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731.
732.
Stephen R. Proulx Maria R. Servedio 《Evolution; international journal of organic evolution》2009,63(8):2031-2046
Population-specific preferences involved in premating isolation may be based on several different types of mating cues. Here, we compare the rates of spread of 12 different mating preferences that reflect preferences for local adaptation, male condition, and reinforcement. We introduce methods to dissect the components of the rate of spread to determine why certain mating preferences spread more quickly than others. We confirm the result that female preferences based on population-specific markers alone always spread faster than female preferences based only on a single local adaptation locus, regardless of the strength of natural selection on hybrid incompatibility. However, we find that this occurs for different reasons depending on the strength of selection against hybrids. Female preferences based on total male condition also achieved high rates of spread, suggesting that preferences for condition-dependent male displays may evolve under reinforcement scenarios. 相似文献
733.
734.
CHANDREYEE MITRA WILLIAM E. WAGNER ANTHONY J. ZERA AMANDA E. TOLLE 《Ecological Entomology》2011,36(2):152-160
1. Trade‐offs play a fundamental role in the evolution of many traits. 2. In wing‐polymorphic field crickets, the long‐winged morph can disperse from unfavourable environments, but has lower reproductive success than the short‐winged morph, because of costs associated with flight capability. 3. However, long‐winged individuals may minimise costs in favourable environments by histolysing their flight muscles and becoming flightless. 4. Few studies have examined how flight‐muscle histolysis affects male signalling and mate attraction. 5. We examined differences in singing activity and song characteristics among the flightless (short‐winged and histolysed long‐winged) and the flight‐capable male morphs, and female preferences for male song, in the sand field cricket. 6. We found: (i) both flightless morphs sang more than the flight‐capable morph, (ii) song characteristics varied among the three morphs, and (iii) females preferred songs characteristic of the long‐winged morphs. 7. Histolysis should increase mating success of long‐winged males because it increases singing activity. 8. Histolysed long‐winged males may have higher mating success than short‐winged males as they sing as frequently but produce more attractive songs. 9. Therefore, plasticity within the long‐winged morph may reduce costs of maturing in environments from which dispersal is not advantageous; non‐flying morphs may be pursuing different reproductive tactics. 相似文献
735.
T. S. Bellows Jr. 《Population Ecology》1985,27(1):55-64
The effects of host age on parasitoid reproductive capacity are studied using the pteromalid parasitoid Lariophagus distinguendusFörster and its bruchid hosts, Callosobruchus chinensis (L.) and C. maculatus (F.). A series of experiments were performed to investigate relationships between age and size of host parasitized and the developmental period of pre-imaginal progeny, sex ratio, female size, longevity, fecundity and oviposition rate. There was no effect of host size on preimaginal parasitoid developmental period. Sex ratio varied from less than 5% females from young (small) hosts to 60% females from mature (large) hosts. Adult size, female longevity, fecundity, and oviposition rate were also positively related to host age. Females provided mature hosts lived longer than those provided either young hosts or no hosts, possibly because of an increased ability to host-feed from the larger hosts. The implications of these findings to parasitoid population reproductive capacity and host-parasitoid synchrony are discussed. 相似文献
736.
