全文获取类型
收费全文 | 355篇 |
免费 | 28篇 |
国内免费 | 5篇 |
出版年
2023年 | 6篇 |
2022年 | 1篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 29篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 17篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有388条查询结果,搜索用时 312 毫秒
1.
Robert A. Krebs 《Journal of Insect Behavior》1991,4(2):221-233
Variation in copulation duration of Drosophila mojavensisstrains was influenced by both sexes. Males maintained predominant control, as copulation duration of pairs from different strains was more similar to that of the strain from which the male was derived, but female origin also contributed significantly to the duration of copulation. Variation among strains was controlled by genes acting additively in both sexes. The size of both males and females also affected copulation duration. Small males copulated longer on average than large males, while males paired with large females copulated longer than those paired with small females. The importance of copulation duration to fitness was tested by correlation analyses with male size, female size, female remating latency, and number of eggs laid prior to female remating. Longer copulations stimulated earlier oviposition, possibly by increasing accessory gland secretions that are passed by males during copulation. 相似文献
2.
Donald W. Misch Leroy M. Anderson Lewis R. Boobar 《Entomologia Experimentalis et Applicata》1987,44(2):151-154
The toxic effect of a spore preparation of Bacillus thuringiensis var. israelensis Berliner Serotype H-14 (Bti) on 4th instar larvae of Aedes aegypti L. and Toxorhynchites amboinensis (Doleschall) was observed when given either in a suspension feeding test or when injected orally as a forced feeding or via the anus as an enema. The A. aegypti larvae showed the greater sensitivity to Bti both because they greatly concentrate the toxin by filter feeding and they are more sensitive to Bti than are the larvae of T. amboinensis. The latter appeared approximately two-fold less sensitive to Bti than the former after taking into account their greater body weight.
Résumé La toxicité sur des larves de 4ème stade de A. aegypti et T. amboinensis, d'une préparation de spores de B. thuringiensis var. israelensis Berliner sérotype H-14, a été examinée après: injection orale par alimentation forcée, injection anale comme lavement, — le témoin étant une alimentation à partir d'une suspension de spores.Les larves de A. aegypti ont présenté la plus grande sensibilité au Bti d'une part parce qu'elles concentrent beaucoup la toxine avec leur alimentation par filtration, et parce qu'elles sont plus sensibles sensu stricto au Bti. Même en tenant compte de leur poids plus élevé, T. amboinensis est apparu comme deux fois moins sensible au Bti.相似文献
3.
Daniel Q. Estep Thomas P. Gordon Mark E. Wilson Margaret L. Walker 《International journal of primatology》1986,7(5):507-517
Copulatory data derived from observations of social groups of rhesus and stumptail macaques were analyzed to test the hypothesis
that pairs of animals would resume copulation significantly sooner if a second male copulated with the female shortly after
the first male’s ejaculation. Data from both groups supported the hypothesis. These results, extending previous studies in Macaca nemestrina,suggest that the shortening of copulatory intervals by social stimuli occurs in several species, both in social groups and
in experimentally created triads. These findings also are consistent with the hypothesis that socially mediated resumption
of mating is related to intrasexual competition among males. 相似文献
4.
This paper summarizes the processing of small enchytraeid species for cinematographic documentation and covers the main details of a film on their locomotion, food uptake, anatomy and reproductive biology. This includes copulation, shedding of the cocoon and hatching of the young, characteristic reproductive patterns for all clitellate worms. 相似文献
5.
J. Sabater Pi M. Bermejo G. Illera J. J. Vea 《International journal of primatology》1993,14(5):797-804
For the first time, three cases of capture and forced interaction were observed between bonobos (Pan paniscus)and two other species of primates (Colobus angolensisand Cercopithecus ascanius)in the Lilungu (Ikela) region, Republic of Zaire. The bonobos interacted with the captured primates as if they were dealing with individuals of their own species. They sought cooperation in their interactions with the captured young primates without scccess. There is no evidence that they ate the captives. 相似文献
6.
Yasuhiro Takemon 《Ecological Research》1993,8(2):185-192
Water drinking habits during flight in adult mayflies ofEpeorus ikanonis Takahashi were observed and the effect of water intake on their longevity was examined. The study was carried out in a mountain
stream in western Japan. Adult males collected a water droplet under the head capsule while alighting on the water surface
and consumed it after moving to nearby riparian vegetation. The amount of water intake was experimentally estimated to be
9.7% of the bodyweight for males. Although females did not show the water drinking behavior in the field, they imbibed as
much as 5.5% of the bodyweight of water in an experimental situation. Morphological observation of the mouthparts revealed
that the water was drawn in through the pits at the base of the labrum. In the field caging experiment, males with a water
supply had a substantially longer life span than those without. Increase in adult life span by drinking water was less marked
in females. Multiple copulation was observed in both sexes during the experiment. The water drinking behavior of the males
may closely relate to mating success through increased longevity. Variation in the longevity of adult mayflies was discussed
with regard to the possibility of water intake.
