OEG) disulfide compound bearing terminal biotin groups can be used to generate biotin patterns on gold achieving line widths below 100 nm, a generic platform for fabrication of functional nanostructures via the highly specific biotin-streptavidin recognition. Subsequently, we converted such biotin/streptavidin patterns into functional MCh patterns for reversible assembly of histidine-tagged (His-tagged) proteins via the attachment of a tris-nitriloacetic acid (trisNTA) biotin derivative. Fluorescence microscopy confirmed reversible immobilization of the receptor subunit ifnar2-His10 and its interaction with interferon-alpha2 labeled with fluorescent quantum dots in a 7 x 7 dot array consisting of trisNTA spots with a diameter of approximately 230 nm. Moreover, we carried out characterization of the specificity, stability, and reversibility as well as quantitative real-time analysis of protein-protein interactions at the fabricated nanopatterns by imaging surface plasmon resonance. Our work offers a route for construction and analysis of functional protein-based nanoarchitectures. 相似文献
46.
Mariana Calin Annett Gebert Andreea Cosmina Ghinea Petre Flaviu Gostin Somayeh Abdi Christine Mickel Jürgen Eckert 《Materials science & engineering. C, Materials for biological applications》2013,33(2):875-883
Ti-based metallic glasses show high potential for implant applications; they overcome in several crucial respects their well-established biocompatible crystalline counterparts, e.g. improved corrosion properties, higher fracture strength and wear resistance, increased elastic strain range and lower Young's modulus. However, some of the elements required for glass formation (e.g. Cu, Ni) are harmful for the human body. We critically reviewed the biological safety and glass forming tendency in Ti of 27 elements. This can be used as a basis for the future designing of novel amorphous Ti-based implant alloys entirely free of harmful additions. In this paper, two first alloys were developed: Ti75Zr10Si15 and Ti60Nb15Zr10Si15. The overheating temperature of the melt before casting can be used as the controlling parameter to produce fully amorphous materials or bcc-Ti-phase reinforced metallic glass nano-composites. The beneficial effect of Nb addition on the glass-formation and amorphous phase stability was assessed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. Crystallization and mechanical behavior of ribbons are influenced by the amount and distribution of the nano-scaled bcc phase existing in the as-cast state. Their electrochemical stability in Ringer's solution at 310 K was found to be significantly better than that of commercial Ti-based biomaterials; no indication for pitting corrosion was recorded. 相似文献
47.
Burns Lindsay H.; Annett Lucy; Kelly Ann E.; Everitt Barry J.; Robbins Trevor W. 《Canadian Metallurgical Quarterly》1996,110(1):60
The effects of bilateral excitotoxic lesions of 3 major sources of afferents to the ventral striatum (nucleus accumbens) were compared on an open field test of food neophobia allowing the choice between familiar and novel food. Whereas lesions of the basolateral amygdala and ventral subiculum had qualitatively similar effects to reduce food neophobia (although not affecting the latency to eat), amygdala lesions increased and the ventral subiculum decreased locomotor activity. In contrast, damage to the ventromedial prelimbic prefrontal cortex only affected initial food choice and latency measures. By comparison, excitotoxic lesions of the nucleus accumbens itself and intra-accumbens infusion of the N-methyl-{d}-aspartate (NMDA) receptor antagonist AP5 increased activity and attenuated food neophobia. Results are discussed in terms of the role of limbic and prefrontal neuronal networks converging in the nucleus accumbens to control different aspects of the behavioral response to novelty. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
49.
Many low temperature properties of high Tc superconductors deviate significantly from the detailed predictions of BCS theory. Here we discuss whether these effects could be caused by either: (a) an unconventional pairing state, or (b) local randomness in the gap function due to the intrinsic disorder. We review recent experiments pertinent to these questions: Josephson effects in (001) oriented planar junctions between YBa2Cu3O7- and classic superconductors and the temperature dependence of the a-b plane electro-magnetic penetration depth at low temperatures. We also calculate the density of states of s-wave superconductors with local quenched disorder in the gap function so as to determine whether s-wave pairing could be consistent with the low energy quasiparticle excitations seen in many experiments. 相似文献
50.
Wilhelm M Wittsiepe J Schrey P Hilbig A Kersting M 《The Science of the total environment》2005,343(1-3):61-70
The dietary intake of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) was studied among young German children with different food consumption behaviour (consumption of own grown foodstuffs and of products from the supermarket). The study area comprised an industrialized and a rural area of West Germany. Dietary intake of contaminants was measured by the duplicate method according to the WHO guideline. A total 588 duplicate portions were collected daily from 84 individuals between May and September 1998. Intake of food groups was calculated from dietary records. Determination of As, Cd, Hg, and Pb was performed following high-pressure digestion of lyophilized samples by atomic absorption spectrometry (AAS). Geometric mean weekly intake [microg/(kgbw x week)] was as follows: As 1.4, Cd 2.3, Hg 0.16, and Pb 5.3. Geometric mean intake corresponded to the percentage of the provisional tolerable weekly intake (PTWI) as follows: As 9.7%, Cd 32%, Hg 3.3%, Pb 21%. As and Hg intake were mainly influenced by fish consumption. The amount of cereals and bakery wares mainly determined the Cd and Pb intake. Children living in the industrialized area with a substantial food consumption of own grown vegetables or products from domestic animals products had no increased dietary intake of the metals. 相似文献