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   127857篇
  免费   7662篇
  国内免费   745篇
耳鼻咽喉   1239篇
儿科学   4004篇
妇产科学   2887篇
基础医学   18505篇
口腔科学   4936篇
临床医学   11632篇
内科学   28963篇
皮肤病学   3366篇
神经病学   12347篇
特种医学   3035篇
外国民族医学   1篇
外科学   11539篇
综合类   440篇
一般理论   56篇
预防医学   12590篇
眼科学   2133篇
药学   8955篇
中国医学   516篇
肿瘤学   9120篇
  2024年   149篇
  2023年   1246篇
  2022年   2729篇
  2021年   4545篇
  2020年   2823篇
  2019年   3827篇
  2018年   4356篇
  2017年   3223篇
  2016年   3785篇
  2015年   4143篇
  2014年   5492篇
  2013年   7081篇
  2012年   10866篇
  2011年   11228篇
  2010年   6065篇
  2009年   5114篇
  2008年   8770篇
  2007年   8749篇
  2006年   7997篇
  2005年   7434篇
  2004年   6664篇
  2003年   5928篇
  2002年   5316篇
  2001年   675篇
  2000年   499篇
  1999年   699篇
  1998年   888篇
  1997年   738篇
  1996年   618篇
  1995年   505篇
  1994年   467篇
  1993年   404篇
  1992年   340篇
  1991年   239篇
  1990年   228篇
  1989年   210篇
  1988年   207篇
  1987年   166篇
  1986年   182篇
  1985年   135篇
  1984年   171篇
  1983年   150篇
  1982年   167篇
  1981年   125篇
  1980年   127篇
  1979年   76篇
  1978年   87篇
  1977年   82篇
  1976年   61篇
  1974年   57篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
BackgroundTo analyze whether clinical and analytical parameters differ according to histopathology in cases of acute appendicitis (AA).MethodsThis is a retrospective, observational study including patients (>14 years of age) admitted for suspicion of AA from 1 April 2014 to 31 July 2016. Histopathology was divided into complicated (including perforated and gangrenous AA) and uncomplicated appendicitis (phlegmonous). Sex, age, temperature of patients on admission to the Emergency Department, symptom duration, preoperative white blood cell (WBC) count, neutrophil percentage, mean platelet volume (MPV), platelet distribution width (PDW), C-reactive protein (CRP) and hospital stay were compared in the two groups.ResultsThree hundred and thirty-five patients were analyzed, and 284 were included. Appendicitis was uncomplicated in 194 (68.3%) and complicated in 90 (31.7%). Age, symptom duration, neutrophil percentage, CRP and hospital stay were higher in the complicated AA group (P < .05). The mean differences between uncomplicated and complicated AA were: age 13.2 years (95% CI: 8.2-18.2), symptom duration 14.1 hours (95% CI: 6.3-21.9), neutrophil percentage 5.0% (95% CI: 3.2-6.8), CRP 73.6 mg/l (95% CI: 50.0-97.2) and hospital stay 2.2 days (95% CI: 1.4-3.0), with p<0.05 for all these variables. A model based on the preoperative parameters (age, symptom duration, neutrophil percentage and CRP) was calculated to predict the likelihood of complicated AA. The receiver operating characteristic (ROC) of the model had an area under the curve of 0.80 (95% CI 0.75-0.85).ConclusionThis model is able to diagnose complicated AA without the need for imaging techniques, although it must be validated with prospective analysis.  相似文献   
995.