This paper forms part of a PhD thesis submitted to the Department of Zoology in Kyoto University (1990). 相似文献
7.
The lifetime mating frequency of female butterflies is believed tobe dependent on the reproductive status of the males which they have mated. This report assesses those status usingPieris rapae L. Multiple mating females mated males with a short time interval after the last mating or males with many mating records. Such males, like small ones, produced small spermatophores during copulation, which may have resulted in high mating frequency of those females. The males with short time interval after the last mating or those with many mating records also showed a long mating duration. Alternative interpretations of the adaptive significance of this behavior for males are discussed. 相似文献
8.
Time constraints are critical for reproductive success. To understand the spatiotemporal dynamics of morph frequency in the female‐dimorphic damselfly Ischnura senegalensis, we compared two different morphs for two important time constraints on female reproductive output, i.e. post‐emergence sexual maturation and prolonged copulation. The females of both morphs achieved sexual maturation 4–5 days after emergence, suggesting that the rate of sexual mutation does not result in morph‐specific fitness. The copulation durations declined with the time of onset of copulation in both morphs. Consequently, all copulations terminated at approximately 12:00 hours. Because females show foraging and oviposition activity only after copulation, the copulation duration does not result in morph‐specific time constraints. These two important time constraints do not account for morph‐specific reproductive success and do not affect the evolutionary equilibrium of morph frequency in I. senegalensis. 相似文献
9.
Xiaoyu Yang Wei Xu Svetlana Dukleska Sabrina Benchaar Selina Mengisen Valentyn Antochshuk Jason Cheung Leslie Mann Zulfia Babadjanova Jason Rowand Rico Gunawan Alexander McCampbell Maribel Beaumont David Meininger Daisy Richardson Alexandre Ambrogelly 《MABS-AUSTIN》2013,5(5):787-794
Monoclonal antibodies constitute a robust class of therapeutic proteins. Their stability, resistance to stress conditions and high solubility have allowed the successful development and commercialization of over 40 antibody-based drugs. Although mAbs enjoy a relatively high probability of success compared with other therapeutic proteins, examples of projects that are suspended due to the instability of the molecule are not uncommon. Developability assessment studies have therefore been devised to identify early during process development problems associated with stability, solubility that is insufficient to meet expected dosing or sensitivity to stress. This set of experiments includes short-term stability studies at 2−8 þC, 25 þC and 40 þC, freeze-thaw studies, limited forced degradation studies and determination of the viscosity of high concentration samples. We present here three case studies reflecting three typical outcomes: (1) no major or unexpected degradation is found and the study results are used to inform early identification of degradation pathways and potential critical quality attributes within the Quality by Design framework defined by US Food and Drug Administration guidance documents; (2) identification of specific degradation pathway(s) that do not affect potency of the molecule, with subsequent definition of proper process control and formulation strategies; and (3) identification of degradation that affects potency, resulting in program termination and reallocation of resources. 相似文献
10.
Reuven Dukas Janice L. Yan Andrew M. Scott Surabhi Sivaratnam Carling M. Baxter 《Evolution; international journal of organic evolution》2020,74(6):1112-1123
Forced copulation is an extreme form of sexual aggression that can affect the evolution of sex-specific anatomy, morphology, and behavior. To characterize mechanistic and evolutionary aspects of forced copulation, we artificially selected male fruit flies based on their ability to succeed in the naturally prevalent behavior of forced matings with newly eclosed (teneral) females. The low and high forced copulation lineages showed rapid divergence, with the high lineages ultimately showing twice the rates of forced copulation as the low lineages. While males from the high lineages spent more time aggressively pursuing and mounting teneral females, their behavior toward non-teneral and heterospecific females was similar to that of males from the low lineages. Males from the low and high lineages also showed similar levels of male-male aggression. This suggests little or no genetic correlations between sexual aggression and non-aggressive pursuit of females, and between male aggression toward females and males. Surprisingly however, males from the high lineages had twice as high mating success than males from the low lineages when allowed to compete for consensual mating with mature females. In further experiments, we found no evidence for trade-offs associated with high forced mating rates: males from the high lineages did not have lower longevity than males from the low lineages when housed with females, and four generations of relaxed selection did not lead to convergence in forced mating rates. Our data indicate complex interactions among forced copulation success and consensual mating behavior, which we hope to clarify in future genomic work. 相似文献