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41.
42.
潮汕地区农药植物资源十分丰富。初步调查统计共有 88科 2 39种 ,其中蕨类植物 4种 ,裸子植物 6种 ,被子植物2 2 9种 ,这些农药植物均具有杀虫作用。本文对潮汕地区农药植物的研究和合理开发利用提出了若干建议 相似文献
43.
Spatial patterns, temporal variability, and the role of multi-nest colonies in a monogynous Spanish desert ant 总被引:1,自引:0,他引:1
Abstract 1. The colonies of the Spanish desert ant Cataglyphis iberica are polydomous. This study describes the temporal and spatial patterns of the polydomy in this species at two different sites, and presents analyses of its role in reducing the attacks of the queen over sexual brood, and in allowing better habitat exploitation.
2. The spatial distribution of nests was clumped while colonies were distributed randomly. Mean nearest neighbour distance ranged from 3.4 to 7.0 m for nests and from 12.3 to 14.1 m for colonies. Distance of foragers searching for food varied among nests: mean values were between 6.1 and 12.6 m.
3. At both sites, the maximum number of nests per colony occurred in summer, during the maximum activity period of the species. Colonies regrouped at the end of this period but overwintered in several nests.
4. Nest renewal in C. iberica colonies was high and showed great temporal variability: nests changed (open, close, re-open) continuously through the activity season and/or among years. The lifetime of up to 55% of nests was only 1–3 months.
5. Polydomy in C. iberica might decrease the interactions between the queen and the sexual brood. In all colonies excavated just before the mating period, the nest containing the queen did not contain any virgin female. Females were in the queenless nests of the colony.
6. The results also suggest that polydomous C. iberica colonies may enhance habitat exploitation because foraging activity per colony increases with nest number. The relationship between total prey input and foraging efficiency and number of nests per colony attains a plateau or even decreases after a certain colony size (four to six nests). This value agrees with the observed mean number of nests per colony in C. iberica . 相似文献
2. The spatial distribution of nests was clumped while colonies were distributed randomly. Mean nearest neighbour distance ranged from 3.4 to 7.0 m for nests and from 12.3 to 14.1 m for colonies. Distance of foragers searching for food varied among nests: mean values were between 6.1 and 12.6 m.
3. At both sites, the maximum number of nests per colony occurred in summer, during the maximum activity period of the species. Colonies regrouped at the end of this period but overwintered in several nests.
4. Nest renewal in C. iberica colonies was high and showed great temporal variability: nests changed (open, close, re-open) continuously through the activity season and/or among years. The lifetime of up to 55% of nests was only 1–3 months.
5. Polydomy in C. iberica might decrease the interactions between the queen and the sexual brood. In all colonies excavated just before the mating period, the nest containing the queen did not contain any virgin female. Females were in the queenless nests of the colony.
6. The results also suggest that polydomous C. iberica colonies may enhance habitat exploitation because foraging activity per colony increases with nest number. The relationship between total prey input and foraging efficiency and number of nests per colony attains a plateau or even decreases after a certain colony size (four to six nests). This value agrees with the observed mean number of nests per colony in C. iberica . 相似文献
44.
野生香料植物小鱼仙草资源开发利用 总被引:4,自引:0,他引:4
利用GC -MS -DC及计算机联用技术对小鱼仙草全草挥发油的成分进行分析研究 ,结果表明小鱼仙草挥发油主要成分为 :香荆芥酚 ,百里香酚、1,8-桉叶油素、侧柏酮、丁香烯、草烯和檀香烯等。不同产地 ,其挥发油成分存在一定的相似性 ,又具有较大差异。种子油中含有大量人体必需不饱和脂肪酸 :亚麻酸、油酸和亚油酸等 ,其种子油和种子具有较高的营养价值 ,值得进一步开发利用。其挥发油在香精香料、医药、化妆品等行业具有广大开发利用前景 相似文献
45.
云南食用菌资源应用开发前景与展望 总被引:12,自引:0,他引:12
从栽培食用菌和野生食用菌两方面综述了云南食用菌的资源状况 ,通过对云南食用菌研究、开发现状的总结 ,就其存在的问题提出了相应的建议。简述了食用菌资源在云南应用开发中的广阔前景 ,并提出可持续利用发展的战略。 相似文献
46.
