全文获取类型
收费全文 | 328篇 |
免费 | 15篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 52篇 |
金属工艺 | 15篇 |
机械仪表 | 8篇 |
建筑科学 | 28篇 |
能源动力 | 37篇 |
轻工业 | 17篇 |
石油天然气 | 3篇 |
无线电 | 27篇 |
一般工业技术 | 96篇 |
冶金工业 | 21篇 |
原子能技术 | 3篇 |
自动化技术 | 33篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 27篇 |
2011年 | 23篇 |
2010年 | 22篇 |
2009年 | 30篇 |
2008年 | 34篇 |
2007年 | 22篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 14篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有343条查询结果,搜索用时 15 毫秒
51.
A Comparison of Leisure Time Spent in a Garden with Leisure Time Spent Indoors: On Measures of Restoration in Residents in Geriatric Care 总被引:2,自引:0,他引:2
During the past 20 years, findings have indicated that nature plays an active role in helping people recover from stress and fatigue. Two of the most cited theories in this field are Rachel and Stephen Kaplan's theory of recovery from Directed Attention Fatigue in nature and Roger Ulrich's theory of aesthetic and affective responses to natural environments and stress recovery. One aim of the present study is to test whether being outdoors in a green recreational environment causes people to be more focused, compared to being in a room indoors (in line with hypotheses suggested by the Kaplans). Another aim is to test whether people experience stress reduction, i.e. as evidenced by changes in blood pressure and heart rate, if they are placed in an environment with many green elements (in line with hypotheses suggested by Ulrich). The overall study design is that of an intervention study. Fifteen elderly persons living at a home for very elderly people participated. Their powers of concentration, blood pressure and heart rate were measured before and after an hour of rest in a garden or in an indoor setting. Seven elderly people were randomly chosen to have their first series of tests in a garden, while eight elderly people had their first series of tests indoors. The results indicate that powers of concentration increase for very elderly people after a visit to a garden outside the geriatric home in which they live, compared to that after resting indoors in their favourite room. The results did not show any effects on blood pressure or heart rate. It is suggested that having a one-hour rest outdoors in a garden setting plays a role in elderly people's powers of concentration, and could thereby affect their performance of activities of daily living. One important factor in this study was that both the outdoor environment and the indoor environment at the home were highly valued by participants. 相似文献
52.
The present work presents methodology and development of a mathematical model for prediction of the influence of oxide scale on heat transfer during reheating of steel in an industrial furnace. In this developed model, temperatures inside the steel billet were measured and with thermocouples at selected places and were collected by a water cooled computer that was traveling inside the slab. CFD is used to calculate the flow field inside of a furnace. The mass‐transfer coefficient of the scale formation is obtained by solving the convection mass‐diffusion equation across a boundary layer to the surface of a flat plate. A model for inverse heat conduction is employed to calculate the local surface temperature and heat flux on top of the growing oxide scale layer on a slab moving through a walking beam reheating furnace. By using the inverse method, the transient temperature and heat flux was firstly determined on the surface of the steel. During subsequent computations, the growth of the scale was calculated and the surface temperature of the oxide scale was extracted by using the Cauchy data from the previous calculations. The sensibility of the model on steel physical parameters is studied, and suitable parameters were obtained for heating a low carbon steel plate in the reheating furnace. Results show that the oxide scale layer should not be neglected in reheating models. 相似文献
53.
Compatibilizing effects of ethylene/propylene (EPR) diblock copolymers on the morphology and mechanical properties of immiscible blends produced from recycled low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) with 20 wt.‐% of recycled poly(propylene) (PP) were investigated. Two different EPR block copolymers which differ in ethylene monomer unit content were applied to act as interfacial agents. The morphology of the studied blends was observed by scanning‐ (SEM) and transmission electron microscopy (TEM). It was found that both EPR copolymers were efficient in reducing the size of the dispersed phase and improving adhesion between PE and PP phases. Addition of 10 wt.‐% of EPR caused the formation of the interfacial layer surrounding dispersed PP particles with the occurrence of PE‐LD lamellae interpenetration into the layer. Tensile properties (elongation at yield, yield stress, elongation at break, Young's modulus) and notched impact strength were measured as a function of blend composition and chemical structure of EPR. It was found that the EPR with a higher content of ethylene monomer units was a more efficient compatibilizer, especially for the modification of PE‐LD/PP 80/20 blend. Notched impact strength and ductility were greatly improved due to the morphological changes and increased interfacial adhesion as a result of the EPR localization between the phases. No significant improvements of mechanical properties for recycled PE‐HD/PP 80/20 blend were observed by the addition of selected block copolymers. 相似文献
54.
