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   62595篇
  免费   4404篇
  国内免费   1449篇
耳鼻咽喉   169篇
儿科学   1437篇
妇产科学   774篇
基础医学   4577篇
口腔科学   547篇
临床医学   7748篇
内科学   19741篇
皮肤病学   297篇
神经病学   1028篇
特种医学   941篇
外国民族医学   1篇
外科学   7382篇
综合类   9799篇
现状与发展   3篇
预防医学   3349篇
眼科学   146篇
药学   5688篇
  53篇
中国医学   3198篇
肿瘤学   1570篇
  2024年   120篇
  2023年   1118篇
  2022年   1979篇
  2021年   2839篇
  2020年   2724篇
  2019年   2249篇
  2018年   2152篇
  2017年   2138篇
  2016年   2144篇
  2015年   2300篇
  2014年   4470篇
  2013年   4590篇
  2012年   3523篇
  2011年   4171篇
  2010年   3153篇
  2009年   3100篇
  2008年   3026篇
  2007年   3090篇
  2006年   2784篇
  2005年   2506篇
  2004年   1937篇
  2003年   1703篇
  2002年   1386篇
  2001年   1292篇
  2000年   958篇
  1999年   855篇
  1998年   684篇
  1997年   637篇
  1996年   604篇
  1995年   519篇
  1994年   532篇
  1993年   370篇
  1992年   330篇
  1991年   327篇
  1990年   283篇
  1989年   288篇
  1988年   273篇
  1987年   193篇
  1986年   168篇
  1985年   170篇
  1984年   151篇
  1983年   79篇
  1982年   103篇
  1981年   86篇
  1980年   73篇
  1979年   72篇
  1978年   52篇
  1977年   40篇
  1976年   43篇
  1974年   17篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
61.
《Vaccine》2020,38(39):6141-6152
Influenza vaccination is considered the most valuable means to prevent and control seasonal influenza infections, which causes various clinical symptoms, ranging from mild cough and fever to even death. Among various influenza vaccine types, the inactivated subunit type is known to provide improved safety with reduced reactogenicity. However, there are some drawbacks associated with inactivated subunit type vaccines, with the main ones being its low immunogenicity and the induction of Th2-biased immune responses. In this study, we investigated the role of a single-stranded RNA (ssRNA) derived from the intergenic region in the internal ribosome entry site of the Cricket paralysis virus as an adjuvant rather than the universal vaccine for a seasonal inactivated subunit influenza vaccine. The ssRNA adjuvant stimulated not only well-balanced cellular (indicated by IgG2a, IFN-γ, IL-2, and TNF-α) and humoral (indicated by IgG1 and IL-4) immune responses but also a mucosal immune response (indicated by IgA), a key protector against respiratory virus infections. It also increases the HI titer, the surrogate marker of influenza vaccine efficacy. Furthermore, ssRNA adjuvant confers cross-protective immune responses against heterologous influenza virus infection while promoting enhanced viral clearance. Moreover, ssRNA adjuvant increases the number of memory CD4+ and CD8+ T cells, which can be expected to induce long-term immune responses. Therefore, this ssRNA-adjuvanted seasonal inactivated subunit influenza vaccine might be the best influenza vaccine generating robust humoral and cellular immune responses and conferring cross-protective and long-term immunity.  相似文献   
62.
Abstract Guillain-Barré syndrome (GBS) is a disease of the peripheral nervous system, which is caused by aberrant immune responses directed against some components of peripheral nerves. GBS is rarely accompanied by cardiovascular involvement. We describe a case of acute neuropathy complicated by sudden heart failure and left ventricular dysfunction which had a presumably neurogenic origin. Pathogenesis of acute heart failure is probably due to transitorial stunned myocardium and neurogenic cardiac injury. We show a rare case of transitorial and acute cardiac dysfunction by echocardiography and laboratory markers of heart failure.  相似文献   
63.
BACKGROUND: Major depression has been associated cross-sectionally with increased cell-mediated immune activation but causality has been difficult to establish. This study prospectively investigated the hypothesis that baseline level of immune activation predicts the development of depression during interferon-alpha (IFN-alpha) treatment. METHODS: Sixteen hepatitis C patients without psychiatric disorder underwent IFN-alpha treatment. Proinflammatory and anti-inflammatory cytokines were determined before starting treatment. Presence of a major depressive disorder (MDD) was assessed at baseline and several times during treatment. RESULTS: Baseline soluble interleukin-2 receptor (sIL-2r), interleukin-6 (IL-6), and interleukin-10 (IL-10) concentrations were significantly increased in the five subjects that developed MDD during treatment compared with those that did not, with standardized effect sizes of 1.08, 1.16, and 1.25, respectively, controlling for marijuana use, cigarette smoking, and baseline level of depressive symptoms. CONCLUSIONS: Results suggest that increased immune activation, rather than an epiphenomenon, is a causal risk factor for the development of MDD.  相似文献   
64.
