全文获取类型
收费全文 | 529篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
林业 | 17篇 |
农学 | 8篇 |
55篇 | |
综合类 | 65篇 |
农作物 | 14篇 |
水产渔业 | 61篇 |
畜牧兽医 | 241篇 |
植物保护 | 77篇 |
出版年
2016年 | 7篇 |
2014年 | 7篇 |
2013年 | 5篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 20篇 |
2009年 | 10篇 |
2008年 | 16篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2002年 | 6篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 14篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1991年 | 19篇 |
1990年 | 7篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1963年 | 5篇 |
1960年 | 5篇 |
1959年 | 9篇 |
1958年 | 18篇 |
1957年 | 11篇 |
1956年 | 14篇 |
1955年 | 6篇 |
1954年 | 9篇 |
1953年 | 7篇 |
1946年 | 7篇 |
排序方式: 共有538条查询结果,搜索用时 968 毫秒
11.
ALLAN E. SMITH 《Weed Research》1982,22(3):137-142
The persistence of [14C]MCPA at a rate equivalent to 1 kg ha?1 was studied under laboratory conditions in a clay loam, heavy clay and sandy loam at 85% of field capacity moisture and 20±1°C both alone and in the presence of tri-allate, trifluralin, tri-allate and trifluralin, malathion, Vitaflow DB, malathion and Vitaflow DB, bromoxynil, bromoxynil and asulam, bromoxynil and difenzoquat, dicamba, dicamba and mecoprop, linuron, MCPB, metribuzin, propanil, TCA, benzoylprop-ethyl, diclofop-methyl, and flamprop-methyl. Except in the soils treated with asulam, the half-lives of [14C]MCPA in all three soil types were similar, being approximately 13±1 days, thus indicating that none of the other chemicals studied adversely affected the soil degradation of MCPA. In the asulam treated soils, the half-lives of the MCPA were about 3 days longer than in non-asulam treated soils; the effect was most marked in the clay loam. 相似文献
12.
13.
14.
15.
Survey and contrast radiographic studies of the cardiovascular and gastrointestinal systems of the American horseshoe crab (Limulus polyphemus) were undertaken using conventional and flouroscopic techniques. Normal gastrointestinal and cardiovascular structures were difficult to resolve on survey radiographs, but were well visualized with gastrointestinal follow through studies and angiography, respectively. All three contrast agents (iohexol, Gastrografin, and barium sulfate) used for the gastrointestinal studies varied minimally in their radiographic quality and transit times, and all appeared to be safe for use in the horseshoe crab. 相似文献
16.
Although Synchytrium endobioticum has been found in almost all potato-growing countries of the EPPO region, it is absent from the great majority of fields. A few plots scattered across the potato-growing areas have been ‘scheduled’ as infested but potatoes are not grown on them. The disease is accordingly hardly ever seen. This is the result of continent-wide multiyear campaign of potato wart control within countries, according to which it is prohibited to grow potatoes on infested plots, and only resistant cultivars may be grown in a safety zone around them. S. endobioticum can persist for several decades in soil, as resting spores, but it is now dying out in plots that have been subject to the control campaign for a sufficiently long period. Procedures are now being agreed for officially ‘descheduling’ such plots. 相似文献
17.
ELIZABETH A. MAULDIN DANNY W. SCOTT WILLIAM H. MILLER & CHRISTINA A. SMITH 《Veterinary dermatology》1997,8(3):191-202
A retrospective histopathological and immunopathological study was conducted on 86 dogs with Malassezia dermatitis. West Highland White terriers, English Setters, Shih Tzus, Basset Hounds, American Cocker Spaniels, spayed females, and castrated males were found to be at increased risk. The histopathological reaction pattern of lymphocytic superficial perivascular to interstitial dermatitis with parakeratotic hyperkeratosis, irregular epidermal hyperplasia, diffuse intercellular oedema and lymphocytic exocytosis was found to be consistent with a diagnosis of Malassezia dermatitis whether yeast were histologically visible (73.3% of the cases) or not (26.7%). Immunopathological studies revealed that 60– > 90% of the inflammatory cells within the epidermis, and 25–75% of those within the dermis were CD3+T lymphocytes, and that the only immunoglobulin-positive cells were dermal plasma cells. 相似文献
18.
JOHN V. YOVICH BSc BVMS A. S. TURNER BVSc MS DiplomateACVS F. W. SMITH BSME MSME PhD 《Veterinary surgery : VS》1985,14(3):230-234
Comparison was made of the holding power of 5.5 and 4.5 mm cortical orthopedic screws inserted into third metacarpal and metatarsal cadaver bones from 3- and 8-year-old horses. The tensile strength of these screws was tested mechanically. In nine comparative trials of these screws, 5.5 mm screws pulled out of bone in five trials at an average of 116.0 kg tensile force and broke in four trials at an average of 1383.2 kg. A 4.5 mm screw pulled out of bone at 834.5 kg in one trial, and screws broke at an average of 849.2 kg in eight trials. The larger 5.5 mm screw required a significantly greater (p = 0.022) pullout force than the mean force at 4.5 mm screw breakage. Fixation failure was due to screw breakage or bone shear, with 5.5 mm screws occasionally creating bone fragmentation during pullout. The average tensile breaking strengths of the 5.5 mm screws (1391.4 kg) and 4.5 mm screws (832.7 kg) determined mechanically were similar to forces at screw breakage during pullout testing in bone. Since the 5.5 mm screws have greater holding power and tensile strength than 4.5 mm screws, the use of the 5.5 mm screw in fracture repair in adult horses is recommended. 相似文献
19.
Medial Plating for the Repair of Middle and Distal Diaphyseal Fractures of the Humerus in Dogs 总被引:1,自引:0,他引:1
JOSEPH HARARI ms dvm SIMON C. ROE bvsc mvst ANN L. JOHNSON dvm ms Dipiomateacvs CHARLES W. SMITH dvm ms Dipiomateacvs 《Veterinary surgery : VS》1986,15(1):45-48
Six middle and distal humeral shaft fractures in dogs were repaired by the application of a bone plate along the medial shaft of the humerus. In all animals, clinical and radiographic evidence of normal bone healing was observed. The bone plate and ancillary implants were removed from five dogs by 10 months. In none of the six dogs were any untoward effects of placing the bone plate along the medial shaft of the humerus detected nor were there any difficulties encountered with the medial humeral soft tissues. 相似文献
20.