全文获取类型
收费全文 | 24768篇 |
免费 | 1581篇 |
国内免费 | 2400篇 |
专业分类
林业 | 1617篇 |
农学 | 1586篇 |
基础科学 | 1167篇 |
2792篇 | |
综合类 | 11868篇 |
农作物 | 1674篇 |
水产渔业 | 741篇 |
畜牧兽医 | 4222篇 |
园艺 | 1850篇 |
植物保护 | 1232篇 |
出版年
2024年 | 178篇 |
2023年 | 523篇 |
2022年 | 1204篇 |
2021年 | 1223篇 |
2020年 | 1140篇 |
2019年 | 1098篇 |
2018年 | 754篇 |
2017年 | 1226篇 |
2016年 | 827篇 |
2015年 | 1281篇 |
2014年 | 1274篇 |
2013年 | 1532篇 |
2012年 | 2257篇 |
2011年 | 2201篇 |
2010年 | 2063篇 |
2009年 | 1886篇 |
2008年 | 1773篇 |
2007年 | 1559篇 |
2006年 | 1230篇 |
2005年 | 1001篇 |
2004年 | 604篇 |
2003年 | 373篇 |
2002年 | 363篇 |
2001年 | 353篇 |
2000年 | 336篇 |
1999年 | 150篇 |
1998年 | 43篇 |
1997年 | 45篇 |
1996年 | 37篇 |
1995年 | 35篇 |
1994年 | 24篇 |
1993年 | 28篇 |
1992年 | 25篇 |
1991年 | 12篇 |
1990年 | 20篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 3篇 |
1966年 | 1篇 |
1962年 | 4篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1956年 | 14篇 |
1955年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
131.
Lihua Ning Guizhen Kan Wenkai Du Shiwei Guo Qing Wang Guozheng Zhang Hao Cheng Deyue Yu 《Breeding Science》2016,66(2):191-203
Tolerance to low-phosphorus soil is a desirable trait in soybean cultivars. Previous quantitative trait locus (QTL) studies for phosphorus-deficiency tolerance were mainly derived from bi-parental segregating populations and few reports from natural population. The objective of this study was to detect QTLs that regulate phosphorus-deficiency tolerance in soybean using association mapping approach. Phosphorus-deficiency tolerance was evaluated according to five traits (plant shoot height, shoot dry weight, phosphorus concentration, phosphorus acquisition efficiency and use efficiency) comprising a conditional phenotype at the seedling stage. Association mapping of the conditional phenotype detected 19 SNPs including 13 SNPs that were significantly associated with the five traits across two years. A novel cluster of SNPs, including three SNPs that consistently showed significant effects over two years, that associated with more than one trait was detected on chromosome 3. All favorable alleles, which were determined based on the mean of conditional phenotypic values of each trait over the two years, could be pyramided into one cultivar through parental cross combination. The best three cross combinations were predicted with the aim of simultaneously improving phosphorus acquisition efficiency and use efficiency. These results will provide a thorough understanding of the genetic basis of phosphorus deficiency tolerance in soybean. 相似文献
132.
选用与Yr18基因和1BL/1RS易位系紧密连锁的SCAR和STS标记,对天水106份供试冬小麦育成品种(系)Yr18基因、1BL/1RS易位系的分布情况进行分子检测。结果表明,106份材料中,有2份材料检测到Yr18基因,有55份材料检测到1BL/1RS易位系,分别占被检测材料的1.89%、51.89%。对目前流行条锈菌小种有良好抗性且表现慢锈性的Yr18基因在甘肃天水小麦育种中的利用率较低,而1BL/1RS易位系的利用率仍然较高。品系15-16H307和07-144-2-1-1-1同时检测到1BL/1RS易位系和Yr18基因,建议在甘肃天水小麦抗条锈病育种中合理应用。 相似文献
133.
考虑常利率及通货膨胀下有扰动的双复合Poisson-Geometric过程的两险种风险模型,运用鞅方法得到破产概率满足的Lundberg不等式和一般公式,当保费和索赔服从指数分布和混合指数分布时,得到破产概率的精确表达式。 相似文献
134.
135.
长梗润楠扦插生根对IBA、NAA和IAA的响应 总被引:2,自引:0,他引:2
长梗润楠(Machilus longipedicellata)是西南地区的特有树种之一,也是优良的绿化树种。以长梗润楠为试材,采用U_7(7~6)方法,研究了IBA、NAA、IAA对长梗润楠扦插生根的影响。结果表明:扦插9个月时,平均愈伤组织产生率、生根率、一级根数、一级根长和一级根直径分别为78.9%~85.6%、84.5%~92.2%、2.7~3.7条·株~-1、9.7~14.6cm和1.22~1.58mm;0.75g·L~(-1) IAA+0.4g·L~(-1) IBA组合的生根率、平均一级根数、一级根直径和根长分别达85.5%、3.5条·株-1、1.58mm和13.5cm,为生根性状综合指标较优的处理组合。穗条的生根率与愈伤组织产生率间呈极显著正相关(P≈0.0000.01),二者的相关模型为Y=26.846+0.629 X(R2=0.506,R2Adj=0.484)。 相似文献
136.
RAN Xu-hua CAO Si ZHANG Yao WEI Xiao-man WEN Xiao-bo NI Hong-bo ZHU Zhan-bo 《中国畜牧兽医》2015,42(5):1104-1109
Rotavirus is a major cause of acute diarrhea in both many kinds of young animals and children under 5 years old.Rotavirus NSP1, a 55 ku RNA binding protein, is the product of gene 5, which can subvert innate immune responses and be one of virulent determinant factors.According to the sequence in GenBank, specific primers targeting to NSP1 gene were designed and the gene was amplified by RT-PCR, following by being cloned into the pET-28a(+) vector.It showed that the full length of NSP1 gene was 1 473 bp, encoding 491 amino acids.The NSP1 shared the highest identity with WC3 strain.The recombinant protein was induced in E.coli Rosetta(DE3) by IPTG and was analyzed by SDS-PAGE and Western blotting.The results revealed that NSP1 recombinant protein existed in the form of inclusion body with the molecular weight of 55 ku.The purified recombinant protein could be recognized by His-tag antibody.This study laid the foundation for further research on the relationship between the intracytoplasmic location of NSP1 protein and its activity. 相似文献
137.
139.
超级稻是巴马县近年来主推的重要水稻品系之一。由于其生长旺盛,在生育中后期长势浓郁,稻秆基部易遭受纹枯病的侵染危害。对该县甲篆乡等乡镇超级稻纹枯病的发生进行调查,分析其发病的主要原因,并提出有效的防治对策,以供稻田生产参考。 相似文献
140.