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Search Results: 1 - 10 of 102688 matches for " 葛林虎 "
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近300年来中国森林的变迁
何凡能,全胜,戴君,珊珊
地理学报 , 2007, DOI: 10.11821/xb200701004
Abstract: 以清代以来史料为依据,在现代清查统计资料和前人研究成果的基础上,通过对森林变迁大体趋势及主要过程的客观把握,重新校订了1949年和1700年前人的估算数据,回溯估算了1750~1900年中国各省区每50年森林面积与森林覆被率值,并与现代森林清查资料衔接,分析1700~1998年近300年来中国森林变迁的时空特征。结果表明近300年来中国现境内共减少森林面积约0.95×108ha,森林覆被率减少9.2个百分点,变化曲线呈先抑后仰;以1960s为界,此前呈加速递减态势,260年间减少森林面积达1.66×108hm2,覆被率下降约17个百分点;1960s以后呈逐步增长态势,近40年间增加森林面积约0.7×108hm2,覆被率提高了约8个百分点。结果还表明近300年来中国森林消长,西部地区均小于东部地区;在1700~1949年的锐减期中,东北、西南和东南三区是森林面积缩减最为严重的地方,大部分省区覆被率下降超过20个百分点,其中黑龙江达50个百分点,吉林达36个百分点,川渝地区达42个百分点,云南达35个百分点;在1949~1998年的恢复期中,西部各省区森林覆被率增加均小于5个百分点,东部地区(除黑龙江、湖北和沪宁外)均超过5个百分点;其中粤琼、广西、安徽、京津冀、山东、河南、浙江、福建等省区高达10个百分点以上。
非编码RNA在舌鳞状细胞癌中的研究进展
Research progress on non-coding RNAs in tongue squamous cell carcinoma

王丽萍,查骏,
- , 2018, DOI: 10.7518/gjkq.2018.04.009
Abstract: 摘要: 随着整个基因组学和转录组学测序技术的发展,非编码RNA(ncRNA)越来越受到关注。大量研究发现,ncRNA可以通过对染色体重构、转录和转录后翻译等生物学进程来调节基因的表达,并且这些异常表达的ncRNA与人类多种疾病(例如肿瘤)的发生、发展联系十分紧密。ncRNA逐渐成为肿瘤研究中诊断和预后的新型生物学标记和靶向治疗策略。ncRNA在人的舌鳞状细胞癌中也发挥着重要的作用,本文对ncRNA在舌鳞状细胞癌中的研究进展进行综述。
Abstract: As the development of genomics and transcriptomics, non-coding RNAs (ncRNAs) have been paid much attention. Previous studies have suggested that ncRNAs could regulate gene expression through several biological processes such as chromosome remodeling, transcription, and posttranscription translation. Abnormal versions of ncRNAs are closely related to several human diseases such as the generation and development of tumors. Therefore, ncRNAs may become novel biomarkers in the diagnosis, prognosis and target therapies of tumor research. As the essential role of ncRNAs playing in tongue squamous cell carcinoma (TSCC), the latest domestic and foreign literatures in TSCC progression were reviewed in this article.
中图分类号
荷兰口腔医学教育及口腔医学人才的培养模式

江千舟, 樊明文,
- , 2015,
Abstract:
Quantitative Analysis on For est Dynamics of China in Recent 300 Years
近300 年来中国森林的变迁

HE Fanneng,GE Quansheng,DAI Junhu,LIN Shanshan,
何凡能
,全胜,戴君,珊珊

地理学报 , 2007,
Abstract: Based on historical documents, modern survey and statistics, as well as the result of predecessor studies, the trend and main process of forest dynamics are recognized. The forest area and forest coverage rates for each province of China from 1700 to 1949 are estimated backward by every 50 years. Linking the result with modern National Forest Inventory data, the spatial-temporal dynamics of Chinese forest in recent 300 years (A.D.1700-1998) is quantitatively analyzed. The study shows that in recent 300 years, the forest area in current territory of China has declined 0.95 ×108 ha (or 9.2 percentage points of coverage rate) in total, with a trend of decrease and recovery. Before the 1960s, there was a trend of accelerated descending. The forest area was reduced 1.66×108 ha (or 17 percentage points of coverage rate) in 260 years. While after the 1960s, there has been a rapid increase. The forest area increased by 0.7×108 ha (or 8 percentage points of coverage rate) in 40 years. The study also shows that there is a significant spatial difference in the dynamics of forest. The amplitudes of increasing and decreasing in western China are both smaller than the ones in eastern China. During the rapid declining period 1700-1949, the most decrease appeared in the Northeast, the Southwest and the Southeast, where the coverage rate in most provinces dropped over 20 percentage points. In Heilongjiang Province, the coverage rate dropped 50 points. In Jilin Province, it dropped 36 points. In Sichuan Province and Chongqing Municipality, it dropped 42 points. In Yunnan Province, it dropped 35 points. During the recovery period 1949-1998, the western provinces, municipality and autonomous regions, including Ningxia, Gansu, Inner Mongolia, Sichuan-Chongqing, Yunnan, Tibet, Xinjiang and Qinghai, etc., the increase rates of the coverage are all below 5 percentage points, while the eastern provinces, municipality and autonomous regions (except Heilongjiang, Hubei and Jiangsu-Shanghai) have achieved an increase over 5 percentage points, among which the Guangdong-Hainan, Guangxi, Anhui, Beijing-Tianjin-Hebei, Shandong, Henan, Zhejiang and Fujian have an increase over 10 points.
多生牙的研究进展
A Review on Research of Supernumerary Tooth

