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   276239篇
  免费   23602篇
  国内免费   7001篇
耳鼻咽喉   4294篇
儿科学   5664篇
妇产科学   3947篇
基础医学   25093篇
口腔科学   15687篇
临床医学   24436篇
内科学   25783篇
皮肤病学   2612篇
神经病学   11692篇
特种医学   9694篇
外国民族医学   31篇
外科学   38946篇
综合类   42188篇
现状与发展   15篇
一般理论   24篇
预防医学   30549篇
眼科学   2189篇
药学   23191篇
  375篇
中国医学   27797篇
肿瘤学   12635篇
  2024年   1065篇
  2023年   5014篇
  2022年   9486篇
  2021年   12557篇
  2020年   12199篇
  2019年   13484篇
  2018年   12059篇
  2017年   10635篇
  2016年   9916篇
  2015年   9651篇
  2014年   18109篇
  2013年   19081篇
  2012年   16019篇
  2011年   17482篇
  2010年   14351篇
  2009年   12879篇
  2008年   12076篇
  2007年   12201篇
  2006年   10613篇
  2005年   9470篇
  2004年   7915篇
  2003年   6996篇
  2002年   5477篇
  2001年   4667篇
  2000年   4177篇
  1999年   3462篇
  1998年   2791篇
  1997年   2615篇
  1996年   2177篇
  1995年   1964篇
  1994年   1832篇
  1993年   1526篇
  1992年   1418篇
  1991年   1270篇
  1990年   1080篇
  1989年   1026篇
  1988年   956篇
  1987年   829篇
  1986年   781篇
  1985年   2056篇
  1984年   2264篇
  1983年   1444篇
  1982年   1922篇
  1981年   1356篇
  1980年   1172篇
  1979年   1086篇
  1978年   896篇
  1977年   673篇
  1976年   801篇
  1975年   523篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
951.
Over the past years, research attention has been focusing more on waste-derived, naturally derived, and renewable materials, in the view of a more sustainable economy. In this work, different topical formulations were obtained from the valorization of marine and agro-industrial by-products and the use of Carbopol 940 as gelling agent. In particular, the combination of extracts obtained from the marine snail, Rapanosa venosa, with Cladophora vagabunda and grape pomace extracts, was investigated for wound healing purposes. Rapana venosa has demonstrated wound healing properties and antioxidant activity. Similarly, grape pomace extracts have been shown to accelerate the healing process. However, their synergic use has not been explored yet. To this aim, four different formulations were produced. Three formulations differed for the presence of a different extract of Rapana venosa: marine collagen, marine gelatin, and collagen hydrolysate, while another formulation used mammalian gelatin as further control. Physico-chemical properties of the extracts as well as of the formulations were analyzed. Furthermore, thermal stability was evaluated by thermogravimetric analysis. Antioxidant capacity and biological behavior, in terms of cytocompatibility, wound healing, and antimicrobial potential, were assessed. The results highlighted for all the formulations (i) a good conservation and thermal stability in time, (ii) a neutralizing activity against free radicals, (iii) and high degree of cytocompatibility and tissue regeneration potential. In particular, collagen, gelatin, and collagen hydrolysate obtained from the Rapana venosa marine snail represent an important, valuable alternative to mammalian products.  相似文献   
952.
Increasing evidence shows the nasal epithelium to be the initial site of SARS-CoV-2 infection, and that early and effective immune responses in the upper respiratory tract (URT) limit and eliminate the infection in the URT, thereby preventing infection of the lower respiratory tract and the development of severe COVID-19. SARS-CoV-2 interferes with innate immunity signaling and evolves mutants that can reduce antibody-mediated immunity in the URT. Recent genetic and immunological advances in understanding innate immunity to SARS-CoV-2 in the URT, and the ability of prior infections as well as currently available injectable and potential intranasal COVID-19 vaccines to generate anamnestic adaptive immunity in the URT, are reviewed. It is suggested that the more detailed investigation of URT immune responses to all types of COVID-19 vaccines, and the development of safe and effective COVID-19 vaccines for intranasal administration, are important needs.  相似文献   
953.
