全文获取类型
收费全文 | 1012篇 |
免费 | 51篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 348篇 |
金属工艺 | 12篇 |
机械仪表 | 14篇 |
建筑科学 | 59篇 |
能源动力 | 15篇 |
轻工业 | 202篇 |
水利工程 | 6篇 |
石油天然气 | 2篇 |
无线电 | 53篇 |
一般工业技术 | 155篇 |
冶金工业 | 59篇 |
原子能技术 | 4篇 |
自动化技术 | 131篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 43篇 |
2021年 | 42篇 |
2020年 | 38篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 26篇 |
2016年 | 31篇 |
2015年 | 31篇 |
2014年 | 42篇 |
2013年 | 72篇 |
2012年 | 64篇 |
2011年 | 70篇 |
2010年 | 66篇 |
2009年 | 60篇 |
2008年 | 57篇 |
2007年 | 55篇 |
2006年 | 49篇 |
2005年 | 51篇 |
2004年 | 35篇 |
2003年 | 22篇 |
2002年 | 25篇 |
2001年 | 11篇 |
2000年 | 22篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 13篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1934年 | 3篇 |
排序方式: 共有1065条查询结果,搜索用时 0 毫秒
961.
An attempt is made to present in a more didactic manner the treatment of the order/disorder transformation expressed in the compound energy formalism. Some statements made in the article by Saunders are analysed and corrected. 相似文献
962.
Vallerand Robert J.; Blais Marc R.; Brière Nathalie M.; Pelletier Luc G. 《Canadian Metallurgical Quarterly》1989,21(3):323
Studied the construction, psychometric properties, and validity of an instrument to measure motivation toward education—the EME. The scale consists of 7 subscales assessing 3 types of internal motivation (to know, to accomplish, and to experience sensations) and 3 types of external motivation (external, introjected, and identified regulation). Human subjects: 746 male and female Canadian adults (mean age 17.62–18.97 yrs) (college students). The EME was administered to 3 groups of students during class time. One group was given the scale twice to determine internal stability. Internal consistency, factorial structure, and construct validity were determined using factorial analysis and the LISREL VI statistical software package (K. G. Joreskog and D. Sorbom, 1984). (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
963.
Råman Vinnå Love Bouffard Damien Wüest Alfred Girardclos Stéphanie Dubois Nathalie 《Water Resources Management》2020,34(13):4133-4146
Water Resources Management - High-resolution lake and reservoir bathymetric surveys can pinpoint locations that may experience underwater landslides (subaquatic sedimentary mass movements). These... 相似文献
964.
965.
Seonho Seok Michel Fryziel Nathalie Rolland Paul-Alain Rolland 《Microsystem Technologies》2012,18(12):2035-2039
This paper presents a Si cap zero-level packaging technique based on a double-layer BCB sealing ring. The BCB ring is defined before the housing cavity etching to achieve high BCB bonding strength. It is found that the non-uniformity of the BCB ring defined on a Si cap with housing cavity prevents the package having high bonding strength. Three different packages have been prepared for shear test; a Si cap without cavity, a recessed Si cap with a conventional BCB ring and a recessed Si cap with pre-defined BCB ring. The three samples for each type of package are measured. The average measured bonding strengths of the test samples are 71, 16 and 42?MPa, respectively, and hence the proposed BCB sealing ring process provides 60?% of bonding strength of Si cap package without cavity for Si cap package with cavity. In addition, the insertion loss change of the packaged CPW is less than 0.1?dB up to 67?GHz while the return loss better than 15?dB at the measured frequency range. 相似文献
966.
We introduce the notion of sofic tree-shifts which corresponds to symbolic dynamical systems of infinite ranked trees accepted by finite tree automata. We show that, contrary to shifts of infinite sequences, there is no unique reduced deterministic irreducible tree automaton accepting an irreducible sofic tree-shift, but that there is a unique synchronized one, called the Fischer automaton of the tree-shift. We define the notion of almost of finite type tree-shift which are sofic tree-shifts accepted by a tree automaton which is both deterministic and co-deterministic with a finite delay. It is a meaningful intermediate dynamical class in between irreducible finite type tree-shifts and irreducible sofic tree-shifts. We characterize the Fischer automaton of an almost of finite type tree-shift and we design an algorithm to check whether a sofic tree-shift is almost of finite type. We prove that the Fischer automaton is a topological conjugacy invariant of the underlying irreducible sofic tree-shift. 相似文献
967.
