Author Keywords: behaviour; Colubridae; ecology; Masticophis flagellum; radiotelemetry; Reptilia; Serpentes; temperature; thermoregulation 相似文献
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101.
Examination of dispersional characteristics of Pratylenchus scribneri and Hoplolaimus galeatus indicated that there were patches within soybean fields in which both survival and reproduction wexe enhanced in spite of apparent homogeneity of soil type and topography. Treatment with carbofuran reduced the patchiness (or increased the dispersion) for H. galeatus while it had the opposite effect for P. scribneri. P. scribneri was less highly dispersed in conventional tillage plots than in the zero tillage plots. Populations from quadrats contained entirely within the patches could be described by the normal distribution (in the case of P. scribneri) or by the Poisson distribution (in the case of H. galeatus), while populations from quadrats contained entirely outside the patches could be described by the Poisson distribution for both nematodes. None of the distributions tested (Poisson, normal, negative binomial, Neyman''s) gave an adequate fit when populations from both inside and outside the patches were considered together. In all instances, log₁₀ and ln transformations reduced the goodness of fit of the data to all of the distributions tested. Even with logarithmic transformations, parametric statistics were not appropriate for analysis of data in most instances. 相似文献
102.
Mountain big sagebrush steppes in Wyoming have strong spatial patterning associated with topography. We describe the spatial variability of vegetation in a sagebrush steppe, and test the relationship between topography and vegetation using canonical correlation. Results of the analysis suggest that the main control over vegetation distribution in this system is wind exposure. Exposed sites are characterized by cushion plant communities and Artemisia nova, and less exposed sites by the taller sagebrush species Artemisia tridentata ssp. vaseyana. Topographic depressions and leeward slopes are characterized by aspen stands and nivation hollows. Measurements of soil microclimate suggest that a major influence of topographic position on vegetation is snow redistribution and its effect on soil moisture and temperature.Abbreviations ARNO
Artemisia nova
- ARTRW
Artemisia tridentata ssp. wyomingensis
- ARTRV
Artemisia tridentata ssp. vaseyana
- PUTR
Purshia tridentata
- RIP
riparian community
- POTR
Populus tremuloides
- NIV
nivation hollow community 相似文献
103.
Geoffrey A. Hammerson 《Journal of thermal biology》1989,14(4):219-224
1. 1.|Body temperature (Tb) and activity of the snake Masticophis flagellum were studied by radiotelemetry in an outdoor enclosure.
2. 2.|Mean diurnal Tb varied little over a wide range of weather conditions, but weather variation was accompanied by major changes in sun exposure and in the timing and duration of activity.
3. 3.|Recently fed snakes reduced activity and exhibited neither a thermophilic response nor increased precision of thermoregulation compared to fasting snakes.
104.
105.
D. RIVERA NUÑEZ C. OBON DE CASTRO F. TOMAS-LORENTE F. FERRERES F. A. TOMAS BARBERAN 《Botanical journal of the Linnean Society. Linnean Society of London》1990,103(4):325-349
RIVERA NUÑEZ, D., OBON DE CASTRO, C., TOMAS-LORENTE, F., FERRERES, F. & TOMAS-BARBERAN, F. A., 1990. Infrasectional systematics of the genus Sideritis L. section Sideritis (Lamiaceae). A new taxonomic division of the section Sideritis is proposed on the basis of morphological, cytological and chemical characters. The following subsections art-recognized: Grandiflora, Ovata, Camarae, Linearifolia, Gymnocarpae, Stachydioides, Lacaitae, Hirsuta, Chamaedryfolia, Arborescens, Flavovirens, Leucantha, Angustifolia, Serrata and Scordioides . Possible evolutionary pathways are discussed. 相似文献
106.
