全文获取类型
收费全文 | 798篇 |
免费 | 61篇 |
出版年
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 4篇 |
2019年 | 17篇 |
2018年 | 11篇 |
2017年 | 10篇 |
2016年 | 18篇 |
2015年 | 40篇 |
2014年 | 39篇 |
2013年 | 44篇 |
2012年 | 64篇 |
2011年 | 53篇 |
2010年 | 56篇 |
2009年 | 32篇 |
2008年 | 53篇 |
2007年 | 55篇 |
2006年 | 45篇 |
2005年 | 57篇 |
2004年 | 42篇 |
2003年 | 43篇 |
2002年 | 33篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 20篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1928年 | 2篇 |
1927年 | 2篇 |
1925年 | 1篇 |
排序方式: 共有859条查询结果,搜索用时 15 毫秒
51.
Absence of transitive and systemic pathways allows cell-specific and isoform-specific RNAi in Drosophila 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《RNA (New York, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roignant JY Carré C Mugat B Szymczak D Lepesant JA Antoniewski C 《RNA (New York, N.Y.)》2003,9(3):299-308
RNA interference (RNAi) designates the multistep process by which double-stranded RNA induces the silencing of homologous endogenous genes. Some aspects of RNAi appear to be conserved throughout evolution, including the processing of trigger dsRNAs into small 21-23-bp siRNAs and their use to guide the degradation of complementary mRNAs. Two remarkable features of RNAi were uncovered in plants and Caenorhabditid elegans. First, RNA-dependent RNA polymerase activities allow the synthesis of siRNA complementary to sequences upstream of or downstream from the initial trigger region in the target mRNA, leading to a transitive RNAi with sequences that had not been initially targeted. Secondly, systemic RNAi may cause the targeting of gene silencing in one tissue to spread to other tissues. Using transgenes expressing dsRNA, we investigated whether transitive and systemic RNAi occur in DROSOPHILA: DsRNA-producing transgenes targeted RNAi to specific regions of alternative mRNA species of one gene without transitive effect directed to sequences downstream from or upstream of the initial trigger region. Moreover, specific expression of a dsRNA, using either cell-specific GAL4 drivers or random clonal activation of a GAL4 driver, mediated a cell-autonomous RNAi. Together, our results provide evidence that transitive and systemic aspects of RNAi are not conserved in Drosophila and demonstrate that dsRNA-producing transgenes allow powerful reverse genetic approaches to be conducted in this model organism, by knocking down gene functions at the resolution of a single-cell type and of a single isoform. 相似文献
52.
Pseudolernentoma, a new chondracanthid genus was proposed to accommodate Pseudolernentoma brasiliensis n. g., n. sp., parasitic on the pink cusk-eel Genypterus brasiliensis Regan, from off the coast of Rio de Janeiro, Brazil. The new genus can be differentiated from the other genera of the Chondracanthidae by the presence of an inflated head with lateral expansions and anteroventral bifurcate processes on the trunk. 相似文献
53.
54.
Martha P. Brown Dimitri Toptygin K. B. Lee Theresa Animashaun R. C. Hughes Y. C. Lee Ludwig Brand 《The protein journal》1998,17(2):149-159
The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J. 11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (λex = 295 nm, λem = 350 nm) decay is complex and can be described by four decay times with the following values: τ1 = 7.4nsec, α1 = 0.22; τ2 = 2.9 nsec, α2 = 0.25; τ3 = l.0 nsec, α3 = 0.34; τ4 = 0.2 nsec, α4 = 0.18. The addition of a biantennary glycopeptide $\begin{array}{*{20}c} {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 6)\neg } \\ {Man\beta (1 \to 4)GlcNAC\beta (1 \to 4)GlcAc\beta (1 \to )\begin{array}{*{20}c} {Glu - Nh_2 } \\ | \\ {Asn} \\ | \\ {COOH} \\ \end{array} } \\ {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 3)} \\ \end{array} $ to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×105 M?1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein. 相似文献
55.
56.
Martha P. Brown Dimitri Toptygin K. B. Lee Theresa Animashaun R. C. Hughes Y. C. Lee Ludwig Brand 《Journal of Protein Chemistry》1998,17(2):149-159
The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J.
11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (ex = 295 nm, em = 350 nm) decay is complex and can be described by four decay times with the following values: 1 = 7.4nsec, 1 = 0.22; 2 = 2.9 nsec, 2 = 0.25; 3 = l.0 nsec, 3 = 0.34; 4 = 0.2 nsec, 4 = 0.18. The addition of a biantennary glycopeptide
to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×105 M–1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein. 相似文献
57.
