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Analyses of knowledge gaps can highlight imbalances in research, encouraging greater proportionality in the distribution of research efforts. In this research we used generalized linear mixed models (GLMM) with the aim to determine if research efforts for the period 2005–2015 for terrestrial vertebrates of Amphibia, Aves, Mammalia and Reptilia in the South Pacific region were correlated with conservation status (critically endangered (CR), endangered (EN), vulnerable (VU), least concern (LC) and near threatened (NT)) or population trends (increasing, stable, decreasing and unknown) through the International Union for Conservation of Nature (IUCN) database. Our results showed that research distribution was uneven across different classes. Out of 633623 investigated papers, the average number of publications per species was 43.7, 306.7, 717.6 and 115.3 for Amphibia (284 species), Aves (1306 species), Mammalia (243 species) and Reptilia (400 species), respectively. Consistently, the lower publication effort on Amphibia compared to other taxonomic classes was revealed as significant by GLMM analysis. There was no significant differences in research effort among levels of conservation status. However, we found significantly different publication efforts among population trends of all examined species in that species with “unknown” population trends gained significantly lower researchers’ attention compared to species with “decreasing” trend. Results also indicated that, although it was not significant, the highest attention is given to species with “increasing” population trend over all taxonomic classes. Using the Information Theoretic approach we also generated a set of competing models to identify most important factors influencing research efforts, revealing that the highest ranked model included taxonomic class and population trend.  相似文献   
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 The flowering of Clutia pulchella was studied in a coastal scarp forest community in southern KwaZulu-Natal, South Africa. Sex dependent differences in the frequency and magnitude of floral output were recorded, with male individuals producing 4.32 times more flowers per leaf axis than females. Increased node production, as a manifestation of significantly increased branching, allowed for prolific flower production in males. Energy investment per flower was marginally greater in females (0.045 J/mg), despite copious pollen production and glandular secretion in males (0.035 J/mg). Differential flower production, reproductive organ dry mass and an unbalanced branching ratio revealed that “per plant” expenditure towards flowering was more pronounced in males (♀ flowering × 5.04). The elevated cost of fruit production (♀ flowering × 5.5), inclusive of imperfect fruit set, resulted in overall reproductive expense being slightly higher for females. Such sex-dependent reproductive investment was shown to have minimal influence on the population sex ratio, with sex frequencies and nearest neighbor distances yielding a non-significant male bias of 1.16. No evidence of spatial asymmetry was found. Received December 1, 1999 Accepted September 27, 2000  相似文献   
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The ocean pout copulates through direct genital contact for internal fertilization. A complete spawning event consists of copulation, oviposition, and the female displaying parental care by wiping and wrapping herself around the eggs.  相似文献   
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The social organization of cooperatively breeding species is extremely variable, with diverse social group composition and patterns of relatedness. Species that exhibit alternative routes to helping within the same population are potentially useful systems to investigate the causes and fitness consequences of diverse evolutionary pathways to cooperative behaviour. In this study, we use microsatellite markers and field observations to describe helping behaviour and patterns of relatedness in the unusual cooperative breeding system of the rifleman Acanthisitta chloris. First, we show that rifleman helpers consist of a remarkably diverse demographic, including males and females, who may be adult or juvenile, failed breeders or nonbreeders, or even successful breeders that simultaneously feed their own brood. Adult helpers mostly helped at first‐brood nests, while first‐brood juveniles assisted their parents at second broods. Second, we show that rifleman pairs are strictly sexually monogamous, and helpers did not gain any current reproductive success through helping. Third, genotyping showed that contrary to previous assumptions, helpers were closely related to the recipients of their care and preferentially directed care towards relatives over contemporaneous nests of nonrelatives. Finally, we show that variation in helper provisioning effort was attributed to age: juvenile helpers provisioned less than adults and were less responsive to the demands of a growing brood. Overall, our results show that the diverse routes to helping in this unusual species are driven by the common theme of kinship between helper and recipients, resulting in a previously underestimated potential for helpers to gain indirect fitness benefits.  相似文献   
