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   416篇
  免费   14篇
  国内免费   1篇
林业   25篇
农学   4篇
基础科学   1篇
  119篇
综合类   18篇
农作物   36篇
水产渔业   15篇
畜牧兽医   183篇
园艺   11篇
植物保护   19篇
  2024年   1篇
  2023年   4篇
  2022年   8篇
  2021年   17篇
  2020年   12篇
  2019年   28篇
  2018年   18篇
  2017年   12篇
  2016年   17篇
  2015年   13篇
  2014年   17篇
  2013年   24篇
  2012年   32篇
  2011年   35篇
  2010年   16篇
  2009年   14篇
  2008年   31篇
  2007年   24篇
  2006年   23篇
  2005年   20篇
  2004年   26篇
  2003年   16篇
  2002年   15篇
  2001年   1篇
  1999年   1篇
  1996年   1篇
  1993年   2篇
  1991年   1篇
  1988年   1篇
  1984年   1篇
排序方式: 共有431条查询结果,搜索用时 617 毫秒
171.
To ascertain the potential transmission of influenza A viruses to dogs and cats, a serological survey was carried out in North‐eastern Italy. In a 4‐year period, 637 serum samples were screened using a Mab‐based competitive ELISA for anti‐nucleoprotein A (NPA) antibody detection of influenza viruses. No evidence of anti‐NPA antibodies was observed.  相似文献   
172.
Virgin olive oil is valued for its flavor, but unacceptable off-flavors may develop on storage in food products containing this oil due to oxidation. The oxidative stability of oil-in-water emulsions containing bovine serum albumin (BSA) and virgin olive oil phenolic compounds was studied. Four oil-in-water emulsions with and without BSA and phenols isolated from virgin olive oil were prepared. These model systems were stored at 60 degrees C to speed up lipid oxidation. Primary and secondary oxidation products were monitored every three days. Peroxide values and conjugated diene contents were determined as measures of the primary oxidation products. p-Anisidine values and volatile compounds were determined as measures of the secondary oxidation products. This latter determination was carried out by headspace solid-phase microextraction coupled with gas chromatography. Although olive oil phenolic compounds and BSA contributed some antioxidant activity when present as individual additives, the combination of BSA with phenols in an emulsion showed 58-127% synergy, depending on which analytical method was used in the calculation. The emulsion containing phenolic compounds and BSA showed a low level of deterioration after 45 days of storage at 60 degrees C.  相似文献   
173.
174.
A medico-ethnobotanical study was conducted among the Tabarkin communities living in Calasetta and Carloforte, in south-western Sardinia. These communities represent a Ligurian minority who have resided in Sardinia since their forebears migrated from Tabarka in Tunisia in the second half of the 18th Century, having previously migrated to Tabarka from Genoa in 1544. In this study, we conducted more than 200 interviews and recorded 53 botanical taxa and 72 folk pharmaceutical preparations, which represent the folk medicine of the Tabarkins. The folk phytotherapy of the Tabarkins living in Calasetta and Carloforte is quite restricted compared with other folk phytotherapy recorded in similar recent ethnobotanical studies conducted in Sardinia. This could indicate that there has been a remarkable erosion of Traditional Knowledge (TK) within these two communities. Of particular interest are a few local medical uses we recorded that have never or only very rarely been documented in Italy; namely the use of Dittrichia graveolens (L.) Greuter as an anti-haemorrhoidal, of Centaurea calcitrapa L. as a remedy for malaria, of Glycyrrhiza glabra L. in ophthalmic treatments, and of Urtica dioica L. as an antiviral in cases of German measles. Most of the botanical species quoted in this research are referred to in the two centres using a local Ligurian idiom. Most of the medico-botanical uses we recorded are very similar to those collected in other ethnobotanical surveys carried out in Liguria and south-western Sardinia. Because there was no evidence in this research of any substantial ethnobotanical traces related to the communities’ North-African experience, it would appear that the Tabarkins have readily adopted their host culture’s use of medicinal plants and have retained their own traditional cognitive concepts and knowledge of the natural plant world through the language only.  相似文献   
175.
