全文获取类型
收费全文 | 665篇 |
免费 | 64篇 |
专业分类
林业 | 16篇 |
农学 | 8篇 |
基础科学 | 4篇 |
82篇 | |
综合类 | 134篇 |
农作物 | 26篇 |
水产渔业 | 10篇 |
畜牧兽医 | 354篇 |
园艺 | 7篇 |
植物保护 | 88篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 12篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 30篇 |
2011年 | 39篇 |
2010年 | 17篇 |
2009年 | 15篇 |
2008年 | 30篇 |
2007年 | 41篇 |
2006年 | 37篇 |
2005年 | 18篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 25篇 |
2001年 | 27篇 |
2000年 | 28篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1992年 | 5篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1980年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1974年 | 4篇 |
1972年 | 6篇 |
1971年 | 7篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1967年 | 5篇 |
1966年 | 4篇 |
1963年 | 4篇 |
1955年 | 4篇 |
排序方式: 共有729条查询结果,搜索用时 15 毫秒
611.
612.
Thomas W. Eubank Vijay K. Nandula Krishna N. Reddy Daniel H. Poston David R. Shaw 《Weed Biology and Management》2013,13(4):135-143
Saflufenacil is a new herbicide on the market and its effectiveness on horseweed, several populations of which have evolved resistance to glyphosate, is not clear. In this research, the effect of adjuvants on the control of horseweed with saflufenacil in the field, the effect of the interaction between glyphosate and saflufenacil on glyphosate‐resistant and glyphosate‐susceptible horseweed and the patterns of uptake and translocation of glyphosate applied alone and in combination with saflufenacil in horseweed were evaluated. The addition of methylated seed oil to saflufenacil provided the best control of horseweed, with crop oil concentrate being intermediate in effect and non‐ionic surfactant ranking as the least‐effective adjuvant. The interaction between glyphosate and saflufenacil was additive with regards to the control of glyposate‐resistant horseweed. The glyphosate‐susceptible horseweed population absorbed 6–13% more 14C‐glyphosate than the glyphosate‐resistant population. The addition of saflufenacil reduced 14C‐glyphosate translocation in both the glyphosate‐resistant and the glyphosate‐susceptible horseweed populations by at least 6%; however, due to the exceptional efficacy of saflufenacil, these reductions did not reduce the level of control. Saflufenacil holds great potential as an alternative control option for glyphosate‐resistant horseweed and is a valuable tool in the management of resistant weeds. 相似文献
613.
614.
F E Jirjis S L Noll D A Halvorson K V Nagaraja D P Shaw 《Journal of veterinary diagnostic investigation》2001,13(1):13-16
An immunohistochemical staining technique (IHC) was developed to detect avian pneumovirus (APV) antigen in formalin-fixed, paraffin-embedded tissue sections using streptavidin-biotin immunoperoxidase staining. Samples of nasal turbinates and infraorbital sinuses were collected from 4-week-old poults experimentally inoculated with APV and from older turkeys infected during naturally occurring outbreaks of avian pneumovirus. Tissue was fixed in 10% buffered neutral formalin, embedded in paraffin, sectioned and stained. Inflammatory changes were observed microscopically in the mucosa and submucosa of the nasal turbinates and infraorbital sinuses of both experimentally inoculated poults and naturally infected birds. Viral antigen was detected by IHC in the ciliated epithelial cells of nasal turbinates and infraorbital sinuses. 相似文献
615.
Pathological studies of cheek teeth apical infections in the horse: 3. Quantitative measurements of dentine in apically infected cheek teeth 总被引:2,自引:2,他引:0
Histological measurements of dimensions of primary, regular secondary and irregular secondary dentine, pulp diameter and assessment of the levels of predentine, resting lines and enlarged areas of intertubular dentine were performed in apically infected mandibular and maxillary cheek teeth (CT). These examinations showed significantly reduced regular and irregular secondary dentine thickness in diseased as compared to control CT, with 21/26 infected maxillary CT and 15/18 infected mandibular CT having reduced regular secondary dentine (varying between 27.4% and 89.1% reduced secondary dentine levels compared to age and site matched control CT values). As a result of decreased dentinal deposition, significantly wider pulp horns were present in diseased compared to control CT.No significant differences were found between diseased and control primary dentine thickness in maxillary CT, and minor differences in mandibular CT were not believed to be clinically significant. The significantly reduced presence of predentine and of intertubular dentine and the increased presence of resting lines in diseased compared to control CT confirms that long-term disruption of normal dentine deposition had occurred in many infected CT. 相似文献
616.
617.
618.
619.
620.
R.L. Raper D.W. Reeves J.N. Shaw E. van Santen P.L. Mask 《Soil & Tillage Research》2007,96(1-2):174-181
The negative impacts of soil compaction on crop yields can often be alleviated by subsoiling. However, this subsoiling operation is often conducted at unnecessarily deep depths wasting energy and excessively disturbing surface residue necessary for erosion control and improved soil quality. A corn (Zea mays L.)–cotton (Gossypium hirsutum L.) rotation experiment was conducted over 4 years on a Coastal Plain soil with a hardpan in east-central Alabama to evaluate the potential for site-specific subsoiling (tilling just deep enough to eliminate the hardpan layer) to improve crop yields while conserving energy. Seed cotton yield showed benefits of subsoiling (2342 kg/ha) compared to the no-subsoiling treatment (2059 kg/ha). Averaging over all years of the study, site-specific subsoiling produced cotton yields (2274 kg/ha) statistically equivalent to uniform deep subsoiling at a 45 cm depth (2410 kg/ha) while not excessively disturbing surface soil and residues. Significant reductions in draft force were found for site-specific subsoiling (59% and 35%) as compared to uniform deep subsoiling at a 45 cm depth in shallow depth hardpan plots (25 cm) and medium depth hardpan plots (35 cm), respectively. Calculated fuel use for site-specific subsoiling was found to be reduced by 43% and 27% in the shallow and medium depth hardpan plots, respectively, as compared to uniform deep subsoiling in these same plots. Producers in the Coastal Plains who can determine (or who know) the depth of their root-impeding layer and perform site-specific subsoiling can have comparable cotton yields to traditional uniform depth subsoiling with reduced energy requirements. 相似文献