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21.
22.
Regulation of angiotensin converting enzyme activity in cultured human vascular endothelial cells 总被引:1,自引:0,他引:1
N Iwai M Matsunaga T Kita M Tei C Kawai 《Biochemical and biophysical research communications》1987,149(3):1179-1185
Angiotensin converting enzyme (ACE) of vascular endothelial cells is suggested to control vascular wall tonus through the conversion of angiotensin I (AI) to angiotensin II (AII) and the degradation of bradykinin. To obtain more insight into the pathophysiological significance of ACE of vascular endothelial cells, we studied the regulation of ACE produced by cultured human umbilical vein endothelial cells (EC). Phorbol 12-myristate 13-acetate (PMA) increased the cellular and medium ACE activity, accompanied by a marked morphological change in EC. N'-O'-dibutylyladenosine 3';5'-cyclic monophosphate (db-cAMP) increased only the cellular ACE activity and not the medium ACE activity. The effect of isoproterenol with 0.1mM theophylline mimicked that of db-cAMP. These findings suggest that PMA and cAMP-related agents participate in the control of vascular wall tonus through the positive regulation of ACE produced by vascular endothelial cells. 相似文献
23.
Jong Wan Park Ho Sub Jung Hea Yeon Lee Tomoji Kawai 《Biotechnology and Bioprocess Engineering》2005,10(6):505-509
For the purpose of developing a direct label-free electrochemical detection system, we have systematically investigated the
electrochemical signatures of each step in the preparation procedure, from a bare gold electrode to the hybridization of label-free
complementary DNA, for the streptavidin-modified electrode. For the purpose of this investigation, we obtained the following
pertinent data; cyclic voltammogram measurements, electrochemical impedance spectra and square wave voltammogram measurements,
in Fe(CN)6
3−/Fe(CN)6
4− solution (which was utilized as the electron transfer redox mediator). The oligonucleotide molecules on the streptavidin-modified
electrodes exhibited intrinsic redox activity in the ferrocyanide-mediated electrochemical measurements. Furthermore, the
investigation of electrochemical electron transfer, according to the sequence of oligonucleotide molecules, was also undertaken.
This work demonstrates that direct label-free oligonucleotide electrical recognition, based on biofunctional streptavidin-modified
gold electrodes, could lead to the development of a new biosensor protocol for the expansion of rapid, cost-effective detection
systems. 相似文献
24.
25.
Haruo Seto Noboru Ōtake Hiroyuki Kawai Si-Qi Luo Fu-Gang Qian Sheng-Li Pan 《Bioscience, biotechnology, and biochemistry》2013,77(6):1607-1611
Sixteen triterpenoid glycosides, named S13 to S25, S37, S38 and S40, were isolated from the root of Bupleurum polyclonum Y. Li et S. L. Pan, and their structures were determined from NMR spectral analyses. Among them, S24, S37 and S38 were found to be new substances, their structures being established as 30-β-d-glucopyranosyl 30-hydroxysaikosaponin-b2, 2″-O-acetylsaikosaponin-b2 and 3″-O>-acetylsaikosaponin-b2, respectively. 相似文献
26.
Fusako Kawai Kensei Maezato Hideaki Yamada Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(9):1675-1679
The formation of D-pantothenic acid-α-glucoside (PaA-α-G) was found from D-pantothenic acid (PaA) and maltose in incubation mixtures of microorganisms, especially Saccharomyces yeasts and Sporobolomyces coralliformis IFO 1032. The reaction conditions were investigated for formation of PaA-α-G by resting cells of Spor. coralliformis. The formation of the compound increased with PaA concentration (3~20 mg/ml). The yield was maximum at 5~10 mg/ml of PaA. Cetyl trimethyl ammonium bromide (0.1 %) promoted the formation of PaA-α-G. Sucrose was the optimal α-glucosyl donor. When 30 mg/ml of sucrose was fed to the reaction mixture (initial sucrose, 100 mg/ml; and PaA, 10 mg/ml) at 12-hr intervals, 5.74 mg/ml (3.30 mg/ml as PaA) of PaA-α-G was formed in 48-hr incubation at 28°C with shaking. PaA-α-G was also formed by yeast α-glucosidase, mold maltase and the cell-free extract of Spor. coralliformis. The compound showed approximately 9~10% and 0.1~0.3% (molar ratio) of activity of PaA for Saccharomyces carlsbergensis ATCC 9080 and Lactobacillus plantarum ATCC 8014, respectively. The compound had the same microbiological activity as authentic 4′-O-(α-D-glucopyranosyl)-D-pantothenic acid. 相似文献
27.
