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   318992篇
  免费   31647篇
  国内免费   23296篇
耳鼻咽喉   2713篇
儿科学   3465篇
妇产科学   3696篇
基础医学   38420篇
口腔科学   5564篇
临床医学   44376篇
内科学   43784篇
皮肤病学   3708篇
神经病学   16792篇
特种医学   12303篇
外国民族医学   212篇
外科学   29956篇
综合类   56162篇
现状与发展   90篇
一般理论   31篇
预防医学   21019篇
眼科学   9372篇
药学   35353篇
  361篇
中国医学   19984篇
肿瘤学   26574篇
  2024年   365篇
  2023年   4602篇
  2022年   7582篇
  2021年   14627篇
  2020年   12804篇
  2019年   11007篇
  2018年   11499篇
  2017年   10559篇
  2016年   9997篇
  2015年   15234篇
  2014年   18943篇
  2013年   16840篇
  2012年   24882篇
  2011年   27850篇
  2010年   17859篇
  2009年   14138篇
  2008年   17895篇
  2007年   17595篇
  2006年   17634篇
  2005年   17134篇
  2004年   10623篇
  2003年   9680篇
  2002年   8118篇
  2001年   6796篇
  2000年   7263篇
  1999年   7767篇
  1998年   4944篇
  1997年   5006篇
  1996年   3821篇
  1995年   3727篇
  1994年   3083篇
  1993年   2062篇
  1992年   2336篇
  1991年   1954篇
  1990年   1646篇
  1989年   1382篇
  1988年   1184篇
  1987年   992篇
  1986年   767篇
  1985年   627篇
  1984年   369篇
  1983年   225篇
  1982年   123篇
  1981年   133篇
  1980年   90篇
  1979年   100篇
  1974年   7篇
  1972年   8篇
  1939年   6篇
  1937年   5篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
81.
目的 探讨原发性高血压患者红细胞分布宽度(RDW)与血浆肾素活性、肱踝动脉脉搏波传导速度(baPWV)、颈动脉斑块的相关性.方法 连续入选河南省人民医院2016年1月至2019年11月确诊的原发性高血压患者531例.采用全自动血液细胞检测仪,测定RDW.根据RDW四分位数将患者分为四组,比较四组血浆肾素活性、baPWV、颈动脉斑块发生率的差异.结果 RDW 1~4四分位组立位肾素活性分别为0.6(0.3~1.6)、0.9(0.4~2.2)、1.4(0.3~2.7)、1.8(0.4~4.3)μg/(L·h);左侧baPWV分别为1476(1334~1682)、1498(1354~1703)、1568(1436~1754)、1612(1447~1834) cm/s,右侧baPWV分别为1514(1337~1694)、1504(1367~1727)、1576(1444~1802)、1612(1450~1843) cm/s;颈动脉斑块发生率分别为32.6%、43.8%、48.5%、54.0%;4组间比较,差异有统计学意义(均P<0.01).相关性分析显示,RDW与立位肾素活性、baPWV(右侧)和baPWV(左侧)呈正相关(相关系数分别为0.229、0.224和0.243,均P<0.01).颈动脉有斑块组RDW显著高于颈动脉无斑块组(P=0.001).采用偏相关分析校正24 h收缩压后,结果显示颈动脉斑块、立位肾素活性、右侧baPWV和左侧baPWV与RDW呈正相关,相关系数分别为0.095、0.194、0.158和0.152(均P<0.01).结论 原发性高血压患者RDW与立位肾素活性、baPWV及颈动脉斑块呈正相关.  相似文献   
82.
目的 探讨经颅直流电刺激(tDCS)对精神分裂症伴迟发性运动障碍(TD)患者空间工作记 忆的影响。方法 选取2017 年6 月至2018 年1 月来源于苏州市广济医院、苏州市社会福利总院、太仓市 精神卫生中心、南充市第六人民医院四家精神专科医院的38 例住院精神分裂症伴TD 患者,随机分为试 验组(21 例)和对照组(17 例)。研究期间,两组患者均接受常规药物治疗,试验组予以tDCS 治疗,采用的 电流为2 mA,刺激部位为左侧背外侧前额叶皮质及对侧眶上缘;对照组相应地予以伪tDCS 治疗。在基 线期、治疗15 次结束后及2 周后进行随访,采用剑桥神经心理自动化成套测试(CANTAB)中的空间工作 记忆(SWM)模块分别对两组患者进行认知测评。结果 在完成15 次治疗后,试验组SWM 指标分析中 的总错误数[31.00(28.50,49.00)]、平均第一次响应时间(4 盒子)[3 289.500(1 871.750,5 018.000)ms]、 平均第一次响应时间(6 盒子)[2 862.500(2 128.500,4 672.250)ms]、平均第一次响应时间(8 盒子) [3 328.500(2 611.250,5 120.750)ms]与对照组比较,差异无统计学意义(P> 0.05);试验组SWM 指标分 析中的策略分[19.00(17.00,20.00)]低于对照组[21.00(19.50,23.00)],差异有统计学意义(P < 0.05)。 在2 周后的随访中,两组的SWM 各指标比较,差异均无统计学意义(P> 0.05)。结论 tDCS 可能对精神 分裂症患者使用策略的能力有即刻改善效应。  相似文献   
83.
