全文获取类型
收费全文 | 604篇 |
免费 | 14篇 |
专业分类
林业 | 26篇 |
农学 | 47篇 |
基础科学 | 4篇 |
67篇 | |
综合类 | 14篇 |
农作物 | 25篇 |
水产渔业 | 9篇 |
畜牧兽医 | 399篇 |
园艺 | 8篇 |
植物保护 | 19篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 79篇 |
2012年 | 18篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1976年 | 7篇 |
1968年 | 14篇 |
1966年 | 6篇 |
1964年 | 7篇 |
1963年 | 7篇 |
1960年 | 26篇 |
1959年 | 10篇 |
1957年 | 21篇 |
1956年 | 12篇 |
1955年 | 26篇 |
1954年 | 23篇 |
1944年 | 10篇 |
1943年 | 5篇 |
1942年 | 6篇 |
1941年 | 19篇 |
1940年 | 6篇 |
1927年 | 5篇 |
排序方式: 共有618条查询结果,搜索用时 359 毫秒
611.
Rajat Garg C. L. Yadav R. R. Kumar P. S. Banerjee Stuti Vatsya Rajesh Godara 《Tropical animal health and production》2009,41(8):1695-1700
Epidemiological studies were conducted on Fasciola giagntica infection in different geo-climatic zones (hills, tarai and plains) in six states of north India during January 2001 to December
2004. Prevalence rates of 10.79, 13.90, 2.78 and 2.35 percent were recorded in cattle, buffaloes, sheep and goats, respectively.
Animals in the tarai had the highest prevalence of fasciolosis followed by those in the hills and plains, respectively. The
prevalence of infection in cattle and buffaloes was highest during the winters (11.84% cattle, 15.57% buffaloes) followed
by summers and rains, respectively. However, the seasonal trends in sheep and goats were the reverse, with the peak prevalence
during the rains (4.60% sheep, 2.71% goats). Abattoir studies revealed a higher prevalence in buffaloes (31.14%) than in sheep
and goats. Screening of Lymnaea auricularia snails revealed that 5.48% of the snails harboured larval stages of F. gigantica. Also, the snails in the tarai had a higher prevalence (7.28%) of infection compared to those in the plains (1.57%). The
results of the present study may help to devise an effective control strategy against fasciolosis in north India. 相似文献
612.
Purified corn fiber gum (CFG‐F) isolated from fine (kernel endosperm‐derived) corn fiber that contained ≈2% residual protein was extracted with 70% aqueous ethanol. The aqueous ethanol extract (AEE), which contained 19.5% of the total CFG, contained a high percentage of the proteinaceous material present in the original gum sample. The AEE gum contained 6.81% protein by weight. The residue (R), which constituted 66% of the total CFG‐F, contained only 0.55% of protein. The emulsifying properties of R and AEE in a model oil‐in‐water emulsification system were studied by measuring turbidity after 1, 2, and 3 weeks, particle size after 4 weeks, and by confocal laser scanning microscopy after three months of storage at room temperature. These gums were compared with the standard well‐known emulsifiers native acacia gum (NAG) and modified acacia gum (MAG). The results indicate that although AEE contains protein‐rich components, it is not as good an emulsifier as the residue which contains only 0.55% of protein. However, emulsions prepared with the whole (unfractionated) CFG‐F under similar conditions were more stable showing higher turbidity and smaller particles size than those prepared with either R or AEE. 相似文献
613.
S C Yadav R L Sharma A Kalicharan U R Mehra R S Dass A K Verma 《Veterinary parasitology》1999,82(4):285-296
The clinical course of the primary experimental Fasciola gigantica infection was investigated in riverine buffalo calves of the Murrah breed. Nine male calves aged 12-15 months were randomly assigned to two groups of five (Group I) and four (Group II) animals. Each animal in Group I, was orally infected with 1000 metacercariae (mc) of F. gigantica, whereas Group II animals did not receive any infection dose and served as uninfected controls. No clinical signs of fasciolosis were observed until the sixth week post-infection (PI). Group I animals, however, developed recognised symptoms of acute fasciolosis, comprising apyrexic inappetance, anemia, poor weight gain, diarrhoea and sub-mandibular and facial oedema, respectively, from 5, 6, 8, 16 and 17 weeks PI. The signs were intermittent in nature and of variable duration. The prepatent period was of 92-97 days (mean 95.2 +/- 3.1). One of the five infected animals died on Day 147 PI. At necropsy, 36.8 +/- 11.0% of the infection dose was recovered as adult fluke population. The gross lesions were primarily biliary in nature. Group II, the uninfected controls, throughout the study period of 165 days PI, did not show any symptom and were negative for F. gigantica. The study demonstrated that the onset of adverse effects of F. gigantica on the growth and health of the infected host was mainly noted during late prepatency much before coprological prediction and diagnosis. The significance of preventive therapy against fasciolosis during prepatency has been stressed in endemic areas. 相似文献
614.
