全文获取类型
收费全文 | 1091篇 |
免费 | 129篇 |
国内免费 | 198篇 |
专业分类
1418篇 |
出版年
2024年 | 9篇 |
2023年 | 8篇 |
2022年 | 20篇 |
2021年 | 39篇 |
2020年 | 25篇 |
2019年 | 37篇 |
2018年 | 23篇 |
2017年 | 26篇 |
2016年 | 37篇 |
2015年 | 55篇 |
2014年 | 52篇 |
2013年 | 64篇 |
2012年 | 97篇 |
2011年 | 81篇 |
2010年 | 59篇 |
2009年 | 59篇 |
2008年 | 67篇 |
2007年 | 55篇 |
2006年 | 52篇 |
2005年 | 57篇 |
2004年 | 43篇 |
2003年 | 31篇 |
2002年 | 53篇 |
2001年 | 40篇 |
2000年 | 25篇 |
1999年 | 25篇 |
1998年 | 24篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 28篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1966年 | 3篇 |
1956年 | 4篇 |
1919年 | 2篇 |
排序方式: 共有1418条查询结果,搜索用时 31 毫秒
91.
Naeela Qureshi Harbans Bariana Kerrie Forrest Matthew Hayden Beat Keller Thomas Wicker Justin Faris Elena Salina Urmil Bansal 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2017,130(3):495-504
Key message
Fine mapping of Yr47 and Lr52 in chromosome arm 5BS of wheat identified close linkage of the marker sun180 to both genes and its robustness for marker-assisted selection was demonstrated.Abstract
The widely effective and genetically linked rust resistance genes Yr47 and Lr52 have previously been mapped in the short arm of chromosome 5B in two F3 populations (Aus28183/Aus27229 and Aus28187/Aus27229). The Aus28183/Aus27229 F3 population was advanced to generate an F6 recombinant inbred line (RIL) population to identify markers closely linked with Yr47 and Lr52. Diverse genomic resources including flow-sorted chromosome survey sequence contigs representing the orthologous region in Brachypodium distachyon, the physical map of chromosome arm 5BS, expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin and resistance gene analog contigs of chromosome arm 5BS were used to develop markers to saturate the target region. Selective genotyping was also performed using the iSelect 90 K Infinium wheat SNP assay. A set of SSR, STS, gene-based and SNP markers were developed and genotyped on the Aus28183/Aus27229 RIL population. Yr47 and Lr52 are genetically distinct genes that mapped 0.4 cM apart in the RIL population. The SSR marker sun180 co-segregated with Lr52 and mapped 0.4 cM distal to Yr47. In a high resolution mapping population of 600 F2 genotypes Yr47 and Lr52 mapped 0.2 cM apart and marker sun180 was placed 0.4 cM distal to Lr52. The amplification of a different sun180 amplicon (195 bp) than that linked with Yr47 and Lr52 (200 bp) in 204 diverse wheat genotypes demonstrated its robustness for marker-assisted selection of these genes.92.
93.
P Westermark K H Johnson G T Westermark K Sletten D W Hayden 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,85(3):609-614
Amyloid-laden renal glomeruli were selectively isolated from a cow with a history of multiple organ inflammatory diseases which terminated in amyloid-induced glomerulopathy and severe proteinuria. Lyophilized amyloid fibrils obtained by water extraction procedures were dissolved in 6M guanidine hydrochloride and gel filtered on Sepharose CL6B and Sephacryl S-300 Superfine columns for slab gel electrophoresis, analytic isoelectric focusing, and amino acid sequence analyses. Electrophoresis of material from the major retarded peak of the elution profile revealed that bovine protein AA moves as one band with an apparent molecular mass of about 14,000 Daltons. Several distinct bands between approximately pH 4.0 and 5.0 were observed when this material was evaluated by analytic isoelectric focusing, thus having a pattern resembling that of human and dog protein AA. A blocked N-terminus was demonstrated when protein from the major retarded peak was subjected to amino acid sequencing, but cyanogen bromide cleavage followed by gel filtration produced 3 peptide fragments for amino acid sequence analysis. These peptides had a high degree of homology with positions 4-14, 18-24 and 25-49 of human protein AA. An apparent complete homology between bovine protein AA and protein AA from other species was apparent at positions 35-45, providing further evidence that this is a functionally significant part of the serum protein AA (SAA) molecule. 相似文献
94.
目的:寻找靶向细胞外基质磷酸糖蛋白(MEPE)基因的微小RNA(miRNA),并检测其对人HeLa细胞内源性Mepe基因表达的影响。方法:通过NCBI检索人源Mepe的3’UTR,利用miRNA预测工具TargetScan预测可能靶向Mepe的所有miRNA,通过双萤光素酶报告基因系统检测miRNA与Mepe3’UTR的结合情况,从而初步筛选出可能靶向Mepe的miRNA;同时,用Western印迹检测miRNA经转染后对Mepe基因表达的影响。结果:利用TargetScan预测出36条可能靶向Mepe的miRNA,根据分值及匹配情况从中挑选出6条进行验证;与转染空载体pGL3-cm的相对荧光素值相比,转染miR-376a的相对荧光素值降低较为明显,而当Mepe3’UTR与miR-376a结合位点突变后,miR-376a不能抑制萤光素酶的活性;Western印迹结果显示miR-376a能明显抑制MEPE的表达。结论:miRNA-376a可能是靶向Mepe基因的miRNA,为进一步研究MEPE的功能奠定了基础。 相似文献
95.
