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51.
L. W. Simmons 《Behavioral ecology and sociobiology》1990,27(1):43-47
Summary A recent debate has centred on the importance of paternal investment for the origin and maintenance of nuptial feeding in insects. Some authors have argued that the rates of nutrient incorporation are likely to be too slow to allow a male to fertilize the eggs that he helps to produce and cannot be considered as paternal investment. Here I report the results of some experiments that show that the positive effects of nutrient donation on female reproduction for one species of spermatophylax producing tettigoniid can be realized within 24 to 48 h. Furthermore, mating was found to induce a refractory period in the female that was longer than the time taken for the incorporation of nutrients and oviposition. Thus, the nurturant male is likely to fertilize the eggs even if last-male sperm precedence is high. The cost of spermatophylax production was manifest as a 5-day recovery period between matings. Thus males and their donations are likely to be limited resources for females resulting in a reversal of the typical sex roles. 相似文献
52.
L. W. Simmons 《Behavioral ecology and sociobiology》1987,21(5):313-321
Summary Females of the field cricket, Gryllus bimaculatus, are known to mate non-randomly with respect to male size. The reproductive output of females allowed to choose their mates was compared with that of females allocated mates. Females allowed to choose their mates laid a greater proportion of their available eggs, thereby investing more heavily in reproduction. Female choice did not appear to influence hatching success, suggesting that no short term benefits are derived from non-random mating. However, the offspring of females allowed to choose their mates developed more rapidly and began their own reproductive output before those of females who had been allocated mates. Furthermore, the faster developing offspring of females who chose their mates tended to have a consistantly higher survival rate as well as a lower variance in survival (i.e. less risk of mortality) at adult eclosion. Female choice may therefore contribute to offspring fitness and thus to long term reproductive success. Females allocated large males as mates did not equal those of females allowed to choose their mates, in terms of reproductive output and offspring fitness. This suggests that females may choose their mates with regard to a mixture of characters of which male size is only one. 相似文献
53.
Mussels as indicators of biological recovery zone 总被引:2,自引:0,他引:2
54.
55.
R. E. Simmons 《Behavioral ecology and sociobiology》1988,23(2):83-92
Summary Female northern harriers Circus cyaneus are polygynous, marsh-nesting raptors, whose mate choices are enigmatic. I determined the mate choice cues employed by females by correlating the order in which males were chosen with characters that 1) significantly influenced reproductive success; 2) were assessable prior to settlement; and 3) varied between breeding situations. Only nest sites and male provisioning performance met all these conditions: wet nest sites significantly (P<0.05) increased nest survival and high provisioning rates significantly (P<0.01) enhanced brood survival. The order in which females settled was strongly correlated with provisioning performance in both years (r
s
-0.65, and r
s
-0.84), but not with nest site quality. Females thus apperared to choose males principally on provisioning performance. Despite using the same cue, however, females choosing mated males reared only 0.28 young for every nestling raised by concurrently settling monogamous females (the lowest ratio recorded for any avian species). Extrapolation of male courtship provisioning patterns from clutch sizes and laying date indicated that females received similar proportions prior to and during egg-laying, but that males later preferentially fed females. Secondary females therefore chose mated males on the basis of a temporally changing and unreliable cue. The polyterritoriality, cooperative harems, skewed sex ratio, and sexy-son hypotheses were all inadequate in explaining polygyny in harriers. Female choice of mated males among harriers is best explained by the deceitful provisioning of food by males. 相似文献
56.
de Guzman NP Hendley P Gustafson DI van Wesenbeeck I Klein AJ Fuhrman JD Travis K Simmons ND Teskey WE Durham RB 《Journal of environmental quality》2005,34(3):793-803
The Acetochlor Registration Partnership (ARP) conducted a 7-yr ground water monitoring program at a total of 175 sites in seven states: Illinois, Indiana, Iowa, Kansas, Minnesota, Nebraska, and Wisconsin. While acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] was the primary focus, the analytical methods also quantified alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide], atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide], and two classes of soil degradates for acetochlor, alachlor, and metolachlor. Ground water samples were collected monthly for five years and quarterly for two additional years. All samples were analyzed for the presence of parent herbicides, and degradates were monitored during the last three years. Parent acetochlor was detected above 0.1 microg L(-1) in three or more samples at just seven sites. Alachlor and metolachlor were also rarely detected, but atrazine was detected in 36% of all samples analyzed. Even more widespread were the tertiary amide sulfonic acid (ethanesulfonic acid, ESA) degradates of acetochlor, alachlor, and metolachlor, which were detected at 81, 76, and 106 sites, respectively. The other class of monitored soil degradates (oxanilic acid, OXA) was detected less frequently, at 26, 16, and 63 sites for acetochlor OXA, alachlor OXA, and metolachlor OXA, respectively. The geographic distribution of detections did not follow the pattern originally expected when the study began. Rather than being a function primarily of soil texture, the detection of these herbicides in shallow ground water was related to site-specific factors associated with local topography, the occurrence of surface water drainage features, irrigation practices, and the vertical positioning of the well screen. 相似文献
57.
