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   243篇
  免费   7篇
  国内免费   3篇
林业   33篇
农学   7篇
  50篇
综合类   6篇
农作物   8篇
水产渔业   40篇
畜牧兽医   79篇
园艺   2篇
植物保护   28篇
  2022年   2篇
  2021年   3篇
  2020年   1篇
  2019年   3篇
  2018年   4篇
  2017年   6篇
  2016年   6篇
  2015年   6篇
  2014年   7篇
  2013年   28篇
  2012年   8篇
  2011年   21篇
  2010年   9篇
  2009年   9篇
  2008年   17篇
  2007年   16篇
  2006年   18篇
  2005年   12篇
  2004年   14篇
  2003年   16篇
  2002年   13篇
  2001年   11篇
  2000年   5篇
  1999年   1篇
  1998年   2篇
  1997年   4篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1985年   1篇
  1979年   1篇
  1978年   1篇
  1963年   1篇
排序方式: 共有253条查询结果,搜索用时 15 毫秒
241.
Two Japanese Black bull calves from a dam showed muscular weakness and became recumbent after birth. At necropsy, skeletal muscles, including face, neck, body and proximal and distal forelimb and hindlimb were extremely pale in color and edematous. Histopathological examination of skeletal muscles revealed degenerative changes as follows: replacement of muscle with fat, variation in muscle fiber diameter, internal nuclei, central core-like structures, and vacuolar and hyaline degeneration of muscle fibers. Ultrastructurally, the lesions were characterized by focal myofibrillar disorganization with streaming or irregularity of Z bands. The present cases seem to be classified as congenital myopathy based on pathological alterations and age of onset.  相似文献   
242.
An efficient system for growingin vitro plantlets ofEucalyptus citriodora Hook was developed. In the conventional closed system of culture with 2% sugar-containing gellan gum Murashige and Skoog (MS) medium supplemented with 0.02 mg/l indole-3-isobutyric acid, a serious defoliation of shoots was observed after three weeks. In contrast, plantlets grown on the sugar-free MS medium in the aerated bottle under 3,000 ppm CO2 enriched condition did not show any defoliation. A marked enhanced growth of plantlets and no defoliation were observed on rockwool with the sugar-free liquid MS medium in the “Culture Pack”, made of fluorocarbon polymer film, under CO2 enriched condition. CO2 enrichment for this sugar-free “Culture Pack”-Rockwool system was also found to contribute to an improved growth of the plants in acclimatization. A part of this paper was presented at the 106th Annual Meeting of the Japanese Forestry Society (1995).  相似文献   
243.
ABSTRACT:   Volatile compounds formed by photosensitized oxidation and autoxidation of cod liver oil were compared. A 5-mL portion of oil-in-water emulsion (10% oil, 1% Tween 20 and 0.1 mM of rose bengal or 0.1 mM of ferrous chloride) was sealed into a 50-mL crimp top vial. The vial with added rose bengal was exposed to a 100-watt tungsten bulb (6000 lux) in an oven at 40°C, while the vial with added ferrous chloride was wrapped in aluminum foil to shield light and kept in the same oven. Volatiles in the headspace of the vials were collected by solid phase microextraction technique and analyzed with a gas chromatography-flame ionization detector and a gas chromatography – mass spectrometry. Approximately 51 kinds of volatiles were identified from oxidation of cod liver oil. All the volatiles identified in the sample with added rose bengal were identified in the sample with added ferrous chloride, however, tremendous differences of their relative ratios were found, which probably is useful to explain the flavor differences between sun-dried seafood and mechanical-dried seafood. The formation mechanisms of certain volatiles were proposed.  相似文献   
244.
Lactating Holstein-Friesian cows kept in tie-stall barn were used as subjects in this study. Rectal examination, ultrasonography and blood sampling were conducted every other day and then daily after the day on which diameter of the corpus luteum decreased. After the luteal diameter decreased for 2 consecutive days, rectal and ultrasound examinations, blood sampling, and observation of estrous signs were conducted at 6-h intervals. Most of the estrous signs became obvious with the increase in estradiol-17β (E2) and became most remarkable 24 to 30 hours before ovulation, at which point the E2 peak and luteinizing hormone (LH) surge were achieved, and then weakened which progression to ovulation. The correlation between the intensity of four estrous signs (hyperemia and swelling of the intravaginal part of the uterus, opening of the external uterine orifice and viscosity of the cervical mucus) and the plasma E2 concentration was higher than that of three estrous signs (swelling of the vulva, contraction of the uterus, diameter of uterine horn) and the plasma E2 concentration. The relaxation of the intravaginal part of the uterus showed a unique change compared with the other estrous signs, and it became most obvious 6, 12 and 18 h before ovulation; this obviously relaxed period was consistent with the generally accepted theoretical optimal time for artificial insemination (AI), i.e., 6 to 24 h after initiation of estrus. These results suggest that observation of estrous signs by vaginoscopic examination gave useful information for detection of the optimal timing of AI in the periovulatory period in lactating dairy cows kept in a tie-stall barn.  相似文献   
245.
