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1.
The specific heat of 4He condensed on an evaporated gold surface has been measured for coverages between 0.007 and 0.096 Å?2 and temperatures between 0.4 and 3.0 K. There are at least two types of physisorption site on the gold surface with binding energies ?83 ± 7 and ?94 ± 7 K. For coverages below 0.06 Å?2 (~0.5 monolayers), the 4He is a two-dimensional classical gas at sufficiently high temperatures. At lower temperatures and higher coverages, the 4He forms condensed phases, including liquids, solids commensurate with the gold lattice, and incommensurate solids. The phase diagram of 4He/evaporated gold is similar to that for 4He/graphite, but the phase boundaries are shifted and not well defined, nor is the diagram as rich in structure.  相似文献   
2.
The University of Michigan Digital Library (UMDL) is designed as an open system that allows third parties to build and integrate their own profit-seeking agents into the marketplace of information goods and services. The profit-seeking behavior of agents, however, risks inefficient allocation of goods and services, as agents take strategic stances that might backfire. While it would be good if we could impose mechanisms to remove incentives for strategic reasoning, this is not possible in the UMDL. Therefore, our approach has instead been to study whether encouraging the other extreme—making strategic reasoning ubiquitous—provides an answer.Toward this end, we have designed a strategy (called the p-strategy) that uses a stochastic model of the market to find the best offer price. We have then examined the collective behavior of p-strategy agents in the UMDL auction. Our experiments show that strategic thinking is not always beneficial and that the advantage of being strategic decreases with the arrival of equally strategic agents. Furthermore, a simpler strategy can be as effective when enough other agents use the p-strategy. Consequently, we expect the UMDL is likely to evolve to a point where some agents use simpler strategies and some use the p-strategy.  相似文献   
3.
Food allergies affect 6 to 8% of children and 2% of adults in the United States. For reasons that are not clear, eight types of food account for a vast majority (approximately 90%) of food-induced hypersensitivity reactions. In this study, C57Bl/6 mice were used to test the hypothesis that commonly allergenic foods are intrinsically more immunogenic than rarely allergenic or nonallergenic foods in allergy-susceptible hosts. Groups of mice (n = 4 to 5) were injected intraperitoneally with the protein extracts (plus alum as an adjuvant) from chicken eggs, peanuts, almonds, filberts-hazelnuts, walnuts, soybeans, and wheat (commonly allergenic foods) and coffee, sweet potatoes, carrots, white potatoes, cherries, lettuce, and spinach (rarely allergenic and nonallergenic foods). Primary and secondary immune responses (as measured by specific IgG1 antibody serum levels) were measured by an enzyme-linked immunosorbent assay. Proteins from peanuts, almonds, filberts, sweet potatoes, cherries, and spinach elicited robust primary and/or secondary immune responses. Proteins from eggs, walnuts, and lettuce elicited poor primary responses but significant secondary responses. In contrast, wheat, soybeans, coffee, carrots, and white potatoes elicited barely detectable to poor primary and secondary immune responses. The order of the immunogenicity levels of these foods in mice is as follows: almonds = filberts > spinach (Rubisco) > peanuts > or = sweet potatoes > cherries > lettuce > walnuts > chicken eggs > carrots > or = white potatoes > wheat = coffee = soybeans. In summary, these data demonstrate for the first time that: (i) foods vary widely with regard to their relative immunogenicity in allergy-susceptible hosts and (ii) intrinsic immunogenicity in mice does not distinguish commonly allergenic foods from rarely allergenic or nonallergenic foods.  相似文献   
4.
