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61.
Release of Excitatory Amino Acids from Cultured Hippocampal Astrocytes Induced by a Hypoxic-Hypoglycemic Stimulation 总被引:2,自引:0,他引:2
Tadanori Ogata† Yoichi Nakamura Taiho Shibata† Kiyoshi Kataoka 《Journal of neurochemistry》1992,58(5):1957-1959
An excess release of excitatory amino acids (EAA) is an important factor for postischemic brain damage. In the present communication, we demonstrate that cultured hippocampal cells release EAA after hypoxic-hypoglycemic treatment. The amounts of EAA released from astrocytes were appreciably above those released from neurons. Furthermore, the amount of aspartate released from astrocytes was comparable to that of glutamate, although the endogenous content of aspartate was one-fifth that of glutamate. The endogenous content of aspartate in astrocytes increased even after hypoxic-hypoglycemic treatment. These results suggests that ischemic neuronal death is due, at least in part, to the excitotoxicity of aspartate and glutamate derived from surrounding astrocytes. 相似文献
62.
Continuous butanol/isopropanol fermentation in down-flow column reactor coupled with pervaporation using supported liquid membrane 总被引:2,自引:0,他引:2
Continuous butanol/isopropanol fermentation with immobilized Clostridium isopropylicum was performed in a downflow column reactor using molasses as the substrate. In order to prevent product inhibition and at the same time obtain high concentration of the products, the column reactor was coupled with a pervaporation module using a supported liquid membrane. The liquid membrane was prepared with oleyl alcohol nontoxic to the microorganism. In comparison with the continuous fermentation without product removal, the specific butanol production rate was 2 times higher. The butanol concentration in the permeate was 230 kg/m(3), which was about 50 times higher than that in the culture broth. A numerical investigation suggested a further increase in the productivity by improving the module construction. 相似文献
63.
S Shimizu M Kataoka K Shimizu M Hirakata K Sakamoto H Yamada 《European journal of biochemistry》1992,209(1):383-390
A novel lactonohydrolase, an enzyme that catalyzes the hydrolysis of aldonate lactones to the corresponding aldonic acids, was purified 10-fold to apparent homogeneity, with a 61% overall recovery, from Fusarium oxysporum AKU 3702, through a purification procedure comprising DEAE-Sephacel, octyl-Sepharose CL-4B and hydroxyapatite chromatographies and crystallization. The molecular mass of the native enzyme, as estimated by high-performance gel-permeation chromatography, is 125 kDa, and the subunit molecular mass is 60 kDa. The enzyme contains 15.4% (by mass) glucose equivalent of carbohydrate, and about 1 mol calcium/subunit. The enzyme hydrolyzes aldonate lactones, such as D-galactono-gamma-lactone and L-mannono-gamma-lactone, stereospecifically. Furthermore, it can catalyze the asymmetric hydrolysis of D-pantoyl lactone, which is a promising chiral building block for the chemical synthesis of D-pantothenate. These reactions are reversible, and the reaction equilibrium at pH 6.0 has a molar ratio of nearly 1:1 with D-pantoyl lactone and D-pantoic acid. The Km and Vmax for D-galactono-gamma-lactone are 3.6 mM and 1440 U/mg, respectively, and those for D-galactonate are 52.6 mM and 216 U/mg, respectively. The enzyme also irreversibly hydrolyzes several aromatic lactones, such as dihydrocoumarin and homogentisic-acid lactone. 相似文献
64.
S Yamamoto T Yamamoto T Kataoka E Kuramoto O Yano T Tokunaga 《Journal of immunology (Baltimore, Md. : 1950)》1992,148(12):4072-4076
Thirty-mer single-stranded oligonucleotides, with a sequence chosen from the known cDNA encoding the 64-kDa protein named Ag A or the MPB-70 protein of Mycobacterium bovis BCG and the human cellular proteins such as complement component 1 inhibitor and Ig rearranged lambda-chain, were used to dissect the capability to induce IFN and to augment NK cell activity of mouse spleen cells by coincubation in vitro. Three with the hexamer palindromic sequence as GACGTC were active, whereas two kinds of oligonucleotides with no palindrome were inactive. The oligonucleotides containing at least one of the different palindromic sequences showed no activity. When a portion of the sequence of the inactive oligonucleotides was substituted with either palindromic sequence of GACGTC, AGCGCT, or AACGTT, the oligonucleotide acquired the ability to augment NK activity. In contrast, the oligonucleotides substituted with another palindromic sequence such as ACCGGT was without effect. Furthermore, exchange of two neighboring mononucleotides within, but not outside, the active palindromic sequence destroyed the ability of the oligonucleotides to augment NK cell activity. Stimulation of spleen cells with the substituted oligonucleotide, A4a-AAC, induced production of significant amounts of IFN-alpha/beta and small amounts of IFN-gamma. Augmentation of NK activity of the cells by the oligonucleotide was ascribed to IFN-alpha/beta production. These results strongly suggest that the presence of the unique palindromic sequences, such as GACGTC, AGCGCT, and AACGTT, but not ACCGGT, is essential for the immunostimulatory activity of oligonucleotides. 相似文献
65.
