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521.
M. M. Webster J. Goldsmith A. J. W. Ward P. J. B. Hart 《Behavioral ecology and sociobiology》2007,62(2):273-280
The structure of social animal groups can be dynamic, characterized by high rates of group fission and fusion. Despite this,
group composition is often well ordered by factors such as species, body size and by numerous other phenotypic traits. Research
in shoaling fishes has revealed that individuals refine group membership decisions still further and are capable of assimilating
chemical cues pertaining to recent habitat and prey use by prospective group mates, preferring to associate with others whose
recent resource use history closely matches their own. In this study, we firstly examined the dynamics of the formation and
breakdown of these preferences, revealing that they can be acquired and replaced in a matter of just a few hours. Using such
cues enables individuals to accurately assess the resource use of conspecifics, allowing them to indirectly sample the local
environment while reducing the chances of acquiring outdated information that can precipitate maladaptive behaviors. Secondly,
we found that shoals composed of individuals with shared recent habitat use history were more cohesive compared to those where
the constituent individuals differed in recent habitat use. Increased shoal cohesion may reduce predation risk, and could
enhance the ability of individuals to detect and use social information. 相似文献
522.
J. Antonio Baeza 《Behavioral ecology and sociobiology》2007,61(3):365-370
Sex allocation theory predicts phenotypic adjustments by individuals in their investments into the male and female reproductive function in response to environmental conditions. I tested for phenotypically plastic shifts in sex allocation in a protandric simultaneous hermaphrodite, in which individuals mature and reproduce as males first, and later in life, as simultaneous hermaphrodites. I predicted that initially maturing males should adjust the timing of maturation as hermaphrodites according to male mating opportunities mediated by population size of hermaphrodites. In a first experiment, males maintained with only one hermaphrodite reduced the time they spent as males in comparison to males maintained with no conspecifics, presumably because total reproductive output is maximized by two individuals being simultaneous hermaphrodites when the mating system is a pair. Conversely, males maintained in groups with two or more hermaphrodites increased the time they spent as males in comparison to single males. This delay in maturation was not an effect of resource depletion with increasing shrimp density because the growth rate of males did not differ among most of the experimental treatments. One hypothesis to explain this social mediation of sex allocation is that the smaller males are more successful in mating as males than are the larger hermaphrodites: it will pay reproductively for males to delay maturation as hermaphrodites in large but not in small groups. In agreement with this notion, a second experiment demonstrated that smaller males were four times more successful than were larger hermaphrodites in inseminating shrimps reproducing as females. The informative cue that males may use to perceive different group sizes deserves further attention. 相似文献
523.
Joan B. Silk Jeanne Altmann Susan C. Alberts 《Behavioral ecology and sociobiology》2006,61(2):183-195
Sociality has positive effects on female fitness in many mammalian species. Among female baboons, those who are most socially integrated reproduce most successfully. Here we test a number of predictions derived from kin selection theory about the strength of social bonds among adult female baboons. Our analyses are based on systematic observations of grooming and association patterns among 118 females living in seven different social groups in the Amboseli Basin of Kenya over a 16-year period. Females in these groups formed the strongest bonds with close kin, including their mothers, daughters, and maternal and paternal sisters. Females were also strongly attracted toward females who were close to their own age, perhaps because peers were often paternal sisters. Females’ bonds with their maternal sisters were strengthened after their mother’s deaths, whereas their relationships with their maternal aunts were weakened after their mother’s death. In addition, females formed stronger bonds with their paternal sisters when no close maternal kin were available, and they compensated for the absence of any close kin by forming strong bonds with nonrelatives. Taken together, these data suggest that social bonds play a vital role in females’ lives, and the ability to establish and maintain strong social bonds may have important fitness consequences for females.Joan B. Silk is on sabbatical at Cambridge University from September 2005 to August 2006. Tel.: +44-7929759697; Fax: +44-1223-335460. 相似文献
524.
Varenka Lorenzi Ryan L. Earley Matthew S. Grober 《Behavioral ecology and sociobiology》2006,59(6):715-722
Sex change in marine teleost fishes is commonly regulated by social factors. In species that exhibit protogynous sex change,
such as the bluebanded goby Lythrypnus dalli, the most dominant female typically initiates sex change when a male is removed from the social group. Females can use visual,
chemical or tactile cues to assess the presence or absence of a male. The primary goal of our study was to determine whether
the olfactory and visual presence of a male versus its behavioural interactions with females were important for mediating
sex change. We exposed females to three different treatments: absence of a male, presence of a male that could physically
interact with her and presence of a male behind a barrier that allowed visual and olfactory interactions but prohibited physical
interactions. Sex change occurred in the absence of a male but not in the presence of a male that could physically interact
with the female. The presence of a male behind the barrier did not prevent sex change but affected the timing of sex change.
