全文获取类型
收费全文 | 190篇 |
免费 | 4篇 |
国内免费 | 32篇 |
专业分类
安全科学 | 26篇 |
废物处理 | 2篇 |
环保管理 | 15篇 |
综合类 | 51篇 |
基础理论 | 88篇 |
环境理论 | 1篇 |
污染及防治 | 18篇 |
评价与监测 | 9篇 |
社会与环境 | 3篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 21篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 2篇 |
2009年 | 13篇 |
2008年 | 20篇 |
2007年 | 13篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 31 毫秒
151.
Andrew G. Zink 《Behavioral ecology and sociobiology》2005,58(5):466-473
In species that exhibit extended parental care, females sometimes lay eggs communally in order to redistribute the costs of offspring care. Communal egg-laying often involves redundancy in female effort, such that the number of females contributing to reproduction is more than is needed to provide adequate parental care. As a result, a subset of females will often abandon the communal brood, with the time of departure ranging from immediate abandonment after egg-laying (brood parasitism) to delayed abandonment with prolonged care (cooperative breeding). In this paper I approach the parental care dynamics of female-female broods as a desertion game similar to that of mate desertion in species with bi-parental care. I describe a field study of the insect Publilia concava (Hemiptera: Membracidae), a species that exhibits communal oviposition and a full range of egg guarding. This species exhibits full redundancy in female care, with no difference in survival between singly and doubly guarded broods. I find that double guarding is extremely rare in the population, with most communal broods having only one female guard. While this guard was usually the female that initiated the brood, these same females were more likely to abandon when secondary females arrived and when secondary females exhibited longer guarding durations. Paradoxically, the secondary females usually abandoned the broods they visited, resulting in up to 50% of broods with double abandonment. These unguarded broods suffered a 50% reduction in hatching success, reflecting an important risk for primary females that abandon egg masses to secondary females. Overall, P. concava exhibits desertion dynamics similar to mate desertion in vertebrates and it is likely that the theoretical work in this area will be useful for future work that addresses the allocation of parental care among communal breeders. 相似文献
152.
Karen L. Wiebe 《Behavioral ecology and sociobiology》2005,57(5):429-437
Previous studies of biparental care in birds have focused on the males contribution and experimental removal of males. Woodpeckers, with a high level of paternal care including nocturnal incubation and brooding by males, offer a meaningful system in which to examine the importance of care by females. I studied the reproductive performance of 17 widowed male and 8 widowed female northern flickers (Colaptes auratus) relative to biparental (control) pairs. Of these single parents all widowed shortly after hatching, only one female abandoned its nest. Single parents boosted their provisioning rates to achieve 83% the provisioning rate of control broods, but reared significantly fewer young and young of poorer quality. However, single males, with 85% of the reproductive success of controls, were more successful than females with 43% the success of controls. Among widowed birds, a not significant lower survival was observed, but the chance of re-pairing with the same partner in a subsequent year was only 16% in the natural population, so long-term costs of desertion may be small. Although females seem to have the incentive and ability to desert, a lack of available males may constrain opportunities. This study demonstrates that when parental care roles are reversed in altricial birds, asymmetric benefits can favor female and not male desertion. 相似文献
153.
