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91.
Marika Moisseeff 《Anthropological Forum》2017,27(1):34-48
ABSTRACTIn Australian Aboriginal society, personal identity is an evolving process whose successive mutations derive from a person’s capacity to enter into new relationships. Both initiation rites and funerary practices act to mediate such relational transformations. Drawing on Spencer and Gillen’s material on the Arrernte, this paper establishes a parallel between the procedures put into effect to render a son autonomous from his mother in the course of male initiation, and those undertaken to emancipate a widow from her deceased husband. Both ritual operations introduce a relational distancing within a totality. This totality is composed of two individuals whose antecedent close physical intimacy could thwart these persons’ ability to become an autonomous agent. The rituals make the person capable of entering a new intimate relationship: marriage in the case of a son and remarriage in the case of a widow. Both procedures entail the intervention of ritual objects closely connected to an individual’s personal identity: on the one hand, the churinga, a man is joined with at the end of his initiation and which allows him to exercise responsibilities in fertility rites, and on the other hand, the decaying, contaminating corpse a husband leaves behind upon his death. 相似文献
92.
Kai Truusalu Raik-Hiio Mikelsaar Paul Naaber Tõnis Karki Tiiu Kullisaar Mihkel Zilmer Marika Mikelsaar 《BMC microbiology》2008,8(1):132
Background
The aim of the study was to detect whether in experimental Salmonella enterica Typhimurium infection the probiotic Lactobacillus fermentum ME-3 in combination with fluoroquinolone therapy would eradicate S. Typhimurium, prevent the development of liver and spleen granulomas and improve the indices of oxidative stress in the ileum mucosa. 相似文献93.
The role of the Psb28 protein in the structure and function of the photosystem II (PSII) complex has been studied in the cyanobacterium Synechocystis sp. PCC 6803. The protein was localized in the membrane fraction and, whereas most of the protein was detected as an unassembled protein, a small portion was found in the PSII core complex lacking the CP43 antenna (RC47). The association of Psb28 with RC47 was further confirmed by preferential isolation of RC47 from the strain containing a histidine-tagged derivative of Psb28 using nickel-affinity chromatography. However, the affinity-purified fraction also contained a small amount of the unassembled PSII inner antenna CP47 bound to Psb28-histidine, indicating a structural relationship between Psb28 and CP47. A psb28 deletion mutant exhibited slower autotrophic growth than wild type, although the absence of Psb28 did not affect the functional properties of PSII. The mutant showed accelerated turnover of the D1 protein, faster PSII repair, and a decrease in the cellular content of PSI. Radioactive labeling revealed a limitation in the synthesis of both CP47 and the PSI subunits PsaA/PsaB in the absence of Psb28. The mutant cells contained a high level of magnesium protoporphyrin IX methylester, a decreased level of protochlorophyllide, and released large quantities of protoporphyrin IX into the medium, indicating inhibition of chlorophyll (Chl) biosynthesis at the cyclization step yielding the isocyclic ring E. Overall, our results show the importance of Psb28 for synthesis of Chls and/or apoproteins of Chl-binding proteins CP47 and PsaA/PsaB.PSII is a multisubunit pigment-protein complex of plants, algae, and cyanobacteria, which is responsible for oxidation of water and reduction of plastoquinone during oxygenic photosynthesis (Barber, 2006). In the heart of the complex, there are two similar membrane-spanning proteins, D1 and D2, that bind the cofactors involved in primary charge separation (Nanba and Satoh, 1987) and subsequent electron transfer within PSII (for review, see Barber, 2006). Peripherally to the D1-D2 heterodimer, there are two chlorophyll (Chl)-binding inner antenna proteins, CP47 and CP43, that deliver energy to the reaction center (RC), driving electron transfer. In addition, CP43 also provides important ligands to the Mn4Ca cluster, the site of water oxidation (Ferreira et al., 2004; Loll et al., 2005). These four large proteins are surrounded by a number of smaller membrane polypeptides (for review, see Shi and Schröder, 2004). One of them, the so-called PsbW, was originally detected in the isolated RC complex from spinach (Spinacia oleracea; Irrgang et al., 1995; Lorković et al., 1995). The mature protein with a predicted one-transmembrane α-helix in the central hydrophobic region seems to have (unlike most of PSII membrane proteins) the N terminus oriented into the lumen in close vicinity to the extrinsic, nuclear-encoded 33-kD PsbO protein. Cross-linking experiments also indicated a close association of PsbW with D1, D2, and the α-subunit of cytochrome (cyt) b-559 in the isolated RC complex (Irrgang et al., 1995; Lorković et al., 1995). At variance with these results, Rokka et al. (2005) located PsbW predominantly in PSII-light-harvesting complex II (LHCII) supercomplexes