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   40477篇
  免费   3223篇
  国内免费   1181篇
耳鼻咽喉   191篇
儿科学   897篇
妇产科学   516篇
基础医学   6373篇
口腔科学   823篇
临床医学   2794篇
内科学   6235篇
皮肤病学   708篇
神经病学   3502篇
特种医学   617篇
外国民族医学   5篇
外科学   3187篇
综合类   5371篇
现状与发展   4篇
预防医学   1881篇
眼科学   487篇
药学   6303篇
  4篇
中国医学   1976篇
肿瘤学   3007篇
  2023年   706篇
  2022年   1252篇
  2021年   1811篇
  2020年   1376篇
  2019年   1542篇
  2018年   1523篇
  2017年   1415篇
  2016年   1283篇
  2015年   1360篇
  2014年   2219篇
  2013年   2455篇
  2012年   2039篇
  2011年   2471篇
  2010年   1957篇
  2009年   1990篇
  2008年   1991篇
  2007年   1773篇
  2006年   1645篇
  2005年   1536篇
  2004年   1443篇
  2003年   1254篇
  2002年   1083篇
  2001年   819篇
  2000年   797篇
  1999年   697篇
  1998年   562篇
  1997年   574篇
  1996年   501篇
  1995年   467篇
  1994年   401篇
  1993年   291篇
  1992年   241篇
  1991年   246篇
  1990年   185篇
  1989年   155篇
  1988年   167篇
  1987年   132篇
  1986年   143篇
  1985年   288篇
  1984年   304篇
  1983年   239篇
  1982年   269篇
  1981年   214篇
  1980年   198篇
  1979年   181篇
  1978年   135篇
  1977年   94篇
  1976年   103篇
  1975年   91篇
  1973年   71篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
This study aimed to understand the perceived effects of the COVID-19 pandemic on physical activity, recreation walking, and use of recreational facilities; and if the COVID-19 pandemic amplified disparities in physical activity, recreational walking, and use of recreational facilities related to the levels of neighborhood disadvantage. Recreational walking and the use of neighborhood streets and green spaces significantly decreased in high deprivation areas but not in low deprivation areas during the pandemic. While COVID-19 has negatively affected overall recreational activities, the inequitable impact on recreational walking and use of outdoor recreational facilities has been more evident in disadvantaged neighborhoods with greater deprivation.  相似文献   
992.
目的:观察健脾益气中药对结直肠炎病变后诱发结直肠癌小鼠白细胞介素(Interleukin,IL)-6和表皮细胞生长因子(Epidermal Growth Factor,EGF)蛋白的影响。方法:将30只雄性C57BL/6小鼠随机分为对照组、模型组和治疗组,每组10只。采用偶氮氧化甲烷/葡聚糖硫酸钠方法建立结直肠炎相关结直肠癌小鼠模型,治疗组以加减四君子汤颗粒加蒸馏水配成溶液,药物质量浓度19.92%,3.32 g/kg灌胃,模型组以蒸馏水灌胃。4周后处死各组小鼠并留取血液和结直肠组织组织标本,酶联免疫吸附试验(Enzyme-linked immunosorbent method,ELISA)法检测血清IL-6浓度,苏木精-伊红染色法(Hematoxylin-eosin Staining,简称HE染色法)染色镜下观察小鼠结肠组织病理变化,Western-blot法检测EGF蛋白表达。结果:健脾益气治疗组小鼠的体质量较模型组明显增加,差异有统计学意义(P<0.01);治疗组小鼠血清IL-6表达量比模型组显著下降,差异有统计学意义(P<0.01);治疗组小鼠的EGF蛋白表达显著降低,与模型组比较,差异均有统计学意义(P<0.05)。结论:健脾益气中药能增加结直肠炎病变后诱发结直肠癌小鼠的体质量,减少炎症因子IL-6的表达和降低EGF蛋白表达,可为健脾益气中药抗结肠癌临床应用提供科学依据。  相似文献   
993.
We evaluated the efficacy of rehabilitation therapy with Hybrid Assistive Limb® (HAL; hereafter HAL therapy) in three patients diagnosed with sporadic inclusion body myositis (sIBM) who were hospitalized to undergo HAL therapy. Among them, one patient participated in eight courses and the other two in two courses of HAL therapy between 2017 and 2020. We determined the mean rate of improvement in two-minute walking distance and 6 m walking speed at the time of hospital discharge. After HAL therapy, we confirmed the patients’ desire to continue the use of HAL. In one patient, we observed improvements of 146.0% and 120.0% in two-minute walk and 6 m walking speed, respectively, after the first course of HAL therapy; these values are 133.7% and 130% after the eighth course of HAL therapy. These values exceeded 90% in the other two patients after the second course of HAL therapy. HAL therapy maintained both quantity and quality of ambulation and showed positive psychological effects on patient conditions because it reduces exercise load and facilitates safety. While HAL therapy might be effective in maintaining and improving ambulation in patients with sIBM, we should consider to discontinue HAL therapy as it increased risk of falling.  相似文献   
994.
995.
996.
997.
