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   6785篇
  免费   232篇
  国内免费   149篇
耳鼻咽喉   55篇
儿科学   144篇
妇产科学   81篇
基础医学   883篇
口腔科学   68篇
临床医学   700篇
内科学   1025篇
皮肤病学   59篇
神经病学   389篇
特种医学   98篇
外科学   524篇
综合类   886篇
预防医学   370篇
眼科学   15篇
药学   1470篇
  3篇
中国医学   162篇
肿瘤学   234篇
  2023年   47篇
  2022年   95篇
  2021年   168篇
  2020年   157篇
  2019年   105篇
  2018年   110篇
  2017年   129篇
  2016年   148篇
  2015年   173篇
  2014年   369篇
  2013年   379篇
  2012年   375篇
  2011年   403篇
  2010年   318篇
  2009年   330篇
  2008年   357篇
  2007年   316篇
  2006年   271篇
  2005年   229篇
  2004年   191篇
  2003年   167篇
  2002年   130篇
  2001年   119篇
  2000年   115篇
  1999年   119篇
  1998年   91篇
  1997年   109篇
  1996年   92篇
  1995年   94篇
  1994年   82篇
  1993年   53篇
  1992年   77篇
  1991年   57篇
  1990年   68篇
  1989年   72篇
  1988年   75篇
  1987年   75篇
  1986年   68篇
  1985年   103篇
  1984年   93篇
  1983年   55篇
  1982年   99篇
  1981年   73篇
  1980年   56篇
  1979年   54篇
  1978年   41篇
  1977年   44篇
  1976年   52篇
  1975年   33篇
  1973年   39篇
排序方式: 共有7166条查询结果,搜索用时 93 毫秒
1.
Background: Considering the poor prognosis of non-small cell lung cancer (NSCLC), the objective of this study was to examine the potential of plasma-derived vesicles as a source of lung cancer-specific proteins. Extracellular vesicle (EV) cargos are specific to the source cells, hence they have the potential of being a source of cancer-specific proteins.  Methods: The proteins differently expressed in cancer were determined and derived from EVs isolated from the plasma of NSCLC patients at the National Lung Hospital. To this end, purification was done using gel filtration chromatography and ultracentrifugation. In addition, nano liquid chromatography mass spectrometry (LC–MS/MS) was used for analyzing. Results: Fifty-seven EV-derived proteins related to NSCLC were highlighted in this research. Some of them have not been addressed before, such as EEF1A1 (elongation factor 1-α1), KPNB1 (Importin subunit beta 1), SRC (proto-oncogene tyrosine-protein kinase) and ACTC1 (actin, alpha cardiac muscle 1). This list was further confirmed through a comparison with ExoCarta and Vesiclepedia. Conclusion: This study is the first work to show the involvement of several novel proteins of small EV (EEF1A1, KPNB1, SRC, and ACTC1) in the progression of NSCLC. The results suggested that they could serve as novel biomarkers for non-small cell lung cancer in the future.  相似文献   
2.
AimTo determine whether convalescent angiotensin (1?7) peptide replacement therapy with plasma (peptide plasma) transfusion can be beneficial in the treatment of critically ill patients with severe coronavirus 2 (SARS-CoV-2) infection.Study designCase series of 9 critically ill patients with laboratory-confirmed COVID-19 who met the following criteria: severe pneumonia with rapid progression and continuously high viral load despite antiviral treatment.Peptide plasma: Plasma with angiotensin (1?7) content 8–10 times higher than healthy plasma donors was obtained from suitable donors. Peptide plasma transfusion was applied to 9 patients whose clinical status and/or laboratory profile deteriorated and who needed intensive care for 2 days.ResultsIn our COVID-19 cases, favipiravir, low molecular weight heparin treatment, which is included in the treatment protocol of the ministry of health, was started. Nine patients with oxygen saturation of 93% and below despite nasal oxygen support, whose clinical and/or laboratory deteriorated, were identified. The youngest of the cases was 36 years old, and the oldest patient was 85 years old. 6 of the 9 cases had male gender. 3 cases had been smoking for more than 10 years. 4 cases had at least one chronic disease.In all of our cases, SARS CoV2 lung involvement was bilateral and peptide plasma therapy was administered in cases when oxygen saturation was 93% and below despite nasal oxygen support of 5 liters/minute and above, and intensive care was required. Although it was not reflected in the laboratory parameters in the early period, 8 patients whose saturations improved with treatment were discharged without the need for intensive care. However, a similar response was not obtained in one case. Oxygen requirement increased gradually and, he died in intensive care process. An increase of the platelet count was observed in all cases following the peptide plasma treatment.ConclusionIn this preliminary case series of 9 critically ill patients with COVID-19, administration of plasma containing angiotensin (1?7) was followed by improvement in their clinical status. The limited sample size and study design preclude a definitive statement about the potential effectiveness of this treatment, and these observations require evaluation in clinical trials.  相似文献   
3.
