全文获取类型
收费全文 | 920篇 |
免费 | 68篇 |
国内免费 | 2篇 |
专业分类
林业 | 68篇 |
农学 | 14篇 |
基础科学 | 3篇 |
132篇 | |
综合类 | 179篇 |
农作物 | 18篇 |
水产渔业 | 107篇 |
畜牧兽医 | 372篇 |
园艺 | 41篇 |
植物保护 | 56篇 |
出版年
2024年 | 7篇 |
2023年 | 11篇 |
2022年 | 11篇 |
2021年 | 28篇 |
2020年 | 31篇 |
2019年 | 37篇 |
2018年 | 34篇 |
2017年 | 21篇 |
2016年 | 30篇 |
2015年 | 30篇 |
2014年 | 24篇 |
2013年 | 53篇 |
2012年 | 56篇 |
2011年 | 78篇 |
2010年 | 40篇 |
2009年 | 30篇 |
2008年 | 47篇 |
2007年 | 62篇 |
2006年 | 60篇 |
2005年 | 53篇 |
2004年 | 44篇 |
2003年 | 37篇 |
2002年 | 36篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1963年 | 2篇 |
1942年 | 2篇 |
排序方式: 共有990条查询结果,搜索用时 0 毫秒
981.
Sperm cryopreservation in marine mollusk: a review 总被引:1,自引:0,他引:1
Yibing Liu Xiaoxu Li Nicholas Robinson Jianguang Qin 《Aquaculture International》2015,23(6):1505-1524
982.
Haruhisa Fukada Jon T. Dickey Andrew L. Pierce Nicholas Hodges Akihiko Hara Penny Swanson Walton W. Dickhoff 《Fish physiology and biochemistry》2003,28(1-4):335-336
The expression levels of growth hormone receptor (GHR) and insulin-like growth factor (IGF-I) in gonads of maturing coho salmon were measured by real-time PCR. The GHR and IGF-I mRNAs showed different gene expression pattern between male and female. These results suggest that a sexual dimorphism may exist in the GHR and IGF-I mRNA expressions of coho salmon during gonadal maturation 相似文献
983.
984.
985.
Soumesh K. Padhi Isaiah Tolo Margaret McEachran Alexander Primus Sunil K. Mor Nicholas B. D. Phelps 《Journal of fish diseases》2019,42(11):1609-1621
Koi herpesvirus (KHV; cyprinid herpesvirus‐3) and carp oedema virus (CEV) are important viruses of common and koi carp (Cyprinus carpio); however, the distribution of these viruses in wild common carp in North America is largely unknown. During the summers of 2017 and 2018, 27 mass mortalities of common carp were reported from four states in the USA (Minnesota, Iowa, Pennsylvania and Wisconsin), the majority of which were distributed across eight major watersheds in southern Minnesota. Samples from 22 of these mortality events and from five clinically healthy nearby carp populations were screened for KHV, CEV and SVCV using real‐time polymerase chain reaction (qPCR). KHV was confirmed in 13 mortality events, CEV in two mortality events and coinfections of KHV/CEV in four mortality events. Nucleotide sequence analysis revealed that the KHV and CEV detected here are closely related to European lineages of these viruses. While molecular detection alone cannot conclusively link either virus with disease, the cases described here expand the known range of two important viruses. This is also the first reported detection of KHV and CEV coinfections in wild carp populations. 相似文献
986.
Largemouth bass (LMB) Micropterus salmoides fry do not accept prepared diets at first feeding. Fry are initially reared in fertilized ponds on natural live foods until large enough to be feed trained. Unpredictable weather patterns and depletion of natural forages can affect nursery pond survival. A series of experiments was conducted to investigate the use of Artemia nauplii prepared diets and optimal feeding schedules to raise LMB fry from first feeding through habituation to a commercial dry diet. In Studies 1, 2, and 3, swim-up fry were transferred to a recirculating system and stocked into either 3-L (Studies 1 and 2) or 10-L (Study 3) acrylic aquaria. Study 1 screened candidate diets to evaluate whether LMB fry could be transitioned directly to prepared diets or if they required live foods. In Study 2 the optimum duration for feeding live Artemia (1, 2, or 3 weeks) and the appropriate size of commercial diets (<200 or 200–360 μm) were evaluated. Study 3 was designed to identify the best transitional feed. Results from Study 1 indicate that fry fed Otohime-A (<200 μm) and decapsulated Artemia cysts performed better than those fed other diets tested. However, survivals were low (6%–8%) indicating a need for live feed initially. In Trial 2, fry fed live Artemia nauplii for two weeks and then transitioned to a 200–360 μm diet (Otohime-B) performed better than other diet combinations tested. In Study 3, survival was significantly higher in treatments using decapsulated Artemia cysts or Otohime-B as transitional diets between initial live Artemia feeding and trout starter. These data indicate that LMB fry can be successfully raised from first feeding to fully habituated to a commercial trout starter by feeding live Artemia nauplii for two weeks, followed by a gradual transition to either decapsulated Artemia cysts or Otohime-B for one week, then gradually transitioning to trout starter. Surviving fish were easily transitioned to commercial floating feed (Study 4). This protocol yielded survival rates of approximately 70% and may improve the reliability of LMB fingerling production by eliminating the outdoor nursery pond phase. 相似文献
987.
在一个真的国际性跨学科和由各方人士(营养师、生物学家、政府官员和饲料公司相关人员)参与的营销效能(marketing effort 市场效能)研究中,日粮添加剂将妊娠母猪和哺乳母猪的生产性能提高到了一个令人惊讶的水平. 相似文献
988.
Windsor MA Carr BV Bankowski B Gibson D Reid E Hamblin P Gubbins S Juleff N Charleston B 《Veterinary research》2011,42(1):108
ABSTRACT: Infection of cattle with foot-and-mouth disease virus (FMDV) results in the development of long-term protective antibody responses. In contrast, inactivated antigen vaccines fail to induce long-term protective immunity. Differences between susceptible species have also been observed during infection with FMDV, with cattle often developing persistent infections whilst pigs develop more severe symptoms and excrete higher levels of virus. This study examined the early immune response to FMDV in na?ve cattle after in-contact challenge. Cattle exposed to FMDV were found to be viraemic and produced neutralising antibody, consistent with previous reports. In contrast to previous studies in pigs these cattle did not develop leucopenia, and the proliferative responses of peripheral blood mononuclear cells to either mitogen or third party antigen were not suppressed. Low levels of type 1 interferon and IL-10 were detected in the circulation. Taken together, these results suggest that there was no generalised immunosuppression during the acute phase of FMDV infection in cattle. 相似文献
989.
Journal of Plant Diseases and Protection - The commercial use of entomopathogenic nematodes after mass production requires the development of formulation techniques that extend nematode survival... 相似文献
990.