全文获取类型
收费全文 | 441篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 83篇 |
金属工艺 | 2篇 |
机械仪表 | 9篇 |
建筑科学 | 26篇 |
矿业工程 | 1篇 |
能源动力 | 6篇 |
轻工业 | 40篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 65篇 |
冶金工业 | 137篇 |
原子能技术 | 2篇 |
自动化技术 | 30篇 |
出版年
2022年 | 5篇 |
2021年 | 4篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 21篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 4篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 13篇 |
1998年 | 43篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 10篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 15篇 |
1975年 | 8篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1971年 | 10篇 |
1969年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有444条查询结果,搜索用时 15 毫秒
31.
The structure of arterial networks is optimized to allow efficient flow delivery to metabolically active tissues. Optimization of flow delivery is a continuous process involving synchronization of the structure and function of the microcirculation with the upstream arterial network. Risk factors for ischemic cardiovascular diseases, such as diabetes mellitus and hyperlipidemia, adversely affect endothelial function, induce capillary regression, and disrupt the micro- to macrocirculation cross-talk. We provide evidence showing that this loss of synchronization reduces arterial collateral network recruitment upon arterial stenosis, and the long-term clinical outcome of current revascularization strategies in these patient cohorts. We describe mechanisms and signals contributing to synchronized growth of micro- and macrocirculation in development and upon ischemic challenges in the adult organism and identify potential therapeutic targets. We conclude that a long-term successful revascularization strategy should aim at both removing obstructions in the proximal part of the arterial tree and restoring “bottom-up” vascular communication. 相似文献
32.
Nguyen Simone P.; McCullough Mary Beth; Noble Ashley 《Canadian Metallurgical Quarterly》2011,103(3):594
The theory–theory account of conceptual development posits that children's concepts are integrated into theories. Concept-learning studies have documented the central role that theories play in children's learning of experimenter-defined categories but have yet to extensively examine complex, real-world concepts, such as health. The present study examined whether providing young children with coherent and causally related information in a theory-based lesson would facilitate their learning about the concept of health. This study used a pretest/lesson/posttest design, plus a 5-month follow-up. Children were randomly assigned to 1 of 3 conditions: theory (i.e., 20 children received a theory-based lesson), nontheory (i.e., 20 children received a nontheory-based lesson), and control (i.e., 20 children received no lesson). Overall, the results showed that children in the theory condition had a more accurate conception of health than children in the nontheory and control conditions, suggesting the importance of theories in children's learning of complex, real-world concepts. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
33.
文章根据对大学生的人格发展状况的调查,分析了大学生人格发展成因,并针对大学生健康人格的培养目标和不同年级大学生的人格特点,论述了培养大学生健康人格的有效途径. 相似文献
34.
Noble RE 《The Science of the total environment》2000,262(1-2):1-3
The uptake of cigarette smoke by a variety of clothing fabrics was determined. The tested fabrics included wool, linen, cotton, silk, rayon, acetate and polyester. While a variety of factors effect such absorption, polyester fabrics were found to significantly take up less smoke than all the other tested cloths. A simple and rapid technique is described for measuring such absorption. 相似文献
35.
Rivastigmine (SDZ ENA 713) is a carbamylating, long-acting reversible and noncompetitive carbamate acetylcholinesterase inhibitor that is indicated as an oral treatment for patients with mild to moderately severe Alzheimer's disease. The drug has been evaluated for this use in 3 well designed, adequately powered, phase II/III, 26-week clinical trials that included a total of 1479 rivastigmine and 647 placebo recipients. Most of these patients had concomitant disorders that were being treated with numerous other drugs. Individual and pooled results of these trials indicate that rivastigmine 6 to 12 mg/day usually produces cognitive, global and functional changes that indicate significantly less deterioration than was observed with placebo in patients with mild to moderately severe Alzheimer's disease. Individual results of the 2 pivotal trials and pooled analysis also show that, compared with placebo recipients, significantly more rivastigmine 6 to 12 mg/day recipients respond to therapy. Indeed, after 26 weeks of therapy in the 2 pivotal trials, significantly more rivastigmine 6 to 12 mg/day than placebo recipients achieved clinically meaningful improvements as defined by 3 separate response criteria. The lower dosage range of 1 to 4 mg/day was not as effective as 6 to 12 mg/day, as measured using these criteria and other efficacy parameters. Rivastigmine causes adverse events that are generally those expected from an acetylcholinesterase inhibitor. They are usually mild to moderate, of short duration and responsive to dosage reduction. Unpublished data from 3989 patients indicate that rivastigmine and placebo were associated with similar incidences of serious adverse events and changes in laboratory parameters, ECG and cardiorespiratory vital signs. The most common events were gastrointestinal, central and peripheral nervous system and whole body adverse events. However, compared with placebo, rivastigmine more commonly caused adverse events resulting in treatment withdrawal. These events were most frequently gastrointestinal and were more common in women. CONCLUSION: Rivastigmine is a useful option for the treatment of patients with mild to moderately severe Alzheimer's disease. Although only short term (6- month) comparisons with placebo are available, given the lack of established treatment options it should be considered for first-line use in this population. 相似文献
36.
37.
Stress corrosion cracking of GRP pultruded rods has been investigated in 0.0001 to 5.0 N hydrochloric acid environments under bending and tensile loading modes. Crack initiation takes place at exposed glass fibres in the surface of the rod, and crack propagation is planar and at right angles to the rod axis. Leaching of calcium and aluminium from the fibres takes place during the cracking process, and time-to-failure is dependent on the acid concentration, the stress level and the ease of access of the acid to the glass fibre surface. Possible mechanisms of crack propagation through the glass fibres and resin are discussed. 相似文献
38.
In this article we continue our exploration of the historical roots of systems biology by considering the work of William Harvey. Central arguments in his work on the movement of the heart and the circulation of the blood can be shown to presage the concepts and methods of integrative systems biology. These include: (a) the analysis of the level of biological organization at which a function (e.g. cardiac rhythm) can be said to occur; (b) the use of quantitative mathematical modelling to generate testable hypotheses and deduce a fundamental physiological principle (the circulation of the blood) and (c) the iterative submission of his predictions to an experimental test. This article is the result of a tri-lingual study: as Harvey’s masterpiece was published in Latin in 1628, we have checked the original edition and compared it with and between the English and French translations, some of which are given as notes to inform the reader of differences in interpretation. 相似文献
39.
Y. Mutoh G. H. Fair B. Noble R. B. Waterhouse 《Fatigue & Fracture of Engineering Materials & Structures》1987,10(4):261-272
Abstract— The crack initiation lives of peened specimens of aluminium alloys 7010 and 8090 are shorter than those of unpeened specimens. This is caused by the acceleration of crack initiation due to stress concentration in the rough peened surface, especially at fold-like defects. The crack growth rate in peened specimens is significantly reduced with increasing Δ K , i.e. with increasing crack length. At a crack length of approximately 0.3 mm this trend is reversed and the crack growth rate rapidly increases and attains the same level of crack growth rate as that in unpeened specimens. The point of smallest crack growth rate roughly corresponds to the point of maximum residual stress. The crack growth rate in a peened specimen has been modelled by assuming the effect of residual stress reduces to the equivalent stress ratio. The predicted results agree well with the experimental data. 相似文献
40.
There is general agreement that the training of decision scientists during the past ten years has left much to be desired. This note presents nine rules relating to the fundamental reasons for the failure of training programs, along with suggestions for improving the present state of affairs. 相似文献