全文获取类型
收费全文 | 1269篇 |
免费 | 55篇 |
专业分类
林业 | 64篇 |
农学 | 48篇 |
基础科学 | 17篇 |
251篇 | |
综合类 | 40篇 |
农作物 | 139篇 |
水产渔业 | 137篇 |
畜牧兽医 | 422篇 |
园艺 | 51篇 |
植物保护 | 155篇 |
出版年
2023年 | 14篇 |
2022年 | 46篇 |
2021年 | 59篇 |
2020年 | 60篇 |
2019年 | 85篇 |
2018年 | 56篇 |
2017年 | 79篇 |
2016年 | 59篇 |
2015年 | 42篇 |
2014年 | 49篇 |
2013年 | 94篇 |
2012年 | 79篇 |
2011年 | 78篇 |
2010年 | 53篇 |
2009年 | 45篇 |
2008年 | 49篇 |
2007年 | 41篇 |
2006年 | 44篇 |
2005年 | 46篇 |
2004年 | 31篇 |
2003年 | 22篇 |
2002年 | 31篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 16篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有1324条查询结果,搜索用时 15 毫秒
891.
Seven donkeys raised in different locations in Egypt were found to have a unilateral eye showing motile white worms in the
aqueous humor. The parasites were surgically removed from the anterior chamber of the eye in five out of the seven donkeys,
and were cleared, mounted and identified as Setaria equina based on light microscopic features. The ocular infection with S. equina reported herein may be the first reported aberrant cases in the Egyptian animals. 相似文献
892.
Abd-Elmaksoud A Sayed-Ahmed A Mohamed SE Mohamed K Marei HE 《Research in veterinary science》2009,86(1):7-17
In this study, the epididymal region of the Sudani duck was investigated using histological and lectin histochemical methods. Morphologically, the epididymal region of the Sudani duck is composed of extratesticular rete testis, proximal and distal efferent ductules, a short connecting duct, and epididymal ducts. Morphometric analysis of the epididymal region of Sudani duck revealed that the efferent ductules predominate in relation to the epididymal ducts. The distribution of sugar moieties within the epididymal region of the Sudani duck was investigated using ten different fluorescein isothiocyanate (FITC) conjugated lectins. In the rete testis epithelium, only PHA-L showed a positive reaction. Efferent ductules in contrary exhibited a wide range of lectin affinity whereas six positive lectins (Con A, LCA, PNA, WGA, PHA-L, PHA-E) were observed. In the connecting and epididymal ducts, four lectins (Con A, WGA, PHA-L, PHA-E) were also detected. GSA-I, UEA-I, and LTA were at all not evident in the epididymal region of the Sudani duck. In conclusion, the correlation between the large areas of the epididymal region occupied by the efferent ductules and the wide range of sugar affinity of this portion may confirm the speculation that efferent ductules might be the primary site of fluid reabsorption in the epididymal region of Sudani duck. 相似文献
893.
Elsayed A. Elkhatib Ahmed M. Mahdy Mohamed M. ElManeah 《Journal of Soils and Sediments》2013,13(1):94-105
Purpose
Recent research has focused on using water treatment residuals (WTRs) as cost-effective materials to remove potential environmental contaminants. To better understand and predict how WTRs affect the mobility and retention of nickel (Ni) in soils with time, it is crucial that the kinetics and thermodynamics of these reactions be understood. Such information is lacking in the literature and would aid in evaluating the suitability of WTR as a soil amendment for adsorbing Ni contaminant. Accordingly, we focused on investigating the retention of Ni in differing soils and the subsequent influence of WTR application on Ni retention.Materials and methods
To examine the effects of WTR application on the characteristics of Ni retention, equilibrium, and kinetics, sorption batch experiments were performed on three soils having different properties. The sorption data were applied to the first-order kinetic model, and the Arrhenius equation was used to determine the thermodynamic parameters.Results and discussion
The quantity of Ni sorbed by the soils followed the trend Typic Torrifluvent > Typic Calciorthids > Typic Torripsamment. Soil sorption isotherms shift toward a higher sorption of Ni indicating addition of more sorption sites as a result of WTRs’ application. Data generated at different temperatures for soils and WTR-amended soils fitted well to Freundlich isotherm and first-order kinetic models. The energy of activation (E a) and enthalpy (ΔH #), entropy (ΔS #), and free energy of activation (ΔG #) related to Ni sorption were calculated using the Arrhenius equation. The activation energy (E a) values (51.65–130.0 kJ mol?1) and the positive ΔH # values characterize Ni sorption process onto the sorbents studied as chemisorption with an endothermic nature. The large negative ΔS # values (?262 to ?290 J?mol?1) and the large positive ΔG # values (88.11–89.14 kJ mol?1) indicate the involvement of an associative mechanism in the Ni sorption process.Conclusions
WTR addition has led to an overall increase in Ni sorption by the amended soils. Such increase in Ni sorption provides evidence that WTR has the potential for land application as a Ni sorbent in soil remediation techniques. The sorption capacity of the soils and WTR-amended soils enhanced with an increase in temperature. Therefore, to truly understand the potential fate and mobility of Ni in the natural environment, temperature, in particular, should be considered. 相似文献894.
