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121.
In innate immunity, dead and dying cells release internal constituents that can serve as damage-associated molecular patterns (DAMPs) or alarmins. This release occurs more abundantly during necrosis than apoptosis and may account for the differences in the immunologic properties of these death forms. To elucidate DAMP release in necrosis, we compared the levels of two nuclear molecules (DNA and HMGB1, a non-histone protein with alarmin activity) in media following necrosis of Jurkat T cells by freeze-thawing, ethanol, heat or hydrogen peroxide treatment. In our experiments, DNA release was measured by fluorimetry with the dye PicoGreen, while HMGB1 was measured by Western blotting. As the results of our study show, each form of necrosis is associated with a distinct pattern of DNA and HMGB1 release with respect to kinetics and amounts. Of these, freeze-thawing produced the highest and most rapid increase in HMGB1 and DNA levels, although the released DNA was subject to nuclease digestion; in addition, freeze-thawing led to the production of particles measured by flow cytometry. Together, these results indicate that experimental necrosis leads to diverse patterns of nuclear molecule release which could affect their immunologic activity. 相似文献
122.
Popov A Driesen J Abdullah Z Wickenhauser C Beyer M Debey-Pascher S Saric T Kummer S Takikawa O Domann E Chakraborty T Krönke M Utermöhlen O Schultze JL 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(7):4976-4988
Myeloid dendritic cells (DC) and macrophages play an important role in pathogen sensing and antimicrobial defense. In this study we provide evidence that myeloid DC respond to infection with Listeria monocytogenes with simultaneous induction of multiple stimulatory and inhibitory molecules. However, the overall impact of infected DC during T cell encounter results in suppression of T cell activation, indicating that inhibitory pathways functionally predominate. Inhibitory activity of infected DC is effected mainly by IL-10 and cyclooxygenase 2-mediated mechanisms, with soluble CD25 acting as an IL-2 scavenger as well as by the products of tryptophan catabolism. These inhibitory pathways are strictly TNF-dependent. In addition to direct infection, DC bearing this regulatory phenotype can be induced in vitro by a combination of signals including TNF, TLR2, and prostaglandin receptor ligation and by supernatants derived from the infected cells. Both infection-associated DC and other in vitro-induced regulatory DC are characterized by increased resistance to infection and enhanced bactericidal activity. Furthermore, myeloid DC expressing multiple regulatory molecules are identified in vivo in granuloma during listeriosis and tuberculosis. Based on the in vivo findings and the study of in vitro models, we propose that in granulomatous infections regulatory DC may possess dual function evolved to protect the host from disseminating infection via inhibition of granuloma destruction by T cells and control of pathogen spreading. 相似文献
123.
124.
Huge V Lauchart M Förderreuther S Kaufhold W Valet M Azad SC Beyer A Magerl W 《PloS one》2008,3(7):e2742
Background
Sensory abnormalities are a key feature of Complex Regional Pain Syndrome (CRPS). In order to characterise these changes in patients suffering from acute or chronic CRPS I, we used Quantitative Sensory Testing (QST) in comparison to an age and gender matched control group.Methods
61 patients presenting with CRPS I of the upper extremity and 56 healthy subjects were prospectively assessed using QST. The patients'' warm and cold detection thresholds (WDT; CDT), the heat and cold pain thresholds (HPT; CPT) and the occurrence of paradoxical heat sensation (PHS) were observed.Results
In acute CRPS I, patients showed warm and cold hyperalgesia, indicated by significant changes in HPT and CPT. WDT and CDT were significantly increased as well, indicating warm and cold hypoaesthesia. In chronic CRPS, thermal hyperalgesia declined, but CDT as well as WDT further deteriorated. Solely patients with acute CRPS displayed PHS. To a minor degree, all QST changes were also present on the contralateral limb.Conclusions
We propose three pathomechanisms of CRPS I, which follow a distinct time course: Thermal hyperalgesia, observed in acute CRPS, indicates an ongoing aseptic peripheral inflammation. Thermal hypoaesthesia, as detected in acute and chronic CRPS, signals a degeneration of A-delta and C-fibres, which further deteriorates in chronic CRPS. PHS in acute CRPS I indicates that both inflammation and degeneration are present, whilst in chronic CRPS I, the pathomechanism of degeneration dominates, signalled by the absence of PHS. The contralateral changes observed strongly suggest the involvement of the central nervous system. 相似文献125.
Alexandre Uezu Dennis Driesmans Beyer Jean Paul Metzger 《Biodiversity and Conservation》2008,17(8):1907-1922
In fragmented landscapes, agroforest woodlots can potentially act as stepping stones facilitating movement between forest
fragments. We assessed the influence of agroforest woodlots on bird distribution and diversity in the Atlantic forest region
(SE Brazil), and also tested which categories of species can use different types of connection elements, and whether this
use is influenced by the distance to large forest patches. We studied two fragmented landscapes, with and without stepping
stones linking large fragments, and one forested landscape. Using a point count, a bird survey was undertaken in the fragmented
landscapes in five different elements: large remnants (>400 ha), agroforest woodlots (0.4–1.1 ha), small patches (0.5–7 ha),
riparian corridor, and pasture areas (the main matrix). Generalist and open-area species were commonly observed in the agroforest
system or other connection elements, whereas only a few forest species were present in these connections. For the latter species,
the distance of woodlots to large patches was essential to determine their richness and abundance. Based on our results and
data from literature, we suggest that there is an optimal relationship between the permeability of the matrix and the efficiency
of stepping stones, which occurs at intermediate degrees of matrix resistance, and is species-dependent. Because the presence
of agroforest system favors a higher richness of generalist species, they appeared to be more advantageous for conservation
than the monoculture system; for this reason, they should be considered as a management alternative, particularly when the
matrix permeability requirement is met. 相似文献
126.
127.
Eric C. Beyer Joanna Gemel AgustÍ N Martí nez Viviana M. Berthoud Virginijus Valiunas Alonso P. Moreno Peter R. Brink 《Cell communication & adhesion》2001,8(4):199-204
Cx43 is widely expressed in many different cell types, and many of these cells also express other connexins. If these connexins are capable of mixing, the functional properties of channels containing heteromeric connexons may substantially influence intercellular communication between such cells. We used biochemical strategies (sedimentation through sucrose gradients, co-immunoprecipitation, or co-purification by Ni-NTA chromatography) to examine heteromeric mixing of Cx43 with other connexins (including Cx26, Cx37, Cx40, Cx45, and Cx56) in transfected cells. These analyses showed that all of the tested connexins except Cx26 formed heteromeric connexons with Cx43. We used the double whole-cell patch-camp technique to analyze the electrophysiological properties of gap junction channels in pairs of co-expressing cells. Cx37 and Cx45 made a large variety of functional heteromeric combinations with Cx43 based on detection of many different single channel conductances. Most of the channel event sizes observed in cells co-expressing Cx40 and Cx43 were similar to those of homomeric Cx43 or Cx40 hemichannels in homo- or hetero-typic configurations. Our data suggest several different possible consequences of connexin co-expression: (1) some combinations of connexins may form heteromeric connexons with novel proeprties; (2) some connexins may form heteromeric channels that do not have unique properties, and (3) some connexins may be incompatible for heteromeric mixing. 相似文献
128.
Adolf Beyer 《Planta》1928,5(3):478-519
Ohne ZusammenfassungMit 2 Textabbildungen. 相似文献
129.
130.
R. Beyer 《Plant Systematics and Evolution》1894,44(5):167-169
Ohne Zusammenfassung 相似文献