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41.
Saari HK Schmidt S Coynel A Huguet S Schäfer J Blanc G 《The Science of the total environment》2007,382(2-3):304-310
The industrial basin of Decazeville (Riou-Mort watershed, South-West France) is well known for its heavy metal pollution and its subsequent environmental effects on the Lot-Garonne River system. The source of this pollution is the Riou-Mort River, which drains smelting waste areas. A first survey after remediation works has revealed elevated dissolved uranium (U(D)) concentrations in the outlet of the Riou-Mort River. The objective of this research is to identify the origin of U(D) in the Riou-Mort watershed and to evaluate the impact of industrial activities on this element. Uranium was measured at 10 water sampling sites, located upstream and downstream the industrial basin, and in three smelting waste deposits. Uranium concentrations in the smelting waste deposits reach up to 14.4 mg kg(-1) and (234U/238U) activity ratios (AR) are near unity. Dissolved U concentrations in the Riou-Mort River and its main tributaries ranges over two orders of magnitude from 0.02 to 6.1 microg L(-1). The highest levels were measured in a site with no anthropogenic pollution, upstream from the industrial area. This observation suggests that U(D) is mainly linked to weathering; the elevated U concentrations originate from the naturally occurring radioactive materials (NORM) located in the Permian bedrock and no significant U pollution exists, at present, in the Riou-Mort watershed. This work demonstrates that spatial monitoring coupled with a long time-series are an essential prerequisite in assessment of spatiotemporal variations of U(D), prior to a diagnostic of pollution in a small watershed. 相似文献
42.
To investigate the heat induced formation of α,β-unsaturated 4-hydroxy-aldehydes (4-hydroxy-2-trans-hexenal (HHE), 4-hydroxy-2-trans-octenal (HOE), 4-hydroxy-2-trans-nonenal (HNE) and 4-hydroxy-2-trans-decenal (HDE)) fatty acid methyl esters (FAMEs) of stearic, oleic, linoleic and linolenic acids were heated separately at
185°C for 0 to 6 hrs. The formation of 2,4-decadienal, a suspected intermediate in HNE formation, was also measured in these
FAMEs. As expected methyl stearate (MS) and methyl oleate (MO) did not produce any of the α,β-unsaturated 4-hydroxy-aldehydes
as a consequence of thermally induced lipid peroxidation. The formation of HHE was detected in both methyl linoleate (ML)
and methyl linolenate (MLN), with concentration higher in MLN than in ML. The maximum HHE concentration was 3.99 μg HHE/g
ML after 2 h and 50.78 μg HHE/g MLN after 4 h of heat treatment. HOE was detected in both ML and MLN, and the maximum concentration
was 102.50 μg HOE/g ML after 6 h and 90.56 μg HOE/g MLN after 2 h of heating. HNE was found only in ML and its highest concentration
was 84.82 μg HNE/g ML after 3 h of heating. HDE was not detected in any of the four heat treated FAMEs. 2,4-Decadienal was
not found to be an intermediate in the formation of HNE in thermally induced oxidation of FAMEs. 相似文献
43.
Teemu Suutari Tiina Silen Didem S˛en Karaman Heikki Saari Diti Desai Erja Kerkelä Saara Laitinen Martina Hanzlikova Jessica M. Rosenholm Marjo Yliperttula Tapani Viitala 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(45):6289-6300
The surface plasmon resonance technique in combination with whole cell sensing is used for the first time for real‐time label‐free monitoring of nanoparticle cell uptake. The uptake kinetics of several types of nanoparticles relevant to drug delivery applications into HeLa cells is determined. The cell uptake of the nanoparticles is confirmed by confocal microscopy. The cell uptake of silica nanoparticles and polyethylenimine–plasmid DNA polyplexes is studied as a function of temperature, and the uptake energies are determined by Arrhenius plots. The phase transition temperature of the HeLa cell membrane is detected when monitoring cell uptake of silica nanoparticles at different temperatures. The HeLa cell uptake of the mesoporous silica nanoparticles is energy‐independent at temperatures slightly higher than the phase transition temperature of the HeLa cell membrane, while the uptake of polyethylenimine–DNA polyplexes is energy‐dependent and linear as a function of temperature with an activation energy of Ea = 62 ± 7 kJ mol?1 = 15 ± 2 kcal mol?1. The HeLa cell uptake of red blood cell derived extracellular vesicles is also studied as a function of the extracellular vesicle concentration. The results show a concentration dependent behavior reaching a saturation level of the extracellular vesicle uptake by HeLa cells. 相似文献
44.
We define an operation called transposition on words of fixed length. This operation arises naturally when the letters of a word are considered as entries of a matrix. Words that are invariant with respect to transposition are of special interest. It turns out that transposition invariant words have a simple interpretation by means of elementary group theory. This leads us to investigate some properties of the ring of integers modulo n and primitive roots. In particular, we show that there are infinitely many prime numbers p with a primitive root dividing p+1 and infinitely many prime numbers p without a primitive root dividing p+1. We also consider the orbit of a word under transposition. 相似文献
45.
Rat and human urine samples were analyzed for lipophilic aldehydes and other carbonyl products of lipid peroxidation. The
following compounds were identified as their 2,4-dinitrophenyl hydrazones by cochromatography with pure standards using three
solvent systems: butanal, butan-2-one, pentan-2-one, hex-2-enal, hexanal, hepta-2,4-dienal, hept-2-enal, octanal, non-2-enal,
deca-2,4-dienal, 4-hydroxyhex-2-enal, and 4-hydroxynon-2-enal. In general, fasted rats excreted less of these compounds than
fed rats, indicating they were partially of dietary origin or that the endogenous compounds were excreted in a form not susceptible
to hydrazone formation. The compounds excreted in human urine were similar to those excreted in rat urine but were present
in lower concentrations. Identification of the conjugated forms fo the lipophilic aldehydes and related carbonyl compounds
excreted in urine may be a source of information about their reactions in vivo. 相似文献
46.
