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   47888篇
  免费   2493篇
  国内免费   1110篇
耳鼻咽喉   267篇
儿科学   1371篇
妇产科学   224篇
基础医学   2429篇
口腔科学   99篇
临床医学   7151篇
内科学   9264篇
皮肤病学   253篇
神经病学   2493篇
特种医学   1341篇
外科学   4443篇
综合类   9629篇
预防医学   2908篇
眼科学   225篇
药学   5679篇
  48篇
中国医学   2190篇
肿瘤学   1477篇
  2024年   37篇
  2023年   571篇
  2022年   1258篇
  2021年   1859篇
  2020年   1714篇
  2019年   1343篇
  2018年   1402篇
  2017年   1538篇
  2016年   1793篇
  2015年   1697篇
  2014年   4138篇
  2013年   3913篇
  2012年   3475篇
  2011年   3552篇
  2010年   2784篇
  2009年   2410篇
  2008年   2310篇
  2007年   2345篇
  2006年   2094篇
  2005年   1716篇
  2004年   1364篇
  2003年   1145篇
  2002年   849篇
  2001年   809篇
  2000年   674篇
  1999年   586篇
  1998年   479篇
  1997年   443篇
  1996年   383篇
  1995年   333篇
  1994年   324篇
  1993年   228篇
  1992年   199篇
  1991年   205篇
  1990年   193篇
  1989年   148篇
  1988年   172篇
  1987年   132篇
  1986年   101篇
  1985年   142篇
  1984年   113篇
  1983年   59篇
  1982年   88篇
  1981年   75篇
  1980年   74篇
  1979年   55篇
  1978年   41篇
  1977年   39篇
  1976年   20篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.

Background

Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil–lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.

Methods

We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.

Results

Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18–1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50–3.72). Postoperative NLR measurements were not of prognostic significance.

