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991.
992.
993.
J.O. Grunow P.A. Pieterse D.E. Borlinghaus 《African Journal of Range and Forage Science》2013,30(3):25-29
Abstract A fodder flow/animal experiment 40,8 ha in extent (7,5 ha irrigated), with 19 paddocks, was carried out over a two and a half year period. The aims were: firstly, to compare fodder crops within seasons, and fodder flows over three seasons (winter‐spring‐summer), by means of pasture and animal parameters; secondly, to make economic comparisons between different fodder flows, for growing out beef steers. The conclusions were that: Digitaria eriantha ssp. eriantha is superior to Eragrostis curvula cv. Ermelo for animal production; maize residue gives economically favourable results due to low costs and compensatory growth of cattle; an irrigated pasture providing fodder in more than one season of a flow, for example, Festuca foggage — Festuca pasture — Digitaria pasture, gives a very profitable fodder flow, because the costs of production are divided between two seasons; dryland fodder flows with the sequence maize residue — silage or hay — Digitaria or, with silage or hay replacing the maize residue, were also very profitable; and, the fodder flow giving the highest livemass gain per steer, is not necessarily the most economic. Different kinds and classes of livestock require different fodder flows. 相似文献
994.
陇东黄土高原牧草气候生产潜力评价 总被引:6,自引:4,他引:2
综合考虑光、温、水等影响牧草生长发育的基本要素,采用数学模型,计算了陇东黄土高原牧草气候生产潜力,从而对该区的牧草生产能力进行初步评估和分析,为进一步发展区域草业生产提供相关依据。 相似文献
995.
AIMS: To determine the effectiveness of intra-rumenal controlled release capsules (CRC) containing 32?g of monensin administered pre-calving to reduce the cumulative incidence of subclinical ketosis (SCK) in mainly pasture-fed dairy cows.METHODS: Cows (n=837) due to calve in the first 6 weeks of the spring calving period were enrolled from four commercial herds in the Waikato region of New Zealand in a blinded, randomised, negative-controlled field trial. Three weeks before the start of the calving period cows were randomly allocated to receive either no treatment (control) or a single CRC containing monensin and then blood sampled on two occasions, 7 days apart within 12 days following calving for measurement of concentrations of beta hydroxybutyrate (BHBA) in blood. Cows were diagnosed with SCK if the concentration of BHBA in blood in either of these samples was ≥1.2?mmol/L.RESULTS: Fewer treated cows were diagnosed with SCK within 12 days post-calving than control cows (144/340 (42.4%) vs. 192/336 (57.1%); p<0.001). There was no interaction between treatment group and age, breed or herd of origin. From the final multivariable model it was estimated that treatment with CRC containing monensin reduced the absolute cumulative incidence of SCK by 17.9 (95% CI=9.2–25.8)% compared to no treatment.CONCLUSIONS: Treatment with a CRC containing monensin >10 days prior to calving reduced the cumulative incidence of SCK of pasture-based dairy cows in commercial dairy herds within 12 days post-calving.CLINICAL RELEVANCE: Administration pre-calving of an intra-rumenal bolus containing monensin can be considered as one of a range of management options for the control of SCK in early lactation. 相似文献
996.
黄土丘陵区苜蓿地的土壤呼吸 总被引:1,自引:0,他引:1
土地利用的变化会影响到生态系统碳循环过程。中国退耕还林还草工程实施后,大量农田转变为林地和草地。为了摸清退耕后土壤碳排放的变化,在宁夏黄土丘陵区,对退耕苜蓿(Medicago sativa)地、农田和天然草地的土壤呼吸进行了测定。结果表明,土壤温度和土壤呼吸相关性较强,土壤水分和土壤呼吸没有显著相关性;苜蓿地、农田、天然草地的年均土壤呼吸值分别为1.60、1.03和0.85 μmol·m-2·s-1,苜蓿地土壤呼吸比农田高出55.3%,比天然草地高出88.2%;年CO2排放量分别为1 461.96、940.66和777.36 g·m-2·a-1。农田转化为苜蓿地9年后,土壤CO2排放量增加、有机碳含量下降。在黄土丘陵区退耕还草初级阶段,生态恢复措施对固碳增汇的贡献有限。 相似文献
997.
基于中蒙典型草原不同放牧方式,研究了不同放牧方式下中蒙典型草原土壤理化特性.研究结果显示,蒙古四季游牧样地和内蒙古两季轮牧样地除砂土、pH和全钾含量低于内蒙古四季轮牧和定居样地外,其他性状均高于内蒙古四季轮牧和定居样地.土壤理化特性间相关分析表明,土壤水分与砂土间呈显著负相关(P<0.05),与有机质、C/N、碱解氮、全磷、速效磷和速效钾间呈极显著正相关(P<0.01);土壤其他理化特性间也存在一定相关性.群落多样性指数与土壤特性间相关分析表明,群落多样性指数与砂土、pH及全钾间呈负相关,与其他土壤特性间存在正相关关系. 相似文献
998.
