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   27751篇
  免费   2152篇
  国内免费   842篇
耳鼻咽喉   580篇
儿科学   1142篇
妇产科学   297篇
基础医学   1921篇
口腔科学   373篇
临床医学   2646篇
内科学   4836篇
皮肤病学   559篇
神经病学   417篇
特种医学   1456篇
外国民族医学   16篇
外科学   5619篇
综合类   4172篇
现状与发展   4篇
预防医学   708篇
眼科学   598篇
药学   1477篇
  19篇
中国医学   934篇
肿瘤学   2971篇
  2024年   19篇
  2023年   364篇
  2022年   510篇
  2021年   899篇
  2020年   950篇
  2019年   869篇
  2018年   836篇
  2017年   848篇
  2016年   1038篇
  2015年   972篇
  2014年   1681篇
  2013年   1674篇
  2012年   1436篇
  2011年   1701篇
  2010年   1413篇
  2009年   1371篇
  2008年   1364篇
  2007年   1435篇
  2006年   1331篇
  2005年   1173篇
  2004年   1019篇
  2003年   863篇
  2002年   808篇
  2001年   692篇
  2000年   599篇
  1999年   488篇
  1998年   413篇
  1997年   401篇
  1996年   370篇
  1995年   380篇
  1994年   322篇
  1993年   260篇
  1992年   259篇
  1991年   253篇
  1990年   224篇
  1989年   193篇
  1988年   178篇
  1987年   131篇
  1986年   129篇
  1985年   144篇
  1984年   140篇
  1983年   90篇
  1982年   97篇
  1981年   84篇
  1980年   86篇
  1979年   66篇
  1978年   44篇
  1977年   44篇
  1976年   36篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
目的:探究三结构域蛋白59(TRIM59)调控人皮肤黑色素瘤细胞SK-MEL-2增殖、细胞周期、凋亡及迁移侵袭的作用机制,及其与Bcl2相关转录因子1(BCLAF1)之间的关系。方法:qPCR和WB法检测人表皮黑色素细胞HEMn-LP、人皮肤黑色素瘤细胞SK-MEL-2、UACC903、A375及36例邢台市人民医院2019年2月至2021年7月收集的皮肤黑色素瘤组织中TRIM59的mRNA和蛋白表达,使用脂质体将si-con、si-TRIM59转染至SK-MEL-2细胞中,WB法检测干扰TRIM59表达对细胞中周期蛋白D1(CCND1)、细胞周期素依赖性激酶2(CDK2)、肿瘤抑制蛋白基因(TP53)和 BCLAF1 蛋白表达的影响,CCK-8法、流式细胞术、划痕愈合实验、Transwell实验检测对细胞的活性、凋亡、迁移和侵袭的影响,免疫共沉淀(Co-IP)实验检测对细胞中TRIM59蛋白与BCLAF1结合能力的影响。结果:与HEMn-LP细胞相比,SK-MEL-2、UACC903、A375细胞中TRIM59 mRNA和TRIM59、BCLAF1蛋白均呈高表达(均P<0.05),SK-MEL-2细胞中TRIM59表达水平最高。相较于si-con组和Normal组,沉默TRIM59后,SK-MEL-2细胞的活性显著降低,细胞周期阻滞于G2期,CCND1、CDK2的蛋白表达显著降低,TP53蛋白和细胞凋亡率均显著升高,划痕抑制率明显升高,迁移侵袭细胞数明显降低(均P<0.05)。免疫共沉淀实验结果显示,TRIM59与BCLAF1之间存在蛋白结合关系。TRIM59与 BCLAF1 在肿瘤组织中的表达呈显著的正相关(r=0.878,P<0.001)。结论:干扰TRIM59表达能够抑制人皮肤黑色素瘤SK-MEL-2细胞的增殖、迁移和侵袭而促进凋亡,抑制SK-MEL-2细胞的恶性生物学行为,其机制可能与TRIM59结合BCLAF1有关。  相似文献   
2.
3.
4.
BackgroundIn order to avoid excessive treatment of thyroid nodules in the clinic, it is necessary to find a simple and practical analysis method to comprehensively and accurately reflect benign or malignant thyroid nodules. This study aimed to construct and validate a comprehensive and reliable network-based predictive model using a variety of imaging and laboratory criteria for thyroid nodules to stratify the risk of malignancy prior to surgery.MethodsWe retrospectively analyzed data from patients who underwent surgical treatment for thyroid nodules at the Thyroid and Breast Diagnosis and Treatment Center of Weifang Hospital of Traditional Chinese Medicine between January 2018 and December 2020. Binary logical regression analysis was performed to predict whether nodules were malignant or benign. The developmental dataset included 457 patients (January 2018–December 2020). The validation set included separate data points (n = 225, January 2018–December 2020).ResultsIn this study, criteria that showed significant predictive value for malignant nodules included TI-RADS: 4b (p = 0.065); Bethesda IV, Bethesda V, Bethesda VI (P < 0.0001); BRAFV600E mutation (P < 0.0001); Calcitonin>5 pg/ml (p = 0.0037); and FNA-Tg>30 ng/ml (p = 0.0003). A 10-grade risk scoring system was developed. The risk of malignancy risk ranged from 2.06% to 100% and was positively associated with increasing risk grade. The areas under the receiver-operating characteristic curve of the development and validation sets were 0.972 and 0.946, respectively.ConclusionA simple, comprehensive and reliable web-based predictive model was designed using a variety of imaging and laboratory criteria to stratify thyroid nodules by probability of malignancy.  相似文献   
5.
6.
7.
ObjectiveThe objective of this study was to investigate the association between morphological variation and postsurgical pulmonary vein (PV) stenosis (PPVS) in patients with cardiac total anomalous pulmonary venous connection (TAPVC).MethodsThis single-center, retrospective study included 168 pediatric patients who underwent surgical repair of cardiac TAPVC from 2013 to 2019 (connection to the coronary sinus [CS], n = 136; connection directly to the right atrium [RA], n = 32). Three-dimensional computed tomography modeling and geometric analysis were performed to investigate the morphological features; their relevance to the PPVS was examined.ResultsThe connection type had no association with PPVS (CS type: 18% vs right atrial type: 19%; P = .89) but there was a higher incidence of PPVS in patients with a single PV orifice than > 1 orifice (P < .001). Confluence-to-total PV area ratio (hazard ratio, 4.78, 95% CI, 1.86-12.32; P = .001) and length of drainage route (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < .001) had a 4- and 1-fold increase in the risk for PPVS in the CS type after adjustment for age and preoperative pulmonary venous obstruction. In the right atrial type, those with anomalous PV return to the RA roof were more likely to develop PPVS than to the posterior wall of the RA (P < .001).ConclusionsThe number of inter-junction PV orifice correlated with PPVS development in cardiac TAPVC. The confluence-to-total PV ratio, length of drainage route, and anomalous PV return to the RA roof are important predictors for PPVS. Morphological subcategorization in this clinical setting can potentially assist in surgical decision-making.  相似文献   
8.
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   
9.
This commentary reviews top advances in hepatobiliary cancer research in 2021–2022, focusing on leveraging immunotherapeutics in combination with other therapies earlier in the disease course and targeted to patient's individualized biomarkers that may predict response or resistance to checkpoint inhibitors.  相似文献   
10.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  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