Conclusions

Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery.  相似文献   
33.
目的 运用核磁共振弥散张量成像技术(DTI),从皮质脊髓束损伤程度评价的角度,探讨肾虚髓亏证与急性缺血性脑卒中运动功能缺损程度相关性,丰富中风病病机及证候诊断,拓宽缺血性脑卒中的中医药防治思路,为急性缺血性脑卒中肾虚髓亏证患者运动功能损伤程度提供临床依据,强调肾虚髓亏证在急性缺血性脑卒中运动功能损伤中的重要意义。方法 纳入符合诊断标准的90例病例,根据证候分别归入肾虚髓亏组和非肾虚髓亏组,每组各45例。每组患者均给予常规西药治疗。对两组患者入院后行弥散张量成像检测,同时分别于治疗前及治疗后14天,记录两组患者NIHSS评分、改良Barthel指数量表及简化Fugl-Meyer运动功能评分量表评分,比较两组病例发病时的轻重程度及治疗前后两组病例组间的恢复差异。结果 研究显示,治疗前肾虚髓亏组在NIHSS评分方面高于非肾虚髓亏组(P<0.05);治疗前肾虚髓亏组在改良Barthel指数量表及简化Fugl-Meyer运动功能评分方面低于非肾虚髓亏组(P<0.05)。治疗前后NIHSS评分、改良Barthel指数评分及简化Fugl-Meyer运动功能评分改善情况,非肾虚髓亏组要优于肾虚髓亏组(P<0.05)。治疗前两组患者在健侧内囊后肢及大脑脚外侧处FA值及ADC值无明显差异;肾虚髓亏组在患侧内囊后肢及大脑脚外侧处FA值及ADC值均低于非肾虚髓亏组(P<0.05)。相关性分析得出,两组患者患侧内囊后肢FA值与患者治疗前NIHSS评分呈负相关;两组患者患侧内囊后肢FA值与患者改良Barthel指数评分及简化Fugl-Meyer运动功能评分呈正相关;肾虚髓亏组患者患侧内囊后肢FA值与肾虚髓亏证中医证候评分呈负相关。结论 肾虚髓亏是急性缺血性脑卒中运动功能障碍的重要病机。研究结果显示,两组皮质脊髓束损伤程度与神经功能及运动功能损伤存在相关性,且肾虚髓亏组在皮质脊髓束的损伤程度方面与其中医证候评分呈负相关。  相似文献   
34.
Objective: The objective of this study is to evaluate the efficacy and safety of the clearing the lung and dissipating phlegm method in the treatment of acute exacerbation of chronic obstructive pulmonary disease(COPD) and to provide evidence for the treatment of the disease. Materials and Methods: Literature was searched from the United States National Library of Medicine(PubMed), Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database(Wanfang), and the Full?Text Database of Chinese Scientific and Technical Periodicals(VIP).A comprehensive collection was made of randomized controlled trials(RCTs) before June 2018, in which the treatment groups used either the clearing the lung and dissipating phlegm formulas only or combined it with routine Western medicine therapy, and the control group adopted routine Western medicine therapy only for the acute exacerbation of COPD. The Cochrane risk of bias method was used to evaluate the quality of the literature. The data were analyzed and retrieved independently by two reviewers before meta?analysis was carried out with RevMan 5.3 software to evaluate the primary outcome measures, including the total clinical effective rate, and the secondary outcome measures such as the pulmonary function(forced vital capacity [FVC], forced expiratory volume in the 1 s [FEV1], percentage of FEV1 [FEV1%], and FEV1/FVC)and blood gases(PaO_2 and PaCo_2). Results: A total of 13 RCTs involving 990 patients(496 in the treatment group and 494 in the control group)were included in this study. Meta?analysis revealed significant difference in the efficacy of the group that adopted solely the routine Western medicine method and the group that combined the Western medicine with the clearing the lung and dissipating phlegm method. Outcome measures including the pulmonary function(FVC, FEV1, FEV1%, and FEV1/FVC) and the blood gases(PaO_2 and PaCo_2) were significantly improved as compared to the control group(P 0.00001). However, adverse effects in the treatment group using combined traditional Chinese medicine were not reported due to the short observation time of the study. Conclusion: The clearing the lung and dissipating phlegm method can improve the efficacy in the treatment of acute exacerbation of COPD, the outcome measures of the pulmonary function and the blood gases,as well as the life quality of the patients. However, due to the fact that the existing studies are generally of poor quality in which randomization and its implementation were not properly carried out, more high?quality RCTs are necessary to confirm the findings of this study.  相似文献   
35.
目的:探究清热化瘀汤联合依达拉奉对急性脑出血患者血清超敏C反应蛋白(hs-CRP)、血浆S100β蛋白和神经元特异性烯醇化酶(NSE)的影响。方法:选择2017年5月—2019年5月在我院神经内科就诊符合纳入标准的80例急性脑出血患者,随机分为联合组(40例)和依达拉奉组(40例),两组均给予基础治疗和依达拉奉静脉滴注治疗,联合组则在此基础上加用清热化瘀汤。观察并比较两组的临床疗效、神经功能缺损程度评分(NIHSS)、格拉斯哥昏迷评分(GCS)、hs-CRP、S100β蛋白和NSE水平及脑血肿量。结果:联合组的总有效率为95%(38/40),显著高于依达拉奉组的总有效率75%(30/40)(P<0.05)。治疗后,两组NIHSS评分降低,GCS评分升高,且联合组NIHSS评分明显低于依达拉奉组(P<0.05),GCS评分高于依达拉奉组(P<0.05)。治疗后,两组hs-CRP、S100β蛋白和NSE水平及均脑血肿量均低于治疗前,且联合组hs-CRP、S100β蛋白和NSE水平及脑血肿量明显低于依达拉奉组(P<0.05)。结论:清热化瘀汤联合依达拉奉对急性脑出血患者具有良好的疗效,可显著改善其神经缺损,降低hs-CRP、S100β蛋白和NSE水平及脑血肿量。  相似文献   
36.
