全文获取类型
收费全文 | 1458篇 |
免费 | 106篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 3篇 |
化学工业 | 398篇 |
金属工艺 | 12篇 |
机械仪表 | 13篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 44篇 |
轻工业 | 595篇 |
水利工程 | 7篇 |
石油天然气 | 7篇 |
无线电 | 52篇 |
一般工业技术 | 171篇 |
冶金工业 | 116篇 |
原子能技术 | 4篇 |
自动化技术 | 112篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 54篇 |
2021年 | 56篇 |
2020年 | 28篇 |
2019年 | 23篇 |
2018年 | 47篇 |
2017年 | 44篇 |
2016年 | 58篇 |
2015年 | 46篇 |
2014年 | 59篇 |
2013年 | 76篇 |
2012年 | 101篇 |
2011年 | 105篇 |
2010年 | 72篇 |
2009年 | 74篇 |
2008年 | 86篇 |
2007年 | 66篇 |
2006年 | 70篇 |
2005年 | 64篇 |
2004年 | 51篇 |
2003年 | 46篇 |
2002年 | 35篇 |
2001年 | 21篇 |
2000年 | 18篇 |
1999年 | 22篇 |
1998年 | 49篇 |
1997年 | 31篇 |
1996年 | 35篇 |
1995年 | 24篇 |
1994年 | 17篇 |
1993年 | 20篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有1565条查询结果,搜索用时 15 毫秒
21.
Elsa Corts-Montero María Rodríguez-Muoz M. Carmen Ruiz-Cantero Enrique J. Cobos Pilar Snchez-Blzquez Javier Garzn-Nio 《International journal of molecular sciences》2021,22(1)
Transient receptor potential ankyrin member 1 (TRPA1) belongs to the family of thermo TRP cation channels that detect harmful temperatures, acids and numerous chemical pollutants. TRPA1 is expressed in nervous tissue, where it participates in the genesis of nociceptive signals in response to noxious stimuli and mediates mechanical hyperalgesia and allodynia associated with different neuropathies. The glutamate N-methyl-d-aspartate receptor (NMDAR), which plays a relevant role in allodynia to mechanical stimuli, is connected via histidine triad nucleotide-binding protein 1 (HINT1) and type 1 sigma receptor (σ1R) to mu-opioid receptors (MORs), which mediate the most potent pain relief. Notably, neuropathic pain causes a reduction in MOR antinociceptive efficacy, which can be reversed by blocking spinal NMDARs and TRPA1 channels. Thus, we studied whether TRPA1 channels form complexes with MORs and NMDARs that may be implicated in the aforementioned nociceptive signals. Our data suggest that TRPA1 channels functionally associate with MORs, delta opioid receptors and NMDARs in the dorsal root ganglia, the spinal cord and brain areas. These associations were altered in response to pharmacological interventions and the induction of inflammatory and also neuropathic pain. The MOR-TRPA1 and NMDAR-TRPA1 associations do not require HINT1 or σ1R but appear to be mediated by calcium-activated calmodulin. Thus, TRPA1 channels may associate with NMDARs to promote ascending acute and chronic pain signals and to control MOR antinociception. 相似文献
22.
Dragan Jocic Susana Vílchez Tatjana Topalovic Ricardo Molina Antonio Navarro Petar Jovancic Maria Rosa Juli Pilar Erra 《应用聚合物科学杂志》2005,97(6):2204-2214
This study examines in detail the influence of low‐temperature plasma and biopolymer chitosan treatments on wool dyeability. Wool knitted fabrics were treated and characterized by whiteness and shrink‐resistance measurements. Surface modification was assessed by contact‐angle measurements of human hair fibers, which were used as a model to study the wetting properties of the treated wool knitted fabrics. The dyeing behavior was assessed from the diffusion mechanism point of view. The dyeing kinetics were measured at two different pHs (4.2 and 6.5) and three different temperatures (60, 85, and 100°C) to gain information about the contribution of the surface modification treatment to the dyeing mechanism. The exhaustion and reflectance data were compared, and the apparent diffusion coefficients were calculated. On the basis of the obtained results, a model for the dyeing mechanism of the chitosan treated wool was proposed. When treated with chitosan, the polymer sheath spread on the surface of the fibers acted as a predominant dyeing site in very short dyeing times, thus interacting with the dye and in later stages imparting the dye to the wool fiber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2204–2214, 2005 相似文献
23.
E. Herrero N. Carmona J. Llopis M.A. Villegas 《Journal of the European Ceramic Society》2007,27(16):4589-4594
New sol–gel based sensitive materials able to detect moderate doses of UV, Vis and near IR radiations have been designed, prepared and characterised. These glasslike detectors are respectively composed by four different sols of inorganic and hybrid organic–inorganic silica matrixes. The sols were prepared from alkoxide (TEOS) and alkylalkoxide (GLYMO) precursors with molar ratios 1:0, 1:1, 1:4 and 0:1, respectively. All the sols were doped with an organic photochromic dye (spiropyran). The detectors characterisation was carried out by means of exposures to natural light under different light intensities (100–3000 lx). The highest sensitivity against the light radiation was found for sols with molar ratio TEOS:GLYMO of 1:1. The time response of detectors is found at about 10 min and their life time is roughly 4 months at least. Moreover, the detectors show good optical reversibility. These sensitive glasslike materials have been designed to be applied for preservation of historical goods. They can detect and evaluate dangerous light doses for the proper conservation conditions of historical materials, which are sensitive or moderately sensitive against light radiation (<600 lx). 相似文献
24.
