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171.
S. M. Renaud D. L. Parry Luong-Van Thinh C. Kuo A. Padovan N. Sammy 《Journal of applied phycology》1991,3(1):43-53
The total protein, carbohydrate, lipid and ash compositions, and fatty acid contents of two species of marine microalgae,
the eustigmatophyte Nannochloropsis oculata (formerly ‘Chlorella sp., Japan’) and the chrysophyte Isochrysis sp. (Tahitian) used in tropical Australian mariculture, were studied. The microalgae were grown under a range of culture
conditions (41 and 601 laboratory culture, 3001 bag culture, and 80001 outdoor culture) and four light regimes (100 to 107
μ E m−2 s−1, 240 to 390 μ E m−2 s−1, 340 to 620 μ E m−2 s−1, and 1100 to 1200 μE m−2 s−1 respectively) to determine the effect of light intensity on the chemical composition of large scale outdoor cultures. Laboratory
and bag cultures were axenic and cultured in Walne medium while outdoor cultures were grown in a commercial medium designed
for optimum nutrition in tropical outdoor aquaculture operations. Change in growth medium and photon flux density produced
only small changes in the proximate biochemical composition of both algae. N. oculata and Isochrysis sp. both showed a trend towards slightly lower carbohydrate and higher chlorophyll a in shaded outdoor culture. Isochrysis sp. showed significant concentrations of the essential polyunsaturated fatty acid 22:6(n−3) (docosahexaenoic acid) from 5.3
to 10.3% of total fatty acid, and 20:5(n−3) (eicosapentaenoic acid) ranged from 0.6 to 4.1%. In contrast, N. oculata had high concentrations of 20:5(n−3) (17.8 to 39.9%) and only traces of 22:6(n−3). The fatty acid composition of Isochrysis sp. grown at high photon flux density (1100–1200 μE m−2 s−1) under outdoor culture showed a decrease in the percentage of several highly unsaturated fatty acids, including 20:5(n−3),
and an increase in 22:6(n−3). N. oculata showed a similar decrease in the percentage of 20:5(n−3). High light intensity caused a decrease in the ratio of total C16 unsaturated fatty acids to saturated 16:0 in N. oculata, and a decrease in the ratio of total C18 unsaturated fatty acids to saturated 18:0 together with a decrease in the ratio of total unsaturated fatty acids to total
saturated fatty acids in both microalgae. 相似文献
172.
Pharmaceuticals from cultured algae 总被引:1,自引:0,他引:1
Robert E. Schwartz Charles F. Hirsch David F. Sesin James E. Flor Michel Chartrain Robert E. Fromtling Guy H. Harris Michael J. Salvatore Jerrold M. Liesch Katherine Yudin 《Journal of industrial microbiology & biotechnology》1990,5(2-3):113-123
Summary An algae screening program, including cultured macroalgae, cultured cyanobacteria and cultured eukaryotic microalgae has been undertaken. Methods for the isolation, purification, preservation and cultivation of axenic cyanobacteria and eukaryotic cultures have been developed. Screening of these groups for biologically active components has lead to the isolation of pachydictyol and caulerpenyne from cultured macroalgae, while a series of hapalindoles and an antifungal depsipeptide have been isolated from cyanobacteria. 相似文献
173.
Malcolm R. Brown 《Journal of applied phycology》1995,7(5):495-500
Microalgae concentrates, prepared by centrifuging axenic (bacteria-free) cultures of Chaetoceros calcitrans (Paulsen) Takano, were processed and stored under different experimental conditions. The content of ascorbic acid was examined
in the concentrates, to assess potential changes in their nutritional properties. In algae pastes stored at 4 °C, it reduced
by 29% after 4 weeks storage. As most of the ascorbic acid was retained intracellularly (92%) after resuspension, most of
the cells had remained intact. In frozen and dried paste preparations, the losses of ascorbic acid ranged from minor (11%
after liquid nitrogen storage for 4 weeks) to major (≥94% after drying at 100 °C for 2 h or at 60 °C overnight). However,
most of the remaining ascorbic acid (>85%) in these preparations was rapidly leached from cells upon resuspension. Therefore,
pastes stored at 4 °C may have the best potential as an ‘off-the-shelf’ microalgal food product for mariculture. Pastes should
now be assessed in animal feeding trials, before being recommended for widespread use in the industry. 相似文献
174.
