全文获取类型
收费全文 | 77篇 |
免费 | 2篇 |
专业分类
79篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 7篇 |
2014年 | 1篇 |
2013年 | 11篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有79条查询结果,搜索用时 15 毫秒
1.
Michael D. Guiry 《Journal of phycology》2012,48(5):1057-1063
Algae have been estimated to include anything from 30,000 to more than 1 million species. An attempt is made here to arrive at a more accurate estimate using species numbers in phyla and classes included in the on‐line taxonomic database AlgaeBase ( http://www.algaebase.org ). Despite uncertainties regarding what organisms should be included as algae and what a species is in the context of the various algal phyla and classes, a conservative approach results in an estimate of 72,500 algal species, names for 44,000 of which have probably been published, and 33,248 names have been processed by AlgaeBase to date (June 2012). Some published estimates of diatom numbers are of over 200,000 species, which would result in four to five diatom species for every other algal species. Concern is expressed at the decline and potential extinction of taxonomists worldwide capable of improving and completing the necessary systematic studies. 相似文献
2.
Strains of Gracilaria foliifera (Forsskål) Børgesen isolated into culture from Ireland (where the species would appear to be introduced), England and the Atlantic coast of France were interfertile. Strains of G. foliifera from Texas and North Carolina, U.S.A. were similarly interfertile but did not cross with the European strains. The North Carolina strain was distinctly flattened in culture and superficially resembled G. foliifera from Europe whereas the Texas strain was terete or slightly flattened. Both of the American strains were interfertile with an isolate of G. tikvahiae McLa-chlan from the type locality of this species in northern Nova Scotia, Canada. It seems likely from these data that G. foliifera is not represented on the coast of North America and that G. tikvahiae is a highly morphologically variable species widely distributed from Nova Scotia south to the Caribbean. Examination of type material of Gracilaria foliifera and G. multipartita (Clemente) Harvey, together with phyto-geographical considerations, suggests that the species known as G. foliifera on eastem Atlantic masts should be known as G. rnultipartita , and that G. foliifera s. str . is probably confined to the Red, Arabian, and Indian Seas. 相似文献
3.
Michael A. Ruggiero Dennis P. Gordon Thomas M. Orrell Nicolas Bailly Thierry Bourgoin Richard C. Brusca Thomas Cavalier-Smith Michael D. Guiry Paul M. Kirk 《PloS one》2015,10(4)
We present a consensus classification of life to embrace the more than 1.6 million species already provided by more than 3,000 taxonomists’ expert opinions in a unified and coherent, hierarchically ranked system known as the Catalogue of Life (CoL). The intent of this collaborative effort is to provide a hierarchical classification serving not only the needs of the CoL’s database providers but also the diverse public-domain user community, most of whom are familiar with the Linnaean conceptual system of ordering taxon relationships. This classification is neither phylogenetic nor evolutionary but instead represents a consensus view that accommodates taxonomic choices and practical compromises among diverse expert opinions, public usages, and conflicting evidence about the boundaries between taxa and the ranks of major taxa, including kingdoms. Certain key issues, some not fully resolved, are addressed in particular. Beyond its immediate use as a management tool for the CoL and ITIS (Integrated Taxonomic Information System), it is immediately valuable as a reference for taxonomic and biodiversity research, as a tool for societal communication, and as a classificatory “backbone” for biodiversity databases, museum collections, libraries, and textbooks. Such a modern comprehensive hierarchy has not previously existed at this level of specificity. 相似文献
4.
Guiry KP Kelleher JM Lawrence SE McAuliffe MT Moynihan HA Ryan AL 《Journal of enzyme inhibition and medicinal chemistry》2007,22(5):550-555
Paracetamol, sulfathiazole and L-glutamic acid are presented as examples of pharmaceutical crystal polymorphic systems. The effect of N-acylated sulfathiazole derivatives (3-6) on sulfathiazole crystallisation is discussed, and possible modes of action presented. Methods for the control of the crystal polymorphism of L-glutamic acid which utilise the principles of conformation mimicry and co-operative binding are presented. The preparation of a series of bis-amides of EDTA derived from sulfathiazole, 5-aminoisophthalic acid and 4-hydroxyaniline (i.e. compounds 9a-c) is presented, as is data on the effect of these compounds on the crystallisation of, respectively, sulfathiazole, L-glutamic acid and paracetamol. 相似文献
5.
Mónica B. J. Moniz Phil M. Novis Paul A. Broady Michael D. Guiry 《Journal of phycology》2012,48(4):940-955
Trebouxiophytes of the genus Prasiola are well known in Antarctica, where they are among the most important primary producers. Although many aspects of their biology have been thoroughly investigated, the scarcity of molecular data has so far prevented an accurate assessment of their taxonomy and phylogenetic position. Using sequences of the chloroplast genes rbcL and psaB, we demonstrate the existence of three cryptic species that were previously confused under Prasiola crispa (Lightfoot) Kützing. Genuine P. crispa occurs in Antarctica; its presence was confirmed by comparison with the rbcL sequence of the type specimen (from the Isle of Skye, Scotland). Prasiola antarctica Kützing is resurrected as an independent species to designate algae with gross morphology identical to P. crispa but robustly placed in a separate lineage. The third species is represented by specimens identified as P. calophylla (Carmichael ex Greville) Kützing in previous studies, but clearly separated from European P. calophylla (type locality: Argyll, Scotland); this alga is described as P. glacialis sp. nov. The molecular data demonstrated the presence of P. crispa in Maritime and Continental Antarctica. P. antarctica was recorded from the Antarctic Peninsula and Shetland Islands, and P. glacialis from the Southern Ocean islands and coast. Such unexpected cryptic diversity highlights the need for a taxonomic reassessment of many published Antarctic records of P. crispa. The results also indicate that marine species of Prasiola form a well‐supported monophyletic group, whereas the phylogenetic diversity of freshwater species is higher than previously suspected (at least three separate lineages within the genus include species living in this type of environments). 相似文献
6.
