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   193471篇
  免费   18410篇
  国内免费   8390篇
耳鼻咽喉   2432篇
儿科学   4479篇
妇产科学   2075篇
基础医学   38955篇
口腔科学   5666篇
临床医学   14694篇
内科学   27173篇
皮肤病学   5064篇
神经病学   10592篇
特种医学   5910篇
外国民族医学   125篇
外科学   16349篇
综合类   28810篇
现状与发展   55篇
预防医学   5524篇
眼科学   3703篇
药学   14401篇
  32篇
中国医学   5913篇
肿瘤学   28319篇
  2024年   260篇
  2023年   2678篇
  2022年   3496篇
  2021年   6923篇
  2020年   6246篇
  2019年   6348篇
  2018年   6577篇
  2017年   6709篇
  2016年   6960篇
  2015年   7877篇
  2014年   11516篇
  2013年   12771篇
  2012年   10950篇
  2011年   12332篇
  2010年   10154篇
  2009年   9780篇
  2008年   10201篇
  2007年   10381篇
  2006年   9389篇
  2005年   8559篇
  2004年   7639篇
  2003年   6654篇
  2002年   5452篇
  2001年   4748篇
  2000年   3930篇
  1999年   3531篇
  1998年   3389篇
  1997年   3042篇
  1996年   2685篇
  1995年   2428篇
  1994年   2196篇
  1993年   1823篇
  1992年   1402篇
  1991年   1293篇
  1990年   1045篇
  1989年   970篇
  1988年   889篇
  1987年   702篇
  1986年   666篇
  1985年   969篇
  1984年   933篇
  1983年   647篇
  1982年   695篇
  1981年   555篇
  1980年   472篇
  1979年   390篇
  1978年   277篇
  1977年   214篇
  1976年   201篇
  1975年   101篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
71.
72.
This study aimed to compare the differences in characteristics and prognoses between Asian and white patients receiving immunotherapy for nonsmall cell lung cancer (NSCLC). We studied 390 patients who received atezolizumab as part of the POPLAR or OAK trial, and analyzed the differences in baseline characteristics, outcomes and genetic mutations in blood samples between Asian and white patients. Overall survival (OS) was longer in Asian compared to white patients (median OS: 18.7 vs. 11.1 months; p = 0.005). Race was identified as an independent prognostic factor for OS (Asian vs. white: hazard ratio 0.647, 95% confidence interval 0.447–0.936, p = 0.021), together with performance status, histology, baseline sum of the longest tumor diameters (BLSLD) and number of metastatic sites. The two groups also differed in terms of characteristics including smoking history, BLSLD, epidermal growth factor receptor (EGFR) mutation frequency, programmed death-ligand 1 expression and blood-based tumor-mutation burden. Blood mutations of STK11, EGFR, KEAP1, POLE, GRM3, ATM and STAG2 were associated with treatment response, and TP53, KEAP1, APC, RB1, CREBBP, EPHA5 and STAG2 mutations were associated with OS. The blood-based mutation profiles differentiated between Asian and white patients, especially in relation to EGFR (23.8 vs. 8.5%), TP53 (30.2 vs. 46.9%) and STK11 (1.6 vs. 12.3%) mutations (all p < 0.05). The different clinicopathological features and mutation profiles in Asian and white patients may explain the superior outcome following atezolizumab treatment in Asian patients with NSCLC. The results of this study have important implications for further studies on racial disparities in relation to immunotherapy.  相似文献   
73.
目的:研究PTPN6对前列腺癌细胞PC3的作用及其作用机制。方法:RT-PCR和Western blot实验检测前列腺癌组织和细胞以及癌旁组织和人前列腺上皮细胞中PTPN6的表达量;CCK-8和EDU染色实验检测PTPN6对前列腺癌细胞PC3增殖的影响;Western blot实验检测耐药相关蛋白P-gp和MRP-1的蛋白表达水平。结果:RT-PCR和Western blot结果显示,PTPN6在前列腺癌组织和细胞中的表达量显著低于癌旁组织和人前列腺上皮细胞中的表达量;过表达PTPN6显著抑制前列腺癌PC3细胞的增殖,并降低PC3细胞的耐药性;进一步的研究结果表明PTPN6可通过抑制SP1,并抑制p38 MAPK通路抑制PC3细胞的增殖和耐药。结论:PTPN6能够抑制前列腺癌细胞PC3的增殖和耐药,提高其化疗敏感性,作用机制是通过调控SP1/p38 MAPK信号通路来实现的,这一结果能够为临床上前列腺癌的诊断和治疗提供分子基础。  相似文献   
74.
