首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   389篇
  免费   17篇
林业   32篇
农学   15篇
基础科学   1篇
  105篇
综合类   18篇
农作物   23篇
水产渔业   40篇
畜牧兽医   142篇
园艺   13篇
植物保护   17篇
  2023年   2篇
  2022年   10篇
  2021年   17篇
  2020年   19篇
  2019年   21篇
  2018年   9篇
  2017年   13篇
  2016年   13篇
  2015年   13篇
  2014年   17篇
  2013年   23篇
  2012年   35篇
  2011年   31篇
  2010年   24篇
  2009年   18篇
  2008年   25篇
  2007年   21篇
  2006年   18篇
  2005年   12篇
  2004年   13篇
  2003年   14篇
  2002年   12篇
  2001年   3篇
  2000年   4篇
  1999年   4篇
  1998年   3篇
  1996年   2篇
  1994年   1篇
  1992年   1篇
  1986年   1篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
排序方式: 共有406条查询结果,搜索用时 31 毫秒
81.
A common seagull (Larus fuscus) was found near the southern coast of Italy by the veterinarians of the local wild animal rescue center. Physical examination of the bird revealed an ulcerated mass involving a majority of the oral cavity; the mass did not allow for normal feeding. After the bird died necropsy was performed and the mass was histologically and immunohistochemically examined. The morphology and the immunoreactivity for Melan-A and S-100 antigens led to a diagnosis of malignant melanoma. This is the first case of malignant melanoma described in a seagull, and herein we compare the characteristics of the present case with malignant melanoma already described in domestic animals.  相似文献   
82.
The ovicidal effect of the nematophagous fungus Pochonia chlamydosporia on eggs of Ascaris suum was tested under laboratory conditions. A. suum eggs were plated on 2% water–agar with seven fungal isolates (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) and control without fungus. After 5, 7, 10, 14, 15 and 21 days of incubation, approximately 100 eggs were removed from the plates and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo showing hyphal penetration and internal egg colonization. The isolates effectively destroyed A. suum eggs and all types of effects were observed during the experiment. There was no variation in ovicidal capacity (type 3 effect) among the isolates (p > 0.05) throughout the experiment. After 21 days, isolate 5 showed the highest percentages of type 3 effect (58.33%). The results indicated that P. chlamydosporia (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) can destroy A. suum eggs and is, therefore, a potential biological control agent of nematodes.  相似文献   
83.
In this study, an experimental challenge was carried out by feeding Nero Siciliano pigs with acorn to evoke melanin-like pigmentation and support the hypothesis that it is caused by ingested material. Twelve pigs were studied, 6 fed with acorns and 6 fed commercial feed. At slaughter, all the animals fed on acorns showed black discolouration of almost all lymph nodes. The lymph nodes were normal in size and shape. Histochemical tests performed on tissues allowed us to identify and differentiate the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Our data, and the well-known steps of melanin formation, confirm that swine enzymes could act on phenolic substances found in acorns.  相似文献   
84.
85.
86.
The Valdostana is a local dual purpose cattle breed developed in Italy. Three populations are recognized within this breed, based on coat colour, production level, morphology and temperament: Valdostana Red Pied (VPR), Valdostana Black Pied (VPN) and Valdostana Chestnut (VCA). Here, we investigated putative genomic regions under selection among these three populations using the Bovine 50K SNP array by combining three different statistical methods based either on allele frequencies (FST) or extended haplotype homozygosity (iHS and Rsb). In total, 8, 5 and 8 chromosomes harbouring 13, 13 and 16 genomic regions potentially under selection were identified by at least two approaches in VPR, VPN and VCA, respectively. Most of these candidate regions were population-specific but we found one common genomic region spanning 2.38 Mb on BTA06 which either overlaps or is located close to runs of homozygosity islands detected in the three populations. This region included inter alia two well-known genes: KDR, a well-established coat colour gene, and CLOCK, which plays a central role in positive regulation of inflammatory response and in the regulation of the mammalian circadian rhythm. The other candidate regions identified harboured genes associated mainly with milk and meat traits as well as genes involved in immune response/inflammation or associated with behavioural traits. This last category of genes was mainly identified in VCA, which is selected for fighting ability. Overall, our results provide, for the first time, a glimpse into regions of the genome targeted by selection in Valdostana cattle. Finally, this study illustrates the relevance of using multiple complementary approaches to identify genomic regions putatively under selection in livestock.  相似文献   
87.