PurposeTo assess the prediction of the response to photodynamic therapy (PDT) in chronic central serous chorioretinopathy (CSCR) based on spectral-domain optical coherence tomography (SD-OCT) images using deep learning (DL).MethodsRetrospective study including 216 eyes of 175 patients with CSCR and persistent subretinal fluid (SRF) who underwent half-fluence PDT. SD-OCT macular examination was performed before (baseline) and 3 months after treatment. Patients were classified into groups by experts based on the response to PDT: Group 1, complete SRF resorption (n = 100); Group 2, partial SRF resorption (n = 66); and Group 3, absence of any SRF resorption (n = 50). This work proposes different computational approaches: 1st approach compares all groups; 2nd compares groups 1 vs. 2 and 3 together; 3rd compares groups 2 vs. 3.ResultsThe mean age was 55.6 ± 10.9 years and 70.3% were males. In the first approach, the algorithm showed a precision of up to 57% to detect the response to treatment in group 1 based on the initial scan, with a mean average accuracy of 0.529 ± 0.035. In the second model, the mean accuracy was higher (0.670 ± 0.046). In the third approach, the algorithm showed a precision of 0.74 ± 0.12 to detect the response to treatment in group 2 (partial SRF resolution) and 0.69 ± 0.15 in group 3 (absence of SRF resolution).ConclusionDespite the high clinical variability in the response of chronic CSCR to PDT, this DL algorithm offers an objective and promising tool to predict the response to PDT treatment in clinical practice.  相似文献   
998.
背景与目的恶性胸腔积液(malignant plural effusion, MPE)是液体活检基因检测的常用标本来源,本研究评估一种从大体积MPE中分离肿瘤细胞方法的分离效果及其在基因检测中的应用前景。方法收集20例伴MPE的晚期肺癌患者一次胸腔积液引流的全部MPE(> 500 mL),联合运用细胞分离介质Percoll和Ficoll分离肿瘤细胞,统计分离情况。对其中既往行组织基因检测的肺腺癌患者,分别使用胸腔积液上清游离DNA(tumor derived DNA from pleural effusion supernatant, etDNA),总细胞DNA及分离肿瘤细胞DNA(DNA from tumor cells in pleural effusion, ETC-DNA)3种成分进行二代基因测序,比较检测情况。结果从MPE中分离得到细胞中位数量8.50×104个(上下四分位间距9.25×103-3.75×105),肿瘤细胞纯度85.50%±5.80%。对10例既往行组织表皮生长因子受体(epidermal growth factor receptor, EGFR)基因检测的患者,etDNA、总细胞DNA及ETC-DNA EGFR基因突变检出率分别为70.00%、50.00%、70.00%。ETC-DNA基因检测阳性率与组织(P > 0.999, kappa=1.000)和etDNA(P > 0.999, kappa=1.000)一致性均良好。etDNA、总细胞DNA、ETC-DNA EGFR基因突变中位丰度分别为16.05%(4.78%-43.06%)、1.09%(0.00%-2.39%)和33.02%(18.50%-76.70%)。ETC-DNA检测丰度倾向高于etDNA,但差异无统计学意义。结论该提取方法可以有效地从大体积MPE中分离出大量高纯度肿瘤细胞,利用提取出的肿瘤细胞进行基因检测可能可以提高基因检测效能,值得进一步研究。  相似文献   
999.
BACKGROUND Pathological complete response(pCR) is rare in hormone receptor-positive(HR+)HER2-negative breast cancer(BC) treated with either endocrine therapy(ET) or chemotherapy. Radical resection of locoregional relapse, although potentially curative in some cases, is challenging when the tumor invades critical structures.The oral cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with ET has obtained a significant increase in objective response rates and progression-free survival in patients with advanced BC and is now being evaluated in the neoadjuvant setting. We present a clinical case of a patient with an inoperable locoregional relapse of HR+ HER2-negative BC who experienced p CR after treatment with palbociclib.CASE SUMMARY We report the clinical case of a 60-year-old patient who presented with an inoperable locoregional relapse of HR+, HER2-negative BC 10 years after the diagnosis of the primary tumor. During a routine follow-up visit, breast magnetic resonance imaging and positron emission tomography/computed tomography revealed a 4-cm lesion in the right subclavicular region, infiltrating the chest wall and extending to the subclavian vessels, but without bone or visceral involvement. Treatment was begun with palbociclib plus letrozole, converting the disease to operability over a period of 6 mo. Surgery was performed and a p CR achieved. Of note, during treatment the patient experienced a very uncommon toxicity characterized by burning tongue and glossodynia associated with dysgeusia, paresthesia, dysesthesia, and xerostomia. A reduction in the dose of palbociclib did not provide relief and treatment with the inhibitor was thus discontinued, resolving the tongue symptoms. Laboratory exams were unremarkable. Given that this was a late relapse, the tumor was classified asendocrine-sensitive, a condition associated with high sensitivity to palbociclib.CONCLUSION This case highlights the potential of the cyclin-dependent kinase 4/6 inhibitor plus ET combination to achieve pCR in locoregional relapse of BC, enabling surgical resection of a lesion initially considered inoperable.  相似文献   
1000.
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