目的观察病毒性心肌炎(VMC)病儿血浆外泌体微小RNA(miR)-148a的水平并分析其意义。方法选择2017年9月至2019年6月郑州大学附属儿童医院收治的VMC病儿112例纳入研究组,另选取同期门诊健康体检正常儿童112例为对照组,实时荧光定量PCR(RT-qPCR)检测血浆外泌体miR-148a水平,酶联免疫吸附测定(ELISA)检测血浆外泌体心肌肌钙蛋白I(cTnI),采用自动化生化仪检测血浆外泌体肌酸激酶同工酶(CK-MB)水平、超敏C反应蛋白(hs-CRP)水平。采用Pearson相关性分析检验VMC病儿血浆外泌体miR-148a与cTnI、CK-MB、hs-CRP水平的相关性。绘制受试者工作特征曲线(ROC)分析血浆外泌体miR-148a对VMC的诊断价值。结果血浆外泌体在透射电镜下呈大小不等、直径约100 nm典型圆形或椭圆形囊泡结构。与对照组比较,研究组血浆外泌体miR-148a水平[(1.01±0.12)比(5.34±1.06)]、血浆cTnI、CK-MB、hs-CRP水平均增加(均P<0.001)。VMC病儿血浆外泌体miR-148a与血浆cTnI、CK-MB、hs-CRP水平均呈正相关(r=0.62、0.64、0.49,均P<0.001)。血浆外泌体miR-148a及血浆cTnI、CK-MB、hs-CRP诊断早期VMC的曲线下面积(AUC)分别为0.94、0.94、0.83、0.86,截断值分别为1.87、0.19 μg/L、56.45 U/L、2.06 mg/L,灵敏度分别为94.60%、92.90%、84.80%、83.90%,特异度分别为92.90%、94.60%、83.90%、83.90%。血浆外泌体miR-148a与血浆cTnI诊断早期VMC的效能一致,均优于血浆CK-MB、hs-CRP。结论VMC病儿血浆外泌体miR-148a水平上调,可能对VMC有一定诊断价值。  相似文献   
4.
目的鼻内镜等离子辅助下鼻前庭囊肿切除与传统齿龈切口切除鼻前庭囊肿临床效果分析。方法回顾性的分析2015年03月-2019年01月在本院就诊90例鼻前庭囊肿患者,其中45例患者行鼻内镜低温等离子辅助下鼻前庭囊肿切除术(等离子组),45例患者行传统齿龈切口切除鼻前庭囊肿(齿龈组),(两种手术均经同一医生在相同条件下行手术治疗),对比两组的手术时间,术中出血,术后疼痛(采用疼痛VAS评分),术后感染复发等情况。结果等离子组较齿龈组手术时间短、出血量少,术后疼痛轻,恢复快。结论鼻内镜下低温等离子辅助治疗鼻前庭囊肿是治疗鼻前庭囊肿的有效术式,且优于传统术式。  相似文献   
5.
The aim of the study was to investigate the efficiency of ram seminal plasma and fetal calf serum on freezing of buck semen. Twenty ejaculates were collected using an electro-ejaculator and split into six groups. While FCS additive was not used in A1, A2 and A3 groups, 10% FCS was added to B1, B2 and B3 groups. These groups were then edited according to whether the buck or ram SP was involved. The design of the groups was done as follows: Group A1 (control 1), group A2 without buck SP, group A3 containing ram SP instead of buck SP. Groups B1 (control 2), B2 and B3 were the FCS added forms of these groups. Progressive sperm motility percentages in Group A1 and Group B2 were found to be higher when compared to the lowest Group B3. There were no significant differences between the groups in neither the levels of reactive oxygen species nor the enzyme and glutathione activities. In conclusion, the lack of statistical difference between the groups suggested that despite the supplements used but only when the buck spermatozoa structure was healthy, the cell could preserve acrosome, DNA and the integrity of membrane.  相似文献   
6.
目的 探讨结外NK/T细胞淋巴瘤鼻型(ENKTL)患者治疗前B症状与血浆EBV‐DNA拷贝数和血清细胞因子水平的相关关系,并分析其机制和预后价值。方法 回顾性分析资料齐全的173例患者,其中男性116例,女性57例,中位年龄43岁(4~71岁)。Ann Arbor分期Ⅰ‐Ⅱ期126例,Ⅲ‐Ⅳ期47例。肿瘤原发部位包括鼻腔(100例)、非鼻腔上呼吸消化道(34例)和上呼吸消化道以外(39例)。治疗前有和无B症状者分别为91例和82例。按照血浆EBV‐DNA拷贝数的高低分为阴性组36例、低载量(<104 copies/ml)组73例和高载量(≥104 copies/ml)组64例。检测的血清细胞因子包括IFN‐γ、IL‐2、IL‐4、IL‐6、IL‐10和TNF‐α。相关性分析采用Cochran‐Armitage趋势检验和Spearman相关性分析,采用Cox回归风险模型进行单因素分析评估预后影响因素并用Kaplan‐Meier法绘制生存曲线。结果 B症状及发热的发生与血浆EBV‐DNA拷贝水平的增加呈显著一致的趋势,发生B症状的患者其血清IFN‐γ、IL‐6和IL‐10的水平均高于无B症状组(P均<0.001)。血清IFN‐γ、IL‐6和IL‐10水平也均与血浆EBV‐DNA拷贝数呈正相关。B症状的发生与ENKTL患者的高危临床特征相关,包括晚期、原发肿瘤局部侵犯、区域淋巴结累及和治疗前LDH升高。单因素生存分析显示,Ann Arbor分期、B症状、血浆EBV‐DNA及上述血清细胞因子均为OS和PFS的影响因素(P均<0.05)。然而,多因素分析并未显示B症状对生存的独立预后价值。结论 ENKTL患者B症状的发生与EBV‐DNA拷贝水平和细胞因子的增高有关,这些指标也是影响ENKTL患者预后的重要因素。  相似文献   
7.
