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   16756篇
  免费   1037篇
  国内免费   363篇
耳鼻咽喉   188篇
儿科学   363篇
妇产科学   324篇
基础医学   1491篇
口腔科学   320篇
临床医学   1437篇
内科学   1211篇
皮肤病学   420篇
神经病学   229篇
特种医学   644篇
外国民族医学   4篇
外科学   5786篇
综合类   2607篇
预防医学   446篇
眼科学   98篇
药学   964篇
  8篇
中国医学   538篇
肿瘤学   1078篇
  2024年   12篇
  2023年   174篇
  2022年   221篇
  2021年   461篇
  2020年   471篇
  2019年   406篇
  2018年   452篇
  2017年   520篇
  2016年   482篇
  2015年   485篇
  2014年   1021篇
  2013年   904篇
  2012年   869篇
  2011年   1122篇
  2010年   968篇
  2009年   853篇
  2008年   914篇
  2007年   1011篇
  2006年   921篇
  2005年   829篇
  2004年   694篇
  2003年   587篇
  2002年   537篇
  2001年   467篇
  2000年   342篇
  1999年   278篇
  1998年   279篇
  1997年   248篇
  1996年   176篇
  1995年   160篇
  1994年   140篇
  1993年   126篇
  1992年   120篇
  1991年   102篇
  1990年   71篇
  1989年   87篇
  1988年   81篇
  1987年   69篇
  1986年   62篇
  1985年   76篇
  1984年   55篇
  1983年   48篇
  1982年   61篇
  1981年   62篇
  1980年   42篇
  1979年   16篇
  1978年   13篇
  1977年   19篇
  1976年   18篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
胆囊切除术是公认的胆囊良性疾病的治愈手段,国内外学术界对于手术适应证和手术时机已有明确共识。近年来,“保胆手术”治疗胆囊良性疾病颇受热议,一些医生将“保护胆囊”的学术观点等同于“保留胆囊”的手术技术,这种误解可能导致病人出现差异性的预后。因此,临床医师应明晰“保护胆囊”理念与“保胆手术”的差别,对胆囊良性疾病的诊疗原则有正确的理解和应用。  相似文献   
2.
PurposeTo review and to compare indirectly the outcomes of minimally invasive therapies for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia.Materials and MethodsA literature search via Medline and Cochrane Central databases was completed for randomized control studies published between January 2000 to April 2020 for the following therapies: Rezum, Urolift, Aquablation, and prostatic artery embolization (PAE). Data on the following variables were included: International prostate symptom score (IPSS), maximum urinary flow rate, quality of life, and postvoid residual (PVR). Standard mean differences between treatments were compared through a meta-analysis using transurethral resection of the prostate (TURP) to assess differences in treatment effect.ResultsThere was no significant difference in outcomes between therapies for IPSS at the 3, 6, and 12-month follow ups. Although outcomes for Rezum were only available out to 3 months, there were no consistently significant differences in outcomes when comparing Aquablation versus PAE versus Rezum. TURP PVR was significantly better than Urolift at 3, 6, and 12 months. No significant differences in minor or major adverse events were noted.ConclusionAlthough significant differences in outcomes were limited, Aquablation and PAE were the most durable at 12 months. PAE has been well studied on multiple randomized control trials with minimal adverse events while Aquablation has limited high quality data and has been associated with bleeding-related complications.  相似文献   
3.
Introduction: In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement.

Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) – PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED).

Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.  相似文献   

4.
良性前列腺增生(BPH)是老年男性常见的泌尿系统疾病,其发病与前列腺慢性炎症之间存在显著相关。感染因子、尿液返流、代谢综合征、衰老过程和自身免疫应答在内的几种刺激,通过相应分子途径引起前列腺免疫细胞的组织定位和组成成分发生广泛改变,从而导致免疫系统失调,之后引发的组织损伤和缓慢愈合,导致了BPH发生和进展。本文通过总结良性前列腺增生与前列腺慢性炎症的相关性的临床研究结果,前列腺免疫细胞在病理生理机制层面与前两者之间的内在联系,以及抗炎药物对BPH-LUTS的干预作用,以其为BPH-LUTS的药物研发提供参考。  相似文献   
5.
PurposeLobular neoplasia (LN) detected on breast core needle biopsy is frequently managed with surgical excision because of concern for undersampled malignancy. The authors performed a systematic review and meta-analysis to estimate the risk for upgrade to malignancy in the setting of imaging-concordant classic LN diagnosed on core biopsy.MethodsPubMed and Embase were searched for original articles published from 1998 to 2020 that reported rates of upgrade to malignancy for classic LN, including atypical lobular hyperplasia (ALH) and classic lobular carcinoma in situ (LCIS). Two reviewers extracted study data and assessed the following quality criteria: exclusion of variant LCIS, exclusion of imaging-discordant lesions, and outcome reporting for ≥70% of lesions. For studies meeting all criteria, pooled risks for upgrade to any malignancy (invasive carcinoma or ductal carcinoma in situ) and invasive malignancy for all LN, ALH, and LCIS were estimated using random-effects models.ResultsFor 65 full-text articles included in the review, the risk for upgrade to any malignancy ranged from 0% to 45%. Among the 16 studies that met all quality criteria for the meta-analysis, pooled risks for upgrade to any malignancy were 3.1% (95% confidence interval [CI], 1.8%-5.2%) for all LN, 2.5% (95% CI, 1.6%-3.9%) for ALH, and 5.8% (95% CI, 2.9%-11.3%) for LCIS. Risks for upgrade to invasive malignancy were 1.3% (95% CI, 0.7%-2.4%) for all LN, 0.4% (95% CI, 0.0%-4.2%) for ALH, and 3.5% (95% CI, 2.0%-5.9%) for LCIS.ConclusionsThe risk for upgrade to malignancy for LN found on breast biopsy is low. Imaging surveillance can likely be offered as an alternative to surgical management for LN, particularly for ALH.  相似文献   
6.
PurposeTo determine if cone-beam CT and digital subtraction angiography analysis of pelvic arterial anatomy has predictive value for radiation exposure and technical success of prostatic artery embolization (PAE).Materials and MethodsThis prospective, nonrandomized, single-center study included 104 consecutive patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia. Cone-beam CT was performed in 160/208 (76.9%) hemipelves to determine prostatic artery (PA) origin. Classification of pelvic arterial tortuosity was possible in 73/104 (70.2%) patients. Learning curves of 2 interventionalists who performed 86.5% of PAEs were analyzed.ResultsTortuosity of pelvic arteries was classified as mild in 25 (34.2%) patients median age 64 years, moderate in 40 (54.8%) patients median age 69 years, and severe in 8 (11.0%) patients median age 70 years (mild vs moderate, P = .002; mild vs severe, P = .019); median fluoroscopy times were 24, 36, and 46 minutes (P = .008, P = .023); median contrast volumes were 105, 122.5, and 142 mL (P = .029, P = .064); and bilateral PAE rates were 84.0%, 77.5%, and 62.5% (P = .437), respectively. PA origin from superior vesical artery was most frequent (27.5%) and showed higher dose area product (median 402.4 vs 218 Gy ∙ cm2, P = .033) and fluoroscopy time (median 42.5 vs 27 min, P = .01) compared with PA origin from obturator artery, which was least frequent. Interventionalist experience revealed significant impact on procedure times (median 159 vs 130 min, P = .006).ConclusionsTortuosity of pelvic arteries was more frequent in older patients and predicted worse technical outcomes of PAE. PA origin from obturator artery was associated with lower dose area product and fluoroscopy time, especially compared with PA origin from superior vesical artery. Interventionalist experience showed significant influence on technical outcome.  相似文献   
7.
8.
目的探讨1 470 nm激光剜除治疗高危前列腺增生的手术技巧及临床效果。 方法回顾分析2018年6月至2018年9月中山大学附属第三医院泌尿外科采用1 470 nm激光治疗共89例高危前列腺增生患者的临床资料,年龄平均(68±3)岁,前列腺体积(57.4±2.6)ml。所有患者均采用"寻找层面,先易后难,剜切结合"的层面递进法思路行激光腔内前列腺剜除术,比较患者术中及术后情况。 结果89例均顺利完成手术,与术前相比,术后3个月患者最大尿流率明显增加,[(6.9±2.1) ml/s vs(19.8±3.6) ml/s]。国际前列腺症状评分显著好转,[(24.6±1.7) vs(8.0±1.2)]。术中无输血、无电切综合征、无直肠和膀胱穿孔病例,无输尿管损伤、大出血、心脑血管意外等严重并发症发生。 结论层面递进法激光剜除技术构想对于高危前列腺增生外科包膜层面的寻找、减少术后并发症有独到优势,且易于掌握,或可为业界同行提供一个新的思路。  相似文献   
9.
10.
To investigate the feasibility of arterial spin labeling (ASL) blood flow (BF) and its histogram analysis to distinguish early-stage nasopharyngeal carcinoma (NPC) from nasopharyngeal lymphoid hyperplasia (NPLH).Sixty-three stage T1 NPC patients and benign NPLH patients underwent ASL on a 3.0-T magnetic resonance imaging system. BF histogram parameters were derived automatically, including the mean, median, maximum, minimum, kurtosis, skewness, and variance. Absolute values were obtained for skewness and kurtosis (absolute value of skewness [AVS] and absolute value of kurtosis [AVK], respectively). The Mann–Whitney U test, receiver operating characteristic curve, and multiple logistic regression models were used for statistical analysis.The mean, maximum, and variance of ASL BF values were significantly higher in early-stage NPC than in NPLH (all P < 0.0001), while the median and AVK values of early-stage NPC were also significantly higher than those of NPLH (all P < 0.001). No significant difference was found between the minimum and AVS values in early-stage NPC compared with NPLH (P = 0.125 and P = 0.084, respectively). The area under the curve (AUC) of the maximum was significantly higher than those of the mean and median (P < 0.05). The AUC of variance was significantly higher than those of the other parameters (all P < 0.05). Multivariate analysis showed that variance was the only independent predictor of outcome (P < 0.05).ASL BF and its histogram analysis could distinguish early-stage NPC from NPLH, and the variance value was a unique independent predictor.  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