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   200篇
  免费   2篇
林业   8篇
农学   5篇
  23篇
综合类   6篇
农作物   3篇
水产渔业   13篇
畜牧兽医   115篇
园艺   4篇
植物保护   25篇
  2023年   1篇
  2022年   8篇
  2021年   10篇
  2020年   5篇
  2018年   2篇
  2017年   2篇
  2016年   1篇
  2015年   6篇
  2014年   6篇
  2013年   11篇
  2012年   16篇
  2011年   10篇
  2010年   11篇
  2009年   10篇
  2008年   9篇
  2007年   14篇
  2006年   13篇
  2005年   19篇
  2004年   10篇
  2003年   16篇
  2002年   16篇
  2001年   5篇
  1998年   1篇
排序方式: 共有202条查询结果,搜索用时 15 毫秒
101.
An intracranial lipomatous hamartoma was found in the third ventricle of a 7-week-old female BALB/cAnNCrlCrlj mouse. The nodule was composed of mature white adipose cells, which contained one large fat droplet, and there was no evidence of cytological atypia. The brain parenchyma at the retrosplenial granular cortex and the hippocampus in the cerebrum were slightly compressed, and the choroid plexus was dislocated downward. Scattered capillary vessels penetrated the nodule from the surrounding tissue. Based on these findings, the lesion was diagnosed as a lipomatous hamartoma that occurred from the roof of the third ventricle. This extremely rare tumor-like nodule represents an overgrowth of the mature adipocyte population as a malformation rather than a true neoplasm.  相似文献   
102.
In early January 2015–2017, anthracnose was detected on Satsuma mandarin orange (SMO) (Citrus unshiu) fruits kept in farmers’ storage rooms in Saga Prefecture, Japan. Three single-spore isolates from rotten fruits reproduced the postharvest anthracnose symptoms in wound-inoculated SMO fruits and were re-isolated from lesions. The isolates were identified as Colletotrichum fioriniae based on conidial morphology, culture characteristics, rDNA-ITS, and beta-tubulin-2 gene sequences. This is the first report of postharvest anthracnose on SMO caused by C. fioriniae.  相似文献   
103.
104.
Chicken interferon-gamma (ChIFN-gamma) was expressed by baculovirus in a C-terminal truncated form, namely ChIFN-gammaT, to accelerate the secretion of the expressed protein. It is also expressed as ChIFN-gammaT bearing poly His tag, ChIFN-gammaTHis, for easy purification. The expressed proteins were detected by SDS-PAGE analysis with Coomassie brilliant blue staining. The purified ChIFN-gammaTHis with nickel chelated column showed anti-viral activity in vitro and stimulation of the secretion of nitrogen intermediates such as nitric oxide in chicken peripheral blood mononuclear cells. Antiserum against ChIFN-gammaTHis recognized the 15 kDa, 16 kDa, and 32 kDa bands that seemed to be an unglycosylated monomer, a glycosylated monomer, and a homodimer of ChIFN-gammaTHis in the culture supernatant, respectively. The anti-serum also recognized around 14 kDa and 28 kDa bands in the sera of chickens or concanavalin A stimulated spleen cell culture supernatants that seemed to be monomeric and dimeric forms of a natural ChIFN-gamma, respectively.  相似文献   
105.
Detailed measurements of photon flux density (PFD) on the paddy field water surface were conducted under sunny sky conditions using a photosensor array of 100 small photodiodes under rice canopies at the heading and ripening stages. PFD on paddy water surface was not uniform and spatially variable even within a short distance of a few centimeters, showing that the irregular penetration of direct sunlight significantly affects the light environment under the canopies. Although occasional high peaks of PFD were observed, most of the water surface was exposed to a PFD of less than 200 µmol m−2 s−1, even around midday. Mean PFD were high at midday and low in early morning or late evening. Mean ratios of the PFD under the canopy to that outside the canopy (RPFD) were also high at midday and low in early morning or late evening, which can be explained by Poisson's model of light penetration. Maximum mean PFD and mean RPFD were often observed not around noon, but when the azimuth angle of the sun coincided with the row direction. Moreover, under rice canopies at the heading stage, rapid increases and decreases of mean RPFD were observed immediately before and after the peak time. These results indicate that significant high photosynthetic carbon fixation by the paddy field weeds can take place only during the few hours when the azimuth angle of the sun coincides with the row direction.  相似文献   
106.
