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   4331篇
  免费   166篇
  国内免费   23篇
耳鼻咽喉   217篇
儿科学   119篇
妇产科学   122篇
基础医学   524篇
口腔科学   16篇
临床医学   340篇
内科学   1231篇
皮肤病学   70篇
神经病学   350篇
特种医学   82篇
外科学   450篇
综合类   34篇
一般理论   2篇
预防医学   231篇
眼科学   122篇
药学   402篇
中国医学   2篇
肿瘤学   206篇
  2023年   25篇
  2022年   145篇
  2021年   249篇
  2020年   70篇
  2019年   88篇
  2018年   125篇
  2017年   95篇
  2016年   83篇
  2015年   95篇
  2014年   140篇
  2013年   215篇
  2012年   324篇
  2011年   375篇
  2010年   177篇
  2009年   133篇
  2008年   260篇
  2007年   291篇
  2006年   300篇
  2005年   303篇
  2004年   281篇
  2003年   239篇
  2002年   214篇
  2001年   21篇
  2000年   19篇
  1999年   13篇
  1998年   23篇
  1997年   15篇
  1996年   14篇
  1995年   8篇
  1994年   14篇
  1993年   11篇
  1992年   9篇
  1991年   11篇
  1990年   5篇
  1989年   8篇
  1988年   5篇
  1987年   7篇
  1986年   9篇
  1985年   9篇
  1984年   5篇
  1983年   6篇
  1982年   10篇
  1980年   7篇
  1978年   8篇
  1977年   11篇
  1976年   4篇
  1975年   4篇
  1971年   6篇
  1970年   5篇
  1968年   4篇
排序方式: 共有4520条查询结果,搜索用时 15 毫秒
141.
Background: Early identified factors determining overweight and obesity in childhood may be important for preventive purposes.

Aim: To evaluate the influence of the commonly accepted and hypothetical risk factors for overweight/obesity and their mutual relations, using the method of classification trees.

Subjects and methods: The data were collected during anthropometric surveys carried out in 2010 in Kraków, Poland. The study involved 1042 pre-school children aged 3–7?years. BMI was calculated for all subjects classified as underweight, normal body weight and overweight, according to the IOTF cut-offs. In order to determine the correlation between genetic, environmental and lifestyle factors and the child’s BMI, this study used information from a questionnaire filled in by the mothers.

Results: Relatively high birth weights, relatively long times of breastfeeding and father’s obesity were conducive to the appearance of overweight and obesity in boys. Other overweight risk factors included alcohol consumption by the mother, her low education level and a relatively low mother’s age at birth. Among girls, factors leading to overweight included high birth weight, high father’s BMI and family situation reported as below very good by their mothers. It was found that a moderate duration of breastfeeding is conducive to a normal weight of children at pre-school age, although in boys this regularity is better documented.

Conclusions: The biological, social and lifestyle factors related to the child’s mother significantly determined the child’s BMI.  相似文献   
142.

Introduction

Early atherosclerotic changes in the endothelium associated with metabolic syndrome are generated with the participation of inflammatory cells, cytokines and enzymes of the extracellular matrix. The study is aimed at a comparison between the activity of inflammatory agents, tumour necrosis factor α (TNF-α) and the enzymes of the connective tissue matrix in the blood of healthy female patients as well as those suffering from the metabolic syndrome.

Material and methods

The examination included 35 women with metabolic syndrome (MS). The control group (C) comprised 35 healthy women. Lipidogram, C-reactive protein level (CRP), fasting glucose level (FGL), matrix metalloproteinase (MMP)-8 and -9 activity, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TNF-α levels in blood were determined.

