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111.
Calcium and S100B Regulation of p53-Dependent Cell Growth Arrest and Apoptosis 总被引:9,自引:1,他引:9 下载免费PDF全文
Christian Scotto Jean Christophe Deloulme Denis Rousseau Edmond Chambaz Jacques Baudier 《Molecular and cellular biology》1998,18(7):4272-4281
In glial C6 cells constitutively expressing wild-type p53, synthesis of the calcium-binding protein S100B is associated with cell density-dependent inhibition of growth and apoptosis in response to UV irradiation. A functional interaction between S100B and p53 was first demonstrated in p53-negative mouse embryo fibroblasts (MEF cells) by sequential transfection with the S100B and the temperature-sensitive p53Val135 genes. We show that in MEF cells expressing a low level of p53Val135, S100B cooperates with p53Val135 in triggering calcium-dependent cell growth arrest and cell death in response to UV irradiation at the nonpermissive temperature (37.5°C). Calcium-dependent growth arrest of MEF cells expressing S100B correlates with specific nuclear accumulation of the wild-type p53Val135 conformational species. S100B modulation of wild-type p53Val135 nuclear translocation and functions was confirmed with the rat embryo fibroblast (REF) cell line clone 6, which is transformed by oncogenic Ha-ras and overexpression of p53Val135. Ectopic expression of S100B in clone 6 cells restores contact inhibition of growth at 37.5°C, which also correlates with nuclear accumulation of the wild-type p53Val135 conformational species. Moreover, a calcium ionophore mediates a reversible G1 arrest in S100B-expressing REF (S100B-REF) cells at 37.5°C that is phenotypically indistinguishable from p53-mediated G1 arrest at the permissive temperature (32°C). S100B-REF cells proceeding from G1 underwent apoptosis in response to UV irradiation. Our data support a model in which calcium signaling and S100B cooperate with the p53 pathways of cell growth inhibition and apoptosis. 相似文献
112.
Apical membrane antigen 1: a malaria vaccine candidate in review 总被引:3,自引:0,他引:3
Apical membrane antigen 1 (AMA1) is a micronemal protein of apicomplexan parasites that appears to be essential during the invasion of host cells. Immune responses to Plasmodium AMA1 can have profound parasite-inhibitory effects, both as measured in vitro and in animal challenge models, suggesting AMA1 as a potential vaccine component. However, AMA1 is polymorphic, probably as a result of immune selection operating on an important target of naturally occurring immunity. The current understanding of AMA1 will be presented, particularly in relation to the vaccine potential of AMA1 and the approaches being taken towards clinical development. 相似文献
113.
Xiaohui Tang Alain M. Jonas Bernard Nysten Sophie Demoustier-Champagne Franoise Blondeau Pierre-Paul Prvot Rmi Pampin Edmond Godfroid Benjamin Iiguez Jean-Pierre Colinge Jean-Pierre Raskin Denis Flandre Vincent Bayot 《Biosensors & bioelectronics》2009,24(12):3531-3537
A new protein sensor is demonstrated by replacing the gate of a metal oxide semiconductor field effect transistor (MOSFET) with a nano-interdigitated array (nIDA). The sensor is able to detect the binding reaction of a typical antibody Ixodes ricinus immunosuppressor (anti-Iris) protein at a concentration lower than 1 ng/ml. The sensor exhibits a high selectivity and reproducible specific detection. We provide a simple model that describes the behavior of the sensor and explains the origin of its high sensitivity. The simulated and experimental results indicate that the drain current of nIDA-gate MOSFET sensor is significantly increased with the successive binding of the thiol layer, Iris and anti-Iris protein layers. It is found that the sensor detection limit can be improved by well optimizing the geometrical parameters of nIDA-gate MOSFET. This nanobiosensor, with real-time and label-free capabilities, can easily be used for the detection of other proteins, DNA, virus and cancer markers. Moreover, an on-chip associated electronics nearby the sensor can be integrated since its fabrication is compatible with complementary metal oxide semiconductor (CMOS) technology. 相似文献
114.
