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101.
Thinking and managing outside the box: coalescing connectivity networks to build region-wide resilience in coral reef ecosystems 总被引:4,自引:4,他引:0
R. S. Steneck C. B. Paris S. N. Arnold M. C. Ablan-Lagman A. C. Alcala M. J. Butler L. J. McCook G. R. Russ P. F. Sale 《Coral reefs (Online)》2009,28(2):367-378
As the science of connectivity evolves, so too must the management of coral reefs. It is now clear that the spatial scale
of disturbances to coral reef ecosystems is larger and the scale of larval connectivity is smaller than previously thought.
This poses a challenge to the current focus of coral reef management, which often centers on the establishment of no-take
reserves (NTRs) that in practice are often too small, scattered, or have low stakeholder compliance. Fished species are generally
larger and more abundant in protected reserves, where their reproductive potential is often greater, yet documented demographic
benefits of these reproductive gains outside reserves are modest at best. Small reproductive populations and limited dispersal
of larvae play a role, as does the diminished receptivity to settling larvae of degraded habitats that can limit recruitment
by more than 50%. For “demographic connectivity” to contribute to the resilience of coral reefs, it must function beyond the
box of no-take reserves. Specifically, it must improve nursery habitats on or near reefs and enhance the reproductive output
of ecologically important species throughout coral reef ecosystems. Special protection of ecologically important species (e.g.,
some herbivores in the Caribbean) and size-regulated fisheries that capitalize on the benefits of NTRs and maintain critical
ecological functions are examples of measures that coalesce marine reserve effects and improve the resilience of coral reef
ecosystems. Important too is the necessity of local involvement in the management process so that social costs and benefits
are properly assessed, compliance increased and success stories accrued. 相似文献
102.
Connectivity and resilience of coral reef metapopulations in marine protected areas: matching empirical efforts to predictive needs 总被引:2,自引:1,他引:1
Botsford LW White JW Coffroth MA Paris CB Planes S Shearer TL Thorrold SR Jones GP 《Coral reefs (Online)》2009,28(2):327-337
Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population
models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing
of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal
is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix
containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged
among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale
of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal
influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical
and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report
current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local
retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of
biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their
sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress
in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers
will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population
modelers need to track and assimilate evolving empirical results. 相似文献
103.
Mesoderm migration is a well studied morphogenetic movement that takes place during Xenopus gastrulation. The study of mesoderm migration and other morphogenetic movements has been primarily based on in vitro assays due to the inability to image deep tissue movements in the opaque embryo. We are the first to report the use of Near Infra Red Quantum Dots (NIR QD’s) to image mesoderm migration in vivo with single cell resolution and provide quantitative in vivo data regarding migration rates. In addition we use QD’s to address the function of the focal adhesion kinase (FAK) in this movement. Inhibition of FAK blocks mesoderm spreading and migration both in vitro and in vivo without affecting convergent extension highlighting the molecular differences between the two movements. These results provide new insights about the role of FAK and of focal adhesions during gastrulation and provide a new tool for the study of morphogenesis in vivo. 相似文献
104.
We describe an intein based method to site-specifically conjugate Quantum Dots (QDs) to target proteins in vivo. This approach allows the covalent conjugation of any nanostructure and/or nanodevice to any protein and thus the targeting
of such material to any intracellular compartment or signalling complex within the cells of the developing embryo. We genetically
fused a pleckstrin-homology (PH) domain with the N-terminus half of a split intein (IN). The C-terminus half (IC) of the intein was conjugated to QDs in vitro. IC-QD's and RNA encoding PH-IN were microinjected into Xenopus embryos. In vivo intein-splicing resulted in fully functional QD-PH conjugates that could be monitored in real time within live embryos. Use
of Near Infra Red (NIR)-emitting QDs allowed monitoring of QD-conjugates within the embryo at depths where EGFP is undetectable
demonstrating the advantages of QD's for this type of experiment. In conclusion, we have developed a novel in vivo methodology for the site-specific conjugation of QD's and other artificial structures to target proteins in different intracellular
compartments and signaling complexes. 相似文献
105.
Warshakoon NC Sheville J Bhatt RT Ji W Mendez-Andino JL Meyers KM Kim N Wos JA Mitchell C Paris JL Pinney BB Reizes O Hu XE 《Bioorganic & medicinal chemistry letters》2006,16(19):5207-5211
A novel series of substituted quinoline analogs were designed and synthesized as potent and selective melanin concentrating hormone (MCH) antagonists. These analogs show potent (nM) activity (12a-k) with a moderate selectivity. Conversely, the conformationally constrained thienopyrimidinone analogs (18a-g) showed improved activity in MCH-1R and selectivity over 5HT2C. 相似文献
106.