Adenine depurination and inactivation of plant ribosomes by an antiviral protein of Mirabilis jalapa (MAP) 总被引:4,自引:0,他引:4
Jiro Kataoka Noriyuki Habuka Masashi Miyano Chikara Masuta Akira Koiwai 《Plant molecular biology》1992,20(6):1111-1119
Mirabilis antiviral protein (MAP) is a single-chain ribosome-inactivating protein (RIP) isolated from Mirabilis jalapa L. It depurinates the 28S-like rRNAs of prokaryotes and eukaryotes. A specific modification in the 25S rRNA of M. jalapa was found to occur during isolation of ribosomes by polyacrylamide/agarose composite gel electrophoresis. Primer extension analysis revealed the modification site to be at the adenine residue corresponding to A4324 in rat 28S rRNA. The amount of endogenous MAP seemed to be sufficient to inactivate most of the homologous ribosomes. The adenine of wheat ribosomes was also found to be removed to some extent by an endogenous RIP (tritin). However, the amount of endogenous tritin seemed to be insufficient for quantitative depurination of the homologous ribosomes.Endogenous MAP could shut down the protein synthesis of its own cells when it spreads into the cytoplasm through breaks of the cells. Therefore, we speculate that MAP is a defensive agent to induce viral resistance through the suicide of its own cells. 相似文献
66.
Masamitsu Honma Eiko Kataoka Kiyokata Ohnishi Tadao Ohno Masao Takeuchi Nobuo Nomura Hiroshi Mizusawa 《In vitro cellular & developmental biology. Animal》1992,28(1):24-28
Summary Using the polymorphic DNA probes, ChdTC-15, ChdTC-114, pYNH24, and λTM-18, a DNA profiling system was developed that verified
identities of individual cultured cell lines collected in the Japanese cell banks, JCRB, RCB, and IFO. These highly polymorphic
DNA probes include both VNTR (Variable Number of Tandem Repeats) sequences and substantial lengths of unique regions. In the
mixed probe system, several distinct bands from four to eight can be used for cell line identification. These bands were widely
spread in a range of molecular sizes, and were stable and reproducible under stringent conditions of Southern blot hybridization.
Because the DNA profile was specific for each individual human cell line, it is useful not only to authenticate many existing
cultured cell lines but also to monitor their identity during propagation in a laboratory, and to confirm newly established
lines as unique. 相似文献
67.
Tomio Takamatsu Kasuhiko Yamazaki Masanori Kayano 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1992,584(2):261-266
A gas chromatographic—mass spectrometric method was developed to determine eperisone hydrochloride, 4′-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride, in human plasma over the concentration range 0.2–40 ng/ml. Excellent sensitivity was achieved by selection of a favorable fragment ion, m/z 98, of eperisone and reduction of heat decomposition of eperisone by using a splitless injector and a shortened capillary column. The method described here allows the determination of plasma concentrations as low as 0.2 ng/ml, the concentration attained 6 h after a single oral administration of 50 mg. At eperisone hydrochloride concentrations higher than 0.5 ng/ml, the mean inter-day variation of accuracy of the assay was less than 12%. 相似文献
68.
T Kataoka S Yamamoto T Yamamoto T Tokunaga 《Japanese journal of medical science & biology》1990,43(5):171-182
In vivo antitumor activity of a deoxyribonucleic acid fraction obtained from Mycobacterium bovis BCG (named MY-1) increased when it was complexed with poly-L-lysine (poly LL) solubilized by addition of carboxymethylcellulose (CMC). The complex of MY-1 and poly LL/CMC induced interferon in vivo at a low dose of MY-1 which alone exerted no IFN induction. With Line 10 hepatoma (L10) which is syngeneic with strain 2 guinea pigs, it was demonstrated that repeated intralesional injections of the complex resulted in delay of tumor growth and complete cure of animals from L10 tumor inoculated. Similar treatment of the animals with the same amount of MY-1 or poly LL/CMC alone had little therapeutic effect on the tumor growth. 相似文献
69.
Stereospecific Reduction of Ethyl 2′ -Ketopantothenate to Ethyl D-(+)-Pantothenate with Microbial Cells as a Catalyst
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Michihiko Kataoka Sakayu Shimizu Yukiko Doi Hideaki Yamada 《Applied microbiology》1990,56(11):3595-3597
A novel enzymatic process for the synthesis of D-(+)-pantothenic acid through the asymmetric reduction of the 2′ -ketopantothenate ester is described. Candida macedoniensis AKU 4588 was found to convert ethyl 2′ -ketopantothenate (80 mg/ml) almost specifically to ethyl D-(+)-pantothenate (>98% enantiomeric excess), with a molar yield of 97.2%. 相似文献
70.
Shigeo Yamamoto Miki Yokogawa Kyomi Wakamatsu Hiroyuki Kataoka Masami Makita 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,233(1):29-38
A gas chromatographic method was developed for the determination of monoacetylputrescine, monoacetylcadaverine, N1-acetylspermidine and N5-acetylspermidine in human urine. The amines were isolated from urine by silica gel column chromatography. 1, 10-Diaminodecane was used as internal standard. The amines were reacted with ethyl chloroformate in aqueous medium to four ethyloxycarbonyl derivatives prior to application to gas chromatography using a flame ionization detector. Separation and determination of the derivatives were carried out on a Uniport HP column (1.0 m) impregnated with 0.5% SP-1000 under temperature-programmed conditions. The monoacetylpolyamines could be measured accurately at the nanomole level. The method was used for the determination of the monoacetylpolyamines in urine of healthy volunteers. The values obtained were in the range of the published data. 相似文献