全文获取类型
收费全文 | 2311篇 |
免费 | 193篇 |
国内免费 | 1篇 |
专业分类
2505篇 |
出版年
2023年 | 10篇 |
2022年 | 30篇 |
2021年 | 33篇 |
2020年 | 19篇 |
2019年 | 29篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 53篇 |
2015年 | 125篇 |
2014年 | 150篇 |
2013年 | 175篇 |
2012年 | 191篇 |
2011年 | 189篇 |
2010年 | 109篇 |
2009年 | 108篇 |
2008年 | 127篇 |
2007年 | 118篇 |
2006年 | 109篇 |
2005年 | 106篇 |
2004年 | 99篇 |
2003年 | 71篇 |
2002年 | 70篇 |
2001年 | 67篇 |
2000年 | 56篇 |
1999年 | 46篇 |
1998年 | 31篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 7篇 |
1992年 | 26篇 |
1991年 | 40篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1971年 | 4篇 |
1969年 | 5篇 |
排序方式: 共有2505条查询结果,搜索用时 15 毫秒
31.
32.
33.
Kun-Shan Cheng Yan-Chiou Liao Mu-Yuan Chen Tang-Ching Kuan Yi-Han Hong Li Ko Wen-Yeh Hsieh Chien-Liang Wu Ming-Ren Chen Chih-Sheng Lin 《International journal of biological sciences》2013,9(6):557-563
Ventricular septal defect (VSD) is the most common form of congenital heart diseases. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases involved in causal cardiac tissue remodeling. We studied the changes of circulating MMP-2 and MMP-9 activities in the patients with VSD severity and closure. There were 96 children with perimembranous VSD enrolled in this study. We assigned the patients into three groups according to the ratio of VSD diameter/diameter of aortic root (Ao). They were classified as below: Trivial (VSD/Ao ratio ≤ 0.2), Small (0.2 < VSD/Ao ≤ 0.3) and Median (0.3 < VSD/Ao) group. Plasma MMP-2 and MMP-9 activities were assayed by gelatin zymography.There was a significant higher MMP-2 activity in the VSD (Trivial, Small and Median) groups compared with that in Control group. The plasma MMP-9 activity showed a similar trend as the findings in MMP-2 activity. After one year follow-up, a significant difference in the MMP-9 activity was found between VSD spontaneous closure and non-closure groups. In conclusion, a positive trend between the severity of VSD and activities of MMP-2 and MMP-9 was found. Our data imply that MMP-2 and MMP-9 activities may play a role in the pathogenesis of VSD. 相似文献
34.
35.
Huai-Ren Chang Jen-Che Hsieh Bang-Gee Hsu Ling-Yi Wang Michael Yu-Chih Chen Ji-Hung Wang 《PloS one》2013,8(11)
Background
Metabolic syndrome has been shown to be associated with lower levels of plasma N-terminal pro-B-type natriuretic peptide (Nt-proBNP) in the general population. We sought to elucidate the relationship between Nt-proBNP and components of metabolic syndrome in patients with congestive heart failure (CHF).Methods
Fasting blood samples were obtained from 93 patients in our institution. Plasma levels of Nt-proBNP and other biochemical data were measured. The New York Heart Association (NYHA) classification system (I-IV) was used to define the functional capacity of CHF. Metabolic syndrome and its components were defined using diagnostic criteria from the International Diabetes Federation.Results
Forty-nine patients (52.7%) had CHF. There was a positive correlation between plasma Nt-proBNP levels and NYHA functional capacity in CHF patients. Plasma Nt-proBNP levels increased significantly with each increasing NYHA class of the disease. The prevalence of metabolic syndrome in CHF patients was higher than that in patients without CHF. Most importantly, we found that plasma Nt-proBNP levels were lower in CHF patients with metabolic syndrome attributable to inverse relationships between plasma Nt-proBNP and body mass index (β = −0.297), plasma triglyceride (β = −0.286) and homeostasis model assessment of insulin resistance (HOMA-IR; β = −0.346). Fasting glucose to insulin ratio (FGIR, an insulin sensitivity index) was positively associated with plasma Nt-proBNP levels (β = 0.491), and was the independent predictor of plasma Nt-proBNP levels in CHF patients.Conclusions
Plasma Nt-proBNP levels are inversely associated with metabolic syndrome in CHF patients. Reduced plasma Nt-proBNP levels in CHF patients may lead to impaired lipolysis and metabolic function, and may contribute to the development of metabolic syndrome in CHF patients. 相似文献36.
