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291.
292.
AMANDA L. ROBERTSON YADVINDER MALHI FILIO FARFAN‐AMEZQUITA LUIZ EDUARDO O. C. ARAGO JAVIER EDUARDO SILVA ESPEJO MATTHEW A. ROBERTSON 《Global Change Biology》2010,16(12):3193-3204
Autotrophic respiration involves the use of fixed carbon by plants for their own metabolism, resulting in the release of carbon dioxide as a by‐product. Little is known of how autotrophic respiration components vary across environmental gradients, particularly in tropical ecosystems. Here, we present stem CO2 efflux data measured across an elevation transect spanning ca. 2800 m in the Peruvian Amazon and Andes. Forest plots from five elevations were studied: 194, 210, 1000, 1500, and 3025 m asl Stem CO2 efflux (Rs) values from each plot were extrapolated to the 1‐ha plot level. Mean Rs per unit stem surface area declined significantly with elevation, from 1.14±0.12 at 210 m elevation to 0.62±0.09 μmol C m−2 s−1 at 3025 m elevation. When adjusted for changing forest structure with elevation, this is equivalent to 6.45±1.12 Mg C ha−1 yr−1 at 210 m elevation to 2.94±0.19 Mg C ha−1 yr−1 at 3025 m elevation. We attempted to partition stem respiration into growth and maintenance respiration components for each site. Both growth and maintenance respiration rates per unit stem showed similar, moderately significant absolute declines with elevation, but the proportional decline in growth respiration rates was much greater. Stem area index (SAI) showed little trend along the transect, with declining tree stature at higher elevations being offset by an increased number of small trees. This trend in SAI is sensitive to changes in forest stature or size structure. In the context of rapid regional warming over the 21st century, such indirect, ecosystem‐level temperature responses are likely to be as important as the direct effects of temperature on maintenance respiration rates. 相似文献
293.
294.
The statistical analysis of mitochondrial DNA polymorphisms: chi 2 and the problem of small samples 总被引:10,自引:0,他引:10
Significance levels obtained from a chi 2 contingency test are suspect when
sample sizes are small. Traditionally this has meant that data must be
combined. However, such an approach may obscure heterogeneity and hence
potentially reduce the power of the statistical test. In this paper, we
present a Monte Carlo solution to this problem: by this method, no lumping
of data is required, and the accuracy of the estimate of alpha (i.e., a
type 1 error) depends only on the number of randomizations of the original
data set. We illustrate this technique with data from mtDNA studies, where
numerous genotypes are often observed and sample sizes are relatively
small.
相似文献
295.
VIKRAM PATEL MARIO MAJ ALAN J. FLISHER MARY J. DE SILVA MIRJA KOSCHORKE MARTIN PRINCE WPA Zonal Member Society Representatives 《World psychiatry》2010,9(3):169-176
The treatment gap for people with mental disorders exceeds 50% in all countries
of the world, approaching astonishingly high rates of 90% in the least resourced
countries. We report the findings of the first systematic survey of leaders
of psychiatry in nearly 60 countries on the strategies for reducing the treatment
gap. We sought to elicit the views of these representatives on the roles of
different human resources and health care settings in delivering care and
on the importance of a range of strategies to increase the coverage of evidence-based
treatments for priority mental disorders for each demographic stage (childhood,
adolescence, adulthood and old age). Our findings clearly indicate three strategies
for reducing the treatment gap: increasing the numbers of psychiatrists and
other mental health professionals; increasing the involvement of a range of
appropriately trained non-specialist providers; and the active involvement
of people affected by mental disorders. This is true for both high income
and low/middle income countries, though relatively of more importance in the
latter. We view this survey as a critically important first step in ascertaining
the position of psychiatrists, one of the most influential stakeholder communities
in global mental health, in addressing the global challenge of scaling up
mental health services to reduce the treatment gap. 相似文献
296.
