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   99981篇
  免费   7674篇
  国内免费   2629篇
耳鼻咽喉   407篇
儿科学   2942篇
妇产科学   1611篇
基础医学   8339篇
口腔科学   1354篇
临床医学   14100篇
内科学   17248篇
皮肤病学   747篇
神经病学   4580篇
特种医学   3576篇
外国民族医学   5篇
外科学   8064篇
综合类   17289篇
预防医学   8787篇
眼科学   995篇
药学   9132篇
  112篇
中国医学   8229篇
肿瘤学   2767篇
  2024年   96篇
  2023年   1747篇
  2022年   2401篇
  2021年   4315篇
  2020年   4310篇
  2019年   3574篇
  2018年   3404篇
  2017年   3385篇
  2016年   3294篇
  2015年   3292篇
  2014年   6539篇
  2013年   6750篇
  2012年   5707篇
  2011年   6135篇
  2010年   4859篇
  2009年   4499篇
  2008年   4474篇
  2007年   4699篇
  2006年   3984篇
  2005年   3638篇
  2004年   3165篇
  2003年   2857篇
  2002年   2382篇
  2001年   2296篇
  2000年   1809篇
  1999年   1588篇
  1998年   1366篇
  1997年   1441篇
  1996年   1160篇
  1995年   1201篇
  1994年   1154篇
  1993年   872篇
  1992年   883篇
  1991年   782篇
  1990年   603篇
  1989年   584篇
  1988年   549篇
  1987年   458篇
  1986年   428篇
  1985年   613篇
  1984年   516篇
  1983年   330篇
  1982年   462篇
  1981年   339篇
  1980年   299篇
  1979年   214篇
  1978年   189篇
  1977年   167篇
  1976年   155篇
  1975年   78篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
《Vaccine》2022,40(30):4038-4045
PurposeAs protection from COVID-19 following two doses of the BNT162b2 vaccine showed a time dependent waning, a third (booster) dose was administrated. This study aims to compare the antibody response following the third dose versus the second and to evaluate post-booster seroconversion.MethodsA prospective observational study conducted in Maccabi Healthcare Services. Serial SARS-CoV-2 Spike IgG tests, 1,2,3 and 6 months following the second vaccine dose and one month following the third were obtained. Neutralizing antibody levels were measured in a subset of participants. Per individual SARS-CoV-2 Spike IgG titer ratios were calculated one month after the booster administration compared to titers one month following the second dose and prior to booster.ResultsAmong 110 participants, 56 (51%) were women. Mean age was 61.7 ± 1.9 years and 66 (60%) were immunocompromised. One month after third dose, IgG titers were induced 7.83 (95 %CI 5.25–11.67) folds and 2.40 (95 %CI 1.90–3.03) folds compared to one month after the second, in the immunocompromised and immunocompetent groups, respectively. Of the 17 immunocompromised participants who were seronegative after the second dose, 4 (24%) became seropositive following the third. Comparing the titers prior to the third dose, an increase of 50.7 (95 %CI 32.5–79.1) fold in the immunocompromised group and 25.7 (95 %CI 19.1–34.7) fold in and immunocompetent group, was observed.ConclusionA third BNT162b2 vaccine elicited robust humoral response, superior to the response observed following the second, among immunocompetent and immunocompromised individuals.  相似文献   
3.
周秀芳 《全科护理》2022,20(1):131-134
目的:探讨连续性血液净化治疗患儿静脉留置导管感染风险因素,据此构建风险预测体系,并检验其实际应用效果,以期为临床预防护理提供依据。方法:选取医院2018年4月—2020年4月收治的400例连续性血液净化治疗患儿,按两组基础资料具有匹配性原则将其分为构建组300例、验证组100例,统计构建组中静脉留置导管感染患儿例数,通过单因素分析、多因素Logistic回归分析筛选静脉留置导管感染的独立危险因素,据此构建风险预测体系,并检验其在验证组中的应用效果。结果:经统计得到,构建组中静脉留置导管感染患儿共66例,感染发生率为22.00%;单因素分析得到,连续性血液净化治疗患儿静脉留置导管感染风险因素有穿刺部位、导管留置时间、插管次数、血流速度、血红蛋白、遵医依从性、抗生素使用时间、操作人员手卫生(P<0.05);多因素Logistic回归分析得到,连续性血液净化治疗患儿静脉留置导管感染独立风险因素有股静脉置管、导管留置时间>7 d、血流速度>180 mL/min、血红蛋白<100 g/L、遵医依从性差、抗生素使用时间>7 d(P<0.05);构建得到连续性血液净化治疗患儿静脉留置导管感染风险预测体系为P=1/[1+e^(-(-1.935+1.635×股静脉置管+1.740×导管留置时间>7 d+1.725×血流速度>180 mL/min+2.241×血红蛋白<100 g/L+2.089×遵医依从性差+1.331×抗生素使用时间>7 d))],ROC曲线分析显示,曲线下面积AUC=0.881,灵敏度为86.67%,特异性为97.14%,准确率为94.00%。结论:连续性血液净化治疗患儿静脉留置导管感染风险大,且风险因素复杂,研究构建的静脉留置导管感染风险预测体系灵敏度高、特异性强,评估准确率高。  相似文献   
4.
