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   4223篇
  免费   323篇
  国内免费   78篇
耳鼻咽喉   40篇
儿科学   80篇
妇产科学   62篇
基础医学   509篇
口腔科学   77篇
临床医学   414篇
内科学   745篇
皮肤病学   91篇
神经病学   339篇
特种医学   135篇
外科学   445篇
综合类   302篇
一般理论   1篇
预防医学   331篇
眼科学   264篇
药学   269篇
  2篇
中国医学   46篇
肿瘤学   472篇
  2024年   4篇
  2023年   36篇
  2022年   110篇
  2021年   168篇
  2020年   138篇
  2019年   115篇
  2018年   148篇
  2017年   102篇
  2016年   113篇
  2015年   172篇
  2014年   206篇
  2013年   204篇
  2012年   366篇
  2011年   415篇
  2010年   207篇
  2009年   153篇
  2008年   282篇
  2007年   274篇
  2006年   238篇
  2005年   216篇
  2004年   169篇
  2003年   158篇
  2002年   115篇
  2001年   68篇
  2000年   65篇
  1999年   44篇
  1998年   35篇
  1997年   13篇
  1996年   13篇
  1995年   15篇
  1994年   7篇
  1993年   10篇
  1992年   24篇
  1991年   23篇
  1990年   30篇
  1989年   17篇
  1988年   20篇
  1987年   19篇
  1986年   15篇
  1985年   17篇
  1984年   11篇
  1983年   9篇
  1982年   6篇
  1981年   7篇
  1977年   6篇
  1976年   5篇
  1973年   10篇
  1972年   4篇
  1970年   3篇
  1964年   4篇
排序方式: 共有4624条查询结果,搜索用时 24 毫秒
91.
目的:将黄芩苷和牛血清白蛋白(bovine serum albumin,BSA)载入壳聚糖温敏凝胶,构建双缓释体系,检测凝胶对药物的体外释放情况。方法:采用乳化缩聚法制备黄芩苷-明胶微球(gelatin microspheres,GMS);用不同配比的壳聚糖溶液和β-甘油磷酸钠(β-glycerophosphate,β-GP)溶液制备壳聚糖温敏凝胶,观察在37℃的成胶情况,选择最佳配比;在此基础上,将不同浓度的黄芩苷-GMS与BSA共混于壳聚糖凝胶溶液,测定载药后的成胶情况及黄芩苷和BSA的体外释放情况。结果:成功制备了黄芩苷-GMS,载药率5.62%,包封率72.05%;1.8%壳聚糖溶液与9%的β-GP混合10min后可获得状态良好的凝胶;加载两种药物后的凝胶溶液相转变时间未发生改变;30d时低浓度组累积释放了63.79%,两个较高浓度组分别释放了74.86%、77.63%。结论:壳聚糖温敏凝胶可以同时负载黄芩苷-GMS和BSA两种药物,在室温下呈溶液状态,37℃下经过10min可转变成半固体凝胶,在体外释药可达30d。黄芩苷和牛血清白蛋白双缓释制剂的制备和释药性能检测为牙周组织修复再生药物的研制提供了基础。  相似文献   
92.
Right ventricular (RV) failure (RVF) is the main cause of death in patients with pulmonary artery hypertension (PAH). Sildenafil, a phosphodiesterase type 5 inhibitor, was approved recently for treatment of PAH patients. However, the mechanisms underlying RV contractile malfunction and the benefits of sildenafil on RV function are not well understood. We aimed to investigate the following: (1) the ultrastructural and excitation-contraction coupling alterations underlying PAH-induced RVF; (2) whether the ultrastructural changes are reversible; and (3) the mechanisms underlying the therapeutic benefits of sildenafil in PAH-RVF. We used a single injection of monocrotaline in Wistar rats to induce pulmonary vascular proliferation, which led to PAH and RVF. RV myocytes displayed severe transverse (T)-tubule loss and disorganization, as well as blunted and dys-synchronous sarcoplasmic reticulum Ca(2+) release. Sildenafil prevented and reversed the monocrotaline-induced PAH and LV filling impairment. Early intervention with sildenafil prevented RV hypertrophy and the development of RVF, T-tubule remodeling, and Ca(2+) handling dysfunction. Although late treatment with sildenafil did not reverse RV hypertrophy in animals with established RVF, RV systolic function was improved. Furthermore, late intervention partially reversed both the impairment of myocyte T-tubule integrity and Ca(2+) handling protein and sarcoplasmic reticulum Ca(2+) release function in monocrotaline-treated rats. In conclusion, PAH-induced increase in RV afterload causes severe T-tubule remodeling and Ca(2+) handling dysfunction in RV myocytes, leading to RV contractile failure. Sildenafil prevents and partially reverses ultrastructural, molecular, and functional remodeling of failing RV myocytes. Reversal of pathological T-tubule remodeling, although incomplete, is achievable without the regression of RV hypertrophy.  相似文献   
93.
