全文获取类型
收费全文 | 1722篇 |
免费 | 140篇 |
国内免费 | 1篇 |
出版年
2023年 | 40篇 |
2022年 | 21篇 |
2021年 | 39篇 |
2020年 | 30篇 |
2019年 | 38篇 |
2018年 | 61篇 |
2017年 | 62篇 |
2016年 | 96篇 |
2015年 | 83篇 |
2014年 | 105篇 |
2013年 | 241篇 |
2012年 | 111篇 |
2011年 | 150篇 |
2010年 | 162篇 |
2009年 | 93篇 |
2008年 | 60篇 |
2007年 | 33篇 |
2006年 | 42篇 |
2005年 | 21篇 |
2004年 | 31篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 17篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 23篇 |
1992年 | 20篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 12篇 |
1986年 | 4篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1972年 | 11篇 |
1971年 | 9篇 |
排序方式: 共有1863条查询结果,搜索用时 15 毫秒
61.
Many types of aflatoxin cause problems for both public and animal health. Aflatoxin B1 (AFB1) is the most toxic and commonly encountered fungal toxin that appears in poultry feed and in feeds stored under unsuitable conditions. AFB1 decreases feed quality, egg production and fertility of hatching eggs. Also, AFB1 alters the development of embryos by infecting eggs. We investigated using sequence analysis the changes caused by different concentrations of AFB1 on the promoter sequences of the growth hormone regulated gene-1 (GHRG-1) in chick embryo at 13, 17, 19 and 21 days incubation. DNA isolated from the liver of chick embryos treated with different concentrations of AFB1 was separated using agarose gel electrophoresis to detect apoptosis, and DNA interaction with AFB1 was investigated using plasmids to detect changes in electrophoretic mobility and their effects on DNA. Base changes of the promoter sequences of GHRG-1 in 5 ng/egg, 15 ng/egg and 40 ng/egg doses of AFB1 were increased on day 19 compared to base changes of the same AFB1 doses on day 13. We also found that AFB at different concentrations changed the mobility of DNA by binding to it, and that high doses of AFB1 destroyed DNA. The DNA interaction study using plasmid demonstrated that AFB1 at high doses was bound to plasmid DNA, slowed its mobility and inhibited restriction cuts. 相似文献
62.
Ayşe Eken Onur Erdem Zorica Arsova‐Sarafinovska Cemal Akay Ahmet Sayal Nadica Matevska Ljubica Suturkova Koray Erten Yaşar Özgök Aleksandar Dimovski Ahmet Aydin 《Journal of biochemical and molecular toxicology》2013,27(3):213-218
Manganese superoxide dismutase (MnSOD) is the most effective antioxidant enzyme in mitochondria and protects cells from reactive oxygen species‐induced oxidative damage. The aim of this study was to investigate the association between MnSOD Ala‐9Val gene polymorphism and prostate cancer (PCa) risk in Turkish men with prostate cancer. 33 patients with PCa and 81 control individuals were included in the study. We observed an association between MnSOD Ala/Ala frequency and a higher PCa risk. In addition, we found that the increased risk of early‐onset PCa (under age of 65) in the men homozygous for Ala allele was higher than the men homozygous for Val allele. However, we determined that MnSOD Ala‐9Val genotype was not associated with the aggressiveness of the disease. The results of our study suggest that MnSOD Ala/Ala genotype may influence on early‐onset of PCa patients, but no effect on subsequent development of the disease in Turkish men. However, our study has a limitation that is small numbers of individuals for cases and controls. Therefore, the presented study limited our statistical power to fully investigate the gene polymorphism on cancer risk. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:213‐218, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21472 相似文献
63.
Sevgi Yardim-Akaydin Aylin Sepici Yeşim Özkan Meral Torun Bolkan Şimşek Vesile Sepici 《Free radical research》2013,47(6):623-628
Free radicals are implicated in many diseases including atherosclerosis, cancer and also in rheumatoid arthritis. Reaction of uric acid with free radicals, such as hydroxyl radical and hypochlorous acid (HOCl) results in allantoin production. In this study, we measured the serum allantoin levels, oxidation products of uric acid, as a marker of free radical generation in rheumatoid arthritis. Fasting blood samples were obtained from 21 rheumatoid patients and 15 healthy controls. In this study, the serum allantoin and uric acid levels were measured by a gas chromatography–mass spectrometry method and the ratios were calculated. The mean allantoin and uric acid levels and ratios in the patient group were 22.1±11.3, 280.5±65.0 and 8.0±3.7?μM, while in the control group they were 13.6±6.3, 278.3±53.6 and 4.9±2.1?μM, respectively. The effects of gender, age, menopausal status, duration of disease and medications on serum allantoin and uric acid levels of the patient and control groups were studied. Our results suggest that uric acid acts as a free radical scavenger and thus is converted to allantoin. Increased allantoin levels suggest the possible involvement of free radicals in rheumatoid arthritis. 相似文献
64.
