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991.
Molecular and structural basis of ESCRT-III recruitment to membranes during archaeal cell division 总被引:1,自引:0,他引:1
Highlights? A conserved protein, CdvA, recruits ESCRT-III to membranes during cell division ? Recruitment is mediated by a peptide-winged helix domain interaction ? We have determined the structure of this complex ? CdvA and a single ESCRT-III protein can drive membrane deformation in vitro 相似文献
992.
993.
994.
Schuster M Kilaru S Fink G Collemare J Roger Y Steinberg G 《Molecular biology of the cell》2011,22(19):3645-3657
The polarity of microtubules (MTs) determines the motors for intracellular motility, with kinesins moving to plus ends and dynein to minus ends. In elongated cells of Ustilago maydis, dynein is thought to move early endosomes (EEs) toward the septum (retrograde), whereas kinesin-3 transports them to the growing cell tip (anterograde). Occasionally, EEs run up to 90 μm in one direction. The underlying MT array consists of unipolar MTs at both cell ends and antipolar bundles in the middle region of the cell. Cytoplasmic MT-organizing centers, labeled with a γ-tubulin ring complex protein, are distributed along the antipolar MTs but are absent from the unipolar regions. Dynein colocalizes with EEs for 10-20 μm after they have left the cell tip. Inactivation of temperature-sensitive dynein abolishes EE motility within the unipolar MT array, whereas long-range motility is not impaired. In contrast, kinesin-3 is continuously present, and its inactivation stops long-range EE motility. This indicates that both motors participate in EE motility, with dynein transporting the organelles through the unipolar MT array near the cell ends, and kinesin-3 taking over at the beginning of the medial antipolar MT array. The cooperation of both motors mediates EE movements over the length of the entire cell. 相似文献
995.
Sally A. Keith Roger J.H. Herbert Paul A. Norton Stephen J. Hawkins Adrian C. Newton 《Diversity & distributions》2011,17(2):275-286
Aim Evidence indicates that species are responding to climate change through distributional range shifts that track suitable climatic conditions. We aim to elucidate the role of meso‐scale dispersal barriers in climate‐tracking responses. Location South coast of England (the English Channel). Methods Historical distributional data of four intertidal invertebrate species were logistically regressed against sea surface temperature (SST) to determine a climate envelope. This envelope was used to estimate the expected climate‐tracking response since 1990 along the coast, which was compared with observed range expansions. A hydrodynamic modelling approach was used to identify dispersal barriers and explore disparities between expected and observed climate tracking. Results Range shifts detected by field survey over the past 20 years were less than those predicted by the changes that have occurred in SST. Hydrodynamic model simulations indicated that physical barriers produced by complex tidal currents have variably restricted dispersal of pelagic larvae amongst the four species. Main conclusions We provide the first evidence that meso‐scale hydrodynamic barriers have limited climate‐induced range shifts and demonstrate that life history traits affect the ability of species to overcome such barriers. This suggests that current forecasts may be flawed, both by overestimating range shifts and by underestimating climatic tolerances of species. This has implications for our understanding of climate change impacts on global biodiversity. 相似文献
996.
Mark McNeill Craig Phillips Sandra Young Farhat Shah Lee Aalders Nigel Bell Emily Gerard Roger Littlejohn 《Biological invasions》2011,13(12):2799-2815
The potential for transported soil to harbour and spread nonindigenous species (NIS) is widely recognised and many National
Plant Protection Organisations (NPPOs) restrict or prohibit its movement. However, surprisingly few studies have surveyed
soil while it is in transit to provide direct support for its role in accidental introductions of NIS. Moreover, there are
few border interception records for soil organisms because they are neither easily detected nor routinely isolated and identified.
Better data would improve evaluations of risks from soil transported via different pathways, enable targeting of management
resources at the riskiest pathways, and support development of new risk management methods. We surveyed organisms present
in soil that had been removed from footwear being carried in the baggage of international aircraft passengers arriving in
New Zealand and recorded high incidences, counts and diversities of viable bacteria, fungi, nematodes and seeds, as well as
several live arthropods. These included taxa that have not been recorded in New Zealand and were therefore almost certainly
nonindigenous to this country. In each gram of soil, there was an estimated 52–84% incidence of genera that contain species
regulated by New Zealand’s NPPO, which suggests many were potentially harmful. Variation in the incidences and counts of soil
organisms with sample weight, footwear type and season at the port of departure indicated it may be possible to develop methods
for targeting management resources at the riskiest footwear. Comparisons with previously published data supported the hypothesis
that survival of soil organisms is greater when they are transported in protected (e.g. in luggage) rather than unprotected
environments (e.g. external surfaces of sea containers); this offers opportunities to develop methods for targeting management
resources at the most hazardous soil pathways. 相似文献
997.
