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992.
新疆北部东天山十里坡地区近年来新发现了与玄武岩有关的自然铜矿化这一新类型。自然铜的赋矿地层-马头滩组中的赋矿玄武岩锆石LA-ICPMS年龄为307±4Ma,对应于晚石炭世,显示该套赋矿地层属于上石炭统。从该区自然铜赋矿火山岩所限定的时间看,成矿背景应属于后碰撞环境。东天山十里坡地区自然铜矿化的构造背景、成矿系统和矿化类型与峨眉山玄武岩自然铜矿化和美国基威诺铜矿床均存在差异,自然铜矿化的成因可能也存在差异。 相似文献
993.
994.
首先对大数据做简要诠释;其次重点阐述大数据在国内外各个领域的应用现状,以此来对大数据产业的发展、社会定位以及价值实现途径进行探索;最后分析我国大数据产业发展当中存在的主要问题并给出相关建议。 相似文献
995.
老年人血小板谷胱甘肽过氧化物酶的纯化和分子特性研究 总被引:1,自引:0,他引:1
报道老年人血小板谷胱甘肽过氧化物酶由SepharoseQ柱层析、MonoQHR5/5FPLC和亲和层析后,经SDS/PAGE鉴定为一条区带,其分子量为23kDa.等电聚焦测定PI为5.1.用Super-oseHR10/30柱经FPLC测定的分子量为92kDa,这表明在自然状态下血小板谷胱甘肽过氧化物酶由四个相同的亚单位组成。这些结果与人红细胞谷胱甘肽过氧化物酶的特性相一致. 相似文献
996.
讨论了美国政府管理部门如何利用加强和鼓励高质量科研的投资原则与手段来改进研发绩效,解析了美国政府科研经费划拨原则及趋势、方向. 相似文献
997.
The purpose of this study was to examine specific word- and sentence-level features most frequently used in the expository writing of four groups of college writers. Three groups were writers who demonstrated disabilities. Group 1 students (n = 87) demonstrated learning disabilities (LD); Group 2 (n = 50), attention-deficit/hyperactivity disorder (ADHD); and Group 3 (n = 58), combined LD and ADHD. Group 4 consisted of writers with no history of a documented disability (n = 92). Computer-based analysis and structural equation modeling were used to group specific linguistic features identified in the expository essays across all four groups. The frequency of linguistic features, not errors, was analyzed. Four communication dimensions (factors) were identified for the four groups of writers, but the factor loadings and correlations were significantly different across groups. Furthermore, the relationships of specific linguistic features were studied as to their impact on the verbosity, quality, and lexical complexity of students' expository essays. It is interesting to note that very high correlations were found between verbosity, quality, and lexical complexity, suggesting that these constructs are not as separate in their functioning as might be supposed. Implications for assessment and instruction are provided. 相似文献
998.
Hollich GJ Hirsh-Pasek K Golinkoff RM Brand RJ Brown E Chung HL Hennon E Rocroi C 《Monographs of the Society for Research in Child Development》2000,65(3):i-vi, 1-123
How do children learn their first words? The field of language development has been polarized by responses to this question. Explanations range from constraints/principles accounts that emphasize the importance of cognitive heuristics in language acquisition, to social-pragmatic accounts that highlight the role of parent-child interaction, to associationistic accounts that highlight the role of "dumb attentional mechanisms" in word learning. In this Monograph, an alternative to these accounts is presented: the emergentist coalition theory. A hybrid view of word learning, this theory characterizes lexical acquisition as the emergent product of multiple factors, including cognitive constraints, social-pragmatic factors, and global attentional mechanisms. The model makes three assumptions: (a) that children cull from multiple inputs available for word learning at any given time, (b) that these inputs are differentially weighted over development, and (c) that children develop emergent principles of word learning, which guide subsequent word acquisition. With few exceptions, competing accounts of the word learning process have examined children who are already veteran word learners. By focusing on the very beginnings of word learning at around 12 months of age, however, it is possible to see how social and cognitive factors are coordinated in the process of vocabulary development. After presenting a new method for investigating word learning, the development of reference is used as a test case of the theory. In 12 experiments, with children ranging in age from 12 to 25 months of age, data are described that support the emergentist coalition model. This fundamentally developmental theory posits that children construct principles of word learning. As children's word learning principles emerge and develop, the character of word learning changes over the course of the 2nd year of life. 相似文献
999.
Love JM Harrison L Sagi-Schwartz A van IJzendoorn MH Ross C Ungerer JA Raikes H Brady-Smith C Boller K Brooks-Gunn J Constantine J Kisker EE Paulsell D Chazan-Cohen R 《Child development》2003,74(4):1021-1033
Three studies examined associations between early child care and child outcomes among families different from those in the National Institute of Child Health and Human Development (NICHD) Early Child Care Research Network study. Results suggest that quality is an important influence on children's development and may be an important moderator of the amount of time in care. Thus, the generalizability of the NICHD findings may hinge on the context in which those results were obtained. These studies, conducted in three national contexts, with different regulatory climates, ranges of child care quality, and a diversity of family characteristics, suggest a need for more complete estimates of how both quality and quantity of child care may influence a range of young children's developmental outcomes. 相似文献
1000.
三藏的三个主要徒弟都达到了长生不老,并且,由一位师傅向他们传道,通过修行的过程,参加了天堂的统治集团.他们的师傅必须大大地依靠他们超自然的特性和神力,因此,不是从他们同佛教之间的联系起源的.更确切地说,这是他们在体内炼金术上的成功.当他们制作内在的、长生不老炼金药时,使孙悟空、猪悟能和沙悟净取得了充当不朽僧侣的合适卫士的资格.需要他们帮助的理由是取经活动本身被认为是充满了艰难险阻的,有了人类的助手和同伴,对于取经之行不是多余的.在第8回里,由观音菩萨受释迦牟尼的派遣,到“东土”去寻找一位去取经的圣僧,她得到了如来赠予的特殊宝物,以及送给他们保护之下的候选人.她也劝说在路上遇到的任何一个拥有巨大魔力的妖怪,成为取经朝圣的徒弟.她的中国之行基本上成了一项预期的西方之行,而事件的顺序和地理方向却部分地颠倒了.这归因于四个天堂的叛徒正在变成徒弟,因而也就为读者准备了小说中后来的发展.当玄奘后来离开长安时,很快就抛弃了他的人类助手.对于那座山,意味深长命名为“两界山”,这是在小说结构上标志着取经的圣僧离开唐代中国,从世俗的领土出发,现在已进入了旅行的神秘区域,被野兽、妖怪和恶魔所困扰.玄奘有过一位在第一难期间就当他的助手的民间猎人,他告诉玄奖:必须独 相似文献