全文获取类型
收费全文 | 1253篇 |
免费 | 38篇 |
国内免费 | 33篇 |
专业分类
林业 | 49篇 |
农学 | 72篇 |
基础科学 | 23篇 |
41篇 | |
综合类 | 437篇 |
农作物 | 12篇 |
水产渔业 | 12篇 |
畜牧兽医 | 613篇 |
园艺 | 32篇 |
植物保护 | 33篇 |
出版年
2024年 | 4篇 |
2023年 | 12篇 |
2022年 | 33篇 |
2021年 | 33篇 |
2020年 | 22篇 |
2019年 | 34篇 |
2018年 | 6篇 |
2017年 | 33篇 |
2016年 | 48篇 |
2015年 | 34篇 |
2014年 | 65篇 |
2013年 | 47篇 |
2012年 | 87篇 |
2011年 | 103篇 |
2010年 | 72篇 |
2009年 | 75篇 |
2008年 | 53篇 |
2007年 | 84篇 |
2006年 | 54篇 |
2005年 | 49篇 |
2004年 | 31篇 |
2003年 | 35篇 |
2002年 | 39篇 |
2001年 | 43篇 |
2000年 | 40篇 |
1999年 | 24篇 |
1998年 | 25篇 |
1997年 | 25篇 |
1996年 | 20篇 |
1995年 | 12篇 |
1994年 | 29篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 4篇 |
排序方式: 共有1324条查询结果,搜索用时 562 毫秒
101.
Summary Electrophoretic variants of peroxidase in mulberry (Morus spp.) were demonstrated by thin-layer gel isoelectric focusing. Of these variants, three isozyme band groups were found to be controlled by codominant alleles at a single locus. The gene symbol Px
1 was given to this locus, with alleles Px
1
1 and Px
1
2 assigned to the A6-A7-A8 and A7-A8-A9 band groups, respectively. The A6-A7-A8-A9 band group proved to be controlled by the Px
1
1 and Px
1
2 heterozygote.Additional experiments showed that among the three banding types, there were no statistically significant differences in leaf blade length, leaf blade width, length-width ratio of leaf blade, internode length, phyllotaxis, leaf shape, tree vigor and resistance to powdery mildew, but there were significant differences in leafstalk length. 相似文献
102.
103.
用聚丙烯酰胺等电聚焦电泳,分析了不同血统和化性的九个品种的家蚕(Bombyxmori)血淋巴酯酶同工酶(EST).结果表明,所有的品种五龄盛食期幼虫都呈现相似的酶谱,可区分为四个区带(ESTⅠ、Ⅱ、Ⅲ和Ⅳ),共出现18条带,带的数目和酶活强度随品种而异.在五个品种中的Ⅲ-3及四个品种中的Ⅱ-2出现了伴性现象,Ⅲ-3伴随雄性、Ⅱ-2伴随雌性出现. 相似文献
104.
A line × tester analysis was carried out in mulberry (Morus spp.) to determine the genetic interaction in the expression of
various quantitative characters including leaf yield. Eight clonal varieties were selected, 3 of them were designated as lines
(♀) viz. Berhampore-1, China white and MS-5 and 5 of them were called as testers (♂) viz. Mandalaya, Kosen, Assamjati, MS-1
and Kajli. Combining ability studies were conducted on these parents along with their F1 hybrids for the variables laminar index, growth rate, weight of 100 dry leaves, number of primary branches per plant, plant
height, nodal distance, leaf-twig ratio, aerial biomass, moisture content, moisture retention capacity and leaf yield. Broad
genetic variability was observed among the genotypes. The ratio of General Combining Ability (GCA) and Specific Combining
Ability (SCA) indicated the predominance of non-additive genes in mulberry. While China white (female) and MS-1 (male) were
the best general combiners among the parents, Berhampore-1 × Kajli was the best cross for leaf yield. Results suggest that
selective crossing followed by proper screening may be the best approach for breeding of high yielding varieties in mulberry.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
105.
