全文获取类型
收费全文 | 4579篇 |
免费 | 231篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 32篇 |
综合类 | 7篇 |
化学工业 | 1134篇 |
金属工艺 | 62篇 |
机械仪表 | 68篇 |
建筑科学 | 227篇 |
矿业工程 | 3篇 |
能源动力 | 107篇 |
轻工业 | 671篇 |
水利工程 | 40篇 |
石油天然气 | 19篇 |
无线电 | 268篇 |
一般工业技术 | 807篇 |
冶金工业 | 716篇 |
原子能技术 | 12篇 |
自动化技术 | 643篇 |
出版年
2023年 | 37篇 |
2022年 | 103篇 |
2021年 | 169篇 |
2020年 | 76篇 |
2019年 | 111篇 |
2018年 | 129篇 |
2017年 | 109篇 |
2016年 | 140篇 |
2015年 | 113篇 |
2014年 | 178篇 |
2013年 | 288篇 |
2012年 | 227篇 |
2011年 | 316篇 |
2010年 | 225篇 |
2009年 | 210篇 |
2008年 | 223篇 |
2007年 | 204篇 |
2006年 | 200篇 |
2005年 | 136篇 |
2004年 | 144篇 |
2003年 | 128篇 |
2002年 | 108篇 |
2001年 | 74篇 |
2000年 | 74篇 |
1999年 | 67篇 |
1998年 | 59篇 |
1997年 | 58篇 |
1996年 | 66篇 |
1995年 | 64篇 |
1994年 | 57篇 |
1993年 | 51篇 |
1992年 | 52篇 |
1991年 | 45篇 |
1990年 | 62篇 |
1989年 | 40篇 |
1988年 | 48篇 |
1987年 | 35篇 |
1986年 | 39篇 |
1985年 | 41篇 |
1984年 | 45篇 |
1983年 | 29篇 |
1982年 | 42篇 |
1981年 | 20篇 |
1980年 | 23篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1975年 | 16篇 |
1974年 | 15篇 |
排序方式: 共有4816条查询结果,搜索用时 15 毫秒
71.
In this paper we formulate a least squares version of the recently proposed twin support vector machine (TSVM) for binary classification. This formulation leads to extremely simple and fast algorithm for generating binary classifiers based on two non-parallel hyperplanes. Here we attempt to solve two modified primal problems of TSVM, instead of two dual problems usually solved. We show that the solution of the two modified primal problems reduces to solving just two systems of linear equations as opposed to solving two quadratic programming problems along with two systems of linear equations in TSVM. Classification using nonlinear kernel also leads to systems of linear equations. Our experiments on publicly available datasets indicate that the proposed least squares TSVM has comparable classification accuracy to that of TSVM but with considerably lesser computational time. Since linear least squares TSVM can easily handle large datasets, we further went on to investigate its efficiency for text categorization applications. Computational results demonstrate the effectiveness of the proposed method over linear proximal SVM on all the text corpuses considered. 相似文献
72.
Anne Köpsel Päivi Majaranta Poika Isokoski Anke Huckauf 《Behaviour & Information Technology》2016,35(12):1044-1062
Modern interaction techniques like non-intrusive gestures provide means for interacting with distant displays and smart objects without touching them. We were interested in the effects of feedback modality (auditory, haptic or visual) and its combined effect with input modality on user performance and experience in such interactions. Therefore, we conducted two exploratory experiments where numbers were entered, either by gaze or hand, using gestures composed of four stroke elements (up, down, left and right). In Experiment 1, a simple feedback was given on each stroke during the motor action of gesturing: an audible click, a haptic tap or a visual flash. In Experiment 2, a semantic feedback was given on the final gesture: the executed number was spoken, coded by haptic taps or shown as text. With simultaneous simple feedback in Experiment 1, performance with hand input was slower but more accurate than with gaze input. With semantic feedback in Experiment 2, however, hand input was only slower. Effects of feedback modality were of minor importance; nevertheless, semantic haptic feedback in Experiment 2 showed to be useless at least without extensive training. Error patterns differed between both input modes, but again not dependent on feedback modality. Taken together, the results show that in designing gestural systems, choosing a feedback modality can be given a low priority; it can be chosen according to the task, context and user preferences. 相似文献
73.
Satish Shukla Dhananjay Gopal Antonio-Francisco Roldán-López-de-Hierro 《国际通用系统杂志》2016,45(7-8):815-829
Very recently, in order to unify the notions of fuzzy metric space and metric-like space, Shukla and Abbas introduced the concept of fuzzy metric-like space and proved some fixed-point results in this setting. In this article, we modify the notion of Cauchy sequence and completeness to generalize their results. Thus, we extend their theorems to a more general framework, which is also appropriate to generalize some recent, well-known results in this line of research. Furthermore, several examples are presented to illustrate the significance of our results. 相似文献
74.