Patients with head and neck cancer report high unmet psychosocial needs as they undergo lifesaving treatments that can significantly alter their appearance and cause functional impairments. This qualitative analysis of recordings of 88 pre- and post-surgical consultations involving 20 patients respond to the need for empirical studies of patient–provider conversations about body image concerns. It indicates that the emphasis on concerns about survival, cure, and physical recovery during clinical consultations may leave concerns about the impacts of surgery on appearance and function unexplored and even silenced. The interviews with patients and medical team members that complement the analysis of the recordings suggest that an emphasis on survival, cure, and physical recovery can respond to the need for reassurance in the context of serious illness. However, it can also be problematic as it contributes to the silencing of patients’ concerns and to a potential lack of preparedness for the consequences of surgery. The results of this study can contribute to raising surgeons’ awareness of the interactional dynamics during clinical consultations. Moreover, the results highlight the unique role that surgeons can play in validating patients’ psychosocial concerns to support patients’ rehabilitation in both physical and psychosocial domains.  相似文献   
954.
Background: To investigate associations between psychological problems and the use of healthcare and informal care and total costs among head and neck cancer (HNC) patients. Method: Data were used of the NETherlands QUality of Life and Biomedical Cohort study. Anxiety and depression disorder (diagnostic interview), distress, symptoms of anxiety and depression (HADS), and fear of cancer recurrence (FCR) and cancer worry scale (CWS) were measured at baseline and at 12-month follow-up. Care use and costs (questionnaire) were measured at baseline, 3-, 6-, 12-, and 24-month follow-up. Associations between psychological problems and care use/costs were investigated using logistic and multiple regression analyses. Results: Data of 558 patients were used. Distress, symptoms of anxiety or depression, FCR, and/or anxiety disorder at baseline were significantly associated with higher use of primary care, supportive care, and/or informal care (odds ratios (ORs) between 1.55 and 4.76). Symptoms of anxiety, FCR, and/or depression disorder at 12-month follow-up were significantly associated with use of primary care, supportive care, and/or informal care (ORs between 1.74 and 6.42). Distress, symptoms of anxiety, and FCR at baseline were associated with higher total costs. Discussion: HNC patients with psychological problems make more use of healthcare and informal care and have higher costs. This is not the result of worse clinical outcomes.  相似文献   
955.
ContextThe risk of contrast-induced acute kidney injury (CI-AKI) is increasing and the harm is great. Quercetin is the main active component in Abelmoschus manihot (L.) Medik (Malvaceae) and was reported to reduce the expression of HIF-1α.ObjectiveWe investigate whether quercetin improves the CI-AKI through the HIF-1α/lncRNA NEAT1/HMGB1 pathway.Materials and methodsHK-2 cells were treated with iohexol (200 mg/mL) for 6 h to establish a CI-AKI model. Quercetin (20 μM) was administered to CI-AKI cells cultured in dishes for 24 h. Cell morphology was observed by a fluorescence microscope. MTT and TUNEL assays were used to detect cell survival rate and apoptosis. Relative mRNA levels were measured by qRT-PCR. Protein levels were detected using western blotting. IL-6 and TNF-α protein levels were tested by Elisa assay. Targeting binding sites of HIF-1α and lncRNA NEAT1 were detected by luciferase assay.ResultsThe IC50 value of quercetin was 163.25 μM. The expression levels of HIF-1α, lncRNA NEAT1 and HMGB1 were upregulated in the CI-AKI cell model. Quercetin diminished cell injury and apoptosis via inhibiting HIF-1α. Silencing of HIF-1α targeting lncRNA MEAT1 diminished cell injury and apoptosis. Silencing lncRNA NEAT1 has the same effect via suppressing HMGB1 expression. Collectively, quercetin diminished cell injury and apoptosis in CI-AKI cell model via the inhibition of HIF-1α on lncRNA NEAT1/HMGB1 signalling pathway.Discussion and conclusionsQuercetin diminished cell injury and apoptosis in CI-AKI cell mode via the inhibition of HIF-1α on the lncRNA NEAT1/HMGB1 signalling pathway, offering a potential novel therapeutic target for CI-AKI therapy.  相似文献   
956.
