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51.
52.
Rudrapatnam N. Tharanathan Akira Yokota Heike Rau Hubert Mayer 《Archives of microbiology》1993,159(5):445-452
Lipopolysaccharides (LPS), isolated from four Mycoplana species, i.e. the type strains of M. bullata, M. segnis, M. ramosa and M. dimorpha, were characterized onto their chemical composition and their respective lipid A-types. Those of M. bullata and M. segnis showed on DOC-PAGE an R-type character and had lipid A's of the Lipid ADAG-type which exclusively contained 2,3-diamino-2,3-dideoxy-d-glucose as lipid A sugar. LPS's of M. ramosa and M. dimorpha showed, although only weakly expressed, ladder-like patterns on DOC-PAGE indicating some S-type LPS's and lipid A of the d-glucosamine type (Lipid AGlcN). M. bullata LPS contained mannose and glucose in major amounts and additionally l-glycero-d-mannoheptose, whereas M. segnis LPS was composed of rhamnose, mannose and glucose together with both, d-glycero-d-manno- and l-glycero-d-manno-heptoses in a molar ratio of 1:2. All LPS's contained 2-keto-3-deoxy-octonic acid (Kdo), phosphate and an unidentified acidic component X. In addition to X, M. segnis LPS contained glucuronic and galacturonic acids, whereas M. ramosa LPS contained only galacturonic acid. Acetic acid hydrolysis of the LPS resulted in splitting off lipid A moieties, very rich in 3-hydroxy fatty acids, in particular in 3-OH-12:0 (in Lipid ADAG), or in 3-OH-14:0 (in Lipid AGlcN). Analysis of the 3-acyloxyacyl residues revealed major amounts of amide-linked 3-OH(3-OH-13:0)12:0 in lipid A of M. bullata and 3-OH(12:0)12:0 in lipid A of M. segnis. The rare 4-oxo-myristic acid (4-oxo-14:0) was observed only in M. bullata LPS, where it is ester-linked. Amide linked diesters could not be traced in M. ramosa and M. dimorpha. All four lipid A's lacked erster-bound acyloxyacyl residues.Non-standard abbreviations DAG
2,3-diamino-2,3-dideoxy-d-glucose
- Kdo
2-keto-3-deoxy-octonate
- LPS
lipopolysaccharide
- PITC
phenyl isothiocyanate
- NANA
N-acetyl neuraminic acid 相似文献
53.
Teruyo Ito Keiichi Hiramatsu Yoshihiro Ohshita Takeshi Yokota 《Microbiology and immunology》1993,37(4):281-288
In cultures of Vibrio cholerae strains of Ogawa serotype, variant strains which had undergone serotype conversion from Ogawa to Inaba were identified. The rfbT genes cloned from the parent strains were found to produce a 31-kDa protein in the maxicell system, and to cause serotype conversion when introduced into E. coli cells expressing Inaba serotype specificity. On the other hand, rfbT genes cloned from the variant strains neither produced the 31-kDa protein nor caused serotype conversion. Nucleotide sequence of these rfbT genes as well as those of two clinical Vibrio cholerae strains of Inaba serotype revealed that mutations causing premature termination of their rfbT genes were invariably present in strains expressing Inaba serotype specificity. The result strongly suggested that genetic alteration of the rfbT gene is responsible for serotype conversion of Vibrio cholerae O1. 相似文献
54.
Hiroyuki Suzuki Shozo Fujioka Suguru Takatsuto Takao Yokota Noboru Murofushi Akira Sakurai 《Journal of Plant Growth Regulation》1993,12(2):101-106
Feeding experiments with tritium- and deuterium-labeled castasterone (CS) were conducted with three cell lines of Catharanthus roseus, including crown gall cells and nontransformed cells. In all three cell lines, the conversion of CS to brassinolide (BL) was observed and unequivocally confirmed by gas chromatography/mass spectrometry (GC/MS). This is the first conclusive evidence that CS is the biosynthetic precursor of BL.Biosynthesis of brassinosteroids in Catharanthus roseus. Part II. Part I of this series: Yokota et al. (1990a). 相似文献
55.