Season appeared to affect the latency to initiate male typical courtship, with a delay at the end of the reproductive season
only when the male was present behind the barrier. We discuss the seasonal results in terms of L. dalli life history and the potential benefits and costs of changing sex late in the season in the presence or absence of aggressive
reinforcement by the male. Our results identify direct behavioural interactions as an important proximate mechanism in the
social regulation of sex change in L. dalli. 相似文献
525.
Vincent Dietemann Jochen Pflugfelder Stephan Härtel Peter Neumann Robin M. Crewe 《Behavioral ecology and sociobiology》2006,60(6):785-793
Social parasites exploit their host’s communication system to usurp resources and reproduce. In the honeybee, Apis mellifera, worker reproduction is regulated by pheromones produced by the queen and the brood. Workers usually reproduce when the queen is removed and young brood is absent. However, Cape honeybee workers, Apis mellifera capensis, are facultative intraspecific social parasites and can take over reproduction from the host queen. Investigating the manner in which parasitic workers compete with host queens pheromonally can help us to understand how such parasitism can evolve and how reproductive division of labour is regulated. In A. m. capensis, worker reproduction is associated with the production of queen-like pheromones. Using pheromonal contest experiments, we show that Apis mellifera scutellata queens do not prevent the production of queen-like mandibular gland compounds by the parasites. Given the importance of these pheromones in acquiring reproductive status, our data suggest that the single invasive lineage of parasitic workers occurring in the range of A. m. scutellata was selected for its superior ability to produce these signals despite the presence of a queen. Such resistance was indeed less frequent amongst other potentially parasitic lineages. Resistance to reproductive regulation by host queens is probably the key factor that facilitates the evolution of social parasitism by A. m. capensis workers. It constitutes a mechanism that allows workers to evade reproductive division of labour and to follow an alternative reproductive option by acquiring direct fitness in foreign colonies instead of inclusive fitness in their natal nests. 相似文献
526.
Multiple mating by social insect queens is a common phenomenon despite likely imposing substantial costs on queens. Mating with several males could be adaptive if a more genetically diverse worker force is better able to always handle any task sufficiently well, leading to a higher colony homeostasis. If multiple-paternity colonies are more homeostatic, then I propose that they may constitute less stressful rearing environments for developing sexuals. The effective stress levels experienced by developing males and queens may, however, also depend on colony productivity and sex-ratio preferences. I tested these hypotheses in the ant Lasius niger by examining whether the fluctuating asymmetry, means and coefficients of variation of a set of phenotypic traits in males and new queens co-varied with the effective number of patrilines per colony, colony productivity or sex ratio.Little support was found that the level of intra-colonial genetic diversity affects the variation of phenotype in sexuals. In 1 out of 2 years, however, females from colonies with high effective patriline numbers were heavier relative to their head width than were females from colonies with few patrilines. Support was found for the hypothesis that colonies with more resources may invest more in individual sexuals, and tendencies suggested that sexuals may receive better treatment when they belong to the majority sex of their colony.Communicated by J. Heinze 相似文献
527.
The bottlenose dolphin community of Doubtful Sound features a large proportion of long-lasting associations 总被引:4,自引:0,他引:4
David?LusseauEmail author Karsten?Schneider Oliver?J.?Boisseau Patti?Haase Elisabeth?Slooten Steve?M.?Dawson 《Behavioral ecology and sociobiology》2003,54(4):396-405
More than 12 studies of different bottlenose dolphin populations, spanning from tropical to cold temperate waters, have shown that the species typically lives in societies in which relationships among individuals are predominantly fluid. In all cases dolphins lived in small groups characterised by fluid and dynamic interactions and some degree of dispersal from the natal group by both sexes. We describe a small, closed population of bottlenose dolphins living at the southern extreme of the species' range. Individuals live in large, mixed-sex groups in which no permanent emigration/immigration has been observed over the past 7 years. All members within the community are relatively closely associated (average half-weight index>0.4). Both male–male and female–female networks of preferred associates are present, as are long-lasting associations across sexes. The community structure is temporally stable, compared to other bottlenose dolphin populations, and constant companionship seems to be prevalent in the temporal association pattern. Such high degrees of stability are unprecedented in studies of bottlenose dolphins and may be related to the ecological constraints of Doubtful Sound. Fjords are low-productivity systems in which survival may easily require a greater level of co-operation, and hence group stability. These conditions are also present in other cetacean populations forming stable groups. We therefore hypothesise that ecological constraints are important factors shaping social interactions within cetacean societies.Communicated by D. Watts 相似文献
528.
