全文获取类型
收费全文 | 107篇 |
免费 | 10篇 |
国内免费 | 16篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 11篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有133条查询结果,搜索用时 46 毫秒
51.
冬小麦水肥产量交互效应模拟研究 总被引:6,自引:0,他引:6
采用人工控制土壤含水量的方法,对冬小麦水肥产量的交互效应研究结果表明,增加施肥量可提高冬小麦对土壤水利用程度。但低供水高施肥和高供水低施肥土壤水分的无效消耗增加,不利于提高水分生产效率。要获得理想产量必须量水施肥,才能提高水分生产效率。 相似文献
52.
Charles Fernando dos Santos Flávio de Oliveira Francisco Vera Lucia Imperatriz‐Fonseca Maria Cristina Arias 《Entomologia Experimentalis et Applicata》2016,158(3):320-326
Male insects mostly aggregate near sites where sexually reproductive virgin females are found and where mating occur. This reproductive strategy is quite common in Hymenoptera and appears to decrease the chances of inbreeding. In Hymenoptera, inbred mating frequently result in sterile diploid males. Production of diploid males may reach high proportions in small bee populations, and it usually lead to population extinction within a small number of generations. Aggregation of males during a short period of time allow the mixing of local genes. In this paper, we analyzed male aggregations of Tetragonisca angustula (Latreille) (Hymenoptera: Apidae), a eusocial stingless bee, using microsatellite molecular markers. We used population genetic statistics for haplodiploid organisms to address genetic structuring among male aggregations. Our findings indicate that, in general, male aggregations of T. angustula occurring over short time scales and in close proximity are genetically homogeneous as if a single aggregation. We conclude that T. angustula males randomly disperse within a population looking for mating chances rather than settle on a distinct male aggregation. This behavior seems to contribute to the reduction of inbreeding in this species. 相似文献
53.
Bacterial community dynamics in long‐term operation of a pilot plant using aerobic granular sludge to treat pig slurry
下载免费PDF全文
![点击此处可从《Biotechnology progress》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Fra‐Vázquez N. Morales M. Figueroa A. Val del Río L. Regueiro J.L. Campos A. Mosquera‐Corral 《Biotechnology progress》2016,32(5):1212-1221
Aerobic granular sludge represents an interesting approach for simultaneous organic matter and nitrogen removal in wastewater treatment plants. However, the information about microbial communities in aerobic granular systems dealing with industrial wastewater like pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale plant using aerobic granular sludge for organic matter and nitrogen elimination from swine slurry during more than 300 days. Results indicated that bacterial composition evolved throughout the operational period from flocculent activated sludge, used as inoculum, to mature aerobic granules. Bacterial diversity increased at the beginning of the granulation process and then declined due to the application of transient organic matter and nitrogen loads. The operational conditions of the pilot plant and the degree of granulation determined the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera were attributed with structural function as they are able to produce extracellular polymeric substances to maintain the granular structure. Nitrogen removal was justified by partial nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas was identified as the main organic matter oxidizing bacteria. Overall, clear links between bacterial dynamics and composition with process performance were found and will help to predict their biological functions in wastewater ecosystems improving the future control of the process. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1212–1221, 2016 相似文献
54.
Litterfall and nutrient dynamics shift in tropical forest restoration sites after a decade of recovery
下载免费PDF全文
![点击此处可从《Biotropica》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Oscar Lanuza Fernando Casanoves Rakan A. Zahawi Danielle Celentano Diego Delgado Karen D. Holl 《Biotropica》2018,50(3):491-498
Multi‐year studies comparing changes in litterfall biomass and nutrient inputs in sites under different restoration practices are lacking. We evaluated litterfall dynamics and nutrient inputs at 5 yr and after a decade of recovery in four treatments (natural regeneration—no planting, plantation—entire area planted, tree islands—planting in patches, and reference forest) at multiple sites in an agricultural landscape in southern Costa Rica. We inter‐planted two native species (Terminalia amazonia and Vochysia guatemalensis) and two naturalized N‐fixing species (Inga edulis and Erythrina poeppigiana) in plantation and island treatments. Although litterfall N was higher in plantations in the first sampling period, litter production and overall inputs of C, N, Ca, Mg, P, Cu, Mn, and Fe did not differ between island, plantation, or reference forest after a decade; however, all were greater than in natural regeneration. Potassium inputs were lower in the natural regeneration, intermediate in island and plantation, and greater in reference forest. The percentage of litterfall comprised by the N‐fixing planted species declined by nearly two‐thirds in both plantations and islands between sampling periods, while the percentage of V. guatemalensis more than doubled, and the percentage from naturally regenerated species increased from 27 to 47 percent in islands. Island and plantation treatments were equally effective at restoring litterfall and nutrient inputs to levels similar to the reference system. The nutrient input changed substantially over the 7‐yr interval between measurements, reflecting shifts in vegetation composition and demonstrating how rapidly nutrient cycling dynamics can change in recovering forests. 相似文献
55.