目的:探讨超高CD34+采集的动员方案后序贯二次自体造血干细胞移植治疗难治性霍奇金淋巴瘤的疗效和安全性。方法:对1例经过多疗程一线、二线、新药、免疫等均难治的霍奇金淋巴瘤患者,予以IA+C方案化疗+G-CSF动员干细胞后采集出超高水平CD34+细胞,之后行自体造血干细胞移植,移植后获得完全缓解,再予序贯第二次自体造血干细胞移植进行巩固治疗。结果:总计输注单个核细胞数13.67×108/kg,CD34+细胞48.68×106/kg,第一次自体造血干细胞移植术后第7天造血功能恢复,复查全身PET-CT提示获得完全缓解,第二次自体造血干细胞移植术后第8天造血功能恢复,两次自体造血干细胞移植相关并发症均在可控范围内。结论:超高CD34+细胞采集的IA+C方案化疗+G-CSF动员可以让患者有机会进行多次自体造血干细胞移植,是临床动员的创新方案。对于难治性霍奇金淋巴瘤,序贯二次自体造血干细胞移植可达到更深层次缓解,且安全性较高,延长患者无疾病生存期及总生存期,为难治性霍奇金淋巴瘤治疗提供更多临床依据。  相似文献   
75.
In the United States, renal cell carcinoma (RCC) incidence and the prevalence of obesity, an established risk factor for RCC, have been increasing for several decades. RCC is more common among older individuals. We sought to quantify the contribution of excess adiposity to the rising incidence of RCC among individuals 60 years or older. National Institutes of Health-American Association of Retired Persons Diet and Health Study data (n = 453 859 participants, enrolled in 1995-1996, age at enrollment 50-71 years) were used to estimate multivariable-adjusted hazard ratios (HRs) for RCC across body mass index categories and HRs associated with smoking. Population attributable fractions (PAFs) were calculated using estimated HRs and annual overweight/obesity prevalence from the National Health Interview Survey (1985-2008). PAF estimates were combined with RCC incidence from Surveillance, Epidemiology and End Results-13 to calculate annual percent changes in RCC incidence attributable (and unrelated) to overweight/obesity. We found that between 1995 and 2018, among individuals aged 60 years and older, PAF for overweight/obesity increased from 18% to 29% for all RCCs. In comparison, the PAF for smoking declined from 12% to 9%. RCC incidence increased 1.8% per year (95% confidence interval [CI] 1.5%-2.1%) overall, while RCC incidence attributable to overweight/obesity increased 3.8% per year (95%CI 3.5%-4.2%) and RCC incidence unrelated to overweight/obesity increased 1.2% per year (95% CI 0.9%-1.4%). In conclusion, overweight/obesity appears to have contributed importantly to the rising incidence of RCC in the United States since the mid-1990s. Public health interventions focused on reducing overweight and obesity could help substantially in curbing this trend.  相似文献   
76.
BackgroundSurgical resection is recommended for patients with resectable acinar cell carcinoma (ACC). The aim of this study was to investigate the clinical characteristics and surgical outcomes of resectable ACC in comparison to pancreatic ductal adenocarcinoma (PDAC).MethodA retrospective analysis was performed on all patients who consecutively underwent radical resection with pathologically confirmed ACC and PDAC from December 2011 to December 2018. Clinicopathologic characteristics and follow-up information were analyzed. A 1:3 propensity score matching (PSM) method was used to minimize the bias between ACC and PDAC.ResultsA total of 26 patients with ACC and 1351 with PDAC were included. Compared to PDAC, ACC tended to be larger (4.5 vs. 3.0 cm; p < 0.001) and more frequently located in the pancreatic body/tail (61.5% vs. 36.6%, p = 0.009), with lower total bilirubin levels, lower neutrophil lymphocyte ratio (NLR) levels and lower carbohydrate antigen 19-9 (CA19-9) levels and carcinoembryonic antigen (CEA) levels. There was no difference in postoperative morbidities in patients with ACC and PDAC. The median OS and RFS were longer in ACC when compared to PDAC (OS: 43.5 mo vs. 19.0 mo, p = 0.004; RFS: 24.5 mo vs. 11.6 mo, p = 0.023). After the 1:3 PSM, ACC remained to be a better histological type for OS (p = 0.024), but had comparable RFS with PDAC (p = 0.164).ConclusionPatients with ACC after radical resection had better OS than that with PDAC. However, ACC is also an aggressive tumor with a similar trend of RFS with PDAC after the matching, necessitating the multidisciplinary treatment for resectable ACC disease.  相似文献   
77.
