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   41226篇
  免费   2349篇
  国内免费   541篇
耳鼻咽喉   395篇
儿科学   715篇
妇产科学   213篇
基础医学   2049篇
口腔科学   1252篇
临床医学   4427篇
内科学   3437篇
皮肤病学   195篇
神经病学   1621篇
特种医学   8009篇
外国民族医学   14篇
外科学   3121篇
综合类   9042篇
一般理论   2篇
预防医学   3357篇
眼科学   261篇
药学   2607篇
  131篇
中国医学   776篇
肿瘤学   2492篇
  2024年   48篇
  2023年   495篇
  2022年   1070篇
  2021年   1705篇
  2020年   1734篇
  2019年   1320篇
  2018年   1395篇
  2017年   1547篇
  2016年   1595篇
  2015年   1323篇
  2014年   2980篇
  2013年   2544篇
  2012年   2330篇
  2011年   2725篇
  2010年   2291篇
  2009年   2361篇
  2008年   2124篇
  2007年   2131篇
  2006年   1776篇
  2005年   1480篇
  2004年   1125篇
  2003年   1102篇
  2002年   1044篇
  2001年   816篇
  2000年   711篇
  1999年   563篇
  1998年   479篇
  1997年   397篇
  1996年   339篇
  1995年   355篇
  1994年   332篇
  1993年   213篇
  1992年   198篇
  1991年   161篇
  1990年   134篇
  1989年   122篇
  1988年   100篇
  1987年   106篇
  1986年   94篇
  1985年   157篇
  1984年   132篇
  1983年   57篇
  1982年   111篇
  1981年   102篇
  1980年   70篇
  1979年   51篇
  1978年   34篇
  1977年   22篇
  1976年   6篇
  1973年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的 运用CT区分脾脏血管性病变与淋巴瘤。方法 回顾性分析20例经手术、穿刺病理学检查证实的脾脏病变的发病年龄、性别、脾脏指数、病变大小、数目、有无液化、钙化、强化幅度、强化方式等特征,并进行统计学分析。结果 20例脾脏病变中,11例血管性病变(6例海绵状血管瘤,3例窦岸细胞血管瘤,2例硬化性血管瘤样结节性转化),9例淋巴瘤;两组间发病年龄、病变大小、数目、有无液化、钙化等差异无统计学意义;两组间脾脏指数、动脉期强化幅度差异具有统计学意义(P<0.05)。5例海绵状血管瘤呈不均匀性强化,1例呈渐进性填充式强化,2例窦岸细胞血管瘤呈“雀斑征”,1例硬化性血管瘤样结节性转化呈“辐轮征”;9例淋巴瘤实质部分均呈均匀、轻中度强化。结论 脾脏血管性病变与淋巴瘤CT表现不同,CT有助于明确诊断。  相似文献   
3.
4.
Pulmonary thromboembolism (PTE) is an important cause of mortality/morbidity even today despite advancement in clinical understanding as well as diagnostic facilities. Clinical diagnosis of PTE is often challenging because of nonspecific sign/symptoms. Adherence to clinical decision-making protocols and appropriate use of diagnostic modalities like computed tomography pulmonary angiography can resolve the diagnostic dilemma in most cases and help in the overall management of PTE. This article deals with various concerns as well as controversies surrounding accurate diagnosis of PTE as on date.  相似文献   
5.
BackgroundLymph node recurrences (LNR) from colorectal cancer (CRC) still represent a therapeutic challenge, as standardized recommendations have yet to be established. The aim of this study was to analyze short- and long-term oncological outcomes following resection of LNR from CRC.MethodsAll patients with previously resected CRC who underwent histopathologically confirmed LNR resection in 3 tertiary referral centers between 2010 and 2017 were reviewed. Short- and long-term outcomes were analyzed, mainly recurrence-free and overall survival. Further recurrences following LNR resection were also analyzed.ResultsOverall, 18 patients were included. Primary CRC was left-sided in 16 (89%) patients, staged T3-4 in 15 (83%), N+ in 14 (78%) and presented with synchronous metastases in 8 (43%). Median time interval between primary CRC and LNR resections was 31 months. Performed lymphadenectomies were aortocaval (n = 10), pelvic (n = 7), in hepatic pedicle (n = 3) and mesenteric (n = 1). Four patients had associated liver metastases resection. Three (17%) presented with postoperative complications, of which one Clavien-Dindo 3. Fourteen (78%) patients presented with further recurrences after a mean delay of 9 months, with 36% of patients presenting with early (<6 months) recurrence. Five (36%) patients could undergo secondary recurrence resection and 3 (21%) patients radiotherapy. Median overall survival following LNR resection reached 44 months.ConclusionsCurrent results suggest that LNR resection is feasible and associated with improved survival, in selected patients. Longer time interval between primary CRC resection and LNR occurrence appeared to be a favorable prognostic factor whereas multisite recurrence appeared to be associated with impaired long-term survival.  相似文献   
6.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  相似文献   
7.