Biological treatments earn increasing significance in the treatment of rheumatoid arthritis (RA) but are associated with high incremental cost-effectiveness ratio compared to conventional antirheumatic treatments such as disease-modifying antirheumatic drugs. As the most important objective of medical technologies should be to increase life years and/or patients’ health-related quality of life (HRQoL), measuring QoL and utility in RA patients treated with biological therapies is crucial. The objective of this study is to compare the utility and QoL of patients treated with biological (n = 85) and non-biological (n = 168) antirheumatic drugs in Hungary in a cross-sectional non-interventional study. A measure of impairment (Disease Activity Score (DAS)-28), QoL measure (EuroQol five Dimension (EQ-5D) Visual Analogue Scale (VAS), Rheumatoid Arthritis Quality of Life (RAQoL)) and utility measures (indirect: EQ-5D index, direct: time trade-off (TTO)) were applied using an interview method. The Pearson correlation was used to assess the strength of the relationship of different measures in the total study group (n = 253). The EQ-5D index (biological treatment: 0.608, non-biological treatment: 0.483; P = 0.012) and DAS-28 (biological treatment: 3.8, non-biological treatment: 4.5; P = 0.003) showed statistically significant difference between the two subcohorts after adjusting data by age, gender and disease duration. Our results indicate that patients on biological treatment have lower disease activity and higher utility; however, it was not statistically significant in all cases. According to our knowledge, TTO was not used previously in Hungarian RA patients. Utility data concerning biological treatments are essential for cost-utility models in health technology assessment reports for public reimbursement.  相似文献   
94.
95.
96.
ObjectivesTo assess the role of the Val66Met polymorphism at the brain-derived neurotrophic factor (BDNF) gene on the performance of children and adolescents with bipolar disorder [juvenile bipolar disorder (JBD)] on the Wisconsin Card Sorting Test (WCST).MethodsChildren and adolescents were assessed by the K-SADS-PL and a clinical evaluation for BD and comorbid conditions. Manic and depressive symptoms were assessed with the Young Mania Rating Scale and the Children Depression Rating Scale – Reviewed. The Val66Met polymorphism at the BDNF was genotyped from a blood sample. Patients’ IQ and executive functions were assessed by a standard cognitive flexibility test (WCST).ResultsFifty-three subjects were included in the study. No significant difference was observed between the Val/Val and Val/Met+Met/Met groups on any WCST scores in the MANCOVA (F48,5 = .76; p = .59; Perseverative Errors, p = .66; Nonperseverative Errors, p = .58; Categories Completed, p = .34; Attempts to Reach First Category, p=.64; and Percentage of Conceptual Level Responses, p = .99).ConclusionsOur findings from this sample of children and adolescents with BD do not replicate results from studies of adults and suggest the existence of differences in the neurobiology of this disorder across the life cycle. Investigations of larger samples are necessary to confirm these data.  相似文献   
97.
98.
Aims: To determine the immediate and long‐term results of endoscopic drainage and necrosectomy for symptomatic pancreatic fluid collections. Methods: The data of 80 patients with symptomatic pancreatic fluid collections (mean diameter: 11.7 cm, range 3–20; pseudocysts: 24/80, abscess: 20/80, infected walled‐off necrosis: 36/80) referred for endoscopic management from October 1997 to March 2008 were analyzed retrospectively. Results: Endoscopic drainage techniques included endoscopic ultrasound (EUS)‐guided aspiration (2/80), EUS‐guided transenteric drainage (70/80) and non‐EUS‐guided drainage across a spontaneous transenteric fistula (8/80). Endoscopic necrosectomy was carried out in 49/80 (abscesses: 14/20; infected necrosis: 35/36). Procedural complications were bleeding (12/80), perforation (7/80), portal air embolism (1/80) and Ogilvie Syndrome (1/80). Initial technical success was achieved in 78/80 (97.5%) and clinical resolution of the collections was achieved endoscopically in 67/80 (83.8%), with surgery required in 13/80 (perforation: four; endoscopically inaccessible areas: two; inadequate drainage: seven). Within 6 months five patients required surgery due to recurrent fluid collections; over a mean follow up of 31 months, surgery was required in four more patients due to recurrent collections as a consequence of underlying pancreatic duct abnormalities that could not be treated endoscopically. The long‐term success of endoscopic treatment was 58/80 (72.5%). Conclusions: Endoscopic drainage of symptomatic pancreatic fluid collections is safe and effective, with excellent immediate and long‐term results. Endoscopic necrosectomy has a risk of serious complications. The underlying pancreatic duct abnormalities must be addressed to prevent recurrence of fluid collections.  相似文献   
99.
Background and Aim: Environmental factors such as food, lifestyle and prevalence of Helicobacter pylori infection are widely different in Asian countries compared with the West, and physiological functions and genetic factors of Asians may also be different from those of Westerners. Establishing an Asian consensus for functional dyspepsia is crucial in order to attract attention to such data from Asian countries, to articulate the experience and views of Asian experts, and to provide a relevant guide on management of functional dyspepsia for primary care physicians working in Asia. Methods: Consensus team members were selected from Asian experts and consensus development was carried out by using a modified Delphi method. Consensus teams collected published papers on functional dyspepsia especially from Asia and developed candidate consensus statements based on the generated clinical questions. At the first face‐to‐face meeting, each statement was reviewed and e‐mail voting was done twice. At the second face‐to‐face meeting, final voting on each statement was done using a keypad voting system. A grade of evidence and strength of recommendation were applied to each statement according to the method of the GRADE Working Group. Results: Twenty‐nine consensus statements were finalized, including seven for definition and diagnosis, five for epidemiology, nine for pathophysiology, and eight for management. Algorithms for diagnosis and management of functional dyspepsia were added. Conclusions: This consensus developed by Asian experts shows distinctive features of functional dyspepsia in Asia and will provide a guide to the diagnosis and management of functional dyspepsia for Asian primary care physicians.  相似文献   
100.
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