全文获取类型
收费全文 | 938篇 |
免费 | 44篇 |
国内免费 | 115篇 |
专业分类
1097篇 |
出版年
2024年 | 7篇 |
2023年 | 29篇 |
2022年 | 56篇 |
2021年 | 26篇 |
2020年 | 36篇 |
2019年 | 42篇 |
2018年 | 29篇 |
2017年 | 32篇 |
2016年 | 50篇 |
2015年 | 70篇 |
2014年 | 101篇 |
2013年 | 131篇 |
2012年 | 63篇 |
2011年 | 79篇 |
2010年 | 34篇 |
2009年 | 19篇 |
2008年 | 31篇 |
2007年 | 33篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 20篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 11篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 29篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有1097条查询结果,搜索用时 15 毫秒
921.
Review of the genus Eusterinx Förster, 1869 (Hymenoptera: Ichneumonidae: Orthocentrinae) with descriptions of five new species from South Korea 下载免费PDF全文
South Korean species of the genus Eusterinx Förster are reviewed here. Nine species of the genus Eusterinx are found to occur in South Korea, and five species, Eusterinx (E.) elongata sp. nov. , E. (Holomeristus) hirtis sp. nov. , E. (Ischyracis) fulvipes sp. nov. , E. (I.) petiolata sp. nov. and E. (I.) rufithorax sp. nov. , are described. Four more species of Eusterinx from subgenera Divinatrix, Eusterinx and Holomeristus are recorded from South Korea for the first time. Hitherto, unknown male of the Eastern Palaearctic species E. (Divinatrix) kurilensis Humala is described. A key to all known species of the genus Eusterinx occurring in South Korea is provided. 相似文献
922.
923.
Ashea
megacephala, a new Peruvian genus and species is described. The specimens were collected on mushrooms and mushroom-associated trees. This genus can be readily distinguished from the other genera of the subtribe Gyrophaenina by the large head and the three indistinctly articulated labial palpomeres. A key to the known genera of Gyrophaenina is provided. A habitus photograph and illustrations of diagnostic characters are also presented. 相似文献
924.
Daniel P. Faith 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1662)
The phylogenetic diversity measure, (‘PD’), measures the relative feature diversity of different subsets of taxa from a phylogeny. At the level of feature diversity, PD supports the broad goal of biodiversity conservation to maintain living variation and option values. PD calculations at the level of lineages and features include those integrating probabilities of extinction, providing estimates of expected PD. This approach has known advantages over the evolutionarily distinct and globally endangered (EDGE) methods. Expected PD methods also have limitations. An alternative notion of expected diversity, expected functional trait diversity, relies on an alternative non-phylogenetic model and allows inferences of diversity at the level of functional traits. Expected PD also faces challenges in helping to address phylogenetic tipping points and worst-case PD losses. Expected PD may not choose conservation options that best avoid worst-case losses of long branches from the tree of life. We can expand the range of useful calculations based on expected PD, including methods for identifying phylogenetic key biodiversity areas. 相似文献
925.
Maxim Nabozhenko 《Zoology in the Middle East.》2013,59(1):64-68
Five species of the genus Catomus Allard, 1876 are known from Iran. Catomus fragilis (Ménétriés, 1848) is recorded from Iran for the first time. Lectotypes of C. persicus Allard, 1876 (type species of the genus) and C. semiruber Allard, 1876 are designated. These species are also redescribed and figured. A key to the species of Catomus in the Iranian fauna is given. 相似文献
926.
African species of Oxyscelio (Hymenoptera: Platygastridae s.l.) are revised. A total of 14 species are recognized, 13 of which are described as new: Oxyscelio
absentiae Burks, sp. n., Oxyscelio
galeri Burks, sp. n., Oxyscelio
gyri Burks, sp. n., Oxyscelio
idoli Burks, sp. n., Oxyscelio
intensionis Burks, sp. n., Oxyscelio
io Burks, sp. n., Oxyscelio
kylix Burks, sp. n., Oxyscelio
lunae Burks, sp. n., Oxyscelio
nemesis Burks, sp. n., Oxyscelio
pulveris Burks, sp. n., Oxyscelio
quassus Burks, sp. n., Oxyscelio
teli Burks, sp. n. and Oxyscelio
xenii Burks, sp. n. The genus Freniger Szabó, syn. n. is recognized as part of an endemic African species group of Oxyscelio with incomplete hind wing venation, and Oxyscelio
bicolor (Szabó), comb. n. is therefore recognized as the only previously described species of Oxyscelio from Africa. The Oxyscelio
crateris and Oxyscelio
cuculli species groups, previously known from southeast Asia, are represented in Africa by seven and one species respectively. 相似文献
927.
928.
Staminal evolution in the genus Salvia (Lamiaceae): molecular phylogenetic evidence for multiple origins of the staminal lever 总被引:1,自引:0,他引:1
BACKGROUND AND AIMS: The genus Salvia has traditionally included any member of the tribe Mentheae (Lamiaceae) with only two stamens and with each stamen expressing an elongate connective. The recent demonstration of the non-monophyly of the genus presents interesting implications for staminal evolution in the tribe Mentheae. In the context of a molecular phylogeny, the staminal morphology of the various lineages of Salvia and related genera is characterized and an evolutionary interpretation of staminal variation within the tribe Mentheae is presented. METHODS: Two molecular analyses are presented in order to investigate phylogenetic relationships in the tribe Mentheae and the genus Salvia. The first presents a tribal survey of the Mentheae and the second concentrates on Salvia and related genera. Schematic sketches are presented for the staminal morphology of each major lineage of Salvia and related genera. KEY RESULTS: These analyses suggest an independent origin of the staminal elongate connective on at least three different occasions within the tribe Mentheae, each time with a distinct morphology. Each independent origin of the lever mechanism shows a similar progression of staminal change from slight elongation of the connective tissue separating two fertile thecae to abortion of the posterior thecae and fusion of adjacent posterior thecae. A monophyletic lineage within the Mentheae is characterized consisting of the genera Lepechinia, Melissa, Salvia, Dorystaechas, Meriandra, Zhumeria, Perovskia and Rosmarinus. CONCLUSIONS: Based on these results the following are characterized: (1) the independent origin of the staminal lever mechanism on at least three different occasions in Salvia, (2) that Salvia is clearly polyphyletic, with five other genera intercalated within it, and (3) staminal evolution has proceeded in different ways in each of the three lineages of Salvia but has resulted in remarkably similar staminal morphologies. 相似文献
930.
Three new species and two new genera of longhorn beetles are described from Peru: Cosmoplatus polis n. sp. (Pteroplatini), Hemilocallia grishami n. gen., n. sp. (Calliini) and Arabela ramirezi n. gen., n. sp. (Hemilophini). Esmeralda laetifica Bates, 1869 (Prioninae), Stratone transversalis (Chevrolat, 1862) (Cerambycinae), Gymnocerina cratosomoides (Bates, 1862) (Lamiinae), and Trachysomus verrucosus (Olivier, 1795) (Lamiinae) are new records for Peru. 相似文献