全文获取类型
收费全文 | 874篇 |
免费 | 82篇 |
国内免费 | 105篇 |
专业分类
1061篇 |
出版年
2024年 | 3篇 |
2023年 | 24篇 |
2022年 | 24篇 |
2021年 | 33篇 |
2020年 | 39篇 |
2019年 | 23篇 |
2018年 | 32篇 |
2017年 | 36篇 |
2016年 | 34篇 |
2015年 | 26篇 |
2014年 | 41篇 |
2013年 | 128篇 |
2012年 | 61篇 |
2011年 | 44篇 |
2010年 | 54篇 |
2009年 | 48篇 |
2008年 | 51篇 |
2007年 | 56篇 |
2006年 | 57篇 |
2005年 | 35篇 |
2004年 | 19篇 |
2003年 | 16篇 |
2002年 | 8篇 |
2001年 | 19篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1968年 | 3篇 |
1957年 | 3篇 |
1951年 | 4篇 |
1950年 | 3篇 |
排序方式: 共有1061条查询结果,搜索用时 7 毫秒
891.
The effects of a specific presynaptic cholinergic antagonist, toosendanin, on memory formation following a passive avoidance training experience in day-old chicks was investigated. Bilateral injection of toosendanin into the neostriatal/hyperstriatal region of the chick forebrain produced memory impairment in a dose-dependent manner. Retention deficits were apparent from 20 min following training in chicks treated with toosendanin, regardless of the injection time relative to training. Chicks that received injections of the drug at corresponding times prior to retention tests showed normal retention levels, suggesting that toosendanin has no effect on performance and memory retrieval. These results indicate an involvement of cholinergic transmission during an early stage of memory formation. 相似文献
892.
The purpose of this study was to evaluate the effectiveness of oral reading as a teaching technique for improving reading comprehension of 11 Educable Mentally Handicapped or Severe Learning Disabled adolescents. Students were tested on their ability to answer comprehension questions from a short factual article. Comprehension improved following the oral reading for students with a reading grade equivalent of less than 5.5 (measured from the Wide Range Achievement Test) but not for those students having a grade equivalent of greater than 5.5. This association was statistically significant (p = less than .01). Oral reading appeared to improve comprehension among the poorer readers but not for readers with moderately high ability. 相似文献
893.
The cooperative and competitive behavior of 8–9 year old children in urban and rural Korea was assessed by three different experimental techniques. The urban children were significantly more competitive and less cooperative in experiments 1 and 2, experiments in which the competitive alternative involved direct overt conflict. Both groups were highly competitive in experiment 3 in which the competitive alternative was less overt. 相似文献
894.
895.
896.
T Schallert I Q Whishaw K P Flannigan 《Journal of comparative psychology (Washington, D.C. : 1983)》1977,91(3):598-610
Three doses each of cathodal or anodal direct current were delivered to coagulate lateral hypothalamic tissue bilaterally in rats. Increases in hypothalamic tissue damage were associated with more instances of aphagia, greater amounts of glandular, but not rumenal, gastric pathology, and greater weight loss. Both anodal and cathodal lesions produced aphagia and similar amounts of gastric pathology, but anodal lesions also appeared to facilitate weight loss independently of the tissue damage. Extensive chromatolysis surrounding anodal lesion cavities may be importantly related to the postoperative effects. In additional experiments, anodal electrolytic lesions or cortical suction ablations were used to vary the location of neural damage. Fedding deficits and gastric pathology resulted from the destruction of several brain areas. In particular, eating of dry food in the presence of high gastric pathology was observed in rats with lesions ventral and medial to an area in the dorsolateral hypothalamus that was associated with aphagia. When aphagia was accompained by severe gastric pathology, the brain lesions typically encroached extensively on more ventromedial areas. Moreover, aphagia sometimes was observed with only negligible gastric pathology. It is suggested that gastric pathology is not primary to the expression of the aphagia that follows lateral hypothalamic damage. 相似文献
897.
Stroop performance was compared in primary Vietnamese- vs English-speaking individuals (age range 19-68 years), currently living in the USA. A modified Vietnamese Stroop task mimicked word, color, and interference effects of an English-language Stroop test. Stroop performance (items correctly completed and interference "cost") did not differ significantly between 30 Vietnamese Americans whose first language was Vietnamese (M age 34.3 yr.) vs 30 American-born individuals whose first language was English (M age 31.2 yr.). Expected performance decrements with aging were observed in English-language Stroop performance but not in Vietnamese-language Stroop performance, which instead exhibited a trend towards the opposite pattern. Unexpected group differences associated with age in Stroop performance may reflect subtle differences in task demands, not evident in simple category performance scores, or alternatively, cultural or neuropsychological differences in the study groups. 相似文献
898.
Jing Q 《Psychology and developing societies》1994,6(1):29-53
China's population explosions of the early 1950s and late 1960s, followed by the launching of the one-child population policy, can be expected to have an effect on the country's demographic structure that will persist for another 60-80 years. The proportion of the population over 60 years of age should increase from 7.6% in 1982 to a peak of 25.3% by 2040. As a result, by the mid-21st century, a labor force comprised of half the population will be supporting equal numbers of young and aged people. Although political and economic utility factors make it unlikely that China's fertility rate will ever fall below 2.0, the steady aging of society will have long-term social as well as demographic consequences. Increased material and emotional investment in children, brought about by the one-child policy, may compete with investments in the needs of the aged. Recommended is consolidation of a three-generation family system in which grandparents help to maintain family interdependence and provide child care in exchange for support from their adult children. Such a model is consistent with the Confucian emphasis on respect for the wisdom of the elderly and responsibility for their well-being. 相似文献
899.
According to our clinical observations from various aspects of stroke patients, such as the total incidence of aphasia, the incidence of aphasia after left brain damage of the dextrals, the aphasia that occurs in patients without hemiplegia, and the types of aphasia, a much higher incidence of crossed aphasia is seen among the stroke patients of the Han (the largest ethnic group in China) as compared with the Uighur-Kazaks (U-K) in China and the Occidentals documented in the literature. Motor aphasia is most common and pure sensory or posterior aphasia is rarely seen in Han patients. The distinct features of the Chinese language is a possible explanation for this difference. We suspect that language function of the Han is not localized in the left brain but in the right or both hemispheres. There is no definite Wernicke's area in the left brain of the Chinese people and the neural pathway of the language function in the brain of the Chinese people is not similar to people who speak phonetic languages. Consequently the universal applicability of the theories of cerebral laterality of the language function and dominant hemisphere established by Dax and Broca are questioned in this paper. 相似文献
900.
G. Schiefer M. Harkin L-N. Netter Q. Scally M. Wilkinson 《Knowledge, Technology, and Policy》1990,3(3):58-66
Current discussions on the utilization of information technologies for agriculture, place emphasis on the collection and processing
of information on the farm, through the introduction and use of computers as management support in process control and database
management. However, because of farm management's dependency on outside information support for the production control and
market engagement, the communication of information and the improvement of its efficiency is of similar, if not greater, importance.
This article, therefore, places its main focus on the communication aspect. It provides a classification for “on-farm” communication
patterns and highlights, using this classification, a number of European experiences with videotex applications in agriculture.
It argues that new information technologies may open the way for new approaches to farm-related communication, and thus for
a major change in farm management practices. For this progression to occur, its development and application should base itself
upon the basic communication patterns that have evolved in practice, and reflect the actual use of information in agriculture.
Mark Wilkinson is a cereal grower. He is editor of the Irish Farmers Association's closed user group, which was established
on Agriline, a Videotex system. 相似文献