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101.
Ringvall M Thulin Å Zhang L Cedervall J Tsuchida-Straeten N Jahnen-Dechent W Siegbahn A Olsson AK 《PloS one》2011,6(1):e14526
Background
The heparin-binding plasma protein histidine-rich glycoprotein (HRG; alternatively, HRGP/HPRG) can suppress tumor angiogenesis and growth in vitro and in vivo. Mice lacking the HRG gene are viable and fertile, but have an enhanced coagulation resulting in decreased bleeding times. In addition, the angiogenic switch is significantly enhanced in HRG-deficient mice.Methodology/Principal Findings
To address whether HRG deficiency affects tumor development, we have crossed HRG knockout mice with the RIP1-Tag2 mouse, a well established orthotopic model of multistage carcinogenesis. RIP1-Tag2 HRG−/− mice display significantly larger tumor volume compared to their RIP1-Tag2 HRG+/+ littermates, supporting a role for HRG as an endogenous regulator of tumor growth. In the present study we also demonstrate that platelet activation is increased in mice lacking HRG. To address whether this elevated platelet activation contributes to the increased pathological angiogenesis in HRG-deficient mice, they were rendered thrombocytopenic before the onset of the angiogenic switch by injection of the anti-platelet antibody GP1bα. Interestingly, this treatment suppressed the increase in angiogenic neoplasias seen in HRG knockout mice. However, if GP1bα treatment was initiated at a later stage, after the onset of the angiogenic switch, no suppression of tumor growth was detected in HRG-deficient mice.Conclusions
Our data show that increased platelet activation mediates the accelerated angiogenic switch in HRG-deficient mice. Moreover, we conclude that platelets play a crucial role in the early stages of tumor development but are of less significance for tumor growth once angiogenesis has been initiated. 相似文献102.
Leif Holmquist Corresp. Author Agneta Ekebom Kerstin Alm Kübler Olof Vesterberg 《Grana》2013,52(2):104-107
In the present study, the airborne concentrations of birch and oak pollen grains and birch pollen allergens have been recorded in samples from a common sampling station in Stockholm. The sampling period was between April 22nd and May 31st 2003. The objectives were to evaluate if analysis of allergen particles in parallel with pollen grains would be relevant to aid subjects suffering from pollinosis. Days with low birch pollen counts had relatively high nominal allergen concentrations in the beginning of the sampling period. The birch pollen grain concentration peaks, during the dry pollination culmination interval in the middle of the period, were associated with correspondingly lower nominal concentrations of allergens than grains. At the end of the sampling period very high nominal amounts of allergen appeared, as reflected by high concentrations of oak pollen grains. The high allergen concentrations were obtained as a result of inherent cross‐reactivity of anti‐ Bet v 1 antibodies with Que a antigens, which are immunologically analogous with Bet v 1. Allergen concentrations increased and decreased after light and heavy rain, respectively. Results obtained indicate that adding a pollen count forecast with allergen concentration data should aid pollen allergic subjects to avoid particulate allergens which might be expected to penetrate more easily than pollen grains into indoor environments. 相似文献
103.
Airborne concentrations of pollen from Betula (birch), Poaceae (grasses) and Artemisia (mugwort) are compared during a seven year period (90–96) with respect to both quantitative and seasonal aspects, at three different sampling sites, one in Estonia (Tartu) and two in Sweden (Stockholm and Roma on the island of Gotland). All three taxa occur in the region and are well‐known causes of allergic sensitisation. The annual total and peak values of birch, grass and mugwort pollen were found to be much higher in Tartu than in Stockholm and Roma. Both the birch and the grass pollen seasons ended later in Stockholm than in Roma and Tartu. The mugwort flowering season always began earlier in Stockholm than at the other sites, and more days elapsed between start day and peak day in Stockholm than in Tartu. 相似文献
104.
Philipp Assmy Jens K. Ehn Mar Fernández-Méndez Haakon Hop Christian Katlein Arild Sundfjord Katrin Bluhm Malin Daase Anja Engel Agneta Fransson Mats A. Granskog Stephen R. Hudson Svein Kristiansen Marcel Nicolaus Ilka Peeken Angelika H. H. Renner Gunnar Spreen Agnieszka Tatarek Jozef Wiktor 《PloS one》2013,8(10)
During two consecutive cruises to the Eastern Central Arctic in late summer 2012,
we observed floating algal aggregates in the melt-water layer below and between
melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter)
aggregates had a mucous consistency and were dominated by typical ice-associated
pennate diatoms embedded within the mucous matrix. Aggregates maintained
buoyancy and accumulated just above a strong pycnocline that separated meltwater
and seawater layers. We were able, for the first time, to obtain quantitative
abundance and biomass estimates of these aggregates. Although their biomass and
production on a square metre basis was small compared to ice-algal blooms, the
floating ice-algal aggregates supported high levels of biological activity on
the scale of the individual aggregate. In addition they constituted a food
source for the ice-associated fauna as revealed by pigments indicative of
zooplankton grazing, high abundance of naked ciliates, and ice amphipods
associated with them. During the Arctic melt season, these floating aggregates
likely play an important ecological role in an otherwise impoverished
near-surface sea ice environment. Our findings provide important observations
and measurements of a unique aggregate-based habitat during the 2012 record sea
ice minimum year. 相似文献
105.
The annually reoccurring blooms that characterize the surface waters of the Baltic Sea are dominated by filamentous, heterocystous cyanobacteria such as Nodularia spumigena. In a previous study, we have demonstrated that N. spumigena strain AV1 differentiates heterocysts in the absence of detectable nitrogen fixation activity, an unusual physiological trait that is clearly distinct from other well-studied cyanobacteria. To further analyze the uncoupling between these two processes, we analyzed the gene expression and modification of the nitrogenase enzyme (the enzyme responsible for nitrogen fixation) in N. spumigena AV1, as well as in several other N. spumigena strains. Here, we demonstrate the occurrence of two nifH gene copies in N. spumigena strain AV1, only one of which is located in a complete nifHDK cluster and several NifH protein forms. Furthermore, we demonstrate the occurrence of a DNA rearrangement mechanism acting within the nifH gene copy located in the nifHDK cluster and present only in the strains exhibiting the previously reported uncoupling between heterocyst differentiation and nitrogen fixation processes. These data stress the existence of a distinct and complex regulatory circuit related to nitrogen fixation in this ecologically significant bloom-forming cyanobacterium. 相似文献
106.
Long-lasting decrease in viremia in macaques chronically infected with simian immunodeficiency virus SIVmac251 after therapeutic DNA immunization
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von Gegerfelt AS Rosati M Alicea C Valentin A Roth P Bear J Franchini G Albert PS Bischofberger N Boyer JD Weiner DB Markham P Israel ZR Eldridge JH Pavlakis GN Felber BK 《Journal of virology》2007,81(4):1972-1979
Rhesus macaques chronically infected with highly pathogenic simian immunodeficiency virus (SIV) SIVmac251 were treated with antiretroviral drugs and vaccinated with combinations of DNA vectors expressing SIV antigens. Vaccination during therapy increased cellular immune responses. After the animals were released from therapy, the virus levels of 12 immunized animals were significantly lower (P = 0.001) compared to those of 11 animals treated with only antiretroviral drugs. Vaccinated animals showed a persistent increase in immune responses, thus indicating both a virological and an immunological benefit following DNA therapeutic vaccination. Several animals show a long-lasting decrease in viremia, suggesting that therapeutic vaccination may provide an additional benefit to antiretroviral therapy. 相似文献
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