全文获取类型
| 收费全文 | 3942篇 |
| 免费 | 969篇 |
| 国内免费 | 288篇 |
专业分类
| 林业 | 154篇 |
| 农学 | 1100篇 |
| 基础科学 | 6篇 |
| 214篇 | |
| 综合类 | 1800篇 |
| 农作物 | 657篇 |
| 水产渔业 | 260篇 |
| 畜牧兽医 | 504篇 |
| 园艺 | 350篇 |
| 植物保护 | 154篇 |
出版年
| 2025年 | 71篇 |
| 2024年 | 80篇 |
| 2023年 | 86篇 |
| 2022年 | 107篇 |
| 2021年 | 137篇 |
| 2020年 | 117篇 |
| 2019年 | 117篇 |
| 2018年 | 127篇 |
| 2017年 | 139篇 |
| 2016年 | 198篇 |
| 2015年 | 186篇 |
| 2014年 | 222篇 |
| 2013年 | 205篇 |
| 2012年 | 319篇 |
| 2011年 | 361篇 |
| 2010年 | 297篇 |
| 2009年 | 344篇 |
| 2008年 | 319篇 |
| 2007年 | 376篇 |
| 2006年 | 297篇 |
| 2005年 | 259篇 |
| 2004年 | 190篇 |
| 2003年 | 147篇 |
| 2002年 | 92篇 |
| 2001年 | 90篇 |
| 2000年 | 87篇 |
| 1999年 | 64篇 |
| 1998年 | 40篇 |
| 1997年 | 25篇 |
| 1996年 | 20篇 |
| 1995年 | 14篇 |
| 1994年 | 11篇 |
| 1993年 | 8篇 |
| 1992年 | 13篇 |
| 1991年 | 5篇 |
| 1990年 | 4篇 |
| 1989年 | 5篇 |
| 1988年 | 2篇 |
| 1987年 | 2篇 |
| 1986年 | 2篇 |
| 1985年 | 1篇 |
| 1981年 | 2篇 |
| 1980年 | 2篇 |
| 1979年 | 1篇 |
| 1978年 | 2篇 |
| 1963年 | 4篇 |
| 1962年 | 1篇 |
| 1956年 | 1篇 |
排序方式： 共有5199条查询结果，搜索用时 9 毫秒
1.
Rachayya M. Devarumath Sachin B. Kalwade Peter Bundock Frances G. Eliott Robert Henry 《Plant Breeding》2013,132(6):736-747
The independent target region amplification polymorphism (TRAP) and single‐nucleotide polymorphism (SNP) marker s were used for genetic evaluation of different selected 47 sugarcane genotypes. A total of 23 pairs of TRAP markers generated 925 alleles, of which 74% alleles were polymorphic. Polymorphism was generally high (>50%), ranging from 54 to 98%. The polymorphism information content (PIC) values 0.20 varied among the primer combination ranging from 0.17 in SAI + Arbi 2 to 0.31 in GL 2+ Arbi 1 with an average of 0.24. However, the Pearson correlation between PIC and power of discrimination (PD) was found to be less significant. Single‐nucleotide polymorphisms were used first time for the assessment of genetic diversity among different species of Saccharum and cultivated sugarcane varieties. The SNPs were detected from 454 sequencing. A total of 245 SNP markers were assayed across the 47 genotypes, and 167 SNPs were found to be polymorphic. The PIC values ranged from 0.04 to 0.38 with an average of 0.21, and their respective PD varied from 0.58 to 0.04 with an average value of 0.31. The obtained results relatively significant were compared with the other marker systems through genetic similarity and the clusters formed in different unweighted pair group method with arithmetic mean clustering dendrogram. The clustering analysis established genetic relationship in the order of Erianthus > Sclerostachya > Narenga > Saccharum spontaneum > S. robustum > S. barberi > S. officinarum/cultivars. These results ratify TRAP and SNP marker systems for assessing genetic diversity studies, and more diversified Erianthus spp. can contribute substantially towards sugarcane varietal improvement through breeding with Saccharum spp. or hybrid cultivars. 相似文献
2.
利用系谱分析和SSR标记对河南省小麦主要推广品种间的亲缘关系进行了研究。结果如下:(1)系谱分析表明10个主要推广品种间的血缘关系较近,豫麦2号和丰产3号是它们的骨干亲本,分别与7个和9个品种有血缘关系;(2)70对SSR引物在11个品种间扩增出211个等位变异,平均每个引物3.01个,84.29%的引物能检测到多态性位点,Xgwm294和barc061就能将这11个品种区分开;(3)品种间的遗传距离平均为0.495,变化范围较小,在0.36到0.63之间;(4)不同共同血缘比例的品种间的遗传距离差异较小,表明品种间的亲缘关系较近;(5)有1/2和1/4共同血缘的品种间的遗传距离较近,低于1/4共同血缘和无血缘品种间的遗传距离稍远,血缘关系不能很好反映品种间的亲缘远近。 相似文献
3.