Kim J. M. Mulders Packo P. Lamers Dirk E. Martens René H. Wijffels 《Journal of phycology》2014,50(2):229-242
There is increasing interest in naturally produced colorants, and microalgae represent a bio‐technologically interesting source due to their wide range of colored pigments, including chlorophylls (green), carotenoids (red, orange and yellow), and phycobiliproteins (red and blue). However, the concentration of these pigments, under optimal growth conditions, is often too low to make microalgal‐based pigment production economically feasible. In some Chlorophyta (green algae), specific process conditions such as oversaturating light intensities or a high salt concentration induce the overproduction of secondary carotenoids (β‐carotene in Dunaliella salina (Dunal) Teodoresco and astaxanthin in Haematococcus pluvialis (Flotow)). Overproduction of all other pigments (including lutein, fucoxanthin, and phycocyanin) requires modification in gene expression or enzyme activity, most likely combined with the creation of storage space outside of the photosystems. The success of such modification strategies depends on an adequate understanding of the metabolic pathways and the functional roles of all the pigments involved. In this review, the distribution of commercially interesting pigments across the most common microalgal groups, the roles of these pigments in vivo and their biosynthesis routes are reviewed, and constraints and opportunities for overproduction of both primary and secondary pigments are presented. 相似文献
175.
176.
177.
To unlock the potential of Chlorella stigmatophora (Trebouxiophyceae, Chlorophyta) and Hemiselmis andersenii (Cryptophyceae, Cryptophyta) as natural reactors for biotechnological exploitation, their lipophilic extracts were characterized using Fourier Transform Infrared spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and Gas Chromatography-Mass Spectrometry (GC-MS) before and after alkaline hydrolysis. The GC-MS analysis enabled the identification of 62 metabolites—namely fatty acids (27), aliphatic alcohols (17), monoglycerides (7), sterols (4), and other compounds (7). After alkaline hydrolysis, monounsaturated fatty acids increased by as much as 87%, suggesting that the esterified compounds were mainly neutral lipids. Hemiselmis andersenii yielded the highest Σω3/Σω6 ratio (7.26), indicating that it is a good source of ω3 fatty acids, in comparison to C. stigmatophora (Σω3/Σω6 = 1.24). Both microalgae presented significant amounts of aliphatic alcohols (6.81–10.95 mg · g dw−1), which are recognized by their cholesterol-lowering properties. The multivariate analysis allowed visualization of the chemical divergence among H. andersenii lipophilic extracts before and after alkaline hydrolysis, as well as species-specific differences. Chlorella stigmatophora showed to be a valuable source of essential fatty acids for nutraceuticals, whereas H. andersenii, due to its high chemical diversity, seems to be suitable for different fields of application. 相似文献
178.
179.
Cadmium adsorption by the non-living biomass of microalgae grown in axenic mass culture 总被引:2,自引:0,他引:2
The freeze-dried (extracted and non-extracted) biomass of 15 microalgal species grown in axenic mass culture and belonging to the Cyanobacteria, Chloro-, Eustigmato-, Phaeo-, Rhodo- and Tribophyceae were investigated for their ability to adsorb cadmium (Cd) ions from aqueous solutions. For comparison, other standard adsorbing materials (activated carbon, silica gel, siliceous earth) were included in the studies. The biomass of 11 microalgae exhibited a higher Cd adsorption than the standard materials. Extraction of the algal biomass increased the Cd adsorption capability of some, but not all microalgae. High Cd adsorption was found inAnabaena lutea, Nodularia harveyana, andNostoc commune (Cyanobacteria),Chlamydomonas sp. (Chlorophyceae),Bumilleriopsis filiformis (Tribophyceae), and inEctocarpus siliculosus, Halopteris scoparia andSpermatochnus paradoxus (Phaeophyceae). The specific surface (m2 cm–3) of the various microalgae was determined by means of laser diffractometry.Anabaena inaequalis andA. lutea (Cyanobacteria) and the Phaeophyceae had especially high Cd adsorption per surface unit. Most of the Cd adsorbed to these various materials could be desorbed subsequently with diluted mineral acid (pH 2). 相似文献
180.
Flavonoids are important secondary plant metabolites believed to be present mainly in land plants. As phenolics were detected previously in microalgae using photometric assays, we wanted to investigate the nature of these phenolics and verify whether flavonoids are present. Therefore, in this study, we used state‐of‐the‐art ultra‐high performance liquid chromatography‐two‐dimensional mass spectrometry (UHPLC‐MS/MS) technology to investigate whether microalgae also contain flavonoids. For this, representative microalgal biomass samples from divergent evolutionary lineages (Cyanobacteria, Rhodophyta, Chlorophyta, Haptophyta, Ochrophyta) were screened for a set of carefully selected precursors, intermediates, and end products of the flavonoid biosynthesis pathways. Our data unequivocally showed that microalgae contain a wide range of flavonoids and thus must possess the enzyme pool required for their biosynthesis. Further, some of the microalgae displayed an intricate flavonoid pattern that is compatible with the established basic flavonoid pathway as observed in higher plants. This implies that the flavonoid biosynthesis pathway arose much earlier in evolution compared to what is generally accepted. 相似文献