Glucose delivery and uptake by the mammary gland is a rate‐limiting step in milk synthesis. Insulin resistance is believed to increase throughout the body following the onset of lactation. To study glucose metabolism in peak‐, late‐, and non‐lactating cows we analyzed the expression of an adipokine, namely, adiponectin, decreased insulin resistance, leptin, and a novel insulin‐responsive glucose transporter (GLUT12) in the adipose tissue and mammary gland by using real‐time polymerase chain reaction. Our results demonstrated that the mRNA level of adiponectin in the adipose tissue was greater in non‐lactating cows than in peak‐lactating cows. In the adipose tissue, there were no significant differences in the abundance of GLUT12 mRNA between the peak‐, late‐, and non‐lactating cows. In contrast, in the mammary gland, the mRNA level of GLUT12 was greater in non‐lactating cows than in peak‐ and late‐lactating cows. In the adipose tissue, the mRNA level of leptin and peroxisome proliferator‐activated receptor gamma 2 (PPARγ2) was greater in non‐lactating cows than in peak‐lactating cows. The results of the present study suggest that in lactating cows adiponectin plays an important role in insulin resistance in the adipose tissue; in the mammary gland, GLUT12 expression is believed to be an important factor for insulin‐dependent glucose metabolism.  相似文献   
107.
The composition of the molecular species of triacylglycerols (TG) in subcutaneous fat biopsied from Japanese Black steers was studied during the fattening period. An analysis of the fatty acid (FA) composition of the TG showed that palmitic, palmitoleic, stearic and oleic acids were the major FA, together accounting for over 80% of the total FA. The concentrations of C14:0, C16:0 and C18:0 decreased between 10 and 30 months of age, while those of C16:1 c9 and C18:1 c9 increased during the fattening period. The major molecular species among more than 40 compounds were palmitoyl‐dioleoyl‐glycerol (POO) and dipalmitoyl‐oleoyl‐glycerol (PPO). POO showed the highest concentration during the fattening period. The levels of palmitoyl‐oleoyl‐linoleoyl glycerol and some tentatively identified molecular species increased during the fattening period, while the levels of tripalmitoyl, dipalmitoyl‐stearoyl‐glycerol, palmitoyl‐distearoyl and palmitoyl‐stearoyl‐oleoyl‐glycerol decreased with growth. A comparison of the experimental values of TG molecular species with theoretical values derived from the experimental FA contents showed that the FA distribution in TG was non‐random. TG synthesis favors the formation of TG molecular species containing at least one C16 FA, rather than three C18 FA.  相似文献   
108.
The genetic diversity of the mangrove tree speciesKandelia candel andBruguiera gymnorrhiza in the Southwest Islands of Japan was investigated. These islands are located at the periphery of the distribution area of the two species, and their populations are relatively small. Allozyme analyses of 17 loci inK. candel and 13 loci inB. gynmorrhiza revealed very little genetic variation in both species. At the species level, the proportion of polymorphic loci was 4.2%, the average effective number of alleles per locus was 1.02, and the average expected heterozygosity was 0.012 inK. candel. The corresponding figures forB. gymnorrhiza were 9.0%, 1.06 and 0.035, respectively. However, the coefficients of genetic differentiation among the populations were high (G ST=0.165 forK. candel and 0.253 forB. gymnorrhiza). The genetic variation and habitat area ofK. candel on Amami Island is greater than on the islands Okinawa and Iriomote. The genetic variation and habitat area ofB. gymnorrhiza is greater on Iriomote Island than on the islands Okinawa and Amami. The level of genetic variation in both of the species might be related to their population sizes.  相似文献   
109.
Screening and isolation of angiotensin I-converting enzyme (ACE) inhibitors from Japanese cedar (Cryptomeria japonica) based on the in vitro ACE inhibitory assay were attempted. The ethanol extract from outer bark showed the highest inhibitory activity (IC50 is 16g/ml) among 24 extracts prepared from roots, leaves, heartwood, sapwood, inner bark, and outer bark by successive extraction with four solvents. The fractionation of the outer bark ethanol extract followed by the bioassay resulted in the isolation of two strong ACE inhibitors, catechin and dimeric procyanidin B3. The bioassay of three flavan-3-ols including (+)-catechin and six flavones revealed that most of these compounds have high ACE inhibitory activity. The results suggest that the phenolic hydroxyl group at the C7 position and heterocyclic oxygen atom of these compounds are important for expressing the inhibitory activity.  相似文献   
110.
Soil respiration and soil carbon dioxide (CO2) concentration were investigated in a tropical monsoon forest in northern Thailand, from 1998 to 2000. Soil respiration was relatively high during the rainy season and low during the dry season, although interannual fluctuations were large. Soil moisture was widely different between the dry and wet seasons, while soil temperature changed little throughout the year. As a result, the rate of soil respiration is determined predominantly by soil moisture, not by soil temperature. The roughly estimated annual soil respiration rate was 2560gCm–2year–1. The soil CO2 concentration also increased in the rainy season and decreased in the dry season, and showed clearer seasonality than soil respiration did.  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