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491.
In the solid oxide fuel cell (SOFC) field, proton conducting perovskite electrolytes offer many potential benefits. However, an issue with these electrolytes is their stability at elevated temperatures in the presence of CO2. Recently we have reported enhanced oxide ion/proton conductivity in oxyanion (silicate, phosphate) doped Ba2In2O5, and in this paper we extend this work to examine the stability at elevated temperatures towards CO2. The results show improved CO2 stability compared to the undoped system, and moreover this can be further improved by co-doping on either the Ba site with La, or the In site with Zr. While this co-doping strategy does reduce the conductivity slightly, the greatly improved CO2 stability would suggest there is technological potential for these co-doped samples.  相似文献   
492.
Quantum Information Processing - Covert communication methods are used in the communication with high security level. When it turns to quantum communication, covertness is also an important concern...  相似文献   
493.
Clean Technologies and Environmental Policy - This study investigated the viability of a vibratory nanofiltration system as a low-energy alternative to evaporation in concentrating coffee extracts...  相似文献   
494.
Hypocalcemia affects almost 50% of all dairy cows. Our laboratory has previously demonstrated that infusions of the serotonin precursor 5-hydroxy-l-tryptophan (5-HTP) increase circulating calcium concentrations in the Holstein transition cow. It is unknown whether feeding a negative dietary cation-anion difference (DCAD) diet alters the relationship between 5-HTP and hypocalcemia. The main objective of this study was to determine whether feeding a negative DCAD (?DCAD) diet before calving in conjunction with 5-HTP treatment could further diminish the magnitude of hypocalcemia at the time of calving. We used a randomized complete block design with a 2 × 2 factorial arrangement. Thirty-one multiparous Holstein cows were fed either a positive (+13 mEq/100 g) or negative (?13 mEq/100 g) DCAD diet 21 d before parturition and were intravenously infused daily with saline or 5-HTP (1 mg/kg) starting 7 d before the estimated date of parturition. Cows were blocked by parity and were randomly assigned to 1 of 4 treatment groups: positive DCAD plus saline, positive DCAD plus 5-HTP, negative DCAD plus saline, and negative DCAD plus 5-HTP, resulting in n = 8 per group. Total calcium (tCa), ionized calcium (iCa), and feed intake were recorded. The iCa was elevated prepartum in the ?DCAD/5-HTP group compared with the other treatment groups as well as on d 0 and 1 postpartum. Although differences in tCa were not significant across the pre- or postpartum periods, tCa was numerically higher on d 0 and significantly higher on d 1 in ?DCAD/5-HTP cows compared with all other groups. Prepartum the ?DCAD/5-HTP treatment group ate less than the other treatment groups; however, postpartum dry matter intake differences were not significant. These findings demonstrate that feeding a ?DCAD diet in conjunction with 5-HTP prepartum can increase postpartum circulating iCa concentrations and therefore diminish the magnitude of hypocalcemia at the time of parturition.  相似文献   
495.
It has been hypothesized that the emotionality of the female rat is reduced at estrus. In confirmation of previous research, the present 5 experiments with 112 Ss show that administration of estradiol benzoate (20 mug/kg) to female rats of the Maudsley Reactive (MR) strain increased open-field activity and decreased open-field defecation. In addition, ovariectomy increased open-field defecation in MR females. Supporting the generality of these findings, hormone administration reduced open-field defecation and increased open-field activity in intact females of a genetically heterogeneous background. Additional studies suggest that the decrease in open-field defecation at estrus is dependent on estrogenic suppression of food intake. Hormone replacement decreased food intake in the period preceding the open-field test, and colonic contents were also lower in rats treated with estradiol benzoate plus progesterone immediately after the completion of the open-field test. These changes were seen in both MR and genetically heterogeneous females. It is concluded that the decrease in open-field defecation at estrus may be mediated by a reduction in food intake and a consequent decrease in colonic contents and that the validity of the defecation response as a measure of emotionality may be seriously questioned under these circumstances. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
496.