Results

As compared with the control group, the level of inflammatory factors and the activity of extracellular matrix enzymes in the metabolic syndrome were statistically higher (p < 0.05) and concerned the following parameters: TNF-α (pg/ml): MS 6.59 ±3.18, C 4.78 ±2.91; CRP (mg/dl): MS 2.18 ±2.04, C 1,26 ±1.35; TIMP-1 (ng/ml): MS 265.5 ±2.9, C 205.4 ±72.6; MMP-9 (ng/ml): MS 198.2 ±138.6, C 138.6 ±116.1. Statistically significant correlations were also found between TIMP-1 and the following factors: BMI (R = 0.400, p < 0.001), waist/hip ratio (WHR) (R = 0.278, p < 0.05), waistline (R = 0.417, p < 0.001), FGL (R = 0.290, p < 0.05), HDL cholesterol (R = –0.253, p < 0.05) and triglycerides (R = 0.269, p < 0.05).There were positive correlations of MMP-9 with FGL (R = 0.446, p < 0.001) and waistline (R = 0.260, p < 0.05); MMP-8 with FGL (R = 0.308, p < 0.05); and CRP with BMI (R = 0.370, p < 0.01), WHR (R = 0.325, p < 0.01) and waistline (R = 0.368, p < 0.01).

Conclusions

Metabolic syndrome is connected with higher activity of cytokines (TNF-α), inflammatory markers (CRP) and matrix enzymes (MMP-9, MMP-8, TIMP-1).  相似文献   
143.
Citation Basta P, Galazka K, Mach P, Jozwicki W, Walentowicz M, Wicherek L. The immunohistochemical analysis of RCAS1, HLA‐G, and B7H4‐positive macrophages in partial and complete hydatidiform mole in both applied therapeutic surgery and surgery followed by chemotherapy. Am J Reprod Immunol 2011; 65: 164–172 Introduction The suppressive microenvironment developing around the implantating ovum in normal pregnant women may correlate with the development in cancer patients of a suppressive microenvironment of neoplasmatic cells derived from trophoblasts, such as occurs in molar lesions. Macrophages are suitable candidates for mediating not only the balance of the maternal defensive immune responses to external antigens, but also a tolerance to tumor cells. The aim of our study has been to gain information about the expression of RCAS1, B7H4, and HLA‐G within the macrophages present in the microenvironment of the molar lesion. Methods We analyzed the immunoreactivity of such antigens as B7H4, RCAS1, and HLA‐G on the macrophages present in tissue samples derived from patients on whom curettage was performed after a diagnosis of molar pregnancy. These patients were then divided into two subgroups according to whether or not they required chemotherapy after the surgical procedure. Results We observed a statistically significant increase in the RCAS1‐positive macrophage infiltration within the microenvironment of the molar lesions in patients with partial hydatidiform mole in comparison with those patients who exhibited complete hydatidiform mole. There were no such differences, however, in the infiltration of HLA‐G‐ and B7H4‐positive macrophages between the two groups of patients. Additionally, we showed that RCAS1‐ and HLA‐G‐positive macrophages are more distinct in those cases of complete molar pregnancy where chemotherapy was necessary after surgical treatment while no such differences with respect to B7H4‐positive macrophages were observed. Conclusion The immune‐suppressive endometrial microenvironment represented by suppressive macrophages may have an influence on the clinical course of hydatidiform mole.  相似文献   
144.
The mechanisms initiating eosinophil influx into sites of inflammation have been well studied in allergic disease but are poorly understood in other settings. This study examined the roles of TLR2 and mast cells in eosinophil accumulation during a nonallergic model of eosinophilia-associated colitis. TLR2-deficient mice (TLR2(-/-)) developed a more severe colitis than wild-type mice in the dextran sodium sulfate (DSS) model. However, they had significantly fewer eosinophils in the submucosa of the cecum (P < 0.01) and mid-colon (P < 0.01) than did wild-type mice after DSS treatment. Decreased eosinophilia in TLR2(-/-) mice was associated with lower levels of cecal CCL11 (P < 0.01). Peritoneal eosinophils did not express TLR2 protein, but TLR2 ligand injection into the peritoneal cavity induced local eosinophil recruitment, indicating that TLR2 activation of other cell types can mediate eosinophil recruitment. After DSS treatment, mast cell-deficient (Kit(W-sh/W-sh)) mice had similar levels of intestinal tissue eosinophilia were observed as those in wild-type mice. However, mast cell-deficient mice were partially protected from DSS-induced weight loss, an effect that was reversed by mast cell reconstitution. Overall, this study indicates a critical role for indirect TLR2-dependent pathways, but not mast cells, in the generation of eosinophilia in the large intestine during experimental colitis and has important implications for the regulation of eosinophils at mucosal inflammatory sites.  相似文献   
145.
