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排序方式: 共有878条查询结果,搜索用时 15 毫秒
71.
Robert G Elkin John C Rogler Thomas W Sullivan 《Journal of the science of food and agriculture》1991,57(4):543-553
White Pekin ducklings were reared in floor pens and given access to nipple-type waterers in order to eliminate a feeding behaviour previously observed in battery brooder-raised ducks in which sorghum tannins were possibly detoxicated by exposure of the ground grain to water. High-tannin sorghum (HTS)—soya bean meal and low-tannin sorghum (LTS)—soya bean meal diets, suboptimal in protein, with or without supplemental methionine, and either in dry mash or pellet form, were fed to both day-old ducks and chicks for either 14 or 17 days, respectively. The chicks were reared in battery brooders. In contrast to previous findings with ducks raised in battery brooders, HTS-fed ducks reared in floor pens exhibited reduced weight gain and feed efficiency values compared with LTS-fed ducks. However, the magnitude of the growth depression caused by feeding ducks HTS versus LTS was much less than that observed in chicks fed the identical diets (17 versus 33%, respectively). Methionine supplementation of the HTS diets completely overcame the reduced weight gain in ducks, but feed efficiency values were still significantly poorer than those of ducks fed methionine-supplemented LTS diets. In contrast, although HTS-fed chicks responded to dietary methionine supplementation, they still exhibited poorer weight gain and feed eficiency values compared with birds fed LTS diets similarly supplemneted. Increasing the dietary level of supplemental methionine did not result in any further improvement in performance of chicks fed either LTS- or HTS-based diets. It was concluded that, compared with chicken, ducks are less affected by dietary sorghum tannins. 相似文献
72.
Nikolas Antzoulatos Elkin Castro Daniele Scrimieri Svetan Ratchev 《Production Engineering》2014,8(6):773-781
Modern manufacturing companies face increased pressures to adapt to shorter product life cycles and the need to reconfigure more frequently their production systems to offer new product variants. This paper proposes a new multi-agent architecture utilising “plug and produce” principles for configuration and reconfiguration of production systems with minimum human intervention. A new decision-making approach for system reconfiguration based on tasks re-allocation is presented using goal driven methods. The application of the proposed architecture is described with a number of architectural views and its deployment is illustrated using a validation scenario implemented on an industrial assembly platform. The proposed methodology provides an innovative application of a multi-agent control environment and architecture with the objective of significantly reducing the time for deployment and ramp-up of small footprint assembly systems. 相似文献
73.
A. A. Chulkina A. I. Ul’yanov V. A. Volkov A. L. Ul’yanov A. V. Zagainov I. A. Elkin 《The Physics of Metals and Metallography》2018,119(3):258-266
Using X-ray, Mössbauer, and magnetic measurements, the formation of phases has been investigated upon mechanosynthesis in a ball planetary mill and upon the subsequent annealing of samples of the cementite composition (Fe0.95–уСr0.05Ni y )75C25, where у = 0–0.20, which contains two alloying elements (chromium and nickel). It has been shown that, in the mechanosynthesis process, cementite alloyed with chromium and a small amount of nickel and an amorphous phase alloyed with chromium and nickel have been formed. Upon heating above 300°С, the amorphous phase is crystallized into nickel-enriched cementite. In the process of annealing at higher temperatures, the most nickel-rich cementite decomposes with the formation of austenite. As a consequence, after annealing at medium temperatures, the composition of the alloys contains cementite alloyed mainly with chromium and some amount of alloyed austenite, which can be found in ferromagnetic or paramagnetic states depending on the Ni content. Annealing at 800°С bring about the complete or partial decomposition of cementite contained in the alloys. The intensity of the decomposition has been determined by the nickel content in the samples. 相似文献
74.
