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   101篇
  免费   6篇
林业   7篇
农学   3篇
  12篇
综合类   5篇
农作物   7篇
水产渔业   9篇
畜牧兽医   58篇
园艺   1篇
植物保护   5篇
  2023年   1篇
  2022年   3篇
  2021年   12篇
  2020年   2篇
  2019年   4篇
  2018年   6篇
  2017年   4篇
  2016年   4篇
  2015年   3篇
  2014年   7篇
  2013年   10篇
  2012年   4篇
  2011年   6篇
  2010年   2篇
  2009年   3篇
  2008年   8篇
  2007年   5篇
  2006年   6篇
  2005年   4篇
  2004年   1篇
  2003年   6篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1996年   1篇
  1984年   1篇
排序方式: 共有107条查询结果,搜索用时 139 毫秒
71.
Paddy and Water Environment - A low-cost subsurface irrigation system with ring-shaped emitters has been applied and considered as a way to improve water irrigation efficiency in a region where...  相似文献   
72.
73.
Journal of General Plant Pathology - Mosaic, chlorosis, brown spots, or roughness were found on Vigna marina and V. riukiuensis, which are salt-resistant wild relatives of cowpea (V. unguiculata)...  相似文献   
74.

Coriandrum sativum L. (coriander), which is an annual herb of the Apiaceae family, has been traditionally used as a remedy. Here we tested whether heated extract of coriander leaf protects nigral dopaminergic neurodegeneration after exposure to 6-hydroxydopamine (6-OHDA). After injection of 6-OHDA into the rat substantia nigra pars compacta (SNpc), dopaminergic degeneration, which was determined by tyrosine hydroxylase immunostaining, was rescued by co-injection of CaEDTA, an extracellular Zn2+ chelator, suggesting that extracellular Zn2+ influx is involved in neurodegeneration. Both intracellular Zn2+ dysregulation determined by ZnAF-2 fluorescence and dopaminergic degeneration in the SNpc induced by 6-OHDA were rescued by co-injection of 0.25% coriander extract, which also reduced reactive oxygen species (ROS) production in the SNpc determined by aminophenyl fluorescein fluorescence. The present study suggests that coriander leaf extract protects nigral dopaminergic neurodegeneration induced by intracellular Zn2+ dysregulation. It is likely that the nutraceutical property of coriander leaf extract contributes to the protection via reducing ROS production.

  相似文献   
75.
Plant Foods for Human Nutrition - The immunomodulating effect of phlorotannin was investigated in mice stimulated by ovalbumin. When analyzing the main components of phlorotannin concentrate (PTC)...  相似文献   
76.
An 8-year-and-1-month-old female blue tegu (Salvator merianae) was brought to a clinician with severe cough. The patient died 11 days later despite supportive care, and necropsy was performed by a clinician. The lumen of the distal trachea was almost completely occluded by a milk-white, hard mass measuring 1 cm in diameter. Histopathologically, the mass comprised spindle-shaped to polygonal cells arranged in a loose sheet with abundant production of basophilic cartilaginous matrix, consistent with chondrosarcoma. Reports of tracheal neoplasms in reptiles are limited, and to the best of our knowledge this represents the first pathological documentation of tracheal chondrosarcoma in a reptile.  相似文献   
77.
A synthetic method for obtaining lignin oligomer that contains only the β-O-4 structure is described in detail. This method consists of three reaction steps: (1) the synthesis of t-butoxycarbonylmethyl vanillin (2), (2) the nucleophilic addition oligomerization of compound 2, and (3) the reduction of the oligomeric β-hydroxyl ester. In the first step, compound 2 was synthesized from vanillin in 96.8% yield. In the second step, compound 2 was oligomerized with commercial lithium diisopropylamide (LDA) to obtain oligomeric β-hydroxyl ester (3) in 87.2% yield; the repeating units of this oligomer were joined only by β-O-4 linkages as confirmed by nuclear magnetic resonance (NMR) spectroscopy. In the third step, the oligomeric β-hydroxyl ester (3) was reduced with LiAlH4 to give compound 4 in 42.4% yield. On the basis of NMR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and gel permeation chromatography analyses of compound 4, it was concluded that compound 4 was an oligomeric lignin model compound containing only β-O-4 interunit linkages. The number average degree of polymerization (DPn) of obtained compound 4 was about 7.0 (M w/M n = 1.42). Using this oligomeric lignin model compound, conventional degradation and analytical methods will give new information.  相似文献   
78.