目的探讨CT与MRI在脑梗死后出血性转变(HT)中的诊断价值。方法对2011-01—2014-04我院收治的45例HT患者的临床资料进行回顾性分析,对CT与MRI的检查结果进行对比。结果45例患者中,脑内血肿34例(75.6%),脑梗死病灶内片状、斑点状或条状出血11例(24.4%)。其中大面积脑梗死继发出血24例(53.3%),中等面积继发出血15例(33.3%),小面积脑梗死继发出血6例(13.3%);CT检出HT 10例(22.2%),MRI检出45例(100%),差异有统计学意义(P0.05);在对不同部位的HT检查中,CT检出幕上出血9例(20.0%),幕下出血1例(2.2%);MRI检出幕上出血39例(86.7%),幕下出血6例(13.3%)。MRI对幕上及幕下出血的检出率均优于CT(P0.05)。结论在HT的诊断中,MRI比CT更加准确和敏感,在判断出血时间、指导临床治疗以及预后判断中具有重要意义。  相似文献   
8.
ObjectiveThe detection of abnormal findings on computed tomography (CT) scans of tuberculosis contacts combined with normal plain radiographs contributes to the early detection of tuberculosis. However, the benefit of the early detection of abnormalities for the prevention of active tuberculosis during follow-up requires evaluation.MethodWe conducted retrospective comparison of the existence of CT scans of tuberculosis contacts without findings of active tuberculosis on plain radiographs at a hospital in Japan. Results: Among 243 contacts without CT scans, five developed tuberculosis during follow-up. Among 229 contacts with CT scans, 24 were judged as targets of multi-drug therapy since their CT findings were suggestive of active tuberculosis at the time of the CT screening. Among 205 contacts judged as having latent tuberculous infection with CT screening, three developed tuberculosis diseases during follow-up. Conclusion: CT scans detected abnormal findings among contacts without abnormalities of plain radiographs but there were some contacts that developed tuberculosis diseases among those with contact investigation including CT scan. The value of CT is equivocal considering the balance of true treatment, overtreatment and harm of radiation.  相似文献   
9.
Objective: To observe the clinical effect of modified akupotomye closed lysis under CT guidance on compression of posterior lumbar nerve branch.Methods: Patients were diagnosed by HRCT 3-D reconstruction combined with clinical symptoms and signs.After HRCT three-dimensional reconstruction combined with clinical symptoms and signs, the patients were confirmed as posterior lumbar nerve compression.After CT accurate surface positioning, CT-guided modified akupotomye was used for closed lysis of the posterior lumbar nerve branch.Oswestry Dysfunction Index Questionnaire(ODI) was used for quantitative scoring, 7 days before and after treatment and 6 months after treatment.Results: In 62 cases, 20 cases were cured, with 25 cases markedly effective, 11 cases effective, and 36 cases ineffective.The total effective rate was 90.3%.ODI score: Self-paired t test 7 days before after treatment, P < 0.01;Before treatment and 6 months after treatment, self-paired t test(P < 0.01);Self-paired t-test was performed 7 days after treatment and 6 months after treatment(P > 0.05).Conclusion: With CT precise positioning, the modified akupotomye can be used to do closed lysis, to relieve the adhesion and compression, so that the low back pain can be relieved, with good clinical.The akupotomye closed lysis, combined with modern imaging technology has not only achieved good clinical effect, but also can improve the accuracy, safety and scientificity of akupotomye treatment.  相似文献   
10.
目的通过CT影像测量了解漏斗胸Nuss矫形术前后胸廓径线的改变情况,探讨并分析Nuss矫形术对胸廓的影响及相关因素。方法对2014年1月至2018年12月郑州大学第一附属医院收治的50例行漏斗胸Nuss矫形术患儿的临床资料进行回顾性分析。50例患儿中男43例,女7例。所有患儿中存在脊柱侧弯6例,胸廓不对称12例,胸骨旋转11例。通过CT影像测量其放置矫形器前及取出矫形器后胸廓各椎体平面最大横内径及该平面胸脊间的距离,通过配对样本t检验比较矫形前后各径线的改变情况,以及通过独立样本t检验分析在不同年龄、性别、矫形时间、漏斗胸对称与否、是否合并脊柱侧弯等情况间的差异性。结果50例患儿均顺利完成矫形器置入术及矫形器拔除术,无明显术中及术后并发症,Nuss矫形后较矫形前相比,胸廓前后径在第8~12胸椎水平均较前增加,第3~5胸椎平面较前减小,胸廓横径在第8~10胸椎平面较前减小;年龄≤10岁、矫形时长≥2年及女性患儿胸廓前后径改变量在多个胸椎平面分别较年龄>10岁、矫形时长<2年及男性患儿大,P<0.05,差异具有统计学意义。结论漏斗胸Nuss矫形后前胸壁凹陷较前明显改善,并且在不同年龄和不同矫形时长间存在差异性,年龄较小及适当增加矫形时间可获得较好的矫形效果,而胸廓横径生长在一定程度上受限。  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