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21.
Cultured human endothelial cells synthesize and secrete both fibronectin and factor VIII-related antigen (VIIIR:Ag). In immunofluorescence microscopy, intracellular fibronectin was seen diffusely perinuclearly whereas VIIIR:Ag was located both diffusely in the perinuclear cytoplasm and in distinct rod-shaped granules. These granules could, moreover, be visualized with fluorochrome-coupled Ricinus communis agglutinin I (RCA), which also stained the Golgi apparatus as a reticular juxtanuclear structure, and they were identified as Weibel-Palade bodies by immunoelectron microscopy. Puromycin treatment depleted intracellular fibronectin but did not affect the granular localization of VIIIR:Ag. A short exposure of the cells to monensin caused a juxtanuclear accumulation of fibronectin at the Golgi region whereas VIIIR:Ag only was seen in rounded cytoplasmic granules. A prolonged monensin treatment brought about a cytoplasmic accumulation of fibronectin-containing vesicles whereas VIIIR:Ag showed no accumulation and there was no codistribution between granules containing fibronectin or VIIIR:Ag. Type IV procollagen, on the other hand, was distinctly co-localized with fibronectin. In monensin-treated cells RCA mainly stained the VIIIR:Ag-containing vesicles whereas Concanavalin A (Con A) appeared to label the fibronectin-containing vesicles. Immunoelectron microscopy of these cells revealed VIIIR:Ag in some vacuolar structures and typical Weibel-Palade bodies could not be identified. Exposure of the cells to tunicamycin, on the other hand, caused a prominent cytoplasmic accumulation of VIIIR:Ag and, within 96 h, led to the disappearance of most of the VIIIR:Ag-positive granules but did not affect the intracellular distribution of fibronectin. These results, which show that metabolical inhibitors affect differently the intracellular compartmentalization of fibronectin and VIIIR:Ag, indicate, that the two glycoproteins have divergent intracellular pathways in cultured human endothelial cells. 相似文献
22.
J.A. Virtanen J.R. Brotherus O. Renkonen M. Kates 《Chemistry and physics of lipids》1980,27(3):185-190
Stereochemically pure 2,3-dipalmitoyl-sn-glycerol and 2,3-dioleoyl-sn-glycerol were prepared in an overall yield of 20% by a new and facile method starting from D-mannitol. The synthetic intermediates were 1,6-ditrityl-D-mannitol (1), 1-trityl-sn-glycerol (2), and 1-trityl-2,3-diacyl-sn-glycerol (3). The key reaction was the oxidation of 1 with lead tetraacetate followed by reduction with sodium borohydride. The product (2) was readily separated from the only byproduct, tritylethyleneglycol. 相似文献
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P Aula H von Koskull K Teramo O Karjalainen I Virtanen V P Lehto D Dahl 《BMJ (Clinical research ed.)》1980,281(6253):1456-1457
Rapidly adhering cells (RA cells) from the amniotic fluid of a pregnancy with fetal anencephaly were investigated by immunofluorescence assay with an antiserum against glial cells. After 24 hours'' cultivation a high proportion of the cells showed positive glial-specific fluorescence, whereas no staining was seen in cells from samples of normal amniotic fluid. At the 24th week the mother was delivered of a stillborn infant with anencephaly. Immunofluorescence staining of RA cells with glial-specific antiserum may be used for the differential diagnosis of fetal abnormalities associated with a high alpha-fetoprotein concentration in amniotic fluid. 相似文献
26.
