全文获取类型
收费全文 | 417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 | 20篇 |
农作物 | 37篇 |
水产渔业 | 47篇 |
畜牧兽医 | 83篇 |
园艺 | 4篇 |
植物保护 | 45篇 |
出版年
2023年 | 11篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 5篇 |
2014年 | 16篇 |
2013年 | 44篇 |
2012年 | 22篇 |
2011年 | 19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 | 6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 |
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 |
排序方式: 共有433条查询结果,搜索用时 78 毫秒
41.
C. Vijayalakshmi R. Chandra Babu S. R. Sree Rangaswamy 《Journal of Agronomy and Crop Science》1988,161(3):181-184
A field study was conducted to determine if differences in grain filling rate and duration existed in two early cultivars of rice. There is no cultivar difference in duration of grain filling and grain matured in about 30 days from anthesis in both the cultivars. The effective grain filling period in rice is only 10 days between 3rd and 13th day from anthesis. There is significant difference in grain filling rate and is positively related to grain weight. Grain filling rate is more important than duration of filling for achieving higher grain size and thus yield in rice. 相似文献
42.
Identification of readily measured traits that are associated with higher productivity of field crops is important to breeders. The objective of this study was to find out whether pod filling rate or duration of pod filling greatly decide final pod weight in greengram and blackgram. The effective pod filling duration is only 16 days in both the crops. Pod filling rate is more important than duration of pod development. Richards function is found to more closely fit the data on pod development from anthesis to maturity in both the species. 相似文献
43.
Renal and biochemical changes produced in broilers by high-protein, high-calcium, urea-containing, and vitamin-A-deficient diets 总被引:1,自引:0,他引:1
Three hundred 18-day-old male chicks (Arbor Acre) were divided into five groups of 60 each and given high-protein (42.28%), high-calcium (3.37%), urea-containing (5%), vitamin-A-deficient, or control diets to study the effect of nutritional imbalances on the development of nephritis and related biochemical changes over 15 weeks. The first four diets increased the levels of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, uric acid, and nonprotein nitrogen in serum. Blood urea was increased by only the urea diet. Hypoglycemia and a decrease in hepatic glucose-6-phosphatase were also observed in chicks fed the first four diets. The vitamin-A-deficient diet resulted in a depletion of vitamin A in the liver and kidneys. These changes were directly correlated with the prolonged feeding of experimental diets and also with the severity of nephritis and degenerative changes in various organs. It was concluded that increasing the intake of nitrogen or calcium in order to increase production may in fact have the opposite effect, leading to degenerative changes in various tissues and to nephritis. 相似文献
44.
45.
Terrell SP Sundeep Chandra AM Pablo LS Lewis DD 《Journal of the American Animal Hospital Association》2004,40(4):345-348
A 3-year-old, German shepherd dog died suddenly during cemented total hip arthroplasty. Gross necropsy findings included severe pulmonary edema and congestion as well as congestion of the liver and kidneys. Acute pulmonary embolism was suspected as the cause of death. Microscopic examination of hematoxylin and eosin-stained, formalin-fixed, and oil red O-stained frozen tissue sections confirmed the presence of large numbers of fat globules in blood vessels in the lungs, liver, and kidneys. Fat embolism during total hip arthroplasty is a common surgical complication in humans, but it is uncommon in veterinary cases and is rarely a cause of death. 相似文献
46.
Kumar KR Li L Yan M Bhaskarabhatla M Mobley AB Nguyen C Mooney JM Schatzle JD Wakeland EK Mohan C 《Science (New York, N.Y.)》2006,312(5780):1665-1669
The susceptibility locus for the autoimmune disease lupus on murine chromosome 1, Sle1z/Sle1bz, and the orthologous human locus are associated with production of autoantibody to chromatin. We report that the presence of Sle1z/Sle1bz impairs B cell anergy, receptor revision, and deletion. Members of the SLAM costimulatory molecule family constitute prime candidates for Sle1bz, among which the Ly108.1 isoform of the Ly108 gene was most highly expressed in immature B cells from lupus-prone B6.Sle1z mice. The normal Ly108.2 allele, but not the lupus-associated Ly108.1 allele, was found to sensitize immature B cells to deletion and RAG reexpression. As a potential regulator of tolerance checkpoints, Ly108 may censor self-reactive B cells, hence safeguarding against autoimmunity. 相似文献
47.
48.
Purpose
The aim of the present investigation was to document the phytotherapeutic knowledge and veterinary healthcare management practices among the Tharu tribal community of Uttar Pradesh, India and to determine the consensus of such practices, in order to evaluate the potential for new veterinary drugs of herbal origin. 相似文献49.
Singh SK Dimri U Sharma MC Swarup D Kumar M Tiwary R 《Tropical animal health and production》2012,44(1):43-48
The oxidant/antioxidant balance of rabbits naturally infected with Psoroptes cuniculi and treated with ivermectin +/− vitamins A, D3, E, and H supplementation was investigated. Two groups of seven mixed ♂ and ♀, 6-to-8 month-old New Zealand White rabbits,
diagnosed Psoroptes mites-positive by skin scraping examination and seven clinically healthy control rabbits were examined. Blood samples were
obtained on day 0 and at 28 days post-therapy to determine oxidative stress indices. On day 0, the levels of lipid peroxides
were significantly higher (P ≤ 0.01) in the Psoroptes-infected rabbits compared with the healthy controls while those of reduced glutathione and the activities of the antioxidant
enzymes glutathione peroxidase, glutathione-S-transferase, catalase, and superoxide dismutase were significantly lower (P ≤ 0.01). Vitamin supplementation of the ivermectin-treated rabbits revealed both faster clinical (14 days) and parasitological
(10 days) recovery. It was concluded that significant alteration of oxidant/antioxidant balance is a factor in the pathogenesis
of P. cuniculi infestation of rabbits, and recovery can be enhanced by combining ivermectin treatment with vitamin A, D3, E, and H supplementation. 相似文献
50.
Chandra Prakash Kala 《Journal of Sustainable Forestry》2013,32(5):360-369
This study deals with the floral diversity and distribution patterns in plant species in relation to environmental gradients in the high altitude cold desert of Ladakh, India. An extensive literature survey and field explorations were made across the different parts of Ladakh in order to create a compilation of vascular plant species. For the quantification of vegetation, a total of eight habitat types were identified and sampled using the point intercept method. In all, 647 species of vascular plants belonging to 58 families and 243 genera were documented. Asteraceae (89 species), Poaceae (66 species), Brassicaceae (54 species), and Fabaceae (43 species) were the dominant families. Astragalus was the most dominant genus as it obtained 24 species, followed by Polygonum (18 species), Artemisia (15 species), and Potentilla (14 species). Among the habitats, riverine beds contained the highest frequency of plant species, followed by narrow gorges and tablelands. The crags and ridges had the lowest frequency of plants. Relatively high water and moisture availability may be the cause of the high frequency of plant species in riverine beds and narrow gorges. The vegetation composition was influenced by elevation; however, the intensity of change reduced at >4500-m elevation. The conservation and management of high altitude cold desert vegetation are discussed based on field observations and findings. 相似文献