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31.
We describe primers and polymerase chain reaction conditions to amplify 100 microsatellite loci from the Siberian jay (Perisoreus infaustus). The primers were tested on two geographically separated Finnish populations. The developed primer pairs yielded an average of 4.72 alleles per locus (range one to 17) and an average observed heterozygosity of 0.55 (range 0.04 to 1). 相似文献
32.
Felix Schlagintweit 《Facies》2008,54(3):377-402
Examples of bioerosional processes (boring patterns) are described from shallow-water limestones of the Late Jurassic Plassen
Carbonate Platform (PCP) and the Late Cretaceous to Paleocene Gosau Group of the Northern Calcareous Alps, Austria. Some micro-/macro-borings
can be related to distinct ichnotaxa, others are classified in open nomenclature. In the Alpine Late Jurassic, bioerosional
structures recorded from clasts in mass-flows allow palaeogeographical conclusions concerning the source areas. In particular,
these are borings of the Trypanites-ichnofacies detected from clasts (Barmstein limestones) of the PCP or special type of bored ooids of unknown source areas
or restricted autochthonous occurrences. In the Lower Gosau Subgroup, Gastrochaenolites macroborings occur in mobile carbonate clast substrates of shore zone deposits (“Untersberg Marmor”). Different types of
borings are recorded from rudist shells and coral skeleton, some of which are referable to the ichnotaxon Entobia produced by endolithic sponges. In the present study, special attention is paid to the occurrences of the cryptobiotic foraminifera
Troglotella incrustans Wernli and Fookes in the Late Jurassic and Tauchella endolithica Cherchi and Schroeder in the Late Cretaceous. The latter is so far only known to be from the Early Cenomanian of France and
is reported here for the first time from the Late Turonian-Early Coniacian stratigraphic interval where it was found in turbulent
carbonate deposits within borings penetrating bivalve shells or coralline algae. The records of cryptobiotic foraminifera
from the Northern Calcareous Alps are supplemented by a single finding from the Middle Cenomanian of SE France. A palaeoenvironmental
interpretation of the occurrences of the cryptobiotic foraminifera is provided. 相似文献
33.
Magorzata Jefimow Micha Wojciechowski Atsuko Masuda Tadashi Oishi 《Journal of thermal biology》2004,29(7-8):641-647
We investigated the correlation between torpor frequency and capacity for non-shivering thermogenesis (NST) in Siberian hamsters (Phodopus sungorus) during 25 weeks of acclimation to cold and short days. We hypothesized that torpor use is conditioned on the development of brown adipose tissue (BAT) capacity for NST. We found that (1) the degree of noradrenaline (NA)-induced hyperthermia was positively correlated with torpor frequency and its length and depth, and (2) the maximum response to NA occurred at the time of day when hamsters naturally arouse from torpor. The present study quantifies the correlation between torpor frequency and NST capacity and we suggest that a well-developed NST capacity is a prerequisite for the occurrence of torpor. 相似文献
34.
Oxygen consumption of East Siberian cod: no support for the metabolic cold adaptation theory 总被引:2,自引:0,他引:2
Standard metabolic rate ( R s ) at 2°C of eight East Siberian cod Arctogadus borisovi , caught in West Greenland, body mass of 601.5 ± 147.6 g (mean ± s.D.), was 40.9 ± 5.9 mg O2 kg-1 h-1 and 59.0 ± 6.6mg O2 kg-1 h-1 when extrapolated to a standardized 100 g fish. R s was compared with three other Gadidae, to test the theory of metabolic cold adaptation (MCA). There was no evidence of MCA in the family. 相似文献
35.