Scott?NunesEmail author Eva-Maria?Muecke Zaira?Sanchez Rebekah?R.?Hoffmeier Lesley?T.?Lancaster 《Behavioral ecology and sociobiology》2004,56(2):97-105
We evaluated the relationship between play behavior and motor development in juvenile Beldings ground squirrels (Spermophilus beldingi). We observed the social play behavior of juvenile S. beldingi during their primary play period and conducted motor skills tests at the beginning and end of the play period. We also placed different-sized boxes in juveniles natal areas during the play period and observed box climbing behavior to assess the difficulty of non-social play tasks undertaken by juveniles. Rates of social play were greater in heavy compared to light individuals, supporting the idea that juveniles must selectively allocate available energy among competing demands such as growth and play behavior. Juveniles played almost exclusively with littermates; however, they did not play at equal rates with all partners. Rather, they tended to have one preferred partner and to devote significantly less time to playing with each additional partner, indicating that stability and familiarity are important in social play interactions. Motor skill levels at the end of the play period were greater among juveniles who played with many compared to few partners, suggesting that exposure to a variety of play interactions helps facilitate motor development. Improvement in motor skills was greater among juveniles who played at high compared to low rates, had several compared to few male play partners, and engaged in several compared to few play bouts with male partners, suggesting that elements of play with male partners prominently influence motor development. The partner with whom males played at the highest rate tended to be male, and rates of social play were highest in male biased litters, raising the possibility that improvement in motor proficiency arising from play with males may be especially important for young males. The size of experimental boxes that juveniles climbed increased during the play period, supporting the idea that individuals choose play tasks that pose the greatest challenge.Communicated by T. Czeschlik 相似文献
529.
Ludivine de Menten Denis Fournier Colin Brent Luc Passera Edward L. Vargo Serge Aron 《Behavioral ecology and sociobiology》2005,58(6):527-533
Social Hymenoptera are general models for the study of parent-offspring conflict over sex ratio, because queens and workers frequently have different reproductive optima. The ant Pheidole pallidula shows a split distribution of sex ratios with most of the colonies producing reproductives of a single sex. Sex ratio specialization is tightly associated with the breeding system, with single-queen (monogynous) colonies producing male-biased brood and multiple-queen (polygynous) colonies female-biased brood. Here, we show that this sex specialization is primarily determined by the queens influence over colony sex ratio. Queens from monogynous colonies produce a significantly more male-biased primary sex ratio than queens from polygynous colonies. Moreover, queens from monogynous colonies produce a significantly lower proportion of diploid eggs that develop into queens and this is associated with lower rate of juvenile hormone (JH) production compared to queens from polygynous colonies. These results indicate that queens regulate colony sex ratio in two complementary ways: by determining the proportion of female eggs laid and by hormonally biasing the development of female eggs into either a worker or reproductive form. This is the first time that such a dual system of queen influence over colony sex ratio is identified in an ant. 相似文献
530.
Michael Hrncir Sidnei Mateus Fábio S. Nascimento 《Behavioral ecology and sociobiology》2007,61(6):975-983
An efficient exploitation of carbohydrate food sources would be beneficial for social wasp species that store nectar within
their nest. In the swarm-founding polistine wasp Polybia occidentalis, we now demonstrate that the decisions of when and where to forage are influenced by information from conspecifics. Only
when foragers had been trained to collect at artificial carbohydrate feeders did newcomers (food-source-naive individuals)
continuously arrive at these feeders during 2 h of experiment. In control tests, in which no forager had been trained, not
a single newcomer alighted at any of the offered carbohydrate food sources. This indicates that, during the foraging process,
a nest-based input provided by successful foragers must have stimulated nestmates to search for food. Once activated, the
newcomers’ choice on where to collect was strongly influenced by field-based social information. The mere visual presence
of accumulated conspecifics (wasp dummies placed on one of the feeders) attracted newcomers to the food sources. Interestingly,
however, visual enhancement was not the only decision-biasing factor at the feeding site. In an experimental series where
searching wasps had to choose between the experimental feeder at which 3 foragers continuously collected and the control feeder
with nine wasp dummies, only 40% of the wasps chose the visually enhanced feeder. This points to the existence of additional
mechanisms of local enhancement. The possibility that, in social wasps, recruitment is involved in the exploitation of carbohydrate
food sources is discussed. 相似文献