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101.
CRAIG J. TAMBLING ELISSA Z. CAMERON JOHAN T. DU TOIT WAYNE M. GETZ 《The Journal of wildlife management》2010,74(3):549-556
ABSTRACT Knowledge of the range, behavior, and feeding habits of large carnivores is fundamental to their successful conservation. Traditionally, the best method to obtain feeding data is through continuous observation, which is not always feasible. Reliable automated methods are needed to obtain sample sizes sufficient for statistical inference. Identification of large carnivore kill sites using Global Positioning System (GPS) data is gaining popularity. We assessed performance of generalized linear regression models (GLM) versus classification trees (CT) in a multipredator, multiprey African savanna ecosystem. We applied GLMs and CTs to various combinations of distance-traveled data, cluster durations, and environmental factors to predict occurrence of 234 female African lion (Panthera leo) kill sites from 1,477 investigated GPS clusters. Ratio of distance moved 24 hours before versus 24 hours after a cluster was the most important predictor variable in both GLM and CT analysis. In all cases, GLMs outperformed our cost-complexity-pruned CTs in their discriminative ability to separate kill from nonkill sites. Generalized linear models provided a good framework for kill-site identification that incorporates a hierarchal ordering of cluster investigation and measures to assess trade-offs between classification accuracy and time constraints. Implementation of GLMs within an adaptive sampling framework can considerably increase efficiency of locating kill sites, providing a cost-effective method for increasing sample sizes of kill data. 相似文献
102.
Thirty axenically grown reference strains belonging to 15 different Acanthamoeba spp. were investigated for isoenzyme patterns by agarose isoelectric focusing in the pH range 3–10. Zymograms of acid phosphatase, leucine amino peptidase, malate dehydrogenase, propionyl esterase, glucose phosphate isomerase, phosphoglucomutase, and alcohol dehydrogenase were compared. The same strains were also analyzed for protein patterns separated by agarose isoelectric focusing in a pH gradient of 5–8. The results suggested changes in taxonomy within morphology group II of Pussard & Pons. Acanthamoeba paradivionensis becomes a synonym of A. divionensis. Although this species seems to be related to A. rhysodes, it could not be concluded that the species names are synonyms since the type strain of A. rhysodes was not available for comparison. In the subgroup A. polyphaga–A. quina–A. lugdunensis, A. lugdunensis becomes the species name for pathogenic strains of this subroup, A. quina for the nonpathogenic strains, while A. polyphaga is the species name for an atypical strain. Two strains of A. castellanii showed different zymograms from strain Neff of this species, but related protein patterns. In group III, A. pustulosa is found to be a synonym of A. palestinensis, while one strain of A. lenticulata is also found to belong to the A. palestinensis species. All other species names in both morphology groups could be retained as valuable, on the basis of the techniques used. Group I was not investigated, as axenic cultures could not be obtained. 相似文献
103.
Holobomolochus confusus is reported for the first time from the western Atlantic coasts. The external morphology, especially that of the male, of specimens from the nasal cavities of cod, Gadus morhua , from the west coast of Sweden is described and discussed. Sexual dimorphism occurs in the maxillipeds, abdomen, first antenna and in the armature of the legs. The results indicate that the species has a good swimming ability and that this may allow the male especially to change hosts. 相似文献
104.
Evidence for the Ancestral Origin of Group I Introns in the SSUrDNA of Naegleria spp. 总被引:1,自引:0,他引:1
JOHAN F. DE JONCKHEERE 《The Journal of eukaryotic microbiology》1994,41(5):457-463
ABSTRACT The sequence variation within the group I intron in five Naegleria spp. was studied and compared with the sequence variation within the flanking small subunit ribosomal DNA. Considerable sequence divergence was observed in the introns as well as in the rDNA. In the intron deletions and insertions are only detected in the sequence contributing to the secondary structure, not in the open reading frame. Most of the sequence variation is detected in the unpaired loops. In the case of nucleotide substitution in helices, compensating base pair changes were observed. The sequence variation does not induce variation in the secondary structure model. The phylogenetic tree based on the intron sequences is similar to the tree based on the flanking rDNA sequences. This observation indicates that the intron might have been acquired at an early stage in evolution, and lost in the majority of Naegleria spp. 相似文献
105.
The Dufour gland epithelium in Aenictus has a crenellate appearance, a condition previously found only in the primarily African genus Dorylus . This character, taken alone, strongly suggests that these two genera share a common ancestry, as is presently reflected in their placement in the subfamily Dorylinae, and that an independent, convergent origin for them, as has been proposed in the triphyletic hypothesis for army ant evolution, is incorrect. 相似文献
106.
JOHAN FREDRIK BOCKELIE CHRISTOPHER R. C. PAUL 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1983,16(4):257-264
The European Ordovician edrioasteroid Cyathotheca has a variable tubular theca composed of a single plate. The oral surface is covered by five large inter-radial deltoids fused to biserial ambulaeral cover plates, and a periproct in the C-D inter-radius accompanied by two or three adanal plates. Cyathotheca lacks ambulaeral flooring plates. The American and Baltic Ordovician genus Cyathocystis is identical except that it has a complete ring of small peripheral plates surrounding the deltoids. Both genera are assigned to the family Cyathocystidae. The Devonian genera Timeischytes and Hadrochthus are regarded as neotenous offshoots from the Agelacrinitidae and unrelated to cyathocystids. True cyathocystids arose neotenously from the Cambrian stromatocystitids by attachment of the centro-dorsal and failure to develop further aboral or ambulaeral plates. This branch represents a separate evolutionary line to the main stromatocystitid-edrioasterid-isorophid line. 相似文献
107.
108.
SMALL CHRIS; BOTHA FREDERIK C.; PRETORIUS JOHAN C.; HOFFMAN ERIKA 《Journal of experimental botany》1991,42(2):277-280
In addition to CO2, low concentrations, in decreasing orderof effectiveness, of Ag, Ni, Hg, Zn, Co, Pb, and Cu salts tendedto reduce soaking injury in bean seeds. Their effects did notappear to be due to ethylene antagonism. The CO2 effect wasnot related to it lowering the pH of the soaking solution. Soakinginjury was aggravated by L-a-(2-aminoethoxyvinyl) glycinehydrochloride(AVG) and 2,5-norbornadiene (NBD) and this effect was reversedby ethrel. Soaking in the presence of an ethylene absorbantHg(CIO4)2 increased injury. The beneficial effect of CO2 wasdiminished by NBD and this was reversed by ethrel. Ethrel andethylene tended to decrease soaking injury. Injurious treatmentsresulted in less ethylene release by soaked seeds than beneficialtreatments. It is concluded that ethylene does not cause soakinginjury but appears to be partially required for its prevention. Key words: Phaseolus vulgaris, soaking injury, ethylene, ethylene antagonists, heavy metals 相似文献
109.
On the similarity of the Dufour gland secretion and the cuticular hydrocarbons of some bumblebees 总被引:4,自引:0,他引:4
Abstract. There is a close correspondence in composition between the hydrocarbons of the Dufour gland and the cuticular hydrocarbons of workers of some bumblebee species. This correspondence is characteristic of the species, and independent of the place and time of collection. 相似文献
110.