全文获取类型
收费全文 | 3679篇 |
免费 | 242篇 |
国内免费 | 346篇 |
专业分类
林业 | 390篇 |
农学 | 432篇 |
基础科学 | 245篇 |
457篇 | |
综合类 | 1424篇 |
农作物 | 250篇 |
水产渔业 | 134篇 |
畜牧兽医 | 554篇 |
园艺 | 182篇 |
植物保护 | 199篇 |
出版年
2024年 | 12篇 |
2023年 | 43篇 |
2022年 | 148篇 |
2021年 | 177篇 |
2020年 | 159篇 |
2019年 | 148篇 |
2018年 | 100篇 |
2017年 | 192篇 |
2016年 | 115篇 |
2015年 | 149篇 |
2014年 | 185篇 |
2013年 | 222篇 |
2012年 | 274篇 |
2011年 | 282篇 |
2010年 | 285篇 |
2009年 | 246篇 |
2008年 | 247篇 |
2007年 | 222篇 |
2006年 | 181篇 |
2005年 | 151篇 |
2004年 | 105篇 |
2003年 | 65篇 |
2002年 | 68篇 |
2001年 | 63篇 |
2000年 | 54篇 |
1999年 | 65篇 |
1998年 | 44篇 |
1997年 | 38篇 |
1996年 | 38篇 |
1995年 | 33篇 |
1994年 | 19篇 |
1993年 | 29篇 |
1992年 | 20篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 19篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1962年 | 1篇 |
1956年 | 1篇 |
1948年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有4267条查询结果,搜索用时 453 毫秒
91.
92.
本研究证明Phytophthora parasitica是我国柑桔脚腐病病原菌之一;高温多雨有利本病盛发;据对51个柑桔种质资源抗病性测定结果表明:枳、枳橙、枳柚、大叶金豆、酸橙等19个种类或品种对本病具有高抗或抗病,福桔、尤力克柠檬等14种材料为感病或重感病型,其余18个为中抗或中感型;防治试验证明,瑞毒霉(metalaxyl)、乙磷铝(phosethyl-Al)、甲霜铝铜(①metalaxyl②aluminum tris)等杀菌剂对病树有明显的治疗作用。利用抗病砧木靠接对缓解该病危害具有事半功倍的效果。 相似文献
93.
Y. Wang J. Ren L. Lan X. Yan X. Huang Q. Peng H. Tang B. Zhang H. Ji & L. Huang 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2007,124(4):225-229
Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus. 相似文献
94.
二甲基亚砜(DMSO)、丙二醇(PROH)、乙二醇(EG)和甘油(GL)4种冷冻保护剂程序化冷冻牛GV期卵母细胞的结果表明,EG和PROH的保护效果比GL和DMSO好。4种不同冷冻方法冷冻保存牛GV期卵母细胞,比较解冻后卵母细胞的体外成熟率、受精后卵裂率。结果表明,在程序化冷冻法与细管玻璃化法(Straw)之间的差异不显著(P>0.05),在开放式拉管法(OPS)与毛细玻管法(GMP)之间的差异不显著(P>0.05);但OPS和GMP与程序化冷冻法和Straw之间的差异极显著(P<0.01)。玻璃化冷冻效果优于程序化冷冻。说明GMP和OPS玻璃化冷冻优于Straw玻璃化冷冻。说明可以采用GMP方法冷冻保存牛GV期卵母细胞。 相似文献
95.
蓝荣庚 《广东畜牧兽医科技》2006,31(1):35-36
鸡绿脓杆菌病是由假单胞菌属绿脓杆菌引起雏鸡和青年鸡的一种局部或全身化脓性感染或败血症。刚出壳的雏鸡发生绿脓杆菌病可引起雏鸡大批死亡,造成毁灭性损失。笔者在近十年来从事禽病诊治服务过程中发现雏鸡(10日龄内)发病率呈上升趋势。现就一养鸡户所养雏鸡发病诊治过程简述 相似文献
96.
Kunimasa Kawabe Nguyen Thi Ngoc Truc Bui Thi Ngoc Lan Le Thi Thu Hong Masatoshi Onuki 《Journal of General Plant Pathology》2006,72(6):355-359
A quantification system for huanglongbing pathogen using a competitive polymerase chain reaction method and image-analyzing
software were developed to obtain precise results. Significant differences in the quantity of pathogen were thus determined
in leaves of two citrus cultivars commonly cultivated in southern Vietnam. Less pathogen-related DNA was detected from the
tissue of citrus cultivars that are believed to be more tolerant than susceptible cultivars. The quantification system will
be used in studies on pathogen proliferation and movement inside citrus tissue. 相似文献
97.
98.
Sung Jae Shin Seung Won Shin Mi Lan Kang Deog Yong Lee Moon-Sik Yang Yong-Suk Jang Han Sang Yoo 《Journal of veterinary science (Suw?n-si, Korea)》2007,8(4):383-392
We previously induced protective immune response by oral immunization with yeast expressing the ApxIIA antigen. The ApxI antigen is also an important factor in the protection against Actinobacillus pleuropneumoniae serotype 5 infection; therefore, the protective immunity in mice following oral immunization with Saccharomyces cerevisiae expressing either ApxIA (group C) or ApxIIA (group D) alone or both (group E) was compared with that in two control groups (group A and B). The immunogenicity of the rApxIA antigen derived from the yeast was confirmed by a high survival rate and an ApxIA-specific IgG antibody response (p < 0.01). The highest systemic (IgG) and local (IgA) humoral immune responses to ApxIA and ApxIIA were detected in group E after the third immunization (p < 0.05). The levels of IL-1β and IL-6 after challenge with an A. pleuropneumoniae field isolate did not change significantly in the vaccinated groups. The level of TNF-α increased in a time-dependent manner in group E but was not significantly different after the challenge. After the challenge, the mice in group E had a significantly lower infectious burden and a higher level of protection than the mice in the other groups (p < 0.05). The survival rate in each group was closely correlated to the immune response and histopathological observations in the lung following the challenge. These results suggested that immunity to the ApxIA antigen is required for optimal protection. 相似文献
99.
100.
邻烯丙基苯酚对植物病原真菌抑制机理初探 总被引:5,自引:1,他引:5
用含毒介质培养法测定了邻烯丙基苯酚(银果)对番茄灰霉病菌Botrytis cinerea、苹果腐烂病菌Valsa mali和小麦纹枯病菌Rhizoctonia cerealis的影响。通过培养观察发现,邻烯丙基苯酚可抑制番茄灰霉病菌分生孢子的产生、促进灰霉病菌菌核的形成及苹果腐烂病菌子囊壳的形成。光学显微观察表明:用50μg/mL的邻烯丙基苯酚处理番茄灰霉病菌菌丝后,菌丝伸长缓慢,分支间距缩短,分生孢子形成受到抑制。电镜观察表明:经邻烯丙基苯酚处理后,番茄灰霉病菌菌丝内液泡增多,苹果腐烂病菌菌丝细胞壁增厚,小麦纹枯病菌菌丝中内质网处泡囊增多。 相似文献