ObjectiveTo investigate the association between type 1 diabetes mellitus (T1D) and type 2 diabetes mellitus (T2D) with risk of sudden cardiac arrest (SCA).MethodsIn a prospective community-based study of SCA from February 1, 2002, through November 30, 2019, we ascertained 2771 cases age 18 years of age or older and matched them to 8313 controls based on geography, age, sex, and race/ethnicity. We used logistic regression to evaluate the independent association between diabetes, T1D, T2D, and SCA.ResultsPatients had a mean age of 64.5±15.9 years, were 33.3% female and 23.9% non-White race. Overall, 36.7% (n=1016) of cases and 23.8% (n=1981) of controls had diabetes. Among individuals with diabetes, the proportion of T1D was 6.5% (n=66) among cases and 2.0% among controls (n=40). Diabetes was associated with 1.5-times higher odds of SCA. Compared with those without diabetes, the odds ratio and 95% CI for SCA was 4.36 (95% CI, 2.81 to 6.75; P<.001) in T1D and 1.45 (95% CI, 1.30 to 1.63; P<.001) in T2D after multivariable adjustment. Among those with diabetes, the odds of having SCA were 2.41 times higher in T1D than in T2D (95% CI, 1.53 to 3.80; P<.001). Cases of SCA with T1D were more likely to have an unwitnessed arrest, less likely to receive resuscitation, and less likely to survive compared with those with T2D.ConclusionType 1 diabetes was more strongly associated with SCA compared with T2D and had less favorable outcomes following resuscitation. Diabetes type could influence the approach to risk stratification and prevention of SCA.  相似文献   
78.
皮肤鳞状细胞癌是具有发病率高、发展快、可转移、易误诊等特点的一种恶性肿瘤,对人类的健康造成威胁。随着中医的发展和现代医学实验研究技术的进步,中医药在皮肤鳞状细胞癌的现代研究方面也取得一定成果。目前临床上治疗鳞状细胞癌多采取手术及药物化疗等,因不良反应的存在,患者接受度低。中药具有多靶点、安全性高、不良反应少等优势,在治疗皮肤鳞状细胞癌中中医具有一定优势,本文将围绕中药单体、中药复方,以及针灸在治疗皮肤鳞状细胞癌的研究进展展开论述和思考。  相似文献   
79.
目的采用图像融合技术获得T2WI与T2WI-FS的融合图像,评估其在肛瘘及肛周结构显示中的优势。 方法2016年6月至2018年6月,前瞻性选择中山大学附属第一医院29例肛瘘患者进行肛管磁共振(MR)检查,采用图像融合技术获取T2WI与T2WI-FS的融合图像T2WI-Fusion,利用Fisher score算法计算瘘管及肛门括约肌的组织间分辨力Fisher值、脂肪与肛门括约肌间的Fisher值,评估融合图像中瘘管及肛周结构的显示情况。采用改进的双刺激连续质量量表(DSCQS)对T2WI-FS、T2WI、增强3D-VIBE和T2WI-Fusion序列图像进行主观图像质量评价。 结果29例患者均成功获得T2WI与T2WI-FS的融合图像T2WI-Fusion。T2WI-Fusion、T2WI瘘管与括约肌间Fisher均值分别为6.46、3.31,T2WI-Fusion图像对瘘管的显示优于T2WI序列图像(P<0.001)。T2WI-Fusion、T2WI-FS脂肪与括约肌间Fisher均值分别为10.61、2.45,T2WI-Fusion图像对括约肌的显示优于T2WI-FS序列图像(P<0.001)。T2WI-Fusion对瘘管与括约肌的图像质量评价总评分均高于T2WI-FS、T2WI、增强3D-VIBE序列(P<0.001)。 结论MRI图像融合技术同时具备T2WI及T2WI-FS的优势,无需增加扫描序列及扫描时间,且操作简单,花费时间短,显著提高病变及肛周解剖结构的对比度和图像质量。  相似文献   
80.
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