全文获取类型
收费全文 | 343篇 |
免费 | 24篇 |
专业分类
林业 | 12篇 |
农学 | 13篇 |
基础科学 | 7篇 |
103篇 | |
综合类 | 8篇 |
农作物 | 80篇 |
水产渔业 | 56篇 |
畜牧兽医 | 53篇 |
园艺 | 10篇 |
植物保护 | 25篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 24篇 |
2018年 | 26篇 |
2017年 | 46篇 |
2016年 | 37篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 38篇 |
2012年 | 22篇 |
2011年 | 35篇 |
2010年 | 21篇 |
2009年 | 2篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 1篇 |
排序方式: 共有367条查询结果,搜索用时 0 毫秒
21.
Anabat Mohammad Mohebi Sheidai Masoud Riahi Hossein Koohdar Fahimeh 《Genetic Resources and Crop Evolution》2022,69(2):855-870
Genetic Resources and Crop Evolution - The genus Crocus of the family Iridaceae is a monophyletic genus with over 100 species. Due to the high degree of hybridization and the changes in the number... 相似文献
22.
Pomegranate fruit is an important source of potentially healthy bioactive compounds and mineral nutrients. Changes in total phenolic compound, concentrations, and levels of macronutrients (P, K, N, Mg, Ca and Na) and micronutrients (Zn, Cu, Mn, Fe and B) in arils and peel of pomegranate fruit were recorded from 10 days after full bloom until harvest. Total phenolics levels increased at early stage of growth both in peel and arils of fruit, but thereafter generally decreased during maturation and reached to 3.70 and 50.22 mg g−1 of dry weight in arils and peel, respectively, at harvest. The amount of total phenolics in peel was markedly higher than arils of pomegranate fruit. The concentration of most elements in arils and peel decreased during fruit growth and development. At harvest the relative order of concentration of macronutrients both in arils and peel was K > N > Ca > P > Mg > Na. The concentration of most micronutrients was greater in the arils than in the peel especially in early season. The relative order of concentration of micronutrients in arils was B > Fe > Zn > Cu > Mn. The accumulation of all the macro- and microelement within the fruit also increased during fruit growth and development. These results provide important data on total phenolics and macro- and micronutrient changes during fruit growth and development, emphasizing that pomegranate fruit can be a good source of bioactive compounds and minerals. 相似文献
23.
Shamsuddin M Goodger WJ Hossein MS Azizunnesa Bennett T Nordlund K 《Tropical animal health and production》2006,38(2):131-140
Identified economic opportunities for planning interventions greatly increase farmers’ compliance with an extension programme.
We investigated opportunities for interventions to increase dairy farmers’ income in four areas of Bangladesh, including the
districts of Mymensingh, Khulna-Satkhira, Sirajgonj-Pabna and Chittagong. The data were collected from 1440 dairy farms at
a one-day visit and were summarized as the difference between management targets and each herd’s calculated management indices.
The average number of lactating cows, feed cost as a percentage of income from milk, milk sold as percentage of milk produced,
lactating cows as a percentage of mature cows, and lactating cows as a percentage of total cattle varied from 1.5 to 3.4,
from 52.5% to 92.1%, from 78.7% to 92.6%, from 81.9% to 86.7% and from 34.3% to 37.7%, respectively. The average age at first
calving, calf production interval, lactation length, and milk production were 35.0–44.3 months, 14.0–17.6 months, 249–286
days and 3.5–7.2 litres, respectively, depending on the locality. The average cost for producing 100 litres of milk was 18.9–35.1
US dollars. The production cost increased when daily milk production per cow decreased (r2 = 0.43–0.55). Management improvements directed towards increasing average milk production per cow per day, increasing lactation
length, decreasing age to first calving, and decreasing calf production interval could expect to yield an average income increase
up to a range of 676.3–1730.6 US dollars depending on the milk-producing area. 相似文献
24.
