全文获取类型
收费全文 | 273篇 |
免费 | 22篇 |
专业分类
295篇 |
出版年
2017年 | 2篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 13篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 2篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有295条查询结果,搜索用时 15 毫秒
1.
Yusuke Nakamura Michio Ogawa Takahiro Nishide Mitsuru Emi Goro Kosaki Seiichi Himeno Kenichi Matsubara 《Gene》1984,28(2):263-270
The nucleotide sequences of the cloned human salivary and pancreatic α-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5′-noncoding region and 32 in the 3′-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5′- and 3′-noncoding regions, respectively. The nucleotide sequence humology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous.Comparison of the sequences of human α-amylase cDNAs with those previously obtained for mouse α-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human α-amylase. 相似文献
2.
Cloning and nucleotide sequence of the penicillinase antirepressor gene penJ of Bacillus licheniformis. 总被引:9,自引:5,他引:4 下载免费PDF全文
The penicillinase antirepressor gene, penJ, of Bacillus licheniformis ATCC 9945a was cloned in Escherichia coli by using pMB9 as a vector plasmid. The penicillinase gene, penP, its repressor gene, penI, and penJ were encoded on the cloned 5.2-kilobase HindIII fragment of the recombinant plasmid pTTE71. The penJ open reading frame was composed of 1,803 bases and 601 amino acid residues (molecular weight, 68,388). A Shine-Dalgarno sequence was found 7 bases upstream from the translation start site. Since this sequence was located in the 3'-terminal region of the penI gene, penJ might be transcribed together with penI as a polycistronic mRNA from the penI promoter. Frameshift mutations of penJ were constructed in vitro from pTTE71, and the penJ mutant gene was introduced into B. licheniformis by chromosomal recombination. The transformant B. licheniformis U173 (penP+ penI+ penJ) turned out to be uninducible for penicillinase production, whereas the wild-type strain (penP+ penI+ penJ+) was inducible. Only when these three genes (penP, penI, and PenJ) were simultaneously subcloned in Bacillus subtilis did the plasmid carrier exhibit inducible penicillinase production, as did wild-type B. licheniformis. It was concluded that penJ is involved in the penicillinase induction. The regulation of penP expression by penI and penJ is discussed. 相似文献
3.
5'-Nucleotidase was found in purified rat liver tritosomes. When tritosomes were subfractionated into the membrane and soluble contents fractions, 73% of the total 5'-nucleotidase activity was found in the membrane fraction and 24% in the soluble contents fraction. Immunoblotting using specific polyclonal antibodies against the rat liver plasma membrane 5'-nucleotidase showed that the mobilities on SDS-polyacrylamide gel electrophoresis of both 5'-nucleotidases in the membrane and contents fractions were identical to that of the enzyme in the plasma membranes (Mr = 72,000). 5'-Nucleotidases in the membrane and contents fractions were sensitive to neuraminidase and converted into a form that was 4 kDa smaller after digestion, as observed in the case of plasma membrane enzyme. 5'-Nucleotidases, both from the membrane and contents fractions, were purified using immunoaffinity chromatography, and the isoelectric points, heat stability, and oligomeric structure of the purified enzymes were compared. Isoelectric focusing and the heat stability test indicated the resemblance of the soluble enzyme to the membrane-bound enzyme. However, the membrane-bound enzyme aggregated in the absence of Triton X-100, whereas the soluble enzyme behaved as a dimer. The topography of 5'-nucleotidase in the tritosomal membranes was studied using antibodies against 5'-nucleotidase and neuraminidase treatment. The inhibition of 5'-nucleotidase were not observed in the intact tritosomal fraction until the tritosomes had been disrupted by osmotic shock. These results show that the active sites and the oligosaccharide chains of 5'-nucleotidase are located on the inside surface of the tritosomal membranes. 相似文献
4.
5.
M Kashimura M Okuno S Himeno T Kuroshima H Kawamoto Y Shinomura S Tarui 《Prostaglandins》1988,35(4):583-595
The effect of Prostaglandin D2 (PGD2) on ion transport was investigated in the rat colon in vitro. Ion transport across the intestinal mucosa was estimated by transmucosal potential difference (PD) and short circuit current (Isc) in the Ussing chamber. PGD2 added to the serosal reservoir induced a sustained reduction in PD and Isc at the concentration of higher than 10(-7)M, producing the maximal decrease at 10(-5)M. PGD2 at 10(-5)M completely blocked the increase in PD elicited by prostaglandin E1 (PGE1), theophylline, dibutyryl cAMP or serotonin. Adenylate cyclase activity was determined in the colonic mucosal homogenates after addition of PGD2 and PGE1. Treatment with PGD2 or PGE1 caused a significant increase in the enzyme activity. Combined treatment with both prostaglandins induced no more increase than that elicited by PGE1 alone. These results suggest that PGD2 has an anti-secretory effect on the rat colon and it may regulate the ion transport process through other mechanism than the modification of cyclic AMP concentration in mucosal cells. 相似文献
6.
Purification and characterization of acid phosphatase in rat liver lysosomal contents 总被引:1,自引:0,他引:1
Acid phosphatase in rat liver lysosomal contents, C-APase I, was purified about 5,700-fold over the homogenate with 8.0% recovery, to apparent homogeneity as determined from the pattern on polyacrylamide gel electrophoresis in the presence and in the absence of SDS. The purification procedures included; preparation of crude lysosomal contents, DEAE-Sephacel ion exchange chromatography, hydroxylapatite chromatography, and gel filtration with Sephacryl S-300. The enzyme is composed of three identical subunits with an apparent molecular weight of 48K. The enzyme contains about 11% carbohydrate and the carbohydrate moiety was composed of mannose, fucose, N-acetylglucosamine, and N-acetylgalactosamine in a molar ratio of 20:3:11:1. Sialic acid was not detected in the enzyme. Antisera against the purified C-APase I were raised in goat and the C-APase I was rapidly purified with high yield (10%) by using the specific antibodies coupled to Sepharose 6B. 相似文献
7.