Anaya-Ortega JP Garduño-Castro G Espinoza-Ortega A Rojo-Rubio R Arriaga-Jordán CM 《Tropical animal health and production》2009,41(4):607-616
Small-scale dairy systems based on grazing have dry-season herbage shortages. A repeated 3 × 3 Latin Square experiment evaluated
grazing with silage from maize (MS), annual ryegrass (ARG) or a mixture (MIX) with 9 cows with 3 week periods; continuously
grazed at 3.6 cows/ha with 3.6 kg DM/day of concentrate. Treatments were 7 kg DM of MS, ARG or a 2 MS:1 ARG mixture. Milk
yield (MY), milk composition, live-weight, body condition, silage and concentrate intake were recorded. Herbage DM intake
was estimated indirectly. Activity budgets were done for economic analysis. MY on MS (21.5 kg/cow/d) was 0.06 higher than
on ARG (P < 0.09) with no differences on MIX. There were no differences for milk fat, milk protein, or body condition score.
Live-weight on ARG was higher (P < 0.01) than on MS or MIX. Silage intake was higher (P < 0.01) on ARG and MS than on MIX.
Herbage intake was lower (P < 0.05) on MS, compared with MIX and ARG. Total DM intake on ARG was higher than MS (P < 0.01),
and MIX in between. MS resulted in 0.12 higher economic returns over ARG which had highest costs. Annual ryegrass may have
a place in small-scale systems, but not as silage due to higher costs. 相似文献
999.
Yang J Ferreira R Duponte MW Fukumoto GK Zhao B 《Tropical animal health and production》2009,41(4):593-598
Angus Plus cattle offer advantages for heat tolerance and forage utilization by introduction of Brangus and Brahman to Angus.
To evaluate its adaptability in Hawaii Islands, we reported the growth performances of 213 F1 Angus Plus calve grazing on
pasture. Least-square means of pre-weaning ADG ranged from 1,087 to 1,167 g in bull calves and from 1,030 to 1,048 g in heifer
calves. The 205 d-adjusted weaning weight were 226 to 285 kg in bulls and 214 to 252 kg in heifers. The birth weight and hip
height at birth were significantly correlated with weaning weight, 205 d-adjusted weaning weight, hip height at weaning and
pre-weaning ADG (P < 0.01). Sire group significantly influenced pre-weaning growth performances through interaction with sex of calf. Bull calves
from sire group of high growth were 1.0–3.8 kg heavier in birth weight than the bull calves from other sires (P < 0.001). Sire group x sex interaction was significant (P < 0.05) for calf birth weight, 205-d adjusted weaning weight and pre-weaning ADG. Sire group also played a significant role
in hip height at birth (P < 0.05). Selections of the sires preferable for growth significantly improved calf pre-weaning growth performances. 相似文献
1000.
Fourty-eight Churra Tensina single male lambs were used to evaluate the effect of different feeding systems on carcass composition and predict the carcass tissue composition from joint composition and carcass measurements. Four treatments were studied: GR, unweaned lambs continuously grazing with ewes; GR + S, the same as the previous group, but lambs had free access to concentrate; DRL-GRE, lambs remained indoors with free access to concentrate and ewes grazed for 8 h/day, thereafter remaining with lambs; and DRL, lambs and ewes were kept in confinement, they had free access to concentrate and dry unifeed respectively. In the DRL-GRE and DRL groups lambs were weaned when 45 days old. Lambs were slaughtered at 22–24 kg live weight. Commercial joints from the half left carcass were obtained, recorded and dissected to determine carcass tissue composition.The feeding system had an effect on the proportion of the carcass tissue composition. GR treatment showed higher muscle (M) (p < 0.05) and bone (B) (p < 0.001) percentages, and a lower total fat (F) percentage (p < 0.001) than the rest of treatments. Hence it revealed higher M/F (p < 0.01) and lower M/B (p < 0.05) and subcutaneous fat/intermuscular fat ratios (SF/IF; p < 0.001). Carcass composition predictions were more accurate for grams than for percentages. In predictions from joint composition, pelvic limb was the most accurate joint for grams (R2 = 0.84, R2 = 0.68, and R2 = 0.77 for muscle, bone, and fat, respectively) as well as for percentage (R2 = 0.65, R2 = 0.56, and R2 = 0.73 for muscle, bone, and fat, respectively). Predictions from carcass measurements were greater in muscle and fat grams (R2 = 0.87 and R2 = 0.86 for muscle and fat, respectively) than in percentage (R2 = 0.58 and R2 = 0.73 for muscle and fat, respectively). Equations to predict carcass tissue that include carcass measurements are a simple method to assess accurately saleable muscle yield from different lamb feeding systems without involving carcass damage. 相似文献