全文获取类型
收费全文 | 507篇 |
免费 | 53篇 |
国内免费 | 2篇 |
出版年
2021年 | 10篇 |
2020年 | 13篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 17篇 |
2012年 | 26篇 |
2011年 | 25篇 |
2010年 | 16篇 |
2009年 | 15篇 |
2008年 | 15篇 |
2007年 | 20篇 |
2006年 | 14篇 |
2005年 | 22篇 |
2004年 | 21篇 |
2003年 | 26篇 |
2002年 | 16篇 |
2001年 | 23篇 |
2000年 | 15篇 |
1999年 | 18篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 18篇 |
1989年 | 16篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 10篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1968年 | 2篇 |
排序方式: 共有562条查询结果,搜索用时 15 毫秒
91.
Lau J Alberts AC Chemnick LG Gerber GP Jones KC Mitchell AA Ryder OA 《Molecular ecology resources》2009,9(5):1412-1414
Twenty-three polymorphic microsatellite markers were identified and characterized for Cyclura pinguis, a critically endangered species of lizard (Sauria: Iguanidae) native to Anegada Island in the British Virgin Islands. We examined variation at these loci for 39 C. pinguis, finding up to five alleles per locus and an average expected heterozygosity of 0.55. Allele frequency estimates for these microsatellite loci will be used to characterize genetic diversity of captive and wild C. pinguis populations and to estimate relatedness among adult iguanas at the San Diego Zoo that form the nucleus of a captive breeding programme for this critically endangered species. 相似文献
92.
Pedro LC Pinheiro João CR Cardoso Ana S Gomes Juan Fuentes Deborah M Power Adelino VM Canário 《BMC evolutionary biology》2010,10(1):373
Background
Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evolution of these proteins. Although PTH and PTHrP have been intensively studied in mammals their function in other vertebrates is poorly documented. Amphibians and birds occupy unique phylogenetic positions, the former at the transition of aquatic to terrestrial life and the latter at the transition to homeothermy. Moreover, both organisms have characteristics indicative of a complex system in calcium regulation. This study investigated PTH family evolution in vertebrates with special emphasis on Xenopus and chicken. 相似文献93.
UNC-6/netrin and SLT-1/slit guidance cues orient axon outgrowth mediated by MIG-10/RIAM/lamellipodin
Quinn CC Pfeil DS Chen E Stovall EL Harden MV Gavin MK Forrester WC Ryder EF Soto MC Wadsworth WG 《Current biology : CB》2006,16(9):845-853
BACKGROUND: Axon migrations are guided by extracellular cues that can act as repellants or attractants. However, the logic underlying the manner through which attractive and repulsive responses are determined is unclear. Many extracellular guidance cues, and the cellular components that mediate their signals, have been implicated in both types of responses. RESULTS: Genetic analyses indicate that MIG-10/RIAM/lamellipodin, a cytoplasmic adaptor protein, functions downstream of the attractive guidance cue UNC-6/netrin and the repulsive guidance cue SLT-1/slit to direct the ventral migration of the AVM and PVM axons in C. elegans. Furthermore, overexpression of MIG-10 in the absence of UNC-6 and SLT-1 induces a multipolar phenotype with undirected outgrowths. Addition of either UNC-6 or SLT-1 causes the neurons to become monopolar. Moreover, the ability of UNC-6 or SLT-1 to direct the axon ventrally is enhanced by the MIG-10 overexpression. We also demonstrate that an interaction between MIG-10 and UNC-34, a protein that promotes actin-filament extension, is important in the response to guidance cues and that MIG-10 colocalizes with actin in cultured cells, where it can induce the formation of lamellipodia. CONCLUSIONS: We conclude that MIG-10 mediates the guidance of AVM and PVM axons in response to the extracellular UNC-6 and SLT-1 guidance cues. The attractive and repulsive guidance cues orient MIG-10-dependant axon outgrowth to cause a directional response. 相似文献
94.
Woods A Heslegrave AJ Muckett PJ Levene AP Clements M Mobberley M Ryder TA Abu-Hayyeh S Williamson C Goldin RD Ashworth A Withers DJ Carling D 《The Biochemical journal》2011,434(1):49-60
LKB1 is a 'master' protein kinase implicated in the regulation of metabolism, cell proliferation, cell polarity and tumorigenesis. However, the long-term role of LKB1 in hepatic function is unknown. In the present study, it is shown that hepatic LKB1 plays a key role in liver cellular architecture and metabolism. We report that liver-specific deletion of LKB1 in mice leads to defective canaliculi and bile duct formation, causing impaired bile acid clearance and subsequent accumulation of bile acids in serum and liver. Concomitant with this, it was found that the majority of BSEP (bile salt export pump) was retained in intracellular pools rather than localized to the canalicular membrane in hepatocytes from LLKB1KO (liver-specific Lkb1-knockout) mice. Together, these changes resulted in toxic accumulation of bile salts, reduced liver function and failure to thrive. Additionally, circulating LDL (low-density lipoprotein)-cholesterol and non-esterified cholesterol levels were increased in LLKB1KO mice with an associated alteration in red blood cell morphology and development of hyperbilirubinaemia. These results indicate that LKB1 plays a critical role in bile acid homoeostasis and that lack of LKB1 in the liver results in cholestasis. These findings indicate a novel key role for LKB1 in the development of hepatic morphology and membrane targeting of canalicular proteins. 相似文献
95.
