Results 21 to 30 of about 508,186 (164)

Uncovering correlates of decline and critical refuges for a threatened terrestrial mammal

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Globally, the geographic ranges of numerous species are contracting. Identifying spatiotemporal patterns of threat impact can illuminate why species decline in some parts of their range but persist in others. We developed a correlative approach to identify species’ response thresholds and locate ecological refuge areas associated with ...
Natalya M. Maitz   +5 more
wiley   +1 more source

Measuring maternal line selection driven by differential survival in ex situ collections for plant conservation

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Ex situ plant collections may be increasingly needed to protect representative samples of threatened or rare species and provide plant material for conservation translocation. A primary problem in these ex situ collections is loss of intraspecific variation due to plant death. Different management actions would be required depending on whether
Rebecca Sucher   +6 more
wiley   +1 more source

超声引导下宫腔内胚胎移植术的临床观察

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2006
【目的】研究腹部超声引导下胚胎移植对体外受精-胚胎移植结局的影响。【方法】回顾性分析2001年7月至2005年3月,在本中心接受体外受精-胚胎移植(包括卵母细胞内单精子注射)治疗的461名患者521个周期的资料,按照胚胎移植时有无B超引导分为常规胚胎移植组(A组)和超声引导下胚胎移植组(B组),分别有187个周期和334个周期,比较两组患者的临床妊娠率、胚胎种植率、胚胎残留率和异位妊娠率。【结果】A组和B组的周期妊娠率分别是35.8%(67/187)和38.3%(128/334),P〉0.05 ...
张清学   +9 more
doaj  

Leaf C:P ratio as a universal indicator of photosynthesis in subtropical woody species: Stoichiometric thresholds and metabolic trade‐offs

open access: yesFunctional Ecology, Volume 40, Issue 7, Page 2332-2344, July 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract The stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) serve as important indicators for assessing nutrient balance in forest ecosystems, but their relationships with photosynthetic dynamics require deeper characterization.
Minghao Chen   +9 more
wiley   +1 more source

HA和 Ti 等离子喷涂种植体修复 5 年后的临床效果

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2002
【目的】评价羟基磷灰石(HA)和 Ti 等离子喷涂种植体修复 5 年后的临床效果。【方法】在 31 例患者同颌两侧的单牙缺失区,分 别植入 BLB 系统 HA 和 Ti 等离子喷涂种植体各 31 颗, 4~ 6 个月后进行烤瓷单冠修复。修复后 5 年内定期复查。【结果】BLB系统两种不同 表面喷涂种植体修复 5 年后,总累积成功率为91. 9%,其中 HA 等离子喷涂种植体组累积成功率为 96. 7%, Ti 等离子喷涂种植体组累积成功 率为86. 7%,两者之间差异不具统计学意义(P >0. 05)。【
程永喜   +3 more
doaj  

Prolonged Nutrient Enrichment Slows the Recovery of Biodiversity and Productivity After Its Cessation

open access: yesGlobal Change Biology, Volume 32, Issue 7, July 2026.
Grassland recovery following nutrient cessation is asymmetric and strongly shaped by nutrient enrichment history. Higher nutrient addition rates and longer enrichment duration caused larger departures from control conditions, with biomass recovering more rapidly than species richness over decadal timescales.
Miao He   +8 more
wiley   +1 more source

两种植骨材料促进即刻种植体周骨组织再生效果比较

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2007
【目的】比较两种植骨材料PepGen P15 Flow(简称P15)和Bio-Oss引导即刻种植体周骨组织再生能力及骨一种植体结合能力。【方法】将beagle犬下颌单侧双尖牙全部拔除,然后在新鲜拔牙窝内植入种植体3颗。植入后于种植体颊侧制备标准骨缺损并作如下处置:A组空置,B组植入P15,C组植入Bio-Oss;覆盖Bio-Gide,初期缝合伤口。于术后第6周、12周将beagle犬分期处死获取标本,进行大体、影像学、组织学观测。【结果】B、C组植骨区外形均较A组膨隆,尤其是C组。X线观察可见B ...
邓飞龙   +5 more
doaj  

宽垄沟播种植模式对夏玉米生长发育及水分利用率的影响

open access: yesShuitu Baochi Xuebao, 2019
探讨水地条件下种植模式对夏玉米产量及水分利用的影响,为夏玉米节水种植高产稳产栽培提供依据。以玉米品种"登海685"为试验材料,研究宽垄沟播和等行距平播模式下不同种植密度(6.00,6.75,7.50万株/hm2)对夏玉米生长发育、产量、养分吸收及水分利用率的影响。结果表明:沟播种植模式较平播增加玉米植株株高,使茎粗和单株干物质重降低。沟播模式的穗性状比平播处理较优,单穗重增加,且受种植密度影响较小,表现出明显的边行优势。沟播模式的玉米叶片叶绿素相对含量始终高于平播处理,生育期延长 ...
董飞   +9 more
doaj  

种植体直径对天然牙-牙种植体联合桥应力影响

open access: yesZhongguo shiyan zhenduanxue, 2012
种植义齿修复伴随基础理论和临床技术的建立,已成为一项成熟的技术逐渐推广普及。1986年基于骨性结合理论,Branemark小组成员之一即Albrektsson提出了新的种植义齿成功率的标准,即5年成功率不低于85%,10年成功率不低于80 ...
雷鸣
doaj  

GnRH激动剂长方案与GnRH拮抗剂方案在不同年龄组、不同反应人群中的新鲜周期临床结局比较

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2017
目的】比较促性腺激素释放激素激动剂(GnRH-a)长方案和促性腺激素释放激素拮抗剂(GnRH-ant)方案在 不同年龄组和不同反应人群中行体外受精或单精子卵胞浆内注射-胚胎移植(IVF/ICSI-ET)新鲜周期移植的临床结局。 【方法】回顾性分析中山大学附属第三医院生殖医学中心2015年8月28日至2016年12月31日行IVF/ICSI的737个周期,其 中GnRH-a长方案(A组)386个周期,GnRH-ant方案(B组)351个周期。按年龄和获卵数分成a和b两个亚组:a1组(< 38 岁),
朱洁茹   +3 more
doaj  

Home - About - Disclaimer - Privacy