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   42051篇
  免费   3783篇
  国内免费   1079篇
耳鼻咽喉   2033篇
儿科学   829篇
妇产科学   798篇
基础医学   3055篇
口腔科学   1498篇
临床医学   4353篇
内科学   7064篇
皮肤病学   605篇
神经病学   2422篇
特种医学   1397篇
外国民族医学   9篇
外科学   8628篇
综合类   4914篇
现状与发展   2篇
预防医学   1222篇
眼科学   542篇
药学   2314篇
  21篇
中国医学   842篇
肿瘤学   4365篇
  2024年   103篇
  2023年   807篇
  2022年   1453篇
  2021年   2136篇
  2020年   1895篇
  2019年   1762篇
  2018年   1751篇
  2017年   1685篇
  2016年   1716篇
  2015年   1691篇
  2014年   2855篇
  2013年   2815篇
  2012年   2199篇
  2011年   2478篇
  2010年   1959篇
  2009年   2047篇
  2008年   2130篇
  2007年   2073篇
  2006年   1926篇
  2005年   1680篇
  2004年   1443篇
  2003年   1183篇
  2002年   963篇
  2001年   844篇
  2000年   697篇
  1999年   598篇
  1998年   446篇
  1997年   428篇
  1996年   336篇
  1995年   290篇
  1994年   307篇
  1993年   223篇
  1992年   221篇
  1991年   205篇
  1990年   162篇
  1989年   165篇
  1988年   153篇
  1987年   130篇
  1986年   138篇
  1985年   139篇
  1984年   125篇
  1983年   97篇
  1982年   114篇
  1981年   88篇
  1980年   74篇
  1979年   52篇
  1978年   37篇
  1977年   35篇
  1976年   23篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 155 毫秒
11.
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   

12.
??Objective    To observe the effects of lithium chloride pretreatment on cognitive ability of aged rats after oral and maxillofacial surgery. Methods    A total of 48 aged male SD rats??18 ~ 20 months old??weight 550 ~ 700 g?? were bought from the Experimental Animal Center of China Medical University . These rats were randomly divided into three groups??including the normal control group??group C??n=16????surgery and anesthesia group??group O??n=16????and lithium chloride preconditioning group??group L??n=16??.Rats in each group were randomly divided into two parts??one part was given Morris water maze test three days after the surgery and its characteristics of behavior tested. Another part was decapitated 24 h after the surgery and extracted and the hippocampus brain separated at the same time. Test expression content of IL-1β GSK-3β p-GSK-3β??ser9??in the hippocampus by Elisa and Western blotting detection method respectively. Results    Morris water maze test showed that??the first day after surgery??latencies of group L and O were significantly longer than group C??compared with group C in swimming distance?? latency and swim distances of group L were shorter than group O. With the comparison of multiple analysis of variance??differences were statistically significant??P??0.05??. Groups L and O in the second day were slightly shortened compared to the first day??on the third day after surgery it has also improved over the second day. Space exploration experiments in rats showed that??the dwell time of group C was significantly longer in the platform quadrant and the frequency of crossing the platform also increased compared with groups L and O. In addition??group L and group O were higher in IL-β levels than group C??the difference being statistically significant by analysis of variance??P??0.05????but group L was significantly lower compared with group O??the difference being statistically significant??P??0.05??. The content of GSK-3β of three groups were of no significant difference??P > 0.05????but p-GSK-3β??ser9??content was significantly lower in group L and O than in group C. The content of GSK-3β of group L was higher than in group O??the difference being statistically significant??P??0.05??. Conclusion    Pretreatment with lithium chloride in postoperative aged rats can inhibit the expression of inflammatory cytokines and increase GSK-3β phosphorylation in the hippocampus cells??so p-GSK-3β??ser9??upregulates and inhibites  the apoptosis of brain cells??thereby improved cognitive abilities after the cavity and maxillofacial surgery.  相似文献   
13.
正目前,临床上对于直肠癌常用的影像评估方法有MRI、螺旋CT、PET-CT、直肠腔内超声(ERUS)等。而MRI作为首选检查方式,对肿瘤位置、浸润深度、淋巴结转移、血管侵犯、环周切缘及周围器官侵犯等方面的评估均具有明显优势~([1-2])。通过MRI诊断淋巴结的方法通常是影像科医师逐层浏览每一幅图像,从中识别淋巴结的形状、界限及密度来判断,这种传统方式耗时较长且存在主观偏倚,导致  相似文献   
14.
