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121.
122.
Michaël M. Vork Jan F. C. Glatz Ger J. van der Vusse 《Molecular and cellular biochemistry》1993,123(1-2):175-184
To obtain insight into the relation between the release of heart-type fatty acid-binding protein (H-FABPc) and of long-chain fatty acids (FA) from injured cardiac tissue, rat hearts were Langendorff perfused according to the following scheme: 30 min normoxia, 60 min ischemia, 30 min reperfusion, 10 min Ca2+ free perfusion and finally 10 min Ca2+ repletion. During this protocol right ventricular (Q
rv
) and interstitial effluent samples (Q
i
) were collected at regular intervals. During reperfusion a total of 0.8±0.1 nmol H-FABPc but no FA were detected in the effluents. However, during Ca2+ readmission, 45±4 nmol H-FABPc (80–90% of total tissue content) was released with an initial (first 3 min) simultaneous release of FA (FA/H-FABPc ratio 0.90±0.07 mol/mol). Thereafter, FA release continued at 10–15 nmol per min mainly inQ
rv
while the rate of H-FABPc release decreased. During Ca2+ repletion, tissue FA content raised rapidly from 168±20 to 1918±107 nmol/g dry weight. These findings suggest that after severe cardiac damage initially FA is released bound to H-FABPc, whereas further FA release occurs in a non-protein bound manner. 相似文献
123.
A hierarchy is an abstract organizational model of inter-level relationships among entities. When isomorphic with nature, hierarchies are useful for organizing and manipulating our knowledge. Hierarchies have been used in biological systematics to represent several distinct, but interrelated, facets of the evolution of life with different organizational properties, and these distinctions have been confused by the rubric 'the hierarchy of life'. Evolution, as descent with modification, is inherently dualistic. The organizational structure of a hierarchy can be used to represent dualistic properties as inter-level relationships. Cladistics is monistic, with a singular focus on patterns of descent. Descent has conceptual priority over modification, but the organizational relationship is not exclusive. 'Cladistic classification' is an oxymoron because cladistics lacks the class concepts needed to construct a classification, a point recognized by those who suggest abandoning Linnaean classification in favour of a newly devised monophyletic systematization. Cladistic analysis of descent can be supplemented with an analysis of modification that provides the class concepts needed to construct an evolutionary/phylogenetic classification. When a strong monophyletic pattern of modification is detected (in addition to its monophyletic pattern of descent), the criterion of subsequent modification provides the basis for formally recognizing a certain monophyletic group at a given rank, as opposed to a group that is one node more inclusive or one node less. The criterion of subsequent modification also permits detection of strong paraphyletic patterns of modification, when they exist. By setting standards of evidence needed to recognize paraphyletic groups, one concomitandy strengthens the basis for formally recognizing selective monophyletic groups. 相似文献
124.
Guy?JosensEmail author Abraham?Bij?de?Vaate Philippe?Usseglio-Polatera Roger?Cammaerts Frédéric?Chérot Frédéric?Grisez Pierre?Verboonen Jean-Pierre?Vanden?Bossche 《Hydrobiologia》2005,542(1):203-220
Samples issued from intensive sampling in the Netherlands (1992–2001) and from extensive sampling carried out in the context
of international campaigns (1998, 2000 and 2001) were revisited. Additional samples from artificial substrates (1992–2003)
and other techniques (various periods) were analysed. The combined data provide a global and dynamic view on the Peracarida
community of the River Meuse, with the focus on the Amphipoda. Among the recent exotic species found, Crangonyx pseudogracilisis regressing, Dikerogammarus haemobaphesis restricted to the Condroz course of the river, Gammarus tigrinusis restricted to the lowlands and seems to regress, Jaera istriis restricted to the ‘tidal’ Meuse, Chelicorophium curvispinumis still migrating upstream into the Lorraine course without any strong impact on the other amphipod species. After a rapid
expansion Dikerogammarus villosushas continued its upstream invasion between 1998 and 2002 at a rate of 30–40 km per year, but no further progression was noticed
in 2003. Locally and temporarily the native species (Gammarus fossarum and G. pulex) and naturalized species (G. roeseliand Echinogammarus berilloni)mayhave been excluded by the most recent invaders (mainly D. villosus), but none of the native and naturalized species has disappeared completely. Therefore, the number of amphipod species found
in the River Meuse has increased. Moreover, the native and naturalized species keep on dominating the tributaries from which
the recent invaders seem to be excluded. A changing Peracarida community structure is observed along the course of the River
Meuse: four native or naturalized species inhabit the upstream (Lorraine) course, three invasive species dominate in the middle
reach (Ardenne-Condroz zone), one exotic species is housed in the Border Meuse and three or four invasive species dominate
the assemblages in the lowlands. 相似文献
125.
