全文获取类型
收费全文 | 192篇 |
免费 | 12篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 15篇 |
2013年 | 11篇 |
2012年 | 17篇 |
2011年 | 15篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有204条查询结果,搜索用时 15 毫秒
81.
Yawn contagion is not restricted to humans and has also been reported for several non-human animal species, including chimpanzees (Pan troglodytes). Contagious yawning may lead to synchronisation of behaviour. However, the function of contagious yawning is relatively understudied. In this study, we investigated the function of contagious yawning by focusing on two types of signal providers: close social associates and leaders. We provided a captive chimpanzee colony with videos of all individuals of their own group that were either yawning, or at rest. Consistent with other studies, we demonstrated that yawning is contagious for chimpanzees, yet we did not find any effect of relationship quality on yawn contagion. However, we show that yawn contagion is significantly higher when the video model is a yawning male than when the video model was a yawning female, and that this effect is most apparent among males. As males are dominant in chimpanzee societies, male signals may be more relevant to the rest of the group than female signals. Moreover, since chimpanzees form male-bonded societies, male signals are especially relevant for other males. Therefore, we suggest that the sex-differences of yawning contagion among chimpanzees reflect the function of yawning in the synchronisation of behaviour. 相似文献
82.
Characterisation of a human Y chromosome repeated sequence and related sequences in higher primates 总被引:33,自引:0,他引:33
The human Y chromosome carries 2000 copies of a tandemly repeated sequence, 2.47 kb long, which constitutes about 20% of the DNA of this chromosome. These sequences are localised on the tip of the long arm of the Y chromosome. Related sequences are present in DNA of females with a related but distinguishable restriction pattern. These autosomal sequences are distributed in tandem arrays on a number of autosomes. Related sequences are also present in gorilla and chimpanzee. In gorilla they resemble the human sequences in their restriction map but are not found on the Y chromosome whereas in chimpanzee the related sequences behave as a dispersed repeat. Changes in the level of methylation of this sequence in different tissues of human males can be detected with the lowest levels found in sperm and placental DNA. 相似文献
83.
84.
Sbroggiò M Ferretti R Percivalle E Gutkowska M Zylicz A Michowski W Kuznicki J Accornero F Pacchioni B Lanfranchi G Hamm J Turco E Silengo L Tarone G Brancaccio M 《FEBS letters》2008,582(13):1788-1794
Melusin is a mammalian muscle specific CHORD containing protein capable of activating signal transduction pathways leading to cardiomyocytes hypertrophy in response to mechanical stress. To define melusin function we searched for molecular partners possibly involved in melusin dependent signal transduction. Here we show that melusin and heat shock proteins are co-regulated. Moreover, melusin directly binds to Hsp90, a ubiquitous chaperone involved in regulating several signaling pathways. In addition, melusin interacts with Sgt1, an Hsp90 binding molecule. Melusin does not behave as an Hsp90 substrate but rather as a chaperone capable to protect citrate synthase from heat induced aggregation. These results describe melusin as a new component of the Hsp90 chaperone machinery. 相似文献
85.
86.
Birgit Knebel Stefan Lehr Onno E. Janssen Susanne Hahn Sylvia Jacob Ulrike Nitzgen Dirk Müller-Wieland Jorg Kotzka 《Molecular biology reports》2017,44(1):51-61
Polygenic diseases with a broad phenotypic spectrum, such as polycystic ovary syndrome (PCOS), present a particular challenge in terms of identifying the underlying genetic mechanisms, nevertheless genetic variants have impact on the individual phenotype. We aimed to determine if next to genetic variations like SNPs further mechanisms might play a role in the pathogenesis of PCOS. We examined the effect of copy-number variations (CNVs) on metabolic phenotypes in PCOS. The intragenic rs1244979, rs2815752 in NEGR1 gene, and rs780094 in GCKR gene were genotyped and CNVs were determined by droplet digital polymerase chain reaction (ddPCR) in PCOS patients (n?=?153) and controls without metabolic syndrome (n?=?142). The study indicated that SNPs are not associated with the pathogenesis of PCOS but affect metabolic phenotypes. The CNVs investigated show a lower variability in PCOS than in CON. Furthermore, we provided direct evidence that the copy number, but not the genotype of the CNV in the genomic regions of rs780094(GCKR) is associated with low level of high-density lipoprotein cholesterol in PCOS. This study supports the hypothesis that not only genetic variants, but also CNVs in metabolically relevant genes, have an effect on metabolic phenotypes in our group of PCOS patients. 相似文献
87.
Kathrin Schliicking Kai H. Edel Maria M. Drerupa Philipp Koster Christian Eckert Leonie Steinhorst Rainer Waadt Oliver Batistic Jorg Kudla 《植物生理学报》2013,(6):1814-1829
Transient and stable expression of transgenes is central to many investigations in plant biology research. Chemical regulation of expression can circumvent problems of plant lethality caused by constitutive overexpression or allow inducible knock (out/down) approaches. Several chemically inducible or repressible systems have been described and successfully applied. However, cloning and application-specific modification of most available inducible expression systems have been limited and remained complicated due to restricted cloning options. Here we describe a new set of 57 vectors that enable transgene expression in transiently or stably transformed cells. All vectors harbor a synthetically optimized XVE expression cassette, allowing I~-estradiol mediated protein expression. Plasmids are equipped with the reporter genes GUS, GFP, mCherry, or with HA and Strepll epitope tags and harbor an optimized multiple cloning site for flexible and simple clon- ing strategies. Moreover, the vector design allows simple substitution of the driving promoter to achieve tissue-specificity or to modulate expression ranges of inducible transgene expression. We report details of the kinetics and dose-dependence of expression induction in Arabidopsis leaf mesophyll protoplasts, transiently transformed Nicotiana benthamiana leaves, and stably transformed Arabidopsis plants. Using these vectors, we investigated the influence of CBL (Calcineurin B-like) protein expression on the subcellular localization of CIPKs (Calcineurin B-like interacting protein kinases). These analyses uncovered that induced co-expression of CBL3 is fully sufficient for dynamic translocation of CIPK5 from the cytoplasm to the tonoplast. Thus, the vector system presented here facilitates a broad range of research applications. 相似文献
88.
