全文获取类型
收费全文 | 54篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
58篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有58条查询结果,搜索用时 3 毫秒
21.
22.
Clarissa Hamaio Okino-Delgado Milene Stefani Pereira João Vitor Inácio da Silva Daniela Kharfan Débora Zanoni do Prado Luciana Francisco Fleuri 《Biotechnology progress》2019,35(1):e2734
Brazil is the world's leading orange supplier for juice production purposes. However, the production process generates high amount of wastes, which leads to disposal problems. Orange wastes can be used for lipases production, incorporating the biorefinery concept into juice industries. Thus, the aim of the present study was to investigate the wastes of orange production chain as source of lipases based on different varieties (Pera, Hamlin, Valencia, and Natal), as well as on different fractions of wastes. The mass balance of the juice/wastes (2007–2016 crops) was evaluated, and lipases from different varieties and fraction were biochemically characterized. Overall, the wastes corresponded to approximately 43% of the fruit mass. All the fractions of all varieties showed lipase activity in emulsified olive oil and in p-nitrophenyl substrates. The highest lipase activities were obtained by Natal pulp in emulsified olive oil, Natal frit, and Hamlin peel in p-NPB and Hamlin frit in p-NPL and p-NPP. The bagasse, peel, and frit lipases from the different orange varieties showed optimum pH from 6.0 to 8.0 and optimal temperature from 30 °C to 60 °C. Thus, it is possible concluding that the orange processing for juice production purposes generates a large amount of wastes, which can be destined to profitable purposes as lipases production. Lipases produced by different fractions and varieties are biochemically diverse, enabling the application a wide range of processes. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2734, 2019 相似文献
23.
Julia A Bell Jessica L St Charles Alice J Murphy Vijay AK Rathinam Anne E Plovanich-Jones Erin L Stanley John E Wolf Jenna R Gettings Thomas S Whittam Linda S Mansfield 《BMC microbiology》2009,9(1):57-22
Background
Campylobacter jejuni infection produces a spectrum of clinical presentations in humans - including asymptomatic carriage, watery diarrhea, and bloody diarrhea - and has been epidemiologically associated with subsequent autoimmune neuropathies. This microorganism is genetically variable and possesses genetic mechanisms that may contribute to variability in nature. However, relationships between genetic variation in the pathogen and variation in disease manifestation in the host are not understood. We took a comparative experimental approach to explore differences among different C. jejuni strains and studied the effect of diet on disease manifestation in an interleukin-10 deficient mouse model. 相似文献24.
TUBA BUCAK ECE SARAOĞLU ETİ E. LEVİ Ü. NİHAN TAVŞANOĞLU A. İdİl ÇAKİROĞLU ERIK JEPPESEN MERYEM BEKLİOĞLU 《Freshwater Biology》2012,57(8):1631-1642
1. Water‐level fluctuations are typical of lakes located in the semi‐arid Mediterranean region, which is characterised by warm rainy winters and hot dry summers. Ongoing climate change may exacerbate fluctuations and lead to more severe episodes of drought, so information on the effects of water level on the functioning of lake ecosystems in such regions is crucial. 2. In eutrophic Lake Eymir, Turkey, we conducted a 4‐month (summer) field experiment using cylindrical 0.8‐m‐ (low‐water‐level) and 1.6‐m‐deep (high‐water‐level) mesocosms (kept open to the sediment and atmosphere). Fish (tench, Tinca tinca, and bleak, Alburnus escherichii) were added to half of the mesocosms, while the rest were kept fishless. Ten shoots of Potamogeton pectinatus were transplanted to each mesocosm. 3. Sampling for physicochemical variables, chlorophyll a (chl‐a), zooplankton and per cent plant volume inhabited (PVI%) by macrophytes was conducted weekly during the first 5 weeks, and subsequently biweekly. Macrophytes were harvested on the last sampling date. During the course of the experiment, the water level decreased by 0.41 ± 0.06 m. 4. Throughout the experiment, fish affected zooplankton abundance (?), nutrient concentrations (+), chl‐a (+) and water clarity (?) most strongly in the low‐water‐level mesocosms and the zooplankton community shifted towards dominance of small‐sized forms. The fishless mesocosms had a higher zooplankton/phytoplankton ratio, suggesting higher grazing. 5. Greatest macrophyte growth was observed in the low‐water‐level fishless mesocosms. However, despite high nutrient concentrations and low water clarity, macrophytes were also abundant in the fish mesocosms and particularly increased following a water‐level decrease from midsummer onwards. Macrophyte growth was poor in the high‐water‐level mesocosms, even in the fishless ones with high water clarity. This was ascribed to extensive periphyton development reducing light availability for the macrophytes. 6. Our results indicate that a reduction in water level during summer may help maintain the growth of macrophytes in Mediterranean eutrophic shallow lakes, despite a strong negative effect of fish predation on water clarity. It is therefore probable that an expected negative effect of global climate change on water clarity because of eutrophication and enhanced top‐down control of fish may be, at least partly, counteracted by reduced water level, provided that physical disturbance is not severe. 相似文献
25.