l-Glutamic acid was formed from d-, l-, and dl-PCA with cell-free extract of Pseudomonas alcaligenes ATCC-12815 grown in the medium containing dl-PCA as a sole source of carbon and nitrogen. The enzyme(s) involved in this conversion reaction was distributed in the soluble fraction within the cell and in 0.5 saturated fraction at the fractionation procedure with the saturation of ammonium sulfate. Optimum pH of this enzyme(s) lied at pH 8.5 and optimum temperature was 30°C. Cu (5 × 10?3 m) inhibited the reaction considerably while Ca or Fe accelerated it. PALP (1×10?3 m) also gave an enhanced activity to some extent. The enzyme preparation converted dextro-rotatory enan-thiomorph of PCA to its laevo-rotatory one which in turn was not converted to the opposite rotation direction by this enzyme. Furthermore, the preparation did not, if any, show d-glutamic acid racemase activity. Isotopic experiments with using dl-PCA-1-14C revealed that l-glutamic acid-1-14C was formed by the cleavage of –CO–NH– bond of pyrrolidone ring of PCA. It was concluded that dl-PCA when assimilated by the present bacterium is at first transformed to l-PCA by the optically isomerizing enzyme and subsequently is cleaved to l-glutamic acid probably by the PCA hydrolysing enzyme. 相似文献
28.
Yoshio Kawai Teruyuki Fujita Shozo Koga 《Bioscience, biotechnology, and biochemistry》2013,77(8):1799-1802
Ribosomal particles of E. coli were examined by using a heat leakage scanning calorimeter. Remarkable changes were observed in thermograms of 70S ribosomes and their subunits when the Mg2+ concentration was raised from 1 mm to 10 mm. It was suggested that ribosomal subunits exist in more than one conformation, and changes in their conformation might be the primary cause of the association-dissociation process of ribosomes. Comparisons of thermograms of RNase- and chymotrypsin-treated, as well as non-treated SOS and 30S subunits suggest that conformational changes in each subunit may be ascribed to changes in rRNA. 相似文献
29.
Toshiyuki Yamaguchi Romanus Edy Prabowo Yuu Ohshiro Takaki Shimono Diana Jones Hiroshi Kawai 《Biofouling》2013,29(4):325-333
The Titan Acorn barnacle, Megabalanus coccopoma, a native of the tropical eastern Pacific, has become established in the western Atlantic (Brazil and the northern Gulf of Mexico to the Carolinas), northwestern Europe and the western Indian Ocean (Mauritius), and therefore its dispersal capabilities are well known. This study reports its introduction to Japan and confirms its occurrence in Australia. In an attempt to determine the source of this introduction, phylogeographic techniques, involving cytochrome c oxidase I sequences of various widely separate populations of M. rosa and M. volcano, were utilized. No significant genetic differentiation or haplotype patterns between widely separated populations of each of the three species were found. Lack of such differentiation indicates recent geographical isolation and thus negates a null hypothesis predicting that the occurrence of one of more of these species in Australia was natural. 相似文献
30.
Hiroyasu Kawai Kenji Yamamoto Akira Kimura Tatsurokuro Tochikura 《Bioscience, biotechnology, and biochemistry》2013,77(7):1741-1743
An E. coli strain, SH209, harboring pLC9–12 exhibited 5- to 6-fold higher γ-glutamyltranspeptidase activity than the wild-type strain, at each growth temperature tested. Maximum activity was observed at 20 ~ 25°C, as was observed with the wild type. A homogeneous enzyme preparation was obtained from the periplasmic fraction of the strain by a simple three-step method. The conditions for γ-glutamyl-DOPA synthesis from l-glutamine and l-DOPA were investigated using the enzyme preparation. Under the best conditions, the maximal yield of 79%, equivalent to 158 mm (51.5 g/l) of γ-glutamyl-DOPA as to both substrates, was obtained. γ-Glutamyl-DOPA was isolated from the reaction mixture and identified using an amino acid analyzer after hydrolysis with HCl or γ-glutamyltranspeptidase. 相似文献