全文获取类型
收费全文 | 8461篇 |
免费 | 85篇 |
国内免费 | 158篇 |
出版年
2024年 | 6篇 |
2023年 | 143篇 |
2022年 | 132篇 |
2021年 | 217篇 |
2020年 | 280篇 |
2019年 | 408篇 |
2018年 | 338篇 |
2017年 | 176篇 |
2016年 | 185篇 |
2015年 | 100篇 |
2014年 | 571篇 |
2013年 | 1037篇 |
2012年 | 322篇 |
2011年 | 536篇 |
2010年 | 403篇 |
2009年 | 401篇 |
2008年 | 368篇 |
2007年 | 416篇 |
2006年 | 345篇 |
2005年 | 309篇 |
2004年 | 225篇 |
2003年 | 164篇 |
2002年 | 141篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 10篇 |
1998年 | 17篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1994年 | 13篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1987年 | 7篇 |
1985年 | 103篇 |
1984年 | 172篇 |
1983年 | 126篇 |
1982年 | 129篇 |
1981年 | 114篇 |
1980年 | 114篇 |
1979年 | 90篇 |
1978年 | 75篇 |
1977年 | 85篇 |
1976年 | 85篇 |
1975年 | 77篇 |
1974年 | 55篇 |
1973年 | 69篇 |
1972年 | 19篇 |
排序方式: 共有8704条查询结果,搜索用时 31 毫秒
61.
62.
63.
《Bioscience, biotechnology, and biochemistry》2013,77(7):1596-1600
Saccharomyces cerevisiae is the main microorganism used in wine brewing, because this microbe has potent ability to produce alcohol dehydrogenase. We have recently discovered that some genera of mushroom produced alcohol dehydrogenase, and made wine by using a mushroom in place of S. cerevisiae. The highest alcohol concentration in this wine was achieved with Pleurotus ostreatus (2.6 M, 12.2%). In the case of Agaricus blazei, the same alcohol concentration (1.7 M, 8%) was produced under both aerobic and anaerobic conditions. This wine produced by A. blazei contained about 0.68% β-D-glucan, which is known to have a preventive effects against cancer. The wine made by using Flammulina velutipes showed thrombosis-preventing activity, giving a prolonged thrombin clotting time 2.2-fold that of the control. Thus, the wine made by using mushroom seems to be a functional food which can be expected to have preventive effects against cancer and thrombosis 相似文献
64.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2456-2464
We have established a unique enzymatic approach for obtaining sulfated disaccharides using Bacillus circulans β-D-galactosidase-catalyzed 6-sulfo galactosylation. When 4-methyl umbelliferyl 6-sulfo β-D-galactopyranoside (S6Galβ-4MU) was used as a donor, the enzyme induced transfer of 6-sulfo galactosyl residue to GlcNAc acceptor. As a result, the desired compound 6'-sulfo N-acetyllactosamine (S6Galβ1-4GlcNAc) and its positional isomer 6'-sulfo N-acetylisolactosamine (S6Gal β1-6GlcNAc) were observed by HPAEC-PAD, in 49% total yield based on the donor added, and in a molar ratio of 1:3.5. With a glucose acceptor, the regioselectivity was substantially changed and S6Galβ1-2Glc was mainly produced along with β-(1-1)α,β-(1-3),β-(1-6) isomers in 74% total yield. When methyl α-D-glucopyranoside (Glcα-OMe) was an acceptor, the enzyme also formed mainly S6Galβ1-2Glcα-OMe with its β-(1-6)-linked isomer in 41% total yield based on the donor added. In both cases, it led to the predominant formation of β-(1-2)-linked disaccharides. In contrast, with the corresponding methyl β-D-glucopyranoside (Glcβ-OMe) acceptor, S6Galβ1-3Glcβ-OMe and S6Galβ1-6Glcβ-OMe were formed in a low total yield of 12%. These results indicate that the regioselectivity and efficiency on the β-D-galactosidase-mediated transfer reaction significantly depend on the anomeric configuration in the glucosyl acceptors. 相似文献
65.
《Bioscience, biotechnology, and biochemistry》2013,77(12):2470-2474
β2 integrins (CD11s/CD18) promote the attachment of leukocytes to vascular endothelial cells. We performed in this study sucrose loading to rats with moderate postprandial hyperglycemia with/without once-daily dosing of the α-glucosidase inhibitor, miglitol, for 4 days under 4-h fasting conditions. The streptozotocin (STZ)-treated rats showed moderate postprandial hyperglycemia on days 1 and 4. The gene expression was higher for CD11a with fasting and 3-h postprandial on day 1, and with fasting on day 4, for CD11b with fasting on day 1 and 3-h postprandial on day 4, and for CD18 with fasting on days 1 and 4 in peripheral leukocytes from the STZ-treated rats than in peripheral leukocytes from the saline-treated rats. Miglitol reduced postprandial hyperglycemia and the gene expression of CD11a with fasting and of CD11b 3-h postprandial on day 4. These results indicate that inhibiting postprandial hyperglycemia reduced the mRNA expression of β2 integrins in peripheral leukocytes of moderately postprandial hyperglycemic rats. 相似文献
66.
