全文获取类型
收费全文 | 1993篇 |
免费 | 83篇 |
国内免费 | 12篇 |
专业分类
2088篇 |
出版年
2024年 | 6篇 |
2023年 | 10篇 |
2022年 | 8篇 |
2021年 | 45篇 |
2020年 | 15篇 |
2019年 | 140篇 |
2018年 | 152篇 |
2017年 | 166篇 |
2016年 | 109篇 |
2015年 | 91篇 |
2014年 | 54篇 |
2013年 | 74篇 |
2012年 | 35篇 |
2011年 | 33篇 |
2010年 | 19篇 |
2009年 | 33篇 |
2008年 | 25篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 20篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 94篇 |
1984年 | 88篇 |
1983年 | 82篇 |
1982年 | 91篇 |
1981年 | 72篇 |
1980年 | 89篇 |
1979年 | 97篇 |
1978年 | 75篇 |
1977年 | 64篇 |
1976年 | 56篇 |
1975年 | 30篇 |
1974年 | 46篇 |
1973年 | 28篇 |
排序方式: 共有2088条查询结果,搜索用时 0 毫秒
181.
Understanding of second-order belief structures by 5- and 10-year-old children was assessed in acted stories in which two characters (John and Mary) were independently informed about an object's (ice-cream van's) unexpected transfer to a new location. Hence both John and Mary knew where the van was but there was a mistake in John's second-order belief about Mary's belief: “John thinks Mary thinks the van is still at the old place”. Children's understanding of this second-order belief was tested by asking “Where does John think Mary will go for ice cream?” Correct answers could only be given if John's second-order belief was represented, since all shortcut reasoning based on first-order beliefs would have led to the wrong answer. Results suggested unexpected early competence around the age of 6 and 7 years, shown under optimal conditions when inference of second-order beliefs was prompted. 相似文献
182.
Theodore M Alper 《Journal of mathematical psychology》1985,29(1):73-81
Real relational structures of scale type (1, 2) can be represented in the reals in such a way that the induced automorphism group is properly contained in the affine group and itself properly contains the group of translations. There are no real relational structures of scale type (m, m + 1), m ≥ 2. 相似文献
183.
In a conditioned inhibition paradigm (A+, B+, AX?_, pigeons received either of two keylight stimuli reliably followed by food (A+, B+). However, when one of these keylights was accompanied by another stimulus, food did not follow (AX?). For some groups, the putative inhibitor was a tone, whereas for others it was illumination of a red houselight. The birds pecked the A and B stimuli at a high rate. When X was red houselight, the birds pecked A at a much lower rate in the presence of X. When X was a tone, discrimination between A and AX was much poorer. Moreover, in a transfer test, red houselight inhibited responding to the other keylight, B, but tone did not. These results indicate that red houselight becomes a conditioned inhibitor more quickly than tone in appetitive situations, just as red houselight becomes a conditioned excitor more quickly in those situations. These results contradict the assertion that the latter outcome occurs because red houselight is a stronger appetitive excitor than tone at the start of the experiment (the “head start” hypothesis). 相似文献
184.
M Moscovitch 《Brain and language》1976,3(1):47-71
Laterality experiments using reaction time were conducted to assess the performance of the right hemisphere of normal people on verbal tasks. The results show that if the task calls for pictorial encoding of visually presented verbal material, then the right hemisphere's performance is superior to that of the left. When the task calls for linguistic analysis, the minor hemisphere displays no aptitude in dealing with the task. The latter finding is at variance with data from split-brain research. To reconcile these differences, it was proposed that language functions, though represented in the right hemisphere of normal people, are functionally localized in the left. When the control which the left hemisphere exerts over the right is weakened or removed, e.g., by commissurotomy, right hemisphere language is released. The application of this model to other neurological phenomena is briefly discussed. 相似文献
185.
Douglas S. Grant 《Learning and motivation》1976,7(4):580-590
The effect of sample stimulus presentation time on long-delay matching in highly practiced pigeons was investigated. The birds were found capable of above chance matching performance at a delay of 60 sec provided the sample stimulus was presented for 4 sec or longer. Matching accuracy increased as a negatively accelerated function of sample stimulus presentation time and decreased as a negatively accelerated function of time since the termination of the sample. The rate of forgetting was found to be independent of sample stimulus presentation time. The data were inconsistent with a temporal discrimination interpretation of the effect of presentation time on delayed matching. The data were interpreted as supporting a simple trace strength and decay model of pigeon delayed matching. 相似文献
186.
187.
血红素氧合酶-1(HO-1)是血红素分解的起始酶和限速酶,它分解血红素最终生成胆红素、一氧化碳和铁.这三种产物通过抗炎症损伤、抗氧化应激、抗细胞增殖、抗细胞凋亡、抑制血小板聚集、调节血管张力及细胞内信号传递等途径对心血管系统起着重要的保护作用.研究显示,HO的诱导剂及多种能降低心血管病风险的药物能诱导 HO-1表达增加,从而起到抗动脉粥样硬化的发生发展及调节血压的作用.因此开发临床可应用的HO诱导剂,甚至开发HO的基因治疗方法是目前研究的方向. 相似文献
188.
Most clinical research assumes that modulation of facial expressions is lateralized predominantly across the right-left hemiface. However, social psychological research suggests that facial expressions are organized predominantly across the upper-lower face. Because humans learn to cognitively control facial expression for social purposes, the lower face may display a false emotion, typically a smile, to enable approach behavior. In contrast, the upper face may leak a person’s true feeling state by producing a brief facial blend of emotion, i.e. a different emotion on the upper versus lower face. Previous studies from our laboratory have shown that upper facial emotions are processed preferentially by the right hemisphere under conditions of directed attention if facial blends of emotion are presented tachistoscopically to the mid left and right visual fields. This paper explores how facial blends are processed within the four visual quadrants. The results, combined with our previous research, demonstrate that lower more so than upper facial emotions are perceived best when presented to the viewer’s left and right visual fields just above the horizontal axis. Upper facial emotions are perceived best when presented to the viewer’s left visual field just above the horizontal axis under conditions of directed attention. Thus, by gazing at a person’s left ear, which also avoids the social stigma of eye-to-eye contact, one’s ability to decode facial expressions should be enhanced. 相似文献
189.
为了探讨肝激酶B1(LKB1)蛋白在食管鳞癌组织中的表达水平及其与食管鳞癌临床特征及生存期的关系,应用免疫组化方法检测120例食管鳞癌患者组织中LKB1蛋白表达情况并对诸多临床特征进行相关性分析研究,发现LKB1蛋白在食管癌旁正常组织的阳性表达率高于癌组织;LKB1蛋白表达与患者年龄、性别、肿瘤部位、病变长度及浸润深度无关而与分化程度、淋巴结转移及临床分期(TNM)相关,且LKB1蛋白阴性组预后较阳性组差.可见LKB1视为抑癌基因影响食管鳞癌的预后,可能成为食管鳞癌新型的临床预后指标之一. 相似文献
190.
本文对广州市2009年7月~2011年1月的发热呼吸道监测数据进行了定量分析,并在此分析的基础上提出了相关政策建议,比如加强人群分类管理、加快疫苗研制、避免抗病毒药物的滥用、重视健康管理和健康教育以及遵循预防控制原则等。 相似文献