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61.
62.
《Biological reviews of the Cambridge Philosophical Society》2018,93(2):811-826
Hierarchy theory recognises that ecological and evolutionary units occur in a nested and interconnected hierarchical system, with cascading effects occurring between hierarchical levels. Different biological disciplines have routinely come into conflict over the primacy of different forcing mechanisms behind evolutionary and ecological change. These disconnects arise partly from differences in perspective (with some researchers favouring ecological forcing mechanisms while others favour developmental/historical mechanisms), as well as differences in the temporal framework in which workers operate. In particular, long‐term palaeontological data often show that large‐scale (macro) patterns of evolution are predominantly dictated by shifts in the abiotic environment, while short‐term (micro) modern biological studies stress the importance of biotic interactions. We propose that thinking about ecological and evolutionary interactions in a hierarchical framework is a fruitful way to resolve these conflicts. Hierarchy theory suggests that changes occurring at lower hierarchical levels can have unexpected, complex effects at higher scales due to emergent interactions between simple systems. In this way, patterns occurring on short‐ and long‐term time scales are equally valid, as changes that are driven from lower levels will manifest in different forms at higher levels. We propose that the dual hierarchy framework fits well with our current understanding of evolutionary and ecological theory. Furthermore, we describe how this framework can be used to understand major extinction events better. Multi‐generational attritional loss of reproductive fitness (MALF) has recently been proposed as the primary mechanism behind extinction events, whereby extinction is explainable solely through processes that result in extirpation of populations through a shutdown of reproduction. While not necessarily explicit, the push to explain extinction through solely population‐level dynamics could be used to suggest that environmentally mediated patterns of extinction or slowed speciation across geological time are largely artefacts of poor preservation or a coarse temporal scale. We demonstrate how MALF fits into a hierarchical framework, showing that MALF can be a primary forcing mechanism at lower scales that still results in differential survivorship patterns at the species and clade level which vary depending upon the initial environmental forcing mechanism. Thus, even if MALF is the primary mechanism of extinction across all mass extinction events, the primary environmental cause of these events will still affect the system and result in differential responses. Therefore, patterns at both temporal scales are relevant. 相似文献
63.
C. Denys E. Stoetzel P. Andrews S. Bailon A. Rihane J. B. Huchet 《Historical Biology》2018,30(6):868-881
AbstractMost small terrestrial vertebrate accumulations in archaeological and palaeontological sites result from predation but we are far from having an exhaustive knowledge of modern predators’ diet, ecological niches and bone modification patterns especially in North African sites. The few neotaphonomic referentials available result from taxon-specialized palaeontologists’ initiatives. A survey of the literature on North Africa predators shows that their prey diversity is high and not only include rodent and shrews but also amphibians, squamates, bats and insects. We performed here a pilot taphonomic study of a Moroccan Tyto alba nest pellets including the whole taxa consumed (birds, rodents, shrews, amphibians, insects). We analyzed bone representation, fragmentation and digestion for each taxa and then compared the results. We observe differences between the taxa but on the whole find higher modification levels for this assemblage compared to roost sites of barn owls from other sites. We used for the comparisons homologous bones like the femur and the humerus and also found differences between the taxa. For example, digestion was lower on amphibians and birds than on micromammals. We discuss here some methodological issues as well as archaeological and palaeoenviromental ones by comparison with the Pleisto-Holocene site of El Harhoura II (Morocco). 相似文献
64.
Martha R. Weiss 《Ecology letters》2003,6(4):361-370
Although both feeding and elimination of waste are imperatives for all animals, ecologists and evolutionary biologists have devoted considerable attention to foraging, while largely ignoring defecation. Many organisms, however, exhibit defecation behaviours that appear to have been shaped by natural selection in a range of ecological contexts. Accumulation of waste may pose particular challenges for animals that exhibit high site fidelity or live within enclosed spaces. In a taxonomically widespread but largely unexamined behaviour, many caterpillars that construct and inhabit leaf shelters ballistically eject their individual faecal pellets (frass) great distances at great speeds. Here, I show that elimination of chemical cues for natural enemies is likely to have been a driving force behind the evolution of frass ejection behaviour in skipper caterpillars; hygiene and crowding are less important in this system. 相似文献
65.
Absolute hearing thresholds and critical masking ratios in the European barn owl: a comparison with other owls 总被引:1,自引:0,他引:1
M. L. Dyson G. M. Klump B. Gauger 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,182(5):695-702
Absolute thresholds and critical masking ratios were determined behaviorally for the European barn owl (Tyto alba guttata). It shows an excellent sensitivity throughout its hearing range with a minimum threshold of −14.2 dB sound pressure level
at 6.3 kHz, which is similar to the sensitivity found in the American barn owl (Tyto alba pratincola) and some other owls. Both the European and the American barn owl have a high upper-frequency limit of hearing exceeding
that in other bird species. Critical masking ratios, that can provide an estimate for the frequency selectivity in the barn
owl's hearing system, were determined with a noise of about 0 dB spectrum level. They increased from 19.1 dB at 2 kHz to 29.2 dB
at 8 kHz at a rate of 5.1 dB per octave. The corresponding critical ratio bandwidths were 81, 218, 562 and 831 Hz for test-tone
frequencies of 2, 4, 6.3 and 8 kHz, respectively. These values indicate, contrary to expectations based on the spatial representation
of frequencies on the basilar papilla, increasing bandwidths of auditory filters in the region of the barn owl's auditory
fovea. This increase, however, correlates with the increase in the bandwidths of tuning curves in the barn owl's auditory
fovea.
