首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8076篇
  免费   299篇
  国内免费   47篇
耳鼻咽喉   203篇
儿科学   210篇
妇产科学   441篇
基础医学   1253篇
口腔科学   102篇
临床医学   450篇
内科学   1904篇
皮肤病学   188篇
神经病学   610篇
特种医学   207篇
外国民族医学   1篇
外科学   786篇
综合类   51篇
一般理论   1篇
预防医学   467篇
眼科学   195篇
药学   846篇
中国医学   42篇
肿瘤学   465篇
  2023年   33篇
  2022年   114篇
  2021年   195篇
  2020年   72篇
  2019年   102篇
  2018年   183篇
  2017年   161篇
  2016年   176篇
  2015年   212篇
  2014年   313篇
  2013年   389篇
  2012年   604篇
  2011年   625篇
  2010年   321篇
  2009年   240篇
  2008年   464篇
  2007年   493篇
  2006年   535篇
  2005年   495篇
  2004年   521篇
  2003年   472篇
  2002年   442篇
  2001年   187篇
  2000年   194篇
  1999年   119篇
  1998年   45篇
  1997年   31篇
  1996年   22篇
  1995年   23篇
  1994年   21篇
  1993年   16篇
  1992年   24篇
  1991年   31篇
  1990年   28篇
  1989年   20篇
  1988年   34篇
  1987年   30篇
  1986年   29篇
  1985年   33篇
  1984年   24篇
  1983年   23篇
  1982年   24篇
  1981年   16篇
  1979年   29篇
  1978年   19篇
  1977年   24篇
  1975年   38篇
  1974年   19篇
  1973年   19篇
  1971年   22篇
排序方式: 共有8422条查询结果,搜索用时 15 毫秒
101.
102.

Background

Metabolic syndrome has clinical implications for chronic liver disease, but the relationship between chronic hepatitis B and metabolic syndrome remains unclear. The aim of this study was to determine whether hepatitis B surface antigen (HBsAg) positivity is associated with metabolic syndrome.

Methods

Data were obtained from the Third Korean National Health and Nutrition Examination Survey (KNHANES). Participant sera were tested for HBsAg. Metabolic syndrome was defined according to the modified National Cholesterol Education Program Adult Treatment Panel III guidelines for Koreans.

Results

Of the 5108 participants, 209 (4.1%) tested positive for HBsAg, and 1364 (26.7%) were diagnosed with metabolic syndrome. The prevalence of metabolic syndrome was 23.4% in HBsAg-positive men, 31.5% in HBsAg-negative men, 18.6% in HBsAg-positive women, and 23.7% in HBsAg-negative women. After adjusting for multiple factors, male participants who tested positive for serum HBsAg had an odds ratio of 0.612 (95% confidence interval [CI] 0.375–0.998) for metabolic syndrome and an odds ratio of 0.631 (95% CI 0.404–0.986) for elevated triglycerides. Women who tested positive for serum HBsAg had an odds ratio of 0.343 (95% CI 0.170–0.693) for elevated triglycerides.

Conclusions

Positive results for serum HBsAg are inversely associated with metabolic syndrome in men and with elevated triglycerides in men and women. This suggests that elevated triglycerides may contribute to the inverse association between HBsAg and metabolic syndrome.Key words: chronic hepatitis B, metabolic syndrome, survey, triglycerides  相似文献   
103.
Purpose

The aim of the study was to assess the effectiveness of Superb Micro-vascular Imaging (SMI) as an alternative to Contrast-Enhanced Ultrasound (CEUS) and Computed Tomography Angiography (CTA) for endoleak detection and classification in patients followed up after endovascular abdominal aortic aneurysm repair (EVAR).

Materials and methods

From May 2015 to January 2017, 30 patients underwent post-EVAR follow-up with Color Doppler Ultrasound (CDUS), CEUS, SMI, and CTA examinations. Aneurysmal sac diameter and graft patency were evaluated; endoleaks were identified and classified. Sensitivity, specificity, and accuracy values were calculated for each of the four diagnostic methods of endoleak detection. A percentage of agreement and Cohen’s Kappa coefficient were calculated for comparison of methods in terms of endoleak identification.

