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   11531篇
  免费   468篇
  国内免费   194篇
耳鼻咽喉   29篇
儿科学   476篇
妇产科学   324篇
基础医学   1295篇
口腔科学   206篇
临床医学   808篇
内科学   1465篇
皮肤病学   249篇
神经病学   1159篇
特种医学   175篇
外国民族医学   4篇
外科学   965篇
综合类   1460篇
预防医学   616篇
眼科学   155篇
药学   1411篇
  2篇
中国医学   389篇
肿瘤学   1005篇
  2023年   100篇
  2022年   218篇
  2021年   289篇
  2020年   180篇
  2019年   707篇
  2018年   581篇
  2017年   382篇
  2016年   252篇
  2015年   207篇
  2014年   460篇
  2013年   520篇
  2012年   548篇
  2011年   659篇
  2010年   554篇
  2009年   514篇
  2008年   514篇
  2007年   555篇
  2006年   374篇
  2005年   336篇
  2004年   266篇
  2003年   252篇
  2002年   236篇
  2001年   183篇
  2000年   140篇
  1999年   154篇
  1998年   99篇
  1997年   104篇
  1996年   98篇
  1995年   91篇
  1994年   88篇
  1993年   71篇
  1992年   59篇
  1991年   55篇
  1990年   47篇
  1989年   40篇
  1988年   30篇
  1987年   28篇
  1986年   35篇
  1985年   258篇
  1984年   422篇
  1983年   220篇
  1982年   252篇
  1981年   290篇
  1980年   189篇
  1979年   200篇
  1978年   123篇
  1977年   93篇
  1976年   49篇
  1975年   23篇
  1973年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
《Injury》2023,54(7):110767
AimThis network meta-analysis aims to compare functional outcomes and complications between conservative treatment and surgery for distal radius fractures in patients aged 60 years and over.MethodsWe searched the PubMed, EMBASE, and Web of Science databases for randomized controlled trials (RCTs) assessing the effect of conservative treatment and surgery for distal radius fractures in patients aged 60 years and over. Primary outcomes included grip strength and overall complications. Secondary outcomes included Disabilities of the Arm, Shoulder, and Hand (DASH) scores, Patient-Rated Wrist Evaluation (PRWE) scores, wrist range of motion and forearm rotation, and radiographic assessment. All continuous outcomes were assessed using standardized mean differences (SMDs) with 95% confidence intervals (CIs), and binary outcomes were assessed using odds ratio (OR) with 95% CIs. The surface under the cumulative ranking curve (SUCRA) was used to determine a hierarchy of treatments. Cluster analysis was performed for grouping treatments based on the SUCRA values of primary outcomes.ResultsFourteen RCTs were included to compare conservative treatment, volar lockedplate (VLP), K-wires fixation, and external-fixation. VLP outperformed conservative treatment for 1-year and minimum 2-year grip strength (SMD; 0.28 [0.07 to 0.48] and 0.27 [0.02 to 0.53], respectively). VLP yielded the optimal grip strength at 1-year and minimum 2-year follow-up (SUCRA; 89.8% and 86.7%, respectively). In a subgroup analysis of patients aged 60 to 80 years old, VLP outperformed conservative treatment in DASH and PRWE scores (SMD, 0.33 [0.10, 0.56] and 0.23 [0.01, 0.45], respectively). In addition, VLP had the fewest complications (SUCRA = 84.3%). Cluster analysis suggested that VLP and K-wire fixation were more effective treatment groups.ConclusionEvidence to date demonstrates that VLP provides measurable benefits in grip strength and fewer complications to those 60 years of age and over, and that benefit is not reflected in current practice guidelines. There is a subgroup of patients where K-wire fixation outcomes are similar to those of VLP; defining this subgroup may yield substantial societal benefits.  相似文献   
72.