Permanent Genetic Resources added to Molecular Ecology Resources Database 1 April 2010 - 31 May 2010
Molecular Ecology Resources Primer Development Consortium Andree K Axtner J Bagley MJ Barlow EJ Beebee TJ Bennetzen JL Bermingham E Boisselier-Dubayle MC Bozarth CA Brooks CP Brown RP Catanese G Cavers S Ceron-Souza I Chak ST Chan MN Charles-Dominique P Chen CY Chen JD Chinchilla L DA Silva D Dafreville S Daunt F Delatte H Dorge T Duncan N Durand JD Duvernell D Estep M Fan S Fattahi R Villela OF Fong Y Fréville H Funes V Gallardo-Escarate C Ganeshaiah KN Ghaffari MR Girod C Gomez-Moliner BJ 《Molecular ecology resources》2010,10(6):1098-1105
This article documents the addition of 396 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anthocidaris crassispina, Aphis glycines, Argyrosomus regius, Astrocaryum sciophilum, Dasypus novemcinctus, Delomys sublineatus, Dermatemys mawii, Fundulus heteroclitus, Homalaspis plana, Jumellea rossii, Khaya senegalensis, Mugil cephalus, Neoceratitis cyanescens, Phalacrocorax aristotelis, Phytophthora infestans, Piper cordulatum, Pterocarpus indicus, Rana dalmatina, Rosa pulverulenta, Saxifraga oppositifolia, Scomber colias, Semecarpus kathalekanensis, Stichopus monotuberculatus, Striga hermonthica, Tarentola boettgeri and Thermophis baileyi. These loci were cross-tested on the following species: Aphis gossypii, Sooretamys angouya, Euryoryzomys russatus, Fundulus notatus, Fundulus olivaceus, Fundulus catenatus, Fundulus majalis, Jumellea fragrans, Jumellea triquetra Jumellea recta, Jumellea stenophylla, Liza richardsonii, Piper marginatum, Piper aequale, Piper darienensis, Piper dilatatum, Rana temporaria, Rana iberica, Rana pyrenaica, Semecarpus anacardium, Semecarpus auriculata, Semecarpus travancorica, Spondias acuminata, Holigarna grahamii, Holigarna beddomii, Mangifera indica, Anacardium occidentale, Tarentola delalandii, Tarentola caboverdianus and Thermophis zhaoermii. 相似文献
297.
Analysis of Distribution of Root Length Density of Apple Trees on Different Dwarfing Rootstocks 总被引:3,自引:0,他引:3
This paper considers statistical analyses for comparing thedistribution of root length density (RLD) of apple trees underdifferent rootstocks and tree spacing. The source data includedRLD values (cm cm-3) measured by soil coring the root systemsof eight trees in each of two seasons. We formulated a regressionmodel which assumed the RLD dropped exponentially with soildepth, and this relationship varied with the radial distancefrom the tree. The model fitted to the log transformed meandata described the RLD distribution well. Young trees (5-year-old)of M.26 (semi-dwarf) and MM.106 (semi-vigourous) had a highermean RLD and showed a more layered vertical distribution, comparedwith trees of the dwarf Mark rootstock. Differences among rootstockswere not evident in older (9-year-old) trees. In general, youngroot systems were more bowl shaped, whereas older trees hada higher RLD further away from the tree trunk. RLD is a positiveand continuous variable except for the possibility of an excessof exact zeros. A generalized linear model with a Poisson-gammatype distribution allows modelling of individual RLD data withzeros contributing to parameter estimation. It does not, however,provide simplicity of biological interpretation. In this paperwe present a model that assumes the realization of RLD datais due to a Bernoulli and an exponential process. The fittingof the Bernoulli-exponential model by maximum likelihood isillustrated, and further generalization suggested.Copyright1999 Annals of Botany Company Malus domestica(Borkh.), Fuji, rootstock, root system, soil core sampling, Bernoulliexponential model. 相似文献
298.
