全文获取类型
收费全文 | 425篇 |
免费 | 16篇 |
专业分类
林业 | 43篇 |
农学 | 47篇 |
基础科学 | 6篇 |
101篇 | |
综合类 | 21篇 |
农作物 | 40篇 |
水产渔业 | 49篇 |
畜牧兽医 | 86篇 |
园艺 | 4篇 |
植物保护 | 44篇 |
出版年
2023年 | 11篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 5篇 |
2014年 | 17篇 |
2013年 | 44篇 |
2012年 | 24篇 |
2011年 | 20篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 12篇 |
2000年 | 3篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1958年 | 2篇 |
1952年 | 1篇 |
排序方式: 共有441条查询结果,搜索用时 296 毫秒
141.
Hematological, biochemical, histoenzymological, and histopathological changes in serum and tissues were studied in chickens during outbreaks of nephritis. Hematological studies revealed normocytic-normochromic anemia characterized by increased total erythrocyte counts, hemoglobin, packed cell volume, and erythrocyte sedimentation rate. Albumin-to-globulin ratio and sodium levels in serum, glucose in blood, and alkaline phosphatase and glucose-6-phosphatase in liver and kidneys were decreased. Glutamate pyruvate transaminase, uric acid, non-protein-nitrogen, and potassium levels in serum were increased. No significant change in the calcium, phosphorus, and total protein levels in serum was observed. These changes were directly related to the severity of the nephritis. 相似文献
142.
R. P. Bansal R. C. Joshi B. Sharma S. K. Bandyopadhyay U. Chandra 《Tropical animal health and production》1986,18(3):133-136
Summary The single radial hemolysis [SRH] test was employed for detection of rinderpest antibodies in post-vaccinated serum samples
as also in serum samples from animals recovered from rinderpest infection. The results were compared with counterimmunoelectrophoresis
[CIE] and serum neutralisation [SN] tests. The CIE test was found to be more sensitive than SRH but because of ease and simplicity
SRH can also be used for monitoring antibody development after vaccination.
Resumen Se utilizó la prueba radial sencilla de hemólisis (RSH) para detectar anticuerpos de rinderpest, en muestras de suero de animales vacunados y recuperados de la enfermedad. Los resultados se compararon con las pruebas de contrainmunoelectroforésis (CIE) y sero neutralización (SN). La prueba CIE fue más sensitiva que la RSH, pero debido a la sencillez de manejo, se recomienda la RSH para medir el nivel de anticuerpos post vacunales.
Résumé Le test d’hémolyse radiale simple (HRS) a été utilisé pour la détection des anticorps antibovipestiques dans des échantillons de sérums après vaccination et aussi dans des échantillons de sérums d’animaux convalescents. Les résultats ont été comparés avec les tests de contre-immunoélectrophorèse (CIE) et de séroneutralisation (SN). On a trouvé que le test CIE est plus sensible que le HRS mais par suite de son aisance et de sa facilité, le HRS peut aussi être employé pour suivre le développement des anticorps après vaccination.相似文献
143.
M. Seetha Rani R. Chandra Babu M. Moosa Sheriff R. K. Pallikonda Perumal 《Journal of Agronomy and Crop Science》1990,164(2):81-84
The allelopathic potential of shoot and root leachates of seven weed species was assessed using sorghum and blackgram as test crops. Weeds differed significantly among themselves in their allelopathic effect. Shoot leachates of weeds, in general, showed more allelopathic effect than their root leachates. Phenolic content of weed leachates has positive association with the allelopathic potential of the weed species. 相似文献
144.
S. Chandra 《Agricultural Systems》1982,9(1):1-13
This paper shows how a detailed analysis of production and consumption behaviour of subsistence and semi-subsistence farmers can be used for farm planning and development of rural communities. The study is based on a survey of a sample of Fijian and Indian semi-subsistence farmers in the Sigatoka Valley, Fiji. The results showed marked differences in the dietary patterns of the two communities and in the sources of food energy and protein amongst the various food commodities. The Indians were more efficient than the Fijians in meeting the food needs from their farms. The Fijians tended to purchase more store foods and also purchased more expensive sources of food energy and protein to supplement their diet. Finally, the results of this study are used to indicate pathways for national food policies for Fiji and other developing nations. 相似文献
145.