Abstract

Composting olive oil pomace could solve the problem of disposal, by recycling this organic waste for agricultural purposes. Furthermore, application of composted organic waste could be a way to sustain both soil fertility and production, especially in organic farming. Therefore, the aim of this research was to evaluate the phytotoxicity and the effects of application of olive pomace composts on emmer performance and soil properties. Two types of olive pomace composts, with a different initial C/N ratio, were stopped at the active phase and processed until maturation. The obtained four olive pomace composts were compared with a commercial fertilizer in a two-year field experiment. Before the field trial, a bioassay was performed to assess phytotoxicity both for the raw pomace and the not-stabilized composts. Growing and yielding data for emmer were determined during the two-year period and soil characteristics were measured at the start and at the end of the experiment.

The composts were not phytotoxic (germination index was higher than 90%) and their total organic carbon content was always higher than the minimum values established by the Italian fertilizers legislation. The emmer protein content was significantly higher in the matured compost treatment with low C/N, than in the other compost treatments. Its value was comparable with that of the commercial fertilizer, suggesting a good performance on crop yield quality. Although not significant, this compost showed an increase of 9.8% in grain yield compared with commercial fertilizer treatment. On the whole, it can be suggested that repeated compost application might preserve the soil organic carbon content and supply macronutrients to a crop.  相似文献   
88.
The use of grains alternative to wheat or rye is a challenging task for cereal technologists, and currently new technologies are under investigation as tools to improve the performances of these alternative grains. In this work the effects of high Hydrostatic Pressure (HP) on oat batters were investigated. Oat batters were treated for 10 min at 200, 300, 350, 400 or 500 MPa. Scanning electron microscopy and bright field microscopy showed that high HP significantly affected oat batter microstructure, and both starch and proteins were affected. Treatment at high HP significantly improved batter viscosity and elasticity. At pressures ≤300 MPa the increase in the viscous component was higher than the increase in the elastic component. On the contrary, at pressures ≥350 MPa the elastic component was predominant. Differential scanning calorimetry revealed that high HP induced starch gelatinisation, which started at 300 MPa and was almost complete after treatment at 500 MPa. High HP also affected water- and salt-soluble as well as urea-soluble oat proteins. Analysis of proteins soluble in different buffers revealed that pressures ≥300 MPa induced the formation of urea-insoluble complexes and/or disulfide bonds. Overall, the extent of starch gelatinisation and protein modification was dependent on the applied pressure, but the results collected so far clearly show that high HP can be used to improve the functionality of oat batters.  相似文献   
89.
Gluten is a fundamental component for the overall quality and structure of breads. The replacement of the gluten network in the development of gluten-free cereal products is a challenging task for the cereal technologist. The functionality of proteins from gluten-free flours could be modified in order to improve their baking characteristics by promoting protein networks. Transglutaminase (TGase) has been successfully used in food systems to promote protein cross-linking. In this study, TGase was investigated for network forming potential on flours from six different gluten-free cereals (brown rice, buckwheat, corn, oat, sorghum and teff) used in breadmaking. TGase was added at 0, 1 or 10 U/g of proteins present in the recipe. The effect of TGase on batters and breads was evaluated by fundamental rheological tests, Texture Profile Analysis and standard baking tests. Three-dimensional elaborations of Confocal Laser Scanning Microscopy (CLSM) images were performed on both batters and breads to evaluate the influence of TGase on microstructure. Fundamental rheological tests showed a significant increase in the pseudoplastic behaviour of buckwheat and brown rice batters when 10 U of TGase were used. The resulting buckwheat and brown rice breads showed improved baking characteristics as well as overall macroscopic appearance. Three-dimensional CLSM image elaborations confirmed the formation of protein complexes by TGase action. On the other side, TGase showed negative effects on corn flour as its application was detrimental for the elastic properties of the batters. Nevertheless, the resulting breads showed significant improvements in terms of increased specific volume and decreased crumb hardness and chewiness. Under the conditions of this study, no effects of TGase could be observed on breads from oat, sorghum or teff. Overall, the results of this study show that TGase can be successfully applied to gluten-free flours to improve their breadmaking potentials by promoting network formation. However, the protein source is a key element determining the impact of the enzyme.  相似文献   
90.
Thirteen landraces of cowpea (Vigna unguiculata (L.) Walp. subsp. unguiculata cv. gr. Unguiculata) have been morphologically and agronomically characterised as part of a plan for safeguarding and protecting plant biodiversity typical of Lake Trasimeno (Umbria, central Italy). Sixty plants per accession were scored for plant vigour, growth habit, flower colour, days to flowering, days to first mature pod, pod length, total number of pods produced, seed colour pattern, 100 seed weight, total seed yield and virus susceptibility. With the exception of vigour and growth habit, all landraces appeared to be well differentiated from one another for all the characters considered. Strategies and problems related to their in situ conservation are discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号