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   25654篇
  免费   1972篇
  国内免费   949篇
耳鼻咽喉   29篇
儿科学   582篇
妇产科学   182篇
基础医学   1737篇
口腔科学   41篇
临床医学   2761篇
内科学   7228篇
皮肤病学   52篇
神经病学   650篇
特种医学   2388篇
外国民族医学   13篇
外科学   3205篇
综合类   4254篇
现状与发展   3篇
预防医学   610篇
眼科学   82篇
药学   2301篇
  11篇
中国医学   1013篇
肿瘤学   1433篇
  2024年   18篇
  2023年   419篇
  2022年   563篇
  2021年   899篇
  2020年   912篇
  2019年   924篇
  2018年   908篇
  2017年   937篇
  2016年   896篇
  2015年   993篇
  2014年   1594篇
  2013年   1783篇
  2012年   1385篇
  2011年   1509篇
  2010年   1220篇
  2009年   1369篇
  2008年   1254篇
  2007年   1383篇
  2006年   1219篇
  2005年   1028篇
  2004年   806篇
  2003年   787篇
  2002年   641篇
  2001年   577篇
  2000年   479篇
  1999年   376篇
  1998年   367篇
  1997年   329篇
  1996年   331篇
  1995年   314篇
  1994年   323篇
  1993年   232篇
  1992年   213篇
  1991年   213篇
  1990年   151篇
  1989年   148篇
  1988年   125篇
  1987年   104篇
  1986年   101篇
  1985年   128篇
  1984年   102篇
  1983年   54篇
  1982年   83篇
  1981年   67篇
  1980年   73篇
  1979年   55篇
  1978年   41篇
  1977年   44篇
  1976年   28篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Optimal treatment of patients with various types of liver tumors or certain liver diseases frequently demands major liver resection, which remains a clinical challenge especially in children.Eighty seven consecutive pediatric liver resections including 51 (59%) major resections (resection of 3 or more hepatic segments) and 36 (41%) minor resections (resection of 1 or 2 segments) were analyzed. All patients were treated between January 2010 and March 2018. Perioperative outcomes were compared between major and minor hepatic resections.The male to female ratio was 1.72:1. The median age at operation was 20 months (range, 0.33–150 months). There was no significant difference in demographics including age, weight, ASA class, and underlying pathology. The surgical management included functional assessment of the future liver remnant, critical perioperative management, enhanced understanding of hepatic segmental anatomy, and bleeding control, as well as refined surgical techniques. The median estimated blood loss was 40 ml in the minor liver resection group, and 90 ml in major liver resection group (P < .001). Children undergoing major liver resection had a significantly longer median operative time (80 vs 140 minutes), anesthesia time (140 vs 205 minutes), as well as higher median intraoperative total fluid input (255 vs 450 ml) (P < .001 for all). Fourteen (16.1%) patients had postoperative complications. By Clavien-Dindo classification, there were 8 grade I, 4 grade II, and 2 grade III-a complications. There were no significant differences in complication rates between groups (P = .902). Time to clear liquid diet (P = .381) and general diet (P = .473) was not significantly different. There was no difference in hospital length of stay (7 vs 7 days, P = .450). There were no 90-day readmissions or mortalities.Major liver resection in children is not associated with an increased incidence of postoperative complications or prolonged postoperative hospital stay compared to minor liver resection. Techniques employed in this study offered good perioperative outcomes for children undergoing major liver resections.  相似文献   
22.
Well-differentiated hepatocellular mass-lesions in non-cirrhotic livers have a differential diagnosis of focal nodular hyperplasia, regenerative hepatic pseudotumors, hepatic adenoma, hepatocellular carcinoma, and fibrolamellar carcinoma. Despite significant advances in characterizing these pseudotumors and tumors, they remain a diagnostic challenge, especially on needle biopsy. This review focuses on a systematic diagnostic approach, one that allows confident diagnosis of these lesions.  相似文献   
23.
24.
