全文获取类型
收费全文 | 62975篇 |
免费 | 4068篇 |
国内免费 | 6157篇 |
专业分类
林业 | 4995篇 |
农学 | 3827篇 |
基础科学 | 3321篇 |
6590篇 | |
综合类 | 29441篇 |
农作物 | 4620篇 |
水产渔业 | 3521篇 |
畜牧兽医 | 9493篇 |
园艺 | 4550篇 |
植物保护 | 2842篇 |
出版年
2024年 | 346篇 |
2023年 | 1187篇 |
2022年 | 2750篇 |
2021年 | 2759篇 |
2020年 | 2578篇 |
2019年 | 2573篇 |
2018年 | 1872篇 |
2017年 | 3112篇 |
2016年 | 2086篇 |
2015年 | 2986篇 |
2014年 | 3231篇 |
2013年 | 3623篇 |
2012年 | 5149篇 |
2011年 | 5430篇 |
2010年 | 5259篇 |
2009年 | 4503篇 |
2008年 | 4601篇 |
2007年 | 4220篇 |
2006年 | 3463篇 |
2005年 | 2748篇 |
2004年 | 1777篇 |
2003年 | 1341篇 |
2002年 | 1537篇 |
2001年 | 1396篇 |
2000年 | 1181篇 |
1999年 | 489篇 |
1998年 | 143篇 |
1997年 | 122篇 |
1996年 | 120篇 |
1995年 | 99篇 |
1994年 | 72篇 |
1993年 | 74篇 |
1992年 | 61篇 |
1991年 | 72篇 |
1990年 | 47篇 |
1989年 | 34篇 |
1988年 | 40篇 |
1987年 | 32篇 |
1986年 | 27篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 5篇 |
1979年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1962年 | 11篇 |
1956年 | 24篇 |
1955年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
XU GuozhenCollege of Resources Environment Central South Forestry University. Zhuzhau . P.R. China 《中国林业科技(英文版)》2003,(4)
After analysis on the current situation of international forestry, this paper proposes that integration, coordination and sustainable development will be the general developing trend of forest in China, and commercial forest, ecological forest and community forest should be organically combined with integrative development and sustainable development in rural areas. This paper focuses especially on clarifying the importance of community forest to the social development or rural areas, and emphasizes that the key point of forestry should be turned from biological and technical aspects to humane and social aspects. 相似文献
993.
994.
随着农村产业化结构的调整,越来越多的农民走出了土地的圈子,离土离乡进城务工经商,导致农村养蚕劳力老年化、妇女化、文化素质低下,蚕桑技术的接受能力较弱,小蚕饲养水平低,严重影响蚕桑生产效益.为提高小蚕饲养水平,适应农村形势发展,我乡在县茧丝绸公司的支持、帮助下,于2001年春蚕期在联欢、曹家创办了两家小蚕公司,公司以饲养小蚕、出售小蚕解决农村养蚕实际问题为目的,进行小蚕专业化饲养,打破传统的养蚕方法,推行十天养蚕法,在饲养模式上进行一项改革.现将有关饲养情况通报如下. 相似文献
995.
涩宁兰输气管道工程进度控制 总被引:1,自引:0,他引:1
运用项目工程的控制理论,结合国内管道工程建设的经验,创建了涩宁兰管道工程建设管理模式,从对材料的采办、发放、现场调拔到对进度数据统计分析、预测及计划执行情况进行分析,及时、合理地调配资源,确保月计划的完成,以实现工期控制目标。 相似文献
996.
DENG Hua LI Hui YANG Hong ZHOU Zhaohai LIANG Haozhao XU Zhigao WU Fuda LI Qiaofeng HUANG Luqi 《畜牧兽医学报》1956,51(11):2836-2848
To study the clinicopathology and histopathology of African swine fever (ASF), and to explore the internal relationship between pathological changes and disease occurrence and development and its pathological mechanism, 13 Landrace pigs with bodyweight about 20 kg were intramuscular injected with African swine fever virus (ASFV), strain Pig/HLJ/18 at a dose of 102HAD50·mL-1. During the experiment, all the dead pigs were systematically dissected and sampled, paraffin sections were produced, and haematoxylin-eosin staining was performed. Clinicopathological evaluation standards for acute ASF were established, then pathological lesions (classification variables) were expressed by counting frequency and percentage, and the lesion degree (continuous variables) was graded and scored according to different pathological changes of various tissues and organs. The results showed that all infected pigs were in line with the clinical characteristics of ASF, including acute, febrile and highly infectious, with a 100% incidence rate and 100% mortality. The dead pigs showed typical characteristics of septicemia, cadavers prone to corruption, blood clotting adverse or hemolysis, rigor mortis incomplete. The main pathological lesions were hemorrhagic necrotizing lymphadenitis, acute inflammatory splenomegaly (septic spleen), cerebral edema, pulmonary edema and lung consolidation et al. The spleen and lymphonodus are the target organs attacked by ASFV, with the most significant lesions, the earliest occurrence time, the longest duration and the highest frequency. The most prominent pathological changes are blood circulation disorders, including multiple pathological manifestations such as edema, hyperemia, congestion, hemorrhage, infarction, disseminated intravascular coagulation (DIC), and the most important characteristics are hemorrhagic lesions. The inflammatory reaction of lymphocytic exudation caused by ASFV runs through the whole process, especially in the middle and later stages of the course. The results suggest that the main pathological process of acute African swine fever is a typical immune/inflammatory cascade reaction and severe systemic blood circulation disorder, which resulted in the high incidence rate and high mortality rate of acute ASF. 相似文献
997.
998.
999.
鸡骨型白血病免疫琼扩与放射摄片诊断的比较 总被引:1,自引:1,他引:0
为了探索特异性免疫学诊断方法对鸡骨型白血病(OP)的检测效果。用双盲法分批采样同时进行羽髓琼脂扩散试验和胫骨X线摄片检查对比,共检834只鸡(433羽属天然自发OP鸡群,401羽属人工诱发实验鸡群)。结果羽髓琼扩试验的OP阳性检出率为3.48%(29/834:)。阳性病理符合率为75.86%(22/29)。阳性误诊(假阳性)率24.13%(7/29),阴性误诊(假阴性)率36.15%(291/805)。而X线摄片检查的OP阳性检出率为38.37%(320/834)。X线阳性完全可获病理组织学证实,不存在假阳性或假阴性。把禽白血病羽髓琼扩试验试用于检测鸡骨型白血病尚属初次报道,其阳性检出率低而误诊率高,尚不宜作OP检测手段。放射摄片诊断的阳性检出率高而误诊率低,可快速诊断,故适用于OP检疫。 相似文献
1000.