目的探讨尿液核基质蛋白22(nuclear matrix protein 22,NMP22)、组织多肽特异性抗原(tissue polypeptide-specific antigen,TPS)、CYFRA21-1、糖链蛋白19-9(carbohydrate antigen 19-9,CA19-9)对肾盂尿路上皮癌的诊断价值.方法回顾性分析山西省肿瘤医院2010年1月至2015年12月检测的至少两种上述尿液肿瘤标志物的患者资料,共218人次,包括肾盂尿路上皮癌63例(A 组)、膀胱尿路上皮癌46例(B 组)、非尿路上皮肿瘤的泌尿系其他疾病62例(C 组)、A组行根治术后2年未复发47例(D 组),另有健康志愿者20例(E 组).比较各组尿 NMP22、TPS、CYFRA21-1、CA19-9表达水平,并绘制受试者工作特征(receiver operating characteristic,ROC)曲线,计算 ROC 曲线下面积.结果 A 组 NMP22水平高于 B 组,差异有统计学意义(P =0.001). A 组与 B 组的 TPS、CYFRA21-1、CA19-9水平差异无统计学意义(P >0.05).A 组和 B 组的 TPS、NMP22、CYFRA21-1、CA19-9水平均高于 C 组、D 组、E 组,差异有统计学意义(P <0?05).C 组、D组及 E 组的 NMP22、TPS、CYFRA21-1、CA19-9水平差异无统计学意义(P >0.05). A 组中NMP22、TPS、CYFRA21-1、CA19-9水平在不同病理分级、临床分期、肿瘤大小、是否肾积水等的差异无统计学意义(P >0.05).A 组 NMP22、TPS、CYFRA21-1、CA19-9的诊断准确率高于尿脱落细胞学检查,差异有统计学意义(P <0.05).四种肿瘤标志物的 ROC 曲线下面积为0.7~0.9,诊断效能中等,最高者为 NMP22与 CYFRA21-1的组合,为0.884.结论尿液 NMP22、TPS、CYFRA21-1、CA19-9对肾盂尿路上皮癌的诊断有帮助,诊断效能中等,但它们对肾盂癌肿瘤分期和病理分级的预测、术后监测、预后判断等方面的作用有待进一步研究.  相似文献   
73.
Oestrogen Receptor β (ERβ) gene plays an important role in the regulation of fertility in both males and females. Polymorphism in CA repeat located in the flanking region of ERβ has been shown to be associated with several diseases, but its association with male infertility has not been analysed so far. However, Rsa I polymorphism (rs1256049) in exon 5 of ERβ has been shown to be associated with male infertility in Caucasian patients. Hence, we have analysed 695 Indian men, including 443 infertile and 252 fertile men to evaluate the association of CA repeat length and Rsa I polymorphisms in male infertility. Our results revealed no significant difference in the distribution of CA repeat length between infertile (mean ± SD 23.24 ± 2.06, median 24) and fertile men (mean ± SD 23.16 ± 2.27, median 24). The analysis of dosage effect by classifying samples into SS (short/short), SL (short/long) and LL (long/long) groups also did not show any significant difference between infertile and fertile men. Similarly, Rsa I polymorphism also did not show any significant difference between infertile and fertile men. Furthermore, the combined analysis of CA repeat and Rsa I polymorphisms by haplotyping showed that the distribution of haplotypes was not significantly different between fertile and infertile men. Our results suggest that CA repeat length and Rsa I polymorphisms in ERβ are not associated with infertility in Indian men.  相似文献   
74.
Objectives. Carbonic anhydrase IX (CA IX) expression is induced by local hypoxia. We studied whether CA IX deposits associate with ascending aortic dilatation. Design. Aortic wall histology, CA IX expression, presence of leukocytes, plasma cells, macrophages, endothelial cells, smooth muscle cells, cell proliferation, elastin and collagen were studied in histological specimens collected from 30 patients who underwent surgery for ascending aorta. The samples were grouped according to presence of CA IX deposits. Results. Twenty out of 30 patients had CA IX-positive deposits within the adventitia, whereas 10 specimens remained negative. Adventitial inflammation was increased in CA IX-positive samples as compared with CA IX-negative ones (p?<?0.01). The mean diameter of the ascending aorta at the sinotubular junction increased significantly in patients with CA IX-positive staining as compared with CA IX-negative cases (63?±?3 vs 53?±?2?mm, p?<?0.02). Receiver operating characteristic curve analysis confirmed the association of CA IX positivity with increased ascending aortic dilatation (AUC 0.766; S.E. 0.090; p?=?0.020; 95% C.I. 0.590–0.941). Conclusions. Positive CA IX staining in certain aortic specimens suggests that increased CA activity may contribute to ascending aortic dilatation.  相似文献   
75.

