全文获取类型
收费全文 | 1612篇 |
免费 | 76篇 |
出版年
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 27篇 |
2017年 | 25篇 |
2016年 | 37篇 |
2015年 | 67篇 |
2014年 | 56篇 |
2013年 | 126篇 |
2012年 | 110篇 |
2011年 | 99篇 |
2010年 | 73篇 |
2009年 | 66篇 |
2008年 | 108篇 |
2007年 | 117篇 |
2006年 | 91篇 |
2005年 | 96篇 |
2004年 | 108篇 |
2003年 | 83篇 |
2002年 | 78篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 25篇 |
1998年 | 17篇 |
1997年 | 10篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 14篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有1688条查询结果,搜索用时 312 毫秒
41.
Akihiko Kojima Satoshi Takita Tatsunobu Sumiya Koji Ochiai Kazuhiko Iwase Tetsuya Kishi Akira Ohinata Yuichi Yageta Tokutaro Yasue Yasushi Kohno 《Bioorganic & medicinal chemistry letters》2013,23(19):5311-5316
We previously identified KCA-1490 [(?)-6-(7-methoxy-2-trifluoromethyl-pyrazolo[1,5-a]pyridin-4-yl)-5-methyl-4,5-dihydro-3-(2H)-pyridazinone], a dual PDE3/4 inhibitor. In the present study, we found highly potent selective PDE4 inhibitors derived from the structure of KCA-1490. Among them, N-(3,5-dichloropyridin-4-yl)-7-methoxy-2-(trifluoromethyl)pyrazolo[1,5-a]pyridine-4-carboxamide (2a) had good anti-inflammatory effects in an animal model. 相似文献
42.
Hideo Ochiai Hiroshi Eguchi Shunsuke Noguchi Yutaro Hayashi Hideaki Nishino Masaru Kawamura Chau H. Wu 《Journal of molecular recognition : JMR》2013,26(1):32-37
Glutathione S‐transferase (GST) was found to complex with the Na+,K+‐ATPase as shown by binding assay using quartz crystal microbalance. The complexation was obstructed by the addition of antiserum to the α‐subunit of the Na+,K+‐ATPase, suggesting the specificity of complexation between GST and the Na+,K+‐ATPase. Co‐immunoprecipitation experiments, using the anti‐α‐subunit antiserum to precipitate the GST‐Na+,K+‐ATPase complex and then using antibodies specific to an isoform of GST to identify the co‐precipitated proteins, revealed that GSTπ was complexed with the Na+,K+‐ATPase. GST stimulated the Na+,K+‐ATPase activity up to 1.4‐fold. The level of stimulation exhibited a saturable dose–response relationship with the amount of GST added, although the level of stimulation varied depending on the content of GSTπ in the lots of GST received from supplier. The stimulation was also obtained when recombinant GSTπ was used, confirming the results. When GST was treated with reduced glutathione, GST activity was greatly stimulated, whereas the level of stimulation of the Na+,K+‐ATPase activity was similar to that when untreated GST was added. When GST was treated with H2O2, GST activity was greatly diminished while the stimulation of the Na+,K+‐ATPase activity was preserved. The results suggest that GSTπ complexes with the Na+,K+‐ATPase and stimulates the latter independent of its GST activity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
43.
The trypsin inhibitors in buckwheat seeds were isolated by affinity chromatography on trypsin-Sepharose 4B, and the components were fractionated by chromatography on DEAE-Sepharose CL-6B. The major components, inhibitors I, II and III, were found to be homogeneous proteins with molecular weight of about 8,000. Trypsin inhibitory activity was more pronounced than the chymotrypsin inhibitory activity in all the inhibitor preparation obtained. The three major inhibitors had similar amino acid compositions and had no detectable amounts of tryptophan and carbohydrate. A high level of acidic and basic amino acid residues and a low level of methionine, tyrosine and phenylalanine residues characterized the inhibitors. Although the inhibitors I and II were particularly thermostable, inhibitor III, the most abundant component, was shown to be relatively heat-labile. 相似文献
44.
A strongly acidic amino acid—N-carboxymethyl-L-serine—, not previously known in nature, has been isolated from asparagus (Asparagus officinalis) shoots. Some unique properties of this amino acid, such as a much bigger mobility to anode on high voltage paper electrophoresis (pH 3.6) than aspartic acid and characteristic changes of NMR spectra in aqueous solution with various pD, were discussed in relation to its structure. 相似文献
45.
