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71.
A method was developed to accurately predict the risk of injuries in industrial jobs based on datasets not meeting the assumptions of parametric statistical tools, or being incomplete. Previous research used a backward‐elimination process for feedforward neural network (FNN) input variable selection. Simulated annealing (SA) was used as a local search method in conjunction with a conjugate‐gradient algorithm to develop an FNN. This article presents an incremental step in the use of FNNs for ergonomics analyses, specifically the use of forward selection of input variables. Advantages to this approach include enhancing the effectiveness of the use of neural networks when observations are missing from ergonomics datasets, and preventing overspecification or overfitting of an FNN to training data. Classification performance across two methods involving the use of SA combined with either forward selection or backward elimination of input variables was comparable for complete datasets, and the forward‐selection approach produced results superior to previously used methods of FNN development, including the error back‐propagation algorithm, when dealing with incomplete data. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 31–49, 2004. 相似文献
72.
Children’s experiences of outdoor environments have been studied now for more than 40 years yet no research has specifically focussed on children’s experiences of water play in constructed spaces of city centres. This article discusses the development of an observational mapping tool, called TOWEC, to record the interaction of children with water. It then reports findings and analysis from observations over a year-long period of 3,399 children interacting with water in the award winning public open space of the Peace Gardens in the centre of the City of Sheffield, UK. The findings reveal that children undertake both active and passive activities associated with the constructed water features and that these activities are influenced by gender, age and temperature, but not ethnicity. The water features were not designed for children to play in but the children realise the potential affordance that the water features provide. 相似文献
73.
Karl T. Bates Linjie Wang Matthew Dempsey Sarah Broyde Michael J. Fagan Philip G. Cox 《Journal of the Royal Society Interface》2021,18(180)
Measures of attachment or accommodation area on the skeleton are a popular means of rapidly generating estimates of muscle proportions and functional performance for use in large-scale macroevolutionary studies. Herein, we provide the first evaluation of the accuracy of these muscle area assessment (MAA) techniques for estimating muscle proportions, force outputs and bone loading in a comparative macroevolutionary context using the rodent masticatory system as a case study. We find that MAA approaches perform poorly, yielding large absolute errors in muscle properties, bite force and particularly bone stress. Perhaps more fundamentally, these methods regularly fail to correctly capture many qualitative differences between rodent morphotypes, particularly in stress patterns in finite-element models. Our findings cast doubts on the validity of these approaches as means to provide input data for biomechanical models applied to understand functional transitions in the fossil record, and perhaps even in taxon-rich statistical models that examine broad-scale macroevolutionary patterns. We suggest that future work should go back to the bones to test if correlations between attachment area and muscle size within homologous muscles across a large number of species yield strong predictive relationships that could be used to deliver more accurate predictions for macroevolutionary and functional studies. 相似文献
74.
The influence of buffer/capping-layer-mediated stress on the coercivity of NdFeB films is demonstrated. NdFeB films, 5 μm thick and rich in Nd, were deposited on Si/SiO2 and Al2O3 substrates, with or without buffer/capping layers of Ta. The coercivity of Ta-free samples (~0.5 T) is significantly less than that achieved in samples with Ta present as a buffer and/or capping layer (1.7–1.8 T). The as-sputtered Ta layers are under strong compressive stress due to peening. During post-deposition annealing to crystallize the Nd2Fe14B phase, stresses are relieved in the Ta layer. This leads in turn to a compressive stress in the NdFeB layer, inducing extrusion of a Nd-rich phase up through the NdFeB layer. The high values of coercivity achieved in Ta-containing structures are attributed to good coverage of individual Nd2Fe14B grains with the redistributed Nd-rich phase. 相似文献
75.
The performance of a particulate-biofilm, expanded-bed process for nitrification of activated sludge final effluent (ASFE) is reported for a plant receiving mixed industrial and domestic wastewater. The support material for the particulate-biofilms was glassy coke, to which the nitrifying bacteria attached and formed a highly active biofilm. An average nitrification rate of 1.7+/-0.6 kg m(expanded bed)(-3)d(-1) was recorded during operation of the bioreactor, which had a hydraulic residence time of 15 min. On average, the ASFE contained 12.6+/-3.7 g m(-3) NH3-N, which was reduced to 2.6+/-3.3 g m(-3) NH3-N. Furthermore, transfer of 10-12% of the oxygen in air was achieved using counter-current aeration. This investigation has demonstrated that a high rate of nitrification can be achieved with a particulate-biofilm, expanded-bed process. It has also demonstrated that the process can operate without backwashing and still remove particulate material from the ASFE feed. 相似文献
76.