107.
108.
Amaya MF Watts AG Damager I Wehenkel A Nguyen T Buschiazzo A Paris G Frasch AC Withers SG Alzari PM 《Structure (London, England : 1993)》2004,12(5):775-784
Sialidases are a superfamily of sialic-acid-releasing enzymes that are of significant interest due to their implication as virulence factors in the pathogenesis of a number of diseases. However, extensive studies of viral and microbial sialidases have failed to provide a comprehensive picture of their mechanistic properties, in part because the structures of competent enzyme-substrate complexes and reaction intermediates have never been described. Here we report these structures for the Trypanosoma cruzi trans-sialidase (TcTS), showing that catalysis by sialidases occurs via a similar mechanism to that of other retaining glycosidases, but with some intriguing differences that may have evolved in response to the substrate structure. 相似文献
109.
Background and Aims
Thousands of floor mosaics were produced in lands across the Roman and Byzantine empires. Some mosaics contain depictions of agricultural produce, potentially providing useful information concerning the contemporary presence and popularity of crop plants in a particular geographical region. Hundreds of floor mosaics produced in Israel during the Byzantine period have survived. The objective of the present work was to search these mosaics for Cucurbitaceae in order to obtain a more complete picture of cucurbit crop history in the eastern Mediterranean region.Results and Conclusions
Twenty-three mosaics dating from 350–600 ce were found that had images positively identifiable as cucurbits. The morphological diversity of the cucurbit fruits in the mosaics of Israel is greater than that appearing in mosaics from any other Roman or Byzantine provincial area. The depicted fruits vary in shape from oblate to extremely long, and some are furrowed, others are striped and others lack definite markings. The cucurbit taxa depicted in the mosaics are Cucumis melo (melon), Citrullus lanatus (watermelon), Luffa aegyptiaca (sponge gourd) and Lagenaria siceraria (bottle gourd). Cucumis melo is the most frequently found taxon in the mosaics and is represented by round dessert melons and long snake melons. Fruits of at least two cultivars of snake melons and of watermelons are represented. To our knowledge, images of sponge gourds have not been found in Roman and Byzantine mosaics elsewhere. Indeed, the mosaics of Israel contain what are probably the oldest depictions of Luffa aegyptiaca in Mediterranean lands. Sponge gourds are depicted often, in 11 of the mosaics at eight localities, and the images include both mature fruits, which are useful for cleaning and washing, and immature fruits, which are edible. Only one mosaic has images positively identifiable as of bottle gourds, and these were round–pyriform and probably used as vessels. 相似文献110.
Sandro Huenchuguala Patricia Mu?oz Patricio Zavala Mónica Villa Carlos Cuevas Ulises Ahumada Rebecca Graumann Beston F Nore Eduardo Couve Bengt Mannervik Irmgard Paris Juan Segura-Aguilar 《Autophagy》2014,10(4):618-630
U373MG cells constitutively express glutathione S-transferase mu 2 (GSTM2) and exhibit 3H-dopamine uptake, which is inhibited by 2 µM of nomifensine and 15 µM of estradiol. We generated a stable cell line (U373MGsiGST6) expressing an siRNA against GSTM2 that resulted in low GSTM2 expression (26% of wild-type U373MG cells). A significant increase in cell death was observed when U373MGsiGST6 cells were incubated with 50 µM purified aminochrome (18-fold increase) compared with wild-type cells. The incubation of U373MGsiGST6 cells with 75 µM aminochrome resulted in the formation of autophagic vacuoles containing undigested cellular components, as determined using transmission electron microscopy. A significant increase in autophagosomes was determined by measuring endogenous LC3-II, a significant decrease in cell death was observed in the presence of bafilomycin A1, and a significant increase in cell death was observed in the presence of trehalose. A significant increase in LAMP2 immunostaining was observed, a significant decrease in bright red fluorescence of lysosomes with acridine orange was observed, and bafilomycin A1 pretreatment reduced the loss of lysosome acidity. A significant increase in cell death was observed in the presence of lysosomal protease inhibitors. Aggregation of TUBA/α-tubulin (tubulin, α) and SQSTM1 protein accumulation were also observed. Moreover, a significant increase in the number of lipids droplets was observed compared with U373MG cells with normal expression of GSTM2. These results support the notion that GSTM2 is a protective enzyme against aminochrome toxicity in astrocytes and that aminochrome cell death in U373MGsiGST6 cells involves autophagic-lysosomal dysfunction. 相似文献