Elaborating novel triacylglyceride (TAG) based polyester hyperbranched unimolecular encapsulating agents represents an original and promising approach to the selective delivery of hydrophobic biologically active compounds. However, selective modification of double bonds in unsaturated TAG to obtain corresponding pure polyhydroxy derivatives with high yields is still a big challenge. Two novel approaches to synthesize the glyceryl tris[9,10-(threo)-dihydroxyoctadecanoate] were proposed and tested: (1) via the bromination and nucleophilic substitution of secondary halide functions by oxyacetyl groups followed by the hydrolysis of acetyls, and (2) direct transformation of the double bonds by the reaction with peroxoformic acid in an excess of formic acid, and the removal of formyl protective groups. Glycerol trioleate and natural olive oil were used as starting materials. The first synthetic route allowed for successful preparation of the corresponding polyhalide and polyoxyacetyl products; however, a more effective final deacetylation procedure is required. The second proposed approach showed a very good reproducibility in obtaining hydroxy-oxyformyl derivatives. The optimal conditions of the reaction involve the use of diethyl ether as a cosolvent and stirring at room temperature for 30 min. To remove the formyl groups, three original procedures using organic solvent medium at room temperature were proposed: in the presence of cesium carbonate in chloroform–methanol mixture, and two methods using hydrochloric acid in chloroform–methanol mixture or in acetone. All three methods were efficient to carry out the deformylation; nevertheless, TAG esters remained stable only with 15–17 % hydrochloric acid in acetone. Simple isolation procedures and high overall yields (95.6 and 94.9 % for both triolein and olive oil, respectively) allow considering the second approach as a promising method to obtain threo-polyhydroxy derivatives from unsaturated TAG. 相似文献
75.
V. M. Strakhov I. V. Surovtseva D. K. Elkin K. S. Elkin A. E. Cherevko 《Coke and Chemistry》2012,55(2):46-49
The industrial use of Kuznetsk Basin SS coal in silicon production is considered. The influence of SS coal quality on the operation of electrothermal furnaces is studied. 相似文献
76.
77.
JS Macpherson J Cummings I Meikle EP Miller JF Smyth 《Canadian Metallurgical Quarterly》1997,33(2):280-283
The effect of the novel topoisomerase I inhibitor NU/ICRF 505 (20 microM, approximate IC50 concentration) on the cell cycle was studied by flow cytometry in four Chinese hamster ovary (CHO) cell lines. Postdrug treated cells were incubated with optimal concentrations of cytochalasin B to prevent re-entry of daughter cells into the cell cycle. NU/ICRF 505 had no significant effect on cell cycle distribution in the parent cell line (CHO-K1) and two mutants hypersensitive to topo II inhibitors (ADR-1, ADR-3), all of which express similar levels of topo I protein. In the drug-resistant variant ADR-r, which overexpresses topo I 2-fold, a significant accumulation of cells in G1 phase was recorded. These results are broadly consistent with the cell cycle effects expected in CHO cells by a classic topo I poison (camptothecin) and add weight to the view that NU/ICRF 505 induces cell death primarily through topo I inhibition. 相似文献
78.
SJ Swanson SJ Mentzer MM DeCamp R Bueno WG Richards EP Ingenito JJ Reilly DJ Sugarbaker 《Canadian Metallurgical Quarterly》1997,185(1):25-32
Three-dimensional (3-D) intravascular ultrasound (IVUS) allows for the visualization of entire coronary segments, provides more detailed insights into the geometry of atherosclerotic plaques and facilitates serial studies. Automated quantitative 3-D IVUS methods reduce the analysis time and the subjectivity of boundary tracing, and permit complex IVUS studies. The 3-D IVUS approach is not restricted to research applications, but may be used as a valuable clinical tool. Evaluation of the coronary segment of interest before catheter-based coronary interventions provides information which may facilitate the selection of interventional devices. Moreover, 3-D IVUS allows for a careful assessment of the procedural results and potential post-procedural complications. ECG-gated image acquisition, automated contour detection, and approaches using data of both 3-D IVUS and biplane angiography represent the recent progress in this field. Three-dimensional IVUS will surely gain further importance and become a routine technique, if the interest and research effort is sustained. 相似文献
79.
