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   33853篇
  免费   3011篇
  国内免费   902篇
耳鼻咽喉   620篇
儿科学   1040篇
妇产科学   378篇
基础医学   2488篇
口腔科学   386篇
临床医学   2787篇
内科学   4524篇
皮肤病学   913篇
神经病学   2279篇
特种医学   2797篇
外国民族医学   4篇
外科学   4356篇
综合类   4645篇
现状与发展   1篇
预防医学   2125篇
眼科学   1631篇
药学   3821篇
  20篇
中国医学   1585篇
肿瘤学   1366篇
  2024年   34篇
  2023年   353篇
  2022年   672篇
  2021年   1158篇
  2020年   990篇
  2019年   1187篇
  2018年   1260篇
  2017年   1210篇
  2016年   1140篇
  2015年   1077篇
  2014年   1709篇
  2013年   1901篇
  2012年   1714篇
  2011年   1746篇
  2010年   1396篇
  2009年   1144篇
  2008年   1422篇
  2007年   1374篇
  2006年   1198篇
  2005年   901篇
  2004年   825篇
  2003年   901篇
  2002年   1620篇
  2001年   1946篇
  2000年   2098篇
  1999年   1374篇
  1998年   1255篇
  1997年   1144篇
  1996年   680篇
  1995年   416篇
  1994年   263篇
  1993年   189篇
  1992年   174篇
  1991年   142篇
  1990年   123篇
  1989年   111篇
  1988年   76篇
  1987年   87篇
  1986年   62篇
  1985年   134篇
  1984年   116篇
  1983年   109篇
  1982年   84篇
  1981年   69篇
  1980年   62篇
  1979年   34篇
  1978年   23篇
  1977年   21篇
  1976年   14篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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   
12.
13.
目的 分析南京市某国际高中学生艾滋病知识知晓率及其影响因素,为制定高中生艾滋病健康教育策略提供依据。方法 对南京市某国际高中所有学生开展纸质问卷调查,统计分析艾滋病知识知晓率及其影响因素。 共纳入171名高中生为调查对象,艾滋病和梅毒的知识知晓率分别为56.1%和46.8%;有过性行为的占14.6%,其艾滋病知识知晓率最高为32.0%,(χ2=10.799,P=0.005);有吸毒史的学生占9.3%,其艾滋病知识知晓率最高为31.2%,(χ2=21.062,P<0.001);梅毒知识知晓者与不知晓者的艾滋病知识知晓率差异具有统计学意义(χ2=21.716,P<0.001)。 该国际高中学生性病和艾滋病知识知晓率较低,对高中生开展毒品危害教育和性病艾滋病防治应作为健康教育工作重点。  相似文献   
14.
ObjectiveTo investigate the feasibility of transnasal heated humidified high flow nasal cannula oxygen therapy (HFNC) in the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with respiratory failure in elderly patients. MethodsA total of 176 elderly patients with AECOPD complicated with respiratory failure who were hospitalized at Peking University Shougang Hospital from December 2016 to January 2022 were enrolled, including 82 patients in an HFNC group and 94 patients in an NPPV group. After treatment, pulse oxygen saturation (SPO2), arterial partial pressure of carbon dioxide (PaCO2), oxygenation index (OI), respiratory rate (RR), heart rate (HR), mean arterial pressure (MAP), comfort score, discharge rate, rate of endotracheal intubation, rate of transfer to intensive care unit (ICU), and mortality were compared between the two groups. The independent sample t-test was used for comparison between the two groups. Statistical data are expressed in percentage or number of cases and the χ2 test was used for their comparisons. ResultsThe SPO2 values at 30 min, 1 h, and 6 h were significantly higher in the HFNC group than in the NPPV group (t=-2.049,-2.618, and -3.314, P=0.043, 0.010, and 0.001, respectively). SPO2 before discharge was significantly lower than that of the NPPV group (t=2.162, P=0.033), but OI at each time point and before discharge had no statistical significance (P>0.05). MAP at 6 h was significantly higher in the HFNC group than in the NPPV group (t=-2.209, P=0.029), but within the normal range. HRs at 2 h and 3 h in the HFNC group were significantly higher than those of the NPPV group (t=-2.199 and -2.336, P=0.030 and 0.021, respectively). There were no significant differences in RR, HR, or MAP between the two groups at other time points and before discharge (P>0.05). There was no significant difference in PaCO2 between the two groups (P>0.05). Comfort score in the HFNC group was significantly higher than that of the NPPV group (t=-46.807, P<0.001). There were no significant differences in discharge rate, ICU transfer rate, endotracheal intubation rate, and mortality between the two groups (P>0.05). ConclusionHFNC is as effective as NPPV in treating elderly patients with AECOPD complicated with type Ⅰ or mild type Ⅱ respiratory failure, and HFNC is more comfortable than NPPV.  相似文献   
15.
