全文获取类型
收费全文 | 93篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
101篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 11篇 |
2015年 | 35篇 |
2014年 | 13篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2009年 | 2篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1997年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有101条查询结果,搜索用时 15 毫秒
1.
2.
3.
Heteranassa Smith (Erebidae, Omopterini), native to the southwestern United States and Mexico, includes two recognized species, namely Heteranassa
mima (Harvey) and Heteranassa
fraterna Smith. These are separated mainly by subtle differences in wing color and pattern, leading to speculation about the validity of the described species. This study examines variation in external and internal morphology across the geographic range of the genus, aiming to clarify species limits, describe morphology, and provide a comprehensive assessment of variation within the genus. Results indicate that Heteranassa
fraterna
syn. n., is a junior synonym of Heteranassa
mima. 相似文献
4.
Federico A. Agrain Matthew L. Buffington Caroline S. Chaboo Maria L. Chamorro Matthias Sch?ller 《ZooKeys》2015,(547):133-164
Although some species of Cryptocephalinae (Coleoptera: Chrysomelidae) have been documented with ants (Hymenoptera: Formicidae) for almost 200 years, information on this association is fragmentary. This contribution synthesizes extant literature and analysizes the data for biological patterns. Myrmecophily is more common in the tribe Clytrini than in Cryptocephalini, but not documented for Fulcidacini or the closely-related Lamprosomatinae. Myrmecophilous cryptocephalines (34 species in 14 genera) primarily live among formicine and myrmecines ants as hosts. These two ant lineages are putative sister-groups, with their root-node dated to between 77–90 mya. In the New World tropics, the relatively recent radiation of ants from moist forests to more xeric ecosystems might have propelled the association of cryptocephalines and ant nests. Literature records suggest that the defensive behavioral profile or chemical profile (or both) of these ants has been exploited by cryptocephalines. Another pattern appears to be that specialized natural enemies, especially parasitoid Hymenoptera, exploit cryptocephaline beetles inside the ant nests. With the extant data at hand, based on the minimum age of a fossil larva dated to 45 mya, we can infer that the origin of cryptocephaline myrmecophily could have arisen within the Upper Cretaceous or later. It remains unknown how many times myrmecophily has appeared, or how old is the behavior. This uncertainty is compounded by incongruent hypotheses about the origins of Chrysomelidae and angiosperm-associated lineages of cryptocephalines. Living with ants offers multiple advantages that might have aided the colonization of xeric environments by some cryptocephaline species. 相似文献
5.
The Chinese species of the genera Omicrogiton Orchymont, 1919, Peratogonus Sharp, 1884 and Mircogioton Orchymont, 1937 are reviewed, diagnosed and keyed. Mircogioton and Omicrogiton are reported for the first time from China, Peratogonus for the first time for mainland China. Five species are recognized: Omicrogiton
coomani Balfour-Browne, 1939 (Guangdong, Hongkong), Omicrogiton
hainanensis
sp. n. (Hainan), Omicrogiton
roberti
sp. n. (Hainan), Mircogioton
coomani Orchymont, 1937 (Yunnan), and Peratogonus
reversus Sharp, 1884 (Guangdong, Jiangxi, Taiwan). Lectotype of Omicrogiton
coomani is designated. Mircogioton
cognitus (Malcolm, 1981), syn. n. is considered a junior subjective synonym of Mircogioton
coomani Orchymont, 1939. Species of Mircogioton and Omicrogiton inhabit decaying banana trunks, whereas Peratogonus
reversus was always collected from moist forest leaf litter. 相似文献
6.
7.
There are four species of Gymnetron in China recorded to date including Gymnetron
miyoshii Miyoshi, 1922, Gymnetron
villosipenne Roelofs, 1875, Gymnetron
auliense Reitter, 1907 and Gymnetron
vittipenne Marseul, 1876, of which the last two are new country records. The pre-imaginal stages including eggs, mature larvae and pupae of Gymnetron
miyoshii, Gymnetron
auliense and Gymnetron
vittipenne are described and illustrated. In addition, their diagnostic characters (larvae and pupae) are discussed and differentiated, and notes on some of their biological parameters are provided. Potential ecological impacts between Gymnetron weevils and their host Veronica spp. also are provided. 相似文献
8.
