全文获取类型
收费全文 | 308篇 |
免费 | 12篇 |
专业分类
林业 | 7篇 |
农学 | 84篇 |
基础科学 | 1篇 |
30篇 | |
综合类 | 9篇 |
农作物 | 19篇 |
水产渔业 | 3篇 |
畜牧兽医 | 141篇 |
园艺 | 8篇 |
植物保护 | 18篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 34篇 |
2012年 | 17篇 |
2011年 | 14篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1970年 | 3篇 |
1967年 | 2篇 |
1964年 | 1篇 |
1938年 | 1篇 |
1936年 | 1篇 |
1915年 | 1篇 |
排序方式: 共有320条查询结果,搜索用时 15 毫秒
1.
2.
Diagnostic Value of Right Pulmonary Artery Distensibility Index in Dogs with Pulmonary Hypertension: Comparison with Doppler Echocardiographic Estimates of Pulmonary Arterial Pressure 下载免费PDF全文
3.
W. G. M. Bastiaanssen T. Van der Wal T. N. M. Visser 《Irrigation and Drainage Systems》1996,10(1):1-23
The success of water management in large irrigation schemes with composites of soil, crop, wetness and micro-meteorological conditions is difficult to quantify. Performance assessment indicators, being among others a function of evaporation, are useful tools to evaluate the actual functioning of an irrigation system. The inevitable spatial variability of evaporation in large irrigation schemes makes its determination with conventional point measurements almost impossible. A new remote sensing evaporation parameterization algorithm has been tested with high resolution Landsat Thematic Mapper data for the Eastern Nile Delta, Egypt. Although the implementation of such an algorithm requires assumptions to be made, the current case study shows that these assumptions do not hamper the estimation of actual and potential evaporation at regional scale. The actual evaporation has been used to express the uniformity of crop water use which is related to the equity of irrigation water distribution. The coefficient of variance in actual evaporation between 53 differenent irrigation districts is 10% on average. The relative evaporation was considered to determine whether the crop was adequately irrigated. The relative evaporation was more than 75% for 48 out of 53 irrigation districts. It is concluded, that improved information on actual crop growth conditions through remote sensing provides an essential insight into the planning of real-time and seasonal irrigation water deliveries. 相似文献
4.
Antoine LF Gady Freddy WK Hermans Marion HBJ Van de Wal Eibertus N van Loo Richard GF Visser Christian WB Bachem 《Plant methods》2009,5(1):13-14
Background
The establishment of mutant populations together with the strategies for targeted mutation detection has been applied successfully to a large number of organisms including many species in the plant kingdom. Considerable efforts have been invested into research on tomato as a model for berry-fruit plants. With the progress of the tomato sequencing project, reverse genetics becomes an obvious and achievable goal. 相似文献5.
A controlled trial was conducted to evaluate the persistent anthelmintic effect of ivermectin as a topical treatment at 500 μg/kg against induced infection with lungworm (Dicryocaulus viviparus) in red deer (Cervus elaphus). The results showed a highly significant (p < 0.01) anthelmintic activity for at least 28 days against a newly acquired infection with Dictyocauus viviparus (> 99% efficacy). 相似文献
6.
Foot-and-mouth disease (FMD) is endemic in many parts of the world and poses a permanent threat for cloven-hoofed animals in all countries. The available vaccines against FMD are safe and efficacious. Combat of FMD by vaccination is controversial in currently FMD-free countries including the ones of the European Union. The article summarizes our knowledge concerning production and use of vaccines, virus persistence, differentiation between vaccinated and infected animals, vaccination programs and perspectives of vaccine development. 相似文献
7.
Visser EK Van Reenen CG Rundgren M Zetterqvist M Morgan K Blokhuis HJ 《Equine veterinary journal》2003,35(2):176-183
REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212相似文献
8.
Effects of a porcine reproductive and respiratory syndrome virus infection on the development of the immune response against pseudorabies virus 总被引:5,自引:0,他引:5
De Bruin MG Samsom JN Voermans JJ van Rooij EM De Visser YE Bianchi AT 《Veterinary immunology and immunopathology》2000,76(1-2):125-135
The aim of this study was to investigate the effects of a porcine reproductive and respiratory syndrome virus (PRRSV) infection on the development of the immune response after pseudorabies virus (PRV) vaccination in pigs. Pigs were intranasally inoculated with the European PRRSV strain, Lelystad virus ter Huurne, and were vaccinated intramuscularly with PRV 2 weeks later (LV-PRV group). Control pigs were vaccinated with PRV only (PRV group). Eight weeks after PRV vaccination, pigs from both groups were challenged intranasally with wild-type PRV. We measured the lymphoproliferative, and the cytolytic responses to PRV of peripheral blood mononuclear cells (PBMC), isolated from blood samples. In addition, serum samples were examined for antibodies against PRV and LV. One week after PRV vaccination, PBMC proliferated abundantly to PRV in both groups. However, in the LV-PRV group the lymphoproliferative response declined after 1 week, whereas, in the PRV group, the lymphoproliferative response was high for 3 weeks and declined thereafter (P<0.05). After challenge, the lymphoproliferative response was 1 week earlier and was consistently and significantly higher in the PRV group than in the LV-PRV group. The PRV-specific killing was higher at 3 weeks after PRV vaccination and 5 weeks after PRV challenge 19+/-3 and 24+/-6%, respectively, in the PRV group, compared to 7+/-4 and 6+/-9%, respectively, in the LV-PRV group (P<0.05). However, later after vaccination and challenge the cytolytic response was identical in both groups. The antibody titre against PRV developed equally in both groups. After challenge, no PRV virus was isolated from both groups. From these results we conclude that, although PRRSV infection did cause changes in the time course of the T-lymphocyte response after PRV vaccination, PRRSV infection did not inhibit the development of vaccine-induced protection after PRV. 相似文献
9.
van Rooij EM Haagmans BL Glansbeek HL de Visser YE de Bruin MG Boersma W Bianchi AT 《Veterinary immunology and immunopathology》2000,74(1-2):121-136
Glycoproteins B (gB), gC and gD of pseudorabies virus (PRV) have been implicated as important antigens in protective immunity against PRV infection. As cell-mediated immunity plays a major role in this protective immunity, we determined the significance of these glycoproteins in the actual induction of cell-mediated immunity. We vaccinated pigs with plasmid DNA constructs coding for gB, gC or gD and challenged them with the virulent NIA-3 strain of pseudorabies virus. Vaccination with plasmid DNA coding for gB induced the strongest cell-mediated immune responses including cytotoxic T cell responses, whereas plasmid DNA coding for gD induced the strongest virus neutralising antibody responses. Interestingly, vaccination with gB-DNA reduced virus excretion early after challenge infection while vaccination with gC-DNA or gD-DNA did not.This is the first study to demonstrate that DNA vaccination induces cytotoxic T cell responses in pigs and that cell-mediated immunity induced by vaccination with gB-DNA is important for the reduction of virus excretion early after challenge infection. 相似文献
10.