BackgroundLaparoscopic living donor right hepatectomy (LDRH) was a controversial topic due to its unknown safety and feasibility.MethodsPubMed, EMBASE and Cochrane Library databases were searched for studies comparing LDRH with open living donor right hepatectomy (ODRH), which were published between the date of database establishment and June 2020. Revman5.3 was used for statistical analysis.ResultsFourteen studies were included. For the donors, there was no significant difference in warm ischemic time, hospital stay, graft weight, hepatic arterial anomalies (HAA), hepatic vein anomalies (HVA), portal vein anomalies (PVA), biliary anomalies, bleeding, wound infection, severe complication rate and readmission rate. The estimated blood loss, incidence of complication, intra-abdominal fluid rate in the LDRH group were significantly lower than those in the ODRH group, while the operation time, time to remove liver in the LDRH group were significantly higher than those in the ODRH group. For the recipients, there was no significant difference in complication rate, bleeding, HAA, PVA, biliary anomalies, graft failure and mortality. The HVA rate in the LDRH group was significantly higher than that in the ODRH group.ConclusionLDRH is safe and feasible for adult living donor liver transplantation compared with ODRH and it can reduce intraoperative bleeding and postoperative complication in donors, which requires further verification by more multi-center comparative studies with large sample and high quality.  相似文献   
84.
目的 基于网络药理学进行前列消汤治疗慢性前列腺炎的预测,同时采用临床试验进行验证,证明前列消汤对ⅢA型前列腺炎患者的临床疗效及对前列腺液(Expressed Prostatic Secretion, EPS)中白细胞介素17(interleukin 17, IL-17)及双头叉转录因子p3(Forkhead box p3, Foxp3)表达的影响。方法 采用网络信息学分析方法,筛选出前列消汤在ⅢA型前列腺炎治疗中发挥疗效的主要作用靶点,采用临床随机非盲法,将符合纳入标准的80例ⅢA型前列腺炎湿热下注证患者随机分为观察组和对照组各40例,观察组口服自拟前列消汤,对照组口服银花泌炎灵片。观察治疗前后两组的症状及证候评分情况、前列腺按摩液以及其IL17、Foxp3表达的差异。取40例正常男性前列腺液为正常对照。结果 网络药理学分析结果提示IL17信号通路为前列消汤治疗慢性前列腺炎的重要通路之一,临床试验结果提示经治疗后观察组有效率达89.19%,较对照组的73.68%为优(P < 0.05)。两组患者服药后的临床表现、前列腺按摩液WBC、症状及证候评分均存在明显改善。观察组和对照组IL-17水平较治疗前下降,Foxp3表达较治疗前升高(P < 0.05)。观察组对降低IL-17表达和提升Foxp3表达上较对照组差异更大(P < 0.05)。观察组治疗后与正常组IL-17和Foxp3水平比较差异较小(P > 0.05)。结论 网络药理学能一定程度上预测中药作用于疾病的相应靶点,前列消汤对ⅢA型前列腺炎湿热下注证患者的临床症状有明显改善作用,并能降低IL-17表达,对Foxp3表达有提升作用,在总有效率和对细胞因子的影响上较银花泌炎灵片组明显。  相似文献   
85.
【摘要】 目的 明确1个LEOPARD综合征家系的PTPN11基因突变。方法 对中国科学院大学宁波华美医院确诊的1例LEOPARD综合征先证者的家系进行现场调查。提取家系内4例患者、2例健康成员及与该家系无关的100例健康对照外周血标本。PCR扩增PTPN11基因所有外显子,使用Sanger测序法进行突变位点分析。结果 该家系3代14人,其中6人患病(男3例,女3例),符合常染色体显性遗传。患者皮损主要分布于面部、躯干和四肢,具有特殊面容及心血管系统异常。4例患者存在PTPN11基因的错义突变c.1632G>T(p.R558L),导致第558位由精氨酸变为亮氨酸,该突变既往未曾报道。该家系2例健康成员及100例健康对照未发现PTPN11基因突变。结论 该LEOPARD综合征家系患者PTPN11基因13号外显子发生c.1632G>T错义突变,可能是该家系患者发病的分子基础。  相似文献   
86.
