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   262篇
  免费   22篇
林业   20篇
农学   9篇
基础科学   1篇
  22篇
综合类   20篇
农作物   7篇
水产渔业   52篇
畜牧兽医   134篇
植物保护   19篇
  2021年   4篇
  2020年   5篇
  2019年   3篇
  2018年   3篇
  2017年   8篇
  2016年   12篇
  2015年   10篇
  2014年   7篇
  2013年   16篇
  2012年   21篇
  2011年   20篇
  2010年   8篇
  2009年   7篇
  2008年   19篇
  2007年   17篇
  2006年   13篇
  2005年   15篇
  2004年   14篇
  2003年   9篇
  2002年   7篇
  2001年   17篇
  2000年   12篇
  1999年   3篇
  1998年   2篇
  1996年   3篇
  1995年   1篇
  1992年   4篇
  1991年   3篇
  1990年   4篇
  1989年   5篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   4篇
  1981年   2篇
  1972年   1篇
排序方式: 共有284条查询结果,搜索用时 15 毫秒
21.
We examined the biochemical and structural properties of oryzacystatin-II, a phytocystatin in rice (Oryza sativa L. japonica), under heat-stress conditions. The enzyme inhibitory reactivity of oryzacystatin-II was enhanced by heating in a temperature-dependent manner and reached a maximum level by heating at 65 degrees C for 10 min. Size-exclusion chromatography showed that oryzacystatin-II forms a homodimer at ambient temperature and that the enhancement of inhibitory reactivity is due to the conversion of the dimeric to a monomeric form. The monomeric form of oryzacystatin-II reverted to the dimer during storage at 4 degrees C, suggesting that dimerization is an intrinsic property of oryzacystatin-II. The affinity of the monomer for cysteine proteinases was significantly higher than that of the dimer. This is the first paper to describe the noncovalent dimerization for a cystatin under nonstress conditions.  相似文献   
22.
Nucleotides from yeast RNA were evaluated for their ability to enhance the non-specific immune responses in carp, Cyprinus carpio . Oral administration of nucleotides to fish daily for 3 days resulted in enhanced responses of phagocytic and nitroblue tetrazolium (NBT) activities in kidney phagocytic cells. This activation of kidney cells was observed for at least 10 days post-treatment. The serum complement and lysozyme activities also increased in fish treated with nucleotides. Furthermore, the number of Aeromonas hydrophila in nucleotide-treated fish significantly decreased in the blood, kidney and liver after intraperitoneal injection. Thus yeast nucleotides appear to enhance non-specific immune responses in fish.  相似文献   
23.
To investigate genes involved in intramuscular adipogenesis in ruminants, 16 genes with dramatic variable expression were selected. These were selected from the differentiation‐ and proliferation‐phase libraries of our previous serial analysis of gene expression (SAGE) studies of a clonal bovine intramuscular preadipocyte (BIP) cell line. We harvested the BIP cells over 12 days after adipogenic stimulation with all‐trans retinoic acid (ATRA). Quantitative real‐time PCR confirmed the earlier SAGE study results of the expression patterns of 15 of the genes. On day 6, TG accumulation increased significantly in the BIP cells but was completely inhibited in the 3T3‐L1 cells (the monogastric reference). ATRA enhanced expression levels of six genes whereas it suppressed expression of eight genes on day 3 of adipogenesis in the BIP cells. Forty‐eight hours after transfection, the messenger RNA expression level of the adipose differentiation‐related protein (ADFP), encoded by one of the upregulated genes, in the ADFP small interference RNA (siRNA)‐transfected cells was 3.5% of that in negative control‐transfected cells. Also, 6 days after induction the TG level in the ADFP siRNA‐transfected cells was 21.8% lower than that in negative control‐transfected cells. This analysis of gene expression profiles after ATRA treatment will contribute to our understanding of the molecular mechanisms involved in bovine intramuscular adipogenesis.  相似文献   
24.
