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   193157篇
  免费   14398篇
  国内免费   4856篇
耳鼻咽喉   1567篇
儿科学   2823篇
妇产科学   3436篇
基础医学   25400篇
口腔科学   3645篇
临床医学   13132篇
内科学   26224篇
皮肤病学   2473篇
神经病学   12812篇
特种医学   6671篇
外国民族医学   2篇
外科学   16753篇
综合类   25663篇
现状与发展   21篇
一般理论   9篇
预防医学   15572篇
眼科学   2411篇
药学   26613篇
  57篇
中国医学   13107篇
肿瘤学   14020篇
  2024年   283篇
  2023年   2409篇
  2022年   4041篇
  2021年   8707篇
  2020年   6841篇
  2019年   7163篇
  2018年   7343篇
  2017年   7427篇
  2016年   7236篇
  2015年   6919篇
  2014年   8108篇
  2013年   11933篇
  2012年   9657篇
  2011年   11688篇
  2010年   7438篇
  2009年   7440篇
  2008年   8940篇
  2007年   9990篇
  2006年   9351篇
  2005年   8627篇
  2004年   7410篇
  2003年   6692篇
  2002年   5189篇
  2001年   4645篇
  2000年   3902篇
  1999年   3350篇
  1998年   2739篇
  1997年   2775篇
  1996年   2478篇
  1995年   2140篇
  1994年   2086篇
  1993年   1737篇
  1992年   1601篇
  1991年   1506篇
  1990年   1298篇
  1989年   1080篇
  1988年   1033篇
  1987年   927篇
  1986年   863篇
  1985年   1255篇
  1984年   1024篇
  1983年   767篇
  1982年   794篇
  1981年   645篇
  1980年   637篇
  1979年   510篇
  1978年   315篇
  1977年   273篇
  1976年   253篇
  1975年   194篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
21.
22.
Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) in particulate matter that has a diameter of ≤2.5 μm (PM2.5). Studies have demonstrated that BaP exposure causes oocyte meiotic arrest in mice. However, whether BaP exposure also affects oocyte maturation in offspring remains unclear. To test this, female mice were administered BaP before pregnancy to generate BaP-exposed offspring. Our findings showed that BaP exposure reduced the in vitro maturation and increased the abnormalities of meiotic apparatus in offspring oocytes. In addition, BaP exposure reduced the mitochondrial content and intracellular ATP generation, induced early apoptosis, increased reactive oxidative species accumulation and the genomic DNA 5-methylcytosine (5mc) level in offspring oocytes. Along with the abovementioned defective parameters, maternal BaP exposure further compromised the embryo developmental competence of offspring oocytes. In summary, our study demonstrated that maternal BaP exposure compromised offspring oocyte maturation and quality.  相似文献   
23.
《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   
24.

Purpose

Endovascular treatment with mechanical thrombectomy devices demonstrated high recanalization rates but functional outcome did not correlate with high rates of recanalization obtained. Patient selection prior to the endovascular treatment is very important in the final outcome of the patient. The primary aim of our study was to evaluate the prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and Pons-Midbrain Index (PMI) scores in patients with Basilar Artery Occlusion (BAO) treated with successful angiographic recanalization after mechanical thrombectomy.

Methods

Retrospective single-center study including 18 patients between 2008 and 2013 who had acute basilar artery occlusion managed with endovascular treatment within 24 hours from symptoms onset and with successful angiographic recanalization. The patients were initially classified into two groups according to clinical outcome and mortality at 90 days. For analysis we also divided patients into groups based on pc-ASPECTS (≥8vs.< 8) and PMI (≥3vs.< 3) on non-contrast CT (NCCT) and CT Angiography Source Images (CTASI). Imaging data were correlated to clinical outcome and mortality rate.

Results

CTASI pc-ASPECTS, dichotomized at < 8 versus≥8, was associated with a favorable outcome (RR: 2.6; 95% CI: 1.3-5.2) and a reduced risk of death (RR: 6.5: 95% CI: 7.8-23.3). All patients that survived and were functionally independent had pc-ASPECTS score≥8. None of the 5 patients with CTASI pc-ASPECTS score less than 8 survived.