and only minor amounts were found in PSII core dimers and monomers. In transgenic plants of Arabidopsis (Arabidopsis thaliana) lacking the PsbW protein, the stability of the dimeric PSII was diminished and the PSII-LHCII supercomplexes could not be detected. It has been suggested that PsbW functions as a linker for LHCII binding to the PSII complex (Shi et al., 2000). Because LHCII is absent in cyanobacteria, it was intelligible that the PsbW was not detected in these oxygenic autotrophs. Nevertheless, N-terminal sequencing and mass spectrometric analyses of protein subunits in the purified His-tagged PSII from Synechocystis sp. PCC 6803 (Synechocystis 6803) revealed the presence of an unknown protein with 16% sequence identity to PsbW from Arabidopsis (Kashino et al., 2002). This protein was designated as Psb28 (also Psb13 or ycf79). Its amino acid sequence suggests that it is a rather hydrophilic protein without a transmembrane helix and is larger than PsbW (about 13 kD). In the recent crystal structures of the cyanobacterial PSII (Ferreira et al., 2004; Loll et al., 2005), this protein was not identified and it remains an issue of contention whether the protein is a true PSII subunit, a transiently associated assembly factor, or just an impurity of the preparation. The relatively low content of this protein in the isolated preparation suggested that the two latter possibilities are more probable. Very recently, the protein has been detected as a component of PSII complexes in Synechocystis depleted of phosphatidylglycerol (Sakurai et al., 2007). It has been proposed that the protein may play a regulatory role during the assembly of PSII. A gene encoding a similar soluble protein has also been found in the genome of Arabidopsis and the protein was designated PsbW-like.Here, we present a detailed analysis of the role of Psb28 in the structure and function of PSII in Synechocystis 6803. The results showed that Psb28 is not a component of the fully assembled dimeric PSII core complex, but it is preferentially bound to PSII assembly intermediates containing the inner antenna CP47. The results support the role of the protein in biogenesis of certain Chl-binding proteins via regulating synthesis of their apoproteins or Chls. 相似文献
94.
95.
Simao Teixeira da Rocha Marika Charalambous Shau-Ping Lin Isabel Gutteridge Yoko Ito Dionne Gray Wendy Dean Anne C. Ferguson-Smith 《PLoS genetics》2009,5(2)
Genomic imprinting is a normal process that causes genes to be expressed according to parental origin. The selective advantage conferred by imprinting is not understood but is hypothesised to act on dosage-critical genes. Here, we report a unique model in which the consequences of a single, double, and triple dosage of the imprinted Dlk1/Pref1, normally repressed on the maternally inherited chromosome, can be assessed in the growing embryo. BAC-transgenic mice were generated that over-express Dlk1 from endogenous regulators at all sites of embryonic activity. Triple dosage causes lethality associated with major organ abnormalities. Embryos expressing a double dose of Dlk1, recapitulating loss of imprinting, are growth enhanced but fail to thrive in early life, despite the early growth advantage. Thus, any benefit conferred by increased embryonic size is offset by postnatal lethality. We propose a negative correlation between gene dosage and survival that fixes an upper limit on growth promotion by Dlk1, and we hypothesize that trade-off between growth and lethality might have driven imprinting at this locus. 相似文献
96.
Roth AL Marzola E Rizzi A Arduin M Trapella C Corti C Vergura R Martinelli P Salvadori S Regoli D Corsi M Cavanni P Caló G Guerrini R 《The Journal of biological chemistry》2006,281(30):20809-20816
Neuropeptide S (NPS) has been recently recognized as the endogenous ligand for the previous orphan G-protein-coupled receptor GPR154, now referred to as the NPS receptor (NPSR). The NPS-NPSR receptor system regulates important biological functions such as sleeping/wakening, locomotion, anxiety, and food intake. To collect information on the mechanisms of interaction between NPS and its receptor, a classical structure-activity relationship study was performed. Human (h) NPS derivatives obtained by Ala and d-scan and N- and C-terminal truncation were assessed for their ability to stimulate calcium release in HEK293 cells expressing the human recombinant NPSR. The results of this study indicate that (i) the effect of hNPS is mimicked by the fragment hNPS-(1-10); (ii) Phe(2), Arg(3), and Asn(4) are crucial for biological activity; (iii) the sequence Thr(8)-Gly(9)-Met(10) is important for receptor activation, although with non-stringent chemical requirements; and (iv) the sequence Val(6)-Gly(7) acts as a hinge region between the two above-mentioned domains. However, the stimulatory effect of hNPS given intracerebroventricularly on mouse locomotor activity was not fully mimicked by hNPS-(1-10), suggesting that the C-terminal region of the peptide maintains importance for in vivo activity. In conclusion, this study identified the amino acid residues of this peptide most important for receptor activation. 相似文献
97.