The Mss4 (mammalian suppressor of yeast Sec4) is an evolutionarily highly conserved protein and is expressed in all mammalian tissues. Although its precise biological function is still elusive, it has been shown to associate with a subset of secretory Rab proteins (Rab1b, Rab3a, Rab8a, Rab10) and to possess a rather low guanine nucleotide exchange factor (GEF) activity towards them in vitro (Rab1, Rab3a and Rab8a). By screening a human placenta cDNA library with Mss4 as bait, we identified several Rab GTPases (Rab12, Rab13 and Rab18) as novel Mss4-binding Rab proteins. Only exocytic but no endocytic Rab GTPases were found in our search. The binding of Mss4 to Rab proteins was confirmed by direct yeast two-hybrid interaction, by co-immunoprecipitation from lysates of mammalian cells, by immunofluorescence colocalisation as well as by direct in vitro binding studies. Analysis of Mss4 catalytic activity towards different Rab substrates confirmed that it is a somewhat inefficient GEF. These data, together with our mutational analysis of Mss4-Rab binding capacity, support the already proposed idea that Mss4 functions rather as a chaperone for exocytic Rab GTPases than as a GEF. 相似文献
998.
Anderson OR 《Protist》2011,162(5):679-690
999.
Marie Billaud Diana Dahan Roger Marthan Jean-Pierre Savineau Christelle Guibert 《Respiratory research》2011,12(1):30
Background
Pulmonary hypertension (PH) is characterized by arterial vascular remodelling and alteration in vascular reactivity. Since gap junctions are formed with proteins named connexins (Cx) and contribute to vasoreactivity, we investigated both expression and role of Cx in the pulmonary arterial vasoreactivity in two rat models of PH.Methods
Intrapulmonary arteries (IPA) were isolated from normoxic rats (N), rats exposed to chronic hypoxia (CH) or treated with monocrotaline (MCT). RT-PCR, Western Blot and immunofluorescent labelling were used to study the Cx expression. The role of Cx in arterial reactivity was assessed by using isometric contraction and specific gap junction blockers. Contractile responses were induced by agonists already known to be involved in PH, namely serotonin, endothelin-1 and phenylephrine.Results
Cx 37, 40 and 43 were expressed in all rat models and Cx43 was increased in CH rats. In IPA from N rats only, the contraction to serotonin was decreased after treatment with 37-43Gap27, a specific Cx-mimetic peptide blocker of Cx 37 and 43. The contraction to endothelin-1 was unchanged after incubation with 40Gap27 (a specific blocker of Cx 40) or 37-43Gap27 in N, CH and MCT rats. In contrast, the contraction to phenylephrine was decreased by 40Gap27 or 37-43Gap27 in CH and MCT rats. Moreover, the contractile sensitivity to high potassium solutions was increased in CH rats and this hypersensitivity was reversed following 37-43Gap27 incubation.Conclusion
Altogether, Cx 37, 40 and 43 are differently expressed and involved in the vasoreactivity to various stimuli in IPA from different rat models. These data may help to understand alterations of pulmonary arterial reactivity observed in PH and to improve the development of innovative therapies according to PH aetiology. 相似文献1000.
The conservation of wildlife populations living adjacent to roads is gaining international recognition as a worldwide concern.
Populations living in road-impacted environments are influenced by spatial parameters including the amount and arrangement
of suitable habitat. Similarly, heterogeneity in threatening processes can act at a variety of spatial scales and be crucial
in affecting population persistence. Common wombats (Vombatus ursinus) are considered both widespread and abundant throughout their eastern Australian continental distribution. They nevertheless
face many threats, primarily human induced. As well as impacts from disease and predation by introduced species, high roadside
fatality rates on many rural roads are frequently reported. We parameterized a model for common wombat population viability
analysis within a 750-km2 area of the northwestern corner of Kosciuszko National Park in New South Wales, Australia, and tested its sensitivity to
changes in the values of basic parameters. We then assessed the relative efficiency of various mitigation measures by examining
the combined impact from roads, disease and predation on wombat subpopulation persistence in the area. We constructed a stage-structured
and spatially explicit model incorporating estimates of survival and fecundity parameters for each of the identified subpopulations
using RAMAS GIS. Estimates of current threatening processes suggest mitigating road-kill is the most effective management
solution. Results highlight the importance of recognizing the interplay between various threats and how their combination
has the capacity to drive local depletion events. 相似文献