首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   14篇
  免费   5篇
林业   1篇
  2篇
综合类   3篇
畜牧兽医   11篇
园艺   1篇
植物保护   1篇
  2022年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2017年   4篇
  2016年   2篇
  2014年   2篇
  2013年   2篇
  2011年   1篇
  2006年   1篇
  2004年   1篇
  2002年   1篇
  1999年   1篇
排序方式: 共有19条查询结果,搜索用时 31 毫秒
1.
Context

With underrepresentation of habitats in publicly protected areas, attention has focused on the function of alternative land conservation mechanisms. Private conservation easements (CEs) have proliferated in the United States, yet assessing landscape-level function is confounded by varying extent, resolution, and temporal scale.

Objectives

We developed and tested an assessment tool to evaluate interacting spatial, social, and environmental attributes of easements relative to the degree of human modification (HM). We hypothesized that on both private and public conservation properties HM would be lower than on non-conserved parcels, and that for fine-scale features (most CEs), the level of HM would be driven by the variables used to create the coarser scale HM measure.

Methods

Variation in HM between private, public, and non-conserved was tested via pairwise parcel sampling. Composition was evaluated using multiple geographic bounds and edge characteristics. We assessed both environmental and social predictors using multinomial logistic regression.

Results

Privately conserved lands did not differ significantly from non-conserved lands. Publicly conserved lands had lower HM than both privately conserved and non-conserved lands. Edge contrast was similar between private and matched non-conserved patches. The level of HM was not driven by distance to roads, or by elevation in this mixed-use setting.

Conclusions

Variation in tests for differences, land characteristics, and HM variables confirmed the significantly lower HM of publicly protected lands, and opens the question as to naturalness of easements in some contexts. CEs in this location may be representative of the mixed rural-forested landscape instead of more natural land cover.

  相似文献   
2.
3.
Fumigation is an important crop protection practice employed to control soil pathogens and diseases. Metham sodium and cadusafos are two commonly used soil fumigants for this purpose. However, little information is available on their effects on non-target soil organisms. The aim of the study was to determine the ecotoxicity of these chemical fumigants on earthworms (organismal responses and DNA damage) and soil microbial communities. Changes in soil microbial community function and structure were evaluated by means of Biolog? Ecoplates and phospholipid fatty acid (PLFA) analyses, respectively. Both fumigants had a significant (p < 0.05) negative impact on all earthworm endpoints. Earthworms did not reproduce; biomass was affected negatively and manifested significant DNA damage with metham sodium causing more pronounced effects in comparison to cadusafos. The fumigants had an inhibitory effect on microbial growth. No lasting effects were observed in the community structure but cadusafos had a pronounced effect on the microbial community functional diversity. Metham sodium and cadusafos had varying effects on earthworm and microbial endpoints. This illustrates the importance of using different bioindicators to get a better understanding of the overall effects on the soil ecosystem.  相似文献   
4.
5.
The lithospheric mantle beneath the Kaapvaal-Zimbabwe craton of southern Africa shows variations in seismic P-wave velocity at depths within the diamond stability field that correlate with differences in the composition of diamonds and their syngenetic inclusions. Middle Archean mantle depletion events initiated craton keel formation and early harzburgitic diamond formation. Late Archean accretionary events involving an oceanic lithosphere component stabilized the craton and contributed a younger Archean generation of eclogitic diamonds. Subsequent Proterozoic tectonic and magmatic events altered the composition of the continental lithosphere and added new lherzolitic and eclogitic diamonds to the Archean diamond suite.  相似文献   
6.
7.
8.
Four 2-month-old foals were presented to an equine hospital with acute kidney injury caused by Leptospira interrogans infection. Clinical signs were nonspecific and included lethargy, fever, and unwillingness to nurse. The most important hematologic and clinicopathologic findings were azotemia, anemia, thrombocytopenia, hyponatremia, and hypochloremia. The diagnosis was based on urinary real-time PCR, serology using a microscopic agglutination test, or both. The most important serovars involved were L. interrogans serogroup australis serovar Bratislava and Australis. Treatment consisted of IV fluid therapy and antimicrobial treatment. Renal replacement therapy with hemodiafiltration was performed in 1 of the foals. All foals survived to discharge. This report highlights the importance of early diagnosis and treatment in foals with acute kidney injury caused by L. interrogans infection.  相似文献   
9.
Transcutaneous needle decompression of the caecum through the right flank is a valuable, routine procedure performed to resolve cases of large intestinal tympany. Nevertheless, it can be the cause of potentially life‐threatening complications as highlighted by the 3 cases presented in this case report. Abscess formation, septic peritonitis and haemorrhage following needle decompression are described.  相似文献   
10.
Uittreksel

Bogrondse droë massa‐opbrengste (DM) van Medicago truncatula, cvv. Cyprus en Jemalong, M. aculeata var. inermis, cv. SA 4438, M. orbicularis, cv. SA 2552 en M. rugosa, cv. Paragosa wat op ses verskillende datums gevestig is, is in ‘n veldproef onder besproeiing bepaal. Die plantdatums was c. 15 dae gespasieer, vanaf middel Februarie tot einde April, DM is op drie stadiums bepaal naamlik drie weke na opkoms, begin blomstadium en met die aanvang van peulverkleuring toe finale DM ongeveer bereik is. Uiteindelik is peul‐ en saadopbrengs ook bepaal.

Die DM op drie weke het in alle gevalle sterk afgeneem namate later geplant is en die temperature gedaal het, terwyl die opbrengs met blom en peulverkleuring grootliks bepaal is deur die tydsverloop vanaf plant tot die betrokke stadiums. Die gemiddelde finale DM oor die ses plantings was 11,5; 10,7; 8,4; 6,7 en 5,0 t/ha vir Jamalong, SA 4438, Cyprus, Paragosa en SA 2552 onderskeidelik. Die gemiddelde saadopbrengste het gewissel van 650 kg/ha by Paragosa tot 2460 kg by SA 2552.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号