Naglaa Hassan Mohsen Mohamed Elsharkawy Remedios Villajuan-Abgona 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):208-214
Binucleate Rhizoctonia (BNR) W7 was evaluated for the efficacy to control damping-off disease in cucumber seedlings. Results revealed that Lobate appresoria and dome-shaped infection cushion were produced by virulent Rhizoctonia solani C9 AG4 on the surface of the cucumber seedling hypocotyls, causing damping-off, 12 h after inoculation. A significant positive correlation was observed between disease severity rating and number of infection cushions (r = 0.94) and appresoria (r = 0.97) on the hypocotyls of seedlings inoculated with virulent R. solani C9 alone. Inoculation of a nonpathogenic species of BNR prior to virulent R. solani significantly reduced the number of appresoria on hypocotyls surface and inhibited the formation of infection cushions that accompanied by highly significant (P ≤ 0.01) reduction in disease severity in comparison with seedling inoculated with R. solani C9 alone. Formation of mucilaginous material upon recognition of the nonpathogenic isolate of BNR followed by hyphal lysis of BNR W7 6 h after inoculation was responsible for reduction in appresorium formation and complete inhibition of infection cushion formation. However, the number of infection structures produced on cucumber was not significantly different for hypocotyls of seedlings inoculated with R. solani C9 with and without the nonpathogenic BNR W7. 相似文献
895.
Rym Trimech Yosr Zaouali Abdennacer Boulila Lotfi Chabchoub Ismail Ghezal Mohamed Boussaid 《Genetic Resources and Crop Evolution》2013,60(5):1621-1628
The morphological variation and the systematical status of 28 traditional melon including two ancient varieties collected from different geographical and bioclimatic areas of Tunisia were assessed based on 34 qualitative and quantitative traits. Yellow Canary was used as a reference variety. Significant differences among accessions within and among sites of collection were revealed for the majority of traits. The accessions from the Sahel were more polymorphic than those from Tozeur’s oasis. However, the classification of the local accessions according to Munger and Robinson’s varietal groups did not allow clear segregation of several of them because of their high heterogeneity. The principal component analysis (PCA) performed on all measured traits, allowed a distinction among the introduced varieties clustered according to their varietal group, and the local accessions grouped separately according to their geographical origin and bioclimatic zone. Mahalanobis distances among PCA’s groups were significant. The correlation found between Mahalanobis distance matrix and geographical distance matrix among origins corroborated isolation per distance. Conservation strategies should be made appropriately according to origins. Accessions from the Sahel showing the highest polymorphism within and among sites of collection should be firstly preserved. 相似文献
896.
Ajmi Larbi Kamel Gargouri Mohamed Ayadi Ali Ben Dhiab Monji Msallem 《Journal of plant nutrition》2013,36(14):2083-2094
Boron (B) foliar treatments (300 mg L?1 as Solubor DF) were applied at two different dates in 2006 and 2007, prior to flowering and just after fruit set, on olive (Olea europaea L.) trees with no visual symptoms of B deficiency. Leaf B level increased after the first application as compared to control (?B). After July treatment, leaf B levels in ?B and +B treated trees increased when compared to the first sampling date. Foliar B application did not significantly affect vegetative growth in either year. During the first year of study (considered as an “on year”), B application had no significant effect on several phenological characteristics including fruit set, yield oil contents and oil quality. In the second year (“off year”), B sprays improved blooming rate, which increased from 20% in ?B to 30% in + B treated trees, and olive yield, which increased by 27% in response to B. 相似文献
897.