Male rank,reproductive behavior,and reproductive success in free-ranging rhesus macaques 总被引:2,自引:0,他引:2
John D. Berard Peter Nürnberg Jorg T. Epplen Jorg Schmidtke 《Primates; journal of primatology》1993,34(4):481-489
Paternity assessment through DNA fingerprinting by synthetic oligonucleotide probes was applied to one birth cohort in a social
group of free-ranging rhesus macaques (Macaca mulatta) on Cayo Santiago. The 11 group males and 9 males from other groups were observed mating with the females. Paternity was
determined for 11 of the 15 infants. Male dominance rank was not associated with reproductive success. High-ranking resident
males (N=5) sired 27% of the infants born during a one-year study. Four of the 11 infants of known paternity were sired by males of
other social groups. The four infants of unknown paternity were sired either by males not observed mating with the females
or the low-ranking male who was not fingerprinted. Male dominance rank was not associated with reproductive activity during
conception cycles. These results suggest that the effect of rank on male reproductive success is not a predictable correlation,
but a conditional probability. 相似文献
89.
Superoxide Dismutase Activity, Oxidative Damage, and Mitochondrial Energy Metabolism in Familial and Sporadic Amyotrophic Lateral Sclerosis 总被引:23,自引:2,他引:21
Allen C. Bowling Jorg B. Schulz Robert H. Brown Jr. M. Flint Beal 《Journal of neurochemistry》1993,61(6):2322-2325
The cause of neuronal death in amyotrophic lateral sclerosis (ALS) is unknown. Recently, it was found that some patients with autosomal-dominant familial ALS (FALS) have point mutations in the gene that encodes Cu/Zn superoxide dismutase (SOD1). In this study of postmortem brain tissue, we examined SOD activity and quantified protein carbonyl groups, a marker of oxidative damage, in samples of frontal cortex (Brodmann area 6) from 10 control patients, three FALS patients with known SOD1 mutations (FALS-1), one autosomal-dominant FALS patient with no identifiable SOD1 mutations (FALS-0), and 11 sporadic ALS (SALS) patients. Also, we determined the activities of components of the electron transport chain (complexes I, II-III, and IV) in these samples. The cytosolic SOD activity, which is primarily SOD1 activity, was reduced by 38.8% (p < 0.05) in the FALS-1 patients and not significantly altered in the SALS patients or the FALS-0 patient relative to the control patients. The mitochondrial SOD activity, which is primarily SOD2 activity, was not significantly altered in the FALS-1, FALS-0, or SALS patients. The protein carbonyl content was elevated by 84.8% (p < 0.01) in the SALS patients relative to the control patients. Finally, the complex I activity was increased by 55.3% (p < 0.001) in the FALS-1 patients relative to the control patients. These results from cortical tissue demonstrate that SOD1 activity is reduced and complex I activity is increased in FALS-1 patients and that oxidative damage to proteins is increased in SALS patients. 相似文献
90.
Tomizawa Ken-ichi; Stockhaus Jorg; Chua Nam-Hai; Furuya Masaki 《Plant & cell physiology》1995,36(3):511-516
A cDNA (PHYA) for the phytochrome A apoprotein (PHYA) of riceand three mutated sequences (phyA S/A, the first ten serineresidues in the N-terminal domain of PHYA were changed to alanineresidues; phyA ND, the first 80 N-terminal amino acids weredeleted; phyA CD, the amino acids of the C-terminal domain from689 to 1,128 were deleted) were expressed in yeast, and thewild-type and mutant apophytochromes were allowed to combinein vitro with the chromophore phycocyanobilin (PCB). The PCB-attachedproduct of phyA S/A gave very similar spectrophotometric peaksto the PhAfr and PhyAfr forms of wild-type product. By contrast,the peak of the product of phyA CD in the Pfr form was significantlyshifted towards a shorter wavelength, an indication that, whereasthe C-terminal domain is not crucial for the PCB attachment,it greatly influences the absorption maximum of PhyAfr. Therate of 50% reversion from PhyAfr to PhAr in darkness was 3h at 27°C with all of the samples, showing that the S/Aand CD mutations did not affect this property. No photoreversibilitywas detected with the product of phyA ND. Gel-filtration analysisof the wild-type PHYA and the product of phyA S/A showed thatthe apparent molecular mass of each was 330 kDa, suggestingthat both exists as dimers in solution.
4Present address: Institut für Entwicklungs- und Molekularbiologieder Pflanzen, Heinrich-Heine-Universität-Düsseldorf,Universitätsstr. 1, 40225 Düsseldorf, Germany 相似文献