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31.
Small plots of a Festuca-Agrostis upland sward on a peaty gley podsol were strip-seeded during late June 1986 with white clover cvs Aberystwyth S184 or Menna at 4 kg ha−1 and defoliated early (20 August) or late (3 September) and then frequently or infrequently (every 2 weeks or 4 weeks) until the end of September. All plots were defoliated in early November, at 3-weekly intervals during the growing season in 1987 and then grazed rotationally during 1988.
Satisfactory seedling establishment, representing 46% emergence, was achieved 5 weeks after sowing. The differential defoliation regimes had no persistent significant effects on clover development. S184 soon produced more leaves per seedling than Menna and a smaller proportion of its leaf number and weight were removed at each defoliation. Following large losses of leaves over the 1986–87 winter, SI84 had significantly more leaves per stolon than Menna; subsequently it also colonized the sward at a quicker rate. During 1987 amounts of herbage harvested (6.1 t ha−1 ) were similar with the two clover cultivars, with S184 contributing 47% and Menna 44% of this respectively. SI84 made a larger contribution to yield during May and June but Menna was more productive during September and October. During 1988 clover populations were maintained with rotational grazing without additional fertilizer inputs.
The results show that, despite initial soil and climatic contraints, both small and medium-leaved clovers can be strip-seeded into upland swards with large subsequent benefits to yield and herbage quality. However, they also indicate the need for further experiments to determine the influence of sward morphology and defoliation regime on stolon branching rates and accumulation of growing points which, in turn, govern sward colonization. 相似文献
Satisfactory seedling establishment, representing 46% emergence, was achieved 5 weeks after sowing. The differential defoliation regimes had no persistent significant effects on clover development. S184 soon produced more leaves per seedling than Menna and a smaller proportion of its leaf number and weight were removed at each defoliation. Following large losses of leaves over the 1986–87 winter, SI84 had significantly more leaves per stolon than Menna; subsequently it also colonized the sward at a quicker rate. During 1987 amounts of herbage harvested (6.1 t ha
The results show that, despite initial soil and climatic contraints, both small and medium-leaved clovers can be strip-seeded into upland swards with large subsequent benefits to yield and herbage quality. However, they also indicate the need for further experiments to determine the influence of sward morphology and defoliation regime on stolon branching rates and accumulation of growing points which, in turn, govern sward colonization. 相似文献
32.
White clover (cv. Grasslands Huia) was slot-seeded in April 1982 into plots of permanent pasture of differing botanical composition and reserves of soil phosphate. In one investigation the short-term effects of placing different amounts of phosphate (P2O5) in different positions in relation to the slot were investigated. In another, emphasis was given to effects of a grass-suppressing herbicide, propyzamide, on herbage growth and clover contributon during the second year. Fewer seedlings established on plots with a high initial P status and abundant in Holcus lanatus and Alopecurus pratensis than on plots deficient in P2O5 and dominated by Agrostis capillaris and Festuca rubra. P2O5decreased numbers of establishing clover seedlings when applied in the slots but not when placed beneath them. Growth was increased most when placement was beneath the slot. Application of P2O5to plots previously supplied with it resulted in 7.2 g total above ground and 1.7 g stolon dry weight (m row)?1compared to 1.3 and 0.1 g respectively in plots with low reserves and DO applied P2O5. Propyzamide greatly increased the yield and the contribution of clover in the presence of high initial P status and applied P2O5. Without propyzamide, clover made only a small contribution until July, averaging 7% for the whole season with little benefit from residual P. Clover growth in late summer was increased from 41 to 292 kg DM ha?1 where P2O5 was applied to P-deficient plots sprayed with propyzamide in the previous autumn. The large increases in clover contribution following propyzamide application were accompanied by small decreases in total seasonal yield of grass. The proportions of H. lanatus and. F. rubra. were decreased and of A. capillaris, increased. Spread of clover from the slots was slow during the first year but was encouraged by both P2O5 and propyzamide during the second year. Factors requiring further investigation are discussed. 相似文献
33.
J. F. McCONNELL A. HAYES S. R. PLATT K. C. SMITH 《Veterinary radiology & ultrasound》2006,47(1):72-77
Two bullmastiffs with calvarial hyperostosis syndrome are described and are the first documented examples in females. The clinical and radiologic features were similar to those previously reported in males. Magnetic resonance (MR) imaging findings have not previously been reported. One dog underwent MR imaging and abnormalities included thickening of the frontal bones with loss of normal fat signal and changes in the overlying soft tissues. In one of the dogs, long bone changes were seen in the femora and resembled those seen with craniomandibular osteopathy. 相似文献
34.
P. HAYES 《Grass and Forage Science》1976,31(2):59-64
Investigations were conducted into the seed reserves, shoot and seminal root growth of Lolium perenne, Festuca arundinacea, Holcus lanatus and Poa trivialis. Data are presented for the caryopsis, palea and lemma weights of these species. Shoot lengths of Lolium and Festuca were very similar but seminal root lengths of Lolium were longer and emerged earlier than those of Festuca. The caryopsis in Lolium lost weight much more rapidly in germination than Festuca. Seedlings of Lolium and Festuca showed similar increases in shoot length but Lolium had more rapid rates of seminal root growth and weight loss from the caryopsis. It is suggested that poor field establishment of Festuca may be due to poor mobilization of seed reserves and consequential poor seminal root growth. The possibility of selecting for good seminal root development in Festuca to improve establishment is suggested. 相似文献
35.
For germination ascospores of Crumenula sororia require freemoisture. A temperature range of 2025 °C was optimal.In these conditions rate of germination was increased by extractsof lodgepole pine bark and extracts of Corsican pine bark andwood. Irrespective of whether spores or hyphae were used, C. sororiaonly Successfully invaded Corsican pine through wounds madewith a scalpel or by removing needle fascicles. Lesions didnot develop when frozen tissues were inoculated. In field inoculation experiments different isolates of the fungusdiffered significantly in pathogenicity. Infections developedmore severely on 4-year-old than on 1-year-old branches, andthis agrees with the incidence of natural branch-infections. 相似文献
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38.
Ectopic ureter has been diagnosed in 228 dogs collectively at 15 North American university veterinary medical teaching hospitals over a 17 year reporting period. The female-to-male ratio was 217:11. Among female dogs, six breeds (Siberian husky, Newfoundland, bulldog. West Highland white terrier, fox terrier, and miniature and toy poodle), representing more than half of the total cases, were identified with significantly greater frequency of diagnosis than expected by their representation in the overall hospital population. The strength of association in certain purebred dogs, plus the significant deficit in mongrel dogs supports the likelihood that familial genetics are responsible for a substantial amount of the occurrence of this defect. 相似文献
39.
HOWARD M. HAYES JR 《The Journal of small animal practice》1975,16(1-12):337-343
Of 250, 000 dogs seen by twelve United States and Canadian veterinary-college hospital/clinics, seventy-three dogs were identified with chemo-dectomas. The Boxer and Boston Terrier breeds had significantly higher risk for the tumour than all breeds combined; excessive risk was detected in all male dogs combined and in male dogs 10 years of age and older- especially in Boston Terriers. A familial predisposition aggravated by chronic hypoxia are suggested as possible aetiological factors responsible for the excessive risk in bulldog breeds. 相似文献
40.