7.
Bonnemaisonia hamifera Hariot (Rhodophyceae, Bonnemaisoniales) from Galway Bay, Ireland has been studied in the field and in laboratory culture.
The reproductive behaviour of tetrasporophytes and gametophytes in the field appeared to be strictly regulated by their temperature/daylength
responses as observed in culture. Tetrasporangia were abundant in early autumn when short days (<12 h of light per day) coincided
with seawater temperatures over about 11°C, the lower limit for sporangium formation. Spermatangia were observed in very young
gametophytes between mid-December and February, and in adult plants from late March until the end of May. They were absent
in mid-winter when low temperatures of about 2°C inhibited their formation. Carpogonia were first observed at the end of April
as seawater temperatures had by then risen to the required value of around 10°C. Carpogonia were fertilised and plants with
mature cystocarps were present until early July. The onset of reproduction was accompanied by a cessation of growth and led
to senescence within 2–3 months. Thus, gametophytes were absent in summer in spite of persistently favourable seawater temperatures.
In various parts of the North Atlantic Ocean, annual temperature regimes are such as to cause a certain lack of synchronisation
in the occurrence of reproductive male and female plants. This may account for the many anomalous reports of reproductive
plants in the wild.
Dedicated to Dr. Dr. h. c. P. Kornmann on the occasion of his eightieth birthday. 相似文献
8.
The morphology, reproduction and seasonal variation of a large foliose species of Cryptonemia collected in the drift in 1971–73 at Cork Harbour, Republic of Ireland, is described and compared with the known species of the genus. Although obviously closely related to a group of foliose Pacific species: C. borealis Kylin, C. obovata J. Ag. and C. angustata (Setch. et Gardn.) Dawson, the Irish Cryptonemia is not completely identifiable with any one of these and is therefore described as C. hibernica sp. nov., pending a revision of the genus. 相似文献
9.
The phenology and seasonal growth of Porphyra linearis Grev. were investigated in two morphologically dissimilar populations from the west coast of Ireland. Thallus size and reproductive status of individuals were monitored monthly between June 1997 and June 1998. Both populations exhibited a similar phenology: gametophyte stages appeared on the shore in October, with spermatangial and zygotosporangial sori appearing the following February; the gametophyte stage began to degenerate in April and had disappeared completely by June. However, significant differences in growth and reproduction in the field and in cultures of plants from the two populations were observed. Thallus length and width of individuals from one population were significantly longer throughout the sample period, and reproduction and sporulation occurred 1 month earlier. Also, in situ relative growth rates (RGRs) of plants differed significantly and were correlated with different climatic factors (sunshine, day length, irradiance, rainfall, seawater temperature, and intertidal temperatures), suggesting that plants were affected by two different microhabitats. At one site, blades were more exposed to wave action, sunshine, and extreme minimum temperatures, while at the other site, blades were more protected in winter, spring, and early summer. In culture, RGRs of blades from the second site were higher than RGRs of blades from the first site under short days, corroborating the field results and suggesting a degree of phenotypic differentiation between the two populations. However, there were no sequence divergences of the RUBISCO spacer between strains of the two P. linearis populations. 相似文献
10.
Mallikarjun S Beelagi SR Santosh Kumar Uma Bharathi Indrabalan Sharanagouda S Patil Ashwini Prasad KP Suresh Shiva Prasad Kollur Veeresh Santhebennur Jayappa Siddappa B Kakkalameli Chandrashekar Srinivasa Prabhakarareddy Anapalli Venkataravana Chandan Shivamallu 《Bioinformation》2021,17(4):479
Crimean-Congo hemorrhagic fever (CCHF) virus is one among the major zoonosis viral diseases that use the Hyalomma ticks as their transmission vector to cause viral infection to the human and mammalian community. The fatality of infectious is high across the world especially in Africa, Asia, Middle East, and Europe. This study regarding codon usage bias of S, M, and L segments of the CCHF virus pertaining to the host Homo sapiens, reveals in-depth information about the evolutionary characteristics of CCHFV. Relative Synonymous Codon Usage (RSCU), Effective number of codons (ENC) were calculated, to determine the codon usage pattern in each segment. Correlation analysis between Codon adaptation index (CAI), GRAVY (Hydrophobicity), AROMO (Aromaticity), and nucleotide composition revealed bias in the codon usage pattern. There was no strong codon bias found among any segments of the CCHF virus, indicating both the factors i.e., natural selection and mutational pressure shapes the codon usage bias. 相似文献