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61.
This study was conducted using 120 multiparous Awassi ewes during the breeding season to compare the effects of using previously used controlled internal drug release (CIDR) on the hormone profiles, reproductive performance and economic measures of ewes. Ewes were randomized to receive one of five previously used CIDR (previously used for 6, 12, 18, 24 or 30 days) or the new CIDR as a control for 6 days (CIDR6, CIDR12, CIDR18, CIDR24, CIDR30, and CIDR0 [control], respectively). Blood samples were collected on four occasions, at the time of CIDR insertion, after 3 days of insertion, and at the time of withdrawal and insemination. Serum estradiol (E2) and progesterone (P4) concentrations were measured. Timed insemination was performed 48 hr post‐CIDR withdrawal. Pregnancy was diagnosed by ultrasonography 23 days after insemination and confirmed on day 35. The heat detection rate was significantly (p < 0.05) higher in the CIDR0 and CIDR6 groups than in the CIDR18 and CIDR30 groups. The total pregnancy rate and fecundity were significantly (p < 0.05) higher in the CIDR6 group than in other groups. P4 level was significantly (p < 0.05) higher in the CIDR0 group than in the CIDR30 group at the time of removal. At each time point, the E2 level was significantly (p < 0.05) higher in the CIDR6 group than at the other groups. The total variable cost, total cost, return and net profit were higher in the CIDR6 and CIDR0 groups than in the other groups. In conclusion, although previously used CIDRs are efficient at synchronizing oestrus in ewes, the duration of previously usage significantly affected the reproductive parameters and economic profit. CIDRs previously used for 6 days and new CIDRs provided the highest fertility and fecundity rates, besides return and net profit. Economically, it is not advisable to use CIDRs that previously used for 12 days or more.  相似文献   
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63.
As maize is a chilling-sensitive crop, low temperatures during the early stages of development can be injurious to crop growth and development. Prime mechanism behind chilling-induced damage is oxidative stress. This study was undertaken to improve the chilling tolerance in hybrid maize by seed priming with KCl. For priming, seeds of the maize hybrid Hycorn 8288 were soaked in 50, 100 and 150 mg l−1 aerated solution of KCl for 24 h and then re-dried close to original weight. Primed and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Seed priming improved the performance of maize under both normal and stress conditions. It was found that the chilling tolerance in maize is well associated with the enhanced capacity of the anti-oxidative system. Priming with KCl significantly improved the chilling tolerance mainly by the activation of antioxidants including catalase, superoxide dismutase and ascorbate peroxidase enzymes. KCl treatments also improved the germination rate and time, root and shoot length, and fresh and dry weights of seedlings compared with control. Soluble sugars and α-amylase activity determined as general metabolic indicators of stress were also improved by seed priming with KCl. Other possible bases of chilling tolerance in maize included maintenance of high tissue water contents, reduced electrolyte leakage and carbohydrate metabolism. Seed treatment with 100 mg l−1 KCl was the best treatment to improve the performance of hybrid maize both under normal and chilling stress conditions.  相似文献   
64.
Combining ability and heterosis were studied in a 6 × 6 diallel cross to see the nature of gene action in Upland cotton (Gossypium hirsutum L.) during 2002 to 2004. Analysis of variance revealed highly significant differences among all the F1 and F2 hybrid means and their respective six parental values for all the traits examined. In both generations, the mean squares due to general combining ability (GCA) and specific combining ability (SCA) were also highly significant. SCA genetic variances were greater than GCA and more important for the traits, i.e. boll weight, boll number and seed cotton yield per plant, showing the predominance of non-additive gene action. Lint % in both generations and boll weight in F2s only were controlled by additive type of gene action due to maximum GCA variances. Cultivar CIM-1100 was found to be the best general combiner and its utilization produced valuable hybrids with desirable SCA in both generations. F1 and F2 hybrids, viz., CIM-1100 × CRIS-9, CIM-1100 × FH-682, CIM-1100 × BH-36 and CIM-109 × CIM-1100 as high × low and low × high parents performed well in SCA determination, outstanding mean performance and heterosis. Better SCA effects associated with useful heterosis were more pronounced for yield traits. In F1 hybrids, maximum heterosis was observed for seed cotton yield followed by boll number, boll weight and lint %. The heterosis over better parent was +3.13 to +65.63% for bolls per plant, +0.75 to +24.40% for boll weight, +0.82 to +115.22% for seed cotton yield and +0.27 to +3.88% for lint %. Involvement of CIM-1100 in most of the F1 and F2 hybrids resulted in the synthesis of superior genotypes for most of the traits studied. Inbreeding depression was elevated in good performing hybrids and was the highest for seed cotton yield. Highest yielding F1 hybrids yielded lesser in the subsequent generation due to over-dominance and inbreeding depression, whereas moderate yielding F1 hybrids were found more stable even passing through process of segregation due to additive gene action. The combined performance of F1 and F2 hybrids could be a good indicator to identify the most promising populations to be utilized either as F2 hybrids or as a resource population for further selection.  相似文献   
65.
A survey of insect pests of stored products in three main regions of Saudi Arabia was carried out during two successive years, 1978 und 1979. Randomized samples of different commodities were collected for inspection from 13 localities four times a year. Thirty six species of insect pests belonging to 12 families and 4 orders in addition to 2 hymenopterous parasites were recorded.  相似文献   
66.
