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   100篇
  免费   1篇
林业   7篇
农学   4篇
基础科学   2篇
  34篇
综合类   4篇
农作物   3篇
水产渔业   9篇
畜牧兽医   30篇
园艺   5篇
植物保护   3篇
  2022年   1篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2016年   3篇
  2015年   2篇
  2014年   4篇
  2013年   19篇
  2012年   9篇
  2011年   8篇
  2010年   7篇
  2009年   5篇
  2008年   6篇
  2007年   2篇
  2006年   8篇
  2005年   1篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1976年   1篇
排序方式: 共有101条查询结果,搜索用时 15 毫秒
61.
62.
Fusarin C is a Fusarium mycotoxin that rearranges under reversed phase chromatographic conditions. In this study, the rearrangement of fusarin C was examined in detail, and the formation of fusarins under different conditions was optimized. All relevant fusarins including (10Z)-, (8Z)-, and (6Z)-fusarin C were isolated and identified by NMR. To confirm the involvement of the 2-pyrrolidone ring in the rearrangement of fusarin C, 15-methoxy-fusarin C was synthesized. For the first time, the structure of open-chain fusarin C was elucidated, and on the basis of these data, the rearrangement product of fusarin C was identified as epi-fusarin C. The results were confirmed by detailed NMR measurements and density functional theory calculations. Furthermore, a new fusarin C like metabolite, which was named dihydrofusarin C, was detected by analysis of the crude extract of fusarin C with high-performance liquid chromatography coupled to UV and Fourier transform mass spectrometry.  相似文献   
63.
Two cultivars of lettuce plants (Lactuca sativa L. cvs Berlo and Kirsten) were grown for two months in late fall in NFT under three different nitrogen (N)‐regimes but with the same total N concentration (13.4 mM). A reference treatment with a nutrient solution containing 94% nitrate (NO3) and 6% ammonium (NH4) was compared with urea and proteinate treatments in which 20% of the NO3 of the reference treatment was replaced by either of these two N sources. Proteinate is a fertilizer produced in Turkey containing 8% amino acid N and 8% NO3‐N. For both cultivars the fresh weights of the harvested plants were unaffected by the N source as was also the total N uptake. Nitrate content, however, was considerably lower in the urea and proteinate plants, values for the three treatments ranging from 3314 to 4579 mg NO3/kg fresh wt making up from between 44.3% to 55.4% of the total plant N. Of the two cultivars, Berlo accumulated greater concentrations of NO3 than did Kirsten. The accumulation of chloride (Cl) was in the reverse order of that of NO3 with greatest concentrations occurring in the proteinate plants.  相似文献   
64.
The light and scanning electron microscopic structure of the filiform lingual papillae was studied in five adult porcupine (three males and two females). The tongue was characterised by a round tip, a rostral median sulcus and a deep lingual fossa which was situated just rostral to a prominent inter-molar eminence corresponding to a torus linguae. The filiform papillae were curved, enclosed a large connective tissue core and were separated by wide inter-papillary zones covered by a thick epithelium. Most filiform papillae had a cylindrical shape, but the rostral and central parts of the tongue contained a number of flat, comb-shaped papillae with rounded tips.  相似文献   
65.
Crop loads and leaf fertilizers are highly important for yield and quality of grapevine. This research was conducted in the Konya province of Turkey in 2008 and 2009. The effects of crop loads and leaf fertilizers were investigated on yield and quality of Vitis vinifera L. cv. ‘Gök üzüm’. The combined leaf fertilizer (TAR??-ZF) significantly increased quality parameters such as berry length, berry weight, maturity index, juice yield and drying index of grapevine. Increasing crop load values (16, 21, and 26 buds/vine) increased fresh grape yield and juice yield; however, maturity index and drying index decreased in comparison to the control. According to these results, it was suggested that to produce a high yield 26 buds/vine pruning and non-fertilization could be utilized or to increase quality parameters 16 buds/vine pruning, and fertilization may be applied on grapevine cultivation.  相似文献   
66.
Growth performance, carcass characteristics, post-slaughtering and haematological parameters of Kivircik and Karacabey Merino male lambs in conventional and organic management systems were compared. The animals which were weaned at 7 weeks of age were divided into Kivircik conventional, Kivircik organic (KO), Karacabey Merino conventional and Karacabey Merino organic (MO) groups containing 12 lambs each. Fattening was ended when lambs attained 35 kg of live weight. The time to attain the determined fattening weight was significantly different among the groups, and Merino lambs having higher live weight gain were earlier than Kivircik lambs (p?相似文献   
67.