Conclusion

PC-ASPECTS on CTASI is helpful for predicting functional outcome after BAO recanalization with endovascular treatment. These results should be validated in a randomized controlled trial in order to decide whether or not to treat a patient with BAO.  相似文献   
25.
中药生产过程质量控制关键技术研究进展   总被引:10,自引:8,他引:2  
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。  相似文献   
26.
目的:探讨负压创面治疗技术(Vacuum assisted closure,VAC)结合游离植皮治疗儿童大面积皮肤缺损疗效及对患儿生活质量的影响。方法:选取2015年2月-2019年2月笔者医院收治的60例大面积皮肤缺损患儿作为研究对象,按照随机数表法分为干预组和对照组,每组30例。对照组采用游离植皮术治疗,干预组在对照组的基础上结合VAC治疗,以皮片成活时间、皮片成活率、换药次数及住院天数评估疗效,以长海痛尺分级法评估患儿疼痛等级,以抑郁自评量表(Self-rating depression scale,SDS)、焦虑自评量表(Self-rating anxiety scale,SAS)评估患儿心理状态,以术后不良反应发生率评估患儿预后情况,以自制生活质量表评估患儿生活质量水平。结果:干预组患儿皮片成活时间、换药次数与住院天数均小于对照组,差异有统计学意义(P<0.05)。干预组患儿皮片成活率为93.33%高于对照组的76.67%,差异有统计学意义(P<0.05)。干预组治疗后疼痛感、SDS与SAS评分低于治疗前,且低于对照组,差异有统计学意义(P<0.05)。干预组患儿术后不良反应发生率为6.67%显著低于对照组23.33%,差异有统计学意义(P<0.05)。两组治疗前活动能力、心理健康及社交能力均低于治疗后,干预组治疗后活动能力、心理健康及社交能力均高于对照组(P<0.05)。结论:VAC结合游离植皮治疗儿童大面积皮肤缺损疗效显著,能有效降低患儿生理疼痛与心理焦虑,减少伤口感染等不良反应的发生,提高患儿生活质量,具有推广价值。  相似文献   
27.
《中国现代医生》2020,58(29):24-27+封三
目的 探讨肝癌组织中LncRNA TINCR 表达水平对术后长期生存的影响。方法 回顾性分析2013 年4 月~2016 年2 月间在本院接受手术治疗的157 例肝细胞肝癌患者的临床资料。RT-PCR 法检测肝癌标本内LncRNA TINCR 表达水平,采用ROC 曲线和Kaplan-Meier 法分析LncRNA TINCR 表达水平对肝癌术后长期生存的影响。结果 肝癌组织LncRNA TINCR 表达水平对术后长期生存预测的曲线下面积(AUC)为0.812,特异度为73.77%,灵敏度为79.17%,最佳判读值为1.89(P<0.0001)。根据ROC 曲线分析结果,将肝癌组织LncRNA TINCR 相对表达水平大于1.89 的93 例(59.24%)患者纳入高表达组,而肝癌组织LncRNA TINCR 相对表达水平小于或等于1.89的64 例(40.76%)患者纳入低表达组。Kaplan-Meier 法生存分析发现高表达组术后3 年内有76 例患者死亡,3 年总生存率为18.28%(17/93);低表达组术后3 年内有20 例患者死亡,3 年总生存率为68.75%(44/64),低表达组3 年总生存率明显优于高表达组(P<0.0001,两组间死亡风险比为3.7534,95%可信区间为2.5158~5.6000)。结论 肝癌组织LncRNA TINCR 表达水平与肝癌术后长期生存显著相关,LncRNA TINCR 表达水平升高则预示着预后不佳。  相似文献   
28.
BackgroundTumor mutation burden (TMB) as a prognostic marker for immunotherapy has shown prognostic value in many cancers. However, there is no systematic investigation on TMB in papillary thyroid carcinoma (PTC).MethodsBased on the somatic mutation data of 487 PTC patients from The Cancer Genome Atlas (TCGA), TMB was calculated, and we classified the samples into high-TMB (H-TMB) and low-TMB (L-TMB) groups. Bioinformatics methods were used to explore the characteristics and potential mechanism of TMB in PTC.ResultsHigh TMB predicts shorter progression-free survival (PFS) (P < 0.001). TMB was positively correlated with age, stage, tumor size, metastasis, the male sex and tall cell PTC. Compared to the L-TMB group, the H-TMB group presented with lower immune cell infiltration, a higher proportion of tumor-promoting immune cells (M0 macrophages, activated dendritic cells and monocytes) and a lower proportion of antitumor immune cells (M1 macrophages, CD8+ T cells and B cells). Additionally, the characteristics displayed by different TMB groups were not driven by critical driver mutations such as BRAF and RAS.ConclusionsPTC patients with high TMB have a worse prognosis. By stratifying PTC patients according to their TMB, advanced PTC patients who are candidates for immunotherapy could be selected.  相似文献   
29.
30.
Introduction: Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype associated with an increased risk of recurrence and cancer-related death. Unlike hormone receptor-positive or HER2-positive breast cancers, there are limited targeted therapies available to treat TNBC and cytotoxic chemotherapy remains the mainstay of treatment. Sacituzumab govitecan (IMMU-132) is an antibody-drug conjugate targeting Trop-2 expressing cells and selectively delivering SN-38, an active metabolite of irinotecan.

Areas covered: This review covers the mechanism of action, safety and efficacy of sacituzumab govitecan in patients with previously treated, metastatic TNBC. Additionally, efficacy data in other epithelial malignancies is included based on a PubMed search for ‘sacituzumab govitecan’ and ‘clinical trial’.

Expert opinion: Sacituzumab govitecan has promising anti-cancer activity in patients with metastatic TNBC previously treated with at least two prior lines of systemic therapy based on a single arm Phase I/II clinical trial. A confirmatory Phase III randomized clinical trial is ongoing. Sacituzumab govitecan has a manageable side effect profile, with the most common adverse events being nausea, neutropenia, and diarrhea. The activity of sacituzumab govitecan likely extends beyond TNBC with promising early efficacy data in many other epithelial cancers, including hormone receptor-positive breast cancer.  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