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1.
Recently we demonstrated that ethidium bromide altered the plasma and subcellular membrane glycoproteins in control and virus transformed cells. It is reported here that ethidium bromide also stimulated the membrane associated process of sugar transport. The Km of the virus transformed cells and the ethidium bromide treated cells is the same as that of the control cells while the maximum velocity as compared to the control cells is significantly increased. The transport of 2-deoxy-D-glucose was inhibited by glucose, cytochalasin B and neuraminidase but was unaffected by variations in cell density or pH of the incubation medium. 相似文献
2.
Ethylene production of habituated and auxin-requiring tobacco ( Nicotiana tabacum L. cv. Xanthi) callus cultures were compared. More ethylene was produced by auxinrequiring i.e. auxin-heterotrophic cultures than by habituated ones. Treatment with 2,4-dichlorophenoxyacetic acid increased the ethylene evolution of habituated cultures over the range 10−7 to 10−4 M , which suggests that the higher ethylene production of auxin-dependent callus is caused by the 2,4-D in the medium. The IAA levels depended on the age of both types of callus cultures. 相似文献
3.
Summary Carboxyl groups present on the outer face of the hexagonally ordered S-layer lattices from Bacillus stearothermophilus PV72 and Clostridium thermohydrosulfuricum L111-69 were activated with carbodiimide. The reaction of the activated carboxyl groups with free amino groups of low molecular weight nucleophiles was controlled by labelling with polycationized ferritin, a net positively charged topographical marker for electron microscopy, which densely binds to S-layers possessing free carboxyl groups. Carbodiimide-activated carboxyl groups were also allowed to react with amino groups of ferritin (MW 440 000) and invertase (MW 270 000). Covalent attachment of ferritin was examined by electron microscopy. Using invertase, approximately 1 mg enzyme was bound per mg S-layer protein indicating a high packing density of invertase molecules on the outer face of the S-layer lattice. The immobilized invertase retained 70% of its original activity. 相似文献
4.
Regeneration of transgenic plants of Prunus armeniaca containing the coat protein gene of Plum Pox Virus 总被引:1,自引:0,他引:1
Margit Laimer da Câmara Machado Artur da Câmara Machado Veronika Hanzer Hans Weiss Ferdinand Regner Herta Steinkellner Diethard Mattanovich Regina Plail Elisabeth Knapp Birgit Kalthoff Hermann Katinger 《Plant cell reports》1992,11(1):25-29
Summary A system was developed which allows the transfer of foreign genes into apricot cultivars. We report the transformation and regeneration of Prunus armeniaca plants with Agrobacterium tumefaciens strain LBA 4404 containing various binary plasmids, pBinGUSint, carrying the marker gene ß-glucuronidase (GUS) and pBinPPVm, carrying the coat protein gene of Plum Pox Virus (PPV). The marker gene GUS was used for optical evaluation of the efficiency of the transformation system. The coat protein gene of PPV was used to introduce coat protein mediated resistance against one of the most important pathogens of stone fruit trees in Europe and the whole Mediterranean area. This is the first report of the successful integration of a viral coat protein gene into a fruit tree species, opening a new perspective on the control of the disease.Abbreviations GUS
ß-glucuronidase
- PPV
Plum Pox Virus
- BA
6-benzylaminopurine
- NPTII
neomycin phosphotransferase II
- CP
coat protein
- CaMV
Cauliflower Mosaic Virus
- P35S 35S
promoter
- MS
Murashige and Skoog
- PCR
polymerase chain reaction
- P/C/I
phenol/chloroform/isoamylalcohol
- RNase
ribonuclease
- dNTP
deoxyribonucleosidetriphosphate
- DMSO
dimethyl sulfoxide 相似文献
5.
Anthraquinones produced by suspension cultures of Galium vernum are completely retained intracellularly. Surprisingly, in the presence of some polymeric adsorbents anthraquinones are partially released into the culture medium. The secretion and in situ removal stimulates anthraquinone production in cell cultures of Galium vernum. Best results were obtained with Wofatit ES and Amberlite XAD-2.Abbreviations DW
dry weight
- MS
Murashige & Skoog[7]medium
- NAA
1-naphthaleneacetic acid 相似文献
6.
Anna Pugatshova ülle Kikas Margit Prüssel Aivo Reinart Eduard Tamm et al. 《Plant Growth Regulation》1991,10(2):177-178
Book Review
Principles of environmental physicsJ.L. Monteith and M.H. Unsworth Second edition. London: Edward Arnold, 1990. xii + 291 pages. £30.00 (hardback), £14.95 (paperback). ISBN 0-7131-2931-X 相似文献7.