Competition with flies promotes communal breeding in the burying beetle,Nicrophorus tomentosus 总被引:3,自引:0,他引:3
Michelle Pellissier Scott 《Behavioral ecology and sociobiology》1994,34(5):367-373
Communal breeding through nest-sharing may benefit cooperating individuals indirectly, in increased inclusive fitness, or directly, when environmental constraints reduce the fitness of solitary breeders. Burying beetles provide extensive parental care and can breed either in pairs or in larger groups of unrelated males and females. Parentage of communally-reared broods is usually shared but is skewed in favor of the individuals of each sex that provide longer care. Females provide care longer than males, and two females are more likely to remain together in the brood chamber than two males are. Flies and other burying beetles are the major competitors for carcasses and this study suggests that it is competition with flies that promotes communal breeding inNicrophorus tomentosus On medium-size carcasses (35–40 g) the presence or absence of oviposition by flies had a significant effect on the size of the brood reared, and on large carcasses (55–60 g) the number of beetles present, two or four, had a significant effect on brood size. On both medium and large carcasses, pairs rearing broods on flyblown carcasses had fewer young than pairs on clean carcasses or foursomes on flyblown carcasses. There was a strong trend for an interaction effect between number of beetles and competition with flies (Table 1). Duration of parental care was not affected by competition with flies except for that of the first male to depart, which provided care longer on flyblown carcasses (Table 2). Pairs and foursomes were equally able to defend the carcass and brood from conspecific intruders and from larger intrudingNicrophorus orbicollis (Table 3). 相似文献
154.
三亚市水体中PPCPs的污染水平、分布特征及生态风险评价 总被引:4,自引:4,他引:0
环境中药物和个人护理用品(PPCPs)污染已引起全球性的关注,为了解热带滨海旅游城市三亚市的河流及主要海湾中PPCPs的污染水平、空间分布特征及其潜在环境风险,采用固相萃取和高效液相色谱串联质谱测定了三亚市主要河流和海湾中的11种典型PPCPs类物质.结果表明,由于三亚市在冬季和夏季接待旅游人数和降雨量的季节性变化,以及在冬季大量涌入以老年人为主的"候鸟"人口,使得三亚市主要河流中PPCPs浓度的季节性差异显著.冬季11种PPCPs检出率为100%,咖啡因(CFI)检出浓度最高为1449.10 ng·L-1,其次为美托洛尔(MTP)检出浓度最高为427.06 ng·L-1和罗红霉素(RTM)检出浓度最高为311.59 ng·L-1;夏季除磺胺甲唑(SMX)、磺胺噻唑(STZ)、泰乐菌素(TYL)、MTP和卡马西平(CBZ)的检出率在87.5%~93.75%,其余检出率为100%,CFI、MTP、RTM、红霉素(ETM)和氧氟沙星(OFL)浓度较高.主要海湾近岸海水中11种PPCPs均有检出,其中SMX、MTP和CBZ的检出率分别为85.7%、57.1%和71.4%,其余PPCPs检出率均为100%.CFI检出浓度最高,最大浓度为220.78 ng·L-1.运用风险商值模型(RQ)评价11种PPCPs在三亚市河流生态环境中的潜在风险,发现冬季STZ在月川桥采样点和RTM在凤凰路采样点,由于附近的医院以及污水处理厂出水排入,RQ值均>l,对水体的生态环境存在高风险.在夏季STZ在三亚大桥采样点、RTM在红沙码头采样点的RQ值介于0.1~1之间,对水体的生态环境具有潜在的中风险. 相似文献
155.
Nga Nguyen Russell C. Van Horn Susan C. Alberts Jeanne Altmann 《Behavioral ecology and sociobiology》2009,63(9):1331-1344
Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous
mammals. However, such associations [sometimes called “friendships” (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period.
The absence of mating exclusivity among “friends” suggests that males should invest little in infant care, raising questions
about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and
long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female
yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers
and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from
other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had
been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends
who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting
that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that
prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that,
for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining
friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study
is the first to find evidence that female primates gain social benefits from their early associations with adult males.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
156.
Both cooperation and conflict between the sexes are commonplace in monogamous mating systems. However, little is known about
how cooperation and competition varies seasonally in monogamous species that maintain permanent territories. We presented
territorial pairs of male and female New Zealand robins (Petroica australis) with a large supply of insect prey at monthly intervals for 2 years. Behavioural observations after food presentation were
then made to quantify seasonal and sexual differences in aggressive interactions over prey, prey acquisition rates, mate provisioning,
offspring provisioning, selfish food hoarding and cache retrieval. Data were used to evaluate sex-specific behavioural strategies
of mediating competition for food. Results showed that males aggressively excluded females from experimental food sources
year-round. Females only accessed food sources when males left them unattended. Consequently, females acquired fewer prey
than males. After controlling for differences in prey acquisition, both sexes consumed similar amounts of prey in the non-breeding
season. Even though males aggressively excluded females from accessing food sources directly, males fed large amounts of prey
to females during the breeding season. Both sexes provisioned young at similar rates. Males cached less prey than females
in the breeding season but more prey than females in the non-breeding season. Females showed similar caching intensities year-round.