目的 观察不同钙离子浓度的透析液对血液透析患者透析后血清钙离子水平及血压变化的影响,为肾功能衰竭血液透析患者的高钙血症及高血压的防治提供依据。方法 选择不同钙离子浓度的透析液,将维持性血液透析患者分为高钙组(1.75mmol/L)和低钙组(1.25mmol/L),比较患者每次透析前后脉搏、血压,同时抽查患者透析前后血钙及血肌酐浓度的变化。结果透析后两组患者血肌酐浓度均显著下降,透析前后差异均具有统计学意义(P〈0.01);高钙组患者透析后血钙较透析前升高,差异具有统计学意义(P〈0.01),而低钙组患者血钙比透析前略降低,差异无统计学意义(P〉0.05)。高钙组患者透析后较透析前收缩压、舒张压及平均动脉压都升高,差异均具有统计学意义(P〈0.05),而低钙组患者透析后较透析前收缩压、舒张压及平均动脉压都降低,差异均具有统计学意义(P〈0.05)。透析后两组血钙比较差异具有统计学意义(P〈0.01);透析后低钙组较高钙组患者的收缩压、舒张压及平均动脉压都降低,三者差异均具有统计学意义(P〈0.01)。结论透析液钙离子浓度与血液透析患者血清钙离子水平及血压呈正相关,低钙透析液透析有助于维持性血液透析患者高血压的控制。  相似文献   
65.
目的观察急性脑梗死患者血清CRP在发病中的作用及临床意义。方法采用免疫比浊法对60例急性脑梗死患者的血清CRP水平进行动态观察(病程第1.7及14天),并与45例健康人进行比较。结果急性脑梗死患者血清CRP从病程第1天即升高(P〈0.01),至第7天达高峰,以后降低;重型患者明显高于轻、中型患者。结论血清CRP可能在急性脑梗死的发生、发展中起一定作用,并与病情严重程度呈正相关。  相似文献   
66.
Pancreatic panniculitis is an uncommon condition that can occur in association with pancreatic disease. We present a case of pancreatic panniculitis in a female pancreas-kidney transplant recipient 5 months post-transplant. The patient was on standard immunosuppressive medications and had acute rejection of her renal allograft. The diagnosis of allograft pancreatitis and rejection presenting with pancreatic panniculitis was supported clinically, histopathologically and by laboratory and imaging data. This is the fourth case of pancreatic panniculitis occurring in a transplant recipient and the first in a simultaneous pancreas-kidney transplant recipient. It is also the first case associated with allograft rejection. Clinicians should be aware that pancreatic panniculitis may be a manifestation of underlying allograft pancreatic disease.  相似文献   
67.
补肾排毒合剂治疗慢性肾衰竭营养不良60例临床观察   总被引:1,自引:0,他引:1  
目的:观察补肾排毒合剂治疗慢性肾衰竭营养不良的疗效.方法:90例慢性肾衰竭营养不良患者随机分为治疗组60例和对照组30例,并设健康对照组30例.治疗组和对照组在综合治疗的基础上,治疗组加用补肾排毒合剂,对照组加用爱西特和百令胶囊.比较两组肾功能、营养状态和血浆瘦素、神经肽Y的变化.结果:治疗组治疗后BUN、Scr明显降低,与治疗前及对照组相比均有统计学差异(P<0.05).治疗组营养状态好转,与治疗前及对照组相比均有统计学差异(P<0.05).两组慢性肾衰竭营养不良患者治疗前Leptin、NPY水平均高于健康组(P<0.05),治疗后治疗组Leptin、NPY较治疗前下降,有统计学意义(P<0.05),但与对照组相比无统计学差异(P>0.05).结论:补肾排毒合剂治疗慢性肾衰竭营养不良疗效明显,可降低BUN、Scr,改善营养不良状态.  相似文献   
68.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
69.
目的比较伊贝沙坦与雷米普利对充血性心力衰竭(CHF)的临床疗效及安全性。方法72例CHF患者在常规治疗基础上随机分为2组。伊贝沙坦组(36例)口服伊贝沙坦150 mg.d-1;雷米普利组(36例)口服雷米普利2.5 mg.d-1。治疗前与治疗6 mo后分别用超声心动图测量左室射血分数(LVEF)、左室短轴缩短分数(LVFS)、每搏输出量(SV)、心排量(CO)、心脏指数(CI)评估心功能。结果治疗6 mo后,2组心功能较治疗前非常明显改善(P<0.01),2组之间比较差异无统计学意义(P>0.05)。结论伊贝沙坦与雷米普利治疗CHF均有效,且疗效相当。  相似文献   
70.
目的 研究天文潮汐对心脏病患者发生心衰的影响。方法 分析 118例心脏病患者发生心衰在各潮汐期的分布。结果 在强天文潮汐期内心脏病患者发生心衰显著多于其余时期 ,而且在朔、望期发生的人数多于上、下弦期。结论 护理人员要了解天文潮汐的变化规律 ,教育心脏病患者在强天文潮汐期内要保持情绪稳定 ,必要时在强天文潮汐期内可给予心脏病患者适量的镇静剂和安眠药。  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