CARLOS R. M. DA SILVA M. SOCORRO GONZÁLEZ-ELIZONDO ANDRÉ L. L. VANZELA 《Botanical journal of the Linnean Society. Linnean Society of London》2005,149(4):457-464
Eleocharis subarticulata is recorded as the third species of Cyperaceae with a reduced chromosome number ( n = 3), following reports on Rhynchospora tenuis ( n = 2) and Fimbristylis umbellaris ( n = 3). For Eleocharis, the numbers recorded to date vary from 2 n = 10 to 2 n = c. 196, with x = 5 as the possible basic number. The karyotype of E. subarticulata was studied using conventional staining (mitosis and meiosis), C-CMA3 /DAPI banding, and FISH with 45S rDNA and telomere probes. The chromosomes showed no primary constrictions, as expected in the holocentric chromosomes of Cyperaceae. The meiotic behaviour was abnormal, with a single multivalent ring of six chromosomes at metaphase I, resulting from multiple translocations. At anaphase I six chromatids migrated to each pole, evidencing the inverted meiosis, and these groups were also visible at metaphase II. The C-CMA3 /DAPI banding technique showed only four terminal GC-rich blocks. FISH with 45S rDNA probes revealed four terminal signals, probably associated with GC-rich blocks. The telomeric probe located terminal signals in all the chromosomes, besides a hybridization site in the middle of the large pair. The occurrence of ectopic telomeric sites has not been described previously for plants with holokinetic karyotypes and with reduced chromosome numbers. These data reinforce the hypothesis of the reduction in chromosome number by multiple translocations. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 457–464. 相似文献
299.
MÁRCIO R. VELOSO FRANCELINO ADRIANA DE LIMA MENDONÇA RUTH R. DO NASCIMENTO FERNANDO A. C. DE MENDONÇA EDLEIDE L. DA SILVA MARIA DO ROSÁRIO T. DE FREITAS CYRO R. CABRAL JR CARLOS EDUARDO DA SILVA JOSÉ H. S. RIBEIRO ANTÔNIO EUZÉBIO G. SANTANA 《Physiological Entomology》2008,33(1):37-42
Abstract. Ethological studies are conducted under laboratory conditions using workers of Atta sexdens sexdens and Atta opaciceps collected from field colonies to investigate the mechanisms involved in the alarm response and intra-specific recognition in leaf-cutting ants. Hexane extracts from the heads of gardeners and generalist workers elicit higher levels of alarm response in foragers from the same colony than do mandibular gland extracts from foragers and soldiers, indicating that gardeners, generalists and foragers are primarily responsible for the production of alarm pheromone. Foragers subjected to extracts from non-nestmates exhibit significantly greater alarm responses than are induced by similar extracts derived from nestmate workers, suggesting that the alarm pheromone may have a role in nestmate recognition. 相似文献
300.
PAULO SILVEIRA RÉ SCHUITEMAN JAAP JAN VERMEULEN ANA J. SOUSA HELENA SILVA JORGE PAIVA ED DE VOGEL 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(2):197-215
A checklist of the Orchidaceae of Timor is presented, with emphasis on the eastern half of the island (East Timor), based on historical herbarium collections and recent botanical explorations. This list comprises 38 genera with 66 species, including 15 new genera and 32 new species records for this island. Moreover, four new species are described: Bulbophyllum sundaicum , Habenaria ankylocentron , Habenaria cauda‐porcelli , and Pterostylis timorensis . Of these, we consider the finding of a new species of Pterostylis to be especially noteworthy, because this species seems to be more closely related to certain Australian members of the genus than to the Malesian ones, suggesting earlier contacts of Timor with Australia. Four new synonyms are proposed: Calanthe veratrifolia var. timorensis J.J.Sm. (C. triplicata), Habenaria cornuta Span. (H. giriensis), H. grandis Benth. ex Ridl. (Peristylus goodyeroides), and H. mutica Span. (H. elongata). The best represented genus is Habenaria, with 13 species, followed by Dendrobium with four, and Bulbophyllum with three. Because of insufficient or sterile material, it was not possible to identify, or describe as new, 20 different taxa. The conservation status of the ten endemic species, plus six possible new undescribed species and two non‐endemic, but threatened, species, was assessed using the World Conservation Union (IUCN) criteria, and categories of threat were proposed. Seven endemic species are considered to be Critically Endangered and two Endangered. One of the nonendemic species is considered to be Critically Endangered, and the other Endangered. The survival of some of these species might be less insecure if an effective application of Regulation project N.2000/19 on protected areas (UNTAET/REG/2000/19) was implemented and maintained, because most of these species were collected in areas considered for protection under this Regulation. Further studies are required, however, in order to complete our knowledge of the diversity and population dynamics of this interesting part of Timor's biodiversity. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 197–215. 相似文献