全文获取类型
收费全文 | 2293篇 |
免费 | 183篇 |
国内免费 | 1篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 29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 | 177篇 |
2012年 | 192篇 |
2011年 | 189篇 |
2010年 | 110篇 |
2009年 | 107篇 |
2008年 | 127篇 |
2007年 | 121篇 |
2006年 | 111篇 |
2005年 | 105篇 |
2004年 | 99篇 |
2003年 | 71篇 |
2002年 | 70篇 |
2001年 | 66篇 |
2000年 | 56篇 |
1999年 | 46篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 7篇 |
1992年 | 26篇 |
1991年 | 40篇 |
1990年 | 25篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1971年 | 4篇 |
1969年 | 5篇 |
排序方式: 共有2477条查询结果,搜索用时 15 毫秒
51.
Muideen Tunbosun Olaiya Hung-Yi Chiou Jiann-Shing Jeng Li-Ming Lien Fang-I Hsieh 《PloS one》2013,8(10)
Objective
To investigate whether gallstone disease (GD) increases the risk of developing cardiovascular disease (CVD) in a large population-based cohort.Methods
A study population including 6,981 patients with GD was identified from The Taiwan National Health Insurance Research Database between 2004 and 2005. GD patients were defined as patients with principal discharge diagnoses of cholelithiasis using the ICD-9-CM code 574. 27,924 patients without GD were randomly selected and matched for age and gender. All patients were followed for 6 years or until diagnosis for CVD. Cox proportional hazards regression model was used to assess the risk of developing CVD with adjustment for age, gender and co-morbid conditions.Results
During the six years follow-up period, 935 patients with GD and 2,758 patients without GD developed CVD. Patients with GD had an elevated risk of CVD (HR, 1.32; 95% CI, 1.22-1.43) when compared with those without GD. Similar relationship was observed when CVD was categorized i.e. stroke (HR, 1.15; 95% CI, 1.01-1.32), coronary heart disease (HR, 1.42; 95% CI, 1.28-1.58) and heart failure (HR, 1.31; 95% CI, 1.00-1.73). When GD was classified according to the level of severity, using patients without GD as reference, the risks of CVD were elevated in patients with non-severe GD (HR, 1.34; 95% CI, 1.24-1.46) as well as those with severe GD (HR, 1.20, 95% CI, 1.02-1.40), after adjusting for age, gender and comorbidities. In age-stratified analysis, patients aged 18-40 years with GD were at higher risk of developing CVD (HR, 1.42; 95% CI, 1.09-1.84) than older GD patients.Conclusion
This study found an increased risk of CVD in patients diagnosed with GD. The excess risk was particularly high in younger GD patients. Prevention of GD could help reduce the risk of developing CVD, and the better effect could be achieved for the younger age groups. 相似文献52.
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53.
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54.
Pei-Ju Liu Yao-Shen Chen Hsi-Hsu Lin Wei-Feng Ni Tsung-Han Hsieh Hsu-Tzu Chen Ya-Lei Chen 《PLoS neglected tropical diseases》2013,7(8)
Background
Approximately 3–5% of patients with melioidosis manifest CNS symptoms; however, the clinical data regarding neurological melioidosis are limited.Methods and Findings
We established a mouse model of melioidosis with meningitis characterized by neutrophil infiltration into the meninges histologically and B. pseudomallei in the cerebrospinal fluid (CSF) by bacteriological culturing methods. As the disease progresses, the bacteria successively colonize the spleen, liver, bone marrow (BM) and brain and invade splenic and BM cells by days 2 and 6 post-infection, respectively. The predominant cell types intracellularly infected with B. pseudomallei were splenic and BM CD11b+ populations. The CD11b+Ly6Chigh inflamed monocytes, CD11b+Ly6Clow resident monocytes, CD11b+Ly6G+ neutrophils, CD11b+F4/80+ macrophages and CD11b+CD19+ B cells were expanded in the spleen and BM during the progression of melioidosis. After adoptive transfer of CD11b populations harboring B. pseudomallei, the infected CD11b+ cells induced bacterial colonization in the brain, whereas CD11b− cells only partially induced colonization; extracellular (free) B. pseudomallei were unable to colonize the brain. CD62L (selectin) was absent on splenic CD11b+ cells on day 4 but was expressed on day 10 post-infection. Adoptive transfer of CD11b+ cells expressing CD62L (harvested on day 10 post-infection) resulted in meningitis in the recipients, but transfer of CD11b+ CD62L-negative cells did not.Conclusions/Significance
We suggest that B. pseudomallei-infected CD11b+ selectin-expressing cells act as a Trojan horse and are able to transmigrate across endothelial cells, resulting in melioidosis with meningitis. 相似文献55.
56.
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
57.
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
58.
Wen-Chih Wu Chih-Hsiung Hsu Jen-Chun Kuan Jih-Fu Hsieh Chien-An Sun Tsan Yang Chang-Chieh Wu Yu-Ching Chou 《Genetics and molecular biology》2013,36(3):323-328
A new noninvasive screening tool for colorectal neoplasia detects epigenetic alterations exhibited by gastrointestinal tumor cells shed into stool. There is insufficient existing data to determine temporal associations between colorectal cancer (CRC) progression and aberrant DNA methylation. To evaluate the feasibility of using fecal DNA methylation status to determine CRC progression, we collected stool samples from 14 male SD rats aged six weeks, and administered subcutaneous injections of either 1,2-dimethylhydrazine or saline weekly. p16 DNA methylation statuses in tumorous and normal colon tissue, and from stool samples were determined using methylation-specific PCR. Additionally, p16 methylation was detected in stool DNA from 85.7% of the CRC rats. The earliest change in p16 methylation status in the DMH-treated group stool samples occurred during week nine; repeatabilities were 57.1% in week 19 (p = 0.070) and 85.7% in week 34 (p = 0.005). A temporal correlation was evidenced between progression of CRC and p16 methylation status, as evidenced by DMH-induced rat feces. Using fecal DNA methylation status to determine colorectal tissue methylation status can reveal CRC progression. Our data suggests that p16 promoter methylation is a feasible epigenetic marker for the detection and may be useful for CRC screening. 相似文献
59.
A new species, Obolarina persica, is described from Iran. It is widely associated with dying Quercus brantii, on which it produces charcoal-like stromata. The fungus described herein differs from the other described species, Ob. dryophila, primarily in its much larger ascospores. 相似文献