《Foot and Ankle Surgery》2020,26(2):193-197
BackgroundThe aim of this study was to compare the radiographic and functional results between fixation and non-fixation in the Cotton osteotomy for the treatment of adult acquired flatfoot.MethodsA retrospective, case-controlled study of consecutive stage IIB posterior tibial tendon dysfunction (PTTD) patients treated with the same bony reconstructive surgery including cotton osteotomy between 2013 and 2017. Meary’s angle, the medial arch sag angle (MASA), and medial cuneiform cobb angle (MCCA) were evaluated pre-operation, at first weight bearing after surgery, and 12 months post operation.ResultsForty feet were included in the study. The cotton osteotomy utilized screw fixation (n = 20) or non-fixation technique (n = 20). No significant differences between groups were found in pre-operative and follow-up radiographic parameters, union rate, and functional results.ConclusionThe non-fixation with press fit technique is a reliable procedure for Cotton osteotomy and as effective as screw fixation.Level of evidenceLevel III, case control study  相似文献   
15.
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   
16.
目的探究肿瘤坏死因子-α(Tumornecrosis factor-α,TNF-α)-308基因对导管相关性脓毒症(Catheter related sepsis,CRS)患者病情的影响,旨在为临床治疗CRS提供科学依据。方法选取2017年7月-2018年10月于浙江大学医学院附属杭州市第一人民医院接受治疗的86例CRS患者为研究对象,按照是否并发多器官功能障碍综合征将患者分为试验组和对照组,对照组共48例,未并发多器官功能障碍综合征,试验组共38例,并发多器官功能障碍综合征,分析两组患者TNF-α-308基因多态性差异,使用多因素Logistic回归分析CRS患者并发多器官功能障碍综合征的危险因素。结果试验组GA基因型频率34.21%、AA基因型频率50.00%、高G等位基因频率18.42%均高于对照组,GG基因型频率52.63%、A等位基因频率28.95%均低于对照组,差异均具有统计学意义(P<0.05);多因素Logistic回归分析结果显示,低GG基因型频率、低G等位基因频率、高GA基因型频率、高AA基因型频率、高A等位基因频率是CRS患者并发多器官功能障碍综合征的危险因素(P<0.05)。结论TNF-α-308基因与CRS患者病情密切相关,GG基因型频率和G等位基因频率降低,GA基因型频率、AA基因型频率、A等位基因频率升高会加重患者的病情,增加多器官功能障碍综合征的发生风险,临床上应该加以重视。  相似文献   
17.
18.
19.
《The ocular surface》2020,18(1):108-113
PurposeAromatase inhibitors (AIs) limit the synthesis of oestrogen in peripheral tissues thus lowering levels of oestrogen. The primary aim was to evaluate whether women treated with AIs have altered dry eye symptoms and signs. A sub-aim was to investigate whether symptoms of dry eye in postmenopausal women were associated with symptoms of non-eye pain, ocular pain and self-rated pain perception.MethodsThis cross-sectional, observational, single visit study recruited 56 postmenopausal women (mean age 64.1 + 7.9 years) and 52 undergoing AI treatment (mean age 66.6 + 9.0). Ocular symptoms (OSDI, MGD14) and pain questionnaires (PSQ, OPAS) were administered and signs of dry eye and meibomian gland dysfunction were evaluated.ResultsAlmost half of each group reported dry eye symptoms, defined as OSDI>12 (48% control, 46% AI). The PSQ score was significantly higher in the AI group (p = 0.04). Neither frequency or severity of dry eye (or MGD) symptoms scores were significantly different between groups. In the AI group, meibomian gland expressibility score was worse (p = 0.003); there were no differences in any other signs. Higher OSDI scores were associated with higher OPAS eye-pain scores (r = 0.49, p < 0.001), but not OPAS non-eye pain (r = 0.09, p = 0.35). Pain perception (PSQ) showed a moderate positive association with OPAS eye-pain (r = 0.30, p = 0.003).ConclusionsIn this study elevated ocular symptoms were observed in both the AI treated and the untreated groups, with no difference between the groups. Women undergoing AI treatment for early stage breast cancer had worse meibum expressibility score and increased pain perception compared to an untreated group of women.  相似文献   
20.
Interstitial cystitis/bladder pain syndrome (IC/BPS) and vulvodynia are chronic pain syndromes that appear to be intertwined from the perspectives of embryology, pathology and epidemiology. These associations may account for similar responses to various therapies.  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