Our review recognizes 15 species of the integripennis species group of Geocharidius from Nuclear Central America, include three species previously described (Geocharidius
gimlii Erwin, Geocharidius
integripennis (Bates) and Geocharidius
zullinii Vigna Taglianti) and 12 described here as new. They are: Geocharidius
andersoni
sp. n. (type locality: Chiapas, Chiapas Highlands, Cerro Huitepec) and Geocharidius
vignatagliantii
sp. n. (type locality: Chiapas, Motozintla, Sierra Madre de Chiapas, Benito Juárez) from Mexico; Geocharidius
antigua
sp. n. (type locality: Sacatepéquez, 5 km SE of Antigua), Geocharidius
balini
sp. n. (type locality: Suchitepéquez, 4 km S of Volcan Atitlán), Geocharidius
erwini
sp. n. (type locality: Quiché Department, 7 km NE of Los Encuentros), Geocharidius
jalapensis
sp. n. (type locality: Jalapa Department, 4 km E of Mataquescuintla), Geocharidius
longinoi, sp. n. (type locality: El Progreso Department, Cerro Pinalón), and Geocharidius
minimus
sp. n. (type locality: Sacatepéquez Department, 5 km SE of Antigua) from Guatemala; and Geocharidius
celaquensis
sp. n. (type locality: Lempira Department, Celaque National Park), Geocharidius
comayaguanus
sp. n. (type locality: Comayagua Department, 18 km ENE of Comayagua), Geocharidius
disjunctus
sp. n. (type locality: Francisco Morazán, La Tigra National Park), and Geocharidius
lencanus
sp. n. (type locality: Lempira Department, Celaque National Park) from Honduras. For all members of the group, adult structural characters, including male and female genitalia, are described, and a taxonomic key for all members of the integripennis species group is presented based on these characters. Behavioral and biogeographical aspects of speciation in the group are discussed, based on the morphological analysis. In all cases of sympatry, pairs of closely related species show greater differences in sizes than pairs of more remotely related species. Integripennis group species occupy six different montane areas at elevations above 1300m, with no species shared among them. Major faunal barriers in the region limiting present species distributions include the Motagua Fault Zone and a gap between the Guatemalan Cordillera volcanic chain and the Honduran Interior Highlands no higher than 900m in elevation. Highest species diversity is in the Guatematan Cordillera (six species), second highest in the Honduran Interior Highlands area (four species). 相似文献
9.
《Grana》2012,51(6):408-423
AbstractIn Euphorbiaceae tribe Hippomaneae is the pantropical genus Microstachys, comprised by 24 species, mostly from Brazil. Palynological studies with several representatives of the genus are scarce. The purpose of this study was to describe the pollen morphology of Microstachys and find possible differentiating characteristics between its species. Ten species of the genus were analysed, represented by 21 herbarium collections. Their pollen grains were acetolysed, measured and photographed under light microscopy (LM) and scanning electron microscopy (SEM). The analysed species possess pollen in monads, of small to medium size, isopolars, amb distincticly trilobed, oblate-spheroidal, prolate-spheroidal or subprolate, tricolporate with narrow and very long colpi, almost fused at the poles sometimes forming an invagination with tapering ends and margo of the colporus wide to very wide and psilate; endoapertures lalongate to very lalongate with tapering ends, presence of a narrow costae distinct in the endoaperture; exine microreticulate homobrochate, walls with simple columella; at the mesocolpus the sexine separates from the nexine forming cavea; and sexine always thicker than the nexine. Microstachys is a stenopalynous genus, despite its species varying in pollen size, shape and width of the cavea, margo of the colporus, and length of the endoapertures, demonstrating taxonomic value, and indicating a contribution towards future systematic analyses. 相似文献
10.