《Clinical lung cancer》2022,23(2):122-134
Introduction: Both pembrolizumab (P) as a monotherapy or in combination with platinum-based chemotherapy (PCT) represent standard first-line treatment options for advanced non-small cell lung cancer (aNSCLC) with PD-L1 tumor proportion score (TPS)≥50%. No predictive biomarkers exist to guide treatment decisions.Methods: 423 consecutive patients with EGFR/ALK/ROS1-wild-type PD-L1 TPS≥50% aNSCLC receiving P (n = 302) or PCT (n = 121) as a first-line treatment were identified in the electronic databases of 5 Israeli cancer centers. Overall survival (OS, months [mo]) was assessed in correlation with blood biomarkers (BB: NLR, dNLR, PLR, SII, LIPI, ALI); a predictive score was developed.Results: In the propensity score matching analysis (n = 236; 118 patients in each group matched for age, sex and ECOG PS), mOS was 17.2mo (95% CI, 13.2-36.5) and 21.3mo (95% CI, 14.8-NR) in groups P and PCT, respectively (P = .44). In group P, NLR, dNLR, PLR, LIPI, and ALI significantly correlated with OS in uni- and multivariate COX regression analyses (P < .05), whereas in group PCT, none of the BB demonstrated a significant correlation. A predictive score was developed (each parameter receiving one point): age≥65, female sex, never-smoking status, adenocarcinoma histology, dNLR≥3. In patients with predictive score 3-5, OS was significantly longer with PCT as compared to P: mOS NR (95% CI, 15.3-NR) and 8.7mo (95% CI, 5.8-13.7) (P = .0005), while OS didn't differ significantly in patients with predictive score 0-2 (P = .61).Conclusion: With the limitations of the retrospective analysis, the proposed dNLR-based score appears to predict OS with P and PCT.  相似文献   
16.
Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin with antioxidant and anti-inflammatory properties. In this study, we explored the role and action mechanism of C3G in high glucose (HG)-induced damage of human nucleus pulposus cells (HNPCs). Cell viability was assessed by CCK-8 assay. TUNEL assay was performed for detecting apoptotic rate. Western blot was performed to determine the expression levels of cl-caspase-3, caspase-3, Bax, Bim, collagen II, aggrecan, MMP-3, MMP-13, and ADAMTS5. Reactive oxygen species (ROS) generation was analyzed using DCFH-DA staining. The Nrf2 was knocked down or overexpressed in HNPCs through transfection with si-Nrf2 or pcDNA3.0-Nrf2. C3G treatment (12.5, 25, and 50 μM) improved cell viability of HNPCs under HG condition. HG-induced cell apoptosis of HNPCs was attenuated by C3G with decreased apoptotic rate and relative levels of cl-caspase-3/caspase-3, Bax, and Bim. C3G treatment caused significant increase in expression levels of collagen II and aggrecan and decrease in the relative levels of MMP-3, MMP-13, and ADAMTS5. After treatment with C3G, ROS generation in HNPCs was markedly reduced. Treatment with N-acetylcysteine (NAC) reversed HG-induced cell apoptosis and extracellular matrix (ECM) degradation. C3G treatment induced the expression of Nrf2 and HO-1 in HG-induced HNPCs. Moreover, knockdown of Nrf2 reversed the inhibitory effect of C3G on ROS production. Summarily, C3G exerted a protective effect on ROS-mediated cellular damage in HNPCs under HG condition, which was attributed to the induction of the Nrf2/HO-1 signaling pathway.  相似文献   
17.
18.
ObjectiveWith this case report, we would like to highlight the importance of a multidisciplinary approach and atypical findings of congenital high airway obstruction sequence (CHAOS), anhydramnios, and renal dysgenesis in the prenatal diagnosis of Fraser syndrome (FS).Case reportA 25-year-old primigravida at 19 weeks of routine anomaly scan revealed abnormal sonographic findings such as fetal bilateral dysplastic small kidneys and gross oligohydramnios. The further detailed evaluation revealed that both fetal lungs were hyperechogenic with prominent (dilated) trachea and bronchi suggestive of CHAOS. Based on these findings, a diagnosis of FS was suspected. The couple was counseled and the pregnancy was terminated. The postmortem evaluation and novel homozygous variant in the FRAS1 gene confirmed the diagnosis of FS.ConclusionThe diagnosis and counseling of the patient were supported by a well-coordinated, multidisciplinary approach involving an obstetrician, a fetal medicine specialist, a medical geneticist, and a fetal pathologist.  相似文献   
19.
The ichroma? IGRA-TB (Boditech Med Inc., Chuncheon, Republic of Korea) is an automated fluorescent immunoassay-based point-of-care interferon-gamma release assay for detecting latent tuberculosis infection. We evaluated this assay with 408 health care workers, and demonstrated its acceptable performances comparing to QuantiFERON-TB Gold-Plus (QFT-Plus; Qiagen, Germantown, MD).  相似文献   
20.
1文献来源Jabbour SK,Lee KH,Frost N,et al.Pembrolizumab plus concurrent chemoradiation therapy in patients with unresectable,locally advanced,stageⅢnon?small cell lung cancer.The phase 2 KEYNOTE?799 nonrandomized trial[J].JAMA Oncol,2021,7(9):1-9.  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