Joseph V. Brady 《Applied psychophysiology and biofeedback》1989,14(3):185-193
There is basis for concern that applied psychophysiology, if not the field of biofeedback, is being coopted by, and merged into, a reborn inner model, with the return of cognition to preeminence in the psych and neuro disciplines. Despite currently fashionable views that such mentalistic inventions and neuro/psychological developments somehow illuminate behavior or offer simpler accounts of behavioral facts, there is little or no evidence that any such construction has ever told us anything new about behavior.Preparation of this article was supported in part by the following PHHS Grants: NHLBI HL 34034, NIDA DA 03476, NIDA DA 04130, NIDA DA 02490, NIDA DA 04133, NIDA DA 01147, NIDA DA 04731, and NIDA contract 271-86-8113. 相似文献
56.
John J. Furedy 《Applied psychophysiology and biofeedback》2009,34(3):149-160
In this interpretative paper, I consider four sets of methodological issues that may be relevant to improving the concealed
information test (CIT) as an instrument of applied differential psychophysiology. The first set has to do with psychophysiological
measurement in the CIT (e.g., specific sensitivity testing in lab vs. field). Secondly, I consider the relationships between
the psychological process of deception and the CIT. Thirdly, I consider the problem of laboratory-to-field generalization
of the CIT, a consideration that includes a discussion of whether the lab/field differences are merely quantitative or actually
qualitative. Finally, I discuss theories concerning the hypothetical mechanisms underlying the CIT, and argue that while the
purely cognitive, Sokolovian, orienting response (OR) account is widely accepted as the sole mechanism, there is evidence
to suggest that not just motivational, but even emotional mechanisms are also relevant.
相似文献
John J. FuredyEmail: URL: www.psych.utoronto.ca/~furedy |
57.
Yan-Song Ma Wen-Hui Wang Li-Xia Wang Feng-Ming Ma Pei-Wu Wang Ru-Zhen Chang Li-Juan Qiu 《植物学报(英文版)》2006,48(6):722-731
Soybean cyst nematode (SCN; Heterodera glycines) Is one of the most Important pests affecting soybean production. The best method of control of SCN is through the development of resistant cultlvars. However, limited progress has been made in soybean breeding In China because most modern cultlvars have no resistance to SCN. The distribution and phenotype of 432 immune or highly resistant Chinese accessions were surveyed and a primary core collection was selected as a representative sample for further analyses. Using evenly distributed simple sequence repeat markers, five selection methods were applied to the primary core collection and the optimal method was chosen to establish a core collection, which consisted of 28 accessions. These encompassed 70.8% of the ailelic variation present in the overall resistant collection. The 28 accessions differed from the reference resistant accessions at the genomlc level, Indicating that Chinese resistant accessions are distinct from known resistant accessions. This applied core collection provides a rational framework for undertaking diversity surveys, using genetic variation for the investigation of complex traits and for the discovery of novel traits. 相似文献
58.
Hannah P. Wellman Rita M. Austin Nihan D. Dagtas Madonna L. Moss Torben C. Rick Courtney A. Hofman 《Proceedings. Biological sciences / The Royal Society》2020,287(1940)
Genetic analyses are an important contribution to wildlife reintroductions, particularly in the modern context of extirpations and ecological destruction. To address the complex historical ecology of the sea otter (Enhydra lutris) and its failed 1970s reintroduction to coastal Oregon, we compared mitochondrial genomes of pre-extirpation Oregon sea otters to extant and historical populations across the range. We sequenced, to our knowledge, the first complete ancient mitogenomes from archaeological Oregon sea otter dentine and historical sea otter dental calculus. Archaeological Oregon sea otters (n = 20) represent 10 haplotypes, which cluster with haplotypes from Alaska, Washington and British Columbia, and exhibit a clear division from California haplotypes. Our results suggest that extant northern populations are appropriate for future reintroduction efforts. This project demonstrates the feasibility of mitogenome capture and sequencing from non-human dental calculus and the diverse applications of ancient DNA analyses to pressing ecological and conservation topics and the management of at-risk/extirpated species. 相似文献
59.
基于一流专业建设的应用型示范课程改革与实践:以“临床微生物学检验”课程为例 总被引:1,自引:1,他引:0
“双一流”建设的核心是培养一流人才,课程是人才培养的核心要素。应用型示范课程建设是地方普通高等学校培养应用型人才的重要举措,其建设水平直接影响着人才培养的质量。本文以成都医学院“临床微生物学检验”课程为例,围绕课程目标、课程内容、教学手段、课程考核等几个方面介绍了课程的改革与实践。这些改革在教学上更加注重专业知识、实践能力、创新能力、人文素养的培养,突显高素质临床微生物检验应用型人才的培养目标。本课程经过多年的改革与发展,已形成了具有一定特色的医学课程体系,可为地方医学院校应用型示范课程的建设提供参考和借鉴。 相似文献
60.
Abstract Wild deer are used to illustrate the conflicts that arise when an animal is both a pest and a valued resource. At present there are c. 250 000 wild deer in New Zealand. These are pursued by c. 37 000 hunters who spend more than $20 million annually to harvest c. 70 000 deer. Nearly two-thirds of the harvest is taken by recreational hunters; the remainder forms the basis of a small industry for venison export. Despite their recreational and commercial value, wild deer continue to be a significant conservation pest. Conservationists generally would like wild deer to be eradicated, or, failing that, their densities held at the lowest levels possible with the control resources available. Hunters, however, would like deer to remain, and at higher rather than lower densities, to provide better prospects for hunting success. We discuss ways in which these apparently incompatible aspirations can be partially reconciled. 相似文献