BackgroundAbnormalities of chromosome 3 in myelodysplastic syndromes (MDS), that is, inversion 3 (inv[3]), translocation 3q (t[3q]), or deletion 3q (del[3q]), are defined as poor-risk karyotypes in the Revised International Prognostic Scoring System (IPSS-R). The objective of this study was to further define the outcomes of patients with MDS with chromosome 3 abnormalities and address the impact of hypomethylating agent (HMA) therapy on this patient subset.Patients and MethodsThrough the MDS Clinical Research Consortium, we identified 411 patients with chromosome 3 abnormalities and MDS or oligoblastic acute myeloid leukemia (20%-30% blasts).ResultsSpecific chromosome 3 aberrations and cytogenetic complexity were predictive of survival; patients with t(3q) and isolated chromosome 3 had improved overall survival (OS), albeit still poor, whereas patients with complex cytogenetics, including those with 3p abnormalities, had inferior OS. Overall response rates to HMAs among this patient population were similar to those of patients with nonchromosome 3–MDS (52%, with a 25% complete remission rate), although with higher response rates in decitabine-treated patients (69% vs. 45%, P = .008). HMA therapy improved the OS of patients with higher-risk MDS compared with intensive chemotherapy (median OS of 15.5 vs. 8.2 months; P = .017). This improvement remained significant in multivariate analyses (hazard ratio, 0.60; P = .018); however, there were no chromosome 3 aberrations among this subgroup predictive of improved response rates to or survival from HMAs.ConclusionPatients with MDS with chromosome 3 abnormalities represent a cytogenetic cohort with poor OS, and there is an urgent need for novel therapeutic strategies.  相似文献   
37.
Coronavirus disease 2019 is a major threat to public health globally. Though its pathogenesis has not been fully elucidated, angiotensin-converting enzyme 2 (ACE2) has been recently identified as a receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the cell. Here, we aimed to clarify the potential role of ACE2 in SARS-CoV-2-induced acute lung injury and its underlying mechanism. As a receptor for coronavirus, ACE2 mediates the entry of SARS-CoV-2 into cells in a similar way as for severe acute respiratory syndrome coronavirus (SARS-CoV). The high binding affinity of SARS-CoV-2 to ACE2 correlates with its efficient spread among humans. On the other hand, ACE2 negatively regulates the renin-angiotensin-aldosterone system (RAAS) primarily by converting angiotensin II to angiotensin 1–7, which exerts a beneficial effect on coronavirus-induced acute lung injury. Human recombinant ACE2 has been considered as a potential therapy for SARS-CoV-2 by blocking virus entry and redressing the imbalance of RAAS in SARS-CoV-2 infection. The level of ACE2 expression can be upregulated by treatment with an ACE inhibitor (ACEI) or angiotensin Ⅱ type 1 receptor blocker (ARB). To date, no evidence shows that ACEIs or ARBs increase the susceptibility and mortality of patients infected with SARS-CoV-2, and hence, it is not advisable to discontinue such drugs in patients with cardiovascular disease.  相似文献   
38.
39.
《中国现代医生》2020,58(18):93-97
目的 探讨不同介入方案治疗急性下肢静脉血栓(DVT)的临床效果与安全性。方法 选取我院2015年1月~2019年12月介入科收治的急性DVT患者54例作为研究对象,按照治疗方式的不同分为研究组27例和对照组27例。研究组采用血管腔内综合治疗,对照组采用导管介导溶栓治疗,比较两组患者疗效评价、治疗前后膝上、下15 cm与患肢周径差、治疗前后皮肤肿胀张力、静脉通畅率、住院时间和并发症发生情况。结果 经治疗后研究组患者膝上、下15 cm与患肢周径差均短于对照组(P0.05);经治疗后研究组患者皮肤肿胀张力恢复程度显著优于对照组(P0.05);经治疗后研究组患者静脉通畅率显著高于对照组(P0.05);研究组治疗有效率显著高于对照组(P0.05);研究组患者住院时间明显少于对照组,且其并发症发生率显著低于对照组(P0.05)。结论 血管腔内综合介入治疗能够有效改善患者下肢症状,提高DVT恢复情况,降低并发症的发生,从而有效提高患者生活质量,为临床治疗DVT提供重要参考。  相似文献   
40.
目的:探讨糖皮质激素联合特布他林对慢性阻塞性肺疾病(慢阻肺)急性加重期患者的疗效。方法:选取我院自2018年1月—2019年7月慢阻肺急性加重期患者200例为观察对象,按照随机数表法分为对照组和观察组,各100例。两组均给予常规对症治疗,对照组在此基础上给予特布他林雾化吸入治疗,观察组在对照组基础上给予糖皮质激素普米克令舒雾化吸入治疗,对比两组疗效、血清炎症因子、肺功能。结果:观察组总有效率为98.00%(98/100),高于对照组的90.00%(90/100)(P<0.05);治疗后两组IL-8、TNF-α均下降,其中观察组低于对照组(P<0.05);治疗后两组FEV1、FVC、PEF升高,其中观察组高于对照组(P<0.05)。结论:糖皮质激素联合特布他林能够减轻慢阻肺急性加重期患者的机体炎症反应,改善肺功能,提高疗效,具有较高应用价值。  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