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   1664篇
  免费   111篇
  国内免费   19篇
耳鼻咽喉   3篇
儿科学   39篇
妇产科学   21篇
基础医学   205篇
口腔科学   53篇
临床医学   76篇
内科学   594篇
皮肤病学   134篇
神经病学   102篇
特种医学   25篇
外科学   283篇
预防医学   22篇
眼科学   3篇
药学   77篇
中国医学   4篇
肿瘤学   153篇
  2023年   9篇
  2022年   18篇
  2021年   25篇
  2020年   25篇
  2019年   32篇
  2018年   39篇
  2017年   29篇
  2016年   38篇
  2015年   32篇
  2014年   52篇
  2013年   51篇
  2012年   89篇
  2011年   132篇
  2010年   68篇
  2009年   45篇
  2008年   88篇
  2007年   131篇
  2006年   125篇
  2005年   130篇
  2004年   113篇
  2003年   112篇
  2002年   112篇
  2001年   22篇
  2000年   19篇
  1999年   20篇
  1998年   31篇
  1997年   30篇
  1996年   28篇
  1995年   22篇
  1994年   8篇
  1993年   9篇
  1992年   8篇
  1991年   11篇
  1990年   12篇
  1989年   11篇
  1988年   14篇
  1987年   3篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1980年   4篇
  1979年   3篇
  1978年   3篇
  1977年   5篇
  1974年   2篇
  1957年   1篇
  1956年   2篇
  1955年   4篇
  1954年   3篇
排序方式: 共有1794条查询结果,搜索用时 31 毫秒
61.
Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG-IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG-IFNα-2b/RBV and quantified expressions of viral sensors (RIG-I, MDA5, and LGP2), adaptor molecule (IPS-1), related ubiquitin E3-ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up-regulated compared with that in IL28B major patients (≈ 3.3-fold, P < 0.001). However, expression of IPS-1 was significantly lower in IL28B minor patients (1.2-fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈ 2.6-fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG-I and ISG15 expressions and RIG-I/IPS-1 expression ratio were independent factors for NVR. IPS-1 down-regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS-1 protein cleavage was associated with the variable treatment response. CONCLUSION: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG-IFNα/RBV. Both IL28B minor allele and higher RIG-I and ISG15 expressions and RIG-I/IPS-1 ratio are independent factors for NVR.  相似文献   
62.
63.
64.
Aim: To evaluate the usefulness of a modified technique of endoscopic papillectomy (EP) for lessening the occurrence of complications. Methods: Indications for EP were adenoma or well‐differentiated adenocarcinoma confined to the papilla of Vater (T1) without tumor spread into the bile/pancreatic duct. Sixteen patients underwent the modified technique, which consists of resection with the Endocut® mode, followed by biliary/pancreatic sphincterotomy and stenting (Group A). Twelve patients who had undergone EP, using a cutting current, followed by pancreatic duct stenting were included as control (Group B). The frequency of complications and clinical outcomes were retrospectively compared between the two groups. Results: Sixteen patients had adenoma, and 12 had adenocarcinoma. Early complications occurred in 36% of all patients (hemorrhage, 7; cholangitis, 3; perforation, 2; cholecystitis, 1). The frequency of early complications in Group A was significantly lower than that in Group B (6% vs 75%, odds ratio [OR] 0.022, 95% confidence interval [CI], 0.0020–0.25). Late complications occurred in 18% of the patients (bile duct stone, 3; hemorrhage, 1; pancreatitis, 1). There was no significant difference in the late complication rate between Group A and Group B (19% vs 17%). Local recurrences were found in 14% of the patients, without a significant difference between Group A and Group B (19% vs 8%) during a mean follow‐up period. All recurrent tumors were successfully treated with argon plasma coagulation. Conclusions: The modified technique of EP for ampullary neoplasm contributed to lessening the occurrence of early complications. However, further refinement of this technique is necessary for improving the clinical outcome.  相似文献   
65.
CD147 is a glycosylated membrane protein that belongs to the immunoglobulin superfamily. This study aimed to determine serum soluble CD147 (sCD147) levels and their clinical associations in patients with systemic sclerosis (SSc). Serum sCD147 levels were examined by enzyme-linked immunosorbent assay in 61 SSc patients and 24 healthy individuals. Serum sCD147 levels were significantly elevated in SSc patients compared with healthy individuals (P < 0.001). Among patients with SSc, there were no differences in serum sCD147 levels between limited cutaneous (n = 30) and diffuse cutaneous SSc (n = 31). Patients with SSc who had elevated sCD147 levels had renal crisis more often than those with normal sCD147 levels (13% vs 0%; P < 0.05). Serum sCD147 levels were increased in patients with SSc and associated with the presence of renal crisis. These results suggest that sCD147 may have a role in the development of renal crisis in SSc. Measurement of serum sCD147 may be useful for risk stratification for renal crisis in SSc.  相似文献   
66.
Intravenous cyclophosphamide pulse therapy (IVCY) exerts its efficacy against interstitial lung disease (ILD) associated with systemic sclerosis (SSc) by restoring vascular injuries as well as aberrant immune activation. We recently experienced two patients with SSc-ILD in whom the values of brachial flow-mediated dilation (FMD) reflected the efficacy of IVCY. We herein report the details of these cases and discuss the potential of FMD to predict and evaluate the effect of IVCY on SSc-ILD.  相似文献   
67.