There has been an increase in the number of Jack Russell Terriers (JRTs) diagnosed with adenomas and adenocarcinomas of the gastrointestinal tract in Japan. This study retrospectively investigated the clinical and histopathological features and prognosis of adenocarcinomas arising in the gastrointestinal tract in JRT dogs. Seven JRTs and 39 dogs of other breeds diagnosed with gastrointestinal adenocarcinoma were included in the study. The most common sites of gastrointestinal adenocarcinoma in JRTs were the pylorus and rectum. On histopathological examination, these adenocarcinomas showed a papillary or tubular growth pattern, and the lesions were confined within the mucosal epithelium and poorly invasive. Among all dogs with gastric adenocarcinoma, the median survival time (MST) for five of the JRTs could not be determined because more than half of the cases remained alive, while the MST for nine non-JRT dogs was 34 days. Among all dogs with adenocarcinoma in the large intestine, the MST for three of the JRTs could not be determined, while the MST for nine non-JRT dogs was 1,973 days. The difference in MST between JRT and non-JRT dogs with gastric adenocarcinoma was significant (P=0.0220). Since gastrointestinal adenocarcinomas in JRTs show distinct characteristics with respect to their clinical features, treatment course, and prognosis, a different surgical and medical treatment plan should be considered compared to the management of gastrointestinal adenocarcinomas in other dog breeds.  相似文献   
79.
Determination of 3 neonicotinoid insecticides, nitenpyram, imidacloprid, and acetamiprid, was studied. Vegetables and fruits were extracted with acetonitrile. The crude extract was passed through a weak anion-exchange cartridge (PSA). The effluent was subjected to silica gel cartridge. Imidacloprid and acetamiprid were eluted with 10 mL of 4:6 (v/v) acetone/hexane, followed by nitenpyram with acetone (20 mL). Pesticides were determined by HPLC with a C-18 column and diode-array detection system. Imidacloprid and acetamiprid were recovered at about 90% at the spike levels with 0.2 and 2 mg/kg in cucumber, potato, tomato, eggplant, Japanese radish, and grape. Nitenpyram was recovered at 64-80%. Relative standard deviations were less than 10% throughout all the recovery tests. In the residue analysis, agriculturally incurred pesticides at 0.08-0.14 mg/kg were designated with UV spectra compared with respective reference standards.  相似文献   
80.
This study evaluates the influence of temperature manipulation on circulating levels of sex steroids and gonadal maturation in F1 generation Senegalese sole Solea senegalensis breeders kept under either continuous light (LL) or natural photoperiod (NP). Under LL, progressive water temperature reduction during early winter [treatment MT (modified temperature)] significantly elevated [compared with exposure to LL and constant temperature (CT)] plasma steroid levels in females (January–February) and males (January) and proportion of females initiating maturation (January), suggesting a modulatory role of decreasing temperature in the early phases of sole gonadal recrudescence. Under NP, treatment MT did not stimulate female gonadal maturation despite the significantly higher plasma testosterone levels (February) compared with exposure to NP and CT, which may indicate that females at early‐intermediate phases of ovarian development, the predominant stages of maturation at early winter, were less responsive to the treatment. Conversely, treatment MT significantly enhanced male androgen production from January onwards, together with an increase in proportions of running individuals (March), indicating that males were also responsive to this treatment at mid‐late phases of testicular development. Our data further support the strong influence of water temperature on the overall control of gonadal maturation in Senegalese sole.  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