Summary A structural study of pollination in the dimorphic flowers ofCollomia grandiflora, a cleistogamous species, reveals significant differences in stigma behavior during pollination, stylar structure, the timing of generative cell division, and pollen tube growth rate patterns. The cleistogamous flower shows a loss of protandry and the stigma is receptive only after reflexing and closing of its lobes. In contrast, the chasmogamous stigma is receptive when reflexed and closes when pollen has been deposited on the lobes. Pollen tube penetration of the dry stigma papillae and entry into the style is similar in the two morphs. The chasmogamous style is solid and the cleistogamous style partly hollow. The matrix of secretion produced by the transmitting tract cells is mainly carbohydrate with a trace of lipids. It is fibrillar in nature and appears to be partly comprised of wall material from the transmitting tract cells. In the chasmogamous pollen, the generative cell enters the tube before division, which occurs between 30 and 60 min after pollination. This division correlates with an increased growth rate for the pollen tube. In the cleistogamous pollen, contact with the stigma triggers generative cell division inside the hydrated pollen grain before germination. The two resulting sperm cells exit the grain 15–30 min after pollination when the pollen tube is in the stigma lobes. The cleistogamous pollen tube shows only one phase of growth which occurs at a rate similar to that of the slow, first phase of the chasmogamous pollen.Abbreviations CH
chasmogamous
- CL
cleistogamous
- DAPI
4, 6-diamidino-2-phenylindole 相似文献
107.
WILKIN, P. J., 1989. The medicinal leech, Hirudo medicinalis (L.) (Hirudinea: Gnathobdellae), at Dungeness, Kent . An account of the ecology and conservation of the medicinal leech ( Hirudo medicinalis (L.)) at Dungeness, Kent, is presented. 相似文献
108.
David P. Watts 《International journal of primatology》1990,11(1):21-45
Understanding the principles that underly primate social evolution depends on integrated analysis of data on behavioral ecology, demography, life history tactics, and social organization. In this paper, data on the behavioral ecology of gorillas are reviewed and comparisons made among the three subspecies. Gorillas are selective feeders; and, their patterns of food choice are consistent with models of feeding by large generalist herbivores. They rely heavily on terrestrial herbaceous vegetation, which provides an abundant supply of densely distributed food. Availability of this food varies little in space and time; and, gorilla foraging activity can maintain its productivity. The level of frugivory and the extent of seasonal variation in diet and habitat use vary among and within populations. Low variability in food distribution patterns makes cooperative defense of foraging areas not worthwhile; but, it also means that ecological costs associated with gregariousness are low. However, demographic and life history data on mountain gorillas show that these costs may be sufficient to reduce female reproductive success as group size increases. Advantages to being with high quality males apparently can outweigh these costs. The implications of these data for the evolution of the mountain gorilla social system, and the possible roles of male protection, predation, and female/female competition in this regard, are discussed. 相似文献
109.
Fission-fusion social organization inAteles andPan 总被引:3,自引:0,他引:3
M. McFarland Symington 《International journal of primatology》1990,11(1):47-61
Recent research on the ecology and behavior of free-ranging spider monkeys (Ateles paniscus chamek) allows a more detailed comparison with the chimpanzee,Pan troglodytes, than has been possible previously. Despite their distant common ancestry, chimpanzees and spider monkeys share an unusual fission-fusion social system. In this paper, I compare subgroup size and composition, social unit structure, ranging behavior, patterns of philopatry and dispersal, and social relationships in the two taxa. It is proposed that spatial and temporal patchiness in food dispersion and abundance, resulting in a high-level of feeding competition between females within a group, has been the most important ecological selection pressure leading to the evolution of fission-fusion social organization in both species. 相似文献
110.
James R. Griesemer 《Biology & philosophy》1990,5(1):3-36
Accounts of the relation between theories and models in biology concentrate on mathematical models. In this paper I consider
the dual role of models as representations of natural systems and as a material basis for theorizing. In order to explicate
the dual role, I develop the concept of a remnant model, a material entity made from parts of the natural system(s) under
study. I present a case study of an important but neglected naturalist, Joseph Grinnell, to illustrate the extent to which
mundane practices in a museum setting constitute theorizing. I speculate that historical and sociological analyses of institutions
can play a specific role in the philosophical analysis of model-building strategies. 相似文献