The present work evaluated the development of different Curcuma longa L. explants (leaves basis, root tips and ancillary buds from rhizome) stimulated by exogenous polyamines, combined with naphtalen-acetic acid (NAA) or with 6-benzyl-aminopurine (BAP), to produce callus and its subsequent differentiation. The explants, isolated from field plants, were previously subjected to a basic cleaning method and were inoculated onto Murashige and Skoog culture medium (MS) [Murashige, T.S., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiologia Plantarum 15, 473–497] supplemented with NAA (2.0 mg L−1). Buds were subjected to different treatments, with or without 5.0 and 10.0 mmol L−1 exogenous polyamines (mixture of putrescine:spermine:spermidine, 1:1:1) combined with NAA. The calluses obtained were transferred into the same medium, supplemented with the mixture of polyamines combined with BAP, in order to induce plant differentiation. For C. longa, buds were the most efficient explants for callus induction (p < 0.05). The application of exogenous polyamines (5.0 and 10.0 mmol L−1) produced the most developed callus, with numerous roots. The medium supplemented with 10 mmol L−1 polyamine mixture, combined with BAP, induced good regeneration, producing vigorous plants and excellent shoot formation.Polyamines addition promoted the formation of callus, roots and leaves, representing an important factor in the determination of indirect organogenesis in C. longa L., and putrescine content may be considered a valuable marker of the differentiation process in this specie, as well as the enzyme peroxidase.  相似文献   
176.
Toxocara canis (T. canis) is originally a parasite of canine bitches and their pups. The pathogenicity of T. canis infection is enhanced during pregnancy and puppyhood. The aim of this study was to investigate if modification of IFNgamma and IL-10 secretion occurs during infection in pregnant dogs and puppies. Analysis of cytokines secreted could let us hypothesize a role for IL-10 and/or IFNgamma in T. canis infection. We tested T. canis-specific production of IFNgamma and IL-10 by lymphocytes of pregnant dogs and their puppies after in vitro re-exposure to purified excretory/secretory antigen (ESAg) from T. canis. Blood mononuclear cells (BMC) isolated from pregnant dogs and their puppies were cultured in the presence of ESAg. Cultures' supernatants were tested for cytokine levels by ELISA. Results obtained showed that IL-10 concentrations increased during pregnancy in infected animals and in the meantime IFNgamma production decreased. In puppyhood, we observed that, IL-10 concentration decreased with the age of puppies mainly in infected animals while IFNgamma increased. In conclusion, our data suggests that BMC of infected dogs have a particular modification of IL-10 and IFNgamma synthesis. These data could be the basis to design immunotherapeutic approaches.  相似文献   
177.
A 9-year-old neutered male domestic shorthair cat was presented because of coughing, dysphagia, and prostration. Examination revealed firm bilateral anterocervical swellings extensively adhered to the surrounding tissues. Anisocoria with left-side miosis was also evident. X-ray and ultrasound examinations along with a fine-needle aspiration biopsy were performed. Slides were stained with May-Grünwald Giemsa, and a diagnosis of salivary gland carcinoma was made. At surgery, the tumor was found to involve both submandibular salivary glands as well as adjacent lymph nodes and surrounding tissues. The cat was euthanized and necropsy was performed. The majority of tissues and organs examined histologically, including mandibular and retropharyngeal lymph nodes, soft palate, laryngopharynx and lungs, contained neoplastic cells whose appearance was consistent with adenocarcinoma. Bilateral salivary adenocarcinoma has not previously been reported in cats, and extensive metastases are rare.  相似文献   
178.
The present work aims to investigate if the variation of each parameter in Longissimus lumborum muscle could correspond to the same or to a similar variation of the parameter in the other muscles. The work presents results of Pearson's correlations between Longissimus lumborum samples and other muscle samples, such as Biceps femoris, Rectus femoris, Semimembranosus, Supraspinatus and Semitendinosus in horse meat. A total of 27 male IHDH (Italian Heavy Draught Horse) breed foals were employed. They were slaughtered at 11 months of age and the above‐mentioned muscles were sampled. The Longissimus lumborum muscle showed to be representative of other muscles and of the whole carcass for some chemical parameters (moisture, protein and ash) and for some fatty acids profile patterns such as C12:0, C14:0, total monounsaturated fatty acid and polyunsaturated fatty acid, but poor correlations were recorded for intramuscular fat concentration, rheological and colorimetric parameters. Although almost all the qualitative parameters in meat are affected by the anatomical site and by the muscle, the Longissimus lumborum is often not representative in horse meat with regard to modifications of this parameters.  相似文献   
179.