Summary To provide a hitherto lacking review which focuses on gill surface area of freshwater fish, we collected and analysed morphometric data from the literature. The scaling exponent of gill area ranges from 0.36 to 1.13, with a mean value of 0.76. The absolute values for the largest gill areas are about 5 times as high as those of the smallest. This range resembles that of marine fish, if specially adapted steady swimmers, such as tunnies and some sharks, are excluded. Generally it appears that the gill areas of freshwater fish are smaller than those of comparable marine species. To establish whether a relationship exists between gill area and swimming activity or oxygen content of water, the activity of each species and the oxygen content of its habitat were estimated and checked against the gill area. ANOVA revealed that activity explains the presence of the smallest gill areas only, while oxygen content does not correlate with gill area at all. The morphometric variables determining gill area (total length of filaments, average lamellar density, average lamellar area) are highly correlated; total gill area correlates mainly with lamellar density and to a lesser degree with filament length; lamellar area varies independently. Different populations of the same species exhibit striking differences with respect to gill areas, total length of filaments, average lamellar density and average lamellar area. These differences point to a substantial morphological plasticity of the gill system. 相似文献
8.
Bärbel Hahn-Hägerdal Sissi Berner Kerstin Skoog 《Applied microbiology and biotechnology》1986,24(4):287-293
Summary Ethanol was produced from xylose, using the enzyme glucose isomerase (xylose isomerase) and Saccharomyces cerevisiae. The influence of aeration, pH, enzyme concentration, cell mass and the concentration of the respiratory inhibitor sodium azide on the production of ethanol and the formation of by-products was investigated. Anaerobic conditions at pH 6.0, 10 g/l enzyme, 75 g/l dry weight cell mass and 4.6 mM sodium azide were found to be optimal. Under these conditions theoretical yields of ethanol were obtained from 42 g/l xylose within 24 hours.In a fed-batch culture, 62 g/l ethanol was produced from 127 g/l xylose with a yield of 0.49 and a productivity of 1.35 g/l·h. 相似文献
9.
Structural and chemical characterization of S-layers of selected strains ofBacillus stearothermophilus andDesulfotomaculum nigrificans 总被引:13,自引:0,他引:13
The structures, amino acid- and neutral sugar compositions of the crystalline surface layers (S-layers) of four selected strains each ofBacillus stearothermophilus andDesulfotomaculum nigrificans were compared. Among the four strains of each species a remarkable diversity in the molecular weights of the S-layer subunits and in the geometry and constants of the S-layer lattices was apparent. The crystalline arrays included hexagonal (p6), square (p4) and oblique (p2) lattices. In vitro self-assembly of isolated S-layer subunits (or S-layer fragments) led to the formation of flat sheets or open-ended cylindrical assembly products. The amino acid composition of the S-layers exhibited great similarities and was predominantly acidic. With the exception of the S-layers of two strains ofB. stearothermophilus (where only traces of neutral sugars could be detected), all other S-layer proteins seemed to be glycosylated. Among these strains significant differences in the amount and composition of the glycan portions were found. Based on this diversity interesting questions may be asked about the biological significance of the carbohydrate units of glycoproteins in prokaryotic organisms. 相似文献
10.
Identification of baculovirus gene that promotes Autographa californica nuclear polyhedrosis virus replication in a nonpermissive insect cell line. 总被引:5,自引:3,他引:2 下载免费PDF全文
A gene that promotes Autographa californica M nuclear polyhedrosis virus (AcMNPV) replication in IPLB-Ld652Y cells, a cell line that is nonpermissive for AcMNPV, was identified in Lymantria dispar M nuclear polyhedrosis virus (LdMNPV). Cotransfection of AcMNPV DNA and a plasmid carrying the LdMNPV gene into IPLB-Ld652Y cells results in AcMNPV replication. The gene maps between 43.3 and 43.8 map units on the 162-kbp genome of LdMNPV. It comprises a 218-codon open reading frame and encodes a polypeptide with a predicted molecular mass of 25.7 kDa. The predicted polypeptide is glutamic acid and valine rich and negatively charged, with a pI of 4.61. No protein sequence motifs were identified, and no matches with known nucleotide or peptide sequences were found in the AcMNPV genome or database searches that suggest how this gene might function. A recombinant AcMNPV bearing the LdMNPV gene overcomes a block in protein synthesis observed in AcMNPV-infected IPLB-Ld652Y cells. Using Southern blotting techniques, we were unable to identify a homolog in Orgyia pseudotsugata M nuclear polyhedrosis virus, a baculovirus that is routinely propagated in IPLB-Ld652Y cells. This suggests that the LdMNPV host range is unique among the baculoviruses studied to date. We named this gene hrf-1 (for host range factor 1). 相似文献