Juan Pedro Muñoz-Gea Josemaria Malgosa-Sanahuja Pilar Manzanares-Lopez 《Peer-to-Peer Networking and Applications》2013,6(3):340-360
Recently, a new peer-assisted architecture to build content delivery systems has been presented. This architecture is based on the use of the storage capacity of end-users’ set-top boxes (STBs), connected in a peer-to-peer (P2P) manner in order to help the content servers in the delivery process. In these systems, the contents are usually split into a set of smaller pieces, called sub-streams, which are randomly injected at the STBs. The present paper is focused on Video on Demand (VoD) streaming and it is assumed that the STB-based content delivery system is deployed over the global Internet, where the clients are distributed over different ISP networks. In this scenario, three different strategies are studied for increasing the percentage of data uploaded by peers, in order to offload the content servers as much as possible. First of all, a new mechanism is presented which determines which sub-stream has to be placed at which STB by a Non-Linear Programming (NLP) formulation. A different strategy for reducing the content server load is to take advantage of the available bandwidth in the different ISP networks. In this sense, two new mechanisms for forwarding the VoD requests to different ISP networks are presented. Finally, the present paper also shows that in some situations the available uplink bandwidth is associated with STBs that do not have the required sub-streams. Regarding this concern, a new mechanism has been designed that dynamically re-allocates some streams, which are being transmitted from specific STBs, to different STBs, in order to find the necessary resources to start new streaming sessions. 相似文献
25.
A new graphical visualization of n-dimensional Pareto front for decision-making in multiobjective optimization 总被引:1,自引:0,他引:1
New challenges in engineering design lead to multiobjective (multicriteria) problems. In this context, the Pareto front supplies a set of solutions where the designer (decision-maker) has to look for the best choice according to his preferences. Visualization techniques often play a key role in helping decision-makers, but they have important restrictions for more than two-dimensional Pareto fronts. In this work, a new graphical representation, called Level Diagrams, for n-dimensional Pareto front analysis is proposed. Level Diagrams consists of representing each objective and design parameter on separate diagrams. This new technique is based on two key points: classification of Pareto front points according to their proximity to ideal points measured with a specific norm of normalized objectives (several norms can be used); and synchronization of objective and parameter diagrams. Some of the new possibilities for analyzing Pareto fronts are shown. Additionally, in order to introduce designer preferences, Level Diagrams can be coloured, so establishing a visual representation of preferences that can help the decision-maker. Finally, an example of a robust control design is presented - a benchmark proposed at the American Control Conference. This design is set as a six-dimensional multiobjective problem. 相似文献
26.
Virpi Oksman Ville Ollikainen Elina Noppari Carlos Herrero Antti Tammela 《Multimedia Systems》2008,14(2):105-114
Recently, mobile TV has been launched in several countries. While mobile TV integrates television contents into mobile phones,
the most personal of communication devices, it becomes interesting to know how this feature will be used throughout the day
and in varying contexts of everyday life. This paper presents empirical results on the use of mobile TV with different delivery
mechanisms and both quantitative and qualitative results on how end-users prefer to use mobile TV contents in different situations.
The data is based on ongoing empirical research in Finland in 2006 and 2007. The mobile TV services under study included both
news and entertainment contents, and were tested in 3G, DVB-H and Wi-Fi networks using different delivery paradigms: broadcast,
on-demand and download. To explore the use of different delivery methods and content consumption, we have developed a mobile
TV service protoype, called Podracing. The analysis shows that users appreciated up-to-date information and information-rich
media forms and contents especially for mobile news delivery. There was high demand for only the latest news on mobiles. The
real-time property was considered important. Most of the users looked at the headlines or followed the news several times
a day – much more often than the traditional TV and news prime times would allow. 相似文献
27.
Herrero J.G. Berlanga A. Lopez J.M.M. 《Evolutionary Computation, IEEE Transactions on》2009,13(1):151-168
This paper addresses a real-world engineering design requiring the application of effective and global optimization techniques. The problem it deals with is the design of nonlinear tracking filters under up to several hundreds of performance specifications. The suitability of different evolutionary computation techniques for solving multiobjective problems is explored, contrasting the performance achieved with recent multiobjective evolutionary algorithm (MOEAs) proposals and different aggregation schemes. In particular, a new scheme is proposed to build a fitness function based on an operator that selects worst cases of multiple specifications in different situations. They have been evaluated in the design of an air traffic control (ATC) tracking filter that should accomplish a specific normative with 264 specifications. Results show their performance in terms of effectiveness and computational load, comparing their capability to scale the problem with respect to problem size. 相似文献
28.
In today's highly interconnected, uncertain and dynamic business environment, team boundary spanning has become an important determinant of the performance of new product development (NPD) projects. Despite the positive evidence supporting the use of boundary spanning activities by NPD teams, little is still known about how boundary spanning teams become high-performance teams. The current study advances research on this subject by examining the mediating effect of team potency on the relationship between team boundary spanning and new product performance, as well as the moderating effects of team size and functional diversity on the relationship between team boundary spanning and team potency. Data from a time-lagged survey study of 140 NPD projects found that team boundary spanning can promote team potency that, in turn, results in greater new product quality and new product creativity. The positive effect of team boundary spanning on team potency was found to be more pronounced for NPD teams of medium size and high levels of functional diversity. 相似文献
29.
30.
Shen Lang Poudel Nirakar Gibson George N. Hou Bingya Chen Jihan Shi Haotian Guignon Ernest Page William D. Pilar Arturo Cronin Stephen B. 《Nano Research》2018,11(4):2310-2314
Nano Research - We report plasmon resonant excitation of hot electrons in a photodetector based on a metal/oxide/metal (Au/Al2O3/graphene) heterostructure. In this device, hot electrons, excited... 相似文献