Objective

To evaluate whether subcutaneous (SC) metoclopramide (0.2 mg kg?1) administered 30 minutes prior to (T30) or simultaneously with (T0) intramuscular (IM) morphine (0.2 mg kg?1) and dexmedetomidine (0.003 mg kg?1) reduces the incidence of nausea and emesis in healthy dogs.

Study design

Prospective, randomized and blinded study.

Animals

A total of 45 dogs scheduled for elective procedures.

Methods

Dogs were assigned randomly to three groups to be administered SC metoclopramide (0.2 mg kg?1) 30 minutes before (group M30) or simultaneously (group M0) to IM morphine (0.2 mg kg?1) and dexmedetomidine (0.003 mg kg?1). Dogs in the control group (group C) were administered SC saline at T30 and T0. Dogs were observed for 30 minutes after premedication to evaluate signs of nausea (continuous lip-licking and sialorrhoea) and emesis. Signs of pain or discomfort caused by SC injections were also recorded.

Results

There were no statistical differences amongst groups for age, body weight and sex. More dogs developed continuous lip-licking in group C (12/15, 80.0%) compared to dogs in group M30 (1/15, 6.7%) and dogs in group M0 (5/15, 33.3%; p = 0.0001 and p = 0.01, respectively). More dogs developed sialorrhoea in group M0 (8/15, 53.3%) and in group C (10/15, 66.7%) compared to dogs in group M30 (2/15, 13.3%; p = 0.03 and p = 0.004, respectively). More dogs vomited in group M0 (4/15, 26.7%) and in group C (9/15, 60.0%) compared to dogs in group M30 (0/15, 0.0%; p = 0.05 and p = 0.0003, respectively). None of the dogs demonstrated signs of pain or discomfort during SC metoclopramide injection.

Conclusions and clinical relevance:

Subcutaneous metoclopramide at 0.2 mg kg?1 may reduce IM morphine and dexmedetomidine-induced nausea and emesis if administered 30 minutes in advance. It is effective in reducing lip-licking even when administered concurrently with IM morphine–dexmedetomidine.  相似文献   
180.
Anitschkow cells (AC) are a peculiar type of stromal cells observed in myocardium, cardiac valves and coronary vessels wall whose origin, characterization and role remain controversial. In human heart, they represent a histological hallmark of Aschoff nodules in rheumatic fever, but they have also been observed in other myocardial pathologies. Firstly, they have been considered a myocyte‐derived cells, but light microscopy, immunohistochemical and ultrastructural studies pointed out that a macrophagic/histiocytic origin cannot be excluded. Many authors also reported extracardiac AC or an Anitschkow nuclear pattern, thus suggesting that these cells may represent a chromatin pattern rather than a specific cell type. In veterinary medicine, AC were described in myocarditis, myocardial necrosis, degenerative and inflammatory endocardial diseases of several species. Recently, AC have been observed in intramural coronary arteries of different animals (including cattle and fish) affected by arteriosclerotic processes. Stress related to the intensive livestock farming could represent a mechanotransduction promoting factor of arteriosclerotic changes allowing the development of Anitschkow chromatin pattern. Further studies both in human and veterinary medicine are needed to confirm the origin and role of these peculiar cells.  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