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Most research on mate choice in modern societies is based on data that may or may not reflect actual mating behavior (e.g., stated preferences, personal advertisements). In the present study, real-life matings were reported by a large representative sample of men and women (N = 1,133). These data were used to test an evolutionary model in which mate choice is hypothesized to depend on resources potentially contributed to reproduction by each sex. Consistent with the model, it was found that (a) men (but not women) of higher social status acquire more mating partners, suggesting that male status is an important criterion in female choice; (b) women’s (but not men’s) number of partners decreases linearly with age, suggesting that female reproductive potential is an important criterion in male choice; and (c) women (but not men) display a significant relationship between marital dissolution and promiscuity, suggesting that female sexual exclusivity is an important criterion in male choice. These results are discussed in relation to understanding mate choice mechanisms from behavioral data. Daniel Pérusse is an assistant professor in the Department of Anthropology at the Université de Montréal. His research interests include the evolutionary biology of human social and reproductive behavior, sexual selection theory, and biocultural evolution. His current research bears on human socialization processes and psychosocial development from an evolutionary and behavior-genetic perspective. Recent publications include “Cultural and Reproductive Success in Industrial Societies: Testing the Relationship at the Proximate and Ultimate Levels” (Behavioral and Brain Sciences 16(2):267–322, 1993) and “Human Parental Behavior: Evidence for Genetic Influence and Potential Implications for Gene-Culture Theory” with M. C. Neale, A. Heath, and L. J. Eaves (Behavior Genetics, in press).  相似文献   
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Zusammenfassung Junge Graukraniche haben einen weniger guten Jagderfolg bzw. eine geringere Rate bei der Nahrungsaufnahme als Altvögel. Dieses Defizit sollte durch die elterliche Investition bei der Jungenaufzucht kompensiert werden. Untersuchungen zum Zeitbudget und zum Aufwand aus dem Brutgebiet fehlen bisher. Mit Hilfe markierter Jungkraniche (Farbringe, Sender) wurde das Verhalten der Eltern und ihrer Nachkommen erfasst, um die Investitionen in Beziehung zum Reproduktionserfolg zu analysieren. Die Eltern sicherten mit 39,6% fast viermal so häufig wie Altvögel ohne Junge (Übersommerer). Bei Paaren mit zwei Nachkommen waren diese Aufwendungen höher als bei Paaren mit nur einem Jungvogel. Das Weibchen profitierte vom verstärkten Sichern des Männchens (Männchen: durchschnittlich 43,9%, Weibchen 35,3%) und konnte so vermutlich schneller seine Investition in die Gelegeproduktion ausgleichen. Die Revierverteidigung bzw. Feindabwehr übernahmen meist die Männchen. Die Beteiligung des Männchens förderte den Aufzuchterfolg, der auf zwei Junge begrenzt ist. Die Jungen profitierten von den Leistungen ihrer Eltern. Sie konnten mit geringem Sicherungsaufwand (11,9%) Nahrung suchen (67,7%, Eltern 42,8%) und so ihre geringere Aufnahmerate kompensieren. 77,9% der Jungkraniche überlebten vom Zeitpunkt des Markierens im Juni bis zum Abzug ins Überwinterungsgebiet im Oktober/November (84% der Einzeljungen und 75% bei Familien mit zwei Nachkommen).Junge Kraniche müssen einen wesentlichen Teil des Tages Nahrung aufnehmen, um den Energiebedarf für ein schnelles Wachstum sicherzustellen. Bei einer negativen Energiebilanz aufgrund zu vieler Störreize können die Erfolge bei der Jungenaufzucht sinken. Im Rahmen der Landschaftsplanung ist vor allem in Räumen mit einer hohen Siedlungsdichte des Kranichs auf eine stärkere Bebauung (z. B. mit Windkraftanlagen) oder Zerschneidung durch weitere Verkehrswege und Energieleitungen zu verzichten.
Behaviour of Crane (Grus grus) families in their breeding territories in Northeast Germany: parental care and investment
Summary Juveniles and immature birds normally have less foraging ability and a lower food intake rate than adults. This — it has been presumed — is compensated for by parental care and investment during juvenile development. Studies of time budgets and parental investment of Common Cranes were carried out in the years 1995 to 1999 in Northeast Germany. Having first marked young Cranes (colour rings, radio transmitters), we analysed the behaviour of parents and offspring to correlate this with reproductive success. Parents with young (39.6%) were four times more vigilant than non-breeders. The investment of pairs with two young was significantly (p<0.001) higher than in pairs with only one young. Females profited from the high vigilance rate of their males (males mean 43.9%, females 35.3%) and were thus able probably to compensate for their investment in the clutch faster because of higher food intake. Defence of the territory against other cranes and defence against predators were tasks mostly undertaken by males. If the males participated in the rearing of the young, the pair were able to rear two juveniles to fleding.The young profited from parental care. They were able to feed most of the time (67.7%) with lower vigilance costs (11.9%; 27.7% less than parents), and thus possibly compensated for their lower feeding success. Rearing of two young, however, must be the upper limit of possible investment of adults. So far there has been no evidence of families with three grown-up young in a stopover region or on the wintering grounds. The survival of juveniles from the date of ringing in June up to the migration to the wintering sites in mid-November amounts to 77.9%, with 84% for families with one young and 75% for those with two young. Accordingly the reproductive success was higher for pairs with two young (1.32 juv./pair) than with one young (0.84 juv/pair).The long-term survival of the population in a man-made landscape is only possible with an appropriate reproductive success. The offspring of crane families have to feed throughout the major part of the day in order to gain their energy for the high metabolic rate during growth. With a negative energy balance because of too much disturbance, the reproductive success will decrease. Future landscape planning should avoid new traffic structures, buildings (e.g. wind turbines) or power lines at least in areas of high crane density.
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