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991.
James Epstein Edward J. Desjardins Peter L. Hudson Patricia K. Donahoe 《In vitro cellular & developmental biology. Plant》1989,25(2):213-216
Summary Stainless steel mesh supported the high density growth of anchorage dependent CHO fibroblasts without the use of a special
culture system. CHO cells, designated B-9, containing an amplified genomic construct of the human gene for Mullerian Inhibiting
Substance (MIS), grew to a high confluent density on stainless steel meshwork while producing substantial amounts of human
recombinant MIS over a long period of time. The mesh could be easily coated with various extracellular matrix proteins, such
as Laminin, Fibronectin, Collagen or Matrigel, which permitted the testing of the effects of surface modifications on cell
yield and recombinant protein production. Since the amount of medium per surface area required for optimal cell growth is
lower than for some large volume cell culture methods, media costs can be reduced using mesh. In addition, no special cell
culture equipment or complex manipulations are required. Thus, the use of meshwork for anchorage-dependent cells can increase
the efficiency of growth and decrease the cost of recombinant protein production.
This work is supported by NIH grant CA 17393 and American Cancer Society grant PDT 221A to P. K. D. and NIH grant EY 06535
to J. E.
Editor's Statement This approach to large scale, high density cultivation of cells, one of several which are based on increasing
surface area of the cultures, allows the production of large amounts of recombinant product within a research laboratory with
modest bulk culture capability. 相似文献
992.
Err-Cheng Chan Peter P. Ueng Karri L. Eder Li Fu Chen 《Journal of industrial microbiology & biotechnology》1989,4(6):409-417
Summary The xyclose isomerase gene inEscherichia coli was cloned complementarily into a Leu2-negativeSchizosaccharomyces pombe mutant (ATCC 38399). The subsequent integration of the plasmid into the chromosomal DNA of the host yeast was verified by using the dot blot and southern blot techniques. The expressed xylose isomerase showed activity on a nondenaturing polyacrylamide gel. The expression of xylose isomerase gene was influenced by the concentration of nutrients in the fermentation broth. The yeast possessed a xylose isomerase activity of 20 nmol/min/mg by growing in an enriched medium containing yeast extract-malt extract-peptone (YMP) andd-xylose. The conversion ofd-xylose tod-xylulose catalyzed by xylose isomerase in the transformed yeast cells makes it possible to fermentd-xylose with ethanol as a major product. When the fermentation broth contained YMP and 5% (w/v)d-xylose, the maximal ethanol yield and productivity reached 0.42 g/g and 0.19 g/l/h, respectively. 相似文献
993.
Robert J. Guttendorf Harry B. Kostenbauder Peter J. Wedlund 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1989,489(2)
A high-performance liquid chromatographic (HPLC) technique is described for quantification of R(+)- and S(−)-propranolol from 100-μl rat blood samples. The procedure involves chiral derivatization with tert.-butoxycarbonyl-
-leucine anhydride to form diastereomeric propranolol-
-leucine derivatives which are separated on a reversed-phase HPLC column. The method as previously reported has been modified for assaying serial blood microsamples obtained from the rat for pharmacokinetic studies. An internal standard, cyclopentyldesisopropylpropranolol, has been incorporated into the assay and several derivatization parameters have been altered. Standard curves for both enantiomers were linear over a 60-fold concentration range in 100-μl samples of whole rat blood (12.5–750 ng/ml; r=0.9992 for each enantiomer). Inter- and intra-assay variability was less than 12% for each enantiomer at 25 ng/ml. No enantiomeric interference or racemization was observed as a result of the derivatization. No analytical interference was noted from endogenous components in rat blood samples. Preliminary data from two male Sprague-Dawley rats given a 2.0 mg/kg intravenous dose of racemic propranolol revealed differential disposition of the two enantiomers. R(+)-Propranolol achieved higher initial concentration but was eliminated more rapidly than S(−)-propranolol. Terminal half-lives of R(+)- and S(−)-propranolol were 19.23 and 51.95 min, respectively, in one rat, and 14.50 and 52.07 min, respectively, in the other. 相似文献
994.
Peter L. Pingerelli Hiroshi Mizukami Monica J. Mooney Alice L. Schlaepfer 《The protein journal》1989,8(2):183-196
S100b is a calcium-binding protein that will bind to many calmodulin target molecules in a Ca2+-dependent manner. In order to study the Ca2+-dependent binding properties of S100b, its interaction with a calmodulin antagonist, trifluoperazine (TFP), was investigated using [19F]- and [1H]-NMR and UV-difference spectroscopy. It was estimated from [19F]-NMR that in the absence of Ca2+, thek 1/2 value of TFP was 130 µM, while itsk 1/2 value decreased to 28 µM in the presence of Ca2+. The addition of KCl was not antagonistic to the Ca2+-dependent interaction of TFP to S100b. The chemical exchange rate of TFP with Ca2+-bound S100b was estimated to be 9×102 sec?1. By comparison with TFP-calmodulin exchange rates, it is suggested that the TFP-binding site on S100b is structurally different from its binding sites on calmodulin. Proton NMR resonance broadening in the range 6.8–7.2 ppm, corresponding to phenylalanine nuclei of S100b, indicates that these residues may be involved in TFP binding. Addition of Ca2+ to a 1:1 mixture of S100b and TFP resulted in a red-shifted UV-difference spectrum, while no significant difference spectrum was detected when Mg2+ was added to a S100b-TFP solution. Thus, we suggest that Ca2+ induces the exposure of a hydrophobic domain on S100b containing one or more phenylalanine residues that will bind TFP but that this domain is different from the hydrophobic domain on calmodulin. 相似文献
995.
996.
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998.
Smeekens Sjef Geerts Dirk Bauerle Cynthia Weisbeek Peter 《Molecular genetics and genomics : MGG》1989,217(1):178-181
Molecular Genetics and Genomics - Plant ferredoxin is a nuclear-encoded chloroplast protein that is synthesized in the cytoplasm as a transit peptide-containing precursor molecule. To identify... 相似文献
999.
1000.