全文获取类型
收费全文 | 254篇 |
免费 | 43篇 |
专业分类
林业 | 9篇 |
农学 | 7篇 |
基础科学 | 1篇 |
21篇 | |
综合类 | 35篇 |
农作物 | 4篇 |
水产渔业 | 12篇 |
畜牧兽医 | 204篇 |
植物保护 | 4篇 |
出版年
2023年 | 4篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 6篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1969年 | 5篇 |
1967年 | 2篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1960年 | 3篇 |
排序方式: 共有297条查询结果,搜索用时 750 毫秒
181.
Australian bat lyssavirus (ABLV) is a member of the Lyssavirus genus of the Rhabdoviridae family and is found in Australian bat species. It is of public health concern because of the rabies-like syndrome it causes in humans, resulting in government health and wildlife agencies using varied communication approaches to inform targeted audiences about zoonotic risks associated with handling bats. Despite these warnings, the number of reports of human-bat interactions remains high. This paper details a survey conducted to analyse the approaches utilised by a range of stakeholders to educate and communicate warnings to their target audiences. The survey focused on identifying the target audiences, communication methods used, along with the message frequency, content, and perceived effectiveness. Analysis of the top three messages delivered by stakeholders revealed that over half were information-focused messages and over a third, instruction-focused. Stakeholders identified the need to balance messaging about bat handling risks with information regarding the vulnerable status of bats and their environmental significance. Whilst the most common and (perceived) effective method of communication was one-on-one discussions, it was also identified to be ineffective for targeting mass audiences leading stakeholders to recognise the need to adapt to more efficient means of communication. The outcomes of this study may be useful to improve risk communication strategies regarding ABLV in Australia. 相似文献
182.
Mendelson JR Lips KR Gagliardo RW Rabb GB Collins JP Diffendorfer JE Daszak P Ibáñez D R Zippel KC Lawson DP Wright KM Stuart SN Gascon C da Silva HR Burrowes PA Joglar RL La Marca E Lötters S du Preez LH Weldon C Hyatt A Rodriguez-Mahecha JV Hunt S Robertson H Lock B Raxworthy CJ Frost DR Lacy RC Alford RA Campbell JA Parra-Olea G Bolaños F Domingo JJ Halliday T Murphy JB Wake MH Coloma LA Kuzmin SL Price MS Howell KM Lau M Pethiyagoda R Boone M Lannoo MJ Blaustein AR Dobson A Griffiths RA 《Science (New York, N.Y.)》2006,313(5783):48
183.
184.
Joint effusion is one of the classic radiographic signs of osteoarthritis, but no information is available regarding clinicians' ability to detect joint effusion radiographically. This study determined the accuracy and precision of experienced and inexperienced observers in detecting joint effusion of the distal interphalangeal (DIP), metacarpophalangeal (MCP) and midcarpal joints on radiographs. Fresh cadaverous forelimbs were loaded in a material testing machine to mimic a standing horse. The joints were gradually distended and lateromedial and dorsopalmar radiographs were acquired. The images were assessed by three experienced and three inexperienced observers. This study showed that the sensitivity was high for both groups for all joints and projections. Specificity was high for the experienced group but low for the inexperienced group. There was a significant positive correlation between joint distension and severity of joint effusion when reported by experienced observersfor most views (except DIP joint), but only for the MCP joint for inexperienced observers. Interoperator agreement was poor to fair for the experienced group and poor for the inexperienced group. In conclusion, the accuracy and precision of grading joint effusion on radiographs was highly subjective and related to experience. 相似文献
185.
Intestinal dysmotility following equine colic surgery contributes negatively to financial and prognostic outcomes. This study assessed duodenal contractility as a predictor of post-operative reflux and survival to discharge in horses following colic surgery. Duodenal contractility was assessed using daily transabdominal ultrasound examinations in 49 horses for up to 7 days (Day 1 scan performed between 6 and 36 h post-surgery and sequential daily scans performed between 08.00 and 20.00 h) following colic surgery (September 2014–April 2017). The duodenum was visualised ventral to the right kidney, and duodenal contractions were measured over 2 min. The signalment of each horse and surgical findings were noted. Outcomes were defined as horses that refluxed (>5 L/24 h beyond 24 h) or did not reflux post-operatively and those that were survivors or were nonsurvivors. A significant difference in duodenal contractions at Day 1 post-operatively was identified between horses that refluxed (n = 8) and those who did not reflux (n = 32; P = 0.013) but not between those who were nonsurvivors (n = 7) and survivors (n = 32; P = 0.113). Horses in the reflux group had reduced duodenal contractility comparatively. There were no significant differences in duodenal contractions in the sequential days after the Day 1 scan or between duodenal contractions and surgical findings. A significant association was identified between duodenal contractions and survivors (P = 0.039; odds ratio 1.88). The main study limitations were the single centre design with consequent small numbers of horses included. The study did not account for other factors that may contribute to alterations in motility such as drug administration or stages of re-feeding. This preliminary study indicates that Day 1 (6–36 h post-operatively) duodenal contractions may predict reflux (>5 L/24 h beyond 24 h) and that increased duodenal contractions are associated with survival. However, there was no clear distinction or cut-off between groups. Future studies with greater numbers of horses yielding better statistical power are required. 相似文献
186.
187.
Davis BM Lawson EH Sandkvist M Ali A Sozhamannan S Waldor MK 《Science (New York, N.Y.)》2000,288(5464):333-335
Virulence of Vibrio cholerae depends on secretion of cholera toxin (CT), which is encoded within the genome of a filamentous phage, CTXphi. Release of CT is mediated by the extracellular protein secretion (eps) type II secretion system. Here, the outer membrane component of this system, EpsD, was shown to be required for secretion of the phage as well. Thus, EpsD plays a role both in pathogenicity and in horizontal transfer of a key virulence gene. Genomic analysis suggests that additional filamentous phages also exploit chromosome-encoded outer membrane channels. 相似文献
188.
The heat capacities of AgMo(4)S(5), PbMo(6)S(7), and SnMo(5)S(6) are reported. These ternary molybdenum sulfides have been found to be bulk superconductors with very large values of electronic heat capacity coefficients and very low values of Debye temperatures. 相似文献
189.
Lawson DA 《Science (New York, N.Y.)》1975,187(4180):947-948
Three partial skeletons of a large pterosaur have been found in the latest Cretaceous nonmarine rock of West Texas. This flying reptile had thin, elongate, perhaps toothless jaws and a long neck similar to Pterodaustro and Pterodactylus. With an estimated wingspan of 15.5 meters, it is undoutbtedly the largest flying creature presently known. 相似文献
190.
Tzedakis PC Lawson IT Frogley MR Hewitt GM Preece RC 《Science (New York, N.Y.)》2002,297(5589):2044-2047
A high-resolution pollen record from western Greece shows that the amplitude of millennial-scale oscillations in tree abundance during the last glacial period was subdued, with temperate tree populations surviving throughout the interval. This provides evidence for the existence of an area of relative ecological stability, reflecting the influence of continued moisture availability and varied topography. Long-term buffering of populations from climatic extremes, together with genetic isolation at such refugial sites, may have allowed lineage divergence to proceed through the Quaternary. Such ecologically stable areas may be critical not only for the long-term survival of species, but also for the emergence of new ones. 相似文献