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41.
Galeommatid bivalves from Phuket, Thailand 总被引:1,自引:0,他引:1
42.
SYNOPSIS. Protostomes and deuterostomes can be characterizedby two completely separate sets of characters. Protostome charactersare downstream- collecting ciliary bands with compound ciliaon multiciliate cells and central nervous system with apicalbrain and ventral paired or fused cords; spiral cleavage isonly found in the protostome group Spiralia. Deuterostome charactersare upstream-collecting ciliary systems with separate ciliaon monociliate cells, dorsal central nervous system and lossof the larval apical organ in the adults, and archimery withprosome, mesosome and metasome. Only the ectoproct bryozoanslack all the justmentioned characters; they are referred tothe protostomes on basis of their metamorphosis which resemblesthat of entoprocts. The two bilateral groups have probably evolvedindependently from a radial, gastraea-like ancestor 相似文献
43.
MOLLUSCAN SHELL PIGMENTS: AN IN SITU RESONANCE RAMAN STUDY 总被引:2,自引:0,他引:2
HEDEGAARD CLAUS; BARDEAU JEAN-FRANCOIS; CHATEIGNER DANIEL 《Journal of Molluscan Studies》2006,72(2):157-162
Using Resonance Raman microspectrometry we identify polyenesas shell pigments in 13 gastropod, 1 cephalopod and 4 bivalvetaxa. The pigments are either isolated polyenes or polyenesbound to other molecules. Polyenes are present in coloured partsof the shell of all investigated taxa. Pigments differ betweentaxa and there is no trivial relationship between colour, pigmentand taxon. The same colour in different taxa may be due to differentpigments; different colours in the same taxon are due to differentpigments; different colour saturation is due to different concentrationof the same pigment. The pigment polyenes are unsubstitutedchains of 813 conjugated double-bonds (1626 carbonatoms) in the chain, with terminals incorporating CH3groups. This is the first demonstration of polyenes as shellpigment in the Mollusca. We also identify a carotenoid as theexternal, yellow pigment in Cypraea moneta. (Received 2 December 2004; accepted 18 August 2005) 相似文献
44.
SHELL STRUCTURES OF THE RECENT VETIGASTROPODA 总被引:4,自引:0,他引:4
A cladistic analysis of the shell microstructures of RecentVetigastropoda demonstrates, it is more parsimonious to assumecrossed lamellar shell structures, rather than nacreous, areplesiomorphic. The clade Vetigastropoda is characterized byhaving intersected crossed platy shell structure. The analysissuggests resolution of the internal phylogeny of the Vetigastropoda,particularly separation of a crown group with nacreous shells,composed of Haliotidae, Pleurotomariidae, Seguenziidae, Stomatellidae,Trochidae, and Turbinidae, separated from an unresolved gradewith cross lamellar structures, Fissurellidae, Osteopeltidae,and Pseudococculin-idae. It is also suggested, that Phasianellidaeis neither part of nor sister taxon to Turbinidae. 相似文献
45.
Morphological Approaches to Phylogeny 总被引:1,自引:0,他引:1
SYNOPSIS. Traditional views on the interrelationships of themajor animal groups are based on morphological characters, butmolecular data of various types have in the last decade givenindications of new and sometimes quite puzzling phylogenies.This should be an incentive not only to reevaluation of theavailable morphological characters but also to new studies tofill the voids in our knowledge. Modern morphology is not concernedonly with traditional studies of structure and ontogeny of organsystems, but also with newer methods, such as SEM, TEM, immunocytochemistry,and cell marking. This has given morphology new dimensions,but it also has shown that vast areas of the animal kingdomremain very poorly known even through traditional studies. Phylogenetictrees built on morphology (and molecular trees with morphologicalcharacters added) demonstrate morphological characters thatare in conflict with the phylogeny, and therefore should bereinvestigated; they also indicate areas where new researchcan contribute significantly to our understanding of the pathwaysof the evolution. Morphological phylogeny has the distinct advantagethat characters of ancestors can be inferred and the evolutionarychanges checked in terms of functional continuity and hypothesesof adaptation. 相似文献
46.