One has a large computational workload that is “divisible” (its constituent tasks’ granularity can be adjusted arbitrarily) and one has access to p remote computers that can assist in computing the workload. How can one best utilize the computers? Two features complicate this question. First, the remote computers may differ from one another in speed. Second, each remote computer is subject to interruptions of known likelihood that kill all work in progress on it. One wishes to orchestrate sharing the workload with the remote computers in a way that maximizes the expected amount of work completed. We deal with three versions of this problem. The simplest version ignores communication costs but allows computers to differ in speed (a heterogeneous set of computers). The other two versions account for communication costs, first with identical remote computers (a homogeneous set of computers), and then with computers that may differ in speed. We provide exact expressions for the optimal work expectation for all three versions of the problem - via explicit closed-form expressions for the first two versions, and via a recurrence that computes this optimal value for the last, most general version. 相似文献
75.
We study the problem of guaranteeing correct execution semantics in parallel implementations of logic programming languages in presence of built-in constructs that are sensitive to order
of execution. The declarative semantics of logic programming languages permit execution of various goals in any arbitrary
order (including in parallel). However, goals corresponding to extra-logical built-in constructs should respect the sequential
order of execution to ensure correct semantics. Ensuring this correctness in presence of such built-in constructs, while efficiently
exploiting maximum parallelism, is a difficult problem. In this paper, we propose a formalization of this problem in terms
of operations on dynamic trees. This abstraction enables us to: (i) show that existing schemes to handle order-sensitive computations used in current parallel
systems are sub-optimal; (ii) develop a novel, optimal scheme to handle order-sensitive goals that requires only a constant time overhead per operation. While we present our results in the context of logic programming, they will apply equally well to
most parallel non-deterministic systems.
Received: 20 April 1998 / 3 April 2000 相似文献
76.
Researchers have thus far focused on the recognition of alpha and numeric characters in isolation as well as in context. In this paper we introduce a new genre of problems where the input pattern is taken to be a pair of characters. This adds to the complexity of the classification task. The 10 class digit recognition problem is now transformed into a 100 class problem where the classes are {00,…, 99}. Similarly, the alpha character recognition problem is transformed to a 26×26 class problem, where the classes are {AA,…, ZZ}. If lower-case characters are also considered the number of classes increases further. The justification for adding to the complexity of the classification task is described in this paper. There are many applications where the pairs of characters occur naturally as an indivisible unit. Therefore, an approach which recognizes pairs of characters, whether or not they are separable, can lead to superior results. In fact, the holistic method described in this paper outperforms the traditional approaches that are based on segmentation. The correct recognition rate on a set of US state abbreviations and digit pairs, touching in various ways, is above 86%. 相似文献
77.
This paper presents a symbolic formalism for modeling and retrieving video data via the moving objects contained in the video images. The model integrates the representations of individual moving objects in a scene with the time-varying relationships between them by incorporating both the notions of object tracks and temporal sequences of PIRs (projection interval relationships). The model is supported by a set of operations which form the basis of a moving object algebra. This algebra allows one to retrieve scenes and information from scenes by specifying both spatial and temporal properties of the objects involved. It also provides operations to create new scenes from existing ones. A prototype implementation is described which allows queries to be specified either via an animation sketch or using the moving object algebra. 相似文献
78.
79.
This paper develops an adaptive fuzzy controller for robot manipulators using a Markov game formulation. The Markov game framework offers a promising platform for robust control of robot manipulators in the presence of bounded external disturbances and unknown parameter variations. We propose fuzzy Markov games as an adaptation of fuzzy Q-learning (FQL) to a continuous-action variation of Markov games, wherein the reinforcement signal is used to tune online the conclusion part of a fuzzy Markov game controller. The proposed Markov game-adaptive fuzzy controller uses a simple fuzzy inference system (FIS), is computationally efficient, generates a swift control, and requires no exact dynamics of the robot system. To illustrate the superiority of Markov game-adaptive fuzzy control, we compare the performance of the controller against a) the Markov game-based robust neural controller, b) the reinforcement learning (RL)-adaptive fuzzy controller, c) the FQL controller, d) the Hinfin theory-based robust neural game controller, and e) a standard RL-based robust neural controller, on two highly nonlinear robot arm control problems of i) a standard two-link rigid robot arm and ii) a 2-DOF SCARA robot manipulator. The proposed Markov game-adaptive fuzzy controller outperformed other controllers in terms of tracking errors and control torque requirements, over different desired trajectories. The results also demonstrate the viability of FISs for accelerating learning in Markov games and extending Markov game-based control to continuous state-action space problems. 相似文献
80.
Statistical pattern recognition traditionally relies on feature-based representation. For many applications, such vector representation is not available and we only possess proximity data (distance, dissimilarity, similarity, ranks, etc.). In this paper, we consider a particular point of view on discriminant analysis from dissimilarity data. Our approach is inspired by the Gaussian classifier and we defined decision rules to mimic the behavior of a linear or a quadratic classifier. The number of parameters is limited (two per class). Numerical experiments on artificial and real data show interesting behavior compared to Support Vector Machines and to kNN classifier: (a) lower or equivalent error rate, (b) equivalent CPU time, (c) more robustness with sparse dissimilarity data. 相似文献