Microbiota composition and associated metabolic activities are essential for the education and development of a healthy immune system. Microbial dysbiosis, caused by risk factors such as diet, birth mode, or early infant antimicrobial therapy, is associated with the inception of allergic diseases. In turn, allergic diseases increase the risk for irrational use of antimicrobial therapy. Microbial therapies, such as probiotics, have been studied in the prevention and treatment of allergic diseases, but evidence remains limited due to studies with high heterogeneity, strain-dependent effectiveness, and variable outcome measures. In this review, we sketch the relation of microbiota with allergic diseases, the overuse and rationale for the use of antimicrobial agents in allergic diseases, and current knowledge concerning the use of bacterial products in allergic diseases. We urgently recommend 1) limiting antibiotic therapy in pregnancy and early childhood as a method contributing to the reduction of the allergy epidemic in children and 2) restricting antibiotic therapy in exacerbations and chronic treatment of allergic diseases, mainly concerning asthma and atopic dermatitis. Future research should be aimed at antibiotic stewardship implementation strategies and biomarker-guided therapy, discerning those patients that might benefit from antibiotic therapy.  相似文献   
146.
IntroductionImplantable cardioverter defibrillators register various types of arrhythmias. Thus they can be exploited to better identify patients with atrial fibrillation episodes and increase the proportion of patients who may benefit from implementation of pharmacological prophylaxis of thromboembolic events, most of which are asymptomatic. The aim of the study was to assess of the frequency, symptoms and predisposing factors for the occurrence of atrial fibrillation episodes in patients with an implanted implantable cardioverter defibrillator (ICD) and cardiac resynchronisation therapy with defibrillator (CRT-D) based on the analysis of intracardiac electrocardiograms (EGM/IEGM) records.Material and methodsThe study included 174 consecutive outpatients with heart failure, sinus rhythm and an implanted cardioverter defibrillator and cardiac resynchronisation therapy with defibrillator. Follow-up visits with analysis of IEGM records occurred every 3 months. During a mean follow-up of 20 months, 901 visits were carried out. One hundred forty-seven patients had at least 1 year of follow-up.ResultsAtrial fibrillation episodes in the study group occurred in 54 (31.0%) patients and 71.4% were asymptomatic. Predisposing factors were: history of paroxysmal atrial fibrillation (37.0% vs. 13.3%, p < 0.001), atrioventricular conduction abnormalities (42.6% vs. 20.0%, p = 0.002), intraventricular conduction abnormalities (59.3% vs. 40.8%, p = 0.02) and more severe mitral regurgitation (7.4% vs. 0.8%, p = 0.04). Chronic renal disease was a risk factor for death in the study group. No stroke occurred during the study.ConclusionsEpisodes of paroxysmal atrial fibrillation in patients with systolic heart failure and implanted cardioverter-defibrillator systems are quite common. The majority of the episodes recorded in the study were asymptomatic.  相似文献   
147.
IntroductionHybrid comprehensive telerehabilitation (HCTR) consisting of telecare (with psychological telesupport), telerehabilitation and remote monitoring of implantable devices might be an innovative option improving heart failure (HF) patients’ quality of life (QoL) and emotional health. The aim of the study was to investigate the influence of HCTR on various facets of QoL in HF patients in comparison with usual care (UC) alone.Material and methodsThe present analysis formed part of a multicenter, randomized trial that enrolled 850 HF patients (NYHA I–III, LVEF ≤ 40%). Patients were randomized 1 : 1 to HCTR plus UC or UC only. Patients underwent either an HCTR program or UC with observation. The psychological intervention in the HCTR group included supportive psychological counseling via mobile phone. The Medical Outcome Survey Short Form 36 Questionnaire was used to assess QoL. Measurements were made before and after a 9-week intervention (HCTR group)/observation (UC group).ResultsAfter the intervention, the HCTR group showed significant improvement in overall QoL, physical domain (PD) of QoL, and 4 areas of QoL (physical functioning (PhF), role functioning related to physical state (RF), general health (GH), vitality (VI)). A significant positive change in QoL in the UC group was observed only in VI and social functioning. There were also significant differences in QoL after 9-week intervention/observation between the two groups. The results showed greater improvement in HCTR for overall QoL (p = 0.009), PD of QoL (p = 0.0003) and three specific areas of QoL: PhF (p = 0.001), RF (p = 0.003), bodily pain (BP) (p = 0.015).ConclusionsIn comparison to UC, HCTR resulted in improvement in overall QoL, PD of QoL and 3 specific areas of QoL: PhF, RF and BP.  相似文献   
148.
149.

