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111.
Assessment of the Microbial Community in a Constructed Wetland that Receives Acid Coal Mine Drainage 总被引:8,自引:0,他引:8
Constructed wetlands are used to treat acid drainage from surface or underground coal mines. However, little is known about
the microbial communities in the receiving wetland cells. The purpose of this work was to characterize the microbial population
present in a wetland that was receiving acid coal mine drainage (AMD). Samples were collected from the oxic sediment zone
of a constructed wetland cell in southeastern Ohio that was treating acid drainage from an underground coal mine seep. Samples
comprised Fe(III) precipitates and were pretreated with ammonium oxalate to remove interfering iron, and the DNA was extracted
and purified by agarose gel electrophoresis prior to amplification of portions of the 16S rRNA gene. Amplified products were
separated by denaturing gradient gel electrophoresis and DNA from seven distinct bands was excised from the gel and sequenced.
The sequences were matched to sequences in the GenBank bacterial 16S rDNA database. The DNA in two of the bands yielded matches
with Acidithiobacillus ferrooxidans and the DNA in each of the remaining five bands was consistent with one of the following microorganisms: Acidithiobacillus thiooxidans, strain TRA3-20 (a eubacterium), strain BEN-4 (an arsenite-oxidizing bacterium), an Alcaligenes sp., and a Bordetella sp. Low bacterial diversity in these samples reflects the highly inorganic nature of the oxic sediment layer where high abundance
of iron- and sulfur-oxidizing bacteria would be expected. The results we obtained by molecular methods supported our findings,
obtained using culture methods, that the dominant microbial species in an acid receiving, oxic wetland are A. thiooxidans and A. ferrooxidans. 相似文献
112.
Yashavanthi Niranjan Daniela Ungureanu Henrik Hammarén Arturo Sanz-Sanz Adrie H. Westphal Jan Willem Borst Olli Silvennoinen Riet Hilhorst 《Analytical biochemistry》2013
Förster resonance energy transfer (FRET) between the fluorescent ATP analogue 2′/3′-(N-methyl-anthraniloyl)-adenosine-5′-triphosphate (MANT–ATP) and enzymes is widely used to determine affinities for ATP–protein binding. However, in analysis of FRET fluorescence data, several important parameters are often ignored, resulting in poor accuracy of the calculated dissociation constant (Kd). In this study, we systematically analyze factors that interfere with Kd determination and describe methods for correction of primary and secondary inner filter effects that extend the use of the FRET method to higher MANT nucleotide concentrations. The interactions of the fluorescent nucleotide analogues MANT–ATP, MANT–ADP [2′/3′-O-(N-methylanthraniloyl) adenosine diphosphate], and MANT–AMP [2′/3′-O-(N-methylanthraniloyl) adenosine monophosphate] with the JAK2 tyrosine kinase domain are characterized. Taking all interfering factors into consideration, we found that JAK2 binds MANT–ATP tightly with a Kd of 15 to 25 nM and excluded the presence of a second binding site. The affinity for MANT–ADP is also tight with a Kd of 50 to 80 nM, whereas MANT–AMP does not bind. Titrations of JAK2 JH1 with nonhydrolyzable ATP analogue MANT–ATP-γ-S [2′/3′-O-(N-methylanthraniloyl) adenosine-5′-(thio)- triphosphate] yielded a Kd of 30 to 50 nM. The methods demonstrated here are applicable to other enzyme–fluorophore combinations and are expected to help improve the analysis of steady-state FRET data in MANT nucleotide binding studies and to obtain more accurate results for the affinities of nucleotide binding proteins. 相似文献
113.
Acetylcholinesterase (AChE) is the primary target for organophosphates (OP). Several mutations have been reported in AChE to be associated with the reduced sensitivity against OP in various arthropods. However, to the best of our knowledge, no such reports are available for Lepeophtheirus salmonis. Hence, in the present study, we aimed to determine the association of AChE(s) gene(s) with resistance against OP. We screened the AChE genes (L. salmonis ace1a and ace1b) in two salmon lice populations: one sensitive (n=5) and the other resistant (n=5) for azamethiphos, a commonly used OP in salmon farming. The screening led to the identification of a missense mutation Phe362Tyr in L. salmonis ace1a, (corresponding to Phe331 in Torpedo californica AChE) in all the samples of the resistant population. We confirmed the potential role of the mutation, with reduced sensitivity against azamethiphos in L. salmonis, by screening for Phe362Tyr in 2 sensitive and 5 resistant strains. The significantly higher frequency of the mutant allele (362Tyr) in the resistant strains clearly indicated the possible association of Phe362Tyr mutation in L. salmonis ace1a with resistance towards azamethiphos. The 3D modelling, short term survival experiments and enzymatic assays further supported the imperative role of Phe362Tyr in reduced sensitivity of L. salmonis for azamethiphos. Based on all these observations, the present study, for the first time, presents the mechanism of resistance in L. salmonis against azamethiphos. In addition, we developed a rapid diagnostic tool for the high throughput screening of Phe362Tyr mutation using High Resolution Melt analysis. 相似文献
114.