【目的】观察日间连续性血液净化联合血浆置换对非胆源性重症急性胰腺炎(SAP)患者炎症因子及肠黏膜屏障功能障碍的影响。【方法】本院收治的80例非胆源性SAP患者随机分为两组,各40例。血液净化组接受日间连续性血液净化治疗,联合组在血液净化组基础上接受至少1次的血浆置换治疗。比较两组治疗效果、炎症指标、肠黏膜屏障功能、并发症发生情况及死亡情况。【结果】联合组总有效率(87.5%)高于血液净化组(65.0%)(P<0.05)。治疗后,两组血淀粉酶及脂肪酶均较治疗前降低(均P<0.05),且联合组较血液净化组低(均P<0.05);两组CRP、TNF-α、降钙素原均较治疗前降低(均P<0.05),且联合组较血液净化组低(均P<0.05);两组内毒素、二胺氧化酶、D-乳酸均较治疗前降低(均P<0.05),且联合组较血液净化组低(均P<0.05)。联合组治疗期间新发总并发症发生率低于血液净化组(20.0%vs 35.0%),但差异无显著性(P>0.05),两组病死率(5.0%vs 7.5%)比较差异无显著性(P>0.05)。【结论】相比单独使用日间连续性血液净化,联合血浆置换可提高非胆源性SAP的疗效,改善患者胃肠功能及炎症水平,且安全性高。  相似文献   
8.
Hypertrophic burn scars remain a significant burden for patients and a challenge for clinicians.The aimAssessement of the efficacy of combined Pulsed Dye Laser and Ablative Fractional CO2 Laser therapy on hyperthophic scars and correlation with plasma levels of MMP-2, TIMP-1 and alpha-1 type I collagen.Patients and methodsTwenty five pediatric subjects were enrolled into the study. Control group consisted of age-matched subjects admitted for surgical repair of inguinal hernia. For the assessment of the results of laser treatment we used the Vancouver scar scale (VSS), and Patient-Observer Scar Assessment Scale (POSAS). We also correlated clinical results with plasma levels of MMP-2, TIMP-1 and alpha-1 type I collagen.ResultsAll subjects reported the laser treatment resulted in improvement and were somewhat satisfied or very satisfied with their experience. No adverse events were reported. The levels of MMP-2, TIMP-1 and alpha-1 type I collagen in our patients with scars before laser threatment were higher in comparison to controls. We also found statistically significant decrease in the levels of MMP-2, TIMP-1 and alpha-1 type I collagen after laser treatment of burn scarsConclusionsOur study clearly shows that combined CO2-AFL treatment for burn scars improve texture, colour, function and alleviate pruritus. We believe that decrease in the levels of MMP-2, TIMP-1 and alpha-1 type I collagen after laser treatment of burn scars, reflects reduced dynamic of scar.  相似文献   
9.
BackgroundThe treatment of cutaneous leishmaniasis is a challenge. A better understanding of the in situ mechanisms involved in the evolution and cure of the disease is essential for the development of new therapies.ObjectiveCorrelate histopathological and immunological characteristics of cutaneous leishmaniasis lesions with clinical outcome after different treatment regimens.MethodsThe authors analyzed cellular infiltration and immunohistochemistry staining for CD4, CD8 and IL-17 in biopsy samples from 33 patients with cutaneous leishmaniasis before treatment. All patients were recruited in a randomized clinical trial at Corte de Pedra (Bahia-Brazil) and assigned to receive Glucantime®, Glucantime® + Oral Tamoxifen or Glucantime® + Topical Tamoxifen. Patients were followed for 2 to 6 months to define disease outcome.ResultsA similar expression of CD4, CD8 and IL-17 was observed in lesion samples regardless of clinical outcome. In general, a higher amount of CD8 cells were observed compared with CD4 cells. An important observation was that all patients whose cellular infiltrate did not contain plasma cells were cured after treatment.Study limitationsIsolated quantification of TCD8 and IL-17 using immunohistochemistry is insufficient to analyze the role of these molecules in the immunopathogenesis of cutaneous leishmaniasis. In addition, the expansion of the immunohistochemistry panel would allow a more complete analysis of the immune response in situ.ConclusionsThe absence of plasma cells in cutaneous leishmaniasis lesions was related to a favorable therapeutic outcome.  相似文献   
10.
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