Kalinchuk AV Lu Y Stenberg D Rosenberg PA Porkka-Heiskanen T 《Journal of neurochemistry》2006,99(2):483-498
Sleep homeostasis is the process by which recovery sleep is generated by prolonged wakefulness. The molecular mechanisms underlying this important phenomenon are poorly understood. Here, we assessed the role of the intercellular gaseous signaling agent NO in sleep homeostasis. We measured the concentration of nitrite and nitrate, indicative of NO production, in the basal forebrain (BF) of rats during sleep deprivation (SD), and found the level increased by 100 +/- 51%. To test whether an increase in NO production might play a causal role in recovery sleep, we administered compounds into the BF that increase or decrease concentrations of NO. Infusion of either a NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, or a NO synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME), completely abolished non-rapid eye movement (NREM) recovery sleep. Infusion of a NO donor, (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2diolate (DETA/NO), produced an increase in NREM that closely resembled NREM recovery after prolonged wakefulness. The effects of inhibition of NO synthesis and the pharmacological induction of sleep were effective only in the BF area. Indicators of energy metabolism, adenosine, lactate and pyruvate increased during prolonged wakefulness and DETA/NO infusion, whereas L-NAME infusion during SD prevented the increases. We conclude that an increase in NO production in the BF is a causal event in the induction of recovery sleep. 相似文献
98.
Harald Biessmann Evi Andronopoulou Max R. Biessmann Vassilis Douris Spiros D. Dimitratos Elias Eliopoulos Patrick M. Guerin Kostas Iatrou Robin W. Justice Thomas Kr?ber Osvaldo Marinotti Panagiota Tsitoura Daniel F. Woods Marika F. Walter 《PloS one》2010,5(3)
Haematophagous insects are frequently carriers of parasitic diseases, including malaria. The mosquito Anopheles gambiae is the major vector of malaria in sub-Saharan Africa and is thus responsible for thousands of deaths daily. Although the role of olfaction in A. gambiae host detection has been demonstrated, little is known about the combinations of ligands and odorant binding proteins (OBPs) that can produce specific odor-related responses in vivo. We identified a ligand, indole, for an A. gambiae odorant binding protein, AgamOBP1, modeled the interaction in silico and confirmed the interaction using biochemical assays. RNAi-mediated gene silencing coupled with electrophysiological analyses confirmed that AgamOBP1 binds indole in A. gambiae and that the antennal receptor cells do not respond to indole in the absence of AgamOBP1. This case represents the first documented instance of a specific A. gambiae OBP–ligand pairing combination, demonstrates the significance of OBPs in odor recognition, and can be expanded to the identification of other ligands for OBPs of Anopheles and other medically important insects. 相似文献
99.
Wegner LH Stefano G Shabala L Rossi M Mancuso S Shabala S 《Plant, cell & environment》2011,34(5):859-869
Early events in NaCl-induced root ion and water transport were investigated in maize (Zea mays L) roots using a range of microelectrode and imaging techniques. Addition of 100 mm NaCl to the bath resulted in an exponential drop in root xylem pressure, rapid depolarization of trans-root potential and a transient drop in xylem K(+) activity (A(K+) ) within ~1 min after stress onset. At this time, no detectable amounts of Na(+) were released into the xylem vessels. The observed drop in A(K+) was unexpected, given the fact that application of the physiologically relevant concentrations of Na(+) to isolated stele has caused rapid plasma membrane depolarization and a subsequent K(+) efflux from the stelar tissues. This controversy was explained by the difference in kinetics of NaCl-induced depolarization between cortical and stelar cells. As root cortical cells are first to be depolarized and lose K(+) to the environment, this is associated with some K(+) shift from the stelar symplast to the cortex, resulting in K(+) being transiently removed from the xylem. Once Na(+) is loaded into the xylem (between 1 and 5 min of root exposure to NaCl), stelar cells become more depolarized, and a gradual recovery in A(K+) occurs. 相似文献
100.
Fungi of the genus Fusarium are important plant pathogens and contaminants of cereal grains producing different types of mycotoxins. Enniatins are a group of mycotoxins with ionophoric properties frequently detected in North European grains. Within the Fusarium complex responsible for grain infection, Fusarium avenaceum, Fusarium poae and Fusarium tricinctum are the most potential enniatins producers. This study presents the development of two quantitative TaqMan MGB (Minor Groove Binder) assays for the specific quantification of F. avenaceum/F. tricinctum and F. poae esyn1 genotypes, respectively. Two sets of genotype-specific primers/probes were designed on the basis of esyn1 gene homologues encoding multifunctional enzyme enniatin synthetase. The specificity of the assays developed has been tested successfully on 111 Fusarium isolates from different geographical origins. The detection limits for F. avenaceum/F. tricinctum esyn1 genotype and F. poae genotype were 19 and 0.3?pg, respectively. The application of the assays developed on asymptomatic wheat grain samples revealed significant positive correlations between the enniatins levels and the amount of F. avenaceum/F. tricinctum esyn1 genotype (R=0.61) and F. poae esyn1 genotype (R=0.42). 相似文献