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排序方式: 共有2055条查询结果,搜索用时 62 毫秒
991.
用新型SPA(Staphylococcal Protein A)协同凝集试验对88份猪血清进行了乙型脑炎病毒(JEV)抗体检测,并与酶联免疫吸附试验(ELISA)进行了对比,两种方法检测结果为:ELISA检测阳性率为62.5%(55/88),SPA阳性率为68.18%(60/88),二者阳性符合率为90.0%(54/60),总符合率为86.3%(76/88).对8份SPF猪血清进行检测,两种方法检测结果均为阴性.结果表明,SPA与ELISA检测乙型脑炎结果符合,前者更为简便和实用. 相似文献
992.
新型职业农民培育是实现乡村振兴战略的重要支撑。2012—2020年间新型职业农民培育研究主要集中在概念界定、内涵与特征、培育模式、面临的问题、绩效评价、未来工作优化建议六个方面。当前研究对新型职业农民培训关注较多,对培育制度关注不够;所构建的绩效考核模型较多,对如何实现培育工作绩效治理关注不够;实证研究也多从个体性视角展开,缺乏整体性分析。建议进一步加大研究力度,并重点关注培育体系中的"政策扶持"环节,以加快我国新型职业农民培育进程。 相似文献
993.
检索获取了中国期刊网收录的1980-2009年间土壤研究文献,提取了其中研究样品的有机质含量信息并形成数据库,统计评价了我国农田表土有机碳含量变化情况。结果表明:1985年以前文献土壤样品有机碳含量平均为(12.88±7.86)g·kg^-1,1985—1992年则为(11.26±6.30)g·kg^-1,1993-2002年为(11.67±5.11)g·kg^-1,而2003-2009年为(11.72±7.15)g·kg^-1;显示,1985年以来农田表土有机碳含量呈现总体上升趋势,支持了我们对土壤监测资料的分析结果。土地利用方式显著影响土壤样品的有机碳含量水平,水田总是高于旱地(P〈0.05),不随时间变化而改变;旱地土壤样品的有机碳含量以1985年前为最高,而水田样品2003-2009年期间含量高于1985年前水平。同时分析表明,旱地农田表土有机碳含量区域差异明显,近30年来,旱地农田表土有机碳含量在华北、华东、西北增加显著(P〈0.05);而在东北显著降低(P〈0.05);华南、西南有机碳含量变化不明显(P〉0.05)。这些结果支持了已有的土壤监测资料和调查资料研究中中国土壤固碳趋势及其地理区域分异的认识。 相似文献
994.
笔者从探析日语"和"一词的词意来源开始,进而阐述了日本"和"一词所体现出的传统文化内涵;揭示了在日本"大和精神"的影响之下,日本民族所不同于其他民族的特征;同时也提出了借鉴日本的"和精神",认识和探讨中国提倡"和谐社会"理念的重要性。 相似文献
995.
在日语教学中实行素质教育,就是要面向全体学生,注重提高学生全面的发展能力;同时要发掘学生学习日语的潜力,减轻学生学习压力,提高课堂效率。 相似文献
996.
Masako Seki Makiko Chono Hitoshi Matsunaka Masaya Fujita Shunsuke Oda Katashi Kubo Chikako Kiribuchi-Otobe Hisayo Kojima Hidetaka Nishida Kenji Kato 《Breeding Science》2011,61(4):405-412
The genotypes of photoperiod response genes Ppd-B1 and Ppd-D1 in Japanese wheat cultivars were determined by a PCR-based method, and heading times were compared among genotypes. Most of the Japanese wheat cultivars, except those from the Hokkaido region, carried the photoperiod-insensitive allele Ppd-D1a, and heading was accelerated 10.3 days compared with the Ppd-D1b genotype. Early cultivars with Ppd-D1a may have been selected to avoid damage from preharvest rain. In the Hokkaido region, Ppd-D1a frequency was lower and heading date was late regardless of Ppd-D1 genotype, suggesting another genetic mechanism for late heading in Hokkaido cultivars. In this study, only 11 cultivars proved to carry Ppd-B1a, and all of them carried another photoperiod-insensitive allele, Ppd-D1a. The Ppd-B1a/Ppd-D1a genotype headed 6.7 days earlier than the Ppd-B1b/Ppd-D1a genotype, indicating a significant effect of Ppd-B1a in the genetic background with Ppd-D1a. Early-maturity breeding in Japan is believed to be accelerated by the introduction of the Ppd-B1a allele into medium-heading cultivars carrying Ppd-D1a. Pedigree analysis showed that Ppd-B1a in three extra-early commercial cultivars was inherited from ‘Shiroboro 21’ by early-heading Chugoku lines bred at the Chugoku Agriculture Experimental Station. 相似文献
997.
