全文获取类型
收费全文 | 768篇 |
免费 | 109篇 |
国内免费 | 1篇 |
专业分类
林业 | 56篇 |
农学 | 41篇 |
基础科学 | 10篇 |
112篇 | |
综合类 | 58篇 |
农作物 | 33篇 |
水产渔业 | 83篇 |
畜牧兽医 | 443篇 |
园艺 | 8篇 |
植物保护 | 34篇 |
出版年
2023年 | 8篇 |
2022年 | 15篇 |
2021年 | 28篇 |
2020年 | 21篇 |
2019年 | 36篇 |
2018年 | 41篇 |
2017年 | 34篇 |
2016年 | 25篇 |
2015年 | 30篇 |
2014年 | 40篇 |
2013年 | 49篇 |
2012年 | 43篇 |
2011年 | 47篇 |
2010年 | 33篇 |
2009年 | 25篇 |
2008年 | 35篇 |
2007年 | 24篇 |
2006年 | 29篇 |
2005年 | 30篇 |
2004年 | 20篇 |
2003年 | 18篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1968年 | 5篇 |
排序方式: 共有878条查询结果,搜索用时 15 毫秒
871.
Debasis MITRA Sergio DE LOS SANTOS-VILLALOBOS Fannie Isela PARRA-COTA Ana Mara Garcia MONTELONGO Erika Lorena BLANCO Vanessa L. LIRA Adeyemi N. OLATUNBOSUN Bahman KHOSHRU Rittick MONDAL Parameswaran CHIDAMBARANATHAN Periyasamy PANNEERSELVAM Pradeep K. DAS MOHAPATRA 《土壤圈》2023,33(2):268-286
Various microorganisms live in association with different parts of plants and can be harmful, neutral, or beneficial to plant health. Some microbial inhabitants of plants can control plant diseases by contesting with, predating on, or antagonizing plant pathogens and by inducing systems for plant defense. A range of methods, including plant growth-promoting microorganisms(PGPMs) as biological control agents(BCAs)(BCA-PGPMs) are used for the biological management and control of plant pathogens. S... 相似文献
872.
This study was a follow up to the study on the gross anatomy of the male agouti ( Dasyprocta leporina ) reproductive system. The seminal vesicles of the agouti are lobulated structures. The mean diameter of the large lumen is 883.6 ± 76.83 μm. The mucosa (24.1 ± 0.92 μm), which is lined by pseudo-stratified columnar epithelium is thrown into folds, which often branch. The lamina muscularis mucosa is thin and is made of loose connective tissue containing blood vessels. The mucosa of the leaf-like coagulating glands of the agouti is folded. The mean diameter of the lumen is 488.3 ± 41.96 μm. The mucosa contains tubuloalveolar glands, which have a mean length of 199.5 ± 28.83 μm. The thin epithelium, 15.0 ± 1.25-μm wide, consists mostly of pseudo-stratified columnar cells. The epithelium also has surface modifications in the form of apical blebs and cilia. The epithelium of the agouti's lobulated prostate gland is also folded creating a large lumen with a mean diameter of 995.5 ± 55.70 μm. The mucosa contains tubular and tubuloalveolar glands, each having a mean length of 134.4 ± 13.59 μm. The epithelium (13.9 ± 1.16 μm) consists of pseudo-stratified columnar cells. The pea-shaped bulbourethral gland (BG) of the agouti consists of convoluted tubular, mucous secretory units, which are irregularly shaped each with a mean length of 177.9 ± 7.10 μm and a mean width of 63.5 ± 3.97 μm. The BG of the agouti are ventro-lateral to the rectum and dorsally positioned to the pubic symphysis, and connected to the urethra by short ducts. 相似文献
873.
dos Santos DR Vitral CL de Paula VS Marchevsky RS Lopes JF Gaspar AM Saddi TM Júnior NC Guimarães Fde R Júnior JG Ximenes LL Souto FJ Pinto MA 《Veterinary journal (London, England : 1997)》2009,182(3):474-480
Active hepatitis E virus (HEV) infections in two Brazilian swine herds were investigated. In study 1, 26 piglets born to five anti-HEV positive sows were monitored from birth to post-partum week 22. Serum samples were screened for the detection of anti-HEV antibodies and a nested RT-PCR used to examine the HEV genome. Passive transfer of immunity was confirmed. At week 22, 23/26 (88.4%) of the piglets had seroconverted. Genome amplification was achieved in a feces pool from one holding pen and in one serum sample, both from 13-week-old animals. Histology was suggestive of a potential HEV infection. In the second study, 47 piglets born to six anti-HEV-positive sows were monitored after weaning. Seroconversion was determined in eight animals at 6-8 weeks of age. HEV RNA was detected in two pools from a holding pen for 12-16-week-old animals. Brazilian isolates were classified as genotype 3. This is the first molecular evidence of HEV infection in Brazilian pig herds. 相似文献
874.
875.
Shakeel Ahmad Ashfaq Ahmad Hakoomat Ali Abid Hussain Axel Garcia y Garcia Muhammad Azam Khan Muhammad Zia-Ul-Haq Mirza Hasanuzzaman Gerrit Hoogenboom 《Irrigation Science》2013,31(3):491-506
The objectives of this study were to evaluate the performance of the Cropping System Model (CSM)-CERES (Crop-Environment Resource Synthesis)-Rice for simulating growth and yield of rice under irrigated conditions for a semiarid environment in Pakistan and to determine the impact of plant density and irrigation regime on grain yield and economic returns. The crop simulation model was evaluated with experimental data collected in 2000 and 2001 in Faisalabad, Punjab, Pakistan. The experiment utilized a randomized complete block design with three replications and included three plant densities (one seedling hill?1, PD1; two seedlings hill?1, PD2; and three seedlings hill?1, PD3) and five irrigation regimes (625 mm, I1; 775 mm, I2; 925 mm, I3; 1075 mm, I4; and 1225 mm, I5). To determine the most appropriate combination of plant densities and irrigation regimes, four plant densities from one seedling hill?1 to four seedlings hill?1 and 17 irrigation regimes ranging from 0 to 1600 mm, for a total of 68 different scenarios, were simulated for 35 years of historical daily weather data. The evaluation of CSM-CERES-Rice showed that the model was able to accurately simulate growth and yield of rice for irrigated semiarid conditions, with an average error of 11% between simulated and observed grain yield. The results of the biophysical analysis showed that the combination of the two seedlings hill?1 plant density and the 1,300 mm irrigation regime produced the highest yield compared to all other scenarios. Furthermore, the economic analysis through the Mean-Gini Dominance (MGD) also showed the superiority of this treatment compared to the other treatment combinations. The mean monetary return ranged from ?47 to 1,265 $ ha?1 among all 68 scenarios. However, to be able to furnish the demand of rice grain for local consumption and to increase export, there is a need to expand this technology among the rice growers of other rice producing areas in Pakistan through extension workers. 相似文献
876.
877.
J. D. Garcia Perez C. Charlton P. Martin Ruiz 《Land Degradation \u0026amp; Development》1995,6(3):149-161
This paper proposes a methodological approach to data gathering as a sound basis for understanding land degradation processes, breaking down barriers of distrust between Government officials and land users, and promoting participation in planning for soil and water conservation. It examines how landscape changes, of value as indicators of erosion, are perceived by land users and can be used in planning. It is proposed that the participation of land users in the construction of questionnaires, data gathering, analysis and writing up of the findings are examples of the participatory initial stages in planning. 相似文献