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Transient light-induced changes in ion channel and proton pump activities in the plasma membrane of tobacco mesophyll protoplasts 总被引:3,自引:0,他引:3
Blom-Zandstra Margaretha; Koot Hans; van Hattum Joke; Vogelzang Sake A. 《Journal of experimental botany》1997,48(9):1623-1630
Rapid, transient changes of the membrane potential upon lighttransitions are generally observed in microelectrode studies.In a patch-clamp study similar responses to light transitionswere found in current clamp. Corresponding with the changesof membrane potential, light-induced current changes in voltageclamp were observed. This paper evaluates the involvement ofoutward rectifying conductances and plasma membrane bound H+-ATpases(proton pump) to these light responses in mesophyll protoplastsof Nicotiana tabacum L. The contribution of K+-channels to theseresponses, could be minimized by variation of the holding potentialor addition of the K+-channel blocker verapamil. It was concludedthat light transitions modulate both proton pump and K+-channelactivity. Effects of light on membrane current were not observedin root cells and chlorophyll-deficient cells, suggesting thatthe response requires photosynthetic activity. However, blockersof photosystems I and II did not affect current changes. Key words: Light, patch-clamp, plasma membrane, tobacco, whole cell 相似文献
155.
The central nervous system of flatworms has been regarded as comprised of the bilobed brain, the longitudinal cords and the
connecting transverse commissures forming a so called orthogon. The peripheral nervous system comprises the submuscular and
subepidermal plexuses. As a confusion in the terminology of the longitudinal nerve cords has prevailed, two concepts have
been introduced, the main nerve cords (MCs) and the minor cords. The MCs have been defined as the pair of longitudinal nerve
cords that (1) start with strongest roots in the brain, (2) consist of wide fibre bundles and (3) are associated with more
neurons (particularly amninergic marker neurons) than the other cords. Longitudinal nerve cords in other positions are thinner
and have less pronounced contact with the brain. They have collectively been named minor cords. Support for the special status
of the MCs has been obtained from studies of the neuroanatomy of Catenulida, Macrostomida, Proseriata, Tricladida and Lecithoepitheliata
and of parasitic flatworms. Using the above mentioned criteria for the MCs and the results of recent studies, we present the
following hypothese: The MCs in all flatworms correspond to each other and have a common origin.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Rudolf Hänsel Margaretha Kartarahardja Jai-Tung Huang Ferdinand Bohlmann 《Phytochemistry》1980,19(5):857-861
The investigation of the roots and the aerial parts of Taraxacum officinale afforded, in addition to known compounds, a new eudesmanolide, a tetrahydroridentin B, a eudesmanolide-β-d-glucopyranoside and two germacranolide acids, which are esterified with β-d-glucose. The latter two seem to represent a new type of sesquiterpene lactone. All three of the new glucose derivatives have a strong bitter taste. The structures were elucidated by intensive NMR studies and by some chemical transformations. 相似文献
158.
Katarina Tejle Margaretha Lindroth Karl-Eric Magnusson & Birgitta Rasmusson 《FEMS microbiology letters》2008,279(1):92-102
The protective immune response against the parasite, including the role of dendritic cells (DC) in the course of infection, plays a fundamental role. This study shows that wild-type (WT) Leishmania promastigotes and specifically the phosphoglycans family of virulence-associated antigens inhibit human monocyte-derived dendritic cells (MoDC) maturation and detachment to distinct surfaces. Immature phagocytosis of Leishmania donovani promastigotes by immature MoDC results in the increased expression of CD11b and CD51, and inhibition of cell detachment to distinct surfaces, which was dependent on the presence of phosphoglycans. These findings demonstrate that phosphoglycans of WT L. donovani might also inhibit human DC migration to lymphoid organs. 相似文献