This paper reviews some of the ways cryogenics can help solve the energy crisis.Five specific areas are covered: the use of LNG, the conversion of coal to fuel gas using oxygen from air separation plants, the use of superconductors in power plants and electrical transmission lines, superconducting instruments for geophysical exploration of new energy resources, and the Hydrogen Economy.  相似文献   
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Oxidized low density lipoprotein (LDL) and acetyl LDL are recognized by the scavenger receptor class A type I/II (SR-AI/II) on macrophages and liver endothelial cells. Several investigators have suggested that there are additional receptors specific for oxidized LDL, but characterization of these alternate receptors for oxidized LDL and evaluation of their quantitative importance in uptake of oxidized LDL has been difficult because of overlapping ligand specificity with SR-AI/II. The purpose of this study was to determine the importance of SR-AI/II in the removal of modified LDL from the bloodstream in vivo. The clearance rate of oxidized LDL from plasma in normal mice was very rapid, and > 90% of injected dose was removed from the blood within 5 min. Clearance rates of oxidized LDL were equally high in SR-AI/II knockout mice, indicating that this receptor is not required for removal of oxidized LDL from plasma. Surprisingly, there was no difference in the clearance rate of acetyl LDL in wild-type and SR-AI/II knockout animals. The plasma clearance of radioiodinated acetyl LDL was almost fully blocked by a 50-fold excess of unlabeled acetyl LDL, but the latter only inhibited oxidized LDL clearance by approximately 5%. Both modified LDLs were cleared mostly by the liver, and there was no difference in the tissue distribution of modified LDL in control and knockout mice. Studies in isolated nonparenchymal liver cells showed that Kupffer cells accounted for most of the uptake of oxidized LDL. Extensively oxidized LDL and LDL modified by exposure to fatty acid peroxidation products were efficient competitors for the uptake of labeled oxidized LDL by SR-AI/II-deficient Kupffer cells, while acetyl LDL and malondialdehyde-modified LDL were relatively poor competitors.  相似文献   
7.
The primary objective of the present study was to compare the effect of a neoprene sleeve on knee joint position sense during a sitting open kinetic chain test and a supine closed kinetic chain test. Young (24 +/- 2 years old), healthy subjects (18 men and 18 women) performed knee joint angle replication tests during open kinetic chain knee extension (sitting) and closed kinetic chain leg press (supine with an axial load of 15% body weight) before and after application of a neoprene sleeve over the dominant knee. The improvement in ability to replicate joint angles after application of the sleeve (sleeve effect) was significantly less during the supine closed kinetic chain test (0.3 degree +/- 1.4 degrees) than during the sitting open kinetic chain test (1.2 degrees +/- 1.1 degrees). The sleeve effect was inversely related to subjects' performance without the sleeve during both the sitting open kinetic chain and supine closed kinetic chain tests, suggesting that some people may derive greater benefit from the sleeve than others. Although the sleeve effects were small, particularly during the supine closed kinetic chain test, 72% of subjects felt that the sleeve improved their overall test performance. Future research is needed to establish the functional relevance of the small sleeve effects observed and to identify the characteristics of people who might derive greatest benefit from sleeve use.  相似文献   
8.
OBJECTIVE: To define the prevalence of mental disorder and need for psychiatric treatment in new remand prisoners and to determine to what extent these are recognised and addressed in prison. DESIGN: Study of consecutive male remand prisoners at reception using a semistructured psychiatric interview. SETTING: Large remand prison for men (HMP Durham). SUBJECTS: 669 men aged 21 years and over on remand, awaiting trial. MAIN OUTCOME MEASURES: Prevalence of mental disorder at reception, prisoners need for psychiatric treatment, identification of mental disorder by prison reception screening, and numbers placed appropriately in the prison hospital. RESULTS: 148 (26%) men had one or more current mental disorders (excluding substance misuse) including 24 who were acutely psychotic. The prison reception screening identified 34 of the men with mental disorder and six of those with acute psychosis. 168 men required psychiatric treatment, 50 of whom required urgent intervention; 16 required immediate transfer to psychiatric hospital. Of these 50, 17 were placed on the hospital wing because of mental disorder recognised at prison screening. CONCLUSION: Not only is the prevalence of mental disorder, in particular severe mental illness, high in this population, but the numbers identified at reception are low and subsequent management in prison is poor.  相似文献   
9.
DIDS: rapidly prototyping configuration design systems   总被引:3,自引:0,他引:3  
The domain independent design system (DIDS) provides a set of tools for rapidly constructing new configuration design systems from a library of reusable software elements called mechanisms. A DIDS user begins by creating a model of the problem domain and the task to be automated. This includes describing a library of parts from which new artifacts could be configured, optimization and preference criteria, and functionality constraints. DIDS analyzes this input and automatically builds an operational prototype system by selecting and combining mechanisms. DIDS' ability to automate this process is derived from its model of configuration design, which enables reusable mechanisms to be identified and automatically selected based on a problem's characteristics. The use of DIDS is illustrated by showing how DIDS solved an elevator-configuration problem.  相似文献   
10.
Managed care and escalating healthcare costs have affected all aspects of clinical practice. Today's practitioners must evaluate each patient and clinical situation to select the appropriate intravenous delivery venue to improve the chances of producing a satisfactory outcome. The IV venue discussed in this article will focus on the key elements of identifying patients who will benefit from receiving pharmacomedical services in a home infusion therapy program.  相似文献   
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