Saija LuukkanenMatti Haukka Olli LaineTapani Venäläinen Pirjo VainiotaloTapani A Pakkanen 《Inorganica chimica acta》2002,332(1):25-29
Chlorine containing ruthenium bipyridine carbonyl compounds react readily in dilute alkaline solutions under a CO atmosphere affording a poorly soluble and air sensitive product that is suggested to have a polymeric nature. Various analysis methods (MS and TPD) were used in the characterisation of the product. The replacement of the axial chloride ligands in trans(Cl), cis(CO)[Ru(bpy)(CO)2Cl2] and [Ru(bpy)(CO)2Cl]2 is proposed to be the initial step in the polymerisation. The replacement of chlorides in methanolic solution was confirmed by isolating and characterising the dimeric intermediate [Ru(bpy)(CO)2(COOCH3)]2. 相似文献
115.
Characterization of Jarosite Formed upon Bacterial Oxidation of Ferrous Sulfate in a Packed-Bed Reactor 总被引:5,自引:2,他引:3 下载免费PDF全文
A packed-bed bioreactor with activated-carbon particles as a carrier matrix material inoculated with Thiobacillus ferrooxidans was operated at a pH of 1.35 to 1.5 to convert ferrous sulfate to ferric sulfate. Despite the low operating pH, trace amounts of precipitates were produced in both the reactor and the oxidized effluent. X-ray diffraction and chemical analyses indicated that the precipitates were well-ordered potassium jarosite. The chemical analyses also revealed a relative deficiency of Fe and an excess of S in the reactor sample compared with the theoretical composition of potassium jarosite. 相似文献
116.
Abstract Several metal ions inhibited the oxygen uptake activity of Nitrobacter agilis , but their effects on the kinetic parameters of nitrite oxidation were mixed. Growth of Nitrobacter winogradskyi was inhibited by persulfate (>0.1 mM), tetrathionate (>0.5 mM), and trithionate (>5 mM). Oxygen uptake activity was, however, relatively insensitive to persulfate and tetrathionate ions. 相似文献
117.
Is it interspecific information use or aggression between putative competitors that steers the selection of nest‐site characteristics? A reply to Slagsvold and Wiebe 下载免费PDF全文
118.
Anne Usvalampi Hannu Maaheimo Olli Tossavainen Alexander D. Frey 《Glycoconjugate journal》2018,35(1):31-40
Fucosylated oligosaccharides have an important role in maintaining a healthy immune system and homeostatic gut microflora. This study employed a commercial β-galactosidase in the production of fucose-containing galacto-oligosaccharides (fGOS) from lactose and fucose. The production was optimized using experiment design and optimal conditions for a batch production in 3-liter scale. The reaction product was analyzed and the produced galactose-fucose disaccharides were purified. The structures of these disaccharides were determined using NMR and it was verified that one major product with the structure Galβ1–3Fuc and two minor products with the structures Galβ1–4Fuc and Galβ1–2Fuc were formed. Additionally, the product composition was defined in more detail using several different analytical methods. It was concluded that the final product contained 42% total monosaccharides, 40% disaccharides and 18% of larger oligosaccharides. 290 μmol of fGOS was produced per gram of reaction mixture and 37% of the added fucose was bound to fGOS. The fraction of fGOS from total oligosaccharides was determined as 44%. This fGOS product could be used as a new putative route to deliver fucose to the intestine. 相似文献
119.
120.
Vertical migration of two dinoflagellate species (Peridiniellacatenata and Scrippsiella hangoei) and a phototrophic ciliate(Mesodinium
rubrum) were studied during the peak and decline of avernal bloom at the SW coast of Finland. During the diel cycle, part
of thepopulations of P. catenata and M. rubrum wereobserved in the deeper layers with elevated nutrient concentrations, whileS.
hangoei remained in the upper nutrient depleted mixed layer.Using a correspondence analysis the vertical distribution patterns
of thespecies and chlorophyll a were examined over a temporal scale of hoursand weeks. The vertical migration was reflected
in much higher variabilityin the depth distribution of P. catenata and M. rubrum over a diel scale, compared to S. hangoei.
The analysisrevealed also significant differences in species specific depth distributionpatterns over both time scales. It
is discussed that the co-existence of thetwo dominant dinoflagellate species during the vernal bloom is due to nicheseparation
through behavioural adaptations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献