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   330篇
  免费   21篇
林业   13篇
农学   11篇
  24篇
综合类   16篇
农作物   8篇
水产渔业   39篇
畜牧兽医   178篇
园艺   3篇
植物保护   59篇
  2023年   3篇
  2022年   19篇
  2021年   18篇
  2020年   13篇
  2019年   9篇
  2018年   13篇
  2017年   10篇
  2016年   17篇
  2015年   23篇
  2014年   18篇
  2013年   32篇
  2012年   27篇
  2011年   21篇
  2010年   13篇
  2009年   9篇
  2008年   17篇
  2007年   16篇
  2006年   14篇
  2005年   16篇
  2004年   14篇
  2003年   12篇
  2002年   7篇
  2001年   2篇
  2000年   3篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
排序方式: 共有351条查询结果,搜索用时 31 毫秒
251.
252.
The present study involved the isolation and characterization of canine tumor endothelial cells (TECs) from 2 malignancies. TECs were isolated using magnetic cell sorting following FITC labeling with UEA1 lectin, and they were characterized by measuring genetic and histopathological endothelial markers. Isolated TECs exhibited a cobblestone-like morphology and expressed both vascular endothelial growth factor receptor 2 (VEGFR2) and Von Willebrand factor (vWF). Further, both TECs and tumor cells derived from a seminoma exhibited increased C-X-C chemokine receptor type 7 (CXCR7) expression. However, CXCR7 expression was not detected in TECs and tumor cells derived from a hepatocellular carcinoma. Understanding TEC specific traits may be important in the development of more efficacious anti-angiogenic therapies that do not induce adverse effects.  相似文献   
253.
The Flinders Technology Associates filter paper cards (FTA® cards) can be used to store nucleic acid from various samples and are easily portable. However, RNA is physicochemically unstable compared with DNA, and appropriate methods have not been established for storage and extraction of RNA from FTA® cards. The present study investigated the optimum conditions for storage and elution of viral RNA (vRNA) using rabies virus (RABV) applied to FTA® cards. When TE buffer was used, the elution rates of vRNA increased with the length of the elution time. When the cards were stored at −80°C or −20°C, vRNA was stable over 3 months. Degradation of vRNAs occurred following storage at 4°C and room temperature, suggesting that RNA should be extracted from cards as soon as possible if no freezer is available. When we tried to amplify vRNA from RABV-infected animal brains applied to FTA® cards and stored at −80°C for 6 months, we did not detect any amplified products with the primer set for 964 bp of RABV N gene. However, we were able to detect amplified products by increasing the elution time of vRNA from FTA® cards from 30 min to 24 hr or by changing the primer sets to amplify 290 bp of N gene. Thus, we recommend extending the elution time for damaged or low concentration samples in FTA® cards.  相似文献   
254.
Otitis media of the left ear was diagnosed by video otoscopic examination in a 7-year-old, intact male Shih-tzu dog (weight, 5.1 kg), that also had three complex ceruminous adenomas and a Pseudomonas aeruginosa infection in the left ear canal. In such cases, total ear canal ablation is usually required. However, a complete cure was achieved in the present case without total ear canal ablation. The complex ceruminous adenomas were excised using a diode laser, and repeated cleansing of the tympanic cavity and ear canal was implemented using a video otoscope. As a result, the ear canal was closed in a U-form, and the otitis media was cured.  相似文献   
255.
256.
257.
258.
Polyaniline (PANI) and shell membrane composites have been synthesized via chemical oxidative polymerization of aniline in the presence of shell membrane. Combination of surfactant, PANI, and shell membrane allows production of conductive textile with smooth surface. Fourier transform infrared spectroscopy (FTIR) measurements suggest that the oxidation degree of PANI was affected by the initial ratio of shell membrane vs. monomer amount. The PANI/shell membrane composites were characterized with UV-vis absorption spectroscopy, electron spin resonance (ESR) spectroscopy. Electrical conductivity of the composites was measured with four-probe method. The surface of the composites was observed with scanning electron microscopy (SEM). Thermal stability of the composites was discussed with the result of thermogravimetric analysis.  相似文献   
259.
Regulatory elements in the promoter of phenylalanine ammonia-lyase gene 1 of pea (PSPAL1) in response to nonpathogenic attack were identified by in vivo footprinting analysis. The footprints determined AC-rich sequences, Box-I and Box-II, that were conserved at similar positions in the phenylpropanoid gene promoters from several plants. To reveal the functions of the AC-rich sequence in nonpathogen-responsiveness, we constructed Box-I-deletion PSPAL1 promoter (dB-1) with GUS reporter gene and transformed it into tobacco plant. The dB-1 had reduced basal expression and a complete loss of nonpathogen-responsiveness. These results indicate the essentiality of Box-I for PSPAL1 activation induced by nonpathogenic attack. Received 27 October 1999/ Accepted in revised form 25 November 1999  相似文献   
260.
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