全文获取类型
收费全文 | 251篇 |
免费 | 13篇 |
专业分类
林业 | 19篇 |
农学 | 12篇 |
基础科学 | 2篇 |
72篇 | |
综合类 | 14篇 |
农作物 | 50篇 |
水产渔业 | 23篇 |
畜牧兽医 | 41篇 |
园艺 | 5篇 |
植物保护 | 26篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 23篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 24篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 28篇 |
2012年 | 13篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有264条查询结果,搜索用时 31 毫秒
81.
Fatima Benlboukht Loubna El Fels Rachid Bouamri Soumia Amir 《Compost science & utilization》2016,24(3):208-218
Changes in the structural composition of fulvic acids were followed during composting of tannery solid waste after neutralization of its acidity by ammonium or by lime. Different techniques (elemental analysis, Fourier transform infrared (FTIR), 13C-NMR spectroscopy) were applied. During both trials of composting, a decrease of carbon and increase of oxygen occurred, which originated from strong microbial oxidation and preservation of some structures during composting. In fact, Nuclear Magnetic Resonance (NMR) spectra showed the preservation of anomeric or tannin structures around 105 ppm. The infrared (IR) spectral data showed a decrease in the intensity of COO? group bands (1623 and 1399.5 cm?1); this is correlated with a decrease of fulvic acid levels. The variations observed in NMR spectra could be explained by the involvement of COO? groups of certain structures in polycondensing to form humic acids. The fulvic acids remain composed of less polycondensed structures with a –COOH extremity, as supported by a decrease of the C/H ratio. In contrast, in the trial with addition of ammonia a slight increase in N content occurred, a decrease in absorbance in the 1730–1000 cm?1 regions compared to the absorbance around 3400 cm?1, and a strong decrease of carboxyl carbon in the 13C-NMR spectra. 相似文献
82.
Mohebbi-Fani M Mirzaei A Nazifi S Shabbooie Z 《Tropical animal health and production》2012,44(2):259-265
This study assessed the changes of plasma vitamin A, E, and C and the lipid peroxidation status of sheep during breeding and
pregnancy under drought conditions. The study was conducted on 105 cross-bred fat tailed ewes, 3–5 years old with body condition
scores (BCS) of 2.5 to 3.5. The ewes were grazing on medium-to-low quality forages during summer and low quality forages within
the succeeding months and had ad libitum access to a mixture of alfalfa hay (40%) and wheat straw (60%) in the afternoons. From 3 weeks before breeding till 1 month
after the introduction of rams, 300 g of barley grain/head/day was offered to the ewes and then the supplemental grain was
reduced to 100 g/head/day. For better synchronization of estrus cycles in ewes, they were isolated from the rams for at least
2 months and then kept in close proximity of the rams for 1 week before the introduction of the rams to the ewe flock. Then,
whole blood samples were collected on days 1, 7, 21, and 120 after ram introduction. Vitamins A, E, and C were measured in
plasma. Malondialdehyde (MDA) was measured in the hemolysate as a biomarker of lipid peroxidation. Plasma progesterone (P4)
was measured in the samples of day 120 for assessing pregnancy status of the ewes. Vitamins A and C showed continuous and
significant declines (P < 0.05) through days 1 to 120. Vitamin E declined only during the first 21 days of the study and remained almost constant
till day 120. MDA concentration increased significantly at day 21. An elevated concentration of MDA was also detected at day
120. The difference between days 21 and 120 was not significant (P > 0.05). A positive correlation between vitamins E and C was detected at day 120 (r = 0.349, P < 0.01). Age and BCS did not affect the patterns of changes. Assuming that the ewes with P4 concentrations ≥2.5 ng/ml were
pregnant, 95 out of 105 ewes (90.5%) were pregnant at day 120 of the study. Under the conditions of the present study with
medium-to-low quality pastures as the main sources of feed, ewes of various ages and body conditions may suffer from oxidative
stress during breeding and pregnancy. 相似文献
83.
Amine Moubarik Bertrand Charrier Fatima Charrier Antonio Pizzi Ahmed Allal 《Annals of Forest Science》2009,66(1):109-109
84.