OBJECTIVE: To determine the infectivity of ovine and caprine strains of Dichelobacter nodosus for both sheep and goats. DESIGN: Pen experiments in which 20 sheep and 19 goats were challenged directly with the two strains, and transmission experiments on pasture, using donors infected by experimental challenge. RESULTS: Sheep and goat strains of D nodosus infected both animal species in experimental challenges. Animals so infected transmitted footrot to both sheep and goats on pasture plots. A significantly smaller proportion of goats than sheep was infected when challenged with either strain. The interval between exposure and development of footrot in goats was longer than in sheep when recipient animals were exposed to infected donors on pasture. The disease was less invasive in goats than in sheep. CONCLUSIONS: With the strains of D nodosus used there was no evidence of host specificity. Direct transmission of footrot can occur between sheep and goats in the same environment. There is a need to include goats in ovine footrot eradication programs and vice versa. 相似文献
615.
Yadav Shashi Kala Sehgal Salil 《Plant foods for human nutrition (Dordrecht, Netherlands)》1999,53(3):255-263
Bathua (Chenopodium album) and fenugreek (Trigonella foenum graecum) stored in polyethylene bags and without packaging for 24 or 48 hours in a refrigerator at 5 or 30 °C in polyethylene bags. The fresh leaves were also dried (oven and sun); blanched (5, 10 or 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analyzed for total and extractable calcium and zinc content. The Ca and Zn content of these leaves varied from 970 to 2230 and 10.50 to 12.30 mg/100 g DM and the percentage HCl-extractability was 80.34 to 83.04 and 82.43 to 83.90, respectively. Non significant effects of drying and storage were observed on total Ca and Zn content and HCl-extractability while blanching and cooking resulted in significant improvement of HCl-extractability of these two minerals. Thus, cooking and blanching are good ways to improve the HCl-extractability of Ca and Zn. 相似文献
616.
Effects of Weed Removal in Clusterbean (Cyamopsis tetragonoloba) under Different Rainfall Situations in an Arid Region 总被引:2,自引:0,他引:2
R. S. Yadav 《Journal of Agronomy and Crop Science》1998,181(4):209-214
In dry land agriculture, intensity and type of weed pressure depend upon the rainfall pattern during the crop season. A two year field study was conducted to determine the effect of time of weed removal in clusterbean ( Cyamopsis tetragonoloba (L.) Taub.). Treatments consisting of weed removal at 10, 20, 30,40 and 50 days after sowing were compared with clean weeded and unweeded controls. The xerophytic weeds Gisekia pharnacioides (L.) M., Mollugo cerviana (L.) Ser. and Tribulus terrestris L. dominated in the low and erratic 1993 rainfall season while grassy weeds such as Eragrostis pilosa (Beauv) were predominant in the 1994 season with well-distributed rainfall. The number of weeds was maximum at 30 days after sowing (DAS) in 1993 and at 40 DAS in 1994. The dry weight of weeds increased up to 50 DAS in 1993 and up to harvest in 1994. Removing weeds at 20 or 30 DAS increased the number of pods per plant, water use efficiency and seed yield of clusterbean. Water consumption was higher in unweeded plots. Water use efficiency decreased with the increase in time of weed removal beyond 20 days after crop sowing. 相似文献
617.
The phase velocities of Rayleigh waves increase more rapidly with distance from the East Pacific Rise (EPR) axis than is predicted by models of conductive cooling of the lithosphere. Low velocities near the axis are probably caused by partial melt at depths of 20 to 70 kilometers in a zone several hundred kilometers wide. The lowest velocities are offset to the west of the EPR. Wave propagation is anisotropic; the fast direction is approximately perpendicular to the ridge, parallel to the spreading direction. Anisotropy increases from a minimum near the axis to 3 percent or more on the flanks. 相似文献
618.
Ryan C. Hamberg Ramawatar Yadav Philip M Dixon Mark A. Licht Micheal DK Owen 《Pest management science》2023,79(12):4819-4827