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   211篇
  免费   16篇
林业   27篇
农学   7篇
  50篇
综合类   20篇
农作物   19篇
水产渔业   23篇
畜牧兽医   31篇
园艺   3篇
植物保护   47篇
  2023年   4篇
  2022年   4篇
  2021年   6篇
  2020年   7篇
  2019年   3篇
  2018年   13篇
  2017年   17篇
  2016年   10篇
  2015年   13篇
  2014年   13篇
  2013年   15篇
  2012年   8篇
  2011年   19篇
  2010年   12篇
  2009年   10篇
  2008年   14篇
  2007年   11篇
  2006年   3篇
  2005年   7篇
  2004年   8篇
  2003年   3篇
  2002年   6篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1995年   1篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1980年   1篇
  1979年   3篇
  1976年   1篇
  1970年   1篇
  1969年   3篇
  1963年   1篇
排序方式: 共有227条查询结果,搜索用时 0 毫秒
71.
72.
A new method for mass percentage determination of fructose and glucose based on FT-Raman spectroscopy is evaluated with a standard HPLC-based method. FT-Raman spectra manipulation is done via the spectrometer software, and a PLS (partial least squares) method is developed with the TQ Analyst software (Ver 1. 1a). The simultaneous quantitative determination uses an input range from 1700 to 700 cm(-1) without correction or baseline factors. The standards used in the PLS method are honey samples previously analyzed by HPLC to obtain their mass percentage concentrations in fructose and glucose. The returned results are statistically tested with those of the HPLC method. Both methods appear to score equally in terms of reproducibility. The honey content of the two sugars in total was found up to 40-74%. The honey samples content in fructose and glucose was determined by HPLC (24.1-42.9% and 16.2-33.1%, respectively) and FT-Raman (24.0-40.8% and 21.1-32.2%, respectively).  相似文献   
73.
74.
Good knowledge of the spatial distribution of fish is critical to stock assessment and successful fisheries management. Depth is often the main gradient along which faunal changes occur when analyzing shelf and upper slope assemblages, and thus knowledge of the bathymetric distribution of fish species is of great importance. The depth distribution of 16 fish species (Chelidonichthys lucernus, Helicolenus dactylopterus, Hoplostethus mediterraneus, Lepidorhombus boscii, Lophius budegassa, Merlangius merlangus, Merluccius merluccius, Micromesistius poutassou, Mullus barbatus, Mullus surmuletus, Pagellus erythrinus, Peristedion cataphractum, Phycis blennoides, Serranus cabrilla, Trigla lyra, and Trisopterus minutus) of the Aegean and the Ionian Seas was evaluated by analyzing experimental bottom trawl data, using generalized additive modeling (GAM) techniques. A variety of bathymetric distribution patterns was observed. The main bathymetric zone of each species was defined based on the modeled relative density. Specifically, the lower and upper limits of the main bathymetric zone of each species were defined as the depths where the estimated relative density of the species becomes less than 1% of the maximum. This definition is proposed as a better and more informative alternative than reporting the minimum and maximum depths of encounter.  相似文献   
75.
The dot enzyme-linked immunosorbent assay (Dot-ELISA), standard ELISA and the complement fixation (CF) tests were compared in the serodiagnosis of African visceral leishmaniasis (kala-azar). Assay sensitivity was determined using sera from 44 patients with parasitologically confirmed kala-azar. Using the Dot-ELISA, 42 of 44 patients (95%) were positive at a reciprocal titer of greater than or equal to 32 (titer range 512-524 288). In the standard ELISA technique, 43 of 44 patients (98%) were positive (titer range 32-32 768). At a reciprocal titer of greater than or equal to 8 in the CF test, 35 patients (80%) were positive, 1 (2%) was negative and 8 patients (18%) showed anticomplementary (AC) activity (titer range 8-2048). Specificity, determined using 33 sera from healthy individuals not living in endemic areas, was 97% in both the Dot-ELISA and the standard ELISA (32 of 33 sera); in he CF test, all sera were negative except 1 (3%) which showed AC activity. Sera from patients with Chagas' disease cross-reacted in the dot-ELISA up to a titer of 512. In the standard ELISA, cross-reactions occurred mainly using sera from patients with Chagas' disease, malaria and syphilis, and to a lesser extent with sera from amebiasis, schistosomiasis and trichinosis patients. Overall titer agreement in replicate experiments was highest in the Dot-ELISA (89%), followed by the standard ELISA (80%) and the CF test (72%).  相似文献   
76.
77.
78.
The objective of this special issue is to highlight the current state of research in the field of insects as food and feed, but also other aspects on the exploitation of insect farming. In this editorial, we make a short introduction of the topic of the special issue, briefly present the contributions that are collected in it and offer some thoughts on the future research priorities and challenges that should be addressed. Regarding insect farming, there are additional applications, such as fertilizer, health-promoting products, and cosmetics, that can be produced and utilized, that go far beyond food and feed production.  相似文献   
79.
Cotton (Gossypium hirsutum L.) is often grown on calcareous soils where manganese (Mn) deficiency is quite common. Despite the fact that Mn deficiency can limit cotton productivity the effect of foliar application of Mn was not determined. A field study was conducted to determine if foliar Mn applications during anthesis affects the growth and yield of cotton. Manganese increased the chlorophyll content by up to 17% compared with the control treatment with no difference between the two rates of Mn. Moreover, Mn increased the seed yield by an average of 30%, the number of bolls per plant by 31%, the number of bolls per square meter by 31% and boll retention by 37% compared with the control, but it did not affect the mean boll weight and the quality of the fibers. Foliar application of Mn increased seed germination by an average of 14% and increased seed vigor (AA) by an average of 28% compared with the control treatment. The results obtained here suggest that foliar Mn application can improve the lint and seed yield and also the seed quality of cotton grown for seed production on calcareous soils.  相似文献   
80.
This study was designed to evaluate the metabolic response to Corinthian raisins in healthy and in patients with type 2 diabetes mellitus. Healthy subjects (n?=?15) and diabetic patients (n?=?15) received 74 g raisins or 50 g glucose as reference food. Blood samples were collected at time 0 (before the consumption) and 30, 60, 90, 120, 150 and 180 min after raisin or glucose consumption. There was no significant difference in baseline glucose and insulin between raisins and reference in both groups. The difference at glucose peaks between raisins and reference was significant in healthy and in diabetics. Glycemic and insulinemic responses were decreased after raisin consumption compared to reference. An estimate of the glycemic index would be 66.3?±?3.4.  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