全文获取类型
收费全文 | 430篇 |
免费 | 24篇 |
国内免费 | 23篇 |
专业分类
电工技术 | 7篇 |
综合类 | 55篇 |
化学工业 | 12篇 |
金属工艺 | 7篇 |
机械仪表 | 5篇 |
建筑科学 | 94篇 |
矿业工程 | 7篇 |
能源动力 | 2篇 |
轻工业 | 7篇 |
水利工程 | 3篇 |
石油天然气 | 8篇 |
无线电 | 7篇 |
一般工业技术 | 20篇 |
冶金工业 | 26篇 |
原子能技术 | 2篇 |
自动化技术 | 215篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 10篇 |
2014年 | 16篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 10篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 17篇 |
2007年 | 29篇 |
2006年 | 18篇 |
2005年 | 54篇 |
2004年 | 43篇 |
2003年 | 13篇 |
2002年 | 17篇 |
2001年 | 30篇 |
2000年 | 16篇 |
1999年 | 14篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有477条查询结果,搜索用时 15 毫秒
1.
地应力对岩心渗透率伤害实验及机理分析 总被引:15,自引:4,他引:11
生产实际情况表明,有许多油气田对应力较为敏感。随着生产的进行,储集层压力下降,有效应力不断变化,引起油藏产能逐渐降低。为研究这一规律和变化规律,阐述了应用岩民测试有效应力对渗透率影响的实验原理,在对实验数据进行统计分析的基础上,拟合出有效应力与渗透经的函数关系(二次多项式)。应用毛细管渗流概念以有弹性厚壁筒厚理,研究了随着毛细管管壁内外压差变化时,毛细管内半径变化有其对毛细管渗流能力的影响,所得结论与实验结果一致。在实际生产中,应控制油藏压力快速大幅度下降,避免有效应力变化引起油藏渗流能力下降和减产。 相似文献
2.
No authorship indicated 《Canadian Metallurgical Quarterly》2003,58(11):931
Provides the biography of David W. Johnson and announces that he has won the Award for Distinguished Contributions of Applications of Psychology to Education and Training for programmatic research, comprehensive research reviews, and revision of theory over four decades of persistence that have provided the knowledge foundation for cooperative learning, constructive controversy, conflict resolution, and peer mediation training. A selected bibliography is also provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
This paper introduces and evaluates a new class of knowledge model, the recursive Bayesian multinet (RBMN), which encodes the joint probability distribution of a given database. RBMNs extend Bayesian networks (BNs) as well as partitional clustering systems. Briefly, a RBMN is a decision tree with component BNs at the leaves. A RBMN is learnt using a greedy, heuristic approach akin to that used by many supervised decision tree learners, but where BNs are learnt at leaves using constructive induction. A key idea is to treat expected data as real data. This allows us to complete the database and to take advantage of a closed form for the marginal likelihood of the expected complete data that factorizes into separate marginal likelihoods for each family (a node and its parents). Our approach is evaluated on synthetic and real-world databases. 相似文献
4.
测井岩性识别是石油勘探中十分重要的基础工作,准确的岩性识别结果可以为勘探和开发提供可靠的依据。人工神经网络方法可对复杂的高维数据进行非线性映射,在模式识别领域得到越来越广泛的应用。针对传统的BP神经网络算法存在收敛速度慢、隐层数以及隐层节点数难以确定等缺点,研究了一种构造性神经网络学习算法---级联算法(Cascade Correlation Algorithm,简称CC算法)及其在石油工程中的应用。采用该算法对甘肃镇原-泾川地区进行岩性识别研究,通过与BP神经网络的识别结果进行比较,体现出构造性神经网络的优越性。 相似文献
5.
Mi Thxi 《计算机科学技术学报》1997,12(5):425-440
The original interpretation of the constructive set theory CZF in Martin-Loef‘s type theory uses the‘extensional identity types’.It is generally believed that these‘types’do not belong to type theory.In this paper it will be shown that the interpretation goes through without identity types.This paper will also show that the interpretation can be given in an intensional type theory.This reflects the computational nature of the interpretation.This computational aspect is reinforced by an ω-Set moel of CZF. 相似文献
6.
