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111.
Hierarchical Zn–Co–S Nanowires as Advanced Electrodes for All Solid State Asymmetric Supercapacitors 下载免费PDF全文
A facile two‐step strategy is developed to design the large‐scale synthesis of hierarchical, unique porous architecture of ternary metal hydroxide nanowires grown on porous 3D Ni foam and subsequent effective sulfurization. The hierarchical Zn–Co–S nanowires (NWs) arrays are directly employed as an electrode for supercapacitors application. The as‐synthesized Zn–Co–S NWs deliver an ultrahigh areal capacity of 0.9 mA h cm?2 (specific capacity of 366.7 mA h g?1) at a current density of 3 mA cm?2, with an exceptional rate capability (≈227.6 mA h g?1 at a very high current density of 40 mA cm?2) and outstanding cycling stability (≈93.2% of capacity retention after 10 000 cycles). Most significantly, the assembled Zn–Co–S NWs//Fe2O3@reduced graphene oxide asymmetric supercapacitors with a wide operating potential window of ≈1.6 V yield an ultrahigh volumetric capacity of ≈1.98 mA h cm?3 at a current density of 3 mA cm?2, excellent energy density of ≈81.6 W h kg?1 at a power density of ≈559.2 W kg?1, and exceptional cycling performance (≈92.1% of capacity retention after 10 000 cycles). This general strategy provides an alternative to design the other ternary metal sulfides, making it facile, free‐standing, binder‐free, and cost‐effective ternary metal sulfide‐based electrodes for large‐scale applications in modern electronics. 相似文献
112.
Achary A Hariharan KA Bandhyopadhyaya S Ramachandran R Jayaraman K 《Biotechnology and bioengineering》1997,55(1):148-154
D-Hydantoinases (E.C.3.5.2.2) are commercially valuable enzymes involved in the production of D-amino acids. However, commercial exploitation of the biological process is rare, mainly because sufficient details are not available on the efficient production of these enzymes by microorganisms. In the present study, Agrobacterium radiobacter was used as the source of D-hydantoinase and its production was optimized with inexpensive carbon and nitrogen sources. The four media components selected to study their effect on biomass and/or enzyme activities were molasses, ammonium nitrate, sodium di-hydrogen orthophosphate, and manganese chloride. With the use of an empirical modeling technique (response surface method), we have optimized both biomass and enzyme production in this organism, with a minimal number of batches. Experiments were performed with optimized media components to validate the model. The maximum level of enzyme and biomass obtained was 35 U/mL and 1.69 mg/mL, respectively. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 148-154, 1997. 相似文献
113.
Axenic aerobic biofilms inhibit corrosion of SAE 1018 steel through oxygen depletion 总被引:1,自引:0,他引:1
A. Jayaraman E. T. Cheng J. C. Earthman T. K. Wood 《Applied microbiology and biotechnology》1997,48(1):11-17
Corrosion inhibition of SAE 1018 steel by pure-culture biofilms of Pseudomonas fragi and Escheri-chia coli DH5α has been evaluated in complex Luria-Bertani medium, seawater-mimicking medium, and modified Baar's medium at 30 °C.
In batch cultures, both bacteria inhibited corrosion three to six fold compared to sterile controls, and the corrosion was
comparable to that observed in anaerobic sterile media. To corroborate this result, a continuous reactor and electrochemical
impedance spectroscopy were used to show that both P. fragi K and E. coli DH5α decreased the corrosion rate by 4- to 40-fold as compared to sterile controls; this matched the decrease in corrosion
found with sterile medium in the absence of oxygen and with E. coli DH5α grown anaerobically. In addition, the requirement for live respiring cells was demonstrated by the increase in the corrosion
rate that was observed upon killing the P. fragi K biofilm in continuous cultures, and it was shown that fermentation products do not cause an increase in corrosion. Hence,
pure-culture biofilms inhibit corrosion of SAE 1018 steel by depleting oxygen at the metal surface.
Received: 16 December 1996 / Received revision: 18 March 1997 / Accepted: 27 March 1997 相似文献
114.
Corrosion inhibition by aerobic biofilms on SAE 1018 steel 总被引:5,自引:0,他引:5
Carbon steel (SAE 1018) samples were exposed to complex liquid media containing either the aerobic bacterium Pseudomonas fragi or the facultative anaerobe Escherichia coli DH5α. Compared to sterile controls, mass loss was consistently 2- to 10-fold lower in the presence of these bacteria which
produce a protective biofilm. Increasing the temperature from 23 °C to 30 °C resulted in a 2- to 5-fold decrease in corrosion
inhibition with P. fragi whereas the same shift in temperature resulted in a 2-fold increase in corrosion inhibition with E. coli DH5α. Corrosion observed with non-biofilm-forming Streptomyces lividans TK24 was similar to that observed in sterile media. A dead biofilm, generated in situ by adding kanamycin to an established biofilm, did not protect the metal (corrosion rates were comparable to those in the
sterile control), and mass loss in cell-free, spent Luria-Bertani (LB) medium was similar to that in sterile medium. Confocal
laser scanning microscopy analysis confirmed the presence of a biofilm consisting of live and dead cells embedded in a sparse
glycocalyx matrix. Mass-loss measurements were consistent with microscopic observations of the metal surface after 2 weeks
of exposure, indicating that uniform corrosion occurred. The biofilm was also able to withstand mild agitation (60 rpm), provided
that sufficient time was given for its development.