Stephane Fournier Patrick Taffé Dragana Radovanovic Erik Von Elm Beata Morawiec Jean-Christophe Stauffer Paul Erne Ahmed Beggah Pierre Monney Patrizio Pascale Juan-Fernando Iglesias Eric Eeckhout Olivier Muller 《PloS one》2015,10(3)
Background
Different studies have shown circadian variation of ischemic burden among patients with ST-Elevation Myocardial Infarction (STEMI), but with controversial results. The aim of this study was to analyze circadian variation of myocardial infarction size and in-hospital mortality in a large multicenter registry.Methods
This retrospective, registry-based study was based on data from AMIS Plus, a large multicenter Swiss registry of patients who suffered myocardial infarction between 1999 and 2013. Peak creatine kinase (CK) was used as a proxy measure for myocardial infarction size. Associations between peak CK, in-hospital mortality, and the time of day at symptom onset were modelled using polynomial-harmonic regression methods.Results
6,223 STEMI patients were admitted to 82 acute-care hospitals in Switzerland and treated with primary angioplasty within six hours of symptom onset. Only the 24-hour harmonic was significantly associated with peak CK (p = 0.0001). The maximum average peak CK value (2,315 U/L) was for patients with symptom onset at 23:00, whereas the minimum average (2,017 U/L) was for onset at 11:00. The amplitude of variation was 298 U/L. In addition, no correlation was observed between ischemic time and circadian peak CK variation. Of the 6,223 patients, 223 (3.58%) died during index hospitalization. Remarkably, only the 24-hour harmonic was significantly associated with in-hospital mortality. The risk of death from STEMI was highest for patients with symptom onset at 00:00 and lowest for those with onset at 12:00.Discussion
As a part of this first large study of STEMI patients treated with primary angioplasty in Swiss hospitals, investigations confirmed a circadian pattern to both peak CK and in-hospital mortality which were independent of total ischemic time. Accordingly, this study proposes that symptom onset time be incorporated as a prognosis factor in patients with myocardial infarction. 相似文献58.
Marc Alain Züst Patrizio Colella Thomas Peter Reber Patrik Vuilleumier Martinus Hauf Simon Ruch Katharina Henke 《PloS one》2015,10(3)
Recent evidence suggests that humans can form and later retrieve new semantic relations unconsciously by way of hippocampus—the key structure also recruited for conscious relational (episodic) memory. If the hippocampus subserves both conscious and unconscious relational encoding/retrieval, one would expect the hippocampus to be place of unconscious-conscious interactions during memory retrieval. We tested this hypothesis in an fMRI experiment probing the interaction between the unconscious and conscious retrieval of face-associated information. For the establishment of unconscious relational memories, we presented subliminal (masked) combinations of unfamiliar faces and written occupations (“actor” or “politician”). At test, we presented the former subliminal faces, but now supraliminally, as cues for the reactivation of the unconsciously associated occupations. We hypothesized that unconscious reactivation of the associated occupation—actor or politician—would facilitate or inhibit the subsequent conscious retrieval of a celebrity’s occupation, which was also actor or politician. Depending on whether the reactivated unconscious occupation was congruent or incongruent to the celebrity’s occupation, we expected either quicker or delayed conscious retrieval process. Conscious retrieval was quicker in the congruent relative to a neutral baseline condition but not delayed in the incongruent condition. fMRI data collected during subliminal face-occupation encoding confirmed previous evidence that the hippocampus was interacting with neocortical storage sites of semantic knowledge to support relational encoding. fMRI data collected at test revealed that the facilitated conscious retrieval was paralleled by deactivations in the hippocampus and neocortical storage sites of semantic knowledge. We assume that the unconscious reactivation has pre-activated overlapping relational representations in the hippocampus reducing the neural effort for conscious retrieval. This finding supports the notion of synergistic interactions between conscious and unconscious relational memories in a common, cohesive hippocampal-neocortical memory space. 相似文献
59.
Michel Guipponi Federico A. Santoni Vincent Setola Corinne Gehrig Maud Rotharmel Macarena Cuenca Olivier Guillin Dimitris Dikeos Georgios Georgantopoulos George Papadimitriou Logos Curtis Alexandre Méary Franck Schürhoff Stéphane Jamain Dimitri Avramopoulos Marion Leboyer Dan Rujescu Ann Pulver Dominique Campion David P. Siderovski Stylianos E. Antonarakis 《PloS one》2015,10(10)
60.