The Deinococcus radiodurans SMC protein is dispensable for cell viability yet plays a role in DNA folding 总被引:1,自引:0,他引:1
Claire Bouthier de la Tour Magali Toueille Edmond Jolivet Hong-Ha Nguyen Pascale Servant Françoise Vannier Suzanne Sommer 《Extremophiles : life under extreme conditions》2009,13(5):827-837
Deinococcus radiodurans contains a highly condensed nucleoid that remains to be unaltered following the exposure to high doses of γ-irradiation.
Proteins belonging to the structural maintenance of chromosome protein (SMC) family are present in all organisms and were
shown to be involved in chromosome condensation, pairing, and/or segregation. Here, we have inactivated the smc gene in the radioresistant bacterium D. radiodurans, and, unexpectedly, found that smc null mutants showed no discernible phenotype except an increased sensitivity to gyrase inhibitors suggesting a role of SMC
in DNA folding. A defect in the SMC-like SbcC protein exacerbated the sensitivity to gyrase inhibitors of cells devoid of
SMC. We also showed that the D. radiodurans SMC protein forms discrete foci at the periphery of the nucleoid suggesting that SMC could locally condense DNA. The phenotype
of smc null mutant leads us to speculate that other, not yet identified, proteins drive the compact organization of the D. radiodurans nucleoid. 相似文献
115.
Ane Marcos-Carcavilla Carole Moreno Magdalena Serrano Pascal Laurent Edmond P. Cribiu Olivier Andréoletti Julien Ruesche Jean-Louis Weisbecker Jorge H. Calvo Katayoun Moazami-Goudarzi 《Cell stress & chaperones》2010,15(4):343-349
Susceptibility to scrapie is mainly controlled by point mutations at the PRNP locus. However, additional quantitative trait loci (QTL) have been identified across the genome including a region in OAR18.
The gene which encodes the inducible form of the cytoplasmic Hsp90 chaperone (HSP90AA1) maps within this region and seems to be associated with the resistance/susceptibility to scrapie in sheep. Here, we have
analyzed several polymorphisms which were previously described in the ovine HSP90AA1 5′ flanking region and in intron 10 in two naturally scrapie infected Romanov sheep populations. First, we have studied 58
ARQ/VRQ animals pertaining to the sire family where the QTL influencing scrapie incubation period in OAR18 was detected. We
have found a significant association between polymorphisms localized at −660 and −528 in the HSP90AA1 5′ flanking region and the scrapie incubation period. These two polymorphisms have also been studied in a second sample constituted
by 62 VRQ/VRQ sheep showing an extreme incubation period. Results are concordant with the first dataset. Finally, we have
studied the HSP90AA1 expression in scrapie and control animals (N = 41) with different HSP90AA1 genotypes by real time PCR on blood samples. The HSP90AA1 expression rate was equivalent in CC−600AA−528 and CG−600AG−528 scrapie resistant animals (ARR/ARR) and was higher in their CC−600AA−528 than in their CG−600AG−528 scrapie susceptible counterparts (VRQ/VRQ). Our results support the hypothesis that the ovine HSP90AA1 gene acts as a modulator of scrapie susceptibility, contributing to the observed differences in the incubation period of
scrapie infected animals with the same PRNP genotype. 相似文献
116.
Minhas GS Pilch DS Kerrigan JE LaVoie EJ Rice JE 《Bioorganic & medicinal chemistry letters》2006,16(15):3891-3895
The synthesis of 24-membered macrocycles containing four, six, and seven oxazole moieties is described. Selected compounds were evaluated for their ability to specifically bind and stabilize G-quadruplex DNA and for cytotoxic activity. An unexpected oxidative cleavage reaction afforded a macrocyclic imide that was also evaluated for G-quadruplex stabilizing and cytotoxic activity. 相似文献
117.