This study investigated the role of dual-energy computed tomography (CT) for lesion characterization in patients with peripheral arterial disease manifesting with chronic total occlusions (CTOs). Forty-one symptomatic patients with CTOs underwent dual-energy CT angiography before endovascular treatment. The lesions were subsequently analyzed in a dedicated workstation, and 2 indexes—dual-energy index (DEI) and effective Z (Zeff)—were calculated, ranging from 0.0027 to 0.321 and from 6.89 to 13.02, respectively. Statistical analysis showed a significant correlation between the DEI and Zeff values (P < .001). The interobserver intraclass correlation coefficient was 0.91 for the mean Zeff values and 0.86 for the mean DEI values. This technique could potentially provide useful information regarding the composition of a CTO.  相似文献   
5.
ObjectivesRecurrent Aphthous Stomatitis (RAS) a chronic idiopathic oral mucosal disease. But yet the etiology and pathogenesis of RAS are not exactly known, it is thought that inflammation play an important role in the pathogenesis. The aim of this study is to demonstrate the role of systemic inflammation among the possible etiological factors of RAS and to find the possible diagnostic correlation between Systemic Immune Inflammation Index (SII).MethodsPatients who were consulted the otolaryngology outpatient clinic and diagnosed with RAS between 2019–2021 were retrospectively analyzed. Neutrophil/Lymphocyte Ratio (NLR), Platelet/Lymphocyte Ratio (PLR) and SII values were calculated based on the results of complete blood count. Demographic and hematological parameters between control and RAS groups were compared. The statistical significance level was considered as <0.05.ResultsThere was no statistically significant difference between the control and RAS groups in terms of sex and age distributions (p = 0.566 and p = 0.173, respectively). SII, NLR and PLR values were significantly higher in the RAS group compared to the controls (p < 0.001, p < 0.001 and p = 0.001, respectively). A very strong correlation between SII and NLR, moderately strong correlation between SII and PLR and moderate correlation between NLR and PLR values were detected (respectively ρ: 0.813, 0.719, 0.532; p-values <0.001).ConclusionSII, NLR and PLR has significantly higher levels in the RAS group compared to the control group, that it supports the role of systemic inflammation in the etiopathogenesis of RAS. In addition, the results show that SII is a valuable marker for inflammation.Level of evidence4.  相似文献   
6.
7.
ObjectivesOur aim was to evaluate the effect of the updated European Organization for Research and Treatment of Cancer (EORTC) and Mycoses Study Group 2019 definitions for invasive pulmonary aspergillosis (IPA) on patient classification and the related all-cause 12-week mortality.MethodsIn this retrospective cohort study from our tertiary care centre, we reclassified patients with haematological malignancy who underwent bronchoalveolar lavage between 2014 and 2019 for suspected IPA using the novel EORTC 2019 criteria. We performed receiver operating characteristic curve analysis to define the optimal cut-off for positive PCR and galactomannan and present survival analyses and their possible association with these diagnostic criteria through post hoc comparisons with log rank and Cox regression.ResultsFrom 323 episodes of suspected IPA in 282 patients, 73 were reclassified: 31 (42.5%) from possible to probable IPA, 5 (6.8%) from EORTC criteria not met to probable IPA, and 37 (50.7%) from EORTC criteria not met to possible IPA. Probable IPA increased therefore 11.1% (64/323, 19.8% to 100/323, 30.9%), mostly due to positive PCR (31/36, 86.1%). There was no difference in mortality between newly defined possible and probable IPA (log rank p = 0.950). Mortality was higher in probable cases with lower cycle thresholds (Ct values) versus higher Ct values (p = 0.004). Receiver operating characteristic curve analysis showed an optimal Ct value cut-off of 36.8 with a sensitivity of 75% (95% CI 64.9%–85.1%) and a specificity of 61.7% (95% CI 53.5–69.9) for 12-week mortality.DiscussionThe new EORTC criteria led to 11.1% more probable IPA diagnoses, mostly due to Aspergillus PCR. Restricting positive PCR to below a certain threshold might improve the discrimination of the new EORTC IPA categories for mortality.  相似文献   
8.
