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31.
Background: The potential for acid-detergent insoluble ash (ADIA), alkaline-peroxide lignin (APL), and acid-detergent lignin (ADL) to predict fecal output (FO) and dry matter digestibility (DMD) by cattle offered bermudagrass [Cynodon doctylon (L) Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 hay diets: low (L), medium low (ML), medium high (MH), and high (H) crude protein (CP) concentration (79, 111,131, and 164 g CP/kg on a DM basis, respectively). Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08:00 and 16:00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake (DMI), DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD. Results: Forage DMI was affected by diet (P = 0.02), and DMI from MH and H was greater (P 〈 0.05) than from L. Apparent DMD tended (P = 0.08) to differ among diets while FO (P = 0.20) was not affected by diet treatments. Average ADL recovery (1.16) was greater (P 〈 0.05) than that of ADIA (1.03) and APL (1.06), but ADIA and APL did not differ (P = 0.42). Estimates of FO and DMD derived using APL and ADIA were not different (P≥0.05) from total fecal collection while those using ADL differed (P 〈 0.05). There was no diet by marker interaction (P≥ 0.22) for either FO or DMD. Conclusion: Acid-detergent insoluble ash and APL accurately predicted FO and DMD of cattle fed bermudagrass hay of varying nutrient composition. These internal markers may facilitate studies involving large numbers of animals and forages. Results from such studies may be used to develop improve  相似文献   
32.
Postlarvae or juveniles of Macrobrachium rosenbergii produced in Mauritius are sold at unit price to prawn farmers and are counted individually by hand. This process is time consuming, labour intensive, subject to error and may stress the juveniles; safe rapid electronic counting would be highly advantageous.The design of the hydraulic component of a successful counter prototype, Type A, is described. The counter has 10 parallel channels through which juveniles are carried in a water current. The detection of juveniles passing through these channels can be done photo-electrically. The counter accepts juveniles up to 15 mm in length (eye orbit to tip telson) and has the significant advantage that it can be constructed using only simple hand tools.Survival and growth rate tests, and microscopic examination for damage to appendages of juveniles were done on machine counted and hand counted juveniles. There was no reduction of growth or survival caused by passage through the counter by comparison with the hand counting method, and it is concluded that the counter is not detrimental to juvenile prawns.About 70% of all juveniles tested showed highly variable amounts of damage. The great majority of this damage appears to originate in the hatchery tanks, prior to the experimental treatments. Only in the case of antennules could the use of the counter be shown to increase damage significantly, i.e. from 25% to 38%, but this has no detectable effect on subsequent survival or growth.This appears to be the first counter made specifically for counting macroscopic crustacean juveniles, and via suitable scaling, adaptation to counting other species of crustaceans, fish larvae, etc., should be possible.  相似文献   
33.
刘安芳 《畜禽业》2003,(2):38-39
选用1日龄健康樱桃谷肉鸭600只,随机分为3组,每组设4个重复,每个重复50只肉鸭,试验采用单因素完全随机试验设计。A组饲喂基础日粮,B组、C组在基础日粮的基础上分别添加0.2%、0.4%的双乙酸钠。试验结果表明:日粮中添加双乙酸钠对肉鸭日增重、瘦肉率有显著影响(P<0.05);对肉鸭的饲料转化率有极显著影响(P<0.01);对肉鸭的成活率和屠宰率、皮脂率无显著影响(P>0.05)。B组日增重比A组提高了8.65%(P<0.05),比C组提高了5.45%(P>0.05);B组料肉比较A组降低了11.52%(P<0.01),较C组降低了3.29%(P<0.05);B组的成活率与A组、C组间差异不显著(P>0.05);B组每只肉鸭分别比A、C组多盈利1.04元、1.06元。  相似文献   
34.
Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.  相似文献   
35.
The efficacy of clavulanate-potentiated amoxycillin was compared with amoxycillin alone in experimental staphylococcal infection in dogs and in a controlled trial in clinical cases of skin infection in dogs and cats. The experimental infection was produced by subdermal inoculation with beta-lactamase producing (amoxycillin resistant) staphylococci absorbed in cotton dust. This produced discrete, localised lesions with no systemic involvement. In a cross over study, six animals were randomly allocated to treatment with either amoxycillin alone (10 mg/kg, dosed twice daily) or a formulation of clavulanate-potentiated amoxycillin (12.5 mg/kg, of a 1:4 ratio, dosed twice daily). The lesions of the animals treated with clavulanate-potentiated amoxycillin resolved more quickly than those treated with amoxycillin alone. The difference was significant (P less than 0.05) for both lesion diameter and inflammation score after day 6 of treatment. A trial was carried out in clinical cases of skin disease which were randomly allocated to twice daily treatment with either amoxycillin alone (10 or 20 mg/kg), or with clavulanate-potentiated amoxycillin (12.5 or 25 mg/kg of a 1:4 ratio). The required duration of treatment was shorter (P less than 0.5) for the potentiated amoxycillin treatments, and the success rate (judged by cure or substantial improvement) was higher (P less than 0.05) for this group, especially (P less than 0.01) where amoxycillin resistant organisms were isolated. It was concluded that clavulanate-potentiated amoxycillin was an effective treatment of skin infections both under experimental and clinical conditions.  相似文献   
36.