Received: 3 May 1996 / Received revision: 8 August 1996 / Accepted: 24 August 1996 相似文献
115.
S. Meenakshisundaram G. Suresh R. K. Fernando K. Jenny R. Sachidanandham K. Jayaraman 《Applied microbiology and biotechnology》1997,47(5):554-559
A chemically defined medium has been developed to support the growth and the production of mosquito larvicidal factor(s)
(MLF) of Bacillus sphaericus 1593M. On the basis of the data of steady-state continuous cultures, it has been understood that acetate can serve as a sole
carbon and energy source for B. sphaericus 1593M. Utilization of acetate by B. sphaer-icus 1593M and the production of MLF are further enhanced by the addition of glutamate at low concentrations, both in steady-state
continuous as well as in total-cell-retention cultures (TCRC). A two-step TCRC procedure resulted in better biomass and MLF
production by B. sphaericus 1593M. It was also found that glutamate can serve as a carbon source as well as a growth factor in the presence of acetate
and hence is a partially substitutable carbon source.
Received: 3 January 1997 / Accepted: 31 January 1997 相似文献
116.
S. D. Jayaraman S. Ismail N. K. Nair V. Navaratnam 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,690(1-2):253-257
A method is described for the determination of pyronaridine in plasma using high-performance liquid chromatography with fluorescence detection. The method involves liquid-liquid extraction with phosphate buffer (pH 6.0, 0.05 M) and diethyl ether-hexane (70:30%, v/v) and chromatographic separation on a C18 column (Nucleosil, 250 × 4.6 mm I.D., 5 μm particle size) with acetonitrile-0.05 M phosphate buffer pH 6.0 (60:40%, v/v) as the mobile phase (1 ml/min) and detection by fluorescence (λex = 267 nm, λem = 443 nm). The detector response is linear up to 1000 ng and the overall recoveries pyronaridine and quinine were 90.0 and 60.3%, respectively. The assay procedure was adequately sensitive to measure 10 ng/ml pyronaridine in plasma samples with acceptable precision (< 15% C.V.). The method was found to be suitable for use in clinical pharmacological studies. 相似文献
117.
S. George M. Chellapandian B. Sivasankar K. Jayaraman 《Bioprocess and biosystems engineering》1997,16(2):83-85
A method is reported for the treatment of industrial fertilizer effluent rich in urea by a new coupling method to immobilize crude urease onto polyester which is having high flow through property in columns. Kinetics of the immobilized enzyme is established in small column. A typical treatment process with two larger columns in packed bed mode is discussed with and without recycling the treated effluent. 相似文献
118.
The activities of delta-aminolaevulate synthetase and delta-aminolaevulate dehydratase have been assayed in Saccharomyces cerevisiae during glucose repression and de-repression. delta-Aminolaevulate dehydratase increased concomitantly with the increase in oxygen uptake during the de-repression phase caused by the depletion of glucose in the medium. delta-Aminolaevulate synthetase showed an oscillatory behaviour and a spurt in its activity always preceded the increase in oxygen uptake. The activity of both the enzymes was lowered if the cells were incubated with glucose or cycloheximide, but not with chloramphenicol. 相似文献
119.
R. K. Selvakesavan N. N. Dhanya P. Thushara S. M. Abraham R. S. C. Jayaraj A. Balasubramanian B. Deeparaj S. Sudha K. S. Sowmiya Rani V. K. W. Bachpai D. Ganesh N. Diagne L. Laplaze H. Gherbi S. Svistoonoff V. Hocher C. Franche D. Bogusz M. Nambiar-Veetil 《Symbiosis (Philadelphia, Pa.)》2016,70(1-3):117-127
120.
Binding of protein to a phospholipid surface is commonly mediated by amphipathic alpha-helices. To understand the role of alpha-helical structure in protein-lipid interactions, we used discoidal lipoproteins reconstituted from dimyristoylphosphatidylcholine (DMPC) and human apolipoprotein C-I (apoC-I, 6 kDa) or its mutants containing single Pro substitutions along the sequence and differing in their alpha-helical content in solution (0-48%) and on DMPC (40-75%). Thermal denaturation revealed that lipoprotein stability correlates weakly with the protein helix content: proteins with higher alpha-helical content on DMPC may form more stable complexes. Lipoprotein reconstitution upon cooling from the heat-denatured state and DMPC clearance studies revealed that protein secondary structure in solution and on DMPC correlates strongly with the maximal temperature of lipoprotein reconstitution: more helical proteins can reconstitute lipoproteins at higher temperatures. Interestingly, at Tc = 24 degrees C of the DMPC gel-to-liquid crystal transition, the clearance rate is independent of the protein helical content. Consequently, if the packing defects at the phospholipid surface are readily available (e.g., at the lipid phase boundary), insertion of protein into these defects is independent of the secondary structure in solution. However, if hydrophobic defects are limited, protein binding and insertion are aided by other surface-bound proteins and depend on their helical propensity: the larger the propensity, the faster the binding and the broader its temperature range. This positive cooperativity in binding of alpha-helices to phospholipid surface, which may result from direct and/or lipid-mediated protein-protein interactions, may be important for lipoprotein metabolism and for protein-membrane binding. 相似文献