Intermittent high altitude hypoxia protects the heart against lethal Ca2+ overload injury 总被引:2,自引:0,他引:2
Adaptation to intermittent high altitude (IHA) hypoxia can protect the heart against ischemia-reperfusion injury. In view of the fact that both Ca2+ paradox and ischemia-reperfusion injury are associated with the intracellular Ca2+ overload, we tested the hypothesis that IHA hypoxia may protect hearts against Ca2+ paradox-induced lethal injury if its cardioprotection bases on preventing the development of intracellular Ca2+ overload. Langendorff-perfused hearts from normoxic and IHA hypoxic rats were subjected to Ca2+ paradox (5 min of Ca2+ depletion followed by 30 min of Ca2+ repletion) and the functional, biochemical and pathological changes were investigated. The Ca2+ paradox incapacitated the contractility of the normoxic hearts, whereas the IHA hypoxic hearts significantly preserved contractile activity. Furthermore, the normoxic hearts subjected to Ca2+ paradox exhibited a marked reduction in coronary flow, increase in lactate dehydrogenase release, and severe myocyte damage. In contrast, these changes were significantly prevented in IHA hypoxic hearts. We, then, tested and confirmed our hypothesis that the protective mechanisms are mediated by mitochondria ATP-sensitive potassium channels (mitoKATP) and Ca2+/calmodulin-dependent protein kinase II (CaMKII), as the protective effect of IHA hypoxia was abolished by 5-hydroxydecanoate, a selective mitoKATP blocker, and significantly attenuated by KN-93, a CaMKII inhibitor. In conclusion, our studies offer for the first time that IHA hypoxia confers cardioprotection against the lethal injury of Ca2+ paradox and give biochemical evidence for the protective mechanism of IHA hypoxia. We propose that researches in this area may lead a preventive regimen against myocardial injury associated with Ca2+ overload. 相似文献
126.
It takes one to know one: Similarity to resident alien species increases establishment success of new invaders 下载免费PDF全文
Christine S. Sheppard Marta Carboni Franz Essl Hanno Seebens DivGrass Consortium Wilfried Thuiller 《Diversity & distributions》2018,24(5):680-691
Aim
Darwin's naturalization hypothesis states that dissimilarity to native species may benefit alien species establishment due to empty niches and reduced competition. We here add a new dimension to large‐scale tests of community invasibility, investigating the role that previously established alien species play in facilitating or hindering new invasions in plant communities.Location
Permanent grasslands across France (including mainland and Corsica), as a receding ecosystem of great conservation importance.Methods
Focusing on 121 alien plant species occurring in 7,215 vegetation plots, we quantified biotic similarity between new invaders and resident alien species (i.e., alien species with longer residence times) based on phylogenetic and trait distances. Additionally, we calculated distances to native species for each alien species and plot. Using multispecies distribution models, we analysed the influence of these biotic similarity measures and additional covariates on establishment success (presence/absence) of new invaders.Results
We found that biotic similarity to resident alien species consistently increased establishment success of more recently introduced species. Phylogenetic relatedness to previous invaders had an equally strong positive effect as relatedness to native species. Conversely, trait similarity to natives hindered alien establishment as predicted by Darwin's naturalization hypothesis. These results highlight that various mechanisms may act simultaneously to determine alien establishment success.Main conclusions
Our results suggest that, with greater similarity among alien species, invasion success increases. Such a pattern may arise either due to actual facilitation among invaders or as a result of weaker competitive interactions among invaders than between native and alien species, leading to an indirect facilitative effect. Alternatively, recent environmental changes (e.g., eutrophication, climate change) may have added new environmental filters. Determining how initial invasions might pave the road for subsequent invasions is crucial for effective multispecies management decisions and contributes a new aspect to our understanding of community assembly.127.
Limited dispersal prevents Quercus rubra invasion in a 14‐species common garden experiment 下载免费PDF全文
Andrzej M. Jagodziński Marcin K. Dyderski Paweł Horodecki Katarzyna Rawlik 《Diversity & distributions》2018,24(3):403-414
Aim
Information about the importance of propagule pressure and habitat invasibility in invasion success of dispersal‐limited species is scarce. We aimed to assess invasiveness of Quercus rubra within stands of 14 tree species, and the effects of distance from propagule source on invasion success, to highlight limiting factors for further application in nature conservation.Location
Siemianice Experimental Forest—a common garden forest experiment with 14 tree species, western Poland.Methods
We investigated aboveground biomass, leaf area index and density of Q. rubra natural regeneration within 53 experimental plots, as well as distance from the seed source. We also analysed light availability changes between 2005 and 2015 on plots of each tree species. We used multiple linear regression and variable importance to quantify the effect of each factor.Results
All factors tested influenced ecological success of Q. rubra. Invasion success decreased with increasing distance from the seed source and decreasing light availability and was higher within stands of pioneer tree species. Leaf area index depended mostly on tree stand species, density depended on distance from the propagule source and biomass depended on both. Light availability explained 7.2%–30.2% of the variance; tree species—from 36.1% to 57.4%; and distance from the propagule source—from 12.4% to 56.7%.Main conclusions
Tree stand species, light availability and distance from the propagule source influence ecological success of invasive Q. rubra, displaying their importance for spread of this species. These factors are controllable in forest/conservation management and may be used to prevent Q. rubra invasion. Planting late‐successional tree species that cast dense shade, maintaining canopy closure and removing fruiting trees from surrounding more invasible stands may prevent Q. rubra invasion.128.
