全文获取类型
收费全文 | 150篇 |
免费 | 0篇 |
专业分类
林业 | 12篇 |
农学 | 1篇 |
24篇 | |
综合类 | 19篇 |
农作物 | 2篇 |
水产渔业 | 3篇 |
畜牧兽医 | 84篇 |
植物保护 | 5篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 11篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 0 毫秒
71.
Diagnostic ultrasonography of equine limbs 总被引:2,自引:0,他引:2
R L Genovese N W Rantanen M L Hauser B S Simpson 《Veterinary Clinics of North America: Equine Practice》1986,2(1):145-226
In our 3 years of clinical experience, we have found that diagnostic ultrasound provides the veterinarian with a valuable diagnostic tool. It allows the clinician to quantify morphologic change that has occurred as a result of soft-tissue injuries, even when the clinical findings are ambiguous or insufficient. In cases in which aggressive postinjury therapy has been instituted prior to presentation, diagnostic ultrasound is often the only noninvasive method that can ascertain the extent of the horse's injury. Diagnostic ultrasound provides the technology to detect injuries before they become permanently debilitating, because lesions as small as 1 mm in diameter can be detected. Prior to diagnostic ultrasound, the severity of many injuries was underestimated. In such cases, if the horse responded favorably to symptomatic therapy, the client would resume training. The result was often debilitation. Diagnostic ultrasound also enables the clinician to demonstrate visually to the client the location, size, and extent of lesions in the limb. One of the more gratifying effects of a sonographic study is the client's acceptance of the presence and extent of the injury after visualizing it. We have found that the old adage "a picture is worth a thousand words" is generally the rule in obtaining the proper course of therapy for the horse. The ability to make hard copies of sonograms enables the clinician to morphologically evaluate the rate of healing. He can accurately determine the effectiveness of a therapeutic regimen and ascertain when optimal healing has occurred. Diagnostic ultrasound can provide the researcher with an invaluable tool to document and quantify soft-tissue disease. We anticipate that, in the future, the sonographic appearance of recovered tissues will be correlated with new data on the healing process and the effectiveness of various therapies. The material presented above has covered the value of diagnostic ultrasound in major clinical situations related to equine lameness. Other applications, the discussion of which is beyond the scope of this article, include evaluation of the pastern for injuries to the SDF, DDF, and oblique sesamoidean ligament, and evaluation of the navicular bursae. Examination of muscles for hematomas, abscessations, and tears has also been accomplished ultrasonographically. Diagnostic ultrasound has facilitated study of the trochanteric and bicipital bursae, blood flow through arteries, and structures above the carpus and hock. Obviously, the clinical potential of diagnostic ultrasound is limitless.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
72.
Paula D. Modransky DVM Norman W. Rantanen DVM MS Michael L. Hauser BS Barrie D. Grant DVM MS 《Journal of Equine Veterinary Science》1983,3(2):56-58
Diagnostic ultrasonography was used to demonstrate villonodular synovitis of the equine metacarpophalangeal joint. The presence of the soft tissue, intracapsular mass was confirmed with conventional radiography and positive contrast arthrography. The mass was surgically excised and submitted for histopathologic identification. 相似文献
73.
P K Saini G M Peavy D E Hauser S K Saini 《American journal of veterinary research》1978,39(9):1514-1518
Sera of several canine patients contained an isoenzyme of alkaline phosphatase (ALP) that resembled intestinal ALP with respect to heat inactivation, L-phenylalanine inhibition, and sensitivity to anti-canine intestinal ALP antibody, but differed with regard to the electrophoretic migration. The electrophoretic mobility of the isoenzyme was slightly cathodal than that of hepatic ALP, and its migration was reduced, similar to that of hepatic isoenzyme after neuraminidase treatment. This isoenzyme, which could be corticosteroid induced, was in the sera of numerous dogs with hepatobiliary disorders and was different from the hepatic isoenzyme that appeared in the sera of dogs with acute hepatitis, based on anti-canine intestinal ALP antibody interaction, heat inactivation, and electrophoretic migration. 相似文献
74.
75.
Black leaf streak disease (BLSD) affects both bananas and plantains. Anecdotal evidence suggests that when plantain is grown under shade in agroforestry systems, there is less damage from BLSD. In this study, BLSD severity and agronomic fruit characteristics of plantain were compared under high and low timber stand densities (TSD), and also under different crop management systems (mulching, burning, intercropping). By 11 months after planting, in high TSDs, plants had 1.2 more standing leaves, 1.5 more symptom-free leaves and a lower percentage of total leaf area attacked than in low TSDs. At harvest, plants in high TSDs had, on average, 1.4 more standing leaves than those in low TSDs. Percentage leaf area attacked by BLSD was 43.0 % in high TSD treatments, significantly lower than the 57.2 % in low TSD treatments. There was a significant and positive relationship between the number of leaves at flowering and dry fruit bunch mass for plantains grown under low TSD. However, there was no correlation between the number of leaves and fruit mass for the high TSD. The beneficial effects of shade in the high TSD, such as reduced severity of BLSD, were established. However, as there was bunch mass loss associated with reduced leaf production rates under the high TSD, a reduction in BLSD only partially compensated for this yield loss. Thus overall, at the high TSD, there was no yield gain from reduced BLSD. 相似文献
76.
77.