Accepted: 27 November 1997 相似文献
66.
67.
68.
Frederick A. Dadzie Angela T. Moles Todd E. Erickson Nathali Machado de Lima Miriam Muñoz-Rojas 《Restoration Ecology》2024,32(2):e14025
Restoration managers inoculate microorganisms to enhance soil function and improve restoration success, but the efficacy of these inoculations in real-world conditions is still unclear. We conducted a field experiment to test whether applying extruded seed pellets inoculated with native microbes affected soil properties related to ecosystem function in severely degraded mine soil. We found that inoculating with bacteria did not affect soil carbon, metabolic quotient (a measure of microbial stress), or basal respiration, but increased soil nitrogen by 75%, substrate-induced respiration by 147% and reduced carbon-to-nitrogen ratio by 44% compared to the control. This suggests that the bacteria inoculant contained free-living N fixers that increased the soil N content. Thus, inoculating with bacteria could supplement nitrogen fertilizers in degraded soils during soil restoration. However, we found that inoculating with a mix of bacteria and cyanobacteria did not affect any of the soil properties. This finding is counter to results in laboratory studies, suggesting that field tests are critical for understanding real-world outcomes of microbial inoculation. Finally, we found that soil microbial composition was changed by the inoculation with a mix of bacteria and cyanobacteria. None of the treatments significantly changed the diversity of soil microbial communities. Our data suggest that microbial inoculation could improve some aspects of ecosystem function and thus provide beneficial effects that might facilitate restoration of degraded sites. 相似文献
69.
Steven E. Churchill 《American journal of physical anthropology》1996,100(4):559-583
Evolutionary biologists are largely polarized in their approaches to integrating microevolutionary and macroevolutionary processes. Neo-Darwinians typically seek to identify population-level selective and genetic processes that culminate in macroevolutionary events. Epigeneticists and structuralists, on the other hand, emphasize developmental constraints on the action of natural selection, and highlight the role of epigenetic shifts in producing evolutionary change in morphology. Accordingly, the ways in which these paradigms view and address morphological contrasts between classes of related organisms differ. These paradigms, although seldomly explicitly stated, emerge in paleoanthropology as well. Considerations of postcranial morphological contrasts between archaic and modern humans typically fall into one of two broad interpretive models. The first derives from the neo-Darwinian perspective and holds that evolution in the postcranial skeleton was largely mosaic (operating in a particulate manner), and that temporal change in specific traits informs us about behavioral shifts or genetic evolution affecting isolated anatomical regions (i.e., adaptive behavioral inferences can be made from comparative studies of individual trait complexes). The alternative model follows from the epigeneticist paradigm and sees change in specific postcranial traits as correlated responses to change in overall body form (involving shifts in regulation of skeletal growth, or selective and developmental responses to broad adaptive shifts). By this view, integration of functional systems both constrains and directs evolution of various traits, and morphological contrasts inform us about overall change in body form related to change in such things as overall growth patterns, climatic adaptation, and technological dependency. These models were tested by confirmatory factor analysis using measures of upper body form and upper limb morphological traits in Eurasian Neandertal and early modern fossils and recent human samples. Results indicate (1) a model of morphological integration fits the data better than a model of no integration, but (2) this integration accounts for less than half of the variance in upper limb traits, suggesting a high degree of tolerance for particulate evolution in the context of an integrated upper body plan. Significant relationships were detected between joint shapes and body size, between humeral shaft shape and body size and chest shape, and between measures of biomechanical efficiency and robusticity. The observed morphological differences between late archaic and early modern humans reflect particulate evolution in the context of constraints imposed by genetic and morphological integration. While particulate approaches to interpreting the fossil record appear to be justified, attention must also be paid to delineating the nature and extent of morphological integration and its role in both constraining and producing observed patterns of variation between groups. Confirmatory factor analysis provides a means of examining trait covariance matrices, and serves as a useful method of identifying patterns of integration in morphology. © 1996 Wiley-Liss, Inc. 相似文献
70.
Miyada Zamoum Nasserdine Sabaou Florence Mathieu Abdelghani Zitouni 《Biocontrol Science and Technology》2017,27(6):723-738
Rhizoctonia solani is one of the most problematic soil-borne pathogenic fungi for several crop cultures worldwide. This study highlights the effectiveness of high-antagonistic Streptomyces rochei strain PTL2, isolated from root tissues of Panicum turgidum, in controlling the R. solani damping-off and growth promotion of tomato (cv. Marmande) seedlings. The isolate PTL2 was characterised for in vitro biocontrol and plant growth-promoting traits. It exhibited remarkable positive results in all trials, including production of hydrogen cyanide, siderophores, 1-aminocyclopropane-1-carboxylate deaminase and phytohormones, chitinolytic activity and inorganic phosphate solubilisation. PTL2 spores were formulated as wettable talcum powder, sodium alginate pellets and sodium alginate-clay pellets. Their abilities in the biocontrol of R. solani and plant growth promotion were investigated in autoclaved and non-autoclaved soils. Talcum powder and sodium alginate pellets significantly reduced the damping-off severity index compared to a positive control. The talcum powder exhibited the highest protective activity, reducing the disease incidence from 89.3% to 14.1%, whereas chemical seed treatment with Thiram® provided a disease incidence of 16.7%. Furthermore, the talc-based powder formulation resulted in greatest increases in the root length, shoot length and dry weight of seedlings. The interesting biocontrol potential and growth enhancement of tomato seedlings open up promising perspectives for the possible application of talcum powder formulation based on PTL2 spores in crop improvement. 相似文献