Jessica L. Tracy Conor M. Steckler Daniel Randles Eric Mercadante 《Evolution and human behavior》2018,39(5):520-528
Models of human altruism suggest that decisions to help are influenced by assessments of both potential recipients' need state and their competence, as high need increases the value of gifts received, and competent recipients can most effectively use and repay gifts. Need and competence are often inversely related, however, raising the question of how altruists weigh these competing sources of information. We examined the impact of a nonverbal display (expansive posture) that, by signaling high status, simultaneously cues both low need and high competence, on actual altruistic behaviors: donations of financial aid to needy individuals. Across three studies using ecologically valid data drawn from a micro-lending charity website, men who displayed expansive posture while requesting aid faced a substantial reduction in the amount of aid they received; this effect held controlling for a range of relevant covariates. These findings demonstrate that: (a) altruists bias their giving toward those in greater need rather those who may be more competent, and (b) subtle nonverbal cues of status influence altruistic decision-making. 相似文献
129.
Peter Hammerstein 《Journal of mathematical biology》1996,34(5-6):511-532
This paper investigates the problem of how to conceive a robust theory of phenotypic adaptation in non-trivial models of
evolutionary biology. A particular effort is made to develop a foundation of this theory in the context of n-locus population genetics. Therefore, the evolution of phenotypic traits is considered that are coded for by more than one
gene. The potential for epistatic gene interactions is not a priori excluded. Furthermore, emphasis is laid on the intricacies
of frequency-dependent selection. It is first discussed how strongly the scope for phenotypic adaptation is restricted by
the complex nature of ‘reproduction mechanics’ in sexually reproducing diploid populations. This discussion shows that one
can easily lose the traces of Darwinism in n-locus models of population genetics. In order to retrieve these traces, the outline of a new theory is given that I call
‘streetcar theory of evolution’. This theory is based on the same models that geneticists have used in order to demonstrate
substantial problems with the ‘adaptationist programme’. However, these models are now analyzed differently by including thoughts
about the evolutionary removal of genetic constraints. This requires consideration of a sufficiently wide range of potential
mutant alleles and careful examination of what to consider as a stable state of the evolutionary process. A particular notion
of stability is introduced in order to describe population states that are phenotypically stable against the effects of all
mutant alleles that are to be expected in the long-run. Surprisingly, a long-term stable state can be characterized at the
phenotypic level as a fitness maximum, a Nash equilibrium or an ESS. The paper presents these mathematical results and discusses
– at unusual length for a mathematical journal – their fundamental role in our current understanding of evolution.
Received 22 April 1994; received in revised form 10 July 1995 相似文献
130.
Abstract. Heracleum mantegazzianum, a tall forb from the western Caucasus invaded several different habitats in the Czech Republic. The relation between invasion success and type of recipient habitat was studied in the Slavkovskù les hilly ridge, Czech Republic. The vegetation of 14 habitat types occurring in an area of ca. 25 km2 was analysed using phytosociological relevés, and the invasion success of Heracleum (in terms of number of localities, area covered and proportion of available area occupied) was recorded separately in each of them. Site conditions were expressed indirectly using Ellenberg indicator values. The hypothesis tested was that Heracleum spreads in the majority of vegetation types regardless of the properties of the recipient vegetation. Community invasibility appeared to be affected by site conditions and the composition of the recipient vegetation. The species is not found in acidic habitats. Disturbed habitats with good possibilities of dispersal for Heracleum seeds are more easily invaded. Communities with a higher proportion of phanerophytes and of species with CS (Competitive/Stresstolerating) strategy were more resistant to invasion. The invasion success was bigger in sites with increased possibilities of spread for Heracleum diaspores. Communities invaded by Heracleum had a lower species diversity and a higher indicator value for nitrogen than not-invaded stands. It appears that species contributing to community resistance against invasion of Heracleum, or capable of persisting in Heracleum-invaded stands, have similar ecological requirements but a different life strategy to the invader. 相似文献