Results

CTA revealed fifteen endoleaks (50%): three type Ia, nine type II, and three type III. The sensitivity of CDUS, CEUS, and SMI relative to CTA was 27%, 100%, and 100%, respectively. Specificity was 93%, 93%, and 93%, respectively. Accuracy was 60%, 97%, and 97%, respectively. There were no differences between SMI and CEUS in terms of sensitivity, specificity, or accuracy (100%, 93%, and 97%). We do not observe statistically significant differences between CTA, CEUS, and SMI concerning endoleak identification ability. The weakest method in endoleak identification was CDUS.

Conclusions

The analysis showed that SMI is effective, repeatable, and comparable with the CEUS modality in identification endoleaks after EVAR; it may be considered as a potential tool to monitor patients after EVAR implantation, especially those with renal insufficiency or with an allergy to any contrast media.

  相似文献   
104.
Preclinical Research
A series of phosphate and thiophosphate flavone derivatives were synthesized and biologically evaluated in vitro for inhibition of steroid sulfatase (STS) activity. The described synthesis includes the straightforward preparation of 7‐hydroxy‐2‐phenyl‐4H‐chromen‐4‐one 3a, 2‐(4‐fluorophenyl)‐7‐hydroxy‐4H‐chromen‐4‐one 3b, 7‐hydroxy‐2‐(4‐(trifluoromethyl)phenyl)‐4H‐chromen‐4‐one 3c, 7‐hydroxy‐2‐(p‐tolyl)‐4H‐chromen‐4‐one 3d modified with different phosphate or thiophosphate moieties. The inhibitory properties of the synthesized compounds were tested against human placenta STS. Some of the novel STS inhibitors had good activities against STS. In particular, the bis‐(4‐oxo‐2‐(p‐tolyl)‐4H‐chromen‐7‐yl) hydrogenthiophosphate, 6i had the most potent inhibitory effect with an IC50 value of 3.25 µM as compared to an IC50 value of 8.50 µM for the 2‐(4‐trifluoromethylphenyl)‐chromen‐4‐one‐7‐O‐sulfamate used as a reference. Drug Dev Res 76 : 450–462, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
105.
106.
107.
The detailed mechanisms determining the course of congestive heart failure (CHF) in hypertensive subjects with associated renal dysfunction remain unclear. In Ren‐2 transgenic rats (TGR), a model of angiotensin II (ANG II)‐dependent hypertension, CHF was induced by volume overload achieved by creation of the aorto‐caval fistula (ACF). In these rats we investigated the putative pathophysiological contribution of epoxyeicosatrienoic acids (EETs) and compared it with the role of the renin‐angiotensin system (RAS). We found that untreated ACF TGR exhibited marked intrarenal and myocardial deficiency of EETs and impairment of renal function. Chronic treatment of these rats with cis‐4‐[4‐(3‐adamantan‐1‐yl‐ureido)cyclohexyloxy]benzoic acid (c‐AUCB, 3 mg/L in drinking water), an inhibitor of soluble epoxide hydrolase (sEH) which normally degrades EETs, increased intrarenal and myocardial EETs, markedly improved survival rate, and increased renal blood flow, glomerular filtration rate and fractional sodium excretion, without altering RAS activity. Chronic angiotensin‐converting enzyme inhibition (ACEi) with trandolapril, (6 mg/L in drinking water) improved survival rate even more, and also inhibited the development of renal dysfunction; these beneficial actions were associated with significant suppression of the vasoconstrictor/sodium retaining axis and further activation of the vasodilatory/natriuretic axis of the systemic and intrarenal RAS, without modifying tissue availability of biologically active fatty acid epoxides. In conclusion, these findings strongly suggest that chronic sEH inhibition and chronic treatment with ACEi, each of them altering a different vasoactive system, delay or even prevent the onset of decompensation of CHF in ACF TGR, probably by preventing the development of renal dysfunction.  相似文献   
108.
Journal of Gastroenterology - The overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS) is associated with more severe gastrointestinal (GI) symptoms and lower quality of...  相似文献   
109.
110.
A 65 year old man with low grade malignant B cell lymphoma developed bilateral chylothorax, which reached the volume of 52.1. Chylothorax arised most probably as a result of pleural infiltration in the course of the disease. Chemotherapy and repeated drainage of chylus was successful. The resolution of massive bilateral chylothorax in our patient shows, that conservative measures (chemotherapy and repeated pleural drainage) should be tried even in very extensive chylothorax in the course of neoplastic disease.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号