《Pancreatology》2022,22(2):270-276
Backgroundand purpose: Zinc is an essential element for human health and plays an important role in metabolic, immunological and other biological processes. The present study was conducted to investigate the association between zinc deficiency (ZD) and the perioperative clinical course in patients with pancreatic ductal adenocarcinoma (PDAC).MethodsOf 216 patients with PDAC who underwent elective pancreatectomy between 2013 and 2017 at our institution, 206 patients with sufficient clinical data were retrospectively reviewed. The perioperative variables were compared and the risk factors associated with infectious complications were identified.ResultsZD was preoperatively present in 36 (17.5%) of 206 patients with PDAC. In the patients of the ZD group, a higher proportion of males, higher preoperative modified Glasgow prognostic scores, a higher neutrophil-to-lymphocyte ratio, and a higher occurrence of postoperative infectious complications after pancreatectomy were observed, compared to the non-ZD group. By a univariate analysis, three risk factors were significantly associated with infectious complications after pancreatectomy: ZD (vs non-ZD: p = 0.002), serum albumin <3.5 g/dl (vs ≥ 3.5 g/dl: p = 0.005), and the procedure of pancreaticoduodenectomy (vs others: p = 0.013). By multivariate logistic regression analysis, the occurrence of infectious complications was significantly associated with ZD (OR 3.430, 95%CI 1.570 to 7.490, p = 0.002) and the procedure of pancreaticoduodenectomy (OR 2.030, 95%CI 1.090 to 3.770, p = 0.025).ConclusionsThe current study newly demonstrated that ZD could serve as a preoperative predictor of infectious complications after pancreatectomies in the patients with PDAC.  相似文献   
9.
目的 观察超声引导下关节腔内注射重组人Ⅱ型肿瘤坏死因子受体-抗体融合蛋白(益赛普)治疗血友病性关节病(HA)的价值。方法 回顾性分析32例接受超声引导下穿刺关节腔注射益赛普的HA患者,对比观察治疗前及治疗后1个月血友病关节健康评分(HJHS)、视觉模拟评分(VAS),以及超声所示目标关节增生滑膜厚度、血流信号、Melchiorre及中国早期血友病性关节病超声检测(HEAD-US-C)评分,评估其治疗价值。结果 对32例均成功完成超声引导下穿刺关节腔及腔内注射益赛普,共对18例膝关节、7例肘关节及7例踝关节进行治疗。术后未出现感染、出血等并发症。治疗后1个月,目标关节HJHS、VAS、Melchiorre评分、HEAD-US-C评分及增生滑膜最大厚度、平均厚度、血流信号均低于治疗前(P均<0.01)。结论 超声引导下关节腔内注射益赛普治疗HA安全、有效。  相似文献   
10.
PurposeTo evaluate the midterm outcomes of percutaneous transluminal renal angioplasty (PTRA) for pediatric renovascular hypertension (RVH).Materials and MethodsThe clinical data of patients who underwent PTRA for RVH in the authors’ hospital from 2012 to 2019 were retrospectively analyzed. Postprocedural blood pressure, glomerular filtration rate (GFR) of the affected kidney, restenosis, and complications were closely monitored.ResultsPTRA was performed in a total of 30 children (20 boys and 10 girls), with a mean age of 7.3 years ± 0.7 (range, 40 days to 13.9 years) and a mean weight of 25.0 kg ± 2.3 (range, 3.4–53 kg). The median follow-up period was 26.5 months (range, 1 month to 7.5 years). Technical success was achieved in 26 (86.7%) of the 30 patients. Restenosis developed in 3 patients (10.0%). Only 1 patient underwent stent implantation, and the stent fractured 8 months later, requiring further intervention. There were no other complications. In terms of clinical benefit of blood pressure control after the initial PTRA procedure, 15 patients (50%) were cured and 7 patients (23.3%) showed improvement. There was no significant difference in the etiology, lesion location, and lesion length between patients with clinical benefit and failure (P = .06, P = .202, and P = .06, respectively). GFR of the affected kidney was significantly improved from 19.9 mL/min ± 11.2 to 38.1 mL/min ± 11.9 at the 6-month follow-up after PTRA (P < .001).ConclusionsThe overall results of PTRA for pediatric RVH caused by different etiologies are promising. PTRA not only provided a clinical benefit of blood pressure control in 73.3% of the patients but also significantly improved the function of the affected kidney.  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