It is well known that wild carrots may pollute the seed cropsof cultivated carrots, but whether cultivated carrots can alsodisperse pollen and seed, and thereby introduce genes into wildcarrot populations, is only little described. In Denmark, there is nocommercial seed production of carrots, and as biennials they shouldnormally not flower before harvest of the roots. Still, floweringindividuals can be found in most Danish fields, and sometimes in veryhigh numbers. At least 75% of the flowering plants are malefertile, with ca. 83% of the pollen being viable. More thanhalf of the plants produce seeds. Pollen and seed dispersal fromfields into wild carrot populations is probably rather frequent inDenmark. A closer inspection of the morphology of flowering plantsindicate that some of these (2–60%) arebolters of pure cultivar origin, as indicated primarily by orangeroot colour. The remainder is probably first or advanced generationhybrids between wild and cultivated plants, as indicated by theirwhite roots and combinations of morphological characters from eitherplant type. Some of these hybrids are imported to Denmark togetherwith the sowing seed, as indicated by significantly differentfrequencies of bolters with white roots in different carrot cultivarstested in the field. 相似文献
78.
Development and comparison of four real-time polymerase chain reaction systems for specific detection and quantification of Zea mays L 总被引:5,自引:0,他引:5
Hernández M Duplan MN Berthier G Vaïtilingom M Hauser W Freyer R Pla M Bertheau Y 《Journal of agricultural and food chemistry》2004,52(15):4632-4637
Four real-time polymerase chain reaction systems aiming at the specific detection and quantification of maize DNA are described. They have been developed in four independent laboratories targeting different maize sequences, i.e., alcohol dehydrogenase (Adh1), high mobility group protein (hmga), invertase A (ivr1), and zein, respectively. They were all fully specific, showing a very similar quantification accuracy along a number of distantly related maize cultivars and being either single or low copy number genes. They were highly sensitive and exhibited limits of quantification below 100 maize genomic copies. In consequence, they are considered suitable for use as maize specific endogenous reference genes in DNA analyses, including GMO quantitative tests. 相似文献
79.
Improvement of the physical fertility of a degraded Alfisol with planted and natural fallows under humid tropical conditions 总被引:2,自引:0,他引:2
Abstract. Topsoil (0–15 cm) bulk density, aggregate stability, soil dispersibility, water retention and infiltration were measured between 1989 and 1996 on an Alfisol under rehabilitation in southwestern Nigeria. The planted leguminous species were Pueraria phaseoloides, Senna siamea, Leucaena leucocephala, Acacia leptocarpa and A. auriculiformis. Also, plots with natural fallow and maize/cassava intercropping were included. Level (minimum) and mound tillage with hoes was adopted for the cultivated areas under study after 4 and 6 year fallow periods. Under fallow, the soil bulk density decreased from1.56 to 1.11 t m73.The continuously cropped treatment (level tillage) had significantly higher bulk density than the fallowed subplots after 6 years. Mean soil penetrometer resistance ranged from 75 to 157 kPa for fallowed plots and from 192 to 295 kPa for the continuously cropped (level tillage) subplot. Surface soilwater contentswere similar for all the treatments during the soil strength measurements. Although soil aggregates were generally of low stability and not well formed, they were improved by fallowing.
Soil structural improvement by planted fallows was similar to that by natural fallow, but the trees were more promising for long-term fallow (>6 years) than the herbaceous P. phaseoloides. However, the improvement in soil structure after 4 or 6 year fallow could not be maintained in subsequent cropping. Furthermore, the significant improvement in soil bulk density caused by A. auriculiformis and natural fallow was more rapidly lost on the cultivated subplots compared with other fallow treatments. Thus, soil structure recovery under a fallow does not imply a sustained improvement when stress is applied to this soil. Post-fallow soil management options such as residue incorporation and tillage to ameliorate compaction or soil strength will be necessary to enhance the improvements by fallow species. 相似文献
Soil structural improvement by planted fallows was similar to that by natural fallow, but the trees were more promising for long-term fallow (>6 years) than the herbaceous P. phaseoloides. However, the improvement in soil structure after 4 or 6 year fallow could not be maintained in subsequent cropping. Furthermore, the significant improvement in soil bulk density caused by A. auriculiformis and natural fallow was more rapidly lost on the cultivated subplots compared with other fallow treatments. Thus, soil structure recovery under a fallow does not imply a sustained improvement when stress is applied to this soil. Post-fallow soil management options such as residue incorporation and tillage to ameliorate compaction or soil strength will be necessary to enhance the improvements by fallow species. 相似文献
80.
A shortleaf pine (Pinus echinata Mill.) ripping study was established by the Missouri Department of Conservation in March 1988 at the Logan Creek Conservation
Area, USA. The objective of the study was to evaluate the effects of ripping on soil chemical and physical properties, on
free-to-grow status, and on survival and growth of planted shortleaf pine seedlings. After 16 years, ripping increased exchangeable
calcium; however, it had no long-term effects on soil particle size, organic carbon, pH, exchangeable potassium and exchangeable
magnesium. Ripping increased the percentage of free-to-grow saplings by 3.8% after two growing seasons. Ripping improved survival
by 4% during the 1st three growing seasons and by 7.1% at age 16. After two growing seasons, ripping improved crown spread
by 13.6%, height by 14.2%, diameter by 14%, and volume by 41.2%. At age 16, ripping no longer had an effect on shortleaf pine
height and had reduced diameter by 5.3% and volume by 11.0%. Our results suggest that ripping 1) had no effect on long-term
physical properties or chemical properties of the soil, 2) had no effect on the number of free-to-grow seedlings, and 3) produced
short-term benefits on survival and growth of planted shortleaf pine. 相似文献