Hossein Mohammadi Mohammad Moradi Shahrebabak Mahmood Vatankhah Hossein Moradi Shahrebabak 《Tropical animal health and production》2012,45(1):185-191
Genetic parameters and genetic trends for birth weight (BW), weaning weight (WW), 6-month weight (6MW), and yearling weight (YW) traits were estimated by using records of 5,634 Makooei lambs, descendants of 289 sires and 1,726 dams, born between 1996 and 2009 at the Makooei sheep breeding station, West Azerbaijan, Iran. The (co)variance components were estimated with different animal models using a restricted maximum likelihood procedure and the most appropriate model for each trait was determined by Akaike’s Information Criterion. Breeding values of animals were predicted with best linear unbiased prediction methodology under multi-trait animal models and genetic trends were estimated by regression mean breeding values on birth year. The most appropriate model for BW was a model including direct and maternal genetic effects, regardless of their covariance. The model for WW and 6MW included direct additive genetic effects. The model for YW included direct genetic effects only. Direct heritabilities based on the best model were estimated 0.15?±?0.04, 0.16?±?0.03, 0.21?±?0.04, and 0.22?±?0.06 for BW, WW, 6MW, and YW, respectively, and maternal heritability obtained 0.08?±?0.02 for BW. Genetic correlations among the traits were positive and varied from 0.28 for BW–YW to 0.66 for BW–WW and phenotypic correlations were generally lower than the genetic correlations. Genetic trends were 8.1?±?2, 67.4?±?5, 38.7?±?4, and 47.6?±?6 g per year for BW, WW, 6MW, and YW, respectively. 相似文献
25.
L. Riahi N. Zoghlami K. El-Heit V. Laucou L. Le Cunff J. M. Boursiquot T. Lacombe A. Mliki A. Ghorbel P. This 《Genetic Resources and Crop Evolution》2010,57(2):255-272
Three gene pools representative of Vitis vinifera L. subsp. vinifera (=subsp. sativa Beger) growing in the Maghreb regions (North Africa) from Tunisia (44), Algeria (31) and Morocco (18) and 16 wild grape accessions
(Vitis vinifera L. subsp. sylvestris (Gmelin) Beger) from Tunisia were analysed for genetic diversity and differentiation at twenty nuclear microsatellites markers
distributed throughout the 19 grape chromosomes. 203 alleles with a mean number of 10.15 alleles per locus were observed in
a total of 109 accessions. Genetic diversities were high in all populations with values ranging from 0.6775 (Moroccan cultivars)
to 0.7254 (Tunisian cultivars). F
st pairwise values between cultivated grapevine populations were low but found to be significantly different from zero. High
F
st pairwise values were shown between wild and cultivated compartments. Two parent offspring relationships, two synonyms and
two clones of the same cultivar were detected. The rate of gene flow caused by vegetative dissemination of cultivated grapevine
plants was not sufficient to genetically homogenise the pools of cultivars grown in different regions. The Neighbour Joining
cluster analysis showed a clear separation according to geographical origins for the cultivated grapevines gene pools and
revealed a high dissimilarity between cultivated and wild grapevine. However, three cultivars (Plant d’Ouchtata 1, Plant de
Tabarka 3 and Plant d’Ouchtata 3) are very close to wild accessions and may result from a hybridisation between cultivated
and wild accessions. The high level of differentiation between cultivated and wild accessions indicates that the cultivated
accessions do not derive directly from local wild populations but could mostly correspond to imported materials introduced
from others regions during historical times or derived from crossing between them. 相似文献
26.
Arash Omidi Hossein Ansari nik Mahmood Ghazaghi 《Tropical animal health and production》2013,45(2):431-434
Ten blue-neck male ostriches (Struthio camelus) were fed Prosopis farcta beans throughout a 30-day experiment. Blood samples were collected from ostriches on days 0 and 30 to measure levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, total serum protein, albumin, globulin, cholesterol, calcium, inorganic phosphorus, the activity of aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferase (γ-GT). From days 0 to 30, HDL cholesterol, total protein, and globulins levels increased significantly whereas LDL cholesterol, inorganic phosphorus, and γ-GT activity decreased significantly. 相似文献
27.