AimThis study aimed to synthesize qualitative evidence on experiences of patients with atrial fibrillation (AF) during the course of diagnosis and treatment. We addressed three main questions: (a) What were the experiences of patients with AF during the course of diagnosis and treatment? (b) How did they respond to and cope with the disease? (c) What were the requirements during disease management?DesignIn this study, qualitative evidence synthesis was performed using the Thomas and Harden method.Data SourcesElectronic databases, including PubMed, the Cochrane Library, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, the China Biomedical Database, the WanFang Database, Chinese National Knowledge Infrastructure and VIP, were searched. The databases were searched from inception to August 2021.Review MethodsTwo researchers independently selected studies using qualitative assessment and review instruments for quality evaluation and thematic synthesis for the data analysis.ResultsA total of 2627 studies were identified in the initial search and 15 studies were included. Five analytical themes were generated: ‘Diagnosing AF’; ‘The impact of AF on the patients’; ‘Self‐reorientation in the therapeutic process’; ‘Living with AF and QoL’; and ‘External support to facilitate coping strategies.’ConclusionsOur findings point out unique experiences of patients across the trajectory of AF related to delayed diagnosis, feelings of nonsupport, disappointment of repeated treatment failure and multiple distress associated with unpredictable symptoms. Future research and clinical practice are expected to improve the quality of medical diagnosis and treatment, optimize administrative strategy and provide diverse health support for patients with AF.ImpactUnderstanding the experiences and needs of patients with AF in the entire disease process will inform future clinical practice in AF integrated management, which would be helpful in improving the professionalism and confidence of healthcare providers. In addition, our findings have implications for improving the effectiveness of AF diagnostic and treatment services.Patient or Public ContributionThis paper presents a review of previous studies and did not involve patients or the public.  相似文献   
957.
122例非甲状腺来源的颈部囊性肿块临床分析   总被引:2,自引:0,他引:2  
目的:探讨各种非甲状腺来源的颈部囊性肿块的特点,提高颈部肿块术前诊断的准确性,降低手术的盲目性和风险。方法:回顾性分析1999~2005年收治的非甲状腺来源的颈部囊性肿块122例。结果:资料表明,非甲状腺来源的颈部囊性肿块以先天性来源肿块最为多见,共84例,其中最常见的是甲状舌管囊肿;其次是感染性肿块30例,其中颌下腺囊肿25例;肿瘤来源最少见,共8例。主要根据肿块发生时间的长短,肿块的位置,颈部囊性肿块特异性表现和辅助检查来进行术前诊断。发现肿块的位置没有特殊性。根据某些肿块特征性的体征和穿刺检查,可明确诊断。结论:对非甲状腺来源的颈部囊性肿块,术前尽可能的明确诊断能有效地减少手术盲目性,降低手术并发症。  相似文献   
958.
Early initiation of breastfeeding, within 1 h of birth, is vital for the health of newborns and reduces morbidity and mortality. Secondary analysis of the 2016 Nepal Demographic and Health Survey (DHS) showed that early initiation of breastfeeding significantly reduced the risk of acute respiratory infection (ARI) in children under 2 years. Early initiation of breastfeeding requires maternal proximity. Separation of infant and mother inhibits early initiation of breastfeeding and increases the risk that infants will suffer from ARIs. However, during the COVID‐19 pandemic, guidance varied, with some recommending that infants and mothers with SARS‐CoV‐2 be isolated from one another. Nepal''s Ministry of Health and Population recommended nonseparation, but the adherence to this guidance was inconsistent. Maternal proximity, nonseparation and early initiation of breastfeeding should be promoted in all birthing facilities.  相似文献   
959.
960.
目的:探讨多种方法综合治疗口腔及面颈部大面积静脉畸形的临床效果。方法:根据患者的年龄、病变部位、病变大小制订个体化治疗方案,采用多种药物联合注射,结合病变周围环形缝扎、激光、手术等方法综合治疗口腔颌面部大面积静脉畸形134例。结果:134例中治疗效果优79例(58.96%),良45例(33.58%),显效10例(7.46%),差0例。结论:采用多种方法综合治疗口腔颌面部大面积静脉畸形,对提高疗效、改善面部形态、维持局部功能、减少不良反应具有重要意义。  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