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81.
Neisseria meningitidis expressing lgtB lipopolysaccharide targets DC-SIGN and modulates dendritic cell function 总被引:2,自引:0,他引:2
Steeghs L van Vliet SJ Uronen-Hansson H van Mourik A Engering A Sanchez-Hernandez M Klein N Callard R van Putten JP van der Ley P van Kooyk Y van de Winkel JG 《Cellular microbiology》2006,8(2):316-325
Neisseria meningitidis lipopolysaccharide (LPS) has been identified as a major determinant of dendritic cell (DC) function. Here we report that one of a series of meningococcal mutants with defined truncations in the lacto-N-neotetraose outer core of the LPS exhibited unique strong adhesion and internalization properties towards DC. These properties were mediated by interaction of the GlcNAc(beta1-3)-Gal(beta1-4)-Glc-R oligosaccharide outer core of lgtB LPS with the dendritic-cell-specific ICAM-3 grabbing non-integrin (DC-SIGN) lectin receptor. Activation of DC-SIGN with this novel oligosaccharide ligand skewed T-cell responses driven by DC towards T helper type 1 activity. Thus, the use of lgtB LPS may provide a powerful instrument to selectively induce the desired arm of the immune response and potentially increase vaccine efficacy. 相似文献
82.
Anita Murray Salvatore Cerchio Robert McCauley Curt S. Jenner Yvette Razafindrakoto Douglas Coughran Shannon McKay Howard Rosenbaum 《Marine Mammal Science》2012,28(1):E41-E57
Comparing humpback whale song from different breeding assemblages can reveal similarities in song due to acoustically interacting males, and therefore indirectly test whether males from different breeding sites are mixing. Northern Hemisphere song comparisons illustrated that whales within ocean basins share similar songs and are subpopulations within a larger population, whereas whales in different ocean basins are isolated populations and therefore do not share songs. During the 2006 breeding season, recordings were collected in Madagascar and Western Australia, and were compared visually plus aurally. Both regions shared one theme, whereas each region had four and six private themes, respectively. This study had a substantially low number of shared themes. The co‐occurrence of one theme was interpreted as an indication of limited exchange between these breeding assemblages, and we speculate that limited song similarity is due to inter‐oceanic interactions. Male(s) from an Indian Ocean breeding group could be exposed to novel song when they geographically overlap, and acoustically interact, with males from a different ocean basin. Novel song could induce rapid temporal changes as new song content is incorporated, thereby minimizing song similarities between that breeding group and other Indian Ocean breeding groups that were not exposed to the novel song. 相似文献
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Lecat A Di Valentin E Somja J Jourdan S Fillet M Kufer TA Habraken Y Sadzot C Louis E Delvenne P Piette J Legrand-Poels S 《The Journal of biological chemistry》2012,287(35):29213-29226
NOD2 is one of the best characterized members of the cytosolic NOD-like receptor family. NOD2 is able to sense muramyl dipeptide, a specific bacterial cell wall component, and to subsequently induce various signaling pathways leading to NF-κB activation and autophagy, both events contributing to an efficient innate and adaptive immune response. Interestingly, loss-of-function NOD2 variants were associated with a higher susceptibility for Crohn disease, which highlights the physiological importance of proper regulation of NOD2 activity. We performed a biochemical screen to search for new NOD2 regulators. We identified a new NOD2 partner, c-Jun N-terminal kinase-binding protein 1 (JNKBP1), a scaffold protein characterized by an N-terminal WD-40 domain. JNKBP1, through its WD-40 domain, binds to NOD2 following muramyl dipeptide activation. This interaction attenuates NOD2-mediated NF-κB activation and IL-8 secretion as well as NOD2 antibacterial activity. JNKBP1 exerts its repressor effect by disturbing NOD2 oligomerization and RIP2 tyrosine phosphorylation, both steps required for downstream NOD2 signaling. We furthermore showed that JNKBP1 and NOD2 are co-expressed in the human intestinal epithelium and in immune cells recruited in the lamina propria, which suggests that JNKBP1 contributes to maintain NOD2-mediated intestinal immune homeostasis. 相似文献
85.