A new method for in vivo evaluation of biofilms on surface-modified silicone rubber voice prostheses
EP Everaert HF Mahieu RP Wong Chung GJ Verkerke HC van der Mei HJ Busscher 《Canadian Metallurgical Quarterly》1997,254(6):261-263
A new method is presented that permits a rapid and accurate in vivo evaluation of biofilm formation on surface-modified silicone rubber voice prostheses. The method is based on partial modification of a Groningen button voice prosthesis by exposing half of the prosthesis to an argon plasma. This results in one side of the prosthesis becoming hydrophilic while leaving the unmodified side hydrophobic as a control. Modified prostheses were placed in patients for an evaluation period of approximately 4 weeks. Despite making the silicone rubber surface hydrophilic, biofilm formation was stimulated when compared to unmodified, hydrophobic silicone rubber. Findings show that biofilm formation on voice prostheses is influenced by hydrophobicity of a silicone rubber surface. The method of partial surface modification used was seen to be suitable for demonstrating such influences regardless of nutrition and other variations in the patient's lifestyle. Microbiological analysis of the biofilms on both sides of the prosthesis valve did not show any changes in microbial composition, with Candida albicans, streptococci and staphylococci being the most commonly isolated strains. 相似文献
80.
OBJECTIVE: To study the influence of continuous administration of heparin on platelet function in intensive care patients. DESIGN: Prospective, serial investigation. SETTING: Clinical investigation on a surgical and neurosurgical intensive care unit in a university hospital. PATIENTS: The study included 45 patients: 15 postoperative with patients sepsis (Acute Physiology and Chronic Health Evaluation II score between 15 and 25), 15 trauma patients (Injury Severity Score 15 to 25), and 15 neurosurgical patients. INTERVENTIONS: Management of the patients was carried out according to the guidelines for modern intensive care therapy. Sepsis and trauma patients received standard (unfractionated) heparin continuously [aim: an activated partial thromboplastin time (aPTT) approximately 2.0 times normal value; sepsis-heparin and trauma-heparin patients], whereas neurosurgical patients received no heparin (neurosurgical patients). MEASUREMENTS AND RESULTS: From arterial blood samples, platelet aggregation was measured by the turbidimetric method. Platelet aggregation was induced by adenosine diphosphate (ADP; 2.0 mumol/l), collagen (10 micrograms/ml), and epinephrine (25 mumol/l). Measurements were carried out on the day of diagnosis of sepsis or 12 h after hemodynamic stabilization (trauma and neurosurgery patients) (baseline) and during the next 5 days at 12.00 noon. Standard coagulation parameters [platelet count and fibrinogen and antithrombin III (AT III) plasma concentrations] were also monitored. Heparin 4-10 U/kg per h (mean dose: approximately 500 U/h) was necessary to reach an aPTT of about 2.0 times normal. Platelet count was highest in the neurosurgical patients, but it did not decrease after heparin administration to the trauma and sepsis patients. AT III and fibrinogen plasma levels were similar in the three groups of patients. In the sepsis group, platelet aggregation variables decreased significantly (e.g., epinephrine-induced maximum platelet aggregation:-45 relative % from baseline value). Platelet function recovered during the study and even exceeded baseline values (e.g., ADP-induced maximum platelet aggregation: +42.5 relative % from baseline value). Continuous heparinization did not blunt this increase of platelet aggregation variables. In the heparinized trauma patients, platelet aggregation variables remained almost stable and were no different to platelet aggregation data in the untreated neurosurgical patients. CONCLUSIONS: Continuous administration of heparin with an average dose of approximately 500 U/h did not negatively influence platelet function in the trauma patients. Recovery from reduced platelet function in the sepsis group was not affected by continuous heparinization. Thus, continuous heparinization with this dose appears to be safe with regard to platelet function in the intensive care patient. 相似文献