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   37510篇
  免费   2578篇
  国内免费   2869篇
耳鼻咽喉   24篇
儿科学   548篇
妇产科学   123篇
基础医学   2597篇
口腔科学   34篇
临床医学   4443篇
内科学   11424篇
皮肤病学   160篇
神经病学   215篇
特种医学   2690篇
外科学   8040篇
综合类   4610篇
预防医学   1545篇
眼科学   21篇
药学   2908篇
  12篇
中国医学   1249篇
肿瘤学   2314篇
  2024年   48篇
  2023年   513篇
  2022年   1156篇
  2021年   1427篇
  2020年   1247篇
  2019年   1097篇
  2018年   1123篇
  2017年   965篇
  2016年   1219篇
  2015年   1372篇
  2014年   2612篇
  2013年   2253篇
  2012年   2384篇
  2011年   2465篇
  2010年   2272篇
  2009年   2335篇
  2008年   2376篇
  2007年   2303篇
  2006年   2199篇
  2005年   1791篇
  2004年   1256篇
  2003年   1114篇
  2002年   1008篇
  2001年   882篇
  2000年   751篇
  1999年   610篇
  1998年   538篇
  1997年   488篇
  1996年   414篇
  1995年   391篇
  1994年   378篇
  1993年   271篇
  1992年   242篇
  1991年   183篇
  1990年   152篇
  1989年   149篇
  1988年   135篇
  1987年   90篇
  1986年   80篇
  1985年   90篇
  1984年   66篇
  1983年   39篇
  1982年   62篇
  1981年   63篇
  1980年   47篇
  1979年   41篇
  1978年   52篇
  1977年   37篇
  1976年   35篇
  1974年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
ObjectivesThe aim of this meta-analysis was to conduct a contemporary systematic review of high quality non-randomised controlled trials to determine the effect of pre-liver transplantation (LT) transarterial chemoembolisation (TACE) on long-term survival and complications of hepatocellular carcinoma (HCC) patients.BackgroundTACE is used as a neoadjuvant therapy to mitigate waitlist drop-out for patients with HCC awaiting LT. Previous studies have conflicting conclusions on the effect of TACE on long-term survival and complications of HCC patients undergoing LT.MethodsCINAHL, Cochrane Controlled Register of Trials, Embase, PubMed, and Web of Science were systematically searched. Baseline characteristics included number of patients outside Milan criteria, tumour diameter, MELD score, and time on the waiting list. Primary outcomes included 3- and 5-year overall and disease-free survival. Secondary outcomes included tumour recurrence, 30-day postoperative mortality, and hepatic artery and biliary complications.ResultsTwenty-one high-quality NRCTs representing 8242 patients were included. Tumour diameter was significantly larger in TACE patients (3.49 cm vs 3.15 cm, P = 0.02) and time on the waiting list was significantly longer in TACE patients (4.87 months vs 3.46 months, P = 0.05), while MELD score was significantly higher in non-TACE patients (10.81 vs 12.35, P = 0.005). All primary and secondary outcomes displayed non-significant differences.ConclusionPatients treated with TACE had similar survival and postoperative outcomes to non-TACE patients, however, they had worse prognostic features compared to non-TACE patients. These findings strongly support the current US and European clinical practice guidelines that neoadjuvant TACE can be used for patients with longer expected waiting list times (specifically >6 months). Randomised controlled trials would be needed to increase the quality of evidence.  相似文献   
2.
BackgroundLiver resection is commonly performed for hepatic tumors, however preoperative risk stratification remains challenging. We evaluated the performance of contemporary prediction models for short-term mortality after liver resection in patients with and without cirrhosis.MethodsThis retrospective cohort study examined National Surgical Quality Improvement Program data. We included patients who underwent liver resections from 2014 to 2019. VOCAL-Penn, MELD, MELD-Na, ALBI, and Mayo risk scores were evaluated in terms of model discrimination and calibration for 30-day post-operative mortality.ResultsA total 15,198 patients underwent liver resection, of whom 249 (1.6%) experienced 30-day post-operative mortality. The VOCAL-Penn score had the highest discrimination (area under the ROC curve [AUC] 0.74) compared to all other models. The VOCAL-Penn score similarly outperformed other models in patients with (AUC 0.70) and without (AUC 0.74) cirrhosis.ConclusionThe VOCAL-Penn score demonstrated superior predictive performance for 30-day post-operative mortality after liver resection as compared to existing clinical standards.  相似文献   
3.
