Results 51 to 60 of about 366 (78)

退化沙质草地开垦和封育对土壤理化性状的影响

open access: yesShuitu Baochi Xuebao, 2002
分析了退化沙质草地开垦耕种2年和围封恢复5年后土壤理化性状的特征和变化。结果表明:(1)开垦后2年的耕作,使0-15cm耕作层<0.1mm细颗粒组分下降了23.8%,其中0-2.5cm表层和2.5-7.5cm亚表层0.1-0.05mm的细沙损失了38.1%和27.0%,土壤的粗粒化程度已接近于流沙;土壤有机碳、全氮、全磷分别下降了38.4%,28.0%和18.4%,下降幅度随土层深度而减小,(2)围封恢复5年后,粒级分布的变化仅发生在0-2.5cm的表层土壤,极细沙(0.1-0.05mm)、粉粒(0 ...
苏永中 赵哈林 等
doaj  

和田地区主要地表类型风蚀研究

open access: yesShuitu Baochi Xuebao, 2008
为了解沙尘暴多发区和田地区主要地表类型的土壤风蚀量情况,利用集沙仪进行了中、小尺度条件下的沙尘暴实地测定,结果表明:在中尺度下,主要地表类型沙漠、过渡带和绿洲土壤输沙量、降尘量具有显著性差异,并与覆盖度存在明显的相关性。在小尺度下观测的结果表明,不同地表类型输沙量也存在显著差异,相同高度下平均覆盖度82%的农田输沙量不足沙漠输沙量的10%,沙漠观测点下风口输沙量比上风口增长2.39%,弃耕地下风口输沙量比上风口增长7.90%,而覆盖农田下风口输沙量比上风口减少2.24 ...
刘国庆   +8 more
doaj  

[Guiding opinion for infection protection in Ear & Nose & Throat Department during the outbreak of coronavirus disease]. [PDF]

open access: yesLin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi, 2020
Wuhan Medical Doctor Association of Otorhinolaryngology Head and Neck Surgery.
europepmc   +1 more source

[Primarily application of Ilizarov microcirculation reconstruction technique for chronic wounds in post-traumatic ischemia limbs]. [PDF]

open access: yesZhongguo Xiu Fu Chong Jian Wai Ke Za Zhi, 2020
Zhu Y   +7 more
europepmc   +1 more source

[Prevalence of pediatric asthma in the rural areas of China: a Meta analysis]. [PDF]

open access: yesZhongguo Dang Dai Er Ke Za Zhi, 2020
Li LX, Lin SZ, Zhang RP, Chen SW.
europepmc   +1 more source

1990—2020年滇中城市群耕地非农化时空变化特征及驱动机制

open access: yesShuitu Baochi Xuebao
[目的] 通过分析滇中城市群30年耕地非农化的演变路径、时空变化特征及驱动机制,为滇中城市群耕地资源的保护及精准管理提供理论依据。[方法] 基于滇中城市群土地利用数据和统计年鉴数据,运用重心迁移模型、变化轨迹模型、空间自相关分析、主成分分析等方法揭示1990—2020年滇中城市群耕地非农化过程、空间分布特征及主要驱动因素。[结果] (1)从时间上看,滇中城市群耕地非农化面积呈波动下降趋势,2000年前后由年均增加约6.88×103 hm2转变为年平均减少约2.66×104 hm2,受政策 ...
杨玉钱   +4 more
doaj  

[Rehabilitation guidelines and specifications for traumatic spinal cord injury (2025 edition)]. [PDF]

open access: yesZhongguo Xiu Fu Chong Jian Wai Ke Za Zhi
Professional Committee Of Spine And Spinal Cord Injury Rehabilitation China Association Of Rehabilitation Of Disabled Persons   +3 more
europepmc   +1 more source

[Advances in inhalable nano-formulations]. [PDF]

open access: yesZhejiang Da Xue Xue Bao Yi Xue Ban
Luo Y, Yue X, Zhao Z, Zhang X.
europepmc   +1 more source

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