全文获取类型
收费全文 | 316篇 |
免费 | 31篇 |
专业分类
347篇 |
出版年
2022年 | 3篇 |
2021年 | 7篇 |
2017年 | 9篇 |
2016年 | 4篇 |
2015年 | 10篇 |
2014年 | 6篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 18篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 13篇 |
2005年 | 15篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 17篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1974年 | 4篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1954年 | 1篇 |
1953年 | 1篇 |
1947年 | 1篇 |
1946年 | 1篇 |
1940年 | 1篇 |
1928年 | 1篇 |
1927年 | 2篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
31.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
32.
33.
Jewell WH 《Proceedings of the Royal Society of Medicine》1927,20(10):1630-1631
34.
35.
Summary Touch preparations of human placenta yield cells retaining antigenic reactivity to immunoperoxidase stains for and chains of human chorionic gonadotropin, placental lactogen, and pregnancy-specific glycoprotein. This method is a rapid and simple alternative to conventional frozen and paraffin-embedded sections for detection of placental peptides. 相似文献
36.
Minobe E Hao LY Saud ZA Xu JJ Kameyama A Maki M Jewell KK Parr T Bardsley RG Kameyama M 《Biochemical and biophysical research communications》2006,348(1):288-294
Calpastatin, an endogenous inhibitor of calpain, is composed of domain L and four repetitive homologous domains 1-4. Domains 1-4 inhibit calpain, whereas domain L partially reprimes L-type Ca2+ channels for voltage-gated activation. In the present study, the effects on Ca2+ channel activity of four isoforms and a series of fragments of calpastatin domain L were investigated in guinea-pig ventricular myocytes with the patch-clamp method. With one exception, all the isoforms and fragment peptides that contained amino acid residues 54-64 of domain L reprimed the Ca2+ channels to comparable levels (9-15% of control activity) to those observed previously with a full-length form of calpastatin. These results suggest that the region containing amino acid residues 54-64 (EGKPKEHTEPK) is responsible for the Ca2+ channel repriming function of calpastatin domain L. 相似文献
37.
Sarah McDavid Mary Beth Bauer Rebecca L. Brindley Mark L. Jewell Kevin P. M. Currie 《PloS one》2014,9(10)
Butanol (C4H10OH) has been used both to dissect the molecular targets of alcohols/general anesthetics and to implicate phospholipase D (PLD) signaling in a variety of cellular functions including neurotransmitter and hormone exocytosis. Like other primary alcohols, 1-butanol is a substrate for PLD and thereby disrupts formation of the intracellular signaling lipid phosphatidic acid. Because secondary and tertiary butanols do not undergo this transphosphatidylation, they have been used as controls for 1-butanol to implicate PLD signaling. Recently, selective pharmacological inhibitors of PLD have been developed and, in some cases, fail to block cellular functions previously ascribed to PLD using primary alcohols. For example, exocytosis of insulin and degranulation of mast cells are blocked by primary alcohols, but not by the PLD inhibitor FIPI. In this study we show that 1-butanol reduces catecholamine secretion from adrenal chromaffin cells to a much greater extent than tert-butanol, and that the PLD inhibitor VU0155056 has no effect. Using fluorescent imaging we show the effect of these drugs on depolarization-evoked calcium entry parallel those on secretion. Patch-clamp electrophysiology confirmed the peak amplitude of voltage-gated calcium channel currents (ICa) is inhibited by 1-butanol, with little or no block by secondary or tert-butanol. Detailed comparison shows for the first time that the different butanol isomers exert distinct, and sometimes opposing, effects on the voltage-dependence and gating kinetics of ICa. We discuss these data with regard to PLD signaling in cellular physiology and the molecular targets of general anesthetics. 相似文献
38.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献
39.
Jewell Dennis E. Tavener Selena K. Hollar Regina L. Panickar Kiran S. 《Metabolomics : Official journal of the Metabolomic Society》2022,18(8):1-5
Metabolomics - The global population is aging. Preserving function and independence of our aging population is paramount. A key component to maintaining independence is the preservation of... 相似文献
40.
Jewell JL Oh E Ramalingam L Kalwat MA Tagliabracci VS Tackett L Elmendorf JS Thurmond DC 《The Journal of cell biology》2011,193(1):185-199
How the Sec1/Munc18-syntaxin complex might transition to form the SNARE core complex remains unclear. Toward this, Munc18c tyrosine phosphorylation has been correlated with its dissociation from syntaxin 4. Using 3T3-L1 adipocytes subjected to small interfering ribonucleic acid reduction of Munc18c as a model of impaired insulin-stimulated GLUT4 vesicle exocytosis, we found that coordinate expression of Munc18c-wild type or select phosphomimetic Munc18c mutants, but not phosphodefective mutants, restored GLUT4 vesicle exocytosis, suggesting a requirement for Munc18c tyrosine phosphorylation at Tyr219 and Tyr521. Surprisingly, the insulin receptor (IR) tyrosine kinase was found to target Munc18c at Tyr521 in vitro, rapidly binding and phosphorylating endogenous Munc18c within adipocytes and skeletal muscle. IR, but not phosphatidylinositol 3-kinase, activation was required. Altogether, we identify IR as the first known tyrosine kinase for Munc18c as part of a new insulin-signaling step in GLUT4 vesicle exocytosis, exemplifying a new model for the coordination of SNARE assembly and vesicle mobilization events in response to a single extracellular stimulus. 相似文献