PurposeTo assess the critical role of transjugular intrahepatic portosystemic shunt (TIPS) in the management of Budd-Chiari syndrome (BCS), as the data with respect to the safety and outcome of TIPS in patients with BCS are scarce because of the rarity of the disease.Materials and MethodsA comprehensive search of literature of various databases from 2000 to October 2021 was conducted for studies evaluating the outcome of TIPS in patients with BCS. The primary outcomes of the analysis were technical and clinical success, adverse events and mortality associated with TIPS, dysfunction of TIPS, need for TIPS revision, need for liver transplantation (LT), and 1-year survival.ResultsA total of 33 studies (1,395 patients) were included in this meta-analysis. The pooled rates and 95% confidence intervals of various outcomes were 98.6% (97.6–99.7) for technical success, 90.3% (86.0–94.6) for clinical success, 10.0% (6.5–13.6) for major adverse events, 0.5% (0.2–1.0) for TIPS-related mortality, 11.6% (7.8–15.4) for post-TIPS hepatic encephalopathy (HE), 40.1% (32.5–47.7) for TIPS dysfunction, 8.6% (4.9–12.4) for the need for TIPS revision, 4.5% (2.8–6.2) for the need for LT, and 94.6% (93.1–96.1) for 1-year survival. Publication bias was seen with all outcomes except for post-TIPS HE, TIPS dysfunction, and the need for LT.ConclusionsThe existing literature supports the feasibility, safety, and efficacy of TIPS in the treatment of BCS. Deciding the optimal timing of TIPS in BCS needs further studies.  相似文献   
25.
PurposeTo assess clinical outcomes and patency after transjugular intrahepatic portosystemic shunt (TIPS) reduction for overshunting adverse events.Materials and MethodsThis multicenter, retrospective observational study included 33 patients (male-to-female ratio, 20:13; mean age, 59 years; mean Model for End-Stage Liver Disease [MELD] score, 15) who underwent TIPS reduction between 2007 and 2020. Procedure indications included medically refractory hepatic encephalopathy (HE) (85%), post-TIPS hepatic insufficiency (HI) (12%), and heart failure (3%). The measured outcomes included improvement in HE (classified using the West Haven system) and HI, patency of reduced TIPS, and transplant-free survival (TFS).ResultsTIPS reductions were successfully performed using parallel stent (94%) or other (6%) techniques at a median of 120 days after TIPS creation (HE, median, 164 days; HI, median, 5 days). The portosystemic pressure gradient increased from a mean of 10 to 17 mm Hg (P < .001). The overall HE rate after TIPS reduction was 54%; HE was persistent, improved, and resolved in 21%, 32%, and 46% cases, respectively. In patients with HI, the MELD score increased from a mean of 22 before TIPS to 34 after TIPS (P = .061), but without improvement (0%) in HI after TIPS reduction (mean MELD score, 30; P = .266). Recurrent ascites occurred in 14% of the patients. The median shunt patency was 961 days (95% confidence interval, 476–1,447). The 30-day, 6-month, 1-year, and 3-year shunt patency rates were 92%, 81%, 74%, and 37%, respectively. The median TFS was not reached. The 30-day, 6-month, 1-year, and 3-year survival rates were 97%, 90%, 81%, and 60%, respectively.ConclusionsAlthough TIPS reduction may be an effective and durable approach to treat post-TIPS medically refractory HE, shunt reduction may not achieve meaningful benefit for HI.  相似文献   
26.
27.
ObjectivesThe reduction of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery using an oxygen delivery-guided perfusion strategy (oxygen delivery strategy) for cardiopulmonary bypass management compared with a fixed flow perfusion (conventional strategy) remains controversial. The purpose of this study was to determine whether a oxygen delivery strategy would reduce the incidence of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery.MethodsWe randomly enrolled 300 patients undergoing cardiopulmonary bypass surgery. Patients were randomly assigned to a oxygen delivery strategy (maintaining a oxygen delivery index value >300 mL/min/m2 through pump flow adjustments during cardiopulmonary bypass) or a conventional strategy (a target pump flow was determined on the basis of the body surface area). The primary end point was the development of acute kidney injury. Secondary end points were the red blood cell transfusion rate and number of red blood cell units, intubation time, postoperative length of stay in the intensive care unit and the hospital, predischarge estimated glomerular filtration rate, and hospital mortality.ResultsAcute kidney injury occurred in 20 patients (14.6%) receiving the oxygen delivery strategy and in 42 patients (30.4%) receiving the conventional strategy (relative risk, 0.48; 95% confidence interval, 0.30-0.77; P = .002). The secondary end points were not significantly different between strategies. In a prespecified subgroup analysis of patients who had nadir hematocrit less than 23% or body surface area less than 1.40 m2, the oxygen delivery strategy seemed to be superior to the conventional strategy and the existence of quantitative interactions was suggested.ConclusionsAn oxygen delivery strategy for cardiopulmonary bypass management was superior to a conventional strategy with respect to preventing the development of acute kidney injury.  相似文献   
28.
