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排序方式: 共有359条查询结果,搜索用时 15 毫秒
91.
Polybrominated diphenyl ether (PBDE) concentrations in house dust are related to hormone levels in men 总被引:2,自引:0,他引:2
John D. Meeker Paula I. Johnson Russ Hauser 《The Science of the total environment》2009,407(10):3425-3429
Despite documented widespread human exposure to polybrominated diphenyl ethers (PBDEs) through dietary intake and contact with or inhalation of indoor dust, along with growing laboratory evidence for altered endocrine function following exposure, human studies of PBDE exposure and endocrine effects remain limited. We conducted a preliminary study within an ongoing study on the impact of environmental exposures on male reproductive health. We measured serum hormone levels and PBDE concentrations (BDE 47, 99 and 100) in house dust from 24 men recruited through a US infertility clinic. BDE 47 and 99 were detected in 100% of dust samples, and BDE 100 was detected in 67% of dust samples, at concentrations similar to those reported in previous US studies. In multivariable regression models adjusted for age and BMI, there was a statistically significant inverse relationship between dust PBDE concentrations and free androgen index. Dust PBDE concentrations were also strongly and inversely associated with luteinizing hormone (LH) and follicle stimulating hormone (FSH), and positively associated with inhibin B and sex hormone binding globulin (SHBG). Finally, consistent with limited recent human studies of adults, PBDEs were positively associated with free T4. In conclusion, the present study provides compelling evidence of altered hormone levels in relation to PBDE exposures estimated as concentrations in house dust, and that house dust is an important source of human PBDE exposure, but more research is urgently needed. 相似文献
92.
Gavin C. Jones Kirsten C. CorinRobert P. van Hille Susan T.L. Harrison 《Minerals Engineering》2011,24(11):1198-1208
Two types of laboratory mills, planetary and vibratory, were used to activate sulphide mineral concentrates mechanically before thermophilic (bio)leaching. These samples were analysed in terms of particle size, surface area, density, SEM, XRD line profile analysis and reactivity. The product particle size distributions indicated different particle breakage mechanisms of the two mills. The surface area for pyrite milled with the planetary mill was three fold that milled in the vibratory mill for the same length of time. Planetary milled samples showed lower densities, up to 4% less for pyrite samples, compared to vibratory milled samples. Particle surface oxidation, observed by SEM, occurred post milling. Surface oxidation products were more prevalent with planetary milled sulphide samples. XRD line profile analysis showed more line broadening effects with the planetary mill. This indicated that more bulk particle-related structural defects were present in the planetary milled samples. The reactivity in acidic solution was measured in terms of the generation of toxic reactive oxygen species (ROS): hydrogen peroxide and hydroxyl radicals. The ROS generation from milled sulphides, normalised to constant surface area loading, increased with increased mechanical activation. The planetary milled samples generated greater ROS per sample surface area than vibratory milled samples, more than 4-fold for pyrite after 60 min of milling. Increased ROS generation was postulated to result from increased surface area defects, solubilisation of iron oxidation products and bulk particle-related defects.The effect of mechanical activation on performance on thermophilic leaching and bioleaching tests was investigated using milled samples at 2% (w/v) pulp density. Short mill times improved leach rates from both mills, up to 7-fold cf. unactivated feed leach rates. Poor bioleaching performance resulted following long periods of mechanical activation (20-60 min). Pyrite and chalcopyrite bioleaching performance decreased dramatically above surface area loadings of 25 and 125 m2/L respectively. Planetary milled samples were less amenable to bioleaching. For pyrite milled for 20 and 60 min and chalcopyrite milled for 40 min, no viable cells were observed following inoculation via fluorescence microscopy, suggesting culture death supported by compromised ferrous iron oxidation. The generation of ROS was postulated to cause poor bioleaching performance under these conditions. 相似文献
93.
Synthese von porösen Kohlenstoffmonolithen unter Verwendung von Porenbeton als Templat. Teil II: Untersuchungen mechanischer Eigenschaften
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Michael Taubert Robert Heider Marcel Erlitz Eva Hille Andreas Lange Dirk Enke Olaf Klepel 《化学,工程师,技术》2015,87(7):998-1002
Monolithic forms are particularly suitable when using porous carbon materials in flow through apparatus. One method to synthesize these materials is the template‐assisted synthesis. Porous carbon monoliths have been prepared using porous concrete as a template. Systematic investigations of the mechanical stability have shown the potential of these materials for technical applications. It could be proven that the monoliths are stable against compressive stress and flow‐through of water, respectively. 相似文献
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Patrick P. Naulleau Christopher N. Anderson Jerrin Chiu Paul Denham Simi George Kenneth A. Goldberg Michael Goldstein Brian Hoef Russ Hudyma Gideon Jones Chawon Koh Bruno La Fontaine Andy Ma Warren Montgomery Dimitra Niakoula Joo-on Park Tom Wallow Stefan Wurm 《Microelectronic Engineering》2009,86(4-6):448-455
Microfield exposure tools continue to play a dominant role in the development of extreme ultraviolet (EUV) resists. Here we present an update on the SEMATECH Berkeley 0.3-NA microfield exposure tool and summarize the latest test results from high-resolution line-space printing. Printing down to 20-nm is presented with large process latitude at 22-nm half-pitch lines. Also presented are line-edge roughness results along with a discussion of the importance of mask contributors to line-edge roughness measured in resist. Finally we briefly describe an upgrade to the tool that will enable EUV resist development at the 16-nm half-pitch node and beyond. (This paper was presented in MNE 2008 conference, <http://www.mne08.org>, <http://www.mne-conf.org>). 相似文献
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99.
Inaugural diversity award winner is announced; law firm award,honorable mention go to two U.K. firms
Russ Bleemer 《Alternatives to the High Cost of Litigation》2009,27(2):18-25
The CPR Institute presents its first Award for Outstanding Contribution to Diversity in ADR, and its second set of honorees for the Law Firm Award for Excellence in ADR. Also, CPR offers mediation space, and more. 相似文献
100.
Many types of engineered surfaces have been observed to exhibit a fractal geometry. In some cases, modeling the generation of the surfaces predicts this and provides correlation between the dimension and history and properties of the surfaces. The complex process of machining precision surfaces does not yet lend itself to such detailed modeling, but observations of the correlations between production methods and surface dimension, independent of material type and hardness, offer encouragement. 相似文献