Lucja Iwanska 《Computational Intelligence》1997,13(3):348-390
Intensional negative adjectives alleged , artificial , fake , false , former , and toy are unusual adjectives that depending on context may or may not be restricting functions. A formal theory of their semantics, pragmatics, and context that uniformly accounts for their complex mathematical and computational characteristics and captures some peculiarities of individual adjectives is presented.
Such adjectives are formalized as new concept builders, negation‐like functions that operate on the values of intensional properties of the concepts denoted by their arguments and yield new concepts whose intensional properties have values consistent with the negation of the old values. Understanding these new concepts involves semantics, pragmatics and context‐dependency of natural language. It is argued that intensional negative adjectives can be viewed as a special‐purpose, weaker, conntext‐dependent negationin natural language. The theory explains and predicts many inferences licensed by expressions involving such adjectives. Implementation of sample examples demonstrates its computational feasibility. Computation of context‐dependent interpretation is discussed.
The theory allows one to enhance a knowledge representation system with similar concept building, negation‐like, context‐dependent functions, the availability of which appears to be a distinct characteristic of natural languages. 相似文献
Such adjectives are formalized as new concept builders, negation‐like functions that operate on the values of intensional properties of the concepts denoted by their arguments and yield new concepts whose intensional properties have values consistent with the negation of the old values. Understanding these new concepts involves semantics, pragmatics and context‐dependency of natural language. It is argued that intensional negative adjectives can be viewed as a special‐purpose, weaker, conntext‐dependent negationin natural language. The theory explains and predicts many inferences licensed by expressions involving such adjectives. Implementation of sample examples demonstrates its computational feasibility. Computation of context‐dependent interpretation is discussed.
The theory allows one to enhance a knowledge representation system with similar concept building, negation‐like, context‐dependent functions, the availability of which appears to be a distinct characteristic of natural languages. 相似文献
7.
Since Samuel's work on checkers over thirty years ago, much effort has been devoted to learning evaluation functions. However, all such methods are sensitive to the feature set chosen to represent the examples. If the features do not capture aspects of the examples significant for problem solving, the learned evaluation function may be inaccurate or inconsistent. Typically, good feature sets are carefully handcrafted and a great deal of time and effort goes into refining and tuning them. This paper presents an automatic knowledge-based method for generating features for evaluation functions. The feature set is developed iteratively: features are generated, then evaluated, and this information is used to develop new features in turn. Both the contribution of a feature and its computational expense are considered in determining whether and how to develop it further.
This method has been applied to two problem-solving domains: the Othello board game and the domain of telecommunications network management. Empirical results show that the method is able to generate many known features and several novel features and to improve concept accuracy in both domains. 相似文献
This method has been applied to two problem-solving domains: the Othello board game and the domain of telecommunications network management. Empirical results show that the method is able to generate many known features and several novel features and to improve concept accuracy in both domains. 相似文献
8.
9.
王坦 《数码设计:surface》2014,(5):171-173
随着社会的发展,人居环境日新月异,景观设计专业顺理成章的成为各大院校的热门专业。但课程设置体系中存在着诸多问题。未能做到因材施教。本文针对艺术院校景观专业的现存问题,提出课程教学应着手于小尺度空间。以工作模型作为主要研究载体,渐进的培养掌生综合分析问题的能力,提高学生的空间感知,运用构成艺术语言转译空间精神,营造个性的艺术空间。 相似文献
10.
张胜礼 《计算机科学与探索》2014,(4):494-505
对于模糊知识及其否定关系,潘正华指出应该明确地分为矛盾否定关系、对立否定关系和中介否定关系,并建立了一种具有矛盾否定、对立否定和中介否定的模糊集FScom(fuzzy sets with contradictory negation, opposite negation and medium negation),随后建立了一种改进的模糊集IFScom(improved FScom)。为给模糊集FScom及其改进IFScom提供一种逻辑工具,提出了一种带有矛盾否定、对立否定和中介否定的模糊命题逻辑演算系统FPcom,并在给定无穷值语义赋值模型以及可满足性定义下,证明了FPcom具有可靠性和完备性。FPcom在一定意义上可视为对中介命题演算系统的改进。 相似文献