全文获取类型
收费全文 | 593篇 |
免费 | 61篇 |
国内免费 | 25篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 23篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 22篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 26篇 |
2012年 | 21篇 |
2011年 | 32篇 |
2010年 | 29篇 |
2009年 | 52篇 |
2008年 | 46篇 |
2007年 | 45篇 |
2006年 | 26篇 |
2005年 | 27篇 |
2004年 | 23篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 17篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有679条查询结果,搜索用时 15 毫秒
1.
Christophe Y. Fischer Claire Detrain Philippe Thonart Eric Haubruge Frédéric Francis François J. Verheggen Georges C. Lognay 《Insect Science》2017,24(2):278-284
Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate‐rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two‐way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. 相似文献
2.
3.
Characterizing and predicting species distributions across environments and scales: Argentine ant occurrences in the eye of the beholder 总被引:1,自引:0,他引:1
Aim Species distribution models (SDMs) or, more specifically, ecological niche models (ENMs) are a useful and rapidly proliferating tool in ecology and global change biology. ENMs attempt to capture associations between a species and its environment and are often used to draw biological inferences, to predict potential occurrences in unoccupied regions and to forecast future distributions under environmental change. The accuracy of ENMs, however, hinges critically on the quality of occurrence data. ENMs often use haphazardly collected data rather than data collected across the full spectrum of existing environmental conditions. Moreover, it remains unclear how processes affecting ENM predictions operate at different spatial scales. The scale (i.e. grain size) of analysis may be dictated more by the sampling regime than by biologically meaningful processes. The aim of our study is to jointly quantify how issues relating to region and scale affect ENM predictions using an economically important and ecologically damaging invasive species, the Argentine ant (Linepithema humile). Location California, USA. Methods We analysed the relationship between sampling sufficiency, regional differences in environmental parameter space and cell size of analysis and resampling environmental layers using two independently collected sets of presence/absence data. Differences in variable importance were determined using model averaging and logistic regression. Model accuracy was measured with area under the curve (AUC) and Cohen's kappa. Results We first demonstrate that insufficient sampling of environmental parameter space can cause large errors in predicted distributions and biological interpretation. Models performed best when they were parametrized with data that sufficiently sampled environmental parameter space. Second, we show that altering the spatial grain of analysis changes the relative importance of different environmental variables. These changes apparently result from how environmental constraints and the sampling distributions of environmental variables change with spatial grain. Conclusions These findings have clear relevance for biological inference. Taken together, our results illustrate potentially general limitations for ENMs, especially when such models are used to predict species occurrences in novel environments. We offer basic methodological and conceptual guidelines for appropriate sampling and scale matching. 相似文献
4.
We developed primers for five polymorphic microsatellite loci to analyse the genetic structure of colonies in an invading Argentine ant population located in Haleakala National Park on the island of Maui, Hawaii. Microsatellite loci were isolated using both a polymerase chain reaction‐based and a cloning‐based method. With a range of 3–18 alleles and expected levels of heterozygosity of 0.46–0.77, these loci provide useful markers for the detection of colony and population structure in new or expanding populations of this species. 相似文献
5.
6.
Since some colonies of Argentine ant Linepithema humile were discovered in Japan in 1993, populations of this invasive alien ant species have been expanding their distribution.
To resolve the number of invasions and the genetic structure in the early stages of introduction, we inferred the genetic
structure and relationships among colonies from eight localities, from analyses of eight nuclear microsatellite DNA markers.
F
ST
analysis, principal component analysis and assignment test showed that at least three highly genetically differentiated groups
of Argentine ants are present in Japan. Populations from Hiroshima Bay were grouped together (Hiroshima, Hatsukaichi, Otake,
Iwakuni Central and Iwakuni Kuroiso), while those from Kobe and Yanai were both genetically distant from each other and from
the Hiroshima Bay group. Hatsukaichi and Kobe are international seaports, suggesting that the by-ship invasion occurred at
least twice. The invasion route of the Yanai population is unknown at this moment. The Aichi population was genetically distant
from that of the Hiroshima Bay group by the difference in allele frequencies, and it was plausible that the Aichi population
was introduced from the Hiroshima Bay group by human-mediated jump dispersal. 相似文献
7.
Annika S. Nelson Guillermo D. Zapata Keegan T. Sentner Kailen A. Mooney 《Ecological Entomology》2020,45(2):251-258
1. Although associative learning is widespread across animals, its ecological importance is difficult to assess because learning is rarely studied in the field, where informative cues are juxtaposed against complex backgrounds of uninformative noise. 2. Ants rely heavily on chemical cues for foraging and engage in many ecologically important interactions with plants. Nevertheless, little is known about the role of associative learning of plant chemicals in ant foraging for carbohydrates. 3. In a field setting, the present study investigated whether the distantly related ant species Formica podzolica (Formicinae subfamily) and Tapinoma sessile (Dolichoderinae subfamily) exhibited associative learning of the chemical cues from two co-occurring plant species that are taxonomically and chemically distinct (Asteraceae: Helianthella quinquenervis and Apiaceae: Ligusticum porteri). 4. For two consecutive summers, ants were trained to forage from artificial sugar-rich baits associated with the leaf chemicals from either H. quinquenervis or L. porteri for 24 h, after which a two-choice test was deployed to assess whether ants would be more likely to select baits associated with the same (versus different) plant chemicals on which they had been trained. 5. The present study demonstrates associative learning of chemicals from both plant species, and these effects were consistent between ant species and years; training increased bait occupancy from 42% on the untrained scent to 66% on the trained scent. These results indicate that associative odour-learning may be widespread across ants and serve as an important mechanism mediating ant selection of resources. 相似文献
8.
GABRIEL D. G. DEBOUT RICARDO PEREYRA BRENT C. EMERSON DOUGLAS W. YU 《Molecular ecology resources》2006,6(1):182-184
Fifteen microsatellite loci were isolated from the Peruvian tropical plant‐ant Allomerus octoarticulatus cf. demerarae (Hymenoptera: Myrmicinae) and their polymorphism was characterized. High levels of within‐population variation were observed at most loci, with number of alleles ranging from one to 21, and heterozygosity from 0 to 1 per population sample. Cross‐species amplification of these loci was also tested in one other species of the ant genus Allomerus (Allomerus decemarticulatus), displaying similar life history. 相似文献
9.
We describe the isolation and characterization of five dinucleotide microsatellite loci in the ant Myrmica scabrinodis, which were obtained using a magnetic bead hybridization selection protocol. The PCR primers were tested on nine to 11 individuals. The number of alleles ranged from two to 13, and the observed heterozygosity from 0.200 to 0.778. 相似文献
10.