全文获取类型
收费全文 | 101篇 |
免费 | 2篇 |
专业分类
林业 | 2篇 |
4篇 | |
综合类 | 38篇 |
农作物 | 2篇 |
水产渔业 | 2篇 |
畜牧兽医 | 17篇 |
园艺 | 1篇 |
植物保护 | 37篇 |
出版年
2020年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2009年 | 3篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2005年 | 1篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 5篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1966年 | 4篇 |
1957年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有103条查询结果,搜索用时 453 毫秒
91.
92.
93.
In an effort to expand the spectrum of larvicides effective against the pea leafminer,Liriomyza huidobrensis (Blanchard), we studied the effects of a neem-based insecticide (Neemix-45) on the development of the leafminer under laboratory conditions. Bean plants were treated with a soil drench of 1, 5, 10 or 25 ppm azadirachtin or by dipping leaves in 1 or 15 ppm azadirachtin at various times before or during the development of the leafminer. Treating the plants with the neem insecticide before exposure to egg-laying adults had a greater effect on inhibiting the development of pupae and adult eclosion than treatment at the 1st-instar larval stage. The systemic effects from a soil drench had a greater adverse effect on pupation and adult eclosion than leaf dipping. Drenching plants with 1 ppm azadirachtin 24 h before exposure to adults had a greater effect (0% adult eclosion) than leaf dipping at the same time period and concentration (15. 6% adult eclosion). Similar results were obtained when drenching plants infested with lst-instar larvae with 1 ppm azadirachtin (11. 7% eclosion)vs dipping leaves at the same time period and concentration (44. 7% eclosion). 相似文献
94.
Arthur J. Horowitz 《Journal of Soils and Sediments》2009,9(4):342-363
Background, aim, and scope The City of Atlanta, Georgia (COA) is part of the ninth largest metropolitan area in the USA and one of the fastest growing
(e.g., >24% between 2000 and 2007). Since 2003, the US Geological Survey has been operating an extensive long-term water-quantity
and water-quality monitoring network for the COA. The experience gained in operating this network has provided insights into
the challenges as well as some solutions associated with determining urban effects on water quality, especially in terms of
estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients.
Discussion and findings The majority (>90%) of the annual fluxes of suspended sediment and discharge (>60%) from the COA occur in conjunction with
stormflow. Typically, stormflow averages ≤20% of the year. Normally, annual flux calculations employ a daily time-step; however,
due to the “flashy” nature of the COA’s streams, this approach can produce substantial underestimates (from 25% to 64%). Greater
accuracy requires time-steps as short as every 2 to 3 h. The annual fluxes of ≥75% of trace elements (e.g., Cu, Pb, Zn), major
elements (e.g., Fe, Al), and total P occur in association with suspended sediment; in turn, ≥90% of the transport of these
constituents occurs in conjunction with stormflow. With the possible exception of nitrogen, baseflow sediment-associated and
both baseflow and stormflow dissolved contributions represent relatively insignificant portions of the total annual load;
hence, nonpoint (diffuse) sources are the dominant contributors to the fluxes of almost all of these constituents. 相似文献
95.
The relative phytotoxicity of four soil-applied herbicides, benzthiazuron, cycloate, delachlor, and pyrazon, used for sugar beet (Beta vulgaris L.), was tested on a dilution series of peat, Newe Ya’ar clay soil and Hamadia calcareous clay soil mixed with sand, and of Newe Ya’ar clay soil mixed with lime. The phytotoxicity was assessed with oats (Avena sativa L. cv. Mulga). Cycloate was the most potent herbicide of the four, except in soils with high organic matter ( ?11%), where delachlor was more active. Benzthiazuron was the least phytotoxic herbicide in the peat + sand mixtures, but it was more active than pyrazon in lighter soils of the Newe Ya’ar series. The addition of sand to the peat and the soils increased the phytotoxicity of all herbicides. The addition of lime to Newe Ya’ar clay soil decreased the phytotoxicity of benzthiazuron and pyrazon but not of delachlor. 相似文献
96.
The phytotoxicity of benefin, as assessed by sorghum on various soils and soil mixtures, was significantly correlated with the organic matter content but not with the clay or lime content of the soils. After 1 month of incubation no significant activity remained from 2 ppm benefin, and after 2 months only slight activity remained from 4 ppm. Benefin was less persistent than trifluralin and more persistent than nitralin. 相似文献
97.
Horowitz ML Cohen ND Takai S Becu T Chaffin MK Chu KK Magdesian KG Martens RJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(3):171-175
The distributions of the incubation periods for infectious and neoplastic diseases originating from point-source exposures, and for genetic diseases, follow a lognormal distribution (Sartwell's model). Conversely, incubation periods in propagated outbreaks and diseases with strong environmental components do not follow a lognormal distribution. In this study Sartwell's model was applied to the age at onset and age at death of foals with Rhodococcus equi pneumonia. The age at onset of clinical signs and age at death were compiled for 107 foals that had been diagnosed with R. equi pneumonia at breeding farms in Argentina and Japan. For each outcome (disease and death), these data followed a lognormal distribution. A group of 115 foals with colic from the University of California were used as a comparison group. The age at onset of clinical signs for these foals did not follow a lognormal distribution. These results were consistent with the hypothesis that foals are infected with R. equi during the 1st several days of life, similar to a point-source exposure. 相似文献
98.
Ofri R Steinmetz A Thielebein J Horowitz IH Oechtering G Kass PH 《Veterinary journal (London, England : 1997)》2008,177(1):124-129
The aim of this study was to conduct a detailed analysis of the relationship between age and intraocular pressure (IOP) in lions. Tonometry was conducted in 33 lions aged 5 days to 80 months. Age was significantly associated with IOP (P<0.005). Mean IOP was 12.8+/- and 23.9+/-4.1 mmHg in lions < or =1 year old and >1 year old, respectively. IOP linearly rose with age during the first 20 months of life, plateaued until approximately 40 months, and then gradually declined (r=0.85). Age-related changes in IOP were highly correlated with ultrasonographic measurements of intraocular dimensions (r > or = 0.72), and may be a determinant factor in developmental ocular growth. The dramatic rise in IOP of young lions is similar to that observed in children, but has not been previously demonstrated in animals. Significant IOP differences between lion sub-species were also demonstrated. 相似文献
99.
100.