全文获取类型
收费全文 | 729篇 |
免费 | 41篇 |
国内免费 | 86篇 |
专业分类
化学 | 11篇 |
力学 | 1篇 |
综合类 | 20篇 |
数学 | 780篇 |
物理学 | 44篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 24篇 |
2021年 | 18篇 |
2020年 | 19篇 |
2019年 | 33篇 |
2018年 | 24篇 |
2017年 | 21篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 27篇 |
2013年 | 112篇 |
2012年 | 22篇 |
2011年 | 26篇 |
2010年 | 31篇 |
2009年 | 38篇 |
2008年 | 37篇 |
2007年 | 34篇 |
2006年 | 37篇 |
2005年 | 40篇 |
2004年 | 19篇 |
2003年 | 34篇 |
2002年 | 27篇 |
2001年 | 34篇 |
2000年 | 37篇 |
1999年 | 21篇 |
1998年 | 34篇 |
1997年 | 23篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1959年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有856条查询结果,搜索用时 31 毫秒
171.
172.
Let (C,E,s) be an extriangulated category with a proper class ξ of E-triangles.We study complete cohomology of objects in (C,E,s) by applying ξ-projective resolutions and ξ-injective coresolutions constructed in (C,E,s).Vanishing of complete cohomology detects objects with finite ξ-projective dimension and finite ξ-injective dimension.As a consequence,we obtain some criteria for the validity of the Wakamatsu tilting conjecture and give a necessary and sufficient condition for a virtually Gorenstein algebra to be Gorenstein.Moreover,we give a general technique for computing complete cohomology of objects with finite ξ-Gprojective dimension.As an application,the relations between ξ-projective dimension and ξ-Gprojective dimension for objects in (C,E,s) are given. 相似文献
173.
With the continuous improvement of people’s health awareness and the continuous progress of scientific research, consumers have higher requirements for the quality of drinking. Compared with high-sugar-concentrated juice, consumers are more willing to accept healthy and original Not From Concentrated (NFC) juice and packaged drinking water. At the same time, drinking category detection can be used for vending machine self-checkout. However, the current drinking category systems rely on special equipment, which require professional operation, and also rely on signals that are not widely used, such as radar. This paper introduces a novel drinking category detection method based on wireless signals and artificial neural network (ANN). Unlike past work, our design relies on WiFi signals that are widely used in life. The intuition is that when the wireless signals propagate through the detected target, the signals arrive at the receiver through multiple paths and different drinking categories will result in distinct multipath propagation, which can be leveraged to detect the drinking category. We capture the WiFi signals of detected drinking using wireless devices; then, we calculate channel state information (CSI), perform noise removal and feature extraction, and apply ANN for drinking category detection. Results demonstrate that our design has high accuracy in detecting drinking category. 相似文献
174.
媒介文化即具有伦理属性的生活方式,被赋予“权力”属性的媒介文化仅系单向度的权能范畴,仅适合于特定的媒介制度。自律失效所致的媒介文化“公地悲剧”可描述为违背法律的、悖离道德的或充满伦理争议的缺陷,技术因素不能证成“公地悲剧”不可避免性。伦理而非权利范畴的媒介文化,其价值倚重在于“内在美”的尺度性、实体而非形式的“公正”品质,内在美排斥了单纯生物性的悦目与感观享受,凸显“理想美”“悲剧美”。蕴涵丰富的实体公正关注超越对善、恶判断的表层认识,更多地寻求在显著符号意义之外所暗含的“外溢效应”。 相似文献
175.
176.
177.
Minoru Hirano 《Journal of voice》1988,2(4):291-300
Behavior of the cricothyroid, lateral cricoarytenoid, vocalis, and interarytenoid muscles of William D. Vennard was electromyographically investigated. This article demonstrates electromyographic recordings that have not been published. Data presentation and discussion are focused on vocal registers, some phrases for voice training and warm-up, vowels, phonation modes, fundamental frequency control, the interarytenoid muscle, and some nonsinging behaviors 相似文献
178.
代数表示论的某些新进展 总被引:1,自引:0,他引:1
代数表示理论是代数学的一个新的重要分支,在近二十五年的时间里,这一理论有很大的发展,关于代数表示的基础理论的介绍可参见文献(101),本文主要从Hall代数和拟遗传代数两个方面介绍代数表示论的一些最新进展,第一章给出了Hall代数的基本理论及其方法,并且着重指出了利用这一理论和方法通过代数表示论去实现Kac-Moody李代数及相应的量子包络代数,第二章介绍了拟遗传代数及其表示理论,以及这一理论与复 相似文献
179.
Henning Krause 《Algebras and Representation Theory》2003,6(5):475-499
Given a locally presentable additive category A, we study a class of covariantly finite subcategories which we call definable. A definable subcategory arises from a set of coherent functors F
i
on A by taking all objects X in A such that F
i
X=0 for all i. We give various characterizations of definable subcategories, demonstrating that all covariantly finite subcategories which arise in practice are of this form. This is based on a filtration of the category of all coherent functors on A. 相似文献
180.
Oleh R. Nykyforchyn 《Applied Categorical Structures》2007,15(3):243-257
For a compact Hausdorff topological lattice L the set M
L
X of L-valued normed regular capacities on a compact Hausdorff topological space X is investigated. It is shown that the set M
L
X carries a compact Hausdorff topology, and M
L
extends to a weakly τ-normal functor in the category of compacta. If L is an upper and lower Lawson semilattice, then M
L
is the functorial part of two semimonads. These semimonads coincide and are a monad if and only if L is distributive, i.e., is a Lawson lattice. The obtained results have a natural interpretation if capacities are regarded
as subjective estimates of likelihood of realization of events in conditions of uncertainty.
相似文献