全文获取类型
收费全文 | 3254篇 |
免费 | 395篇 |
国内免费 | 831篇 |
出版年
2024年 | 5篇 |
2023年 | 73篇 |
2022年 | 86篇 |
2021年 | 122篇 |
2020年 | 154篇 |
2019年 | 134篇 |
2018年 | 143篇 |
2017年 | 155篇 |
2016年 | 165篇 |
2015年 | 123篇 |
2014年 | 139篇 |
2013年 | 321篇 |
2012年 | 207篇 |
2011年 | 256篇 |
2010年 | 240篇 |
2009年 | 230篇 |
2008年 | 247篇 |
2007年 | 309篇 |
2006年 | 280篇 |
2005年 | 254篇 |
2004年 | 179篇 |
2003年 | 119篇 |
2002年 | 73篇 |
2001年 | 50篇 |
2000年 | 51篇 |
1999年 | 43篇 |
1998年 | 37篇 |
1997年 | 29篇 |
1996年 | 21篇 |
1995年 | 30篇 |
1994年 | 29篇 |
1993年 | 20篇 |
1992年 | 15篇 |
1991年 | 17篇 |
1990年 | 11篇 |
1989年 | 17篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1977年 | 3篇 |
1972年 | 2篇 |
1962年 | 3篇 |
1961年 | 2篇 |
排序方式: 共有4480条查询结果,搜索用时 15 毫秒
231.
232.
2~3.5岁是婴儿成长到幼儿的重要发展转折期,也是儿童执行功能及言语能力的发展萌芽期。研究通过测查北京市81名2~3.5岁儿童在固定盒子任务、搭积木任务、A非B任务和皮博迪图片词汇测验上的表现,探究了该年龄段儿童执行功能的发展特点、各成分间的内部关系、以及言语能力对执行功能的影响。结果发现:(1)在2~3.5岁期间,除认知灵活性外,儿童的工作记忆与抑制控制均快速发展,其中,2.5岁前后是工作记忆与抑制控制的重要发展时期;(2)在2~3岁期间,认知灵活性与工作记忆之间相关密切,在3~3.5岁期间,认知灵活性与抑制控制的相关密切,3岁是儿童执行功能内部成分关系的重要发展转折期;(3)在2~3.5岁期间,儿童言语能力呈现快速发展,并且言语能力对该年龄段执行功能各成分间关系产生一定的影响,但不同言语能力的儿童在执行功能各成分的表现并没有显著差异。 相似文献
233.
234.
在19世纪70~90年代的中国,当指称"mental philosophy"与"psychology"时,译者主要使用了"性学"、"心理(学)"、"性理(学)"、"心才学"、"心灵学"和"心学"等6个名称。据现有史料,尽管汉语"心理学"一词由执权居士于1872年首译,但当时并未受到中国学人的重视。现在通行的汉语"心理学"一词是来自日本人西周,经康有为与梁启超等人的共同努力才逐渐被中国人所接受,并于1902年以后被普遍使用。汉语"心理学"一词在这场"比赛"中能够最终胜出,内因是既受中国文化传统和思维方式的影响,又为避免将一门新兴学科等同于旧学科从而产生"新瓶装旧酒"的误会;外因是中国新学科体系在创建时深受日本和西方国家的影响。 相似文献
235.
For bulk piezoelectric ceramics plates, the fundamental thickness-stretch (TSt) waves are always coupled to the in-plane extension waves and the symmetric thickness-shear waves. The occurrence of these spurious modes in bulk piezoelectric ceramics plates is undesirable as it may interfere with the operation of transducers. 1–3 piezoelectric composites are promising candidates to suppress the spurious modes mentioned above. However, theoretical modelling of multiphase ceramic composite objects is very complex. In this study, a simple analytical TSt vibration model is constructed from three-dimensional equations of linear piezoelectricity. The mechanical damping is considered in the model by introducing a complex elastic constant. The performance of 1–3 piezoelectric composites is analysed and the electrical impedance results from theoretical and experimental analysis are compared. The results show that there is excellent agreement between the experimental electrical impedance and that obtained by the theoretical TSt vibration analysis. This indicates that 1–3 piezoelectric composites can be operated in a nearly pure TSt vibration mode near the fundamental resonance. The analytical model we present is valid for analysing 1–3 piezoelectric composites plates with large aspect ratios quickly and efficiently. 相似文献
236.
Dafan Du Jiang Wang Yves Fautrelle Zhongming Ren Rene Moreau 《Philosophical Magazine Letters》2015,95(8):425-432
The application of a high magnetic field is capable of inducing the formation of aligned equiaxed grains in alloys during directional solidification. The alignment and refinement of the grains is enhanced as the magnetic field intensity increases. The thermoelectric power difference at the liquid/solid interface in four alloys has been measured in situ during directional solidification and it is concluded that the formation of aligned equiaxed grains in a magnetic field should be attributed to the combined action of a thermoelectric magnetic force and a magnetization force. 相似文献
237.
The directional solidification process of ternary Ag42.4Cu21.6Sb36 eutectic alloy within a wide growth rate range from 2 to 60 μm/s was accomplished at a constant temperature gradient of 50 K/cm. As growth rate increases, the ternary (θ(Cu2Sb) + ε(Ag3Sb) + Sb) eutectic morphology evolves from “lamellar (θ + ε) plus fibrous (Sb)” structure into “(θ + Sb) fibres in continuous ε matrix” structure. The θ and (Sb) phase spacings decrease with the increase of growth rate according to power functions with exponent values of 0.55 and 0.56, respectively. It is also found that the microhardness of directionally solidified Ag42.4Cu21.6Sb36 alloy samples is enhanced with the increase of growth rate, and the decrease of θ and (Sb) phase spacings. 相似文献
238.
239.
This special issue of Memory brings together research from around the globe, from Japanese, Chinese and East Indian cultures, to American and European societies, to the Caribbean, to Turkey and to Australia and New Zealand, which examines how and why people, from childhood to old age, remember the personal past in daily life. This journey highlights the important role of the cultural context in shaping the functional usages of autobiographical memory. We illuminate six major contributions of cross-cultural research to a broader and deeper understanding of the functions of autobiographical memory, and call attention to the filed that memory research must “go global.” 相似文献
240.
This study investigated explicit knowledge of autobiographical memory functions using a newly developed questionnaire. European and Asian American adults (N = 57) and school-aged children (N = 68) indicated their agreement with 13 statements about why people think about and share memories pertaining to four broad functions—self, social, directive and emotion regulation. Children were interviewed for personal memories concurrently with the memory function knowledge assessment and again 3 months later. It was found that adults agreed to the self, social and directive purposes of memory to a greater extent than did children, whereas European American children agreed to the emotion regulation purposes of memory to a greater extent than did European American adults. Furthermore, European American children endorsed more self and emotion regulation functions than did Asian American children, whereas Asian American adults endorsed more directive functions than did European American adults. Children's endorsement of memory functions, particularly social functions, was associated with more detailed and personally meaningful memories. These findings are informative for the understanding of developmental and cultural influences on memory function knowledge and of the relation of such knowledge to autobiographical memory development. 相似文献