Local excision (LE) has arisen as an alternative to total mesorectal excision for the treatment of early rectal cancer. Despite a decreased morbidity, there are still concerns about LE outcomes.This systematic-review and meta-analysis design is based on the “PICO” process, aiming to answer to three questions related to LE as primary treatment for early-rectal cancer, the optimal method for LE, and the potential role for completion treatment in high-risk histology tumors and outcomes of salvage surgery.The results revealed that reported overall survival (OS) and disease-specific survival (DSS) were 71%–91.7% and 80%–94% for LE, in contrast to 92.3%–94.3% and 94.4%–97% for radical surgery. Additional analysis of National Database studies revealed lower OS with LE (HR: 1.26; 95%CI, 1.09–1.45) and DSS (HR: 1.19; 95%CI, 1.01–1.41) after LE. Furthermore, patients receiving LE were significantly more prone develop local recurrence (RR: 3.44, 95%CI, 2.50–4.74). Analysis of available transanal surgical platforms was performed, finding no significant differences among them but reduced local recurrence compared to traditional transanal LE (OR:0.24;95%CI, 0.15–0.4). Finally, we found poor survival outcomes for patients undergoing salvage surgery, favoring completion treatment (chemoradiotherapy or surgery) when high-risk histology is present.In conclusion, LE could be considered adequate provided a full-thickness specimen can be achieved that the patient is informed about risk for potential requirement of completion treatment. Early-rectal cancer cases should be discussed in a multidisciplinary team, and patient's preferences must be considered in the decision-making process.  相似文献   
996.
BackgroundIntestinal adaptation has been extensively studied experimentally, but very limited data is available on human subjects. In this study we assessed intestinal adaption in humans with short bowel syndrome (SBS).MethodsWe comparatively evaluated mucosal hyperplasia, inflammation, barrier function and nutrient transport using histology, immunohistochemistry and qPCR for selected 52 key genes in duodenal biopsies obtained from children with SBS after weaning off parenteral nutrition (n = 33), and matched controls without intestinal pathology (n = 12). Small bowel dilatation was assessed from contrast small bowel series.ResultsDuodenal mucosa of SBS children showed increased histologic inflammation of lamina propria (p = 0.033) and mucosal mRNA expression of tumor necrosis factor (p = 0.027), transforming growth factor (TGF)-β2 (p = 0.006) and caveolin-1 (CAV1; p = 0.001). Villus height, crypt depth, enterocyte proliferation, apoptosis and expression of proliferation and nutrient transport genes remained unchanged. Pathologic small bowel dilatation reduced crypt depth (p = 0.045) and downregulated mRNA expression of interleukin (IL)-6 by three-fold (p = 0.008), while correlating negatively with IL6 (r = -0.609, p = 0.004). Loss of ileocecal valve (ICV) upregulated mRNA expression of toll-like receptor 4 (TLR4), TGF-β1, CAV1, several apoptosis regulating genes, and mRNA expression of zonulin (p < 0.05 for all).ConclusionsDespite successful adaptation to enteral autonomy, duodenal mucosa of SBS children displayed histologic and molecular signs of abnormal inflammation and regulation of epithelial permeability, whereas no structural or molecular signs of adaptive hyperplasia or enhanced nutrient transport were observed. Excessive dilatation of the remaining small bowel paralleled impaired duodenal crypt homeostasis, while absence of ICV modified regulation of mucosal inflammation, regeneration and permeability.Level of evidenceII  相似文献   
997.
Background/purposeAdolescents have poor outcomes following testicular torsion directly attributable to delay from onset of symptoms to presentation to hospital. The aim of this study was to investigate the barriers to urgent presentation in young men.MethodsSemistructured interviews were undertaken with young men (11–19 years), using a topic guide exploring issues surrounding testicular pain and health. Thematic analysis was undertaken using a framework approach.ResultsTwenty-seven adolescents were recruited, data saturation was reached at sixteen participants, and median age was 13.5 years (range 11–18). The process by which an adolescent gets to hospital with testicular pain is slow. They must recognize the problem and alert their parents, who then use a ‘watch and wait’ policy to assess need for medical review, often leaving it ‘a day’ or overnight. Adolescent males do not engage with healthcare services independently of their parents. Additional factors preventing early presentation include: absence of knowledge about testicular pathology from adolescents and their parents; concern from the young people about raising a false alarm and family concerns about burdening healthcare services.ConclusionsRecommendations include designing a testicular health education campaign for young men and educating parents regarding the medical conditions where a ‘watch and wait’ policy may be harmful to their child.Level of evidenceVI  相似文献   
998.