The circadian rhythm in humans is determined by the central clock located in the hypothalamus’s suprachiasmatic nucleus, and it synchronizes the peripheral clocks in other tissues. Circadian clock genes and clock-controlled genes exist in almost all cell types. They have an essential role in many physiological processes, including lipid metabolism in the liver, regulation of the immune system, and the severity of infections. In addition, circadian rhythm genes can stimulate the immune response of host cells to virus infection. Hepatitis B virus (HBV) infection is the leading cause of liver disease and liver cancer globally. HBV infection depends on the host cell, and hepatocyte circadian rhythm genes are associated with HBV replication, survival, and spread. The core circadian rhythm proteins, REV-ERB and brain and muscle ARNTL-like protein 1, have a crucial role in HBV replication in hepatocytes. In addition to influencing the virus’s life cycle, the circadian rhythm also affects the pharmacokinetics and efficacy of antiviral vaccines. Therefore, it is vital to apply antiviral therapy at the appropriate time of day to reduce toxicity and improve the effectiveness of antiviral treatment. For these reasons, understanding the role of the circadian rhythm in the regulation of HBV infection and host responses to the virus provides us with a new perspective of the interplay of the circadian rhythm and anti-HBV therapy. Therefore, this review emphasizes the importance of the circadian rhythm in HBV infection and the optimization of antiviral treatment based on the circadian rhythm-dependent immune response.  相似文献   
4.
Over the last 40 years, the incidence and prevalence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have continued to increase. Compared to other epithelial neoplasms in the same organ, GEP-NENs exhibit indolent biological behavior, resulting in more chances to undergo surgery. However, the role of surgery in high-grade or advanced GEP-NENs is still controversial. Surgery is associated with survival improvement of well-differentiated high-grade GEP-NENs, whereas poorly differentiated GEP-NENs that may benefit from resection require careful selection based on Ki67 and other tissue biomarkers. Additionally, surgery also plays an important role in locally advanced and metastatic disease. For locally advanced GEP-NENs, isolated major vascular involvement is no longer an absolute contraindication. In the setting of metastatic GEP-NENs, radical intended surgery is recommended for patients with low-grade and resectable metastases. For unresectable metastatic disease, a variety of surgical approaches, including cytoreduction of liver metastasis, liver transplantation, and surgery after neoadjuvant treatment, show survival benefits. Primary tumor resection in GEP-NENs with unresectable metastatic disease is associated with symptom control, prolonged survival, and improved sensitivity toward systemic therapies. Although there is no established neoadjuvant or adjuvant strategy, increasing attention has been given to this emerging research area. Some studies have reported that neoadjuvant therapy effectively reduces tumor burden, improves the effectiveness of subsequent surgery, and decreases surgical complications.  相似文献   
5.
《Cirugía espa?ola》2022,100(7):437-439
Complete liver mobilization for major resections sometimes causes liver tilting due to the release of the suspensory elements of the liver. Rarely this may take to a liver abnormal position with acute obstruction to venous flow at the suprahepatic level (Budd-Chiari syndrome). To avoid this complication, techniques such as post-operative stent implantation have been described. The case of a patient who underwent a complete mobilization of the liver for resection of the inferiour venous cava and a right renal tumor, was reported. After that, an acute Budd-Chiari Syndrome was observed caused of the liver malposition, which was solved with the placement of two silicone prostheses in the liver cell.  相似文献   
6.
