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   98015篇
  免费   7652篇
  国内免费   4013篇
耳鼻咽喉   2001篇
儿科学   488篇
妇产科学   2818篇
基础医学   6000篇
口腔科学   560篇
临床医学   10974篇
内科学   5678篇
皮肤病学   378篇
神经病学   698篇
特种医学   6520篇
外国民族医学   52篇
外科学   19721篇
综合类   16012篇
现状与发展   3篇
预防医学   3245篇
眼科学   241篇
药学   4656篇
  14篇
中国医学   495篇
肿瘤学   29126篇
  2024年   173篇
  2023年   967篇
  2022年   2273篇
  2021年   2907篇
  2020年   2748篇
  2019年   2334篇
  2018年   2364篇
  2017年   2700篇
  2016年   3310篇
  2015年   3043篇
  2014年   6160篇
  2013年   5364篇
  2012年   6391篇
  2011年   7023篇
  2010年   5939篇
  2009年   5990篇
  2008年   6003篇
  2007年   6353篇
  2006年   5775篇
  2005年   5340篇
  2004年   4226篇
  2003年   3648篇
  2002年   3116篇
  2001年   2980篇
  2000年   2457篇
  1999年   1868篇
  1998年   1610篇
  1997年   1432篇
  1996年   864篇
  1995年   811篇
  1994年   701篇
  1993年   412篇
  1992年   358篇
  1991年   292篇
  1990年   252篇
  1989年   252篇
  1988年   220篇
  1987年   188篇
  1986年   157篇
  1985年   166篇
  1984年   90篇
  1983年   51篇
  1982年   91篇
  1981年   83篇
  1980年   73篇
  1979年   43篇
  1978年   32篇
  1977年   19篇
  1976年   12篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
AimsTreatment decisions for older patients with breast cancer are complex and evidence is largely extrapolated from younger populations. Frailty and comorbidity need to be considered. We studied the baseline characteristics and treatment decisions in older patients in Christchurch with breast cancer and assessed survival outcomes and prognostic/discriminatory performance of several tools.Materials and methodsWe searched the Canterbury Breast Cancer Registry and identified patients aged 70 years or older at diagnosis with invasive, non-metastatic breast cancer between 1 June 2009 and 30 June 2015. We retrieved demographics, treatment and outcome information. Overall survival and breast cancer-specific survival were estimated. Tools analysing performance status and comorbidity were assessed for their prognostic and discriminatory power.ResultsIn total, 440 patients were identified. Primary surgery was carried out for 362 patients (82.3%): breast-conserving surgery in 114 (of whom 88.6% received radiation therapy); mastectomy in 248 (of whom 24.6% received radiation). Hormone therapy was given for 265 (71.1%) patients with oestrogen receptor-positive cancers. Two hundred and seventy-four (62.3%) patients received full standard treatment, which was associated with significantly improved 5-year survival and 5-year breast cancer-specific survival. The median estimated overall survival was 8.2 years (95% confidence interval 7.3–9.1 years). Of those who died, 71.3% of deaths were due to causes other than breast cancer or unknown causes. The comorbidity-adjusted life expectancy (CALE) showed partial prognostic accuracy. CALE, Charlson and Eastern Cooperative Oncology Group tools all showed discriminatory value.ConclusionIn this population-based series of older patients with breast cancer, showing high levels of primary and adjuvant treatment, patients were more likely to die of causes other than breast cancer. Performance status and comorbidity tools showed prognostic and discriminatory potential in this population supporting their use in treatment decision making. CALE showed the most potential to improve treatment decisions but requires validation in this population to improve prognostic accuracy.  相似文献   
33.
目的筛选并分析与早发性乳腺癌发生、发展相关的靶基因。 方法(1)在美国国立生物技术信息中心的公共基因芯片数据库(GEO)中检索早发性乳腺癌样本及非早发性乳腺癌样本相关基因芯片数据。对上述数据使用GEO2R、R4.1.2及Venn软件筛选出相关差异表达基因(DEGs),并运用在线分析工具(Web Gestalt)对DEGs,进行相关功能和信号通路富集分析。(2)同时,通过String在线数据库构建DEGs编码的蛋白质-蛋白质相互作用(PPI)网络,并利用Cytohubba插件对该网络中的基因进行评分,筛选出枢纽基因。将枢纽基因导入Kaplan-Meier生存分析工具(Kaplan-Meier Plotter),评估枢纽基因在早发性乳腺癌的预后价值。(3)将肿瘤基因组图谱(TCGA)数据库中的肿瘤组织以年龄为标准进行分组,分析枢纽基因在各年龄组中的表达,并与正常组织中的表达进行比较,对得到的枢纽基因进行验证。DEGs表达量的多组间比较使用Kruskal-Wallis H检验,使用Bonferroni法进行两两比较。 结果(1)筛选出编号为GSE89116、GSE109169、GSE36295的基因芯片数据集,共得到80个差异表达基因,其中上调差异表达基因17个,下调差异表达基因63个。富集分析显示:DEGs主要富集在脂质代谢和氧化还原过程以及PPAR信号通路、AMPK信号通路上。(2)在PPI中发现主要的关键基因为PPARG、ADIPOQ、LIPE、PCK1、PDK4、ACACB、PLIN1、CAV1、CD36、ANGPTL4。ACACB、ADIPOQ、CAV1、LIPE、PLIN1、PPARG基因的低表达与乳腺癌患者的不良OS相关(HR=0.69、0.84、0.76、0.88、0.78、0.82;95%CI:0.59~0.80、0.76~0.93、0.67~0.83、0.79~0.97、0.70~0.86、0.73~0.90;P均<0.050)。(3)ACACB、ADIPOQ、LIPE、PLIN1、CAV1及PPARG这6个与预后相关的基因在正常组织中的表达量均远高于各年龄组肿瘤组织中的表达量(χ2=104.03、179.57、161.85、189.87、118.56、103.62,P均<0.001),早发性乳腺癌组(21~40岁)的LIPE、PLIN1表达量低于41~60岁、61~80岁年龄组,差异具有统计学意义(LIPE: Z=21.07、23.12, P均<0.050; PLIN1:Z=16.89、18.76, P均<0.050)。 结论早发性乳腺癌与非早发性乳腺癌存在差异基因表达谱,LIPE、PLIN1可能是早发性乳腺癌发生、发展的关键基因。  相似文献   
34.