LSB Mellau RJ Jørgensen PC Bartlett JMD Enemark AK Hansen 《Acta veterinaria Scandinavica》2004,45(3):139
The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1), the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2), control ration following a period with supplementation (3) and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4). Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets. 相似文献
26.
A high yield of nifedipine-chitosan microspheres could be obtained using an emulsification phase-separation method. A high level of entrapment of nifedipine in the microspheres was achieved. The microspheres exhibited excellent swelling properties. Differential scanning calorimetry, X-ray diffractometry, and scanning electron microscopy confirmed that at 1.84% loading, nifedipine was dispersed molecularly. The microspheres exhibited faster release at low loadings compared to high loadings. Fitting the data to the coupled Fickian/case II equation, showed that at low loadings polymer relaxation coefficients (k2) were high. As the polymer content increased in the microspheres, the value of n (diffusional exponent characteristic of the release mechanism) approached one, which is indicative of zero order. 相似文献
27.
Background
Many anticancer agents have poor water solubility and therefore the development of novel delivery systems for such molecules has received significant attention. Nanocarriers show great potential in delivering therapeutic agents into the targeted organs or cells and have recently emerged as a promising approach to cancer treatments. The aim of this study was to prepare and use poly-2-hydroxyethyl methacrylate (PHEMA) nanoparticles for the controlled release of the anticancer drug doxorubicin. 相似文献28.
29.
Ashirbad Pradhan Anita Anasuya Madan Mohan Pradhan Kavitha AK Priyanka Kar Krushna Chandra Sahoo Pinaki Panigrahi Ambarish Dutta 《PloS one》2016,11(2)
Background
Although Odisha is the largest contributor to the malaria burden in India, no systematic study has examined its malaria trends. Hence, the spatio-temporal trends in malaria in Odisha were assessed against the backdrop of the various anti-malaria strategies implemented in the state.Methods
Using the district-wise malaria incidence and blood examination data (2003–2013) from the National Vector Borne Disease Control Program, blood examination-adjusted time-trends in malaria incidence were estimated and predicted for 2003–2013 and 2014–2016, respectively. An interrupted time series analysis using segmented regression was conducted to compare the disease trends between the pre (2003–2007) and post-intensification (2009–2013) periods. Key-informant interviews of state stakeholders were used to collect the information on the various anti-malaria strategies adopted in the state.Results
The state annual malaria incidence declined from 10.82/1000 to 5.28/1000 during 2003–2013 (adjusted annual decline: -0.54/1000, 95% CI: -0.78 to -0.30). However, the annual blood examination rate remained almost unchanged from 11.25% to 11.77%. The keyinformants revealed that intensification of anti-malaria activities in 2008 led to a more rapid decline in malaria incidence during 2009–2013 as compared to that in 2003–2007 [adjusted decline: -0.83 (-1.30 to -0.37) and -0.27 (-0.41 to -0.13), respectively]. There was a significant difference in the two temporal slopes, i.e., -0.054 (-0.10 to -0.002, p = 0.04) per 1000 population per month, between these two periods, indicating almost a 200% greater decline in the post-intensification period. Although, the seven southern high-burden districts registered the highest decline, they continued to remain in that zone, thereby, making the achievement of malaria elimination (incidence <1/1000) unlikely by 2017.Conclusion
The anti-malaria strategies in Odisha, especially their intensification since 2008, have helped improve its malaria situation in recent years. These successful measures need to be sustained and perhaps intensified further for eliminating malaria from Odisha. 相似文献30.
On 15 November 2017 the mouth of the West Kleinemonde Estuary breached following heavy catchment rains and increased river flow. The water level in the estuary following mouth opening decreased by 1.65 m within 24 h, resulting in an almost complete draining of the littoral zone where large beds of the aquatic macrophyte Ruppia cirrhosa and mats of the associated filamentous algae were present. As the water depth within the plant beds decreased, the macrophytes, together with the algal filaments, created an increasingly dense mat, trapping fish that were resident, foraging or passing through the littoral zone. By 16 November 2017 large numbers of fishes belonging to at least 20 species were trapped in pools and depressions within the littoral, as well as within the R. cirrhosa beds and filamentous algal mats in the lower reaches of this system. Other affected taxa included crustaceans, especially isopods, and large numbers of small bivalves attached to macrophyte vegetation. Beneficiaries of the fish kill, in terms of unexpected food availability, included a variety of piscivorous bird species and the Cape clawless otter Aonyx capensis. This is the first documented account of a diverse species fish kill associated with estuary mouth breaching. 相似文献