全文获取类型
收费全文 | 306篇 |
免费 | 26篇 |
国内免费 | 1篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 16篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1964年 | 3篇 |
1953年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有333条查询结果,搜索用时 31 毫秒
101.
Mutual information (I) provides a robust measure of genetic differentiation for the purposes of estimating dispersal between populations. At present, however, there is little predictive theory for I. The growing importance in population biology of analyses of single-nucleotide and other single-feature polymorphisms (SFPs) is a potent reason for developing an analytic theory for I with respect to a single locus. This study represents a first step towards such a theory. We present theoretical predictions of I between two populations with respect to a single haploid biallelic locus. Dynamical and steady-state forecasts of I are derived from a Wright-Fisher model with symmetrical mutation between alleles and symmetrical dispersal between populations. Analytical predictions of a simple Taylor approximation to I are in good agreement with numerical simulations of I and with data on I from SFP analyses of dispersal experiments on Drosophila fly populations. The theory presented here also provides a basis for the future inclusion of selection effects and extension to multiallelic loci. 相似文献
102.
103.
104.
W. A. Dewar 《BMJ (Clinical research ed.)》1953,1(4823):1333-1334
105.
Gus Koerbin Jillian R Tate Julie Ryan Graham RD Jones Ken A Sikaris David Kanowski Maxine Reed Janice Gill George Koumantakis Tina Yen Andrew St John Peter E Hickman Aaron Simpson Peter Graham 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2014,35(4):203-211
Harmonisation of reference intervals for routine general chemistry analytes has been a goal for many years. Analytical bias may prevent this harmonisation. To determine if analytical bias is present when comparing methods, the use of commutable samples, or samples that have the same properties as the clinical samples routinely analysed, should be used as reference samples to eliminate the possibility of matrix effect. The use of commutable samples has improved the identification of unacceptable analytical performance in the Netherlands and Spain. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has undertaken a pilot study using commutable samples in an attempt to determine not only country specific reference intervals but to make them comparable between countries. Australia and New Zealand, through the Australasian Association of Clinical Biochemists (AACB), have also undertaken an assessment of analytical bias using commutable samples and determined that of the 27 general chemistry analytes studied, 19 showed sufficiently small between method biases as to not prevent harmonisation of reference intervals. Application of evidence based approaches including the determination of analytical bias using commutable material is necessary when seeking to harmonise reference intervals. 相似文献
106.
People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition. 相似文献
107.
The pathogenesis of coeliac disease 总被引:2,自引:0,他引:2
Dewar D Pereira SP Ciclitira PJ 《The international journal of biochemistry & cell biology》2004,36(1):17-24
Coeliac disease is a chronic enteropathy caused by intolerance to gluten proteins. The true prevalence of this condition is greater than previously thought, with increasing numbers of 'silent' cases being diagnosed. Untreated coeliac disease is associated with significant morbidity and increased mortality. There have been a number of advances in our understanding of the pathogenesis of coeliac disease, in particular the mechanisms whereby gluten epitopes are processed, become modified by tissue transglutaminase (tTG) and then interact with HLA restricted T cells. An improved understanding of the immune response to gluten is likely to lead to the development of novel strategies for the treatment of coeliac disease. 相似文献
108.
Plant root distributions and nitrogen uptake predicted by a hypothesis of optimal root foraging 总被引:1,自引:0,他引:1
RE McMurtrie CM Iversen RC Dewar BE Medlyn T Näsholm DA Pepper RJ Norby 《Ecology and evolution》2012,2(6):1235-1250
CO(2)-enrichment experiments consistently show that rooting depth increases when trees are grown at elevated CO(2) (eCO(2)), leading in some experiments to increased capture of available soil nitrogen (N) from deeper soil. However, the link between N uptake and root distributions remains poorly represented in forest ecosystem and global land-surface models. Here, this link is modeled and analyzed using a new optimization hypothesis (MaxNup) for root foraging in relation to the spatial variability of soil N, according to which a given total root mass is distributed vertically in order to maximize annual N uptake. MaxNup leads to analytical predictions for the optimal vertical profile of root biomass, maximum rooting depth, and N-uptake fraction (i.e., the proportion of plant-available soil N taken up annually by roots). We use these predictions to gain new insight into the behavior of the N-uptake fraction in trees growing at the Oak Ridge National Laboratory free-air CO(2)-enrichment experiment. We also compare MaxNup with empirical equations previously fitted to root-distribution data from all the world's plant biomes, and find that the empirical equations underestimate the capacity of root systems to take up N. 相似文献
109.