Franz T. Fürsich Markus Wilmsen Kazem Seyed-Emami Gerhard Schairer Mahmoud R. Majidifard 《Facies》2003,48(1):171-198
Summary Following a phase of predominantly siliciclastic sedimentation in the Early and Middle Jurassic, a large-scale, low-latitude
carbonate depositional system was established in the northern part of the Tabas Block, part of the central-east Iranian microplate,
during the Callovian and persisted until the latest Oxfordian/Early Kimmeridgian. Running parallel to the present eastern
block margin, a NNW/SSE-trending carbonate platform developed in an area characterized by reduced subsidence rates (Shotori
Swell). The growth of this rimmed, flat-topped barrier platform strongly influenced the Upper Jurassic facies pattern and
sedimentary history of the Tabas Block. The platform sediments, represented by the predominantly fine-grained carbonates of
the Esfandiar Limestone Formation, pass eastward into slope to basin sediments of the Qal'eh Dokhtar Limestone Formation (platform-derived
allochthonites, microbialites, and peri-platform muds). Towards the west, they interfinger with bedded limestones and marlstones
(Kamar-e-Mehdi Formation), which were deposited in an extensive shelf lagoon. In a N−S direction, the Esfandiar Platform can
be traced for about 170 km, in an E-W direction, the platform extended for at least 35–40 km. The width of the eastern slope
of the platform is estimated at 10–15 km, the width of the western shelf lagoon varied considerably (>20–80 km). During the
Late Callovian to Middle Oxfordian, the Esfandiar Platform flourished under arid climatic conditions and supplied the slope
and basinal areas with large amounts of carbonates (suspended peri-platform muds and gravitational sediments). Export pulses
of platform material, e.g. ooids and aggregate grains, into the slope and basinal system are interpreted as highstand shedding
related to relative sealevel variations. The high-productivity phase was terminated in the Late Oxfordian when the eastern
platform areas drowned and homogeneous deep water marls of the Upper Oxfordian to Kimmeridgian Korond Formation onlapped both
the Qal'eh Dokhtar Limestone Formation and the drowned Esfandiar Limestone Formation. Tectonic instability, probably caused
by faulting at the margins of the Tabas Block in connection with rotational movements of the east-central Iranian block assemblage,
was responsible for the partial drowning of the eastern platform areas. In some areas, relicts of the platform persisted to
produce shallow-water sediments into the Kimmeridgian. 相似文献
36.
Summary Early Silurian reef reconstruction on the Yangtze Platform, in the northern part of the South China Block, is preceded by
a combination of regional and global processes. During most of Ashgill time (Late Ordovician), the area was dominated by Wufeng
Formation deep water graptolitic black shales. Reefs largely disappeard in the middle of the Ashgill Stage, from the northwestern
margin of Cathaysian Land (southeastern South China Block), in advance of the Late Ordovician glaciation and mass extinction,
due to regional sea-level changes and regional uplift, unrelated to the mass extinction itselt. Late Ordovician microbial
mudmound occurrence is also found in the western margin of the Yangtze Platform, its age corresponding to theDicellograptus complexus graptolite biozone of pre-extinction time. On the Yangtze Platform, a thin, non-reef-bearing carbonate, the Kuanyinchiao
Formation (=Nancheng Formation in some sites), thickness generally no more than 1m, occurs near several landmasses as a result
of Hirnantian regression. Reappearance of the earliest Silurian carbonates consisting of rare skeletal lenses in the upper
part of Lungmachi Formation, are correlated to theacensus graptolite biozone, early Rhuddanian of Shiqian, northeastern Guizhou, near Qianzhong Land. Carbonate sediments gradually
developed into beds rich in brachiopods and crinoids in the lower part of Xiangshuyuan Formation, middle Rhuddanian. In the
middle part of Xiangshuyan Formation, biostromes, containing abundant and high diversity benthic faunas such as corals, crinoids
and brachiopods, show beginnings of reconstruction of reef facies. Substantial reef recovery occurred in the upper part of
Xiangshuyuan Formation, lower Aeronian, as small patch reefs and biostromes. During the late Aeronian, carbonate sediments,
especially reefs and reef-related facies, expanded on the upper Yangtze Platform, and radiation of reefs occurred in Ningqiang
Formation, upper Telychian. The long period of reef recovery, taking several million years, remains difficult to explain,
because redistribution of any refugia faunas would be expected to take place soon after the extinction. Reefs and reef-related
facies subsequently declined after Telychian time due to regional uplift of the major portion of the Yangtze Platform. Carbonate
facies are therefore uncommon in South China during the rest of Silurian time. 相似文献
37.
