全文获取类型
收费全文 | 152篇 |
免费 | 11篇 |
国内免费 | 60篇 |
专业分类
林业 | 3篇 |
农学 | 45篇 |
基础科学 | 3篇 |
6篇 | |
综合类 | 80篇 |
农作物 | 69篇 |
畜牧兽医 | 12篇 |
园艺 | 1篇 |
植物保护 | 4篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 6篇 |
2009年 | 13篇 |
2008年 | 17篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
排序方式: 共有223条查询结果,搜索用时 15 毫秒
51.
52.
[目的]选出高产、高抗、综合农艺性状好的耐密玉米(Zea mays L.)新组合。[方法]运用间比法试验设计,研究4个耐密玉米新组合产量及其相关性状。[结果]新组合的平均产量与增幅的大小顺序一样均为PJX-7113×hg-1hg-1×110hg-1×139;千粒重与增幅的大小顺序一样均为PJX-7113×hg-1hg-1×139hg-1×110;穗长在17.07~19.92 cm;秃尖长在1.15~1.84 cm;穗行数在13.73~17.43行;行粒数在36.28~40.05行;穗粗在4.95~5.38 cm。[结论]综合考虑,在该试验条件下,新组合PJX-7的产量最高,综合性状较好,该组合审定后,适合在当地大面积推广种植。 相似文献
53.
The activities of RuBPC and C4 photosynthetic enzymes in ear and flag leaf blade were examinedin wheat. The results showed that photosynthesis of ear was less sensitive to soil drought than that of flag leaf,and decrease of CO2 assimilation in flag leaf blade with water stress was more than that in ear. Compared withflag leaf, ear organs(awn, glume and lemma) had higher C4 enzyme activities and lower RuBPC activity. Un-der moderate water-stress, the increase of C4 enzyme activities was induced, and the increase was higher in earthan in flag leaf. Under severe water-stress, relatively higher C4 enzyme activities were still maintained in ear,rather than that in flag leaf. It suggests that high activities of C4 enzymes in ear may contribute to its high tol-erance of photosynthesis to water-stress. 相似文献
54.
55.
生物有机肥对鲜食玉米产量、土壤养分及微生物的影响 总被引:1,自引:0,他引:1
为了研究生物有机肥对鲜食玉米的产量、土壤养分及微生物数量的影响,以鲜食玉米'中科糯甜99'为试材,采用田间试验的方法,调查了施用生物有机肥后鲜食玉米的农艺性状和产量,检测了土壤的养分含量和微生物数量.结果表明,施用生物有机肥显著降低了土壤的pH,分别比对照减少4.9%~6.8%;提高了土壤的养分含量,有机质、碱解氮、有... 相似文献
56.
玉米株高整齐度与穗部性状的相关性分析 总被引:3,自引:0,他引:3
对不同密度下的玉米株高整齐度与德部性状的相关分析表明,玉米株高整齐度随密度的提高而降低,株高整齐度与穗长、行粒数、穗粒数、单穗重和穗粒重均呈极显著正相关,与秀尖呈极显著负相关,相关程度:行粒数>秃尖>穗长>单穗重>穗粒重>穗位数。生产上可以通过栽培措施的标准化,提高玉米株高整齐度,实现丰产稳产的目的。 相似文献
57.
58.
为了进一步探明玉米丝黑穗病对玉米产量造成的损失程度,对5个感玉米丝黑穗病品种进行发病情况观察及对产量损失影响程度的测定。经2个试验点调查发现,每个品种感病后部分病株都有分化穗的能力,一般分化穗株占病株数0.51%~14.64%,并且分化穗全部在病穗上位叶。其中病株分化穗表现为可授粉穗能够正常结实,并有商品价值;可授粉结实但灌浆不足,无商品价值;可授粉仅有粒型但未能灌浆;分化穗未能授粉等类型。结果表明少量病株分化穗株具有一定的结实能力,病株分化穗株结实产量比病株率减少损失0.13%~1.27%,因此玉米丝黑穗病产量损失率小于发病率。 相似文献
59.
60.
Inter-plant competition for resources in maize crops grown under contrasting nitrogen supply and density: Variability in plant and ear growth 总被引:2,自引:0,他引:2
Increased plant population density in irrigated and fertilized maize crops enhances plant-to-plant variability since early vegetative stages, because the most suppressed individuals of the stand intercept less radiation per unit leaf area than the dominant ones (i.e. a size-asymmetric competition for light). Contrarily, a size-symmetric competition has been proposed for the acquisition of soil resources in a plant community (e.g. N capture per unit root length is similar among plants of different size). Hence, N fertilization effect on the variability of maize plants would depend on the initial plant-to-plant variability or on that promoted by a high plant population density. Two maize hybrids with contrasting tolerance to crowding (tolerant AX820 and intolerant AX877) were cultivated under different combinations of stand densities (6, 9 and 12 plants m−2) and N supplies (0 and 200 kg N ha−1) without water restrictions. Variability in plant growth rate among plants was computed along the cycle, especially after fertilizer was applied (i.e. the early reproductive period; PGRER) and during the critical period around silking (PGRCP). Plant-to-plant variability in biomass partitioning to the ear (partition index; PI), ear growth rate during the critical period (EGRCP) and kernel number per plant (KNP) was also established. Reduced N supply increased the coefficient of variation (CV) of PGRER, PGRCP, EGRCP and KNP (0.05 < P < 0.10). The CVs of PGRCP, PI, EGRCP and KNP augmented (0.001 < P < 0.10) at the highest stand density. The CVs of PGRER, PGRCP, PI and KNP were larger for hybrid AX877 than for hybrid AX820 (0.001 < P < 0.10). N fertilization smoothed the initial plant-to-plant variability, but the extent of this benefit in a maize crop is genotype dependent; it was much larger in the hybrid tolerant to crowding stress than in the intolerant one. For the latter, the variability held during the critical period around silking and produced a high CV of KNP. 相似文献