In the Forest Department of Bangladesh, a Participatory Agroforestry Program (PAP) was initiated at a denuded Sal forests area to protect the forest resources and to alleviate poverty amongst the local poor population. We explored whether the PAP reduced poverty and what factors might be responsible for poverty alleviation. We used three poverty measurement methods: the Head Count Index, the Poverty Gap Index and the Foster-Greer-Thorbecke index to determine the extent poverty reduction. We used a linear regression model to determine the possible differences among factors in poverty reduction. Data were collected through semi-structured questionnaires and face to face interviews within the study area. PAP proved effective at poverty alleviation, considerably improving the local situation. The linear regression model showed that PAP output explained the income differences in poverty reduction. Participants identified bureaucracy and illegal money demands by forest department officials, an uncontrolled market system, and underdeveloped road infrastructure as the main obstacles to reduction of poverty. Overall, PAP is quite successful in alleviating poverty. So this program might be ofinterest at other degraded forest areas as a tool to alleviate poverty.  相似文献   
67.
Three organic wastes (banana skin (BS), brewery spent grain (BSG), and spent mushroom compost (SMC)) were used for bioremediation of soil spiked with used engine oil to determine the potential of these organic wastes in enhancing biodegradation of used oil in soil. The rates of biodegradation of the oil were studied for a period of 84 days under laboratory conditions. Hydrocarbon-utilizing bacterial counts were high in all the organic waste-amended soil ranging between 10.2?×?106 and 80.5?×?106?CFU/g compared to unamended control soil throughout the 84 days of study. Oil-contaminated soil amended with BSG showed the highest reduction in total petroleum hydrocarbon with net loss of 26.76% in 84 days compared to other treatments. First-order kinetic model revealed that BSG was the best of the three organic wastes used with biodegradation rate constant of 0.3163 day?1 and half-life of 2.19 days. The results obtained demonstrated the potential of organic wastes for oil bioremediation in the order BSG?>?BS?>?SMC.  相似文献   
68.
In this study growth and yield response of wheat crop to phosphobacterium inoculum was observed under sandy loam conditions. The investigations were carried out at field experiment. The experiment was laid out in Randomized Complete Block Design. The treatments were; 120-0-0 NPK kg/ha−1 (T 1), 120-50-0 kg/ha−1 (T 2), 120-100-0 NPK kg/ha−1 (T 3), T 1 + Phosphobacterium inoculum (T 4), T 2 + Phosphobacterium inoculum (T 5) and T 3 + Phosphobacterium inoculum (T 6).The results showed that bacterial strain (Pseudomonas spp.) was able to effect on yield and its attributes in wheat crop. The crop showed significant positive results. The inoculation significantly stimulates the germination count (m−2), number of tillers and spikes (m−2), 1000 grains weight (g) and grain yield (kg/ha−1). We suggest that application of 120-100-0 kg/ha−1 NPK along with coating of seed with phosphobacterium (Pseudomonas spp.) all the way through inoculation is a better practice to reduce the exploit of phosphatic fertilizers which are much costly.  相似文献   
69.
利用微量元素来最大限度地促进生产   总被引:1,自引:0,他引:1  
AzizSacranie 《中国家禽》2005,27(22):47-50
在过去的15年中,肉鸡养殖业中的遗传改良是显著的.一个领先的种鸡公司声称仅在这一时期其产品的饲料转化率就提高了35个百分点,活重肉产量提高了4.5%.实际生产中这些遗传改良有可能还在继续.这些改善是合乎人们需要的,因此,通过营养和管理手段,特别是在亲本饲养方面,来充分发挥这种遗传潜力,就非常有挑战性.  相似文献   
70.
Aqueous solutions (0, 0.01, 0.1, 1 mM) of PAs (putrescine, spermine, spermidine) containing a surfactant ‘Tween 20’ were sprayed onto panicles of mango (Mangifera indica L. cv. Kensington Pride) at final fruit set (FFS) stage (when all flowers abscised but remain attached to the panicle) during 1999–2001 to investigate their effects on fruit retention, yield, size, and fruit quality. The optimum time of PA application for improving final fruit retention and fruit yield was determined by spraying different concentrations (0, 0.01, 0.1, 1 mM) of spermine (SPM) containing a surfactant ‘Tween 20’ at four phenological stages including flower bud differentiation (FBD), 5–8 cm long grown panicles (GP), full bloom (FB) and at initial fruit set (IFS) stage (when 2/3rd of the flowers were abscised but attached to the panicle) during 2000. Exogenous application of PAs at FFS stage did not significantly increase fruit retention. However, compared to control (0.79 and 2.3% fruit retention), PAs treatments resulted in comparatively higher mean fruit retention (1.53 and 2.92%) during 1999–2000 and 2000–2001, respectively. Among three PAs tested, SPM was more effective in increasing mean final fruit retention. Fruit size was not significantly affected by any PA treatment. Among the four application times, SPM (0.01 mM) spray at FB stage resulted in significantly (P ≤ 0.05) greater fruit retention (4.99%) compared with control (2.1%). However, fruit yield was comparatively higher with SPM (0.01 mM) application at IFS stage or 5–8 cm GP stage compared to the control. Overall FB application was found as the optimum time of application. Application of PAs at FFS stage retarded fruit skin colour development compared to the control. Sugars and total soluble solids (TSS) were generally reduced in PA-treated fruit. Fruit acidity was increased (16.7%) with SPM, whereas it was 11% with PUT treatment as compared to the control. Total carotenoids in pulp were generally improved (49%) with PA treatments, compared to the control. Ascorbic acid concentrations were significantly reduced with spermidine (SPD) (24%) and PUT (20%) treatments, whereas higher concentrations of SPM (1 mM) tended to increase it (12.7%) compared to the control. In conclusion, application of SPM (0.01 mM) at FB stage resulted in the highest fruit retention, whereas SPM (0.01) spray at GP or IFS stage resulted in higher fruit yield. PUT application at FFS stage significantly improved fruit quality by increasing total carotenoid, while reducing acid content of ripe fruit.  相似文献   
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