Objective

To describe the anatomy of pelvic autonomic nerves as it applies to nerve-sparing radical hysterectomy, and the technique, feasibility, and results of robotic nerve-sparing radical hysterectomy.

Methods

Prospective evaluation of 6 patients undergoing robotic nerve-sparing radical hysterectomy (type C1) for cervical cancer Stage IB (1B1 in 3 and 1B2 in 3 patients). Pelvic lymphadenectomy was performed in 3 patients and pelvic and aortic in the remaining 3 patients.

Results

The operation was completed in all patients. The mean age of the patients was 51.0 (range 33-73) and mean BMI 27.8 (range 23.2-35.1). The mean operating time was 238.6 min (range 207-256), mean blood loss 135 ml (range 100-150), mean number of lymph nodes was 23.6 (range 19-29), mean hospital stay was 2 days (range 1-4). There were no intraoperative complications. Postoperative complications occurred in 1 patient with an ileus who required an extended hospital stay. One patient did not regain normal urinary voidings until the fourth week after surgery. All patients remain free of disease.

Conclusion

Robotic nerve-sparing radical hysterectomy is safe and feasible. Urinary dysfunction may occur.  相似文献   
150.
Prognostic value of 5-microRNA based signature in T2-T3N0 colon cancer   总被引:1,自引:0,他引:1  
The role of adjuvant chemotherapy in stage T2-T3N0 colon cancer (CC) is controversial and there are currently no reliable factors allowing for individual selection of patients with high risk of relapse for such therapy. We searched for microRNA-based signature with prognostic significance in this group. We assessed by qRT-PCR expression of 754 microRNAs (miRNAs) in tumour samples from 85 stage pT2-3N0 CC patients treated with surgery alone. MiRNA expression was compared between two groups of patients: 40 and 45 patients who did and did not develop distant metastases after resection, respectively. Additionally, miRNA expression was compared between CC and normal colon mucosa samples and between the mismatch repair (MMR) competent and deficient tumours. Low expression of miR-1300 and miR-939 was significantly correlated with shorter distant metastasis-free survival (DMFS) in Cox univariate analysis (p.adjusted = 0.049). The expression signature of five miRNAs (miR-1296, miR-135b, miR-539, miR-572 and miR-185) was found to be prognostic [p = 1.28E?07, HR 8.4 (95 % CI: 3.81–18.52)] for DMFS and cross-validated in a leave-one-out analysis, with the sensitivity and specificity of 74 and 78 %, respectively. The expression of miR-592 was significantly associated with the MMR status (p.adjusted <0.01). The expression of several novel miRNAs were found to be tumour specific, e.g. miR-888, miR-523, miR-18b, miR-302a, miR-423-5p, miR-582-3p (p < 0.05). We developed a miRNA expression signature that may be predictive for the risk of distant relapse in early stage CC and confirmed previously reported association between miR-592 expression and MMR status.  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