小细胞肺癌(small cell lung cancer,SCLC)是一种恶性程度高,具有高度侵袭性神经内分泌功能的肿瘤[1-2]。SCLC病情进展快,预后效果较差,研究报道局限期SCLC治愈机率为20%~25%,而广泛期SCLC采用的治疗以放化疗为主[3-4]。由于SCLC发病时具有隐匿特点,早期诊断与鉴别诊断难度较高。但随着临床病理研究的深入,影像学技术水平不断成熟,采用低剂量CT进行肺癌筛查可提高肺癌的早期检出率,并且联合手术、CT引导下穿刺活检、气管镜以及胸水细胞学等辅助检查可进一步增强早期SCLC诊断准确率,临床中尽早了解SCLC CT影像学特征与组织病理特征对于治疗具有临床价值。  相似文献   
87.
Background:We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy.Methods:We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models.Results:Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS.Conclusion:Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.  相似文献   
88.
Near-infrared diffuse correlation spectroscopy/tomography (DCS/DCT) has recently emerged as a noninvasive measurement/imaging technology for tissue blood flow. In DCT studies, the high-dense collection of light temporal autocorrelation curves (g2(τ)) via fiber array are critical for image reconstruction of blood flow. Previously, the camera-based fiber array limits the field of view (FOV), precluding its applications on large-size human tissues. The line-shape fiber probe based on lens combination, which is predominantly used in current DCT studies, requires rotated-scanning over the surface of target tissue, substantially prolonging the measurement time and increasing the system instability. In this study, we design a noncontact optical probe for DCT based on collimating micro-lens fiber array, termed as FA-nc-DCT system. For each source/detector fiber, a single optical path was collimated by coupling with one micro-lens in the fiber array that is integrated in a square-shape base. Additionally, an 8×8 optical switch is used to share the hardware laser and detectors without spatial scanning. The FA-nc approach for the precise collection of g2(τ) curves was validated through a speed-varied phantom experiment and the human experiments of cuff occlusion, from which the expected value of the blood flow index (BFI) was obtained. Furthermore, the flow anomaly in the phantom and the ischemic muscle in human were accurately reconstructed from the FA-nc-DCT system, which is combined with the imaging framework based on the Nth-order linear algorithm that we recently created. Those outcomes demonstrated the great potential of FA-nc-DCT technology for fast and robust imaging of various diseases such as human breast cancers.  相似文献   
89.
Lessons Learned
  • The overall safety profiles of ipilimumab 3 mg/kg and 10 mg/kg administered every 3 weeks, were consistent between Chinese patients with solid tumors in the current study and patients from previous U.S. ipilimumab monotherapy studies. No new safety signals were identified.
  • The mean systemic exposures to ipilimumab (assessed by first dose area under the curve during the dosing interval and maximum serum concentration) were numerically lower in the Chinese patient population than in U.S. patients for both 3 mg/kg and 10 mg/kg doses; however, the range of serum concentrations in the Chinese and U.S. populations overlapped (3 mg/kg and 10 mg/kg), suggesting that ipilimumab pharmacokinetics was ethnically insensitive in this study.
BackgroundThis phase I, open‐label study assessed ipilimumab safety, tolerability, pharmacokinetics (PK), immunogenicity, and antitumor activity in Chinese patients with unresectable, metastatic, recurrent malignant melanoma (MM) or nasopharyngeal carcinoma (NPC).MethodsOf 39 patients enrolled, 25 received ipilimumab (11 patients received 3 mg/kg, and 14 patients received 10 mg/kg). Reasons for not receiving treatment were withdrawal of consent (3 patients), no longer meeting the criteria (10 patients), and one recorded as “other.” During the induction phase, patients received ipilimumab (3 mg/kg, i.v.), on day 1 of a 3‐week cycle, to a maximum of four doses or progressive disease (PD). During the maintenance phase at week 24, patients received ipilimumab (3 mg/kg, i.v.) on day 1 of a 12‐week cycle, to a maximum of 3 years or PD. Considering the co‐primary safety and PK endpoints, the successive dosing required nine patients with two or fewer dose‐limiting toxicities during the 42‐day observation period to proceed with a new cohort of nine patients at 10 mg/kg.ResultsIpilimumab safety and PK profiles were similar in Chinese and predominantly White populations. Ipilimumab was well tolerated. Most adverse events (AEs) were grades 1–2 and experienced by 11 patients treated with 3 mg/kg and 14 patients treated with 10 mg/kg. There were no new safety concerns. Incidence of anti‐ipilimumab antibodies was low (1 of 10 in the 3 mg/kg patients and 2 of 13 in the 10 mg/kg patients) and without safety implications. In the 3 mg/kg group, 8 of 11 patients had PD. In the 10 mg/kg group (all NPC, 0 MM patients), 11 of 14 patients had PD. Three patients had stable disease (one at 3 mg/kg and two at 10 mg/kg).ConclusionIpilimumab was well tolerated in Chinese patients, showing similar safety and PK to previous studies in predominantly White populations.  相似文献   
90.
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments.  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