J. A. Kent. Simmons W. Berry. Lyons 《Journal of the American Water Resources Association》1994,30(6):983-991
ABSTRACT: The concentrations of dissolved fixed inorganic nitrogen (ΣN) in Bermuda ground waters can be very high due to both natural and anthropogenic processes. The high anthropogenic flux is due to domestic cesspit operation. Mass balance calculations indicate that ground water seepage, especially rich in ΣN, is a major source of nutrients into the near shore coastal zone of Bermuda. The ground water flux of ΣN is approximately 1.5 to 4 times that of the sewage flux of ΣN to Bermuda's nearshore waters. This input of ΣN may be important in the development of algal blooms in these waters. Our work, coupled with other recent investigations, suggests that the ground water input of nutrients into nearshore marine waters is an important process globally. 相似文献
58.
Patterns of fluctuating asymmetry in beetle horns: an experimental examination of the honest signalling hypothesis 总被引:6,自引:0,他引:6
Recent theoretical arguments have claimed that negative relationships between the size and symmetry of secondary sexual traits
are indicative of honest signalling of male quality. The patterns of fluctuating asymmetry in beetle horns have been proposed
to support the honest signalling hypothesis. Here we examine three assumptions of the hypothesis, (1) that traits are costly
to produce; (2) the levels of fluctuating asymmetry are indicative of stress imposed during development; and (3) that males
with larger traits should have more symmetrical traits, using the horned beetle, Onthophagus taurus. Experimental manipulations of brood mass were used to manipulate horn size and asymmetry. The development of horns was found
to be environmentally determined and costly in terms of delayed development and increased risk of pre-adult mortality. Decreasing
resource availability increased relative horn asymmetry. However, horn height was positively related to absolute horn asymmetry.
While the results do support the hypothesis that sexual selection on secondary sexual traits should increase levels of fluctuating
asymmetry, they provide no support for the notion that the patterns of asymmetry honestly signal male quality. Horns are used
in disputes between males and may be indicative of male parental investment. Thus, we conclude that while horn size may be
an indication of male quality, the patterns of fluctuating asymmetry are not.
Received: 16 December 1996 / Accepted after revision: 5 May 1997 相似文献
59.
Calling characteristics of parasitized and unparasitized populations of the field cricket Teleogryllus oceanicus 总被引:4,自引:0,他引:4
Summary Examination of three populations of the field cricket Teleogryllus oceanicus revealed the presence of an acoustically-orienting parasitoid fly, Ormia ochracea (Tachinidae), in the population of crickets that has been introduced to the Hawaiian Islands. The cricket is native to Australia and the Pacific, and the fly is native to North America but has also been introduced to Hawaii. Up to 27% of males and 7% of females in Hawaii were infested with fly larvae. Song structure in the parasitized Hawaiian population was distinct from that of the other two groups, with the Hawaiian crickets showing several reduced song parameters. In addition, onset and cessation of calling at dusk and dawn were more abrupt in the Hawaiian population. These results are consistent with selective pressure from the phonotactic flies to decrease risky calling. Silent males were present in all three populations, suggesting that these noncallers may not represent a unique adaptation to the parasitoid.
Correspondence to: M. Zuk 相似文献
60.
L. W. Simmons 《Behavioral ecology and sociobiology》1987,21(2):129-133
Summary Body size in the field cricket,Gryllus bimaculatus, contributes to fitness through its effects on competitive male mating success and female fecundity and is a character chosen
by females at mating. If females are to benefit from preferentially mating with large males they must be able to pass on the
advantages of large size to their offspring. The heritabilities of four aspects of body size were estimated by parent-offspring
regression. All aspects were shown to have heritable genetic variation despite the fact that theory predicts characters which
contribute to fitness should not be heritable. There may therefore be the potential for female choice in this species to be
adaptive. Some possible mechanisms for the maintenance of heritable variation are discussed. 相似文献