Fumigant activity of essential oil vapors distilled from Carum copticum C. B. Clarke and Vitex pseudo-negundo Hand I. MZT. was tested against eggs, larvae and adults of Callosobruchus maculatus (F.). Fumigant toxicity was assessed at 27 ± 1°C and 60 ± 5% RH, in dark condition. The influence of different concentrations of
the essential oil vapors on egg hatchability, larval and adult mortality was significant. Data probit analysis showed that
lethal concentration of the essential oil to kill 50% of the population (LC50) for egg, larvae and adult were found to be 1.01, 2.50 and 0.90 μl/l air of C.
copticum oil, followed by 2.20, 8.42 and 9.39 μl/l air essential oil of V. pseudo-negundo, respectively. Between these essential oils, C. copticum was almost more toxic than V. pseudo-negundo on all growth stages of C. maculatus. The present study suggests that essential oils from these medicinal plants may be potential grain protectants as botanical
alternative fumigants and could be used in the management of various life stages of C. maculatus. 相似文献
85.
Noreen Fatima Muhammad Shahid Ghulam Abbas Mubshar Hussain Muhammad Nafees 《Journal of plant nutrition》2018,41(12):1555-1565
Salinity is the major environmental stress that affects the growth and productivity of plants. The present study was conducted to determine the effect of salinity on growth and ions uptake by moringa (Moringa oleifera L.) plant. The experiment was carried out in two phases. Initially, a germination test was conducted in the laboratory under the different salinity levels (control, 5, 10, 15, and 20 dS m?1) and found that moringa seeds were germinated only at 5 and 10 dS m?1 salinity levels, and no germination occurred at higher salinity levels (15 and 20 dS m?1). The experiment was laid out in a completely randomized design (CRD) with five replications. In the second phase, three-week old nursery grown plants of moringa were shifted in pots under the five salinity levels (control, 5, 10, 15, and 20 dS m?1). The experiment was laid out in CRD and replicated four times. In pot experiment, the root, shoot length, and dry weights were significantly affected by increasing the salinity levels. The uptake of K+ and Ca2+ was highly affected at different salinity levels as compared to control and Na+ ions accumulation was higher in roots rather than shoot. The results reveal that moringa plant can germinate, survive, and can be cultivated in areas with moderate saline condition. 相似文献
86.
Walnut (Juglans regia L.), is one of the main economic fruit species in the world and is rich in nutritious substances. In order to obtain superior walnut genotypes, a set of seedling walnut genotypes were evaluated and their results were recorded. The range of nut length was between 25.57 and 47.77 mm. Also, the ranges of nut weight, kernel weight and kernel percentage varied from 5.35 to 21.31 g, 2.49 to 11.15 g and 37.27 to 66.29%, respectively. Simple correlation analysis showed significant positive and negative correlations between some of the measured traits. Principal component analysis reduced the evaluated traits into the seven main components, which explained 71.71% of the total variance. Bi-plot analysis performed using the first two components, distributed the genotypes into four sides of the plot. Based on the present results, a high variation was observed among the trees, indicating a high potential of the studied germplasm to select the superior genotypes. According to the present research, 57 genotypes with having the highest nut weight and kernel weight, as well as bright color of the kernel, were recognized as superior genotypes and can be used to establish the new orchards or improve cultivars. 相似文献
87.
Md. Arif Chowdhury Fatima-Tuz- Zahra Md. Farhadur Rahman Kamrul Islam 《Small-Scale Forestry》2018,17(4):535-553
Chittagong Hill Tracts (CHTs) in Bangladesh covers about 50% of the country’s natural forest resources, providing sources of food, fuel-wood, medicinal plants, timber and water supply to the ethnic communities living in the area. The ethnic communities in CHTs have been managing a small patch of forest known as a village common forest (VCF) adjacent to their village following a community based forest management approach. Taking a case study of Komolchori VCF, this study examined dependency of community people on VCF resources, their conservation-related attitudes and awareness, indigenous management, and forest phyto-sociological structure. A survey and focus group discussions were conducted among the settlers and non-settlers in Thana Chandra para and Jaduram para villages of the Komolchori VCF. Key informant interviews were conducted with two non-government organizations (NGOs) and the headman in the study area. To assess phyto-sociological structure of vegetation, 25 quadrats (10 m?×?10 m) were laid out randomly. Results revealed that non-settlers were more inclined towards VCF conservation and women played a crucial role as they were directly involved in forest products and water collection. Soil erosion caused by shifting cultivation has made community people more aware of forest degradation. Training program provided by NGOs on different horticultural techniques and a “Saving-Credit program” improved livelihood conditions and reduced pressures on VCF resources. Locally devised traditional rules guide the community people to manage the VCF sustainably. The vegetation survey showed that the density of Komolchori VCF was 1420 trees/ha with a basal area of 27.98 m2/ha. The Shannon–Weiner index, species diversity index and index of dominance in the study area were 2.91, 0.62, 0.09, respectively. 相似文献
88.
