全文获取类型
| 收费全文 | 94篇 |
| 免费 | 4篇 |
专业分类
| 林业 | 10篇 |
| 农学 | 3篇 |
| 15篇 | |
| 综合类 | 18篇 |
| 农作物 | 4篇 |
| 水产渔业 | 15篇 |
| 畜牧兽医 | 19篇 |
| 园艺 | 6篇 |
| 植物保护 | 8篇 |
出版年
| 2023年 | 2篇 |
| 2022年 | 3篇 |
| 2021年 | 4篇 |
| 2020年 | 1篇 |
| 2019年 | 9篇 |
| 2018年 | 5篇 |
| 2017年 | 2篇 |
| 2016年 | 6篇 |
| 2015年 | 2篇 |
| 2014年 | 3篇 |
| 2013年 | 4篇 |
| 2012年 | 7篇 |
| 2011年 | 14篇 |
| 2010年 | 6篇 |
| 2009年 | 3篇 |
| 2008年 | 4篇 |
| 2007年 | 4篇 |
| 2006年 | 6篇 |
| 2005年 | 4篇 |
| 2004年 | 1篇 |
| 2003年 | 2篇 |
| 1999年 | 1篇 |
| 1998年 | 1篇 |
| 1987年 | 1篇 |
| 1985年 | 1篇 |
| 1979年 | 1篇 |
| 1924年 | 1篇 |
排序方式： 共有98条查询结果，搜索用时 484 毫秒
71.
72.
Frank D Appelqvist I Piyasiri U Delahunty C 《Journal of agricultural and food chemistry》2012,60(9):2264-2273
The presence of fat in food plays an important role in the way aroma is released during consumption and in the creation of the overall sensory impression. Fat acts as a reservoir for lipophilic volatile compounds and modulates the timing and delivery of aroma compounds in a unique manner. Despite considerable research, reproducible in vitro methods for measuring the effect of fat on volatile release are lacking. An open in vitro cell was used to simulate the open human naso-oropharygeal system and was interfaced with a proton transfer reaction mass spectrometer (PTR-MS) to examine some of the fundamental effects of fat on dynamic volatile release in liquid fat emulsions. Lipid emulsions with various fat contents (0-20%) and droplet sizes (0.25, 0.5, and 5.0 μM) were spiked with flavor volatiles representing a range of lipophilicity (K(o/w) = 1-1380). Preloaded syringes of spiked emulsion were injected into the cell, and temporal changes in release were measured under dynamic conditions. Significant differences in release curves were measured according to the lipid content of emulsions, the vapor pressure, and K(o/w) values of the volatile compounds. With increasing addition of fat, the critical volatile release parameters, maximum concentration (I(max)), time to maximum concentration (T(max)), and the integrated area under the concentration curve (AUC), were affected. The in vitro curves were reproducible and in agreement with theory and correlated with the preswallow phase of in vivo release data. An exponential model was used to calculate changes in mass transfer rates with increased fat addition. 相似文献
73.
M. I. Crișan A. Damian I. Morar E. Páll C. Peștean I. Șt. Groza 《Anatomia, histologia, embryologia》2016,45(5):329-337
The ability to choose the sex of the offspring is of upmost economic importance for horse breeders. Unlike other species, horses present several reproductive peculiarities that interfere with assisted reproductive technologies used in other large animals (such as bovine) and make them difficult to apply. Thus, there is a great interest to determine the sex of the offspring as soon as possible. This has led to the development of several technologies to serve this purpose, which can be classified into two categories. One is equine embryo sexing by either non‐invasive biotechnological methods, such as monitoring of X‐linked enzymes before X chromosome inactivation and detection of sex‐specific antigen, or by invasive biotechnological methods, such as cytogenetic analysis and polymerase chain reaction (PCR). The other one is equine foetus sexing using ultrasound scanning in different stages of its development (early, mid or late), by different approaches (transrectally or transabdominally). This can be performed with classic B‐mode ultrasound machines or using 3D‐mode and Doppler‐mode scanners. This review article offers a comprehensive overview of the current status of these procedures as well as an assessment of their interests and applicability. 相似文献
74.
75.