目的  探讨Hsa-miR-4282在肝癌细胞系SMMC-7721中的表达及其对细胞生长的影响。方法 采用实时荧光定量PCR法检测Hsa-miR-4282在人正常肝上皮细胞系HL-7702和人肝癌细胞系MHCC97-H、SMMC-7721,以及 20例肝癌组织及其相应癌旁组织中的表达。采用瞬时转染法将Hsa-miR-4282 mimics(上调组)和Hsa-miR-4282 inhibitor(下调组)分别转染肝癌SMMC-7721细胞,上调组和下调组分别设置相应阴性对照组。转染后采用MTT法检测细胞增殖能力,平板克隆形成实验检测细胞克隆形成能力,流式细胞仪检测细胞凋亡能力。结果 Hsa-miR-4282在肝癌组织、肝癌细胞MHCC97-H及肝癌细胞SMMC-7721中的表达均低于癌旁组织及正常肝细胞HL-7702(P<0.05)。MTT实验结果显示,Hsa-miR-4282上调后肝癌SMMC-7721细胞的OD值低于其阴性对照组,而下调后OD值高于其阴性对照组 (P<0.05)。平板克隆形成实验显示,下调组的细胞克隆数高于其阴性对照组[(240±7) 个 vs (191±10) 个,P=0.005)],而上调组细胞克隆数低于基阴性对照组[(146±10) 个 vs (193±12) 个,P=0.013)]。流式细胞仪检测结果显示,Hsa-miR-4282上调组细胞凋亡率较其阴性对照组升高[(23.89±1.89)% vs(16.6±1.14)%,P=0.009)],下调组细胞凋亡率较期阴性对照组降低[(14.98±0.46)% vs (17.79±0.73)%,P=0.010]。结论 Hsa-miR-4282上调可抑制肝癌SMMC-7721细胞增殖,促进细胞凋亡,可能与肝癌的发病机制有关。  相似文献   
7.
Rhabdomyolysis is a syndrome of skeletal muscle injury with release of cellular constituents such as potassium,phosphate,urate and intracellular proteins such as myoglobin into the circulation,which may cause complications including acute kidney injury,electrolyte disturbance and cardiac instability.Abnormal liver function tests are frequently observed in cases of severe rhabdomyolysis.Typically,there is an increase in serum aminotransferases,namely aspartate aminotransferase and alanine aminotransferase.This raises the question of liver injury and often triggers a pathway of investigation which may lead to a liver biopsy.However,muscle can also be a source of the increased aminotransferase activity.This review discusses the dilemma of finding abnormal liver function tests in the setting of muscle injury and the potential implications of such an association.It delves into some of the clinical and experimental evidence for correlating muscle injury to raised aminotransferases,and discusses pathophysiological mechanisms such as oxidative stress which may cause actual liver injury.Serum aminotransferases lack tissue specificity to allow clinicians to distinguish primary liver injury from muscle injury.This review also explores potential approaches to improve the accuracy of our diagnostic tools,so that excessive or unnecessary liver investigations can be avoided.  相似文献   
8.
BACKGROUND Postoperative liver failure is the most severe complication in cirrhotic patients with hepatocellular carcinoma(HCC) after major hepatectomy. Current available clinical indexes predicting postoperative residual liver function are not sufficiently accurate.AIM To determine a radiomics model based on preoperative gadoxetic acid-enhanced magnetic resonance imaging for predicting liver failure in cirrhotic patients with HCC after major hepatectomy.METHODS For this retrospective study, a radiomics-based model was developed based on preoperative hepatobiliary phase gadoxetic acid-enhanced magnetic resonance images in 101 patients with HCC between June 2012 and June 2018. Sixty-one radiomic features were extracted from hepatobiliary phase images and selected by the least absolute shrinkage and selection operator method to construct a radiomics signature. A clinical prediction model, and radiomics-based model incorporating significant clinical indexes and radiomics signature were built using multivariable logistic regression analysis. The integrated radiomics-based model was presented as a radiomics nomogram. The performances of clinical prediction model, radiomics signature, and radiomics-based model for predicting post-operative liver failure were determined using receiver operating characteristics curve, calibration curve, and decision curve analyses.RESULTS Five radiomics features from hepatobiliary phase images were selected to construct the radiomics signature. The clinical prediction model, radiomics signature, and radiomics-based model incorporating indocyanine green clearance rate at 15 min and radiomics signature showed favorable performance for predicting postoperative liver failure(area under the curve: 0.809-0.894). The radiomics-based model achieved the highest performance for predicting liver failure(area under the curve: 0.894; 95%CI: 0.823-0.964). The integrated discrimination improvement analysis showed a significant improvement in the accuracy of liver failure prediction when radiomics signature was added to the clinical prediction model(integrated discrimination improvement = 0.117, P =0.002). The calibration curve and an insignificant Hosmer-Lemeshow test statistic(P = 0.841) demonstrated good calibration of the radiomics-based model. The decision curve analysis showed that patients would benefit more from a radiomics-based prediction model than from a clinical prediction model and radiomics signature alone.CONCLUSION A radiomics-based model of preoperative gadoxetic acid–enhanced MRI can be used to predict liver failure in cirrhotic patients with HCC after major hepatectomy.  相似文献   
9.
10.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  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