In many common data analysis scenarios the data elements are logically grouped into sets. Venn and Euler style diagrams are a common visual representation of such set membership where the data elements are represented by labels or glyphs and sets are indicated by boundaries surrounding their members. Generating such diagrams automatically such that set regions do not intersect unless the corresponding sets have a non-empty intersection is a difficult problem. Further, it may be impossible in some cases if regions are required to be continuous and convex. Several approaches exist to draw such set regions using more complex shapes, however, the resulting diagrams can be difficult to interpret. In this paper we present two novel approaches for simplifying a complex collection of intersecting sets into a strict hierarchy that can be more easily automatically arranged and drawn (Figure 1). In the first approach, we use compact rectangular shapes for drawing each set, attempting to improve the readability of the set intersections. In the second approach, we avoid drawing intersecting set regions by duplicating elements belonging to multiple sets. We compared both of our techniques to the traditional non-convex region technique using five readability tasks. Our results show that the compact rectangular shapes technique was often preferred by experimental subjects even though the use of duplications dramatically improves the accuracy and performance time for most of our tasks. In addition to general set representation our techniques are also applicable to visualization of networks with intersecting clusters of nodes. 相似文献
968.
Yohann Luque Eric Kerhervé Nathalie Deltimple Laurent Leyssenne Didier Belot 《国际射频与微波计算机辅助工程杂志》2010,20(6):611-618
This article describes the feasibility of a Power Amplifier (PA) in 0.13 μm CMOS technology from STMicroelectronics for high power applications. To obtain a high output power with a good linearity, a new topology called Stacked Folded Differential Structure (SFDS) is proposed. It allows obtaining similar power performances to a PA with DAT in a lower die area. This PA provides 23 dBm of maximum output power (Pmax) with 20% of power added efficiency (PAE) at 1.95 GHz. The linear gain is equal to 11 dB and the output power at 1 dB compression point (OCP1) achieves 21 dBm. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
969.
We address the problem of designing and planning a multi-period, multi-echelon, multi-commodity logistics network with deterministic demands. This consists of making strategic and tactical decisions: opening, closing or expanding facilities, selecting suppliers and defining the product flows. We use a heuristic approach based on the linear relaxation of the original mixed integer linear problem (MILP). The main idea is to solve a sequence of linear relaxations of the original MILP, and to fix as many binary variables as possible at every iteration. This simple process is coupled with several rounding procedures for some key decision variables. The number of binary decision variables in the resulting MILP is small enough for it to be solved with a solver. The main benefit of this approach is that it provides feasible solutions of good quality within an affordable computation time. 相似文献
970.
Estimating the motion of plant root cells from in vivo confocal laser scanning microscopy images 总被引:1,自引:0,他引:1
Timothy J. Roberts Stephen J. McKenna Cheng-Jin Du Nathalie Wuyts Tracy A. Valentine A. Glyn Bengough 《Machine Vision and Applications》2010,21(6):921-939
Images of cellular structures in growing plant roots acquired using confocal laser scanning microscopy have some unusual properties
that make motion estimation challenging. These include multiple motions, non-Gaussian noise and large regions with little
spatial structure. In this paper, a method for motion estimation is described that uses a robust multi-frame likelihood model
and a technique for estimating uncertainty. An efficient region-based matching approach was used followed by a forward projection
method. Over small timescales the dynamics are simple (approximately locally constant) and the change in appearance small.
Therefore, a constant local velocity model is used and the MAP estimate of the joint probability over a set of frames is recovered.
Occurrences of multiple modes in the posterior are detected, and in the case of a single dominant mode, motion is inferred
using Laplace’e method. The method was applied to several Arabidopsis thaliana root growth sequences with varying levels of success. In addition, comparative results are given for three alternative motion
estimation approaches, the Kanade–Lucas–Tomasi tracker, Black and Anandan’s robust smoothing method, and Markov random field
based methods. 相似文献