HF Araújo PC Campos DR Camargo FN Pereira ML Samuel MA Oliveira CL Fortes-Dias SY Leclercq 《Canadian journal of microbiology》2012,58(9):1055-1062
Vaccination is the most promising strategy to reduce the incidence of pneumococcal infection. Although there are vaccines available, all of them are based on polysaccharide antigens (conjugated or not). In addition to their high cost, those vaccines do not cover all serotypes. To overcome these hindrances, we evaluated the immunogenicity and the protective efficacy of the S9 ribosomal protein of Streptococcus pneumoniae with the aim of developing a protein-based vaccine in the future. The gene encoding the S9 ribosomal protein was cloned in pET21-a expression vector, and the recombinant S9 protein was used to immunize mice. Significantly higher levels of anti-S9 immunoglobulin G were achieved (with predominance of immunoglobulin G1) in comparison with the control. Antibodies elicited against S.?pneumoniae protein extract in rabbit recognized the recombinant S9 protein by Western blot, thus demonstrating its immunogenicity. Moreover, mice immunized with recombinant S9 protein and challenged with a virulent strain of S.?pneumoniae presented a significant reduction of bacteremia after 24?h of infection as compared with the control. However, in the S9-immunized mice the onset of death was insignificantly delayed, but all of them died by the fourth day postinfection. 相似文献
86.
Goekint M Bos I Heyman E Meeusen R Michotte Y Sarre S 《Journal of applied physiology (Bethesda, Md. : 1985)》2012,112(4):535-541
Hippocampal brain-derived neurotrophic factor (BDNF) protein is increased with exercise in rats. Monoamines seem to play a role in the regulation of BDNF, and monoamine neurotransmission is known to increase with exercise. The purpose of this study was to examine the influence of acute exercise on monoaminergic neurotransmission and BDNF protein concentrations. Hippocampal microdialysis was performed in rats that were subjected to 60 min of treadmill running at 20 m/min or rest. Two hours postexercise, the rats were killed, and the hippocampus was dissected. In experiments without microdialysis, hippocampus and serum samples were collected immediately after exercise. Exercise induced a twofold increase in hippocampal dopamine release. Noradrenaline and serotonin release were not affected. Hippocampal BDNF levels were not influenced, whether they were measured immediately or 2 h after the exercise protocol. Serum BDNF levels did not change either, but serum BDNF was negatively correlated to peripheral corticosterone concentrations, indicating a possible inhibitory reaction to the stress of running. Sixty minutes of exercise enhances dopamine release in the hippocampus of the rat in vivo. However, this increase is not associated with changes in BDNF protein levels immediately nor 2 h after the acute exercise bout. An increased corticosterone level might be the contributing factor for the absence of changes in BDNF. 相似文献
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88.
Connecting the dots between PubMed abstracts 总被引:1,自引:0,他引:1
89.
Darwin’s naturalization hypothesis predicts that successful invaders will tend to differ taxonomically from native species
in recipient communities because less related species exhibit lower niche overlap and experience reduced biotic resistance.
This hypothesis has garnered substantial support at coarse scales. However, at finer scales, the influence of traits and niche
use on invasibility and invader impacts is poorly understood. Within grasslands of western Montana, USA, we compared morphological
and phenological traits for five top exotic invasive forbs and five dominant native forbs using multivariate techniques to
examine niche separation between exotics and natives. Exotic forbs differed from native forbs in multivariate space. Phenologically,
native forbs synchronized vegetative growth with bolting and flowering early in spring. In contrast, exotics initiated vegetative
growth concurrent with natives but bolted and flowered later. Morphologically, vegetative growth of exotics was three times
shorter and narrower, but flowering stem growth was 35% taller and 65% wider than the natives. Collectively, these patterns
suggest different strategies of resource uptake and allocation. Additionally, following wildfire, survival was four times
higher for exotics compared to natives, and three times more of the surviving exotics flowered. The exotics we examined appeared
to be exploiting an empty community-level niche. The resulting pattern of trait differences between exotics and natives suggests
a predictable pattern of invasion and a predictable trajectory of community change. Our results illustrate how quantifying
trait differences between invading exotics and natives at the within-community scale can improve understandings of community
invasibility and invader impacts. 相似文献
90.