A. Magdalena Hurtado Kim Hill Ines Hurtado Hillard Kaplan 《Human nature (Hawthorne, N.Y.)》1992,3(3):185-216
Even though female food acquisition is an area of considerable interest in hunter-gatherer research, the ecological determinants
of women’s economic decisions in these populations are still poorly understood. The literature on female foraging behavior
indicates that there is considerable variation within and across foraging societies in the amount of time that women spend
foraging and in the amount and types of food that they acquire. It is possible that this heterogeneity reflects variation
in the trade-offs between time spent in food acquisition and child care activities that women face in different groups of
hunter-gatherers. In this paper we discuss the fitness trade-offs between food acquisition and child care that Hiwi and Ache
women foragers might face. Multiple regression analyses show that in both populations the daily food acquisition of a woman’s
spouse is negatively related to female foraging effort. In addition, nursing mothers spend less time foraging and acquire
less food than do nonnursing women. As the number of dependents that a woman has increases, however, women also increase foraging
time and the amount of food they acquire. Some interesting exceptions to these general trends are as follows: (a) differences in foraging effort between nursing and nonnursing women are less pronounced when fruits and roots are in season
than in other seasons of the year; (b) foraging return rates decrease for Ache women as their numbers of dependents increase; and (c) among Ache women, the positive effect of number of dependents on foraging behavior is less pronounced when fruits are in
season than at other times of the year. Lastly, in the Hiwi sample we found that postreproductive women work considerably
harder than women of reproductive age in the root season but not in other seasons of the year. We discuss how ecological variation
in constraints, the number of health insults to children that Hiwi and Ache mothers can avoid, and the fitness benefits they
can gain from spending time in food acquisition and child care might account for differences and similarities in the foraging
behaviors of subgroups of Hiwi and Ache mothers across different seasons of the year. Valid tests of the explanations we propose
will require considerable effort to measure the relationship between maternal food acquisition, child care, and adverse health
outcomes in offspring.
This paper is dedicated to Nutsiya, the hardest-working grandmother we ever observed
Kristen Hawkes contributed useful information on female foraging among the Hadza. The research was funded by the National
Science Foundation (BNS-8613215, BNS-538228, BNS-8309834, BNS-8121209) and the L. S. B. Leakey Foundation. The senior author
was supported by fellowships from the Fundacion Gran Mariscal de Ayacucho of Venezuela and the National Institute of Health
(Grant No. 1 RO1 HD16221-01A2).
A. Magdalena Hurtado, Kim Hill, and Hillard Kaplan collaborate in research on the evolutionary ecology of the division of
labor by sex. Ines Hurtado is Senior Research Scientist at the Instituto Venezolano de Investigaciones Científicas, Venezuela.
She studies the immunology of parasite load and atopic illness in Hiwi foragers. 相似文献
737.
Lesley Nicole Braun 《Ethnos》2018,83(1):20-38
Women in Kinshasa, Democratic Republic of Congo are increasingly entering new professions partly due to an increase in higher education levels. In so doing, and as they become more visible in political and economic spheres, women are subjected to new forms of moral suspicion. While women have historically maintained a strong presence in the informal sector, such as commerce, new urban modes of employment dictate new kinds of visibility. It is within this context that notions of femininity and female virtue in Kinshasa continue to be redefined. This article explores several modes of employment for women, such as money-changing, journalism, and politics as they relate to local concepts of encadrement (supervision) and débrouillardisme (resourcefulness). Further, it also examines the threat that a woman's social network outside of her kin poses to men, as well as how women's participation in the economic sphere can motivate distrust between the genders. 相似文献
738.
Why do flowers of a hummingbird-pollinated mistletoe face down? 总被引:3,自引:1,他引:2
739.
740.
Darrell. J. Kemp 《Journal of Insect Behavior》2006,19(5):669-684
Ultraviolet (UV) colour patterns, particularly those deriving from surface structures, serve a role in sexual signalling and mate choice in a range of animal groups. In the butterfly Colias eurytheme (Pieridae), male-limited iridescent UV functions in species recognition, and has potential as an intraspecific sexual signal of mate quality. I compared the dorsal colouration and body size of males discovered ‘in-copula’ (N = 95) with a random sample of free-flying individuals (N = 129), both collected from a high density agricultural population located in Chandler, U.S.A. Despite reasonable variance in each trait, I found no among-group differences in UV characters (brightness, hue and angular visibility) or in the coincident pigmentary yellowish-orange (brightness and saturation). Statistical power was sufficient to detect all but the smallest among-group differences, and there was a marginally significant tendency for in-copula males to be larger. These data do not support the hypothesis for intraspecific female choice upon male dorsal colouration. However, I discuss how the density and apparently very young age of individuals in the sampling population may have pre-disposed this result, and thus, how sexual selection on male colouration may operate in a density dependent manner. 相似文献