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   67242篇
  免费   6254篇
  国内免费   2607篇
耳鼻咽喉   741篇
儿科学   1610篇
妇产科学   1238篇
基础医学   7073篇
口腔科学   1413篇
临床医学   6186篇
内科学   6225篇
皮肤病学   1251篇
神经病学   2375篇
特种医学   3536篇
外国民族医学   62篇
外科学   8333篇
综合类   11466篇
现状与发展   21篇
预防医学   1807篇
眼科学   746篇
药学   4583篇
  47篇
中国医学   2001篇
肿瘤学   15389篇
  2024年   66篇
  2023年   962篇
  2022年   1489篇
  2021年   2686篇
  2020年   2360篇
  2019年   2120篇
  2018年   1977篇
  2017年   2249篇
  2016年   2531篇
  2015年   2727篇
  2014年   4136篇
  2013年   4261篇
  2012年   3744篇
  2011年   4184篇
  2010年   3361篇
  2009年   3372篇
  2008年   3390篇
  2007年   3654篇
  2006年   3301篇
  2005年   2969篇
  2004年   2573篇
  2003年   2202篇
  2002年   2028篇
  2001年   1825篇
  2000年   1501篇
  1999年   1342篇
  1998年   1109篇
  1997年   981篇
  1996年   863篇
  1995年   876篇
  1994年   753篇
  1993年   602篇
  1992年   515篇
  1991年   463篇
  1990年   359篇
  1989年   338篇
  1988年   311篇
  1987年   264篇
  1986年   211篇
  1985年   253篇
  1984年   234篇
  1983年   155篇
  1982年   186篇
  1981年   155篇
  1980年   123篇
  1979年   106篇
  1978年   74篇
  1977年   62篇
  1976年   51篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
BackgroundTo evaluate the association of neutrophil-to-lymphocyte ratio (NLR) with recurrence-free survival (RFS) and overall survival (OS) in patients with locally advanced nonmetastatic clear cell renal cell carcinoma (ccRCC) undergoing radical nephrectomy.Material and MethodsWe retrospectively identified 880 nephrectomies performed between January 2009 and December 2016 in a single center, reviewed data from 478 radical nephrectomies for kidney tumors and identified 187 patients with locally advanced nonmetastatic ccRCC (pT3-T4 N0M0). NLR was obtained preoperatively and calculated by dividing absolute neutrophil count by absolute lymphocyte count. OS and RFS were evaluated by the Kaplan–Meier method. Cox proportional-hazards regression models were used to evaluate predictors of RFS and OS.ResultsAmong 187 patients with ccRCC (mean age 63.4 ± 11.5 years; 118 [63.1%] male), the median follow-up was 48.7 months. On univariate analysis, in patients with Fuhrman nuclear grade of differentiation 3-4, the median time to recurrence was significantly shorter with NLR ≥ 4 than < 4 (24 vs. 55 months, P = .045). On multivariable analysis adjusted for NLR ≥ 4, among all variables analyzed (NLR, microvascular invasion, sarcomatoid differentiation, tumor size and body mass index), only nuclear grade of differentiation was an independent predictor of recurrence (hazard ratio 2.18; 95% confidence interval 1.07-4.92, P = .03). The 3-year OS had no statistically significant difference between patients with NLR ≥ 4 or < 4.ConclusionFor patients with locally advanced, nonmetastatic ccRCC, RFS was reduced with high nuclear grade of differentiation and high preoperative NLR. These findings suggest an association between higher NLR and worse outcomes in locally advanced ccRCC.  相似文献   
12.
13.