《Saudi Journal of Biological Sciences》2021,28(11):6289-6296
According Global Cancer Statistics 2020 GLOBOCAN estimates female breast cancer was found as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), and the fourth leading cause (6.9%) of cancer death among women worldwide. Identification of new diagnostic marker sharply characterize the tumor feature is intensive need. The present work was performed to investigate the involvement of the INF-γ + 874 T/A gene polymorphism in different breast cancer prognostic factors. Polymorphism detection analysis was performed on 163 subjects from breast cancer patients, 79 with inflamed cells of breast patients and 144 controls. The gene polymorphism was detected using the amplification refractory mutation system- polymerase chain reaction method (ARMS-PCR). The distribution of INF-γ T + 874A gene polymorphism shows strong significant association between INF-γ + 874 T/A genotypes TT in BC patients (ORTT: 6.41 [95% CI = 2.72–15.1] P < 0.0001) as well as strong significant association regarding T allele (ORT: 1.99 [95% CI = 1.43–2.76] P < 0.0001) when compared to the healthy control. In ICB group the strong association was noted with INF-γ + 874 T/A genotypes AT genotype (ORAT: 2.28 [95% CI = 1.22–4.29] P = 0.007). From the different histological BC hormonal markers the human epidermal growth factor receptor 2 (HER2) was showing significant association in INF-γ + 874 T/A genotypes TT (P = 0.03) and recessive model (TT versus AA + AT P = 0.03). Concerning different BC prognostic models, the poor prognostic one of luminal B, (ER+ve PR+ve Her2+ve) show significant association in the host INF-γ + 874 T/A genotype (TT, P = 0.03) and recessive model (TT versus AA + AT P = 0.02) when compared to the good prognostic hormonal status luminal A model, (ER+ve PR+ve Her2-ve). It seems that this is the first study that interested in correlate the INF-γ + 874 T/A gene polymorphisms in Egyptian BC patients. T allele, TT genotype and recessive model of the INF-γ + 874 T/A gene variants were documented as risk factors for BC pathogenesis. It may be used as practical biomarker to guide the BC carcinogenesis and risk process. 相似文献
67.
《Free radical research》2013,47(4):235-241
Intramolecular electron transfer in hen egg-white lysozyme between tryptophan and tyrosine units was investigated by means of pulse radiolysis in the temperature range 288–333 K. An Arrhenius plot for the kinetics of this process shows a sharp break at ~303 K (30°C) compatible with the trend noted earlier (cf P. Jolles, et al. BBA. 491. 354. (1977)) on the Arrhenius plot for kinetics of bacterial substrate digestion by lysozyme. The departure from linearity of the Arrhenius plot for intramolecular electron transfer is interpreted in terms of local intralobe fluctuations of the native structure of lysozyme. It is suggested that such an approach can be useful for probing predenaturational changes in proteins. 相似文献
68.
Satoru Masuda Shigefumi Kuwahara Toshio Suguro Kenji Mori 《Bioscience, biotechnology, and biochemistry》2013,77(11):2515-2520
The (S)-enantiomer of the sex pheromone of the yellow scale (Aonidiella citrina), (S,E)-6-isopropyl-3,9-dimethyl-5,8-decadienyl acetate, was stereoselectively synthesized from (R)-(+)-citronellic acid. 相似文献
69.
Akira Hirota Akinori Suzuki Hiroshi Suzuki Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(3):643-647
Three metabolites designated Cyl–1, –2 and –3 were isolated as plant growth regulators from culture filtrate of Cylindrocladium scoparium Morgan, a phytopathogenic fungus. Cy1–2 was obtained as pure crystals, and it revealed marked inhibitory activity on the root growth of lettuce seedlings. Cyl–1 showed inhibition on the same organ, while Cyl–3 showed promotion. 相似文献
70.
Noriharu Umetsu Jun Kaji Keiko Aoyama Kinjiro Tamari 《Bioscience, biotechnology, and biochemistry》2013,77(10):1867-1874
The occurence of tenuazonic acid (T.A.), which had been isolated from the culture broth of blast fungus, in blast-diseased rice plants was surveyed to ascertain whether or not this substance is one of the vivotoxins. T.A. was detected in four of six samples of blast-diseased rice plants, two of which had relatively high T.A. contents; 379 and 91 mg per kg of the samples (dry weight).Besides T.A., coumarin, o-coumaric acid and piricularin were also isolated from blast-diseased rice plants. The molecular formula of the last substance, which was tentatively presented in a previous paper, was corrected to C18H30N2O5 from the results of high resolution mass spectrometry. 相似文献