The effect of vitamin A deficiency on the activity of peritoneal macrophages (PM) was investigated in noninfected and Newcastle disease virus (NDV)-infected chickens. Day-old chickens with limited vitamin A reserves were fed diets containing either marginal (120 retinol equivalents (RE)/kg) or adequate (1200 RE/kg) levels of vitamin A. At 4 weeks of age, half of the chickens in each group were infected with the La Sota strain of NDV and PM were isolated 11 or 12 days later. These were used for counting the uptake of fluorescein isothiocyanate-labeled yeast cells as an indicator of phagocytic activity and for measuring the reduction of nitroblue tetrazolium (NBT), which provides an estimate of oxygen-dependent killing of microorganisms. Vitamin A deficiency impaired NBT reduction and, to a lesser extent, phagocytosis in both infected and noninfected chickens. NDV infection increased phagocytosis and NBT reduction in normal and, to a lesser extent, in vitamin A-deficient chickens.  相似文献   
37.
Sixty-eight cases of suppurative, ulcerative endometritis associated with Bovine Herpesvirus-4 (BHV-4) in postparturient dairy cows (62 Holsteins and 6 Jerseys, mean age 4.2 years) were confirmed by a combination of histopathology, fluorescent antibody assays, electron microscopic evaluation of uterus, and polymerase chain reaction (PCR). All cases occurred in the 3- to 28-day postpartum period, and histologic lesions among various cows were consistent when compared with postpartum interval. The endometrial lining epithelium was necrotic and ulcerated from 3 to 7 days postpartum, with only mild inflammation in the lamina propria and submucosa. From 1 to 4 weeks postpartum, the ulcers were confluent to diffuse. Epithelium was replaced by fibrinonecrotic, suppurative mats, resulting in severe bacterial pyometra by day 24. Seroprevalence to BHV-4 in one dairy with a history of 18 mortality cases was 36% (107 of 296). In a random sample of 8 cows from this herd, none had serologic titers in blood sampled 2 weeks prepartum, but 3 of 8 seroconverted with significant titers of 1:8 to 1:16 at 2 weeks postpartum. By 10 weeks postpartum, all 8 cows returned to negative serologic status. Two of 6 cats from the premises also had positive titers. Random serum samples taken from 480 dairy cattle at sale barns indicated 76 (16%) were positive by serum neutralization. Clinical signs, postparturient timing, and histologic lesions were very similar to those previously reported in Belgium with BHV-4. But sequence analysis of PCR products of the glycoprotein B region of 4 separate field isolates of endometriotropic BHV-4 suggests these field isolates were more closely related to the North American nonvirulent strain DN-599 than to the endometriotropic European strain V.  相似文献   
38.
Necropsy records for 102 Attwater's prairie chickens (Tympanuchus cupido attwateri) that had been captive-reared and had died at the San Antonio Zoo over a 4-yr period were evaluated to determine the causes of mortality. Gross necropsy, histopathology, and bacterial culture findings are summarized. Mortality was highest in young birds (<6 mo) and embryos. Husbandry- and gastrointestinal-related diseases were the most common causes of mortality.  相似文献   
39.
It is increasingly important to be able to monitor and maintain the quality of estuaries for overwintering shorebirds. Bird numbers alone are not sufficient to indicate quality nor, as recent research shows, can it be assumed that site quality is being maintained simply because there is enough food to meet the birds’ physiological demands; i.e., the amount of food available per bird in autumn needs to be greater than the amount eaten. But how much greater? We used a simple individuals-based and behaviour-based model to explore the factors that affect the relationship between overwinter mortality and the amount of food available per bird in autumn (the food:bird ratio). The aims were to explore how the natural history characteristics of a shorebird species affected the shape of this relationship, in order to identify characteristics of the system that should be included in any monitoring programme of site quality. In all cases there was a minimum threshold food:bird ratio above which mortality did not vary and below which mortality increased steadily. The amount of food per bird required at the threshold varied from one to six times the amount actually consumed by each bird during winter, depending on the amount of realism included in the model. The minimum threshold ratio was most strongly influenced by the shape of the relationship between intake rate and prey density - the functional response - and, when interference competition occurred, by the distribution of the birds’ main food supply. Simulations with realistic spatial distributions of prey predicted that the minimum required amount of food per bird would be between two and five times the amount actually consumed. The threshold approach could provide a simple method of monitoring estuary quality based on food supply and bird numbers. It also provides a potentially clearly-defined and unambiguous measure of the carrying capacity of a site. If applied to a sufficient number of real estuaries, general guidelines for maintaining estuary quality based on estuary characteristics, food supply and bird species might be established.  相似文献   
40.
Bioavailability of dietary folate might be impaired by the polyglutamate chain to which approximately 70% of dietary folates are bound. This chain must be removed enzymatically in the intestine before folate is absorbed as a monoglutamate. To increase formation of monoglutamate folate in vegetables, the vegetables were subjected to various processing treatments. Treatments included freezing (-18 degrees C, 16 h) and thawing (4 degrees C, 24 h) and hydrostatic high-pressure treatment (200 MPa, 5 min). Both freezing/thawing and high-pressure treatment increased the proportion of folate in the monoglutamate form in leeks, cauliflower, and green beans 2-3-fold. However, loss of total folate after these treatments was >55%. It is concluded that conversion of folate polyglutamate to the monoglutamate form in vegetables is possible by certain processing treatments. Potentially this could lead to vegetables with higher folate bioavailability. However, to prevent folate loss into processing water, processing in a closed system should be applied.  相似文献   
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