U Kj?rell L E Thornell V P Lehto I Virtanen R G Whalen 《European journal of cell biology》1987,44(1):68-78
The intermediate filament (IF) composition of muscle cells of various sources is still a controversial issue. In the present study, the IF composition of bovine Purkinje fibres (PFs), atrial and ventricular myocardium, and gastric smooth muscle (SM) has been compared using biochemical and immunocytochemical methods. The Mr of the major IF subunit protein in all four tissues was 55,000. In two-dimensional (2-D) electrophoresis gels of Triton-treated ordinary atrial and ventricular myocardium and the gastric muscular wall, two or three isoelectric isoforms were seen, whereas in PFs up to seven isoforms caused by phosphorylation were observed. In immunofluorescence studies antibodies against the Mr 55,000 subunit of PFs and gastric SM, respectively, both showed identical reactivity with PFs, atrial and ventricular myocytes, gastric SM cells and some SM cells in intramyocardial and gastric muscular wall blood vessels. A small amount of vimentin (Mr 57,000) was also detected in 2-D gel electrophoresis in all four tissues as well as in immunoblotting of PFs with antibodies to vimentin. Immunofluorescence studies using both polyclonal and monoclonal antibodies to vimentin showed that vimentin was present in the endothelium and SM cells of both intramyocardial and gastric muscular wall vessels, sometimes together with desmin in the vascular SM cells, but was never seen in PF, atrial, ventricular or gastric SM cells proper. As expected, vimentin was present in interstitial tissue, i.e., fibroblasts and capillaries. However, interestingly, the monoclonal antibodies, which recognized different antigenic determinants of vimentin, did not give identical staining patterns. Especially the staining of the vascular SM cells differed. Since this staining pattern did not change upon denaturation and unmasking experiments, it seems that the organization of vimentin in different mesenchymal cell types varies. Vimentin was also detected in isolated PFs but here it was located solely in the contaminating interstitial tissue. Thus, desmin is the sole IF protein expressed in PFs, in atrial and ventricular myocytes and in gastric SM cells proper; vimentin alone being present in the interstitial tissue cells, whilst in vascular SM cells desmin and vimentin are coexpressed in various proportions. The variation in number of isoforms of desmin and the heterogeneity in staining of mesenchymal tissues with monoclonal vimentin antibodies probably indicates that the IF cytoskeletons are differently organized in various cell types, even though they contain IFs of the same class. 相似文献
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Photosynthesis Research - Most photosynthetic organisms are sensitive to very high light, although acclimation mechanisms enable them to deal with exposure to strong light up to a point. Here we... 相似文献
29.
Kirsi A. Virtanen Wouter D. van Marken Lichtenbelt Pirjo Nuutila 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(5):1004-1008
Human adults have functionally active BAT. The metabolic function can be reliably measured in vivo using modern imaging modalities (namely PET/CT). Cold seems to be one of the most potent stimulators of BAT metabolic activity but other stimulators (for example insulin) are actively studied. Obesity is related to lower metabolic activity of BAT but it may be reversed after successful weight reduction such as after bariatric surgery. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease. 相似文献
30.
Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe 总被引:1,自引:0,他引:1
Jonathan Lenoir Bente Jessen Graae Per Arild Aarrestad Inger Greve Alsos W. Scott Armbruster Gunnar Austrheim Claes Bergendorff H. John B. Birks Kari Anne Bråthen Jörg Brunet Hans Henrik Bruun Carl Johan Dahlberg Guillaume Decocq Martin Diekmann Mats Dynesius Rasmus Ejrnæs John‐Arvid Grytnes Kristoffer Hylander Kari Klanderud Miska Luoto Ann Milbau Mari Moora Bettina Nygaard Arvid Odland Virve Tuulia Ravolainen Stefanie Reinhardt Sylvi Marlen Sandvik Fride Høistad Schei James David Mervyn Speed Liv Unn Tveraabak Vigdis Vandvik Liv Guri Velle Risto Virtanen Martin Zobel Jens‐Christian Svenning 《Global Change Biology》2013,19(5):1470-1481
Recent studies from mountainous areas of small spatial extent (<2500 km2) suggest that fine‐grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate‐change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine‐grained thermal variability across a 2500‐km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000‐m2 units (community‐inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1‐km2 units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1‐km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100‐km2 units. Ellenberg temperature indicator values in combination with plant assemblages explained 46–72% of variation in LmT and 92–96% of variation in GiT during the growing season (June, July, August). Growing‐season CiT range within 1‐km2 units peaked at 60–65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography‐related variables and latitude explained 35% of variation in growing‐season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing‐season CiT within 100‐km2 units was, on average, 1.8 times greater (0.32 °C km?1) than spatial turnover in growing‐season GiT (0.18 °C km?1). We conclude that thermal variability within 1‐km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains. 相似文献