Süreyya Ölgen PInar Varol Tülay Çoban Doğu Nebioğlu 《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):334-340
The in vitro antioxidant effects of novel N-substituted indole-3-carboxamides (I3CDs) 1-10 on rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels and their free radicals scavenging properties were determined by the inhibition of superoxide anion formation (SOD). Among the synthesized compounds, 4, 5, 8 and 9 significantly inhibited SOD with an inhibition range at 84–100% at 10? 3 M concentration. The presence of halo substituents both ortho- and para- positions of these compounds resulted 100% inhibition of SOD. Comparison the activity results of halogenated and non-halogenated derivatives suggested that the halogenated compounds are more active than the non-halogenated compounds. On the other hand, the introduction of a para fluoro benzyl in the 1-position of indole (compounds 7, 8) has more impact on the SOD inhibition when the benzamide ring was mono halogenated. However, none of other compounds had a significant inhibitory effects on the level of lipid peroxidation. 相似文献
65.
Pinar Bozkaya Sureyya Ölgen Tulay Çoban Dogu NebIoglu 《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):319-325
The antioxidant role of novel N-substituted indole-2-carboxamides (I2CDs) was investigated for their inhibitory effects on superoxide anion (O2? ) and lipid peroxidation (LP). Among the synthesized I2CDs, 3, 4, 6, 8 and 9 significantly inhibited O2· ? with an inhibition range at 70–98%. Examination of substituent effects on activity showed that both the ortho- and para-positions of the benzamide residue needs to be dichlorinated in order to get a maximum inhibitory effect on superoxide anion. In general, halogenated derivatives were found more active then the non-halogenated ones. However, none of the I2CDs had a significant inhibitory effects on the level of lipid peroxidation; only compounds 7 and 10 moderately decreased LP levels by over 50% at 10? 3 M concentrations. 相似文献
66.
Ahmet Özdemir Gulhan Turan-Zitouni Zafer Asim Kaplancikli Pierre Chevallet 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):511-516
The increasing clinical importance of drug-resistant mycobacterial pathogens has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new triazoles were synthesized and evaluated for antituberculosis activity. A series of 4-arylidenamino-4H-1,2,4-triazole-3-thiol derivatives (2a–n) were synthesized from the treatment of 4-amino-4H-1,2,4-triazoles-3-thiol (1) with the respective aldehydes and were evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv (ATCC 27294), using the BACTEC 460 radiometric system and BACTEC 12B medium. Compound 2k showed an intereting activity at 6.25 μg/mL with a 87 percentage inhibition. 相似文献
67.
The antioxidant activity of some amido-carbonyl oximes containing a C=O and –NH–R adjacent to the oxime group, [Phenyl-C(=O)-C(=N-OH)-N(-H)-Phenyl(-R)] where R= H, 4-chloro, 4-methyl, 4-methoxy, 3,4-dichloro, 3,4-dimethyl, 3-chloro-4-dimethyl, 3-chloro-4-methoxy, naphthyl and an amido-carbonyl dioxime were investigated in vitro by ferric thiocyanate, total reducing power by potassium ferricyanide reduction, 1,1-diphenyl-2- picryl-hydrazyl (DPPH·) free radical scavenging, ferrous ions chelating, superoxide anion radical scavenging and hydrogen peroxide scavenging activity assays. The results indicated that the amido-carbonyl oximes have powerful antioxidant capacity. 相似文献
68.
MEHMET ÇI˙FTÇI˙ YAVUZ DEMI˙R I˙SMAIL ÖZMEN ÖKKEŞ ATICI 《Journal of enzyme inhibition and medicinal chemistry》2013,28(1):71-76
The present study was undertaken to determine in vivo and in vitro effects of some plant growth regulators on rat erythrocyte carbonic anhydrase (CA) and glucose-6-phosphate dehydrogenase (G6PD) activities. Both in vivo and in vitro, spermidine and kinetin did not affect enzymatic activities of CA and G6PD, whereas putrescine decreased these activities, and abscisic acid increased them. Since plants use such growth regulators, their effects should be considered on mammals consuming them since they may possess important biological effects. 相似文献
69.
Yildiz Öner-İyidoğan Hikmet Koçak Muhammed Seyidhanoğlu Figen Gürdöl Ahmet Gülçubuk Funda Yildirim Aydin Çevik Müjdat Uysal 《Journal of physiology and biochemistry》2013,69(4):677-686
Fetuin-A is synthesized in the liver and is secreted into the bloodstream. Clinical studies suggest involvement of fetuin-A in metabolic disorders such as visceral obesity, insulin resistance, diabetes, and fatty liver. Curcumin is extracted from the rhizome Curcuma longa and has been shown to possess potent antioxidant, anticarcinogenic, anti-inflammatory, and hypoglycemic properties. In this study, we investigated the effect of curcumin treatment on serum fetuin-A levels as well as hepatic lipids and prooxidant–antioxidant status in rats fed a high-fat diet (HFD). Male Sprague–Dawley rats were divided into six groups. Group 1 was fed control diet (10 % of total calories from fat). Groups 2 and 3 were given curcumin (100 and 400 mg/kg bw/day, respectively ) by gavage for 8 weeks and were fed control diet. Group 4 was fed with HFD (60 % of total calories from fat). Groups 5 and 6 received HFD together with the two doses of curcumin, respectively. Curcumin treatment appeared to be effective in reducing liver triglycerides and serum fetuin-A levels. These findings suggest that the reduction of fetuin-A may contribute to the beneficial effects of curcumin in the pathogenesis of obesity. 相似文献
70.