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   3831篇
  免费   274篇
  国内免费   5篇
林业   663篇
农学   77篇
基础科学   6篇
  771篇
综合类   277篇
农作物   136篇
水产渔业   228篇
畜牧兽医   1665篇
园艺   81篇
植物保护   206篇
  2023年   26篇
  2022年   28篇
  2021年   45篇
  2020年   70篇
  2019年   48篇
  2018年   146篇
  2017年   139篇
  2016年   165篇
  2015年   95篇
  2014年   133篇
  2013年   258篇
  2012年   261篇
  2011年   248篇
  2010年   131篇
  2009年   116篇
  2008年   204篇
  2007年   226篇
  2006年   208篇
  2005年   187篇
  2004年   182篇
  2003年   169篇
  2002年   160篇
  2001年   104篇
  2000年   96篇
  1999年   59篇
  1998年   27篇
  1997年   35篇
  1996年   22篇
  1995年   62篇
  1994年   19篇
  1993年   19篇
  1992年   21篇
  1991年   11篇
  1990年   21篇
  1989年   17篇
  1988年   25篇
  1987年   10篇
  1986年   15篇
  1985年   15篇
  1984年   16篇
  1983年   16篇
  1982年   9篇
  1980年   21篇
  1979年   9篇
  1978年   14篇
  1977年   8篇
  1976年   9篇
  1975年   8篇
  1973年   8篇
  1970年   10篇
排序方式: 共有4110条查询结果,搜索用时 31 毫秒
81.
New Forests - In seedling-based reforestation operations, seed source is known to be an influential variable affecting outplanting success. Adaptive variation among seed sources may also be an...  相似文献   
82.

In this study, the information needs of non-industrial private forest owners in Finland, after logging operations, were investigated. The study was carried out as an online survey in 2017. The survey was targeted at non-industrial private forest owners who had sold their timber during the previous 10 years (2008–2017) and whose email addresses were in the customer relationship management system of a large wood procurement company in Finland. A response link for the survey was successfully sent to 31,988 forest owners, of whom 3323 replied (response rate: 10.4%). The final study data included 3284 non-industrial private forest owners. The results of the study, which need to be interpreted cautiously due to the low response rate, showed that the forest owners want better-quality reporting after logging operations. Furthermore, the results suggested that gender, age, education, occupational status, place of living, size of, and access to, forest property, and length of, and objectives for, forest ownership have a significant effect on their information needs. Younger, highly-educated, female, urban-living and multi-objective forest owners with larger forest holdings and short forest ownership tenures desired more information. Particularly, the respondents conveyed that they would like more and better information about thinning harvesting result. The results also indicated that when different groups of forest owners call for certain information, there is a need for producing different types of reports after logging operations for different forest owner segments.

  相似文献   
83.
84.
85.
86.
A simple direct method is described to measure the length of fungal hyphae in soil. The accuracy of the method is discussed and comparison is made with other methods recommended for assaying fungal biomass in soil. Some results showing the seasonal fluctuation of mycelial length in soil are presented.  相似文献   
87.
88.
89.
90.
The aim of the study was to describe and evaluate competitiveness of Estonian spice-cured sprat products in Estonia and Thailand. Sample A was saltiest, Sample B had lowest overall spiciness, and Sample C had highest pepper flavor and sour taste intensity. The main drivers of consumer acceptance for the spice-cured sprat products were different: flavor and appearance in Estonia and appearance and odor in Thailand. In Estonia, one cluster of consumers liked the traditional (Sample A) and lightly spiced (Sample B) sprat products, while the other cluster liked the traditional (Sample A) and the marinated (Sample C) sprat products. In Thailand, all samples scored low, but manual clustering indicated that marinated (Sample C) sprat products are most acceptable. The current study showed that spice-cured sprat products in general can be accepted by Thai consumers, especially as part of meals, if further flavor development is carried out with the products.  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