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   11381篇
  免费   830篇
林业   1173篇
农学   424篇
基础科学   42篇
  2613篇
综合类   736篇
农作物   483篇
水产渔业   760篇
畜牧兽医   4607篇
园艺   284篇
植物保护   1089篇
  2023年   102篇
  2022年   129篇
  2021年   231篇
  2020年   228篇
  2019年   152篇
  2018年   558篇
  2017年   525篇
  2016年   469篇
  2015年   380篇
  2014年   431篇
  2013年   653篇
  2012年   918篇
  2011年   819篇
  2010年   451篇
  2009年   347篇
  2008年   711篇
  2007年   663篇
  2006年   534篇
  2005年   559篇
  2004年   513篇
  2003年   468篇
  2002年   383篇
  2001年   275篇
  2000年   241篇
  1999年   218篇
  1998年   69篇
  1997年   55篇
  1996年   42篇
  1995年   63篇
  1994年   37篇
  1993年   34篇
  1992年   78篇
  1991年   67篇
  1990年   62篇
  1989年   55篇
  1988年   53篇
  1987年   47篇
  1986年   47篇
  1985年   48篇
  1984年   44篇
  1983年   35篇
  1979年   36篇
  1974年   26篇
  1973年   21篇
  1972年   22篇
  1971年   24篇
  1970年   27篇
  1969年   25篇
  1968年   25篇
  1967年   20篇
排序方式: 共有10000条查询结果,搜索用时 126 毫秒
61.
Pepper huasteco yellow vein virus (PHYVV) is the main virus of pepper crop in Mexico. No resistant cultivars are available and resistance breeding is hampered by the lack of knowledge of heritability (h 2) of PHYVV resistance. This is a continuation of previous studies and the objectives were to analyze the h 2 and the behavior of the resistant trait to PHYVV. Four resistant assays were done with three resistant wild lines (UAS12, UAS13 and UAS10) of Capsicum annuum in the S4, S5, S6 and S7 generation under greenhouse conditions. Plants from all tests were inoculated with PHYVV through Bemisia tabaci. Line UAS12 was the most resistant showing a significantly proportion of resistant plants, less disease symptoms and longer incubation time, followed by the lines UAS13 and UAS10 in all assays. Distribution of symptoms showed a bimodal tendency in all the trials, suggesting that two groups of genes are involved in this resistance trait. The lines UAS12, UAS13 and UAS10 showed the same pattern of response to selection with an average of h 2 of 0.17, 0.06, 0.02 and 0.00 in the S4, S5, S6 and S7, respectively. These results indicate that all lines responded positively to the selection in the S4, S5 and S6, whereas in the S7 there was no response by the possible exhaustion of variation. Line UAS12 is the most promising genotype and the lines UAS13 and UAS10 are genetic resources that can be supplemented to breed the resistance of PHYVV. These results provides basic information for resistance breeding.  相似文献   
62.
63.
64.
Journal of Crop Science and Biotechnology - Coffee (Coffea Arabica L.) is threatened by biotic and abiotic stresses. Nevertheless, the breeding of Arabica coffee is restricted due to its low...  相似文献   
65.
We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non‐pyrogenic organic carbon in a furnace at 375 °C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC determination only in calcareous soils. Decarbonation changes the thermal properties of organic matter, creating more recalcitrant carbon than in the initial sample. Higher CaCO3 and organic carbon content results in a more pronounced artefact. The reversal of the first two steps of the chemo‐thermal oxidation method (i.e. thermal oxidation before soil decarbonation) eliminates this artefact. Overall, our results suggest that BC content may have been overestimated in a large number of studies on calcareous soils.  相似文献   
66.
67.
68.
69.
Plant Foods for Human Nutrition - In this study the breadmaking potential of lupin flour from L. mutabilis after being debittered (DLF) and solid state fermented (FLF) was evaluated in lupin-wheat...  相似文献   
70.
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