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   82668篇
  免费   6606篇
  国内免费   5076篇
耳鼻咽喉   1995篇
儿科学   257篇
妇产科学   2387篇
基础医学   4536篇
口腔科学   529篇
临床医学   8814篇
内科学   8177篇
皮肤病学   348篇
神经病学   577篇
特种医学   4872篇
外国民族医学   52篇
外科学   17240篇
综合类   14127篇
现状与发展   3篇
预防医学   2292篇
眼科学   228篇
药学   3605篇
  11篇
中国医学   306篇
肿瘤学   23994篇
  2024年   133篇
  2023年   881篇
  2022年   1822篇
  2021年   2447篇
  2020年   2328篇
  2019年   2010篇
  2018年   1858篇
  2017年   2133篇
  2016年   2842篇
  2015年   2607篇
  2014年   5071篇
  2013年   4305篇
  2012年   5389篇
  2011年   5926篇
  2010年   5167篇
  2009年   5044篇
  2008年   5033篇
  2007年   5555篇
  2006年   5143篇
  2005年   4954篇
  2004年   3833篇
  2003年   3356篇
  2002年   2877篇
  2001年   2758篇
  2000年   2268篇
  1999年   1693篇
  1998年   1430篇
  1997年   1275篇
  1996年   771篇
  1995年   679篇
  1994年   567篇
  1993年   331篇
  1992年   288篇
  1991年   236篇
  1990年   222篇
  1989年   199篇
  1988年   198篇
  1987年   168篇
  1986年   147篇
  1985年   114篇
  1984年   64篇
  1983年   37篇
  1982年   55篇
  1981年   39篇
  1980年   34篇
  1979年   20篇
  1978年   16篇
  1977年   11篇
  1976年   7篇
  1975年   5篇
排序方式: 共有10000条查询结果,搜索用时 121 毫秒
31.
IntroductionMajor hepatectomy (MH) is often needed in the curative management of intrahepatic cholangiocarcinoma (IHCC) and colorectal liver metastases (CRLM). While similar outcomes could be expected after MH for IHCC and CRLM, outcomes seem worse after MH for IHCC. A better understanding of such differences might help improving perioperative outcomes but comprehensive analysis are lacking.MethodsAll patients undergoing curative intent MH for IHCC or CRLM from 2003 to 2009 were included from two dedicated multi-institutional datasets. Preoperative management and short-term outcomes after MH were first compared. Independent predictors of postoperative mortality and morbidity were identified.ResultsAmong 827 patients, 333 and 494 patients underwent MH for IHCC and CRLM, respectively. Preoperative portal vein embolization was more frequently performed in the CRLM group (p < 0.001). MH in the IHCC group required more extended resection (p < 0.001). Postoperative mortality and severe morbidity rates were significantly higher in the IHCC group (7.2% vs. 1.2% and 29.7% vs. 11.1%, p < 0.001, respectively). Main causes for mortality were postoperative liver failure and deep surgical site infection. MH for IHCC was an independent risk factor for mortality (p < 0.001) and severe morbidity (p < 0.001). After propensity score matching (212 patients in each group), the aforementioned differences regarding outcomes remained statistically significant.ConclusionThis study suggests that IHCC patients are inherently more at risk after MH as compared to CRLM patients. Considering that postoperative liver failure was the most frequent cause of death, preoperative planning might have been inadequate in the setting of IHCC while more complex/extended resections should be expected.  相似文献   
32.
33.
It is clinically challenging to identify oral leukoplakias that have a high risk of undergoing malignant transformation. The aim of this retrospective study was to elucidate the associations between malignant transformation of oral leukoplakias and various clinicopathologic factors. Patients with a diagnosis of clinical oral leukoplakia, verified through histopathologic examination and with access to digital images of the lesion, were retrospectively included for the period 2003–2013. Using the clinical images, all lesions were re-evaluated regarding diagnosis and clinical subtype. Of the 234 included patients, with a median follow-up of 9 years, 27 (11.5%) developed oral squamous cell carcinoma. Among the clinicopathologic factors investigated, non-homogeneous oral leukoplakia (OL), OL with dysplasia, and OL localized to the tongue showed statistically significant increased rates of malignant transformation in the multivariate Cox regression analysis. Non-homogeneous OL showed a 15.2-times higher transformation rate than homogenous OL (P < 0.001). Dysplastic leukoplakias developed into carcinomas 2.4-times more often than did non-dysplastic leukoplakias (P = 0.048). OL located on the tongue showed a 2.8-times higher malignant transformation rate than OLs at other oral locations (P = 0.018), when other locations were combined into one group. Non-homogeneous OL, OL with dysplasia, and OL localized to the tongue have higher transformation rates.  相似文献   
34.
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   
35.
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   
36.
37.
38.
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   
39.
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   
40.
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