目的 观察药物涂层球囊(DCB)治疗膝下动脉硬化性狭窄或闭塞致严重下肢缺血(CLI)的效果。方法 回顾性分析96例膝下动脉硬化性狭窄或闭塞致CLI患者,其中50例接受DCB治疗(DCB组)、46例接受普通球囊治疗(对照组),比较2组治疗效果、安全性及预后。结果 96例球囊均到达病变部位并成功完成扩张,未植入补救性支架。组间术前及术后即刻踝肱指数(ABI)、Rutherford分级及Wagner分级差异均无统计学意义(P均>0.05);术后6、12个月DCB组ABI高于、Rutherford分级及Wagner分级均低于对照组(P均<0.05)。术后6、12个月,DCB组一期通畅率均高于、管腔丢失均少于对照组(P均<0.05),组间截肢率差异均无统计学意义(P均>0.05)。Kaplan-Meier分析结果显示,术后12个月,DCB组免于临床驱动的靶病变血运重建率(CD-TLR)为89.81%,高于对照组的67.39%(P=0.008 8)。结论 DCB治疗膝下动脉硬化性狭窄或闭塞致CLI效果较好。  相似文献   
29.
PurposeTo prospectively determine the rate of radial artery occlusion (RAO) in patients undergoing transradial access for intra-arterial interventions.Materials and MethodsSeventy-seven patients undergoing transradial access from August 2019 to March 2021 for 120 intra-arterial procedures (yttrium-90 mapping [n = 39] and radioembolization [n = 38], uterine artery embolization [n = 19], transarterial chemoembolization [n = 10], active bleed embolization [n = 8], angiomyolipoma embolization [n = 4], and other [n = 2]) were enrolled. The average patient age was 59 years ± 13.1 (range, 30–90 years), and 43 (55.8%) of the 77 patients were men. The patients underwent radial artery (RA) palpation, ultrasound evaluation, the Barbeau test, and the reverse Barbeau test prior to and following the intervention. Verapamil, nitroglycerin, and heparin were administered in a total of 114 (95%) of the 120 procedures prior to starting the procedure. The incidence of RAO and radial artery spasm (RAS) was calculated, and univariate logistic regression was performed to analyze the predictors of RAS.ResultsThe preprocedural RA diameter (3.0 mm ± 0.67) was not significantly different from the postprocedural RA diameter (3.0 mm ± 0.65, P = .904). The RAO rate was determined to be 0.8% (1/120), and this artery recanalized within 1 week. Due to the small number of occlusions, statistical analysis of predictors of RAO was not performed. The rate of RAS was 22.7% (27/119). None of the variables tested—including age, sex, RA diameter, initial versus repeat access, operator experience, and artery puncture technique—showed significant prediction for RAS. Patients were seen for follow-up after 111 (92.5%) of the 120 procedures.ConclusionsTransradial access resulted in a <1% rate of RAO.  相似文献   
30.
Treatment of hepatocellular carcinoma (HCC) in the caudate lobe is technically challenging. This retrospective study was designed to evaluate the clinical outcome of both superselective transcatheter arterial chemoembolization (TACE) and liver resection (LR) for HCC occurring exclusively in the caudate lobe. From January 2008 to September 2021, a total of 129 patients were diagnosed with HCC of the caudate lobe. The Cox proportional hazard model was used to analyze the potential clinical factors and established prognostic nomograms with interval validation. Of the total number of patients, 78 received TACE and 51 received LR. The overall survival (OS) rates (TACE vs. LR) at 1, 2, 3, 4, and 5 years were 83.9% vs. 71.0%; 74.2% vs. 61.3%; 58.1% vs. 48.4%; 45.2% vs. 45.2%; and 32.3% vs. 25.0%, respectively. However, subgroup analysis revealed that TACE was superior to LR for treating patients with stage IIb Chinese liver cancer (CNLC-IIb) in the entire cohort (p = 0.002). Interestingly, no difference was found between TACE and LR in the treatment outcomes of CNLC-IIa HCC (p = 0.6). Based on Child-Pugh A and B calculations, TACE tended to lead to a better OS than LR (p = 0.081 and 0.16, respectively). Multivariate analysis showed that Child-Pugh score, CNLC stage, ascites, alpha fetoprotein (AFP), tumor size, and anti-HCV are related to OS. Predictive nomograms for 1, 2, and 3 years were performed. Based on this study, TACE may provide a longer OS than liver resection for patients with CNLC-IIb HCC of the caudate lobe. Because this suggestion is limited by the study design and relatively small sample size, additional randomized controlled trials are needed.  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