在含白糖、石膏各1%,分别以桑枝粒,桑枝屑和蚕沙为基础,加与不加麦麸,或以蚕沙代替麦麸的不同8种菌种培养基上培养,除加入0.5%尿素的明显表现不良影响外,其余均能正常生长,尤以在蚕沙培养基中生长最快。表明蚕沙可以代替麦麸使用。桑枝屑袋栽毛木耳,一潮耳片的生物学效率为47.8%~60.8%。凤尾菇在含10%麦麸桑枝培养基上的生物学效率是64.2%,在100%桑枝屑是58.8%,在含桑枝屑30%、桑枝粒 70%是58.2%,在含稻草 60%与40%的桑枝屑生料袋栽时生物学效率分别是43.3%与31.7%,表明加入稻草混合反而效果不好。 相似文献
106.
超微粉碎对桑叶粉理化性质的影响 总被引:1,自引:1,他引:1
为拓展超微粉碎技术在食品添加剂和药品开发中应用,以桑叶为原料,分别对桑叶粗粉进行干法超微粉碎2 、4、6、8 h,得到4种不同粒径大小的桑叶超微粉,并对桑叶粗粉与4种超微粉的理化性质进行比较。研究结果表明,超微粉碎能明显减小桑叶粗粉的颗粒粒径(P<0.05),随着超微粉碎时间的增加,超微粉的粒径减小,粉体的粒径分布范围变窄,比表面积和体积密度显著增加(P<0.05),休止角、滑角和膨胀性显著降低(P<0.05),水溶性/持水力、持油力、蛋白质的水溶性和多糖的水溶解性均有不同程度的增加,但多酚含量变化不显著(P>0.05)。扫描电镜结果显示,粗粉经超微粉碎后,其颗粒呈零散的分布形态。说明超微粉碎可改善桑叶粉的部分理化性质,可将这些性质应用于食品添加剂和常规食品开发与加工中。所得研究结果将为超微粉碎技术在桑叶食品中工业化应用提供数据支持和理论依据。 相似文献
107.
108.
氮钾肥配合施用对桑叶产量品质及蚕茧质量的影响 总被引:3,自引:0,他引:3
通过连续4年田间施肥试验和一季养蚕试验,研究了氮肥和钾肥配合施用对桑叶产量、品质及相应桑叶喂饲家蚕对蚕生长及蚕茧品质的影响。结果表明,桑园施用氮钾肥显著提高桑叶产量,在氮钾肥各养分配比中,以高氮高钾处理(N450K300)的产量最高,比N0K0处理年均增产35.2%,与其他各处理产量差异显著。桑叶品质分析结果表明,桑叶中必需氨基酸、氨基酸总量、粗蛋白、油脂含量随氮肥用量增加而提高,但单施氮肥会对蛋氨酸和油脂含量产生负面影响;施钾导致糖分含量下降,其他品质参数值随钾肥施用而提高,氮钾肥配合施用具有提高桑叶品质的作用。养蚕结果表明,桑园增施氮钾肥生产出的桑叶,有助于降低蚕茧的死笼率、具有提高全茧量和茧层率及提高蚕茧产量的作用。蚕茧上茧率、茧丝长、解舒率和茧丝净度随着钾肥用量的增加而提高,在施钾基础上增加氮肥用量有提高蚕茧品质的作用,但不施钾只施氮肥对上茧率有负面影响,说明氮钾肥配合施用能促进蚕茧质量的提高。 相似文献
109.
ZHAO Yan-Wen J. D. BEATON CAO Zhi-Hong A. M. HENDERSON HU Zheng-Yi XU Cheng-Kai 《土壤圈》2001,11(1):63-66
A 40-day gnotobiotic microcosm experiment was carried out to quantify the effect of bacterial-feeding nematode on plat growth and nutrient absorption.The results showed that inoculation of bacterial-feeding nematode Protorhabditis sp.stimulated the growth of wheat (Triticum aestivum) and the uptake of N.By the end of the 40-day incubation wheat biomass and N uptake in the treatment with nematode and bacteria (Pseudomonas sp.)increased by 6.5% and 5.9%,respectively,compared with bacteria alone treatment.The presence of nematode mainly accelerated the growth of aboveground of wheat,while it slightly inhibited the root development.There was little difference in plant tissue N concentration between treatments.P concentration and uptake of wheat,however,were generally reduced by nematode, It appears that the enhancement of plant growth and nitrogen uptake is attributed to the enhancement of nitrogen mineraliztion induced by nematode feeding on bacteria,and the reduction of phosphorous uptake is the result of ewak root status and comptetition by bacteria immobilzation. 相似文献
110.