Black Scorpion fish (Scorpaena porcus Linnaeus 1758) caught during monthly sampling carried out in 2003 in the Dardanelles, Turkey, were examined for the parasite. Trachelobdella lubrica. Infested fish were caught only during December 2003, and the clinical conditions of the 12 fish naturally infested with T. lubrica included fin rot, swollen foci of skin and haemorrhages of the gill and abdominal skin. The prevalence, intensity and abundance of infestation in December 2003 were 40%, 1.75 and 0.70, respectively. The average hepatosomatic index of the infested fish was lower than that of noninfested fish, while the means of the kidney index, splenosomatic index, condition factor, body weight and length were not significantly different between the infested and noninfested fish groups. Blood analysis was conducted on 12 naturally infested and 12 healthy (noninfested) Black Scorpion fish to determine the possible characteristic changes in blood parameters of the fish in response to natural infestation with T. lubrica. Blood leucocyte counts, haematocrit levels, serum total protein, albumin phosphorus, urea, glucose, globulin, cholesterol and triglyceride concentrations in naturally infested Black Scorpion fish were significantly less than those of the noninfested fish (p < 0.05). No significant decreases were observed in the serum sodium, iron, calcium, potassium, chlorine, blood urea nitrogen and creatinine values of the naturally infested fish. Blood haemoglobin values, erythrocyte counts and serum glutamate aspartate aminotransferase (glutamate oxalacetate transaminase), alanine aminotransferase (glutamate pyruvate transaminase), uric acid and very low-density lipids levels of infested fish were insignificantly greater than those in healthy fish.  相似文献   
68.
This comprehensive overview of block copolymer micelle nanolithography (BCMN) will discuss the synthesis of inorganic nanoparticle arrays by means of micellar diblock copolymer approach and the resulting experimental control of individual structural parameters of the nanopattern, e.g., particle density and particle size. Furthermore, the authors will present a combinational approach of BCMN with conventional fabrication methods, namely, photolithography and electron beam lithography, which combines the advantages of high-resolution micronanopatterning with fast sample processing rates. In addition, the authors will demonstrate how these nanoparticle assemblies can be transferred to polymer substrates with a wide range of elasticity. In the second part of this report the authors will introduce some of the most intriguing applications of BCMN in biology and materials science: The authors will demonstrate how nanoparticle arrays may be used as anchor points to pattern functional proteins with single molecule resolution for studying cellular adhesion and present a technological roadmap to high-performance nanomaterials by highlighting recent applications for biomimetic optics and nanowires.  相似文献   
69.
This experiment was conducted to evaluate the effects of chromium (chromium picolinate, Cr Pic) and vitamin C (L-ascorbic acid) supplementation on egg production and egg quality in laying hens (Hy-Line) kept at 18 degrees C (at thermo-neutral zone) or 6 degrees C (cold stress) in temperature-controlled rooms. One hundred and fifty laying hens (32 week-old) were divided into 5 groups, 30 hens per group. The laying hens kept at 6 degrees C temperature were fed either a basal diet (low temperature-basal diet, LTB group) or the basal diet supplemented with either 400 micrograms of Cr per kg diet (Cr group), 250 mg of L-ascorbic acid per kg diet (Vit C group) or 400 micrograms of Cr plus 250 mg of L-ascorbic acid per kg diet (Vit C + Cr group) while hens kept at 18 degrees C fed a basal diet (thermo-neutral-basal diet, TNB group). Performance and egg quality were significantly reduced in LTB group compared with TNB group. Supplemental chromium and vitamin C significantly increased live weight change, egg production, and improved feed efficiency in cold-stressed hens compared with group fed the basal diet at 6 degrees C brought up to the values of the group reared under thermoneutral conditions (18 degrees C). Egg production and egg weight were also greater in each supplemental group compared with the LTB group. Separately or as a combination, supplemental chromium and vitamin C increased serum insulin but decreased corticosterone, glucose and cholesterol concentrations. Results of the present study show that supplementing vitamin C and chromium, particularly as a combination, improved the performance of cold-stressed hens. Such a combination of supplement can offer a potential protective management practice in preventing cold stress-related losses in performance of laying hens.  相似文献   
70.
In order to simulate soil suction and soil temperature, a field study was carried out in the experimental farm of the Agricultural Faculty, University of Cukurova (Adana/TURKEY), for a period of two years. During this period the soil was bare. Data collected regularly include soil suction and soil temperature. Meteorological data were obtained from the Adana Climatological Station. Data on soil suction and soil temperature were used to calibrate the simulation model, proposed by Huwe and van der Ploeg (1988). It was found that the model, after having been calibrated, performed quite well. A fair agreement between measured and simulated soil temperatures was obtained. However, the calculated and measured soil suction values were found to be considerably different. The simulation model used in this study appears to be applicable for the conditions of the Cukurova Region in Southern Turkey.  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