L. E. Ehler 《BioControl》2002,47(3):309-325
Natural enemies associated with eggs of >Nezara viridula (L.) (Heteroptera: Pentatomidae) wereevaluated by placing sentinel egg masses inweeds and cultivated tomato and bean crops innorthern California. Egg predation wasgenerally less than 10% and normally involvedpredators with chewing mouth parts. Predatorsseldom destroyed an entire egg mass, typicallyeating <40 eggs per exploited mass.Laboratory evaluation of >25 species ofpotential arthropod predators revealed that fewfed on >N. viridula eggs to any extent;however, numerous species fed on >N.viridula nymphs. Five species of eggparasites were recovered from sentinel eggmasses: >Trissolcus basalis (Wollaston),>Gryon obesum Masner and >Telenomuspodisi Ashmead (Scelionidae); and>Ooencyrtus californicus Girault and >O.johnsoni (Howard) (Encyrtidae). The major eggparasite was >T. basalis, the only exoticmember of the parasite guild; it typicallyparasitized 100% of the eggs in an exploitedegg mass. The results indicate thatparasitization of eggs and predation of smallnymphs can be important biotic mortalityfactors for >N. viridula populations innorthern California. It is suggested that acombination of factors – viz., eggparasitization, nymphal predation, regionalshortage of overwintering sites, and localshortages of suitable hosts – maintains thisexotic pest at relatively low levels in theregion. 相似文献
47.
Alejandro H. Buschmann Juan A. Correa Renato Westermeier María A. Paredes Diego Aedo P. Potin Gesica Aroca Jessica Beltrán María C. Hernández-González 《Journal of applied phycology》2001,13(3):253-265
This study integrates landings statistics and biological studies of the red algaGigartina skottsbergii Setchell & Gardner. The analysis of the landings and carrageenan production in Chile suggeststhat this resource will suffer a strong harvesting pressure during the nextyears. Biological results on sporulation, germination, sporeling growth and survivorship in laboratory,indoor tanks and field conditions, indicated that cultivation of this species istechnically feasible, as spores can be seeded on ropes and other substrata. Vegetative propagation of this species through tissue fragmentationis also possible. Vegetative fragments of this carrageenophyte have 20 to30% higher growth rates than whole fronds in suspended culture systems. Protoplast production can be also explored for bypassing restrictions inspore availability. Major advantages that encourage the cultivation of G. skottsbergii include its gel quantity and quality, its pathogen-freecondition, a high reproduction potential and its regeneration capacity. Onthe other hand, the major constraints are related to its relatively slowgrowth as compared to other carrageenophytes, limited availability ofspores and high mortality during juvenile stages. 相似文献
48.
John Boreman 《Environmental Biology of Fishes》1997,48(1-4):399-405
Sturgeons and paddlefish exhibit unusual combinations of morphology, habits, and life history characteristics, which make them highly vulnerable to impacts from human activities, particularly fisheries. Five North American sturgeons (shortnose, Gulf, pallid, Alabama, and green sturgeon) are listed as endangered or threatened by management authorities. Managers have instituted fishery closures for the three other species of North American sturgeons (Atlantic, white, and shovelnose) and paddlefish because of low stock abundance at some point in this century. Reproductive potential in four species I examined (Atlantic, white, and shortnose sturgeon, and paddlefish) is more sensitive to fishing mortality than it is for three other intensively-fished coastal species in North America: striped bass, winter flounder, and bluefish. The sturgeons and paddlefish are generally longer-lived than the three other coastal species, and also have an older age at full maturity, lower maximum fecundity values, and older ages at which 50% of the lifetime egg production is realized with no fishing mortality. 相似文献
49.
Elevationally biased avian predation as a contributor to the spatial distribution of geometrid moth outbreaks in sub‐arctic mountain birch forest 下载免费PDF全文
ADAM A. PEPI OLE PETTER L. VINDSTAD MALIN EK JANE U. JEPSEN 《Ecological Entomology》2017,42(4):430-438
1. Population dynamics and interactions that vary over a species' range are of particular importance in the context of latitudinal clines in biological diversity. Winter moth (Operophtera brumata) and autumnal moth (Epirrita autumnata) are two species of eruptive geometrids that vary widely in outbreak tendency over their range, which generally increases from south to north and with elevation. 2. The predation pressure on geometrid larvae and pupae over an elevational gradient was tested. The effects of background larval density and bird occupancy of monitoring nest boxes on predation rates were also tested. Predation on larvae was tested through exclusion treatments at 20 replicate stations over four elevations at one site, while pupae were set out to measure predation at two elevations at three sites. 3. Larval densities were reduced by bird predation at three lower elevations, but not at the highest elevation, and predation rates were 1.9 times higher at the lowest elevation than at the highest elevation. The rate of predation on larvae was not related to background larval density or nest box occupancy, although there were more eggs and chicks at the lowest elevation. There were no consistent differences in predation on pupae by elevation. 4. These results suggest that elevational variation in avian predation pressure on larvae may help to drive elevational differences in outbreak tendency, and that birds may play a more important role in geometrid population dynamics than the focus on invertebrate and soil predators of previous work would suggest. 相似文献
50.