Antibody Prevalence and Risk Factors for Toxoplasma gondii Infection in Women from Multan,Pakistan
下载免费PDF全文
![点击此处可从《Zoonoses and public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. M. Nazir M. Akhtar A. Maqbool A. Waheed M. A. Sajid M. A. Ali M. Oneeb M. A. Alam A. N. Ahmad N. Nazir S. Fatima D. S. Lindsay 《Zoonoses and public health》2017,64(7):537-542
Toxoplasma gondii infections are prevalent in humans and warm‐blooded animals. Maternal infections during pregnancy may have devastating consequences for transplacentally infected neonates. This study was conducted to examine the seroprevalence of antibodies to T. gondii in pregnant women of childbearing age and determine risk factors associated with pregnancy history, pet ownership, social and cultural factors at Nishtar Hospital, Multan. Samples were collected from 403 women and examined using a commercially available enzyme‐linked immunosorbent assay (ELISA). The overall prevalence of antibodies to T. gondii was 17.6% (71) in the 403 samples collected from women. Antibodies to T. gondii were present in 19.4% (45) of 232 pregnant women and 15.2% (26) of the samples from 171 non‐pregnant women. This study identified miscarriage history, pet ownership, type of residence, marital status, source of drinking water and eating habits as significant (P < 0.05) risk factors associated with the presence of antibodies to T. gondii infection. Seroprevalence was not significantly different (P > 0.05) in women from different ethnic groups based upon lifestyle and culture. 相似文献
89.
JABERALANSAR Zahra 《干旱区科学》2017,9(4):489-503
Monitoring of rangeland forage production at specified spatial and temporal scales is necessary for grazing management and also for implementation of rehabilitation projects in rangelands. This study focused on the capability of a generalized regression neural network(GRNN) model combined with GIS techniques to explore the impact of climate change on rangeland forage production. Specifically, a dataset of 115 monitored records of forage production were collected from 16 rangeland sites during the period 1998–2007 in Isfahan Province, Central Iran. Neural network models were designed using the monitored forage production values and available environmental data(including climate and topography data), and the performance of each network model was assessed using the mean estimation error(MEE), model efficiency factor(MEF), and correlation coefficient(r). The best neural network model was then selected and further applied to predict the forage production of rangelands in the future(in 2030 and 2080) under A1 B climate change scenario using Hadley Centre coupled model. The present and future forage production maps were also produced. Rangeland forage production exhibited strong correlations with environmental factors, such as slope, elevation, aspect and annual temperature. The present forage production in the study area varied from 25.6 to 574.1 kg/hm~2. Under climate change scenario, the annual temperature was predicted to increase and the annual precipitation was predicted to decrease. The prediction maps of forage production in the future indicated that the area with low level of forage production(0–100 kg/hm~2) will increase while the areas with moderate, moderately high and high levels of forage production(≥100 kg/hm~2) will decrease both in 2030 and in 2080, which may be attributable to the increasing annual temperature and decreasing annual precipitation. It was predicted that forage production of rangelands will decrease in the next couple of decades, especially in the western and southern parts of Isfahan Province. These changes are more pronounced in elevations between 2200 and 2900 m. Therefore, rangeland managers have to cope with these changes by holistic management approaches through mitigation and human adaptations. 相似文献
90.
Noshin Ilyas Fakhra Ambreen Nazima Batool Muhammad Arshad Roomina Mazhar Fatima Bibi 《Communications in Soil Science and Plant Analysis》2018,49(2):148-158
Crop rotation is a supportive management practice in which legumes greatly improve the growth and yield of subsequent cereal crops, particularly wheat. In this study, effects of mung bean (Vigna radiata)?? on the yield and quality of grains of following wheat crop were determined. An experiment was carried out with two sets of wheat (Triticum aestivum) crops: one grown following mung bean (Vigna radiata) crop and the other grown after a fallow period. Concentrations of macronutrients, sugar, protein, amino acids, and phytohormones of wheat were determined. The grain protein concentration of wheat was improved if cultivated after mung bean, and nitrogen and other macronutrients of wheat were increased significantly. In case of phytohormone contents in the wheat crop, abscisic acid concentration showed no change, but the concentrations of gibberellin increased significantly by 41% and indole acetic acid by 30% as a result of crop rotation. Sugar content in wheat cultivated after mung bean BRM-318 showed 10% increase and wheat protein content increased by 17% and 20%, respectively. The present study demonstrated that crop rotation simulated yield and improved the nutritional value of wheat grain compared to wheat which followed the fallow period. 相似文献