本研究采用作试验改进的脲－酚－氯仿－醇－ＳＤＳ系统方法,对江西畜牧良种场奶牛一分场的黑白花奶牛群的５头公牛家系的１９１对母女牛进行了血液ＲＮＡ的测定,分析了被测奶牛血液ＲＮＡ含量的变化的规律性及其与产奶量的关系,建立了利用血液ＲＮＡ含量估测产奶量的回归方程。测定分析结果：试验牛血液ＲＮＡ遗传力（ｈ＾２）及其与产奶量的遗传相关（ｒＡ）分别为０．８５５８（Ｐ〈０．０５）与０．５８１７（Ｐ〈０．０５） 相似文献
4.
Arnold S. Parco Mavir C. Avellaneda Anna H. Hale Jeffrey W. Hoy Collins A. Kimbeng Michael J. Pontif Kenneth A. Gravois Niranjan Baisakh 《Plant Breeding》2014,133(5):654-659
Brown rust, caused by the fungus Puccinia melanocephala, poses an increasing threat to sugarcane industries worldwide. Recently, markers R12H16 and 9020‐F4 were developed for a major resistance gene Bru1 that contributes to a significant proportion of brown rust resistance in multiple sugarcane industries. Marker‐assisted screening of Louisiana sugarcane germplasm showed a low frequency (4.3%, five out of 117 clones) of Bru1 among sugarcane cultivars and elite breeding clones. Likewise, among progeny of crosses involving wild/exotic germplasm, only 14 of 208 clones (6.7%) tested Bru1 positive. However, Bru1 frequency was higher (28.7%, 52 of 181 clones) in wild/exotic germplasm, which indicated that diverse genetic resources are available for Bru1 introgression. Commercial Bru1‐positive cultivar, ‘L 01‐299', was resistant to brown rust. However, Bru1‐positive cultivar, ‘L 10‐146’, was susceptible while Bru1‐negative cultivars, such as ‘L 99‐233’, showed resistance to brown rust. Bru1‐negative clones with brown rust resistance offer an opportunity to identify alternate sources of resistance, which can be pyramided with Bru1 for effective and durable resistance in sugarcane against the changing pathogen. 相似文献
5.
6.
Several SNP (single nucleotide polymorphism) genotyping methods have been developed in the past most of which require sophisticated instrumentation and large initial investments. We describe here a high-throughput SSCP (single strand conformation polymorphism) system on our HEGS (high efficiency genome scanning) platform, which is simple, accurate, cost effective and requires neither restriction digestion of the amplification products nor elaborate post-PCR processing detection. Several parameters critical to SSCP analysis were optimized viz., gel matrix and concentration, gel running temperature, buffer composition, running conditions and PCR primer design so as to identify SNPs in amplicons ranging from 100 to 750 bp in size. A simple post-PCR processing system was developed using fluorescent dye for quick and easy detection of SNP polymorphism. HEGS-SSCP was also found to be useful in uncovering simple sequence repeat differences between different genotypes that differ by one or few di/tri nucleotide repeats. The practical utility of this system is illustrated with two successful efforts towards construction of high resolution linkage maps of a lesion mimic locus on chromosome 7 and a major quantitative trait locus conditioning field blast resistance on chromosome 4 in rice. 相似文献
7.
8.
K. Humbroich H. Jaiser A. Schiemann P. Devaux A. Jacobi L. Cselenyi A. Habekuss W. Friedt F. Ordon 《Plant Breeding》2010,129(3):346-348
9.
本文综述了橡胶树遗传育种中的分子标记应用研究进展,并展望了其在我国橡胶树遗 传育种研究中的应用前景。 相似文献
10.
Genetic diversity, as revealed by eighteenSimple Sequence Repeat (SSR) markers inthirty almond [P. dulcis (Mill.) D.A.Webb], twenty fresh-market peach [Prunus persica (L.), Basch], fifteenprocessing clingstone peach cultivars, andten rootstocks, established the geneticrelatedness among cultivars andcharacterized the variation within andbetween species. One accession each of thewild Prunus species, P.davidiana [(Carriere) Franch] and P.webbii [(Spach.) Vieh.], was included inthe analysis. The number of presumedalleles revealed by the SSR analysis rangedfrom one to six in peach whereas almondcultivars showed a range of three to nine.Peach cultivars clustered into ten groups,which are in general agreement withdocumented origin. Most processingclingstone peach cultivars clusteredseparately from fresh-market freestonecultivars supporting a distinct origin. Twomajor clusters were observed in almond withone containing California cultivars and theother containing European cultivars and theimportant California cultivar Mission.Results establish the value of SSR markersfor distinguishing different geneticlineages and characterize an extensive andlargely unexploited inter-species gene poolavailable to peach and almond breedingprograms. 相似文献