Background

Obstructive jaundice is frequently associated with false CA19-9 elevation in benign conditions. The diagnostic accuracy of this tumor marker was evaluated in the present longitudinal study.

Methods

In 128 patients admitted for obstructive jaundice (87 with pancreato-biliary malignancy and 41 benign disease) serum CA19-9 was measured. Statistical analysis of marker levels obtained before and after endoscopic biliary drainage was performed in 60 patients.

Results

Elevated CA19-9 levels (>37 U/mL) were found in 61% of benign cases and 86% of malignancies. After biliary drainage, decrease of serum CA19-9 was observed in 19 of 38 malignant cases and in almost all benign cases (Wilcoxon matched pairs test: P = .207 and P <.001, respectively). Receiver operating characteristic (ROC) analysis identified a cut-off value of 90 U/mL to be associated with improved diagnostic accuracy after biliary drainage (sensitivity 61%, specificity 95%).

Conclusions

In the presence of successfully drained obstructive jaundice, CA19-9 serum levels that remain unchanged or measure more than 90 U/mL are strongly indicative of a malignant cause of obstruction. However, the real clinical utility of this marker remains controversial.  相似文献   
76.

Background

Arcuate ligament vascular compression syndrome has not been described previously in the pediatric or pediatric surgical literature. However, it is mentioned in the literature of vascular and general surgery and in journals of radiology and orthopedics. In this review, the intraoperative pathological anatomy and the principles of treatment for 8 children will be presented.

Methods

The chart records and the anatomical sketches that were documented by the surgeon immediately after each procedure were analyzed retrospectively. In addition, preoperative courses and long-term follow-up (range, 3-18 years) were evaluated by a defined program.

Results

The diagnosis of celiac artery compression by an arcuate ligament was suspected in children presenting with a history of several years of recurrent acute abdominal pain associated with a typical arterial bruit in the midline of the epigastric region.

Conclusions

Other diseases with recurrent abdominal pain and an arterial bruit must be excluded before making the decision for an operative intervention. Duplex ultrasound and angiography are possibly helpful tools to establish the respective diagnosis, but in the patients of the present series, these techniques neither confirmed compression of the celiac axis nor demonstrated decreased perfusion of the superior mesenteric artery. However, as the clinical symptoms clearly announce the disease, these diagnostic measures are not mandatory.  相似文献   
77.
Abstract

Purpose: To evaluate the effects of continuous magnetic field stimulation after four days of global encephalic ischemia on motor behavior and brain morphology in gerbils.

Material and methods: Sixty Mongolian gerbils were divided into five groups: Control (CG), sham (SG), ischemia (IG), ischemia north (INPG) and south (ISPG) pole. Experimental animals underwent bilateral occlusion of the carotid artery. In groups with magnetic stimulation, a 3200 gauss magnet was fixed to the skull. After brain perfusion, coronal sections of the striatum, motor cortex (M1) and CA1 area of the hippocampus (CA1) were cut and stained with hematoxylin and eosin.

Results: In the open field test (OF) we observed an increase in crossing in the IG compared to the CG, INPG and ISPG (F = 20.19), and a reduction in the time spent on the Rota-rod test (RR) with the IG compared to CG, IPNG and ISPG (F = 17.59). Morphometric analysis revealed a reduction in the density of the neurons in the CA1, in the number of M1 and striatal neurons in the IG compared to the CG, INPG and ISPG.