Sedimentation velocities and drop sizes have been observed in batch dispersions of two immiscible liquids during collapse of the dispersion created by agitation in a tank. It is shown that existing relationships between particle size, sedimentation velocity and fractional hold-up of dispersed phase can be used to obtain characteristic drop sizes from data on sedimentation velocity and hold-up in batch tests. This sedimentation technique is simple and rapid but approximate. It may be used to estimate drop sizes in stirred tanks when other methods usually fail, for example when the liquids are strongly coloured or hold-up of the dispersed phase is near 50%. In industrial laboratories interpretation of the characteristics of a particular system, particularly sensitivity of drop size to stirring conditions, will improve mixer-settler design procedures for example. It is unlikely that sophisticated photographic techniques will be widely used in this role.  相似文献   
497.
The authors charted growth of reading vocabulary for first- through fourth-grade students at three dissimilar elementary schools: School A, a suburban school enrolling White students who spoke standard English; School B, an inner-city school enrolling Black, dialect-speaking students; and School C, a semirural school enrolling economically disadvantaged, dialect-speaking Asian/Pacific students. Multiple-choice and interview tests showed rapid growth of reading vocabulary to an impressive size for all students. However, mainstream (School A) students had larger reading vocabularies, decoded more words, and knew more word meanings than the disadvantaged students at Schools B and C. The gap between mainstream and disadvantaged students was largest for infrequent words. The data suggest that direct instruction in decoding and/or individual word meanings could play a limited role in assisting minority students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
498.
This paper describes a program which provides an interactive command driven interface to the Graphical Kernel System (GKS).  相似文献   
499.
Novel bacterial (HT) and fungal (FPII) food‐grade protease preparations were evaluated for their ability to hydrolyse sheep cheese whey (SCW) and the generation of bioactive peptides. Both protease preparations hydrolysed the whey proteins to small peptides over 24‐h hydrolysis time, but the time course hydrolysis profiles were different as evaluated by SDS‐PAGE. The HT whey hydrolysate had considerably higher antioxidant and angiotensin‐I converting enzyme (ACE)‐inhibitor activity than the FPII hydrolysate. Neither hydrolysate was cytotoxic towards Vero cells. OFFGEL electrophoresis of the small peptide pool fraction (<15 amino acids) of each hydrolysate indicated differences in the pI distribution of the bioactive peptides. This likely reflects the diverse hydrolytic specificity of the proteases. Although the antioxidant activity of both hydrolysates was not significantly affected by simulated gastrointestinal digestion, the loss of ACE‐inhibitor activity was greater with the FPII hydrolysate.  相似文献   
500.
Area 6 at Dover Air Force Base (Dover, DE) has been the location of an in-depth study by the RTDF (Remediation Technologies Development Forum Bioremediation of Chlorinated Solvents Action Team) to evaluate the effectiveness of natural attenuation of chlorinated ethene contamination in groundwater. Compound-specific stable carbon isotope measurements for dissolved PCE and TCE in wells distributed throughout the anaerobic portion of the plume confirm that stable carbon isotope values are isotopically enriched in 13C consistent with the effects of intrinsic biodegradation. During anaerobic microbial reductive dechlorination of chlorinated hydrocarbons, the light (12C) versus heavy isotope (13C) bonds are preferentially degraded, resulting in isotopic enrichment of the residual contaminant in 13C. To our knowledge, this study is the first to provide definitive evidence for reductive dechlorination of chlorinated hydrocarbons at a field site based on the delta13C values of the primary contaminants spilled at the site, PCE and TCE. For TCE, downgradient wells show delta13C values as enriched as -18.0/1000 as compared to delta13C values for TCE in the source zone of -25.0 to -26.0/1000. The most enriched delta13C value on the site was observed at well 236, which also contains the highest concentrations of cis-DCE, VC, and ethene, the daughter products of reductive dechlorination. Stable carbon isotope signatures are used to quantify the relative extent of biodegradation between zones of the contaminant plume. On the basis of this approach, it is estimated that TCE in downgradient well 236 is more than 40% biodegraded relative to TCE in the proposed source area.  相似文献   
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