全文获取类型
收费全文 | 1910篇 |
免费 | 118篇 |
国内免费 | 180篇 |
专业分类
林业 | 65篇 |
农学 | 715篇 |
172篇 | |
综合类 | 465篇 |
农作物 | 191篇 |
水产渔业 | 102篇 |
畜牧兽医 | 267篇 |
园艺 | 124篇 |
植物保护 | 107篇 |
出版年
2024年 | 4篇 |
2023年 | 19篇 |
2022年 | 38篇 |
2021年 | 61篇 |
2020年 | 62篇 |
2019年 | 70篇 |
2018年 | 48篇 |
2017年 | 62篇 |
2016年 | 73篇 |
2015年 | 87篇 |
2014年 | 101篇 |
2013年 | 99篇 |
2012年 | 92篇 |
2011年 | 114篇 |
2010年 | 115篇 |
2009年 | 136篇 |
2008年 | 117篇 |
2007年 | 117篇 |
2006年 | 127篇 |
2005年 | 111篇 |
2004年 | 96篇 |
2003年 | 84篇 |
2002年 | 60篇 |
2001年 | 66篇 |
2000年 | 49篇 |
1999年 | 42篇 |
1998年 | 32篇 |
1997年 | 19篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2208条查询结果,搜索用时 15 毫秒
81.
Generalized marker regression and interval QTL mapping methods for binary traits in half-sib family designs 总被引:3,自引:0,他引:3
H. N. Kadarmideen & J. C. M. Dekkers 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2001,118(5):297-309
A Generalized Marker Regression Mapping (GMR) approach was developed for mapping Quantitative Trait Loci (QTL) affecting binary polygenic traits in a single-family half-sib design. The GMR is based on threshold-liability model theory and regression of offspring phenotype on expected marker genotypes at flanking marker loci. Using simulation, statistical power and bias of QTL mapping for binary traits by GMR was compared with full QTL interval mapping based on a threshold model (GIM) and with a linear marker regression mapping method (LMR). Empirical significance threshold values, power and estimates of QTL location and effect were identical for GIM and GMR when QTL mapping was restricted to within the marker interval. These results show that the theory of the marker regression method for QTL mapping is also applicable to binary traits and possibly for traits with other non-normal distributions. The linear and threshold models based on marker regression (LMR and GMR) also resulted in similar estimates and power for large progeny group sizes, indicating that LMR can be used for binary data for balanced designs with large families, as this method is computationally simpler than GMR. GMR may have a greater potential than LMR for QTL mapping for binary traits in complex situations such as QTL mapping with complex pedigrees, random models and models with interactions. 相似文献
82.
83.
84.
85.
Jerzy Drzewiecki 《Euphytica》2001,119(3):279-287
Wheat-rye translocation line (2BS/2RL) has been developed for resistance to biotype L of Hessian fly and agronomically useful
traits. AFLP analysis using 64 primer pairs was conducted in order to identify 2RL-specific polymorphisms between “Coker 797”
(non-2RL), near-isogenic line (NIL) carrying 2RL, and “Hamlet”. Nine primer combinations identified twelve reproducible polymorphic
fragments in the NIL carrying 2RL. These twelve fragments were cloned and sequenced with an aim towards converting AFLP markers
into sequence tagged sites (STS). A comparison of the 12 sequences with non-redundant accessions in the NCBI database using
the BLAST search option indicated that one fragment of approximately 200 bp in length (amplified using primer combination
E+AAC / M+CTA) was highly homologous with the rye-specific repetitive sequence R173-1 and Wis-2-lA, a retrotransposon-like
element in wheat. Two STS primers (SJ07 and SJ09) out of twelve STS primer sets enabled the detection of polymorphisms between
Coker 797 and NIL carrying 2RL. In order to verify whether the polymorphism detected by primers SJ07 and SJ09 was in fact
the result of the presence of 2RL, additional plant material was examined. Amplified products of about 260 bp fragment with
the SJ07 primer set were generated in rye cvs.“Chilbohomil” and “Jochunhomil”, triticale experimental line Suwon 15, and wheat
experimental line K-14 (1AL/1RS & 2BS/2RL), as well as NIL carrying 2RL and Hamlet, but not in Coker 797 (non-2RL), “Keumgangmil”
(non-translocation wheat), KS92WGRC17 (PI592729 /;/ 6BS/6BL-6RL), KS92WGRC19 (P1592731 /;/ 4BS/4BL-6RL), “TAM200” (1AL/1RS),
and “Siouxland” (1BL/1RS). Our data suggest that primer set SJ07 amplifies a “2RL-specific” fragment of diagnostic value.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
86.
