全文获取类型
收费全文 | 884篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
林业 | 62篇 |
农学 | 55篇 |
基础科学 | 8篇 |
229篇 | |
综合类 | 42篇 |
农作物 | 174篇 |
水产渔业 | 110篇 |
畜牧兽医 | 169篇 |
园艺 | 20篇 |
植物保护 | 56篇 |
出版年
2023年 | 2篇 |
2022年 | 25篇 |
2021年 | 39篇 |
2020年 | 34篇 |
2019年 | 46篇 |
2018年 | 53篇 |
2017年 | 63篇 |
2016年 | 69篇 |
2015年 | 38篇 |
2014年 | 55篇 |
2013年 | 100篇 |
2012年 | 69篇 |
2011年 | 77篇 |
2010年 | 46篇 |
2009年 | 35篇 |
2008年 | 68篇 |
2007年 | 24篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有925条查询结果,搜索用时 31 毫秒
51.
F.S. Hamid Tahira Ahmad 《农业科学与技术》2006,7(1):14-22
Field experiment was conducted on mature tea bushes of Qi-Men variety at two different altitudes from sea level i.e. at National Tea Research Institute Shinkiari (1000 m) and on farmer's field in Konsh valley at village Battal (1500 m). Different levels of nitrogen with constant dose of phosphorus and potassium were applied to observe the optimal dose of nutrients for highest yield under local edaphic conditions. The experiment was repeated for three consecutive years. The highest yield of fresh tea leaves were obtained by the application of 420 kg ha^-1 N followed by the application of 360 kg ha^-1 N at 1000 masl. The highest dose of nitrogen also reduced significantly the soil pH in the upper (0-15cm) layer depth during 1998 and 1999. During the year 2000, the reduction in soil pH was observed by the application of highest dose of nitrogen but was non-significant at 5% level. The lower soil depth (15-30 cm) showed the reduction in pH with the highest dose of nitrogen during the experimental year but was statistically non significant.
At the higher altitude of 1500 masl the highest yield of fresh tea leaves was obtained by the application of 420 kg ha^-1 during the experimental years but the increase was significant during the year 1999 and 2000. The yield of the fresh tea leaves was positively correlated with the amount of nitrogen application at both the altitudes. The increasing amount of nitrogen decreased the soil pH at both the depths of 0-15cm and 15-30cm. Unlike the lower altitude (1000 m) there was no any significant reduction in the soil pH during 1998 and 1999. A significant reduction in soil pH was found in the year 2000. 相似文献
52.
53.
The distribution and seasonal variations of petroleum residues in the Shatt al-Arab water column have been determined spectrofluorometrically. Their concentrations were found to vary between 1.7 to 35.4 μg L?1 Kuwait crude oil equivalents. The results suggested that petroleum hydrocarbons present in this river originated from diverse sources. Hydrocarbon amounts tend to be highest in winter (averaged 17.4 μg L?1) and lowest in summer (averaged 3.1 μg L?1). 相似文献
54.
Mohammad Saeed Vaghar Saeed Sayfzadeh Hamid Reza Zakerin Soheil Kobraee Sayed Alireza Valadabadi 《Journal of plant nutrition》2020,43(18):2740-2756
Abstract To investigate the effect of foliar application of nano-chelates of iron, zinc, and manganese subjected to different irrigation conditions on physiological traits, and yield of soybean (cultivar M9), a split plot experiment was conducted in a completely randomized block design with three replications in two crop years (2016–2017). The main plot included four levels of irrigation (I): full irrigation (I 1), irrigation withhold at flowering stage (I 2), irrigation withhold at podding stage (I 3), and irrigation withhold during the grain filling period (I 4). Also, the subplot included eight levels of foliar application with Fe, Zn, Mn, Fe?+?Zn, Fe?+?Mn, Zn?+?Mn, Fe?+?Zn?+?Mn nano-chelates, and distilled water (control). The results of combined analysis of variance suggested that the effect of irrigation and foliar application of nano-chelate was significant on all traits. Water deficit stress significantly reduced the grain yield. The minimum numbers of pods per plant, number of grains per plant, 100-seed weight per plant, leaf area index, leaf chlorophyll concentration, total dry weight of plant, and the grain yield were obtained by irrigation withhold at podding stage. Foliar application of combined nano-chelates increased the soybean resistance against water shortage more considerably than the separate consumption of these elements. Under drought stress in podding stage, the application of Fe?+?Zn led to the highest yield with a mean of 2613.84?kg ha?1 where this increase was 61.1% higher than control. 相似文献
55.