Although males tried to defend their hoards, females frequently retrieved male-made caches. Overall, results showed that although
New Zealand robins cooperate to raise offspring during the breeding season, conflict between the sexes occurs year-round.
Males and females display different behavioural strategies to gain access to experimental food sources, which appear to lessen
male–female competition for food and evenly distribute food resources between the sexes. 相似文献
157.
Many species base their choice of mates on multiple signals which provide them with different kinds of information. Choosers
may assess the signals together to evaluate the overall quality of potential mates, but individuals often pay attention to
different signals in different contexts. In Rhinogobius brunneus, a fish displaying exclusive male parental care, females generally prefer males showing larger first dorsal fins (FDF) and
more active courtship displays as mates. Females choosing a mate usually initially assess the FDF and later utilize courtship
for the final decision. In our experiments, females with different hunger states used different signals when selecting mates.
Females in both hunger states preferred males with larger FDF in the first stage. In the second stage, well-fed females showed
highly repeatable choice, whereas poorly fed females responded only to variation in the courtship activity of males. The males
preferred by poorly fed females exhibited significantly higher offspring survival than nonpreferred males. Under conditions
of food shortage, males allocate more energy to future reproduction at the expense of the present brood, and females may prioritize
signals predictive of offspring survivorship over signals reflecting other aspects in male quality to minimize the losses
in direct benefits. We conclude that R. brunneus females may employ information from both signals but dynamically adjust their prioritization of each signal to current conditions
to ensure the choice that is currently most adaptive. 相似文献
158.
159.
Decamethylcyclopentasiloxane, commonly known as D5 (cyclopentasiloxane) has a wide application of use across a multitude of personal care product categories. The relative volatility of D5 is one of the key properties attributed to this substance that provide for the derived performance benefits from the use of this raw material in personal care formulations. On this basis, rapid evaporative loss following use of many products comprising D5 is expected following typical use application and corresponding wear time. 相似文献
160.
Do males and females differ in the feeding of large and small siblings? An experiment with the bluethroat 总被引:3,自引:0,他引:3
Per T. Smiseth Trond Amundsen Lars T. T. Hansen 《Behavioral ecology and sociobiology》1998,42(5):321-328
Males and females have been reported to differ in their feeding of large and small siblings in several species of birds.
According to recent hypotheses, this phenomenon may be related to a sexual conflict over avian hatching patterns. We designed
an experiment to test for the existence of such a sex difference by manipulating nestling size hierarchies of the bluethroat
(Luscinia s. svecica) in two directions; half the broods were “asynchronized” to yield large size-differences within broods and the other half
were “synchronized” to yield small size-differences. In all broods, nestlings were categorized as being either large or small
according to body mass. We recorded male and female food distribution by video early (day 4 after hatching) and late (day
8) in the nestling period. Males and females did not differ in their distribution of food among different-sized nestlings.
With large size-differences, both males and females fed large nestlings nearly twice as often as small ones. In contrast,
when the size-differences were small, food was more evenly distributed among nestlings. Early in the nestling period, males
fed more nestlings during each feeding visit than did females. Our finding that male and female bluethroats do not differ
in the feeding of large and small siblings is in contrast to most previous studies. Variation in costs and benefits to males
and females from feeding different-sized nestlings, and restrictions to parental choice due to nestling interactions, may
explain interspecific variation.
Received: 27 June 1997 / Accepted after revision: 26 January 1998 相似文献