Olurotimi Richard Akinlofa Patrik O'Brian Holt Eyad Elyan 《International journal of human-computer interaction》2014,30(3):250-265
Cognitive computational modeling is a viable methodology for further investigation of the hitherto inconclusive findings on the cognitive benefits of dynamic versus static visualization components of instructions. This is more so as contemporary cognitive architectures such as the Adaptive Control of Thought–Rational (ACT–R) 6.0 are increasingly applied to traditional cognitive psychology research problems. The application of this methodology is, however, restricted by the limited capability of existing architectures for implementing detailed atomic motor actions such as those involved in complex skill acquisition and performance. This article presents a 2-component computational modeling methodology for investigating the cognitive processes involved in the acquisition and performance of skilled motor tasks. The approach specifies a novel combination of a sequence-of-point technique with a movement control mechanism to implement variously acquired cognitive mental task representations and their intertwined role in postlearning performance as evident in the atomic control of motor actions. This paradigm is validated for 2 experiments using incrementally developed cognitive models developed in ACT–R 6.0. The model's quantitative outputs correlate significantly with equivalent empirical human data. This has implications for multimedia instructional design, especially where rapid, transferrable skill acquisition is desired on initial exposure. 相似文献
55.
56.
Patrik?LambertEmail author Adrià?De?Gispert Rafael?Banchs José?B.?Mari?o 《Language Resources and Evaluation》2005,39(4):267-285
The purpose of this paper is to provide guidelines for building a word alignment evaluation scheme. The notion of word alignment quality depends on the application: here we review standard scoring metrics for full text alignment and give explanations on how to use them better. We discuss strategies to build a reference corpus, and show that the ratio between ambiguous and unambiguous links in the reference has a great impact on scores measured with these metrics. In particular, automatically computed alignments with higher precision or higher recall can be favoured depending on the value of this ratio. Finally, we suggest a strategy to build a reference corpus particularly adapted to applications where recall plays a significant role, like in machine translation. The manually aligned corpus we built for the Spanish-English European Parliament corpus is also described. This corpus is freely available. 相似文献
57.
The development of low-cost, accurate, and equipment-free diagnostic tests is crucial to many clinical, laboratory, and field applications, including forensics and medical diagnostics. Cellulose fiber-based paper is an inexpensive, biodegradable, and renewable resource, the use of which as a biomolecule detection matrix and support confers several advantages compared to traditional materials such as glass. In this context, a new, facile method for the preparation of surface functionalized papers bearing single-stranded probe DNA (ssDNA) for rapid target hybridization via capillary transport is presented. Optimized reaction conditions were developed that allowed the direct, one-step activation of standard laboratory filters by the inexpensive and readily available bifunctional linking reagent, 1,4-phenylenediisothiocyanate. Such papers were thus amenable to subsequent coupling of amine-labeled ssDNA under standard conditions widely used for glass-based supports. The intrinsic wicking ability of the paper matrix facilitated rapid sample elution through arrays of probe DNA, leading to significant, detectable hybridization in the time required for the sample liquid to transit the vertical length of the strip (less than 2 min). The broad applicability of these paper test strips as rapid and specific diagnostics in "real-life" situations was exemplified by the discrimination of amplicons generated from canine and human mitochondrial and genomic DNA in mock forensic samples. 相似文献
58.
Shariatgorji M Källback P Gustavsson L Schintu N Svenningsson P Goodwin RJ Andren PE 《Analytical chemistry》2012,84(10):4603-4607
The limit of detection of low-molecular weight compounds in tissue sections, analyzed by matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), was significantly improved by employing sample washing using a pH-controlled buffer solution. The pH of the washing solutions were set at values whereby the target analytes would have low solubility. Washing the tissue sections in the buffered solution resulted in removal of endogenous soluble ionization-suppressing compounds and salts, while the target compound remained in situ with minor or no delocalization during the buffered washing procedure. Two pharmaceutical compounds (cimetidine and imipramine) and one new protease inhibitor compound were successfully used to evaluate the feasibility of the pH-controlled tissue washing protocol for MALDI-MSI. Enhancement in signal-to-noise ratio was achieved by a factor of up to 10. 相似文献
59.
60.
Indhumati Paramasivam Himendra Jha Ning Liu Patrik Schmuki 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(20):3073-3103
Photocatalytic approaches, that is the reaction of light‐produced charge carriers at a semiconductor surface with their environment, currently attract an extremely wide scientific interest. This is to a large extent due to the high expectations: i) to convert sunlight directly into an energy carrier (H2), ii) to stimulate chemical synthetic reactions, or iii) to degrade unwanted environmental pollutants. Since the early reports in 1972, TiO2 has been the most investigated photocatalytic material by far; this originates from its outstanding electronic properties that allow for a wide range of applications. Not only the material, but also its structure and morphology, can have a considerable influence on the photocatalytic performance of TiO2. In recent years, particularly 1D (or pseudo 1D) structures such as nanowires and nanotubes have received great attention. The present Review focuses on TiO2 nanotube arrays (and similar structures) that grow by self‐organizing electrochemistry (highly aligned) from a Ti metal substrate. Herein, the growth, properties, and applications of these tubes are discussed, as well as ways and means to modify critical tube properties. Common strategies are addressed to improve the performance of photocatalysts such as doping or band‐gap engineering, co‐catalyst decoration, junction formation, or applying external bias. Finally, some unique applications of the ordered tube structures in various photocatalytic approaches are outlined. 相似文献