ABSTRACT: Genetic polymorphism in kingfish, collected from coastal waters of Japan, Australia and New Zealand, were examined using microsatellite (MS) DNA and mitochondrial DNA (mtDNA) control region markers. Sixteen to 25.7 alleles per locus were observed in three MS markers, while the average observed (and expected) heterozygosities were 0.782 (0.918), 0.750 (0.809) and 0.650 (0.888) for Australian, Japanese and New Zealand kingfish, respectively. Twelve mtDNA haplotypes were detected by the digestion of control region sequences with five endonucleases: Hae III, Hinf I Mbo I, Rsa I and Taq I. Significant genetic divergence was observed between the kingfish population from Japan and those from Australia–New Zealand. There was no significant differentiation among the Australian and New Zealand population samples.  相似文献   
25.
To improve the propagation of Japanese cedar (Cryptomeria japonica D. Don), we investigated the effects of apical and basal temperatures during a water soaking treatment on the adventitious root formation of 70-mm long shoot tip cuttings which have an apical bud. The basal portion of the cuttings was soaked for 28 days in water with temperatures ranging from 10 to 35 °C, at an air temperature of 5 or 10 °C. Control cuttings were soaked in water at 25 °C, with an air temperature of 25 °C. Treated cuttings were then planted in vermiculite rooting medium and grown at an air temperature of 25 °C for 35 days. Adventitious roots initiated earlier and developed more in the cuttings treated with apical temperatures of 5 or 10 °C and basal temperatures of 20–30 °C than in the control cuttings. The rooting percentage was greatest (93 %) in the cuttings treated with a 10/25 °C apical/basal temperature, whereas few control cuttings rooted (13 %). This suggests that the temperature gradient created by warming the basal portion of the cuttings while cooling their apical end stimulates adventitious root formation. When we tested seasonal variation of rootability at 10/25 °C, the rooting percentage increased from early autumn to winter, and decreased from winter to summer. The soluble sugar contents did not directly affect the formation of adventitious roots in the present study.  相似文献   
26.
A critical function of tumor suppressor p53 is the induction of apoptosis in cells exposed to noxious stresses. We report a previously unidentified pro-apoptotic gene, Noxa. Expression of Noxa induction in primary mouse cells exposed to x-ray irradiation was dependent on p53. Noxa encodes a Bcl-2 homology 3 (BH3)-only member of the Bcl-2 family of proteins; this member contains the BH3 region but not other BH domains. When ectopically expressed, Noxa underwent BH3 motif-dependent localization to mitochondria and interacted with anti-apoptotic Bcl-2 family members, resulting in the activation of caspase-9. We also demonstrate that blocking the endogenous Noxa induction results in the suppression of apoptosis. Noxa may thus represent a mediator of p53-dependent apoptosis.  相似文献   
27.
28.
To develop cleaved amplified polymorphic sequence (CAPS) markers for cultivar identification of the tea leaf, 5 primer pairs designed on the basis of genes that encode proteins related to nitrogen assimilation and 26 primer pairs based on expressed sequence tag (EST) sequences of the root of tea plant were screened. From combinations of primer pair and restriction enzyme that showed polymorphism among tea plants, 16 markers were selected and applied to DNA fingerprinting of Japanese tea cultivars. Sixty-three cultivars, except for a bud sport (Kiraka) and its original cultivar (Yabukita) and a pair that was the progeny of the same crossing parent (Harumoegi and Sakimidori), were distinguished from one another. By combining the 16 markers with previously developed CAPS markers and observing the physical appearance, 67 cultivars were distinguishable. The cultivars involve approximately 95% of total tea cultivating area in Japan; therefore, about 95% of tea leaves produced in Japan can be authenticated by labeling their cultivars.  相似文献   
29.
The antibody response of rabbit to infectious bovine rhinotracheitis (IBR) virus was examined. Two rabbits were inoculated with IBR virus strain Los Angeles into the trachea and intravenously, and intravenously two times, respectively. The patterns of antibody titers in the rabbits measured by neutralization test and ELISA were similar to those in the case of bovine. The antibody was detected after the inoculation, and much more antibody was detected after the second inoculation. The fact suggests that rabbits are a very useful laboratory animal for IBR virus infection studies.  相似文献   
30.
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