Kohei Oda Takanori Nakazima Takao Terashita Ken-ichiro Suzuki Sawao Murao 《Bioscience, biotechnology, and biochemistry》2013,77(11):3073-3080
A S-PI(Pepstatin Ac)-insensitive carboxyl proteinase was found in culture filtrate of a Xanthomonas sp. bacterium. The carboxyl proteinase was highly purified and about 100 mg of the enzyme was obtained from 601 of culture filtrate, with a recovery of 25%. The optimum condition for the action of the purified enzyme toward casein was approx. pH 2.7 and its activity was not inhibited by any of such carboxyl proteinase inhibitors as Pepstatin, S-PI, and DAN but EPNP inhibited it. Such behavior of the enzyme against inhibitors resembles that of Pseudomonas sp. carboxyl proteinase, the first found from a bacterium. Some differences were observed, however, in their properties such as optimum pH, isoelectric point, and amino acid composition. 相似文献
46.
Kazutami Imai Tsuyoshi Sugio Takanori Tsuchida Tatsuo Tano 《Bioscience, biotechnology, and biochemistry》2013,77(7):1349-1354
Effect of heavy metal ions on the growth and the iron-oxidizing activity of Thiobacillus ferrooxidans were investigated.Cupric, zinc, cadmium, and chromium ions had no effect on the growth and the iron-oxidizing activity of cell suspensions or cell-free extracts of the bacterium in high concentrations (10?3~10?2M). Lead ion delayed the start of the growth slightly in 10?3 M, but it did not inhibit the iron-oxidizing activity of the cells in the concentration. Tin and molybdenum oxide ions inhibited both of them in the concentration above 10?3 M.Mercuric mercurous, and silver ions had the most harmful effect. In the concentration of 10?3 .M, each of the cations inhibited almost completely both the growth and the iron-oxidizing activity of the cells.In the experiments with cell-free extracts it was observed that the activity of cytochrome oxidase (cytochrome a597) operating in the iron-oxidizing system of the bacterium was specifically inhibited with mercuric ion in the concentration above 5 × 10?4 M. 相似文献
47.
Takanori Kasai Katsuhisa Furukawa Sadao Sakamura 《Bioscience, biotechnology, and biochemistry》2013,77(12):2489-2490
The antibacterial effects of salivary nitrate/nitrite on the growth of three Desulfovibrio species were examined. The bacteria did not grow on plates with ≥0.2 mM nitrate or ≥1.0 mM nitrite. They were also incubated in filter-sterilized saliva. D. desulfuricans was reduced on the order of >102 compared with the control solution (phosphate-buffered saline) in nine out of the 10 participants. 相似文献
48.
A methanol-utilizing phototrophic bacterium, strain M402, was isolated from surface water of an acidic hot spring. The isolated strain was identified as Rhodopseudomonas acidophila from its morphological and physiological characters. Profiles of the utilization of non-aromatic compounds as carbon sources by this strain were in good agreement with those of some strains of R. acidophila reported by Pfennig [J. Bacteriol., 99, 597 (1969)]. However, strain M402 was found to be capable of utilizing vanillic acid, vanillin, vanillyl alcohol, ferulic acid, veratric acid, syringic acid, syringal-dehyde and benzyl alcohol as carbon sources under anaerobic-light conditions. Although Pfennig did not refer to these abilities of his strains, these notable characters of strain M402 seem to be additional new characters of R. acidophila. 相似文献
49.
Takanori Kasai Minoru Sano Sadao Sakamura 《Bioscience, biotechnology, and biochemistry》2013,77(12):2449-2453
l-Ng-Methylarginine, l-Ng,Ng-dimethylarginine and ethanolamine were isolated from basic amino acids fraction of broad bean (Vicia faba L.) seed. The presence of Ng,N′g-dimethylarginine was also suggested. 相似文献
50.
Kohei Oda Takanori Imanishi Yoshito Yamane Yoshie Ueno Yoshiharu Mori 《Bioscience, biotechnology, and biochemistry》2013,77(5):882-890
Addition of γ-aminobutyric acid (GABA) and angiotensin converting enzyme (ACE)-inhibitory peptides to the pickles was studied in order to develop a new type of pickles that reduce blood pressure. Based on the outcome of these studies, a new type of fermentation bed composed of rice bran and white miso has been successfully developed. The advantage of such pickles is that they not only contain both GABA and ACE-inhibitory peptides, but also that their taste and flavor are excellent, with colors close to the original ones. The new type of pickles could temporarily reduce blood pressure in two types of rats, spontaneously hypertensive rats and NaCl-sensitive model rats. Thus, the newly developed pickles appear to be beneficial for pickle business. 相似文献