F. Max Yavitt Tobin E. Brown Ella A. Hushka Monica E. Brown Nikolche Gjorevski Peter J. Dempsey Matthias P. Lutolf Kristi S. Anseth 《Advanced materials (Deerfield Beach, Fla.)》2020,32(30):1905366
Intestinal organoids are useful in vitro models for basic and translational studies aimed at understanding and treating disease. However, their routine culture relies on animal-derived matrices that limit translation to clinical applications. In fact, there are few fully defined, synthetic hydrogel systems that allow for the expansion of intestinal organoids. Here, an allyl sulfide photodegradable hydrogel is presented, achieving rapid degradation through radical addition-fragmentation chain transfer (AFCT) reactions, to support routine passaging of intestinal organoids. Shear rheology to first characterize the effect of thiol and allyl sulfide crosslink structures on degradation kinetics is used. Irradiation with 365 nm light (5 mW cm−2) in the presence of a soluble thiol (glutathione at 15 × 10−3 m ), and a photoinitiator (lithium phenyl-2,4,6-trimethylbenzoylphosphinate at 1 × 10−3 m ), leads to complete hydrogel degradation in less than 15 s. Allyl sulfide hydrogels are used to support the formation of epithelial colonies from single intestinal stem cells, and rapid photodegradation is used to achieve repetitive passaging of stem cell colonies without loss in morphology or organoid formation potential. This platform could support long-term culture of intestinal organoids, potentially replacing the need for animal-derived matrices, while also allowing systematic variations to the hydrogel properties tailored for the organoid of interest. 相似文献
77.
An experiment was conducted to develop models to predict oxygen consumption of males and females engaged in common materials handling tasks including lifting, lowering, pushing, pulling, (de)palletising and combination tasks involving lifting or lowering a box and carrying it a set distance and lifting or lowering it to the destination. Nineteen male and 19 female subjects participated in the study. A psychophysical approach was used to set load limits for individual subjects for the oxygen consumption protocol. The 8398 oxygen consumption values collected were entered into the initial regression analyses and 168 potential outliers were removed before the final models were run. In addition to relevant task variables, body weight was a significant predictor variable in all models. The r(2) values for the final models ranged from 0.54 to 0.82 and the root mean square errors ranged from 90.2 ml to 294.8 ml. 相似文献
78.
A relatively neglected topic in manual materials handling (MMH) research is the impact of the accuracy of task parameter measurements on the application of various assessment methods. A laboratory experiment was conducted to investigate the accuracy of NIOSH equation parameter measurements made by eight subjects following a 4-h training session. Five individual tasks were measured; two were single tasks and three were part of a multiple-component simulated palletizing operation. Significant differences between reference parameter measurements and average measurements made by subjects were found. The sensitivity analysis showed that frequency and horizontal location are the most important parameters. These parameters also tended to have the highest measurement errors. Recommendations for increasing the effectiveness of training programs for NIOSH equation users based on the results of the study are presented. 相似文献
79.
80.
PA Farley CL Dempsey AA Shillington C Kulis-Robitaille K Colgan G Bernstein 《Canadian Metallurgical Quarterly》1997,54(21):2478-2482
Patient functional status after administration of either granisetron or ondansetron to prevent acute chemotherapy-induced nausea and vomiting (CINV) was studied. Pharmacists and nurses from six cancer centers distributed Functional Living Index-Emesis (FLIE) questionnaires to 115 outpatients receiving either granisetron or ondansetron for prevention of CINV. The emetogenic potential of each patient's chemotherapy regimen was high, moderately high, or moderate. Immediately before and 72 hours after chemotherapy, each patient rated his or her reaction to each of 18 items on the questionnaire on a 7-point scale. Possible scores ranged from 18 to 126, with higher scores indicating higher levels of functioning. The occurrence of nausea in the granisetron group was 40.0% compared with 43.2% in the ondansetron group; the occurrence of vomiting was 18.8% in the granisetron group and 11.1% in the ondansetron group. Patients who received highly emetogenic chemotherapy had significantly lower scores on the FLIE after chemotherapy than before. Patients with both nausea and vomiting reported a much higher negative impact on functional status after chemotherapy than those with nausea only. The mean prechemotherapy and postchemotherapy FLIE scores were 124.2 and 110.4 for granisetron and 124.9 and 111.9 for ondansetron. Granisetron and ondansetron did not differ significantly in their effect on functional status reported by patients before and 72 hours after receiving cancer chemotherapy. 相似文献