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61.
62.
Erich Hesse 《Journal of Ornithology》1919,67(4):392-430
Ohne Zusammenfassung 相似文献
63.
Erich Hesse 《Journal of Ornithology》1917,65(2):112-115
Ohne Zusammenfassung 相似文献
64.
Erich Hesse 《Journal of Ornithology》1916,64(4):605-611
Ohne Zusammenfassung 相似文献
65.
Erich Hesse 《Journal of Ornithology》1909,57(3):322-365
Ohne Zusammenfassung 相似文献
66.
Pollenkitt – its composition, forms and functions 总被引:1,自引:1,他引:0
Two types of sticky pollen coat material exist in angiosperms, both produced by the anther tapetum. Pollenkitt is the most common adhesive material present around pollen grains of almost all angiosperms pollinated by animals, whereas tryphine seems to be restricted only to Brassicaceae. Tapetal cell protoplasts have different patterns of development according to the products formed during their development and degeneration. If tryphine is formed, the tapetal cell protoplasts lose their individuality at the microspore stage. If pollenkitt is formed, their contents degenerate at later stages. Cell content is totally reabsorbed, when ripe pollen is not surrounded by any gluing material. Current knowledge of pollenkitt formation, deposition on pollen grains and chemical composition are reviewed and discussed. Methods for detecting this viscous fluid are also presented. The many functions of pollenkitt, deduced from personal observations and the literature, act in the period between anther opening and pollen hydration on the stigma; they are: (1) to hold pollen in the anther until dispersal; (2) to enable secondary pollen presentation; (3) to facilitate pollen dispersal; (4) to protect pollen from water loss; (5) to protect pollen from ultra-violet radiation; (6) to maintain sporophytic proteins responsible for pollen–stigma recognition inside exine cavities; (7) to protect pollen protoplasts from fungi and bacteria; (8) to keep together pollen grains during transport; (9) to protect pollen from hydrolysis and exocellular enzymes; (10) to render pollen attractive to animals; (11) to render pollen visible to animal eyes; (12) to hide pollen from animal eyes; (13) to avoid predation of pollen through smell; (14) to enable adhesion to insect bodies; (15) to enable pollen packaging by bees and to form corbicules; (16) to provide a digestible reward for pollinators; (17) to enable pollen clumps to reach the stigma; (18) to allow self-pollination; (19) to facilitate adhesion to the stigma; (20) to facilitate pollen rehydration. Depending on the developmental program of the species, these functions may act during pollen presentation, in relation to pollinators, during pollen dispersal and when pollen reaches the stigma. 相似文献
67.
Bernd Heimrich Daniel-Alexander Hesse Yuan-Ju Wu Sonja Schmid Martin Schwemmle 《Cell and tissue research》2009,338(2):179-190
Granule cells are major targets of entorhinal afferents terminating in a laminar fashion in the outer molecular layer of the
dentate gyrus. Since Borna disease virus (BDV) infection of newborn rats causes a progressive loss of granule cells in the
dentate gyrus, entorhinal fibres become disjoined from their main targets. We have investigated the extent to which entorhinal
axons react to this loss of granule cells. Unexpectedly, anterograde DiI tracing has shown a prominent layered termination
of the entorhinal projection, despite an almost complete loss of granule cells at 9 weeks after infection. Combined light-
and electron-microscopic analysis of dendrites at the outer molecular layer of the dentate gyrus at 6 and 9 weeks post-infection
has revealed a transient increase in the synaptic density of calbindin-positive granule cells and parvalbuminergic neurons
after 6 weeks. In contrast, synaptic density reaches values similar to those of uninfected controls 9 weeks post-infection.
These findings indicate that, after BDV infection, synaptic reorganization processes occur at peripheral dendrites of the
remaining granule cells and parvalbuminergic neurons, including the unexpected persistence of entorhinal axons in the absence
of their main targets. 相似文献
68.
Dmitri Demidov Susann Hesse Annegret Tewes Twan Rutten Jörg Fuchs Raheleh Karimi Ashtiyani Sandro Lein reas Fischer Gunter Reuter Andreas Houben 《The Plant journal : for cell and molecular biology》2009,59(2):221-230
The enzymological properties of AtAurora1, a kinase responsible for the cell cycle-dependent phosphorylation of histone H3 at S10, and its cross-talk with other post-translational histone modifications, were determined. In vitro phosphorylation of H3S10 by AtAurora1 is strongly increased by K9 acetylation, and decreased by K14 acetylation and T11 phosphorylation. However, S10 phosphorylation activity is unaltered by mono-, di- or trimethylation of K9. An interference of H3K9 dimethylation by SUVR4 occurs by a pre-existing phosphorylation at S10. Hence, cross-talk in plants exists between phosphorylation of H3S10 and methylation, acetylation or phosphorylation of neighbouring amino acid residues. AtAurora1 undergoes autophosphorylation in vivo regardless of the presence of substrate, and forms dimers in planta . Of the three ATP-competitive Aurora inhibitors tested, Hesperadin was most effective in reducing the in vivo kinase activity of AtAurora1. Hesperadin consistently inhibited histone H3S10 phosphorylation during mitosis in Arabidopsis cells, but did not affect other H3 post-translational modifications, suggesting a specific inhibition of AtAurora in vivo . Inactivation of AtAurora also caused lagging chromosomes in a number of anaphase cells, but, unlike the situation in mammalian cells, Hesperadin did not influence the microtubule dynamics in dividing cells. 相似文献
69.
Soledad Galli Olaf Jahn Reiner Hitt Doerte Hesse Lennart Opitz Uwe Plessmann Henning Urlaub Juan Jose Poderoso Elizabeth A. Jares-Erijman Thomas M. Jovin 《PloS one》2009,4(10)
Extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) are members of the MAPK family and participate in the transduction of stimuli in cellular responses. Their long-term actions are accomplished by promoting the expression of specific genes whereas faster responses are achieved by direct phosphorylation of downstream effectors located throughout the cell. In this study we determined that hERK1 translocates to the mitochondria of HeLa cells upon a proliferative stimulus. In the mitochondrial environment, hERK1 physically associates with (i) at least 5 mitochondrial proteins with functions related to transport (i.e. VDAC1), signalling, and metabolism; (ii) histones H2A and H4; and (iii) other cytosolic proteins. This work indicates for the first time the presence of diverse ERK-complexes in mitochondria and thus provides a new perspective for assessing the functions of ERK1 in the regulation of cellular signalling and trafficking in HeLa cells. 相似文献
70.
Andreas Wilting Anna Cord Andrew J. Hearn Deike Hesse Azlan Mohamed Carl Traeholdt Susan M. Cheyne Sunarto Sunarto Mohd-Azlan Jayasilan Joanna Ross Aurélie C. Shapiro Anthony Sebastian Stefan Dech Christine Breitenmoser Jim Sanderson J. W. Duckworth Heribert Hofer 《PloS one》2010,5(3)