The environmental benefits of water table management (WTM), as a method to reduce nitrate pollution, are well known. However,
there are few published studies on the effects of WTM on water use efficiency (WUE). This paper highlights the agronomic interest
of WTM for increasing WUE of irrigated grain corn production. A field study was conducted in 2001 and 2002 at a large scale
WTM research facility in Québec, Canada. The region experienced periods of drought during the two growing seasons. This study
shows that, by keeping the water table at 0.80 m below the soil surface, there were on average 35% increases in grain corn
yields, compared to conventional free drainage. The WUEs obtained with WTM (5.1 kg m−3 in 2001 and 7.1 kg m−3 in 2002) indicate that the method is generally more water efficient than conventional sprinkler and furrow irrigation. The
WUE of WTM also compares well with that of water conservation methods such as alternate furrow irrigation and deficit sprinkler
irrigation. Moreover, WTM requires low inputs in terms of equipment, energy, and labour, because it makes use of existing
subsurface drainage systems, which are widespread in Eastern Canada due to the region's soils and climate, and because of
its design, which does not necessitate high-pressure pumps and allows for automated management. Hence, WTM appears to be an
interesting alternative to conventional irrigation methods due to its combined environmental and agronomical benefits. 相似文献
146.
147.
Anirban Biswas Saroni Biswas Rama Venkata Srikanth Lavu Prakash Chandra Gupta Subhas Chandra Santra 《Paddy and Water Environment》2014,12(3):379-386
Rice is prone to arsenic accumulation compared to other cereals as typically grown up under waterlogged situation favoring arsenic mobility. Arsenic in rice depends on arsenic availability to plants from irrigation water, even differs among cultivars and their plant parts. Present study was concentrated on arsenic accumulation in various plant parts of five common rice cultivars grown using irrigation water from different water sources in various fields in arsenic-endemic region. Additionally, dose response experiment under laboratory net house was conducted on the same cultivars excluding open environmental factors. The common cultivars were categorized according to high to low arsenic accumulator in rice grain, straw and root parts. The cultivar Shatabdi has shown highest arsenic accumulation in rice grain compared to other rice cultivars in fields and when grown at various soil arsenic doses. In field samples, a highest grain arsenic concentration ranged between 0.69 ± 0.04 and 0.78 ± 0.12 mg kg?1 for Shatabdi, whereas lowest grain arsenic concentration ranged between 0.37 ± 0.07 and 0.41 ± 0.07 mg kg?1 for the cultivars GB3 and Lalat. Speciation study detected more inorganic arsenic than organoarsenicals with a trend of arsenite > arsenate > DMA > MMA, which would be problem for consumers. The concluding remark is the characterization of common rice cultivars according to arsenic concentration to highlight an important remediation strand by changing to low arsenic cultivar. 相似文献
148.
An ion microscope has been used to demonstrate that the calcium ion is present in the amyloplasts of root-cap cells of corn, pea, and lettuce. The localization of calcium in the gravity-sensing organelle suggests a possible role of calcium in the gravity-sensing mechanism of plant roots. 相似文献
149.
Single tobacco callus cells with or without tobacco mosaic virus inclusion bodies from systemically infected Nicotiana tabacum plants were grown in microcultures. The culture medium consisted of mineral salts and sucrose; it also contained coconut milk. Out of 100 inclusion-bearing cells and 150 inclusion-free cells, 10 and 70 cultured cells divided; eventually 5 and 65 cells, respectively, formed single cell clones. The 5 clones derived from inclusion-bearing cells, and all but 3 of 40 clones from inclusion-free cells, showed virus inclusions in somne cells. The virus could not be detected in three inclusion-free clones by local lesion assay. The results suggest single-cell culture methods for differentiating virus-free plants from cells of pathogen-infected plants. 相似文献
150.
Summary A new type of pollen sterility has been observed in commercial potatoes (Solanum tuberosum L.) where abundant, non-aborted, apparently normal-looking but non-functional pollen grains are produced. 相似文献