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L E Perez M J Fenton I P Callard 《Comparative biochemistry and physiology. B, Comparative biochemistry》1991,100(4):821-826
1. To determine if a relationship exists between vertebrate vitellogenins and mammalian plasma proteins the EMBL and NBRF computer databases were searched with two partial amino acid sequences from Xenopus laevis and Gallus gallus vitellogenin. 2. A significant relationship was found between vitellogenin and human apolipoprotein B-100 genes, and confirmed using homology-determination programs. 3. Further analysis shows that unique multiple proline consensus regions found in apolipoprotein B-100 are significantly similar to proline dominant regions in vitellogenin. 4. This work suggests that these proteins are functionally and structurally related and should be categorized as a functional group of hepatic lipid transport and metabolism proteins. 相似文献
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Chamitha J. Weeramange Max S. Fairlamb Dipika Singh Aron W. Fenton Liskin Swint‐Kruse 《Protein science : a publication of the Protein Society》2020,29(4):1004-1020
Every method used to quantify biomolecular interactions has its own strengths and limitations. To quantify protein‐DNA binding affinities, nitrocellulose filter binding assays with 32P‐labeled DNA quantify Kd values from 10?12 to 10?8 M but have several technical limitations. Here, we considered the suitability of biolayer interferometry (BLI), which monitors association and dissociation of a soluble macromolecule to an immobilized species; the ratio koff/kon determines Kd. However, for lactose repressor protein (LacI) and an engineered repressor protein (“LLhF”) binding immobilized DNA, complicated kinetic curves precluded this analysis. Thus, we determined whether the amplitude of the BLI signal at equilibrium related linearly to the fraction of protein bound to DNA. A key question was the effective concentration of immobilized DNA. Equilibrium titration experiments with DNA concentrations below Kd (equilibrium binding regime) must be analyzed differently than those with DNA near or above Kd (stoichiometric binding regime). For ForteBio streptavidin tips, the most frequent effective DNA concentration was ~2 × 10?9 M. Although variation occurred among different lots of sensor tips, binding events with Kd ≥ 10?8 M should reliably be in the equilibrium binding regime. We also observed effects from multi‐valent interactions: Tetrameric LacI bound two immobilized DNAs whereas dimeric LLhF did not. We next used BLI to quantify the amount of inducer sugars required to allosterically diminish protein‐DNA binding and to assess the affinity of fructose‐1‐kinase for the DNA‐LLhF complex. Overall, when experimental design corresponded with appropriate data interpretation, BLI was convenient and reliable for monitoring equilibrium titrations and thereby quantifying a variety of binding interactions. 相似文献
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A fluorescence video imaging system utilizing relatively inexpensive commercial components is described. The instrument utilizes a black and white CCD video camera detector, a commercial video imaging board and a IBM-AT compatible computer. The color output of the imaging board greatly aids in the users ability to visually discriminate areas of interest in the video field. Software development that enables the user to capture kinetic traces in real time from the video images is also described. The system is used to monitor fluorescence from photosynthetic systems. The usefulness of the system in screening for photosynthetic mutants is also demonstrated. The cost of the system can be kept below $12,000.Abbreviations CCD
charge-coupled device
- DCMU
diuron, 3-[3,4-Dichlorophenyl]1,1-dimethylurea
- AGC
automatic gain control
- LUT
look-up table
- AOI
area of interest
- CPU
central processing unit
- RAM
random access memory
- ADC
analog-to-digital converter
- FVIPS
fluorescence video image processing software
- I/O
input/output
- F0
dark-level fluorescence
- OIDPSMT
characteristic transient components, where O is dark level, I is intermediary peak, D is dip, P is peak of fast transient, S is quasi-steady state level, M is second maximum, T is terminal level 相似文献
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D. Nicol K. F. Armstrong S. D. Wratten C. M. Cameron C. Frampton & B. Fenton 《Molecular ecology》1997,6(3):255-265
RAPD-PCR was used to determine the genetic variation of Metopolophium dirhodum collected in a winter wheat field and in a nearby 2.5-m-high suction trap at Lincoln, New Zealand. Over three collection dates, five distinct genotypes were identified, using two primers (OPK16 and OPC09) independently. There was a significant temporal effect on the ratio of genotypes in populations collected in the field. There was no significant spatial aggregation or association of these genotypes in the field. Two of the genotypes present in the field were also detected in the suction trap sample. Using a higher resolution method of RAPD-PCR (with the Stoffel fragment of Taq polymerase), a total of 124 genotypes were distinguished from 142 individuals collected from Scotland and New Zealand. The Jaccard similarity index ( S ) was used to measure similarity between individual aphids within and between populations from both hemispheres. All populations were very diverse ( S < 0.33). However, at similar crop growth stages, M. dirhodum was significantly more diverse in Scotland than in New Zealand. The results are discussed in relation to the value of monitoring aphid flights for pest forecasting, and in terms of the most appropriate RAPD-PCR techniques. 相似文献