Kevin D. Friedland Ryan E. Morse James P. Manning Donald Christopher Melrose Travis Miles Andrew G. Goode Damian C. Brady Josh T. Kohut Eric N. Powell 《Fisheries Oceanography》2020,29(5):396-414
Temperature is an important factor in defining the habitats of marine resource species. While satellite sensors operationally measure ocean surface temperatures, we depend on in situ measurements to characterize benthic habitats. Ship‐based measurements were interpolated to develop a time series of gridded spring and fall, surface and bottom temperature fields for the US Northeast Shelf. Surface and bottom temperatures have increased over the study period (1968–2018) at rates between 0.18–0.31°C per decade and over a shorter time period (2004–2018) at rates between 0.26–1.49°C per decade. A change point analysis suggests that a warming regime began in the surface waters in 2011 centered on Georges Bank and the Nantucket Shoals; in following years, most of the Northeast Shelf had experienced a shift in surface temperature. A similar analysis of bottom temperature suggests a warming regime began in 2008 in the eastern Gulf of Maine; in following years, change points in temperature occurred further to the west in the Gulf of Maine, finally reaching the Middle Atlantic Bight by 2010. The spatial pattern in bottom water warming is consistent with well‐known oceanographic patterns that advect warming North Atlantic waters into the Gulf of Maine. The varying spatial and temporal progression of warming in the two layers suggests they were actuated by different sets of forcing factors. We then compared these trends and change points to responses of lower and higher trophic level organisms and identified a number of coincident shifts in distribution and biomass of key forage and fisheries species. 相似文献
76.
77.
- 1. Populations of white‐clawed crayfish (Austropotamobius pallipes) have undergone substantial declines across Europe. Remaining populations tend to be fragmented and in many catchments they are restricted to upland streams. Information is needed concerning their spatial ecology to assist with conservation and rehabilitation of existing fragmented populations, as well as possible reintroductions.
- 2. A novel method for the long‐term tagging of white‐clawed crayfish was used to study the spatial ecology of a white‐clawed crayfish population fragment in a small, moderate‐gradient upland stream. Internal passive integrated transponder (PIT) tags enabled adult crayfish (carapace length >27 mm) to be permanently tagged, each with a unique identification code and resulted in a high number of recaptures. Of 501 crayfish tagged 413 were subsequently relocated at least once.
- 3. Crayfish did not make extensive movements, the median annual distance moved was 84.8 m yr?1, equivalent to annual net movement of 0.233 m day?1, substantially less than reported in previous studies. The lower levels of movement may reflect the study encompassing all seasons, including winter, when crayfish are relatively inactive.
- 4. Significantly more crayfish moved downstream compared with upstream and distances moved downstream were significantly greater than those in an upstream direction. This may be linked to the relatively high gradient of the stream and a reduced passability of the abundant riffles to upstream movements of crayfish.
- 5. A small weir acted as a barrier within the stream, preventing upstream movements of crayfish. Even small barriers may limit the movements of white‐clawed crayfish and have the potential to limit connectivity within populations and prevent expansion or recolonization.
- 6. The results presented suggest that fragmented populations of white‐clawed crayfish in upland streams are unlikely to expand rapidly and reconnect to other population fragments, even where habitat is suitable. In establishing stream populations care should be taken to ensure that even small barriers to movement are removed unless these are intended to exclude non‐native biota, especially crayfish.
78.
Maria Surma Anetta Kuczy&#x;ska Krzysztof Miko&#x;ajczak Piotr Ogrodowicz Tadeusz Adamski Hanna &#x;wiek‐Kupczy&#x;ska Aneta Sawikowska Alicja Pecio Damian Wach Grzegorz Jzefaciuk Ma&#x;gorzata &#x;ukowska Jzef Zych Pawe&#x; Krajewski 《Journal of Agronomy and Crop Science》2019,205(3):295-308
The yield potential of 60 spring barley varieties was examined under controlled drought and natural conditions in the years 2011–2013. The studied varieties were genotyped with the 1536‐SNP barley oligonucleotide assay. In experiments with controlled drought conditions, the grain yield, 1,000‐grain weight, number of productive tillers and length of the main stem were measured. Physicochemical properties such as the specific surface area, water adsorption energy, fractal dimension and nanopore radius of the plant leaves were determined and correlated with yield‐forming traits. Field trials were conducted over 3 years at 14 locations, where along with the yield‐related traits, monthly rainfall and average temperature were monitored. Five varieties of high yield and five varieties relatively stable under both semi‐controlled and natural conditions were distinguished. The yield‐related traits observed in various locations were related to environmental variables relevant to water availability. The sum of the rainfall in April and May was negatively correlated with the 1,000‐grain weight and positively with the plant height. Positive relationships were found between plant height and temperatures in June and July. Five markers detected earlier as linked to the quantitative trait loci in the mapping populations were identified to have a coherent effect among varieties of various pedigree. 相似文献
79.
黄曲霉毒素是一种毒性很强的霉菌毒素,广泛存在于奶牛饲料原料中,严重影响奶牛生产性能的发挥和体质健康,并通过代谢形成黄曲霉毒素M1残留于牛奶中直接危害人体健康。本文论述了黄曲霉毒素的产生、分布与残留情况,同时针对黄曲霉毒素的危害提出了预防控制措施,特别是对几种霉菌毒素脱毒剂的脱毒效果与脱毒机制进行了综述。 相似文献
80.