彭博, 曾素娟,
PENG Bo
, ZENG Su-juan, GE Lin-hu

- , 2018, DOI: 10.13701/j.cnki.kqyxyj.2018.02.025
Abstract: 摘要 牙齿发育异常是一种常见的发育异常, 包括牙齿萌出与脱落异常、牙齿形态异常、牙齿数目异常及牙齿结构异常。多生牙又称额外牙,属牙齿发育异常中的数目异常,是指多于正常牙类、牙数以外的牙齿。临床上可见多种形态,包括锥形、结节型、补充型和牙瘤型等。研究报道显示多生牙在恒牙列的发生率高于在乳牙列的发生率,且男性多发。多生牙会影响口腔颌面、牙弓的发育,引起牙齿阻生,牙齿迟萌,异位萌出,牙囊形成,牙根弯曲及畸形,牙列拥挤等并发症,并且与颅骨锁骨发育不全,Gardner综合征,唇腭裂等多种综合征有关。国内外众多学者都对多生牙做了相关的研究报道,本文就多生牙的病因、临床表现、诊断与治疗、相关疾病与基因做一综述
刑法教材建设又一新成果

中外法学 , 1995,
Abstract:
单肺移植治疗终末期肺气肿
徐鑫何建行陈汉章肖东殷伟强韦兵刘君成向阳邱源
南方医科大学学报 , 2008,
Abstract:
浙混煤燃烧及no释放特性试验研究
振敏,王智化,刘敬,立超,张彦威,章勤,周俊,岑可法
热力发电 , 2014,
Abstract: 某电厂对420t/h锅炉进行了低nox燃烧器改造,为此对改造用浙混煤的燃烧和no释放特性进行了机理性研究。结果表明:不同升温速率下,污染物气体的释放特性基本相同,提高升温速率有利于提高煤样的反应活性,燃烧特性有所改善,但会造成燃烧过程滞后,no2的析出提前;随着沉降炉过量空气系数α的增大,浙混煤的no排放浓度显著增加,α在0.8~1.2时其影响最为显著;随着燃烧温度的增加,无论在氧化性气氛还是还原性气氛下浙混煤no排放浓度均增大,而且在氧化性气氛下增长幅度更大。
20世纪前、中期中国农林土地利用变化及驱动因素分析
全胜,戴君
中国科学 地球科学 中国科学 地球科学 , 2005,
Abstract: ?综合采集20世纪前、中期全国多种宝贵的土地利用数据,特别是早期的一些土地利用资料,利用聚类分析方法将中国大陆部分省区按土地利用变化差异分为7个区:东北区、华北区、西北及黄土高原区、东南沿海区、西南区、青藏高原区和蒙新区,分别对各区的农林土地利用,即耕地、林地的时空变化进行了分析.结果表明,大部分地区耕地面积有较为明显的增加趋势,20世纪50~60年代,各区的耕地面积增加较多,最大年增长率为2.63%,区域差异较大;20世纪前、中期林地面积以1949年为界,此前总体下降、此后有一定的增加趋势.有林地面积也呈现比较明显的区域差别,70年代后期多数地区林地面积减小严重.20世纪前、中期土地利用变化是自然和社会经济条件综合作用的结果,但是人口增加、粮食生产、政府政策变更等社会经济因素的影响更大,自然灾害也是土地利用变化的重要因素.
On Editing English Titles of Sci-tech Papers
科技论文英文题名的编辑加工

ZHU Dan,LI JiaLin,HE HongYing,ZHONG ShengXian,LIU DongYu,GE Liang,SUN ErHu,
朱丹
,李家,何洪英,钟盛先,刘东渝,,孙二

中国科技期刊研究 , 2007,
Abstract: 科技论文题名是用最简洁,最恰当的词语反映文章的特定内容,使读者首先明确论文研究的主题。结合编辑在修改英译题名时常遇见的几种情况,着眼英文题名的特点,详细阐述编辑英译题名时应遵循的几个规律。
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