There is increasing interest in multi-allele vaccines to overcome strain-specificity against polymorphic vaccine targets such as Apical Membrane Antigen 1 (AMA1). These have been shown to induce broad inhibitory antibodies in vitro and formed the basis for the design of three Diversity-Covering (DiCo) proteins with similar immunological effects. The antibodies produced are to epitopes that are shared between vaccine alleles and theoretically, increasing the number of component AMA1 alleles is expected to broaden the antibody response. A plateau effect could however impose a limit on the number of alleles needed to achieve the broadest specificity. Moreover, production cost and the vaccine formulation process would limit the number of component alleles. In this paper, we compare rabbit antibody responses elicited with multi-allele vaccines incorporating seven (three DiCos and four natural AMA1 alleles) and three (DiCo mix) antigens for gains in broadened specificity. We also investigate the effect of three adjuvant platforms on antigen specificity and antibody functionality. Our data confirms a broadened response after immunisation with DiCo mix in all three adjuvants. Higher antibody titres were elicited with either CoVaccine HT™ or Montanide ISA 51, resulting in similar in vitro inhibition (65–82%) of five out of six culture-adapted P. falciparum strains. The antigen binding specificities of elicited antibodies were also similar and independent of the adjuvant used or the number of vaccine component alleles. Thus neither the four extra antigens nor adjuvant had any observable benefits with respect to specificity broadening, although adjuvant choice influenced the absolute antibody levels and thus the extent of parasite inhibition. Our data confirms the feasibility and potential of multi-allele PfAMA1 formulations, and highlights the need for adjuvants with improved antibody potentiation properties for AMA1-based vaccines. 相似文献
118.
Gaudioso C Carlier E Youssouf F Clare JJ Debanne D Alcaraz G 《Biochemical and biophysical research communications》2011,411(2):329-334
Mutations in the neuronal Nav1.1 voltage-gated sodium channel are responsible for mild to severe epileptic syndromes. The ubiquitous calcium sensor calmodulin (CaM) bound to rat brain Nav1.1 and to the human Nav1.1 channel expressed by a stably transfected HEK-293 cell line. The C-terminal region of the channel, as a fusion protein or in the yeast two-hybrid system, interacted with CaM via a consensus C-terminal motif, the IQ domain. Patch clamp experiments on HEK1.1 cells showed that CaM overexpression increased peak current in a calcium-dependent way. CaM had no effect on the voltage-dependence of fast inactivation, and accelerated the inactivation kinetics. Elevating Ca++ depolarized the voltage-dependence of fast inactivation and slowed down the fast inactivation kinetics, and for high concentrations this effect competed with the acceleration induced by CaM alone. Similarly, the depolarizing action of calcium antagonized the hyperpolarizing shift of the voltage-dependence of activation due to CaM overexpression. Fluorescence spectroscopy measurements suggested that Ca++ could bind the Nav1.1 C-terminal region with micromolar affinity. 相似文献
119.
Operant and maze tasks in mice are limited by the small number of trials possible in a session before mice lose motivation. We hypothesized that by manipulating reward size and session length, motivation, and hence performance, would be maintained in an automated T-maze. We predicted that larger rewards and shorter sessions would improve acquisition; and smaller rewards and shorter sessions would maintain higher and less variable performance. Eighteen C57BL/6J mice (9 per sex) acquired (criterion 8/10 correct) and performed a spatial discrimination, with one of 3 reward sizes (.02, .04, or .08 g) and one of 3 session schedules (15, 30, or 45 min sessions). Each mouse had a total of 360 min of access to the maze per night, for two nights, and averaged 190 trials. Analysis used split-plot GLM with contrasts testing for linear effects. Acquisition of the discrimination was unaffected by reward size or session length/interval. After-criterion average performance improved as reward size decreased. After-criterion variability in performance was also affected. Variability increased as reward size increased. Session length/interval did not affect any outcome. We conclude that an automated maze, with suitable reward sizes, can sustain performance with low variability, at 5-10 times faster than traditional methods. 相似文献
120.
Tjeerd-Pieter van Staa Martin Gulliford Edmond S.-W. Ng Ben Goldacre Liam Smeeth 《PloS one》2014,9(10)