Nucleotide sequence of the penicillinase repressor gene penI of Bacillus licheniformis and regulation of penP and penI by the repressor. 总被引:20,自引:12,他引:8 下载免费PDF全文
Bacillus licheniformis penicillinase genes, penP and penI, are coded on a 4.2-kilobase EcoRI fragment of pTTE21 (T. Imanaka, T. Tanaka, H. Tsunekawa, and S. Aiba, J. Bacteriol. 147:776-186, 1981). The EcoRI fragment was subcloned in a low-copy-number plasmid pTB522 in Bacillus subtilis. B. subtilis carrying the recombinant plasmid pPTB60 (Tcr penP+ penI+) was chemically mutagenized. Of about 150,000 colonies, two penI(Ts) mutant plasmids, pPTB60D13 and pPTB60E24, were screened by the plate assay at 30 and 48 degrees C for penicillinase. By constructing recombinant plasmids between wild-type and mutant plasmids, the mutation points were shown to be located in a 1.7-kilobase EcoRI-PstI fragment. The EcoRI-PstI fragments of the wild-type plasmid and two mutant plasmids were sequenced. A large open reading frame, composed of 384 bases and 128 amino acid residues (molecular weight, 14,983), was found. Since the mutation points were located at different positions in the protein coding region (Ala to Val for pPTB60D13 and Pro to Leu for pPTB60E24), the coding region was concluded to be the penI gene. A Shine-Dalgarno sequence was found 7 bases upstream from the translation start site (ATG). A probable promoter sequence which is very similar to the consensus sequence was also found upstream of the penP promoter, but in the opposite direction. A consensus twofold symmetric sequence (AAAGTATTA CATATGTAAGNTTT) which might have been used as a repressor binding region was found downstream and in the midst of the penP promoter and also downstream of the penI promoter. The regulation of penP and penI by the repressor is discussed. 相似文献
8.
A genomic clone that contains the human gastrin gene was isolated from a human gene library. Restriction endonuclease mapping and DNA sequencing analysis revealed that this gene is about 0.7 kb long, and has an intron. The intron is located at a position that separates the coding region into the peptide region essential for biological activities of gastrin and the non-essential, N-terminal peptide region. 相似文献
9.
H Fujita Y Takata A Kono Y Tanaka T Takahashi M Himeno K Kato 《Biochemical and biophysical research communications》1992,184(2):604-611
A full length cDNA for a human lysosomal membrane sialoglycoprotein (hLGP85) was isolated as a probe of the cDNA of rat LGP85 (rLGP85) from the cDNA library prepared from total mRNA of QGP-1NL cells, a human pancreatic islet tumor cell with a high metastatic activity. The deduced amino acid sequence shows that hLGP85 consists of 478 amino acid residues (MW. 54,289). The protein has 10 putative N-glycosylation sites and 2 hydrophobic regions at the NH2- and near the COOH-termini, respectively. Thus, both domains probably constitute putative transmembrane domains. It exhibits 86% and 79% sequence similarities in amino acids and nucleic acids to rat lysosomal membrane sialoglycoprotein (rLGP85), respectively. The protein contained the short cytoplasmic tail at the COOH-terminus which does not form the glycine-tyrosine sequence (GY motif), the so-called lysosomal targetting signal. 相似文献
10.
Keisuke Tsutsumi Masami Niwa Naoki Kitagawa Sei-ich Yamaga Takeo Anda †Akihiko Himeno ‡Takaya Sato Humayun Khalid Kohtaro Taniyama Shobu Shibata 《Journal of neurochemistry》1994,63(6):2240-2247
Abstract: We identified and characterized 125I-endothelin-1 (125I-ET-1) binding sites in tumor capillaries isolated from human glioblastomas, using the quantitative receptor autoradiographic technique with pellet sections. Quantification was done using the computerized radioluminographic imaging plate system. High-affinity ET receptors were localized in capillaries from glioblastomas and the surrounding brain tissues (KD = 4.7 ± 1.0 × 10?10 and 1.6 ± 0.3 × 10?10M, respectively; Bmax = 161 ± 38 and 140 ± 37 fmol/mg, respectively; mean ± SEM, n = 5). BQ-123, a selective antagonist for the ETA receptor, potently competed for 125I-ET-1 binding to sections of the microvessels with IC50 values of 5.1 ± 0.3 and 5.1 ± 1.5 nM, and 10?6M BQ-123 displaced 84 and 58% of ET binding to capillaries from tumors and brains, respectively. In addition, competition curves obtained in the presence of increasing concentrations of ET-3 showed two components (IC50 = 5.7 ± 2.5 × 10?10 and 1.4 ± 0.2 × 10?6M for tumor microvessels, 1.8 ± 0.6 × 10?10 and 1.1 ± 0.3 × 10?6M for brain microvessels, respectively). Our results indicate that (a) the method we used is simple and highly sensitive for detecting and characterizing various receptors in tumor capillaries, especially in the case of a sparse specimen, and (b) capillaries in glioblastomas express specific high-affinity ET binding sites, candidates for biologically active ET receptors, which predominantly belong to the ETA subtype. 相似文献