Saad Drissi Abdelhadi Aït Houssa Fouad Amlal Khalid Dhassi Mohamed Lamghari Abdelwahed Maataoui 《Journal of plant nutrition》2013,36(17):2266-2272
This study was designed to determine the adequate copper (Cu) foliar spray concentration to correct Cu deficiency on barley (Hordeum vulgare L.) when grown in a calcareous soil. Five Cu foliar spray solution levels were tested (0% or control; 0.03%, 0.06%, 0.13%, and 0.33%). Copper was applied in the sulfate form at the early boot stage. The results showed that Cu flag leaf concentration was increased with the highest Cu application (0.33%), while Cu concentration in the grain was increased with a spray of 0.03%. An antagonism between Cu, Zn, and Fe leaf concentration was observed. Grain yield and harvest index showed a linear positive response to Cu foliar spray concentrations. A significant increase of 19.6% on grain yield was recorded with a foliar spray 0.33% of Cu. 相似文献
898.
Hafidh Akkari Kais Rtibi Fatma B’chir Mourad Rekik Mohamed Aziz Darghouth Mohamed Gharbi 《Veterinary research communications》2014,38(3):249-255
Occurrence of anthelmintic resistant strains of helminths is increasing. The aim of this study was to evaluate the in vitro anthelmintic activity of Artemisia campestris in comparison to albendazole against Haemonchus contortus of sheep. In this respect, in vitro anthelmintic activities of crude aqueous and crude ethanolic extracts of aerial parts of A. campestris were investigated on eggs and adults of Haemonchus contortus. Chemical analyses revealed that overall profile of both extracts samples were dominated by flavonoids among them quercetin and apigenin derivatives were the most abundant phenolics constituents. Both extract types completely inhibited egg hatching at a concentration close to 2 mg/ml. Lethal concentration 50% of A. campestris ethanolic and aqueous extracts were 0.83 and 1.00 mg/ml respectively (p?0.05). The ethanolic extract showed better in vitro activity against adult parasites than the aqueous extract in terms of the paralysis and/or death of the worms at different hours post-treatment. Dose dependent activity was also observed for both extract. After 8 and 24 h of exposure, the ethanolic extract induced 91.3 and 100% mortality at the highest tested concentration respectively, while the aqueous extract induced 3.22 and 70.96% at the same concentration respectively. To our knowledge, these results depict for the first time that A. campestris possesses in vitro anti-Haemonchus contortus properties. 相似文献
899.
900.
Assem Mohamed Safwat Luis Sarmiento-Franco Ronald Santos-Ricalde Duilio Nieves 《Tropical animal health and production》2014,46(7):1193-1198
This experiment was carried out to evaluate the effect of including either Leucaena leucocephala (LLM) or Moringa oleifera leaf meal (MOLM) as tropical feed resources at two levels (30 or 40 %) on growth performance, carcass traits, and economical efficiency of growing rabbits. A total of 60 California growing rabbits were randomly distributed into five experimental groups, each consisting of 12 rabbits and were allocated individually; the groups were control, 30 % LLM, 40 % LLM, 30 % MOLM, and 40 % MOLM. The experimental period lasted from 6 to 12 weeks of age. The results showed that rabbits fed control and 30 % MOLM diets had significantly the highest final body weight and daily weight gain being 2,040 and 2,000 g and 31.6 and 30.6 g/day, respectively. Similarly, the best feed conversion ratio was associated with 30 % MOLM and control groups (3.2 and 3.4), while the worst value was for 40 % LLM group (5.2). MOLM treatments recorded significantly the highest dressing percentage along with control group. The inclusion of MOLM by 30 and 40 % improved the economical efficiency (2 and 1.5) in comparison with the control group (1.1). The results suggest that MOLM can be included in growing rabbit diets up to 40 % without any adverse effect on growth performance or carcass traits with higher economical efficiency of growing rabbits. 相似文献