Background

Right ventricular myocardial infarction (RVMI) is a complication of acute inferior myocardial infarction and sometimes causes severe hemodynamic disturbance. It is therefore important to promptly detect RVMI and assess the severity of right ventricular (RV) dysfunction. Tissue Doppler imaging (TDI) is a useful method to assess left ventricular function and RV function. In this study, we investigated the possibility of diagnosing RVMI using tricuspid annular velocity determined by TDI.

Methods

Thirty consecutive patients with first acute inferior myocardial infarction were studied. The diagnosis of RVMI was based on an ST-segment elevation of at least 0.1 mV in lead V4R. The patients were classified into 12 patients with RVMI (the RVMI group) and 18 patients without RVMI (non-RVMI group). All patients underwent two-dimensional echocardiography, pulsed Doppler and TDI, and coronary angiography within 48 h after onset of myocardial infarction. Tricuspid inflow velocity was recorded by pulsed Doppler and early diastolic tricuspid inflow velocity (TVE) was measured. Peak early diastolic velocity of the tricuspid annulus (TVe’) at the RV free wall was recorded using TDI. The ratio of TVE to TVe’ (TVE/TVe’) was calculated.

Results

TVe’ was significantly lower in the RVMI group compared to that in the non-RVMI group (5.9 ± 1.3 vs. 9.1 ± 3.1; p = 0.0025). On the basis of a TVe’ cutoff value of less than 8.3 cm/s, RVMI was diagnosed with 100 % sensitivity and 61 % specificity.

Conclusions

The early diastolic tricuspid annular velocity determined by TDI is a noninvasive and sensitive index for diagnosing RVMI.  相似文献   
68.
Annals of Nuclear Medicine - Radium-223 dichloride (Ra-223) is the first targeted alpha therapy approved for the treatment of patients with castration-resistant prostate cancer (CRPC) with bone...  相似文献   
69.

Background

Targeting the modifiable risk factors may help halt the progression of CKD, thus risk factor analysis is better performed using the parameters in the follow-up. This study aimed to examine the time-dependent risk factors for CKD progression using time-averaged values and to investigate the characteristics of rapid progression group.

Methods

This is a retrospective cohort study enrolling 770 patients of CKD stage 3–4. Time-dependent parameters were calculated as time-averaged values by a trapezoidal rule. % decline of estimated GFR (eGFR) per year from entry was divided to three groups: <10 % (stable), 10–25 % (moderate progression), and ≥25 % (rapid progression). Multivariate regression analyses were employed for the baseline and the time-averaged datasets.

Results

eGFR decline was 2.83 ± 4.04 mL/min/1.73 m2/year (8.8 ± 12.9 %) in male and 1.66 ± 3.23 mL/min/1.73 m2/year (5.4 ± 11.0 %) in female (p < 0.001). % decline of eGFR was associated with male, proteinuria, phosphorus, and systolic blood pressure as risk factors and with age, albumin, and hemoglobin as protective factors using either dataset. Baseline eGFR and diabetic nephropathy appeared in the baseline dataset, while uric acid appeared in the time-averaged dataset. The rapid progression group was associated with proteinuria, phosphorus, albumin, and hemoglobin in the follow-up.

Conclusion

These results suggest that time-averaged values provide insightful clinical guide in targeting the risk factors. Rapid decline of eGFR is strongly associated with hyperphosphatemia, proteinuria, and anemia indicating that these risk factors should be intervened in the follow-up of CKD.
  相似文献   
70.
Previous in vivo studies including those with knockout mice suggested that Niemann-Pick C1-like 1 (NPC1L1) plays an essential role in the intestinal absorption of cholesterol. To characterize the mechanism of cholesterol uptake mediated by NPC1L1, an in vitro system reflecting the function of this transporter needs to be established. In the present study, we constructed NPC1L1 overexpressing CaCo-2 cells as an in vitro model and characterized the transport properties of NPC1L1. Immunohistochemical staining revealed that CaCo-2 cells express NPC1L1 on the apical membrane. It was also demonstrated that the uptakes of both cholesterol and beta-sitosterol are increased by NPC1L1 overexpression. In addition, the uptake of cholesterol was increased in a dose-dependent manner by an increase in the content of taurocholate in micelles, whereas micellar phosphatidylcholine showed a negative correlation with cholesterol uptake. Furthermore, it was confirmed that sterol uptake increased by NPC1L1 overexpression was inhibited by ezetimibe. We could thus establish an in vitro intestinal model to study the mechanism of NPC1L1-dependent sterol uptake and to screen drug candidates whose target is NPC1L1.  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