The association between kidney function and cancer incidence is inconsistent among previous reports, and data on the Japanese population are lacking. It is unknown whether kidney function modifies the cancer risk of other factors. We aimed to evaluate the association of estimated glomerular filtration rate (eGFR) with cancer incidence and mortality in 55 242 participants (median age, 57 years; 55% women) from the Japan Multi-Institutional Collaborative Cohort Study. We also investigated differences in cancer risk factors between individuals with and without kidney dysfunction. During a median 9.3-year follow-up period, 4278 (7.7%) subjects developed cancer. Moderately low and high eGFRs were associated with higher cancer incidence; compared with eGFR of 60-74 ml/min/1.73 m2, the adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for eGFRs of ≥90, 75-89, 45-59, 30-44 and 10-29 ml/min/1.73 m2 were 1.18 (1.07-1.29), 1.09 (1.01-1.17), 0.93 (0.83-1.04), 1.36 (1.00-1.84) and 1.12 (0.55-2.26), respectively. High eGFR was associated with higher cancer mortality, while low eGFR was not; the adjusted subdistribution HRs (95% CIs) for eGFRs of ≥90 and 75-89 ml/min/1.73 m2 were 1.58 (1.29-1.94) and 1.27 (1.08-1.50), respectively. Subgroup analyses of participants with eGFRs ≥60 and <60 ml/min/1.73 m2 revealed elevated cancer risks of smoking and family history of cancer in those with eGFR <60 ml/min/1.73 m2, with significant interactions. Our findings suggest that the relationship between eGFR and cancer incidence was U-shaped. Only high eGFR was associated with cancer mortality. Kidney dysfunction enhanced cancer risk from smoking.  相似文献   
35.
《Radiography》2022,28(2):333-339
IntroductionDigital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen.MethodsThe mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters).ResultsIn the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view.ConclusionsFor the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts.Implications for practiceThe accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.  相似文献   
36.
37.
目的 前瞻性评估T1~T2期乳腺癌保乳术后化疗后程大分割放疗的不良反应和耐受性,以及在缩短治疗时间、减轻患者经济负担等方面的价值。方法 共入组20例T1~T2期乳腺癌保乳术后患者,所有患者于末次多西他赛化疗前开始大分割放疗。观察急性放射反应、治疗完成率及无病生存率、住院时间及住院费用等。结果 治疗完成率100%。主要不良反应为血液学毒性(白细胞减少)及皮肤反应,患者均可耐受。中位随访时间为30.1个月,随访率100%。美容效果良好率100%。平均总治疗时间为4周,总住院治疗费用节省约1万元。21个月无病生存率为100%。结论 T1~T2期乳腺癌保乳术后可耐受同步大分割放化疗,局部控制好,美容效果佳,且具有较高的卫生经济学价值。  相似文献   
38.
Breast cancer is the most common malignancy in women worldwide, with a relatively high proportion of patients experiencing resistance to standard treatments. Cellular immunotherapy (CI), which is based on the extraction, modification, and re-infusion of the patient’s immune cells, is showing promising results in these patients. Among CI possible approaches, adoptive cell therapy (ACT) and dendritic cell (DC) vaccination are the most comprehensively explored in both primary/translational research studies and clinical trials. ACT may include the use of tumor-infiltrating lymphocytes (TILs), T cell receptor (TCR)-, or chimeric antigen receptor (CAR)-engineered T-cells. There are indications suggesting that a biomarker-based approach might be beneficial in effectively selecting breast cancer patients for CI. Here, we sought to provide the current knowledge of CI in breast cancer, focusing on candidate biomarkers, ongoing clinical trials, limitations, and immediate future perspectives.  相似文献   
39.
Granulomatous slack skin is an indolent T-cell lymphoma, considered to be a variant of mycosis fungoides. Clinically it is characterized by areas of redundant skin, wrinkled, inelastic, with variable erythema and infiltration besides a poikilodermic surface. A differential diagnosis unknown to most dermatologists is the giant cell tumor of soft tissue, which is an extremely rare low-grade sarcoma. The authors report a patient who had undergone extensive surgery because of a primary diagnosis of giant cell tumor of soft tissue, but which proved to be granulomatous slack skin after a second interventional procedure with confirmatory histopathology.  相似文献   
40.
植物药对结肠癌具有良好的防治作用。姜黄素、多糖(苹果多糖、香菇多糖)、皂苷(重楼皂苷、人参皂苷)、白藜芦醇、槲皮素等植物药可通过不同信号通路抑制结肠癌细胞的增殖,促进细胞凋亡。此外,植物药还具有抗炎、抗氧化、抗血管生成、减轻化疗药物不良反应、逆转肿瘤细胞耐药等作用。了解植物药对结肠癌的防治作用及其可能的作用机制,能为结肠癌的临床防治提供更多的理论依据及治疗思路。  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