The activating immunoreceptor NKG2D and its ligands are involved in allograft transplant rejection 总被引:2,自引:0,他引:2
Kim J Chang CK Hayden T Liu FC Benjamin J Hamerman JA Lanier LL Kang SM 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(10):6416-6420
Although the linkage between innate and adaptive immunity in transplantation has been recognized, the mechanisms underlying this cooperation remain to be fully elucidated. In this study, we show that early "danger" signals associated with transplantation lead to rapid up-regulation of NKG2D ligands. A second wave of NKG2D ligand up-regulation is mediated by the adaptive immune response to allografts. Treatment with an Ab to NKG2D was highly effective in preventing CD28-independent rejection of cardiac allografts. Notably, NKG2D blockade did not deplete CD8(+) T cells or NK1.1(+) cells nor affect their migration to the allografts. These results establish a functional role of NKG2D and its ligands in the rejection of solid organ transplants. 相似文献
96.
目的对实验动物皮肤病原真菌2种培养方法进行了比较。方法将采集到的3只皮肤真菌感染病兔样品经由沙氏平皿法和沙氏试管斜面培养法分别进行培养。结果在3只真菌感染病兔中应用试管斜面法我们只检测到1例皮肤病原真菌阳性,而采用沙氏平皿法3例阳性全部检出。结论结合临床检测经验,我们认为本研究的沙氏平皿法优于沙氏试管斜面法,在实验动物皮肤病原真菌常规检测中具有推广应用价值。 相似文献
97.
Dubsky P Hayden H Sachet M Bachleitner-Hofmann T Hassler M Pfragner R Gnant M Stift A Friedl J 《Cancer immunology, immunotherapy : CII》2008,57(6):859-870
BACKGROUND: Recent preclinical and clinical evidence suggests the use of allogeneic tumor as a source of antigen for DC-based immunotherapy against cancer. We hypothesized that addition of allogeneic tumor lysate to monocyte-derived DC culture could serve a dual purpose: (1) antigen source and (2) protein supplementation of DC culture media. Protein supplementation whether of known origin (human serum/plasma, fetal bovine serum, human serum albumin) or undeclared origin ("serum-free" media) is a source of variability and bias. We addressed the question whether protein supplementation can be omitted in the presence of allogeneic tumor lysate. MATERIALS AND METHODS: Human DC cultured in the presence of lysate from medullary thyroid carcinoma (MTC) cell line SHER-I (TuLy-DC) and DC pulsed with the same lysate but cultured in the presence of FBS (FBS-DC) were assessed for morphology, phenotype, maturation and functional properties. RESULTS: In comparison of FBS-DC/TuLy-DC no significant differences in morphology, phenotype and maturation could be detected. Both culture conditions produced CD1a(high), CD14(low) DC with high expression of costimulatory molecules and CD83 upon stimulation. TuLy-DC gave significantly better yields and produced more IL12p70. DC showed high (allo)stimulatory capacity toward T-cells. TuLy-DC induced more intracellular IFNgamma in CD8+T-cells of vaccinated MTC patients. Both types of DC induced killing of SHER-I after short in vitro restimulation. Tumor lysate from SHER-I can substitute for further protein supplementation in DC culture. Allogeneic tumor lysates should be taken into consideration as both source of antigen and protein supplementation in monocyte-derived DC culture. 相似文献
98.
T. WORTHINGTON P. S. KEMP P. E. OSBORNE A. DILLEN J. COECK M. BUNZEL‐DRÜKE M. NAURA J. GREGORY K. EASTON 《Freshwater Biology》2012,57(3):602-611
1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas. 相似文献
99.
100.
John O’Brien Gary F. McCracken Ludovic Say Thomas J. Hayden 《Conservation Genetics》2007,8(5):1073-1082
Fruit bats of the genus Pteropus are important contributors to ecosystem maintenance on islands through their roles as pollinators and seed dispersers. However,
island faunas are the most prone to extinction and there is a real need to assess the possible genetic implications of population
reductions in terms of extinction risk. An effective method of ameliorating extinction risk in endangered species is the establishment
of captive populations ex situ. The effectiveness of captive breeding programmes may be assessed by comparing the genetic
variability of captive colonies to that of wild counterparts. Here, we use polymorphic microsatellite loci to assess genetic
variability in wild, critically endangered Rodrigues fruit bats (Pteropus rodricensis, Dobson 1878) and we compare this variability to that in a captive colony. We document remarkable conservation of genetic
variability in both the wild and captive populations, despite population declines and founder events. Our results demonstrate
that the wild population has withstood the negative effects of population reductions and that captive breeding programmes
can fulfil the goals of retaining genetic diversity and limiting inbreeding. 相似文献