Conclusion: Our results demonstrate a potential therapeutic application of static magnetic fields for the preservation of motor behavior and neurons in regions analyzed after global cerebral ischemia.  相似文献   
78.
目的 了解武汉市及周边城市2011年4月至2012年3月手足口病的病原学及流行病学特征,为本地区手足口病的防治提供依据.方法 采集手足口病患者咽拭子标本,采用实时荧光定量PCR方法检测肠道病毒71型(EV71)和柯萨奇病毒A16型(CA16)的核酸.结果 2011年4月至2012年3月共收集手足口病咽拭子标本1844例,其中EV71阳性372例,阳性率为20.2%;CA16阳性460例,阳性率为24.9%;EV71和CA16双阳性38例,阳性率为2.1%.在病例收集期间,武汉及周边城市暴发的手足口病有2个高峰期,第1个高峰期为2011年5~7月春末夏初季节,EV71亚型为主要病原体;第2个高峰期为2011年9~12月秋末冬初季节,CA16病毒为主要病原体;发病患者集中于1~3岁儿童,且男性明显多于女性;散居儿童人数明显多于幼托儿童;EV71亚型患者发热、中枢神经系统(呕吐、肢颤、嗜睡和惊厥)症状所占比例要显著高于CA16亚型.结论 2011年武汉市及周边城市2个手足口病高峰期的主要病原体分别是由EV71和CA16亚型引起的,及早了解手足口病病原体的构成及流行病学特征,对于其防控具有重要意义.  相似文献   
79.
目的构建石墨烯-依来铬青蓝R(GO-ECR)免标记电化学免疫传感器高灵敏检测CA19-9的新技术。方法化学法合成氧化石墨烯并滴涂于电极表面,通过循环伏安法电沉积制作GO-ECR修饰玻碳电极,在偶联剂EDC和NHS作用下以共价键合方式将CA19-9抗体固定于修饰电极表面,固定的抗体与CA19-9发生免疫反应形成抗原-抗体复合物。铁氰化钾溶液作为检测探针,对比免疫反应前后铁氰化钾响应信号的差异,利用信号降低程度与CA19-9浓度正相关,实现对CA19-9的特异性高灵敏检测。结果该电化学免疫传感器检测CA19-9的线性范围为0.05~500 U/mL,检测限为0.01 U/mL,且能准确测定临床血清样本CA19-9的浓度。结论构建的GO-ECR免标记电化学免疫传感器可以简单、准确、特异地检测CA19-9。  相似文献   
80.
BackgroundSuper-obese patients can achieve adequate weight loss with long limb Roux-en-Y gastric bypass (RYGB). These patients, however, might need longer intestinal limbs to control co-morbidities such as type 2 diabetes, lipid disorders, hypertension, sleep apnea, and gastroesophageal reflux disorder.MethodsA total of 105 patients with a body mass index of ≥50 kg/m2 were randomly divided into 2 similar groups regarding sex, age, and number of co-morbidities. All underwent laparoscopic Roux-en-Y gastric bypass. In group 1, the length of the biliary limb was 50 cm and the length of the Roux limb was 150 cm. In group 2, the length of the biliary limb was 100 cm and the length of the Roux limb was 250 cm.ResultsThe follow-up for both group was 48 months. Diabetes was controlled in 58% of group 1 and in 93% of group 2 (P <0.05). Lipid disorders improved in 57% of group 1 and in 70% of group 2 (P <0.05). No statistical difference was found in the control or improvement of hypertension, sleep apnea, or gastroesophageal reflux disorder. The excess weight loss was faster in group 1 but was similar in both groups at 48 months (70% in group 1 and 74% in group 2), with no statistical difference.ConclusionPatients with longer biliary and Roux limbs achieved greater type 2 diabetes control, greater lipid disorder improvement, and showed a trend toward faster excess weight loss.  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