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101.
杂交狼尾草生育特性研究 总被引:14,自引:2,他引:12
研究了杭州生态条件下移栽杂交狼尾草的生育特性,试验表明,杂交狼尾草平均每叶展开需积温前3叶为75.9℃、9叶至20叶为62.3℃;4叶1心开始分蘖;单株干物质积累高峰期出现地拔节后,茎叶粗蛋白含量随生育期而下降;重施拔节肥是高产优质的关键,根茎安全越冬应保持地温在10℃以上。 相似文献
102.
波德代肉羊与甘肃高山细毛羊杂交试验 总被引:1,自引:1,他引:0
引入肉羊品种波德代,观察其在高寒牧区的适应性,并做为父本,以天祝县毛肉兼用型甘肃高山细毛羊为母本,进行杂交改良,经对波细F1代的测定,在相同饲养管理条件下,波细F1代在初生重、1月龄、4月龄重比同龄细羔分别高1.16 kg、2.33 kg、6.80 kg,差异显著(P〈0.005)。对4月龄羔羊屠宰测定,波细F1代的宰前活重、胴体重比同龄细羔分别高6.86 kg、5.39 kg,差异极显著(P〈0.005),屠宰率提高了10个百分比。 相似文献
103.
利用杂种一代自由授粉的种子造林,所产生的杂种二代具有明显的增产能力。7年生的落叶松高生长比对照平均增加39.6%,其保存率也普遍高于对照。杂种二代与杂种一代一样具有较强的抗寒能力和适应性。充分利用杂种一代,可节省大量的人力、物力,促进营林生产的发展。 相似文献
104.
105.
贵州省主要自育杂交水稻超高产潜力研究 总被引:1,自引:0,他引:1
[目的]为提高水稻的单产水平提供理论依据。[方法]以水稻品种黔优88、益农1号和黔南优2058、Ⅱ优838(对照)为供试材料,研究了不同品种的高产特性。[结果]黔优88、益农1号和黔南优2058的产量分别为12990.0、12823.5和12460.5kg/hm^2,分别比对照Ⅱ优838增产20.0%、18.5%和15.1%。与对照Ⅱ优838相比,黔优88、益农1号和黔南优2058的有效穗增加15.1%、24.5%和3.5%;千粒重分别高2.7%、4.2%和11.4%;总颖花数分别增加10.5%、11.7%和8.3%,生物产量分别高187.0、98.0和220.0g/m^2。黔优88和益农1号库容量分别比Ⅱ优838大13.4%和16.4%。上述3个品种的干物质生产优势表现在中期和后期。[结论]黔优88、益农1号和黔南优2058的平均产量达到12757.5kg/hm^2。 相似文献
106.
107.
针对转基因741杨硬枝扦插难生根的特性,将组织培养及多种扦插繁殖技术有机结合在一起,建立了转基因741杨综合配套育苗体系,提出了适合无性繁殖的“遮阴间歇喷雾扦插”和“移棚不移苗扦插繁殖”育苗方法。转基因741杨组培快繁中,初始启动培养基为MS 6-BA1.0mg/L NAA0.1ms/L,嫩茎增殖培养基为MS 6-BA0.3~1.0mg/L IBA0~0.3mg/L,茎尖生根培养基为1/2MS 0.3IBA 1.5%蔗糖。不同月份嫩枝扦插培养的苗木中,5月份扦插的嫩枝生长较快,但苗木间分化程度较高;8月份扦插的嫩枝生长相对较慢,但苗木的分化程度低,生长整齐。不同月份苗木移栽后,生长节律相同,经过1a生长,不同月份间苗木生长差异不明显,5月份扦插的苗木生长略优于其他月份扦插的苗木。 相似文献
108.
The effects of nitrogen (N) and phosphorus (P) rates, P source, and method of P application were tested on growth and nutrition of four clones of hybrid poplar (Populus trichocarpa Torr. & Gray×P. deltoides Bartr. ex Marsh or P. trichocarpa×P. maximowiczii A. Henry) in a plantation on Vancouver Island. Treatments were applied shortly after planting. Nitrogen (0, 500kgNha–1) was supplied as ammonium sulfate (AS); half of the AS was added at the start of the second growing season. Phosphorus (0, 100, 200kgPha–1) was supplied as triple super phosphate (TSP), rock phosphate (RP), or diammonium phosphate (DAP) and banded or broadcast. Over four growing seasons, stem volumes increased with AS and P additions. The effects of AS and P each were greatest when the other was also added. Volume was greater when P was applied at 100kgha–1 than in the P control and did not significantly increase further at 200kgPha–1. Phosphorus additions were more effective when added as TSP or DAP than when added as RP, but only in P100 and when banded. Banding increased volume when P was applied at 200kgha–1, but increases were significant only for DAP fertilized trees. Roto-tilling associated with the banding treatment also increased volume when AS and P were not added. Rankings of clones with respect to stem volume varied with N supply and changed over time. 相似文献
109.
This study develops an analytical method that enables the simulation of the deformation of timber-framed plywood panel dome
structures, of which strength is largely governed by the rigidity of joints. A hybrid truss structure model was employed to
analyze this structure. In this model, we aimed to incorporate the mechanical properties of bolted and nailed joints, which
were employed to build the structures, although the present investigation focused on the deformation characteristics of a
dome in which the panel elements were connected mutually by elastic springs. The results of the theoretical analysis are compared
with those obtained by experiments. The simulated results were found to be in good agreement with the results of the experiments
under similar loading conditions. 相似文献
110.
Takaaki Fujimoto Kazuhito Kita Kazuko Uchiyama Makoto Kuromaru Hisashi Akutsu Kazuyuki Oda 《Journal of Forest Research》2006,11(3):157-163
Age trends in variance components and heritability of overall wood density, earlywood and latewood density, and latewood proportion
were investigated in 29-year-old trees of 19 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F1. The age–age correlation and optimum selection age for these traits were also estimated and genetic and phenotypic correlations
between wood density and radial growth rate were calculated for each growth ring. Intraring wood density data were obtained
using X-ray densitometry. The coefficient of additive genetic variance was stable over all ages, whereas the coefficient of
environmental variances gradually decreased with increasing age, resulting in increases in heritability estimates with age
for overall density. The latewood proportion had the highest heritability estimates at all ages, ranging from 0.44 to 0.66.
Overall density and its various components at 28 years of age showed strong genetic correlations with their respective traits
at all younger ages. Optimum selection ages for the wood density traits ranged from 8 to 14 years, at which point maximum
gain efficiencies per year were obtained. There were negative correlations between wood density and radial growth rate at
early ages, although these relationships tended to be weaker with increasing age. These results suggest that selection at
a young age is effective for wood density, but particular care must be taken in selecting trees with an improved radial growth
rate because rapid growth will result in a low-density wood product, especially in the early growth period. 相似文献