56.
Anwaruzzaman ; Sawada Shinichi; Usuda Hideaki; Yokota Akiho 《Plant & cell physiology》1995,36(3):425-433
The mechanism of the regulation of the activation of ribulose1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) by inorganicphosphate (Pi) in the presence of limiting concentrations ofCO2 was explored. The activation state of RuBisCO increasedsigmoidally following a biphasic kinetics against the concentrationof Pi in the activation mixture with an intermediary plateauat 2 to 3 mM Pi when the enzyme was activated for 30 min. Theintermediary plateau could not be seen when the preincubationtime was 10 min and the activation was completed at 10 mM Pi.RuBisCO from Euglena also showed a quite similar activationkinetics. The activation was not due to the contaminating CO2included in the stock Pi solution or in the activation buffercontaining the enzyme. The experiments with 2-carboxyarabinitol1,5-bisphosphate showed that the Pi stimulated activation wasdue to the promotion of binding of the activator CO2 to theactivation sites. It was also found that Pi increased the affinityof RuBisCO for the activator CO2 5.4-fold accompanied by a decreaseof the half-saturating concentration of CO2 to 1.6 µMat 20 mM MgCl2. Physiological significance of the effects ofPi on the activation of RuBisCO is discussed.
2Present address: Laboratory of Plant Molecular Physiology,Research Institute of Innovative Technology for the Earth (RITE),9-2 Kizugawadai, Kizu-cho, Soraku-gun, Kyoto, Japan. 相似文献
57.
Localization of the B of L-hydroxyacid oxidase (HOX-B) in monkey kidney peroxisomes was investigated by immunoelectron microscopic techniques. Kidneys of Japanese monkeys,Macaca fuscata, were fixed with 4% paraformaldehyde+0.25% glutaraldehyde and embedded in LR White resin. Thin sections were stained for HOX-B and catalase by the immunogold technique. HOX-B was localized in the marginal plates of normal peroxisomes and the dense bar of dumb-bellshaped peroxisomes. Catalase was detected in the matrix of normal peroxisomes and in the terminal dilatations of dumb-bell-shaped peroxisomes. There were no gold particles indicating presence of catalase associated with the marginal plates or with the dense bars. Immunoblot analysis of monkey kidney homogenate showed that HOX-B has a molecular mass of 42 kDa that was slightly larger than that of rat kidney HOX-B (39 kDa). The results show that the dense bar of dumb-bell-shaped peroxisomes in monkey kidney is composed of at least HOX-B and is a variation of the marginal plates. 相似文献
58.
Evolution and structure of two ADP-ribosylation enterotoxins, Escherichia coli heat-labile toxin and cholera toxin 总被引:19,自引:0,他引:19
Nucleotide sequence comparisons of the heat-labile enterotoxin (LTh) genes of E. coli pathogenic for humans with cholera toxin (CT) genes suggest that the two toxin genes have evolved from a common ancestry by a series of single base changes, while conserving the catalytic fragment A1 (ADP-ribose transferase). Based on the local hydrophilicity profiles of LTh and CT peptides, a transmembrane segment appears to be present in A1 in both toxins. 相似文献
59.
Summary Ultrastructural localization of three mitochondrial β-oxidation enzymes, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase,
and 3-ketoacyl-CoA thiolase in rat liver was studied by a post-embedding immunocytochemical technique. Rat liver was fixed
by perfusion. Vibratome sections (100 μm thick) were embedded in Lowicryl K4M. Ultrathin sections were separately incubated
with antibody to each enzyme, followed by protein A-gold complex. Gold particles representing the antigenic sites for all
enzymes examined were confined exclusively to mitochondria of hepatocytes and other sinus-lining cells. Peroxisomes were consistently
negative for the immunolabelling. In the mitochondria the gold particles were localized in the matrical side of inner membrane.
The control experiments confirmed the specificity of the immunolabelling. The results firstly indicate that the mitochondrial
β-oxidation enzymes are present in the matrix of mitochondria and associated with the inner membrane. 相似文献
60.