Intraspecific olive diversity assessed with AFLP 总被引:6,自引:0,他引:6
F. Sanz-Cortés D. E. Parfitt C. Romero D. Struss G. Llacer M. L. Badenes 《Plant Breeding》2003,122(2):173-177
Amplified fragment length polymorphism (AFLP) was used to study diversity within and among Spanish olive varieties. A high degree of diversity was found among the varieties present in each growing region. Olive oil production and quality relies on appropriate cultivar selection as well as good orchard management. Production based only on a few superior cultivars would result in improved yield, oil quality, and production management. Amplified fragment length polymorphism were evaluated as a tool to identify the intraspecific and intravarietal diversity of olive. Amplified fragment length polymorphism analysis of 38 accessions belonging to 10 cultivars using six primer combinations produced 106 polymorphic bands. Results were analyzed for similarity among accessions via unweighted pair‐group means cluster analysis, resulting in 10 clusters corresponding to named variety designations. Similarity among varieties ranged from 0.60 to 0.72. Diversity within varieties was identified. Similarity within named varieties (accessions with the same varietal name) ranged from 0.75 to 0.96. Differences in several markers were found among 34 accessions. Intravarietal diversity was shown to exist within the Spanish olive varieties grown in the region surrounding Valencia. 相似文献
87.
The 541 × Ot1-3 intercross population and bulked segregant analysis (BSA) were used to search for molecular markers linked to genes underlying sprouting and alpha-amylase activity. Six RAPD markers showing association with studied traits were tested for their potential effectiveness in selecting sprouting resistant genotypes. It was shown that although individual effects of markers were not high, their accumulation in one genotype gives substantial increase in sprouting resistance. 相似文献
88.
Polymorphism and ontogeny of 11 chicory (Cichorium intybus L.) enzymatic systems have been analyzed by native polyacrylamide gel electrophoresis, namely: leucine aminopeptidase, phosphoglucomutase, shikimate dehydrogenase, glutamate oxaloacetate transaminase, superoxide dismutase, isocitrate dehydrogenase, esterase, phosphorylase, glucose-6-phosphate dehydrogenase, 6-phos-phogluconate dehydrogenase and glucose phosphate isomerase. The use of these systems as biochemical markers is discussed. 相似文献
89.
An introduction to markers, quantitative trait loci (QTL) mapping and marker-assisted selection for crop improvement: The basic concepts 总被引:24,自引:2,他引:24
Recognizing the enormous potential of DNA markers in plant breeding, many agricultural research centers and plant breeding institutes have adopted the capacity for marker development and marker-assisted selection (MAS). However, due to rapid developments in marker technology, statistical methodology for identifying quantitative trait loci (QTLs) and the jargon used by molecular biologists, the utility of DNA markers in plant breeding may not be clearly understood by non-molecular biologists. This review provides an introduction to DNA markers and the concept of polymorphism, linkage analysis and map construction, the principles of QTL analysis and how markers may be applied in breeding programs using MAS. This review has been specifically written for readers who have only a basic knowledge of molecular biology and/or plant genetics. Its format is therefore ideal for conventional plant breeders, physiologists, pathologists, other plant scientists and students. 相似文献
90.
Summary Random amplified polymorphic DNA (RAPD) analysis was carried out to evaluate polymorphism and genetic similarity between 39 Mediterranean mandarin genotypes. One hundred eleven amplification products were identified using 21 random primers. An average of 2.2 RAPD markers was obtained for each primer, corresponding to 42% of the amplification products. Genotype-specific RAPD markers were also found, mainly in known hybrids. UPGMA cluster analysis revealed the low level of genetic variation between accessions of Mediterranean mandarins, whereas their hybrids with other Citrus species showed greater genetic dissimilarity. Twenty accessions yielded very similar patterns, suggesting either that they could be a single clone, or that the technique was not able to detect genomic variation. However, for the other specimens genetic polymorphism can easily be detected by RAPD, although the genetic variation between accessions was quite low. The large number of hybrids and the low polymorphism between accessions support the hypothesis that Mediterranean mandarins are all true hybrid of Common mandarins (Citrus reticulata Blanco). 相似文献