东北虎雌性生殖系统的组织学 总被引:3,自引:1,他引:2
对10月份意外死亡的2例东北虎(Panthera tigris altaica)雌性生殖系统进行了组织学研究。卵巢基质中分布着一定数量的有腔卵泡及闭锁卵泡。间质腺不发达,在闭锁卵泡上皮样细胞增殖,形成一定量的间质腺细胞。输卵管漏半斗部至峡部黏膜上皮由柱状逐渐转化炎立方,黏膜形成许多皱褶,皱褶以漏斗部和壶腹部最多,子宫内膜上皮为单层立方上皮。6岁个体子宫腺上皮为单层柱状上皮;2岁个体在子宫角处的子宫腺上皮为单层柱状上皮,在子宫体外多为单层立方上皮,子宫腺密度从卵巢端到子宫体端呈阶梯下降,阴道黏膜上皮大多为2-3层的复层扁平上皮。 相似文献
38.
39.
《Biological reviews of the Cambridge Philosophical Society》2018,93(3):1478-1498
Animals that occupy temperate and polar regions have specialized traits that help them survive in harsh, highly seasonal environments. One particularly important adaptation is seasonal coat colour (SCC) moulting. Over 20 species of birds and mammals distributed across the northern hemisphere undergo complete, biannual colour change from brown in the summer to completely white in the winter. But as climate change decreases duration of snow cover, seasonally winter white species (including the snowshoe hare Lepus americanus, Arctic fox Vulpes lagopus and willow ptarmigan Lagopus lagopus) become highly contrasted against dark snowless backgrounds. The negative consequences of camouflage mismatch and adaptive potential is of high interest for conservation. Here we provide the first comprehensive review across birds and mammals of the adaptive value and mechanisms underpinning SCC moulting. We found that across species, the main function of SCC moults is seasonal camouflage against snow, and photoperiod is the main driver of the moult phenology. Next, although many underlying mechanisms remain unclear, mammalian species share similarities in some aspects of hair growth, neuroendocrine control, and the effects of intrinsic and extrinsic factors on moult phenology. The underlying basis of SCC moults in birds is less understood and differs from mammals in several aspects. Lastly, our synthesis suggests that due to limited plasticity in SCC moulting, evolutionary adaptation will be necessary to mediate future camouflage mismatch and a detailed understanding of the SCC moulting will be needed to manage populations effectively under climate change. 相似文献
40.
Summary The Vendian-Cambrian interval on the Siberian Platform contains thick carbonate and evaporite sequences formed in extensive
shallow-water basins. The carbonate sequences are characterized by a cyclic composition. Finegrained dolomites, undulated
algal dolomites, flat pebble conglomerates, storm breccias and solution-collapse breccias form the base of each cycle. These
rocks are characterized by an increased clay content which can be high enough to form argillites. Short sedimentation breaks
reflected by mudcracks or silicification horizons are present as well as small cross-bedded tidal channels. Peloidal grainstones
with algal overgrowth dominate in the central parts of the cycles. These members are often recrystallized and dolomitized.
Micritic dolomites, undulous laminated dolomites, storm breccias and columnar stromatolites with abundant mud cracks form
the upper members of the cycles. These sequences are free of clay but contain abundant anhydrite crystals and nodules. In
the uppermost parts of some cycles massive layered anhydrite beds are present. The cycles vary in thickness, but usually they
are between 15 and 20 m thick.
The lower cycle member documents extreme shallow-water deposits. They formed in tidal and partially also supratidal zones
not far from the mainland, from where fine clayey material was washed in. These parts of the sequence reflect a slow transgression.
The central member of a cycle was deposited during the maximal transgression in a shallow basin with normal salinity and rather
active hydrodynamics.
Sedimentation of the upper part of the cycles reflects a regression stage (tidal and especially sabkha environments). The
final layered anhydrite beds formed most probably in relict lakes on the sabkha plain. During sea-level falls some sequences
of the central parts of the cycles were subaerially exposed and underwent partial dolomitization.
The Vendian-Cambrian sabkhas are partly comparable with their recent counterparts. 相似文献