Formation of 4‐Hydroxy‐2‐Trans‐Nonenal,a Toxic Aldehyde,in Thermally Treated Olive and Sunflower Oils 下载免费PDF全文
Jieyao Yuan Don W. Shoeman A. Saari Csallany 《Journal of the American Oil Chemists' Society》2018,95(7):813-823
4‐Hydroxy‐2‐trans‐nonenal (HNE) is a toxic aldehyde produced mostly in oils containing polyunsaturated fatty acid due to heat‐induced lipid peroxidation. The present study examined the effects of the heating time, the degree of unsaturation, and the antioxidant potential on the formation of HNE in two light olive oils (LOO) and two sunflower oils (one high oleic and one regular) at frying temperature. HNE concentrations in these oil samples heated for 0, 1, 3, and 5 hours at 185 °C were measured using high‐performance liquid chromatography. The fatty‐acid distribution and the antioxidant capacity of these four oils were also analyzed. The results showed that all oils had very low HNE concentrations (<0.5 μg g?1 oil) before heating. After 5 hours of heating at 185 °C, HNE concentrations were increased to 17.98, 25.00, 12.51, and 40.00 μg g?1 in the two LOO, high‐oleic sunflower oil (HOSO), and regular sunflower oil (RSO), respectively. Extending the heating time increased HNE formation in all oils tested. It is related to their fatty‐acid distributions and antioxidant capacities. RSO, which contained high levels of linoleic acid (59.60%), a precursor for HNE, was more susceptible to degradation and HNE formation than HOSO and LOO, which contained only 6–8% linoleic acid. 相似文献
47.
48.
The first step in catabolism of the broadleaf herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is catalyzed by 2,4-D/alpha-ketoglutarate (alpha-KG)-dioxygenase (TfdA) in Ralstonia eutropha (formerly Alcaligenes eutrophus) JMP134. This oxygen- and ferrous-ion-dependent enzyme couples the oxidative decarboxylation of alpha-KG (yielding CO2 and succinate) with the oxidation of 2,4-D to produce 2,4-dichlorophenol and glyoxylate. TfdA was shown to utilize thiophenoxyacetic acid (TPAA) to produce thiophenol, allowing the development of a continuous spectrophotometric assay for the enzyme using the thiol-reactive reagent 4,4'-dithiodipyridine. In contrast to the reaction with 2,4-D, however, the kinetics of TPAA oxidation were nonlinear and ascorbic acid was found to be required for and consumed during TPAA oxidation. The ascorbic acid was needed to reduce a reversibly oxidized inactive state that was formed by reaction of the ferrous enzyme with oxygen, either in the absence of substrate or in the presence of TPAA. The dependency on this reductant was not due to an uncoupling of alpha-KG decarboxylation from substrate hydroxylation, as has been reported for several other alpha-KG-dependent hydroxylases. Significantly, the rate of formation of this reversibly oxidized species was much lower when the enzyme was turning over 2,4-D. Evidence also was obtained for the generation of an inactive enzyme species that could not be reversed by ascorbate. The latter species, not associated with protein fragmentation, arose from an oxidative reaction that is likely to involve hydroxyl radical reactions. On the basis of initial rate studies, the kcat and Km values for TPAA were estimated to be 20-fold lower and 80-fold higher than the corresponding values for 2,4-D. The results are incorporated into a model of TfdA reactivity involving both catalytic and inactivating events. 相似文献
49.
40 male first-line supervisors were randomly assigned to a behavioral modeling training program or to a control group. The training was designed to improve supervisors' interpersonal skills in dealing with their employees. The training program produced highly favorable trainee reactions, which were maintained over time. Moreover, the performance of the trainees was significantly better than that of supervisors in the control group on a learning test administered 6 mo after training, on behavioral simulations collected 3 mo after training, and on performance ratings collected on the job 1 yr after training. After the control group received the training, they achieved significant improvement in their supervisory skills and did not differ from the trainees who had originally undergone the training on any of the measures. The modeling films, developed by M. Sorcher (A. Goldstein and M. Sorcher, 1974) were based primarily on A. Bandura's (1977) principles of social-learning theory. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
50.
Diseases of yearling feedlot cattle in Colorado 总被引:6,自引:0,他引:6
R Jensen RE Pierson PM Braddy DA Saari LH Lauerman JJ England DP Horton AE McChesney 《Canadian Metallurgical Quarterly》1976,169(5):497-499
During all of 1974 we surveyed, for illnesses and deaths, about 407,000 yearling feedlot cattle. The morbidity was 5.1%, with a case mortality of 18.9% and a population mortality of 1.0%. Both morbidity and mortality were higher during fall and winter than during spring and summer. Of the 3,943 dead cattle, 1,988 were necropsied. The most prevalent diseases were: pneumonia, 48%; diphtheria, 6%; brisket disease, 6%; hemorrhagic colitis, 5%; riding injury, 4%; bloat, 3%; calculosis, 2%; endocarditis, 2%; abomasal ulcers, 2%; bovine viral diarrhea, 2%; embolic pulmonary aneurysm, 1%; and pulmonary edema, 1%. 相似文献