We investigated the proteome of a female Crested Ibis (Nipponia nippon, ID#162) that died on March 10, 2010 at the Sado Japanese Crested Ibis Conservation Center. Protein preparations from the brain, trachea, liver, heart, lung, proventriculus, muscular stomach, small intestine, duodenum, ovary and neck muscle were subjected to in‐solution shotgun mass spectrometry (MS)/MS analyses using an LTQ Orbitrap XL mass spectrometer. A search of the National Center for Biotechnology Information Gallus gallus databases revealed 4253 GI (GenInfo Identifier) numbers with the sum of the same 11 tissues examined in the Crested Ibis. To interpret the obtained proteomics data, it was verified in detail with the data obtained from the brain of the Crested Ibis. It has been reported that drebrin A is specifically expressed in adult chicken brain. In the shotgun proteomic analyses of the Crested Ibis, we identified drebrin A as a brain‐specific protein. Furthermore, Western blotting analysis of the protein preparations from 10 tissues of the Crested Ibis and 150‐day‐old hens using anti‐drebrin antibodies showed intensive expression of approximately 110 kDa polypeptides of drebrin in both brains. We believe firmly that the present data will contribute to initial and fundamental steps toward understanding the Crested Ibis proteome.  相似文献   
246.
Toshiaki Yamada 《Euphytica》1989,43(1-2):53-57
Summary GA-insensitive Rht genes of 18 Japanese modern varieties and landraces were identified. Out of 12 modern varieties tested 6 carried only Rht1, and the other 6 carried only Rht2. No varieties carried both Rht1 and Rht2 or Rht3. The geographical distribution of the Rht genotypes in the Japanese modern varieties was clearly localized. All 6 landraces tested carried only Rht2.  相似文献   
247.
Cytoplasmic male sterile (CMS) plants were obtained by asymmetrical protoplast fusion between red cabbage (fertile) and normal radish (fertile). The CMS plants showed restriction fragment length polymorphism (RFLP) patterns of mitochondrial (mt) DNA that were different from those of both parental lines. PCR analysis of mtDNA of the CMS plants and though Southern blot analysis showed that the mtDNA of the CMS line had the characteristics of the ogura CMS type. The results suggested that the orf138 gene and the ogura type atp6 gene are present in normal fertile cabbage and radish at a low copy level. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
248.
Severe rotting and blight of seedlings of soybean, Glycine max (L.) Merr., were found in Hiroshima Prefecture in the southwest region of Japan in July 2009. A filamentous microorganism, isolated repeatedly from the diseased seedlings and identified as Pythium myriotylum, was demonstrated to be pathogenic to seedlings of soybean. The disease was new in Japan, and we propose to include this oomycete as one of the pathogens causing damping-off of soybean.  相似文献   
249.
A single radial immunodiffusion (SRID) assay and a chemiluminescent immunoassay (CLIA) were initially developed for alpha-fetoprotein (AFP) of the striped dolphin. Utilizing these developed assays, we investigated pregnancy-associated changes in the levels of AFP in the sera of fetuses and pregnant females of three dolphin species; samples were either collected from captive individuals or obtained as fishery by-products. The concentrations of AFP in the fetal serum ranged from 419.0 to 2026.3 μg/ml in the striped dolphin, 12.6 to 1218.7 μg/ml (for an AFP equivalent; eqAFP) in the common bottlenose dolphin and 770.6 to 3129.1 μg eqAFP/ml in the Risso''s dolphin. AFP levels decreased with increased fetal size in fetuses over 20 cm in length. The concentrations of AFP in sera of pregnant females ranged from 7.18 to 8068.7 ng/ml in the striped dolphin, 6.6 to 1241.1 ng eqAFP/ml in the common bottlenose dolphin and 3.4 to 2868.7 ng eqAFP/ml in the Risso''s dolphin. The levels in most pregnant females were equal to or lower than those found in males and nonpregnant individuals, although a few pregnant females exhibited extremely high levels (in the range of hundreds to thousands of nanograms per milliliter). Such high levels of AFP were not observed during pseudopregnancy. To our knowledge, this is the first report on basal profiles for serum AFP levels in small odontocetes. The profiles indicated that AFP may play a significant role during embryonic development, although maternal levels do not appear to be a diagnostic biomarker for monitoring pregnancy.  相似文献   
250.
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