M E Hamid G E Mohamed M T Abu Samra A A Hamad 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1991,44(3):273-275
In a flock of 425 female and male Nubian goats in the Khartoum Province, an outbreak of a disease causing sudden death of 18 apparently healthy goats occurred (11 females and 7 males, 3-6 years old). Adult Fasciola gigantica were found in the livers of all goats and in seven of them Cysticercus tenuicollis cysts. These organs showed necrotic and severe histopathological changes. Clostridium novyi type B was isolated from necrotic areas of all livers and found to be highly pathogenic and toxigenic to laboratory animals. The disease was diagnosed as infectious necrotic hepatitis (black disease). Faecal examination revealed the presence of F. gigantica eggs. Lymnaea natalensis snails were found to be prevalent in the water canals. As the Khartoum Province is regarded as an endemic area for black disease, routine vaccination is highly recommended for its control in goats and sheep. 相似文献
56.
E. M. Haroun O. M. Mahmoud M. Magzoub Y. Abdel Hamid O. H. Omer 《Veterinary research communications》1996,20(3):255-264
Coprological examinations on 1200 Najdi camels (Camelus dromedarius) in the Gassim region of central Saudi Arabia between October 1992 and September 1993 revealed the presence of strongyletype, Nematodirus and Strongyloides eggs. In addition, examination of the gastrointestinal tracts of 240 camels slaughtered in different abattoirs in the Gassim region from March to August 1994 revealed 11 species of helminths. Infection with gastrointestinal trichostronglyes resulted in normocytic, normochromic anaemia. Adult infected camels showed leukocytosis, a decrease in total serum protein concentration and increases in blood urea concentration and in serum creatine phosphokinase activity.Abbreviations ALP
alkaline phosphatase
- AST
aspartate aminotransferase
- CPK
creatine phosphokinase; epg, eggs per gram
- GGT
gamma-glutamyl transferase
- Hb
haemoglobin
- MCV
mean corpuscular volume
- MCHC
mean corpuscular haemoglobin concentration
- PCV
packed cell volume
- RBC
red blood cell 相似文献
57.
A. F. M. Ekramul Haque A. Hamid M. T. Islam M. Mohiuddin 《Journal of Agronomy and Crop Science》1992,168(1):61-64
Effects of seedbed condition and seeding depth on the emergence and seedling vigour of upland rice was studied. Regardless of aggregate size distribution, seeds sown at 2 cm depth gave the maximum emergence rate (80-90 %) which was reduced to 47 % for sowing at 5 cm depth. Seeding at 10 cm depth caused total failure in emergence. When planted at 2 cm depth, aggregate size produced considerable variation in the speed of emergence but caused no significant differences in final emergence count. For seeds sown at 5 cm depth, seedbed with aggregate size < 2 mm resulted in poor emergence (12 %) while with aggregates > 8 mm reduced emergence by 34 % compared with balanced proportion of larger, moderate and smaller aggregates. Neither the seedbed condition nor seeding depth caused significant variation in seedling height or seedling dry weight. 相似文献
58.
A. Hamid 《Journal of Agronomy and Crop Science》1988,161(1):11-16
Studies were carried out both in the semi-controlled environment and in the field to evaluate the influence of nitrogen and carbofuran in the growth, dry matter partitioning and yield of mungbean. Both nitrogen and carbofuran increased leaf area, leaf N content, NAR, dry matter, most of the yield attributes, and grain yield. Dry matter accumulation during the reproductive phase was significantly influenced by nitrogen and carbofuran, and method of N application. Plants treated with nitrogen fertilizer and carbofuran produced higher amount of dry matter after flowering; but gave low harvest index values compared to control. The results suggest that mungbean yield can be substantially increased through efficient dry matter partitioning employing agronomic manipulations. 相似文献
59.
60.
Hamid ME Alla KM Ahmed SS El Shiekh AE Ibrahim KE 《Journal of the South African Veterinary Association》2006,77(2):90-91
We describe a rare case of a concurrent demodectic and sarcoptic mange in a 2-year-old heifer in Khartoum, Sudan. The lesions were massive lumps of granulomatous tumour-like dermatitis with thick, nodular folds mainly covering the head, neck and shoulders. Histopathological examination of the lesions revealed the presence of both Demodex bovis and Sarcoptes scabiei. The animal died regardless of the anti-parasitic treatment it received. 相似文献