Satou Y Mineta K Ogasawara M Sasakura Y Shoguchi E Ueno K Yamada L Matsumoto J Wasserscheid J Dewar K Wiley GB Macmil SL Roe BA Zeller RW Hastings KE Lemaire P Lindquist E Endo T Hotta K Inaba K 《Genome biology》2008,9(10):R152-11
Background
The draft genome sequence of the ascidian Ciona intestinalis, along with associated gene models, has been a valuable research resource. However, recently accumulated expressed sequence tag (EST)/cDNA data have revealed numerous inconsistencies with the gene models due in part to intrinsic limitations in gene prediction programs and in part to the fragmented nature of the assembly.Results
We have prepared a less-fragmented assembly on the basis of scaffold-joining guided by paired-end EST and bacterial artificial chromosome (BAC) sequences, and BAC chromosomal in situ hybridization data. The new assembly (115.2 Mb) is similar in length to the initial assembly (116.7 Mb) but contains 1,272 (approximately 50%) fewer scaffolds. The largest scaffold in the new assembly incorporates 95 initial-assembly scaffolds. In conjunction with the new assembly, we have prepared a greatly improved global gene model set strictly correlated with the extensive currently available EST data. The total gene number (15,254) is similar to that of the initial set (15,582), but the new set includes 3,330 models at genomic sites where none were present in the initial set, and 1,779 models that represent fusions of multiple previously incomplete models. In approximately half, 5'-ends were precisely mapped using 5'-full-length ESTs, an important refinement even in otherwise unchanged models.Conclusion
Using these new resources, we identify a population of non-canonical (non-GT-AG) introns and also find that approximately 20% of Ciona genes reside in operons and that operons contain a high proportion of single-exon genes. Thus, the present dataset provides an opportunity to analyze the Ciona genome much more precisely than ever. 相似文献110.
Advaitha Iyer Moritz Niemann Mauro Serricchio Caroline E. Dewar Silke Oeljeklaus Luce Farine Bettina Warscheid Andr Schneider Peter Bütikofer 《PLoS pathogens》2022,18(5)
The endoplasmic reticulum membrane complex (EMC) is a versatile complex that plays a key role in membrane protein biogenesis in the ER. Deletion of the complex has wide-ranging consequences including ER stress, disturbance in lipid transport and organelle tethering, among others. Here we report the function and organization of the evolutionarily conserved EMC (TbEMC) in the highly diverged eukaryote, Trypanosoma brucei. Using (co-) immunoprecipitation experiments in combination with mass spectrometry and whole cell proteomic analyses of parasites after depletion of select TbEMC subunits, we demonstrate that the TbEMC is composed of 9 subunits that are present in a high molecular mass complex localizing to the mitochondrial-endoplasmic reticulum interface. Knocking out or knocking down of single TbEMC subunits led to growth defects of T. brucei procyclic forms in culture. Interestingly, we found that depletion of individual TbEMC subunits lead to disruption of de novo synthesis of phosphatidylcholine (PC) or phosphatidylethanolamine (PE), the two most abundant phospholipid classes in T. brucei. Downregulation of TbEMC1 or TbEMC3 inhibited formation of PC while depletion of TbEMC8 inhibited PE synthesis, pointing to a role of the TbEMC in phospholipid synthesis. In addition, we found that in TbEMC7 knock-out parasites, TbEMC3 is released from the complex, implying that TbEMC7 is essential for the formation or the maintenance of the TbEMC. 相似文献