全文获取类型
收费全文 | 123篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
教育 | 75篇 |
科学研究 | 21篇 |
各国文化 | 3篇 |
体育 | 12篇 |
综合类 | 5篇 |
信息传播 | 12篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 13篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有128条查询结果,搜索用时 390 毫秒
101.
基于生态足迹理论和方法,对中国金矿资源开发利用效率与环境压力作定量研究。结果表明:1994年-2001年中国金矿石生态足迹总体呈上升趋势,但波动较大,究其原因,钢铁、木材和电力消耗是影响总量趋势变化的关键因素;研究期内单位金矿石产出的生态资源消耗量呈现下降趋势,资源效率不断提高,资源开发规模效应显现;从结构上看,能源消费是金矿石生态足迹的重要来源,但与有色及钢铁等全行业最终产品相比,初级产品金矿石的能源足迹所占比重明显较低,矿山占用地和工业品携带能源足迹在金矿石足迹结构中也占有重要的地位。研究不仅为矿产品生态足迹提供了计算框架及范式,也刻画了矿产资源开发利用中资源和生态付出的代价,或可为矿产资源开发的生态补偿政策研究提供理论依据。 相似文献
102.
难浸金矿氧化预处理方法评述 总被引:2,自引:0,他引:2
介绍了难浸金矿用焙烧法,加压氧化法和细菌氧化法预处理的原理,工业实践及几种方法的技术经济比较。 相似文献
103.
电子阅览室是现代图书馆读者阅览本地资源和搜索网络资源的主要场所,本文主要介绍了金盘电子阅览室管理系统的功能及在西藏高校图书馆中的应用情况。 相似文献
104.
Corinna Schäfer 《Cultural and Social History》2013,10(5):681-698
ABSTRACTThe entangled history of the German Colonial Press Law (written 1906–1912) begins with the wish of the German East African Governor to keep the pugnacious settler press under control. Under the influence of a racist discourse that sought to restrict education for Africans and feared anti-colonial actions and networks, the law developed into a legal basis that could impede publishing activities of the colonised in all German colonies. In Togoland, African writers bypassed such restrictions by publishing critical articles in the adjacent British Gold Coast Colony and thereby succeeded in entering transnational supportive networks. 相似文献
105.
Clare Vernon 《Al-Masaq: Islam & the Medieval Mediterranean》2019,31(1):95-110
The subject of this article is the mantle of the kings of Sicily, now in the Kunsthistorisches Museum in Vienna. Made in Palermo in the 1130s, it is often known as the mantle of Roger II. Following his coronation in 1130, King Roger II saw the need to ensure the succession of his sons. As part of his strategy to consolidate dynastic succession, Roger invested his sons with important titles in the mainland regions of the kingdom. This article has two parts: the first discusses the materials used to make the mantle, the journeys they took to reach Sicily and the diplomatic and commercial relationships necessary to acquire them. The second part argues that the mantle may have been made for the investiture ceremonies of the king’s sons and examines how the materials and their exoticism shaped the ceremonial meaning of the garment. 相似文献
106.
本文采用长春应化所研制的PVC—尼龙6树脂分离富集溶解于王水中的样品金,经亚硫酸钠洗脱液洗脱后,用原子吸收分光光度计测定,此方法操作简便,分析速度快,适用于多种类型金矿中金的分析 相似文献
107.
Zahra Saffari Maryam Farahnak Zarabi Hasan Aryapour Alireza Foroumadi Ali Farhangi Soheil Ghassemi Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2015,30(2):140-149
Chemotherapy drugs, used for prevention of uncontrolled cell proliferation in certain tissues as well as inducing apoptosis in tumor cells, are important candidates for treatment of cancer. The synthesized 2-amino-4H-chromene-3-carbonitrile derivatives effective on cancerous cells resistant to other drugs such as Paclitaxel were used due to their ability in induction of apoptosis. The growth inhibitory and inducing apoptosis activities were determined. In order to make it target-oriented, the best compound was conjugated with gold nanoparticles (NPs) by aspartic acid with chemical reduction method. Cytotoxicity effect of 2-amino-4H-chromene-3-carbonitrile derivatives against the T47D breast cancer cell line was determined by MTT assay. The synthesis of gold NPs was confirmed by transmission electron microscopy, UV–Vis and dynamic light scattering. To assess the effects of compounds on the process of apoptosis, staining methods with acridine orange–ethidium bromide and Hoechst staining by fluorescence microscopy and DNA fragmentation by the diphenylamine method were used. The synthesized compounds containing two NH2 groups on benzene rings, demonstrated more cytotoxicity effect. The effect of conjugation with gold NPs and the induction of apoptosis were studied with the best compound. The cytotoxicity effects of the synthesized 2-amino-4H-chromene-3-carbonitrile compounds were changed by replacement of NO2 group on thiol ring with different chemical groups on the benzene ring. Analyses of treated cell lines by conjugated and non-conjugated forms of compounds verified their ability in inducing apoptosis while conjugated form demonstrated higher apoptosis. 相似文献
108.
古文献中的"金"字具有多种含义,可指黄金、银、铜,乃至其他的金属。含有"金"字的词语中,只有"黄金"和"金子"可确认为一般意义上的黄金;"白金"多指白银;"赤金"早期多指铜,后期指高纯度的黄金;"黑金"则指铁。而"金"字本身的含义,主要是随着金属货币流通状况而变化。先秦时期多指铜,秦汉到宋元时期多指黄金,明清则多指银,现代则回归于黄金。联系上下文,注意文献的年代背景,是准确理解其含义的关键。 相似文献
109.
110.
利用循环伏安法(CV)和模板(阳极氧化铝模板(AAO),制备出多孔粗糙金纳米管,壳聚糖将(AAO制备所得)其固定在玻碳电极上,然后将模板溶解,制得金纳米管修饰的传感器,并将其用于抗坏血酸(AA)和尿酸(UA)的直接电化学测定。利用电子扫描电镜(SEM)分析了金纳米管的微观形貌,通过微分差示脉冲伏安(DPV)和循环伏安法考察了抗坏血酸和尿酸在修饰电极上的电化学行为。结果表明,该传感器检测抗坏血酸和尿酸的线性范围分别为1.02×10-7~5.23×10-4mol·L-1和1.43×10-7~4.64×10-4mol·L-1,检测下限分别为1.12×10-8mol·L-1和2.24×10-8mol·L-1。该传感器具有稳定性好,制作简单,使用寿命长等特点,为实际样品中抗坏血酸和尿酸的测定提供了一种新的简便手段。 相似文献