Billam P Bonaparte KL Liu J Ruckwardt TJ Chen M Ryder AB Wang R Dash P Thomas PG Graham BS 《The Journal of biological chemistry》2011,286(6):4829-4841
CD8+ T cell responses are important for recognizing and resolving viral infections. To better understand the selection and hierarchy of virus-specific T cell responses, we compared the T cell receptor (TCR) clonotype in parent and hybrid strains of respiratory syncytial virus-infected mice. K(d)M2(82-90) (SYIGSINNI) in BALB/c and D(b)M(187-195) (NAITNAKII) in C57Bl/6 are both dominant epitopes in parent strains but assume a distinct hierarchy, with K(d)M2(82-90) dominant to D(b)M(187-195) in hybrid CB6F1/J mice. The dominant K(d)M2(82-90) response is relatively public and is restricted primarily to the highly prevalent Vβ13.2 in BALB/c and hybrid mice, whereas D(b)M(187-195) responses in C57BL/6 mice are relatively private and involve multiple Vβ subtypes, some of which are lost in hybrids. A significant frequency of TCR CDR3 sequences in the D(b)M(187-195) response have a distinct "(D/E)WG" motif formed by a limited number of recombination strategies. Modeling of the dominant epitope suggested a flat, featureless structure, but D(b)M(187-195) showed a distinctive structure formed by Lys(7). The data suggest that common recombination events in prevalent Vβ genes may provide a numerical advantage in the T cell response and that distinct epitope structures may impose more limited options for successful TCR selection. Defining how epitope structure is interpreted to inform T cell function will improve the design of future gene-based vaccines. 相似文献
96.
B. Sosinski M. Gannavarapu L. D. Hager L. E. Beck G.J. King C. D. Ryder S. Rajapakse W. V. Baird R. E. Ballard A. G. Abbott 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(3):421-428
Microsatellites have emerged as an important system of molecular markers. We evaluated the potential of microsatellites for
use in genetic studies of peach [Prunus persica (L.) Batsch]. Microsatellite loci in peach were identified by screening a pUC8 genomic library, a λZAPII leaf cDNA library,
as well as through database searches. Primer sequences for the microsatellite loci were tested from the related Rosaceae species
apple (Malus×domestica) and sour cherry (Prunus cerasus L.). The genomic library was screened for CT, CA and AGG repeats, while the cDNA library was screened for (CT)n- and (CA)n-containing clones. Estimates of microsatellite frequencies were determined from the genomic library screening, and indicate
that CT repeats occur every 100 kb, CA repeats every 420 kb, and AGG repeats every 700 kb in the peach genome. Microsatellite-
containing clones were sequenced, and specific PCR primers were designed to amplify the microsatellite- containing regions
from genomic DNA. The level of microsatellite polymorphism was evaluated among 28 scion peach cultivars which displayed one
to four alleles per primer pair. Five microsatellites were found to segregate in intraspecific peach-mapping crosses. In addition,
these microsatellite markers were tested for their utility in cross-species amplification for use in comparative mapping both
within the Rosaceae, and with the un- related species Arabidopsis thaliana L.
Received: 18 June 1999 / Accepted: 6 December 1999 相似文献
97.
T R Ryder L Y Hu M F Rafferty S M Lotarski D M Rock S J Stoehr C P Taylor M L Weber G P Miljanich E Millerman B G Szoke 《Bioorganic & medicinal chemistry letters》1999,9(16):2453-2458
Selective N-Type Voltage Sensitive Calcium Channel (VSCC) antagonists have shown utility in several models of pain and ischemia. We report the structure-activity relationship at the proximal phenyl group in a series of non-peptidyl VSCC blockers. 相似文献
98.
BIOLOG系统鉴定黄瓜根围促生菌的初步研究 总被引:8,自引:0,他引:8
对筛选出的8株具有明显促生防病作用的黄瓜根围促生菌CN11,CN31,CN45,CN1 16,CN129,XB120,XB5,XB41通过BIOLOG法进行了分类鉴定,分别为:铜绿假单胞菌(Psendomonas aeruginosa),波纹假单胞菌(P. Corrugata),短芽孢杆菌(Bacillus brevis),荧光假单胞菌B型(P. Fluorescens type B),铜绿假单胞菌(P. Aeruginosa),荧光假 相似文献
99.
Copper has been demonstrated in the feet of slugs exposed to the molluscicide copper sulfate. Using the scanning electron microscope coupled with X-ray microanalysis, copper was localized to the epithelium of the foot. Under the transmission electron microscope the subcellular distribution of copper was obtained by precipitating the molluscicide with potassium ferrocyanide. The reaction product was both electron opaque and insoluble in the preparative media. The precipitate was localized in the zonula adhaerens and septate junctions between adjacent epithelial cells. Reaction product was also present in some of the pinocytotic vesicles of the epithelial cells. The identity of the reaction product was confirmed using X-ray microanalysis. 相似文献
100.