ObjectiveWe encountered a case of high-grade serous carcinoma (HGSC) of the ovary which recurred as carcinosarcoma of the sigmoid colon. Tumor cells of both the primary carcinoma and the secondary carcinosarcoma were negative for estrogen receptor (ER), WT-1, and PAX8. It is well known that most ovarian carcinomas arising from the Müllerian duct are immunoreactive for these biologic parameters. To our knowledge, this is the first case report that provides the results of immunohistochemical analysis of WT-1 and PAX8 for a primary carcinoma and recurrent carcinosarcoma.Case reportA 61-year-old woman had an advanced right ovarian HGSC. After a primary debulking surgery (hysterectomy, bilateral salpingo-oophorectomy and omentectomy) and adjuvant chemotherapy, complete remission was achieved. However, four and a half years later, a tumor arising beside the sigmoid colon was detected. A tumorectomy was performed through combined partial resection of the ileum and sigmoid colon. Microscopically, the tumor was diagnosed as carcinosarcoma of the sigmoid colon, which had originated from HGSC of the ovary. Interestingly, the malignant cells of the primary carcinoma and epithelial components of the recurrent carcinosarcoma were negative for ER, WT-1, and PAX8. These immunohistochemical features were unusual. Three cycles of chemotherapy with the previously used regimen and three additional cycles of doxorubicin and ifosfamide combination chemotherapy were administered. Currently, 3 years after the final chemotherapy was administered, the patient remains healthy.ConclusionHGSC of the ovary can recur as carcinosarcoma. Tumor cells of the primary HGSC without ER, WT-1, and PAX8 expression may have dedifferentiated and recurred as carcinosarcoma.  相似文献   
14.
植物花青素是一类可溶于水的类黄酮,主要存在于各种蔬菜水果中。常见的植物花青素主要分为天竺葵色素(Pelargonidin)、芍药色素(Peonidin)、矢车菊色素(Cyanidin)、锦葵色素(Malvidin)、矮牵牛色素(Petunidin)、飞燕草色素(Delphinidin)六种;植物花青素分子中含有共轭双键体系,并含有碱性或酸性基团,因而具有抗氧化、抗炎、调节免疫、抗衰老和抑癌等生物学作用,尤其以抑癌作用最为突出。因此,本文将对植物花青素的抑癌作用及可能的机制进行综述。  相似文献   
15.
吴文昊  李兴 《现代肿瘤医学》2022,(21):4022-4026
肝X受体(liver X receptors,LXRs)是孤儿核受体转录因子超家族成员,当LXRs被激活后,可调节靶基因的转录表达,不但参与胆固醇、脂肪、糖的代谢以及炎症等过程,并且在许多恶性肿瘤组织中均有表达。为全面了解肝X受体激动剂在治疗癌症中的研究现状,本文将从肝X受体激动剂与胃癌、肝癌、卵巢癌、乳腺癌、子宫内膜癌、肺癌以及结直肠癌的相关性方面进行综述。  相似文献   
16.
目的:探讨消化道肿瘤中同源重组修复相关基因(homologous recombination repair related gene,HRR)突变的发生情况及临床意义。方法:共92例消化道肿瘤患者,79例患者进行了血液标本HRR检测,53例患者进行了组织标本HRR检测,40例患者同时行血液和组织的HRR基因检测,收集患者基因检测结果及临床相关资料。结果:在79例患者血液标本检测中发现10例(12.6%)有临床意义HRR突变,在53例患者组织标本检测中发现9例(17.0%)有临床意义HRR突变。40例同时行血液和组织的HRR基因检测患者中常见的有临床意义HRR突变为CDK12突变4例(10.0%)、ATM突变3例(7.5%)、BRCA1突变2例(5.0%)。13例有临床意义HRR突变患者中常见共存突变为TP53突变10例(76.9%)、APC突变5例(38.5%)、PIK3CA突变4例(30.8%)。40例患者中13例患者血液和/或组织中有临床意义HRR突变,27例患者血液和组织中均无任何临床意义HRR突变且两组相比,有临床意义HRR突变组肿瘤突变负荷(tumor mutational burden,TMB)为6.17(2.24~11.52),而未携带HRR突变组TMB为0.4(0~3.75),差异有统计学意义(P<0.05)。40例患者组织检测中7例HRR有临床意义的突变,33例无HRR突变,血液检测中10例HRR有临床意义的突变,30例无HRR突变,一致性检验的Kappa值为0.333(P=0.031)。结论:携带有临床意义HRR突变的消化道肿瘤患者TMB更高,血液和组织检测HRR突变有较好的一致性。  相似文献   
17.
18.
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   
19.
20.
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