全文获取类型
收费全文 | 409篇 |
免费 | 5篇 |
国内免费 | 21篇 |
专业分类
林业 | 77篇 |
农学 | 48篇 |
基础科学 | 2篇 |
17篇 | |
综合类 | 139篇 |
农作物 | 41篇 |
水产渔业 | 1篇 |
畜牧兽医 | 17篇 |
园艺 | 89篇 |
植物保护 | 4篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 29篇 |
2011年 | 28篇 |
2010年 | 34篇 |
2009年 | 32篇 |
2008年 | 24篇 |
2007年 | 34篇 |
2006年 | 25篇 |
2005年 | 32篇 |
2004年 | 20篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 1篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有435条查询结果,搜索用时 15 毫秒
31.
东革阿里组织培养初报 总被引:1,自引:0,他引:1
通过对东革阿里不同生长时期的枝条进行离体培养,结果表明:老化的枝条较难进行消毒,当年萌发的新枝条消毒相对易些;能诱导出东革阿里愈伤组织的培养基是MS+6-BA0.5mg/L+NAA0.01mg/L+3%蔗糖。 相似文献
32.
《Plant Production Science》2013,16(3):261-268
AbstractIn the field, plants show better root growth in drying soil than in wet soil. However, the root growth enhancement has not been demonstrated clearly in the laboratory. In this study, the root growth response of wheat seedlings to moderate soil water deficits was characterized quantitatively in an environment-controlled chamber. Germinated seeds of wheat were grown for 15 days in the soil with a water potential ranging from field capacity (FC) to approximately –0.08 MPa. Theleaf area decreased with reduction in soil water potential. By contrast, the root surface area increased upon reduction ofthe soil water potential to –0.04 MPa while it decreased significantly in soil with a water potential of –0.08 MPa. The increase in surface area was obvious in the roots with a diameter of 0.2 to 0.4 mm and larger than 0.7 mm. Root weight increased with the reduction of soil water potential to –0.04 MPa. While specific root length decreased significantly with the reduction of water potential to –0.06 MPa, the specific root surface area did not. Assimilatestransported from shoot might be used in roots to increae the surface area mainly by increasing the diameter rather than the length in response to a moderate soil water deficit in wheat seedlings. This might result from the drought tolerance mechanism of osmotic adjustment in roots. 相似文献
33.
《Scandinavian Journal of Forest Research》2012,27(4):342-353
Tree mortality and growth losses following insect defoliation are poorly documented in Scandinavia. In 1990-1991, Diprion pini (L.) caused extensive defoliation to Scots pine in Lauhanvuori national park and surrounding areas in south-western Finland. Most trees lost all their foliage in 1990. In 1991, the outbreak area was sprayed with diflubenzuron (Dimilin®), except in the national park, where trees were severely defoliated again. No further defoliation occurred in 1992. In spring 1993, sprayed trees had ca 30% foliage, whereas unsprayed trees on average carried less than 10% of full foliage. The latter trees were susceptible to attack by Tomicus piniperda (L.), whereas the former largely escaped beetle attack. Beetle attacks peaked in 1993, and depletion of suitable host trees probably terminated the beetle outbreak in the area. Two years of severe defoliation resulted in substantial tree mortality and growth losses. In spring 1997, these unsprayed stands had suffered a ca. 50% loss in basal area which was mainly because of mortality, and about half of the dead trees had been attacked by T. piniperda. Surviving trees had ca 50% of full foliage, and radial growth had still not recovered. Basal area growth was reduced by 40-70%, depending on the amount of foliage left after the second year of defoliation. In contrast, tree mortality and beetle attack in the sprayed stands were negligible, and these trees had recovered full foliage and radial growth by spring 1997. Thus, one year of total defoliation resulted in an estimated loss in basal area growth of approximately 30% during ca. 5 yrs. In conclusion, the spraying operation was economically justified, as it prevented substantial tree mortality and reduced growth losses. 相似文献
34.
35.
利用重瓣大岩桐叶片诱导再生植株试验 总被引:10,自引:0,他引:10
利用重瓣大岩桐叶片诱导再生植株试验结果表明,采用MS+BA1.5-2.00mg/L NAA0.15-0.20mg/L的培养基配比组合最适宜叶片再生小植株;在相同质量浓度下,用NAA处理好于用IBA处理。 相似文献
36.
37.
L. Krishnamurthy Rachid Serraj C. Tom Hash Abdullah J. Dakheel Belum V. S. Reddy 《Euphytica》2007,156(1-2):15-24
Genetic improvement of salt tolerance is of high importance due to the extent and the constant increase in salt affected areas.
Sorghum [Sorghum bicolor (L.) Moench] has been considered relatively more salt tolerant than maize and has the potential as a grain and fodder crop
for salt affected areas. One hundred sorghum genotypes were screened for salinity tolerance in pots containing Alfisol and
initially irrigated with a 250-mM NaCl solution in a randomized block design with three replications. Subsequently 46 selected
genotypes were assessed in a second trial to confirm their responses to salinity. Substantial variation in shoot biomass ratio
was identified among the genotypes. The performance of genotypes was consistent across experiments. Seven salinity tolerant
and ten salinity sensitive genotypes are reported. Relative shoot lengths of seedlings were genetically correlated to the
shoot biomass ratios at all stages of sampling though the relationships were not close enough to use the trait as a selection
criterion. In general, the whole-plant tolerance to salinity resulted in reduced shoot Na+ concentration. The K+/Na+ and Ca2+/Na+ ratios were also positively related to tolerance but with a lesser r
2. Therefore, it is concluded that genotypic diversity exists for salt tolerance biomass production and that Na+ exclusion from the shoot may be a major mechanism involved in that tolerance. 相似文献
38.
39.
利用POX同工酶测定谷子(粟)品种对黑穗病的抗性 总被引:4,自引:0,他引:4
采用箱栽方法种植 12个抗病性不同的谷子品种 ,分析了芽苗过氧化物酶 (POX)活性及同工酶的变化。结果证明 ,对黑穗病免疫的品种接菌后POX活性平均提高 2 2 8%。越是易感病的品种接菌后POX活性提高得越多。感病品种平均提高 71 6 % ,高感品种平均提高 95 0 %。同工酶酶谱 ,免疫品种接菌后不变 ,越是易感病的品种接菌后酶谱变化越大。二维排序 ,免疫品种接菌与不接菌的两个点落在同一点上或附近 ,d值平均为 3 1。易感病品种的两点相去甚远 ,其中 ,感病品种平均d值 12 2 ;高感品种平均d值 13 2。采用芽苗POX同工酶测定谷子品种抗黑穗病性 ,简便快速 相似文献
40.