全文获取类型
收费全文 | 5801篇 |
免费 | 1645篇 |
国内免费 | 725篇 |
出版年
2024年 | 10篇 |
2023年 | 33篇 |
2022年 | 55篇 |
2021年 | 168篇 |
2020年 | 181篇 |
2019年 | 453篇 |
2018年 | 366篇 |
2017年 | 490篇 |
2016年 | 442篇 |
2015年 | 414篇 |
2014年 | 367篇 |
2013年 | 721篇 |
2012年 | 430篇 |
2011年 | 411篇 |
2010年 | 426篇 |
2009年 | 400篇 |
2008年 | 392篇 |
2007年 | 409篇 |
2006年 | 379篇 |
2005年 | 358篇 |
2004年 | 244篇 |
2003年 | 212篇 |
2002年 | 168篇 |
2001年 | 135篇 |
2000年 | 109篇 |
1999年 | 97篇 |
1998年 | 40篇 |
1997年 | 37篇 |
1996年 | 29篇 |
1995年 | 30篇 |
1994年 | 21篇 |
1993年 | 23篇 |
1992年 | 14篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 13篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1973年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有8171条查询结果,搜索用时 15 毫秒
131.
We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a 'sinring', that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25-30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally. 相似文献
132.
133.
极权主义和政治现代性--读《极权主义的起源》 总被引:1,自引:0,他引:1
阿伦特的《极权主义的起源》是要揭示一种特殊的现代政治现象的起因和条件,探讨极权主义这个现代特有的现象的深层历史原因及其结构因素。正因为如此,她的许多观点和分析至今仍有重要的意义。极权主义是反犹主义、民族国家的衰落、种族主义、为扩张而扩张、资本和暴徒联盟结合在一起的产物。极权主义就是从根本上消灭人性,它反映了“我们世纪的危机”,揭示了西方文明及其价值体系的崩溃。 相似文献
134.
奥古斯丁《忏悔录》中的“时间之间”受到后世哲学家们的广泛关注和高度评价,但往往只重视其中“心灵的伸展”这一向度.而忽视上帝的创造这一向度,忽视了永恒之维。事实上,上帝的创造和心灵的伸展这两个向度不可分割.前者规定后者,阐明时间的起源;后者反映前者,说明时间的存在和本质。后者受前者的制约。也就是说,心灵的伸展有一个界限,是不可超越的。当文德尔班强调奥古斯丁的形而上学是“内在经验的形而上学”时,他确认了奥古斯丁时间观的心灵向度;当吉尔松称之为“皈依的形而上学”时,则是强调“心灵伸展的界限”,即永恒上帝的创造。 相似文献
135.
This article reports three experiments in which the representational nature of human object location memory was studied. The results show that multiple frames of reference can be used to encode the spatial relationships among objects. Depending on their dominancy, availability, and validity, these multiple representations interact to determine memory performance. Specifically, representations that are automatically encoded and extensively practiced are more dominant, and their availability improves performance when they are valid. On the other hand, when the dominant representations are available but invalid, people may have to resort to the less dominant representations. As a result, the availability of these dominant but invalid representations can actually hurt performance, due to interference. If these interfering representations are eliminated, the performance is again improved. The implications of these findings for general human spatial cognition are discussed. 相似文献
136.
In this paper, we discuss the weakness of current action languages for sensing actions with respect to modeling domains with
multi-valued fluents. To address this problem, we propose a language with sensing actions and multi-valued fluents, called
AMK, provide a transition function based semantics for the language, and demonstrate its use through several examples from the
literature. We then define the entailment relationship between action theories and queries in AMK, denoted by ⊧AMK, and discuss some properties about AMK. 相似文献
137.
Swaisgood RR White AM Zhou X Zhang G Lindburg DG 《Journal of comparative psychology (Washington, D.C. : 1983)》2005,119(3):325-334
This study investigated the responses of 14 giant pandas (Ailuropoda melanoleuca) to 5 enrichment items (3 manipulable objects, 2 feeding devices) that possess different properties affording varying behavioral opportunities. Enrichment items were quantitatively described by using 12 properties. Pandas displayed no preferences among the 5 enrichment treatments, all of which had similar positive effects on behavioral measures of well-being (behavioral diversity, stereotypy). However, each item promoted a distinct behavioral profile, readily mapped onto the enrichment's properties. These results suggest that it may be important to stimulate behavioral diversity but that specific behaviors or enrichment properties are not required. The unique behavioral topography seen with these enrichments also suggests that providing multiple enrichments with varying properties will maximize overall behavioral diversity. 相似文献
138.
中国西南少数民族与道教神仙信仰 总被引:2,自引:0,他引:2
随秦汉以来中华民族多元一体格局的形成,道教逐渐传播进入西南少数民族地区.本文通过西南少数民族地区神仙信仰典型事例的论析,说明道教与西南少数民族文化的相互融摄,构成了具有地域特色的中国传统文化. 相似文献
139.
Wigal SB McGough JJ McCracken JT Biederman J Spencer TJ Posner KL Wigal TL Kollins SH Clark TM Mays DA Zhang Y Tulloch SJ 《Journal of attention disorders》2005,9(1):275-289
Mixed amphetamine salts extended release (MAS XR; Adderall XR) and atomoxetine (Strattera) were compared in children 6 to 12 years old with attention deficit/hyperactivity disorder (ADHD) combined or hyperactive/impulsive type in a randomized, double-blind, multicenter, parallel-group, forced-dose-escalation laboratory school study. Primary efficacy measure was the SKAMP (Swanson, Kotkin, Agler, M-Flynn, and Pelham) behavioral rating scale. Changes in mean SKAMP deportment scores from baseline were significantly greater for MAS XR (n = 102) than for atomoxetine (n = 101) overall (-0.56 and -0.13, respectively; p < .0001) and at each week (p < .001). Adverse events were similar for both treatment groups. The extended time course of action and greater therapeutic efficacy of MAS XR suggests that it is more effective than atomoxetine in children with ADHD. 相似文献
140.
Darlene L. Witte‐Townsend Emily DiGiulio 《International Journal of Children's Spirituality》2004,9(2):127-142
Witte‐Townsend and DiGiulio explore some of the dimensions of knowing that children, teachers and parents may engage together during story‐time. They reflect on some of their own long‐term relationships with children and children's books, especially Phoebe Gilman's Something from nothing (published in 1992) and Simms Taback's Joseph had a little overcoat, published in 1999. The authors probe issues such as why children ask to hear a favourite story over and over and why they suddenly abandon all interest and move on to a new book. They explore the meaning of the silences that sometimes arise during story‐time, pooling around the young listeners as the last words of the book are read. Witte‐Townsend and DiGiulio remind us of the value of literature in the lives of children and they affirm that the reading and re‐reading of favourite stories enables the understanding of complex human issues and contributes significantly to social, emotional and spiritual growth. 相似文献