A. K. GITHEKO A. D. BRANDLING-BENNETT M. BEIER C. M. MBOGO F. K. ATIELI M. L. OWAGA F. JUMA F. H. COLLINS 《Medical and veterinary entomology》1993,7(4):373-376
Abstract. In preparation for field studies of transmission-blocking malaria vaccines, a study was carried out to determine whether P. falciparum infections obtained in An. gambiae blood-fed at 16.00 hours were quantitatively similar to infections obtained at 23.00 hours. Using a group of children aged 5-12 years from villages at Ahero, near Kisumu in Kenya, 71/74 (96%) of whom were found to be positive for P. falciparum parasitaemia, one batch of fifty colony-bred An. gambiae females were fed on volunteers at 16.00 hours and another batch at 23.00 hours. No statistically significant differences were found in the proportions of mosquitoes becoming infected, the numbers of children infecting mosquitoes or the mean numbers of malaria oocysts developing in mosquitoes blood-fed at the different times. Because mosquito infections obtained by day (16.00 hours) are equivalent in quantity to those obtained at night (23.00 hours), experimental infections can be carried out in the afternoon, when it is most convenient, rather than during the night. 相似文献
47.
DETECTION OF A PUTATIVE VIRULENCE cadF GENE OF CAMPYLOBACTER JEJUNI OBTAINED FROM DIFFERENT SOURCES USING A MICROFABRICATED PCR CHIP 总被引:1,自引:0,他引:1
48.
GEORGIOS KROUMPOUZOS JÜRGEN EBERLE CLAUS GARBE CONSTANTIN E. ORFANOS 《Pigment cell & melanoma research》1994,7(5):348-353
In this study, we examined the expression of c-fos, c-myc, mutant c-Ha-ras and mutant p53 proteins in three normal human melanocyte cell lines and the following 12 melanoma cell lines: M5, Mewo, A375, Bro, Mel 2a, O-Mel II, IgR 39, SkMel-13, -19, -28 Mel-57 and NKI-4, using an immunohistochemical assay (APAAP). An effort was made to correlate oncogene expression with growth parameters, differentiation antigens (HMB-45, vla-2, k.1.2.58, HLA-DR, HLA-I), and pigmentation. All melanocyte cell lines were negative for the oncogenes examined, whereas six of the melanoma cell lines were found also positive (three for c-fos, two for c-myc, one for c-Ha-ras, and four for p53). Three melanoma cell lines expressed one oncogene and three the combination c-fos/p53. These three melanoma cell lines were positive for the “late” tumor progression marker A. 1. 43 (vla-2 adhesion molecule) and negative for the differentiation marker k. 1. 2. 58. Positivity for A. 1. 43 combined with negative staining for k. 1. 2. 58 was found in six out of the 12 cell lines. The observed oncogene expression correlated neither with growth parameters nor melanin content. The present findings revealed a coexpression of mutant p53 and c-fos proteins being associated with a highly malignant phenotype in melanoma cell lines. Further studies are necessary to clarify the significance of the above findings 相似文献
49.
CLAUS NIELSEN 《Zoologica scripta》1996,25(1):61-75
Three new species of Loxosoma are described, L. nung and L. song , on the polychaete Pectinaria brevispinis from the reef flat in front of Phuket Marine Biological Center, and L. sum on the polychaete Axiothella obockiensis from a sand flat at Nai Yang Beach, Phuket Island. The genus Loxosoma is briefly reviewed. Species originally referred to Loxosoma but now transferred to Loxosomella are listed; insufficiently characterized species probably belonging to Loxosomella are listed as well. The monospecific genus Loxostemma is synonymized with Loxosoma . The subgenus name Loxosomina is proposed to replace the junior homonym Loxomorpha . 相似文献
50.
ABSTRACT We examined effects of prescribed fire on 3 wintering, bark-foraging birds, hairy woodpeckers (Picoides villosus), pygmy nuthatches (Sitta pygmaea), and white-breasted nuthatches (S. carolinensis), in ponderosa pine (Pinus ponderosa) forests of northern Arizona, USA. During winters of 2004–2006, we compared bird density, foraging behavior, and bark beetle activity among burned treatment and unburned control units. Hairy woodpecker density was 5 times greater in burn units, whereas white-breasted nuthatches and pygmy nuthatches had similar densities between treatments. Compared to available trees, trees used by foraging hairy woodpeckers had 9 times greater odds of having bark beetles in control units and 12 times greater odds in burn units. Tree diameter appeared to be the main factor bark-foraging birds used in selecting winter foraging trees. Our results suggest that forest managers can use prescribed fire treatments without detrimental effects to wintering nuthatches, while providing additional food to hairy woodpeckers. 相似文献