Kuei-Chuan Lee Che-Chang Chan Ying-Ying Yang Yun-Cheng Hsieh Yi-Hsiang Huang Han-Chieh Lin 《PloS one》2013,8(10)
Background & Aims
Activation of the renin-angiotensin-system is known to play a role in nonalcoholic steatohepatitis. Renin knockout mice manifest decreased hepatic steatosis. Aliskiren is the first direct renin inhibitor to be approved for clinical use. Our study aims to evaluate the possible therapeutic effects and mechanism of the chronic administration of aliskiren in a dietary steatohepatitis murine model.Methods
Male C57BL/6 mice were fed with a methionine and choline-deficient (MCD) diet to induce steatohepatitis. After 8 weeks of feeding, the injured mice were randomly assigned to receive aliskiren (50 mg·kg-1 per day) or vehicle administration for 4 weeks. Normal controls were also administered aliskiren (50 mg·kg-1 per day) or a vehicle for 4 weeks.Results
In the MCD mice, aliskiren attenuated hepatic steatosis, inflammation and fibrosis. Aliskiren did not change expression of lipogenic genes but increase turnover of hepatic fat by up-regulating peroxisome proliferator-activated receptor α, carnitine palmitoyltransferase 1a, cytochrome P450-4A14 and phosphorylated AMP-activated protein kinase. Furthermore, aliskiren decreased the hepatic expression of angiotensin II and nuclear factor κB. The levels of oxidative stress, hepatocyte apoptosis, activation of Kupffer cells and hepatic stellate cells, and pro-fibrotic markers were also reduced in the livers of the MCD mice receiving aliskiren.Conclusions
Aliskiren attenuates steatohepatitis and fibrosis in mice fed with a MCD diet. Thus, the noted therapeutic effects might come from not only the reduction of angiotensin II but also the up-regulation of fatty acid oxidation-related genes. 相似文献37.
Wei-Chien Huang Yi-Ling Hsieh Chao-Ming Hung Pei-Hsuan Chien Yu-Fong Chien Lei-Chin Chen Chih-Yen Tu Chia-Hung Chen Sheng-Chieh Hsu Yueh-Ming Lin Yun-Ju Chen 《PloS one》2013,8(12)
The multikinase inhibitor, sorafenib (Nexavar®, BAY43-9006), which inhibits both the Raf/MEK/ERK pathway and several receptor tyrosine kinases (RTKs), has shown significantly therapeutic benefits in advanced hepatocellular carcinoma (HCC). However, not all HCC patients respond to sorafenib well and new therapeutic strategies to optimize the efficacy of sorafenib are urgently required. Overexpression of breast cancer resistance protein (BCRP/ABCG2) mediates the drug-efflux of several tyrosine kinase inhibitors (TKIs) to attenuate their efficacy. This study aimed to investigate the role of BCRP/ABCG2 in the sensitivity of HCC to sorafenib. Our data showed that BCRP/ABCG2 mediated the efflux of sorafenib. Co-treatment with a BCRP/ABCG2 inhibitor greatly augmented the cytotoxicity of sorafenib in HCC cells. Similar results were also achieved by the competitive inhibitor of BCRP/ABCG2, gefitinib, in combination with sorafenib. These results suggest not only that BCRP/ABCG2 is a potential predictor for the sorafenib sensitivity in HCC, but also that blockage of BCRP/ABCG2 may be a potential strategy to increase the response of HCC cells to sorafenib. 相似文献
38.
Ming‐Der Wu Ming‐Jen Cheng Yung‐Shun Su Sung‐Yuan Hsieh Hsun‐Shuo Chang Chun‐Wei Chang Gwo‐Fang Yuan 《化学与生物多样性》2013,10(3):493-505
Cultivation of the fungal strain Annulohypoxylon ilanense, an endophytic fungus isolated from the wood of medicinal plant Cinnamomum species, resulted in the isolation of one new furanoid derivative, ilanefuranone ( 1 ), one new pyrrole alkaloid, ilanepyrrolal ( 2 ), and one new biarylpropanoid derivative, ilanenoid ( 3 ), together with 22 known compounds, of which one α‐tetralone analog, (?)‐(4R)‐3,4‐dihydro‐4,6‐dihydroxynaphthalen‐1(2H)‐one ( 4 ) was isolated for the first time from a natural source. The structures were elucidated on the basis of physicochemical evidence, in‐depth NMR spectroscopic analysis, and high‐resolution mass spectrometry, and the antimycobacterial activities were also evaluated. 相似文献
39.
Chia-Ching Liaw Yu-Chen Chen Ahmed Eid Fazary Ju-Liang Hsieh Shun-Ying Chen Ching-Te Chien Shiow-Yunn Sheu Yao-Haur Kuo Bor-Luen Chiang Ya-Ching Shen 《Phytochemistry letters》2013,6(3):397-402
A novel C6–C3 prenylated compound, illicarborene A (1), together with illioliganfunone D (2), 1-allyl-3,5-dimethoxy-4-(3-methylbut-2-enyloxy)benzene (3), (?)-illicinone A (4), (?)-illicinone B (5) and (?)-illicinone A derivative (6) was isolated and characterized from the fruits of Illicium arborescens Hayata. Compound 1 possesses a new class of tricyclic 6/6/5 ring system. The structure of 1 was determined by spectroscopic analysis such as 1H–1H COSY, HMQC, HMBC, and NOESY, and confirmed by chemical reaction to yield 7. Compounds 1–5 were found to increase proliferative activity in primary cell culture of osteoblast cells. 相似文献
40.
Ai-Hsiang Chou Chia-Chyi Liu Jui-Yuan Chang Renee Jiang Yi-Chin Hsieh Amanda Tsao Chien-Long Wu Ju-Lan Huang Chang-Phone Fung Szu-Min Hsieh Ya-Fang Wang Jen-Ren Wang Mei-Hua Hu Jen-Ron Chiang Ih-Jen Su Pele Choi-Sing Chong 《PloS one》2013,8(11)