Predicting the potential distribution of invasive plants within a specific region is pivotal to planning effective management but is challenged by attempting to model expanding populations that are rarely at equilibrium with their environment. We adopt an ensemble modelling approach to assess the potential distribution of Japanese honeysuckle (Lonicera japonica), a vine invasive to forests of the Cumberland Plateau and Mountain Region in the southeast of USA. The influence of disturbance, spatial and temporal heterogeneity and other landscape characteristics were assessed by creating regional level models based on occurrence records from the United States Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) database. Logistic regression and maximum entropy (MaxEnt) models were assessed independently and evaluated as predictive tools to test the value of presence/absence and presence only data in predicting species distributions. Ensemble models were also developed that combined the predictions of the two modelling approaches to obtain a more robust prediction. While logistic and MaxEnt models were similar in their predictive ability and dominant input variables, the ensemble approach derived the best fitting model overall. The regional distribution of Japanese honeysuckle was influenced greatly by environmental conditions such as elevation, slope, and temperature with anthropogenic activity having significant, though lesser, influence. The ensemble models predict that Japanese honeysuckle has nearly reached its potential distribution. However, given the critical role of minimum temperature on Japanese honeysuckle distribution, future occupancy at higher elevations is likely to increase since January temperatures for this region are predicted to rise by 1-4 °C over the next 100 years. The models also give some indication of the likely effect of land cover change on its distribution. Japanese honeysuckle tended to be associated with a high component of farming or low component of forest within the local neighbourhood. This suggests disturbed forest and/or high fragmentation has a higher invasion potential and given past trends and expected continued population growth this disturbance and fragmentation will only increase. The models can be integrated into forest management decision support systems and assist in the development of long term management plans, integrating the impact of potential climate and land cover change scenarios. 相似文献
998.
Spatial variability of throughfall under a single tree: Experimental study of rainfall amount, raindrops, and kinetic energy 总被引:2,自引:0,他引:2
Kazuki Nanko Yuichi OndaAkane Ito Hiromu Moriwaki 《Agricultural and Forest Meteorology》2011,151(9):1173-1182
To evaluate the spatial variability of throughfall amount, raindrops, and erosivity under a single canopy during calm meteorological conditions, indoor experiments were conducted using a 9.8-m-tall transplanted Japanese cypress (Chamaecyparis obtusa) and a large-scale rainfall simulator. Drop size distribution, drop velocity, and kinetic energy of throughfall varied spatially under a single canopy as did throughfall amount and rain rate. Compared with throughfall rain rate, the variability was similar in drop size distribution, lower in drop velocity, and higher in kinetic energy. The results suggest that the spatial distribution of throughfall amount was dominated by the canopy shape and position of branches inside the canopy, and thus the spatial distribution was correlated with the radial distance from the trunk. Throughfall amount and rate were lower at the midway point between the trunk and the canopy edge. Throughfall drop size indices (drop size distribution, drop velocity, and unit kinetic energy) varied spatially while did not differ significantly. On the other hand, time-specific throughfall kinetic energy was correlated with the radial distance from the trunk. The dependence the throughfall kinetic energy on the radial distance from the trunk was dominated by the spatial distribution of throughfall amount. The trend in the spatial distribution of throughfall revealed in this study will aid in modelling canopy water processes and in predicting soil erosion on the bare forest floor. 相似文献
999.
1000.
采用多元线性回归和通径分析方法,研究中华鳖日本品系主要经济性状对裙边重量的影响。结果表明,8个经济性状间的相关系数均达到显著水平;通过对各经济性状对裙边重量的通径分析和决定效应分析,发现背甲长对裙边重量的直接作用和直接决定效应均最大,其系数分别为0.505和0.255,是影响裙边重量最主要的性状,其次为腹甲宽。经多元回归分析,采用逐步回归方法,剔除偏回归系数不显著的性状,建立了背甲长(X_1)、腹甲宽(X_5)和体重(X_1)对裙边重量(Y_2)的最优回归方程:Y_2=15.4+1.741X_5+0.018Y_1+1.219X_1(R~2=0.881)。基于对裙边重量决定效应的大小,背甲长和腹甲宽可作为中华鳖日本品系良种选育的目标性状和裙边加工时获得优质裙边的重要参考。 相似文献