In this research experiment, two commercial onion cultivars (Allium cepa L., cvs. Dorrcheh and Cebolla Valenciana) were grown in sand culture and exposed to two levels of selenium (Se) (0 and 25?µM) and two levels of sulfate (1 and 3?mM). According to the results obtained, addition of 25?µM Se in combination with 3?mM sulfate was not only effective in significant increase of onion bulb yield, but it significantly increased Se concentration of bulb. By considering the average consumption of onion in central Iran, the daily intake of Se via consumption of Se-biofortified onion is estimated to be 68.4–77.2?µg in spring and summer and 72.6–117.1?µg in fall and winter. These amounts of daily intakes of Se is higher than the sufficient levels of Se recommended by world health organization (WHO) but less than the maximum tolerable level of Se (400?µg Se per day) for human. 相似文献
28.
OBJECTIVE: To assess the effects of socio-economic status (SES) on BMI, waist:hip ratio (WHR) and waist circumference (WC) in a group of Iranian women. METHODS: A cross-sectional study was conducted on 888 women in Sistan and Baluchestan Province. SES was measured using level of education. In addition, parity, marital status and physical activity were assessed. Standardized measurements were taken, BMI and WHR were calculated. RESULTS: Low education level was a strong determinant of overweight and obesity among Iranian women. After controlling for age, women with higher education level had significantly lower BMI, WC and parity. Multiple linear regression analysis found a significant negative association of BMI and WC with education level and a significant positive association of BMI and WC with parity. Significant factors associated with obesity by a logistic regression model were education level (OR for university graduates v. illiterate or low literacy levels: 1.00 v. 3.70; P = 0.01), living with spouse (OR for married v. single subjects: 1.00 v. 0.15; P = 0.05), parity (OR for more than five v. less than two pregnancies: 1.00 v. 0.34; P = 0.03) and WC (OR for < 0.88 cm v. > or = 0.88 cm: 1.00 v. 11.20; P = 0.001). CONCLUSION: The present study revealed that educational level, multiple pregnancies, marital status and lack of exercise are some possible explanations for the obesity among Sistan and Baluchestan women. 相似文献
29.
Sayed Mohammad Ali Jalali Haji‐abadi Nasrollah Mahboobi Soofiani Ali Asghar Sadeghi Mohammad Chamani Gholam Hossein Riazi 《Aquaculture Research》2010,41(11):1582-1591
This study was carried out to investigate a possible protein‐sparing action of l ‐carnitine and ractopamine in rainbow trout, Oncorhynchus mykiss. An 8‐week feeding trial was carried out to evaluate the effects of supplementation of three levels of l ‐carnitine (0, 1 and 2 g kg?1) and two levels of ractopamine (0 and 10 mg kg?1) on growth performance, fillet fatty acid compositions and blood biochemical parameters in a 3 × 2 factorial experimental design. Ractopamine and 1 g kg?1 carnitine improved the specific growth rate (1.03% and 1.05% day?1), feed conversion ratio (FCR, 1.3 and 1.29), protein efficiency ratio (PER, 1.88 and 1.85) of fish and crude protein (73.5 and 73.8) content of fish fillet. l ‐carnitine and ractopamine increased the levels of albumin, total protein and globulin in the serum of fish. Apart from eicosapentaenoic acid and docosahexaenoic acid, other fatty acids of fish fillet were increased by ractopamine, while total saturated fatty acids were almost intact. However, the total n‐3 poly unsaturated fatty acids were reduced by l ‐carnitine supplementation (P<0.05). The present study showed that 1 g kg?1l ‐carnitine and 10 mg kg?1 ractopamine each can improve the performance of rainbow trout and their combination in diet could enhance the protein level and change the fatty acids profile in fillet muscle. 相似文献
30.