AimThe aim of this study is to present our experience in the management of hormonally active adrenal tumors in children.Material and methodsWe did a retrospective chart review of all children with hormonally active adrenal tumors evaluated at the endocrinology clinic and operated at our institution between 1983 and 2019.ResultsThere were 75 patients included in the study, 58 with adrenocortical tumors (ACTs) and 17 with pheochromocytomas (PCCs). Within the group of patients with ACTs, there were 41 females and 17 males. The mean age was 58.3 (SD: 87.9; range: 9–211) months. The clinical manifestation of the tumor's hormonal activity was virilization in 37 cases, Cushing syndrome in 5, and mixed in 16. A positive family history was present in 11 patients (18.9%). The mean tumor size was 48.2 (SD: 22.4; range: 7–120) mm. The pathological diagnosis was adenoma in 42 cases, carcinoma in 15 cases, and macronodular hyperplasia in 1. Median follow-up was 192 (range: 50–290) months. Tumor recurrence occurred in 6 patients (10.3%), and there were three disease-related deaths (5%). Within the group of patients with PCCs, there were 11 males and 6 females. The mean age was 146.7 (SD: 71.2; range: 60–216) months. A positive family history was present in 7 patients (41.2%). The mean tumor size was 36.6 (SD: 16.7; range: 7–120) mm. The pheochromocytoma was classified as benign in 15 cases and as malignant in 2. During a median follow-up of 180 (range: 127–300) months, recurrence was observed in 6 cases (35.3%) and disease-related death in 1 case (5.9%).ConclusionsProper diagnosis and management at our referral center were associated with a high cure rate, even in cases of malignant tumors. Familial surveillance is highly recommended.Level of evidenceLevel IV.  相似文献   
999.
IntroductionA fast and cheap method of skin assessment in systemic sclerosis (SSc) is an area of extensive research. Established in 1979, the Rodnan skin score is a palpation-based method used among clinicians. This method has some limitations, such as: examiner’s skills, subjective results, and no standardization. In the last few years researchers have been exploring ultrasound-based techniques as a possible tool for skin assessment among patients with SSc. The aim of the study is to develop a protocol of elastography-based skin imaging evaluation among patients with SSc.Material and methodsReview of the literature and own experience.ResultsProposition of elastography-based skin imaging protocol among patients with SSc.ConclusionsThe authors present a potential protocol of ultrasound-based examination of skin involvement among patients with SSc.  相似文献   
1000.
IntroductionSystemic sclerosis/scleroderma (SSc) is a chronic autoimmune disease with connective tissue, multi-organ, and multisystem involvement. The disease has three main characteristics, namely vasculopathy, fibrosis, and autoimmunity. The effect of high-intensity interval training (HIIT) in aerobic exercise on other rheumatic diseases has been studied, for example in patients with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). The purpose of this work is to investigate the effectiveness of HIIT of aerobics exercise on improving the inspiratory muscle, quality of life and functional ability for systemic sclerosis subjects.Material and methodsThe study was conducted on patients with confirmed systemic sclerosis who met the inclusion criteria. The research was carried out for 12 months in the outpatient clinic and gait laboratory of the Department of Physical Medicine and Rehabilitation.ResultsAfter HIIT in aerobic exercise, we found significant changes in inspiratory muscle (SNIP values 45.67 [30.92] vs. 54.25 [22.71]), handgrip (13.14 [4.42] vs. 15.63 [4.08]), walking speed (184.70 [26.86] vs. 246.6 [12.30]), metabolic equivalent (3.53 [0.30] vs. 4.21 [1.25]) and Scleroderma-Specific Health Assessment Questionnaire Disability Index for all visual analog scale (VAS) domains except Disability Index. Exercise approaches are characterized by repeated cycles of exercise interrupted by rest. For a range of clinical conditions, HIIT in aerobic exercise is known to remedy blood vessel function.ConclusionsOur results suggest that HIIT in aerobic exercise has improved functional ability, respiratory muscle strength, and quality of life in SSc subjects. Training twice a week in a 12-week HIIT program is considered to be safe for this population. We have to consider internal and external factors that influenced the result. A larger sample and further exploration of the feasibility of combined exercise in SSc patients should be the focus for future research.  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