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   196117篇
  免费   18606篇
  国内免费   7508篇
耳鼻咽喉   1194篇
儿科学   4627篇
妇产科学   2686篇
基础医学   37204篇
口腔科学   3775篇
临床医学   12342篇
内科学   33474篇
皮肤病学   3245篇
神经病学   16078篇
特种医学   3718篇
外国民族医学   57篇
外科学   14314篇
综合类   24129篇
现状与发展   30篇
预防医学   8860篇
眼科学   2296篇
药学   26034篇
  21篇
中国医学   6775篇
肿瘤学   21372篇
  2024年   504篇
  2023年   3089篇
  2022年   6322篇
  2021年   7993篇
  2020年   6748篇
  2019年   7744篇
  2018年   7347篇
  2017年   7240篇
  2016年   7084篇
  2015年   8505篇
  2014年   11860篇
  2013年   13247篇
  2012年   12188篇
  2011年   14449篇
  2010年   12287篇
  2009年   11653篇
  2008年   11052篇
  2007年   9843篇
  2006年   8909篇
  2005年   7591篇
  2004年   6646篇
  2003年   5644篇
  2002年   4374篇
  2001年   3731篇
  2000年   3085篇
  1999年   2802篇
  1998年   2402篇
  1997年   2179篇
  1996年   1883篇
  1995年   1583篇
  1994年   1381篇
  1993年   1163篇
  1992年   969篇
  1991年   867篇
  1990年   714篇
  1989年   599篇
  1988年   513篇
  1987年   415篇
  1986年   422篇
  1985年   796篇
  1984年   821篇
  1983年   574篇
  1982年   644篇
  1981年   508篇
  1980年   418篇
  1979年   365篇
  1978年   280篇
  1977年   221篇
  1976年   206篇
  1975年   142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).  相似文献   
92.
93.
94.
IntroductionEGFR mutated (EGFRm) NSCLC tumors occasionally express programmed cell death ligand 1 (PD-L1), although frequency and clinical relevance are not fully characterized. We report PD-L1 expression in patients with EGFRm advanced NSCLC and association with clinical outcomes following treatment with osimertinib or comparator EGFR tyrosine kinase inhibitors in the FLAURA trial (phase III, NCT02296125).MethodsOf 231 tissue blocks available from the screened population (including EGFRm-positive and -negative samples), 197 had sufficient tissue for PD-L1 testing using the SP263 (Ventana, Tucson, Arizona) immunohistochemical assay. Tumor cell (TC) staining thresholds of PD-L1 TC greater than or equal to 1%, TC greater than or equal to 25%, and TC greater than or equal to 50% were applied. Progression-free survival (PFS) was investigator-assessed, per Response Evaluation Criteria in Solid Tumor, version 1.1, according to PD-L1 expressors (TC ≥ 1%) or negatives (TC < 1%) in randomized patients.ResultsPD-L1 staining was successful in 193 of 197 patient formalin-fixed paraffin-embedded blocks; of these, 128 of 193 were EGFRm-positive and 106 of 128 patients were randomized to treatment (osimertinib: 54; comparator: 52). At the PD-L1 TC greater than or equal to 25% threshold, 8% (10 of 128) of EGFRm-positive tumors expressed PD-L1 versus 35% (23 of 65) of EGFRm-negative tumors. With the TC greater than or equal to 1% threshold, 51% (65 of 128) versus 68% (44 of 65) were mutation-positive and –negative, respectively, and with the TC greater than or equal to 50% threshold, 5% (7 of 128) versus 28% (18 of 65), were mutation-positive and -negative, respectively. For PD-L1 expressors (TC ≥ 1%), median PFS was 18.4 months with osimertinib and 6.9 months with comparator (hazard ratio = 0.30; 95% confidence interval: 0.15–0.60). For PD-L1–negative patients (TC < 1%), median PFS was 18.9 months with osimertinib and 10.9 months with comparator (hazard ratio = 0.37; 95% confidence interval: 0.17–0.74).ConclusionsClinical benefit with osimertinib was unaffected by PD-L1 expression status.  相似文献   
95.
Neuronal growth regulator 1 (NEGR1), a member of the immunoglobulin superfamily cell adhesion molecule subgroup IgLON, has been involved in neuronal growth and connectivity. Genetic variants, in or near the NEGR1 locus, have been associated with obesity and, more recently, with learning difficulties, intellectual disability, and psychiatric disorders.Here, we described the only second report of NEGR1 gene disruption in 1p31.1 microdeletion in two patients. Patient 1 is a 14-year-old female with neurological and psychiatric features present also in her family. Patient 2 is a 5-month-old infant showing global hypotonia as unique neurological features till now. This patient also carries 7p22.1 duplication, of paternal origin, that could be responsible for some malformations present in the child.We hypothesize a role of NEGR1 in producing the phenotype of our patients and compare them with other cases previously reported in the literature and DECIPHER database to better identify a possible genotype-phenotype correlation.  相似文献   
96.
《药学学报(英文版)》2020,10(7):1294-1308
A great challenge in multi-targeting drug discovery is to identify drug-like lead compounds with therapeutic advantages over single target inhibitors and drug combinations. Inspired by our previous efforts in designing antitumor evodiamine derivatives, herein selective histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) dual inhibitors were successfully identified, which showed potent in vitro and in vivo antitumor potency. Particularly, compound 30a was orally active and possessed excellent in vivo antitumor activity in the HCT116 xenograft model (TGI = 75.2%, 150 mg/kg, p.o.) without significant toxicity, which was more potent than HDAC inhibitor vorinostat, TOP inhibitor evodiamine and their combination. Taken together, this study highlights the therapeutic advantages of evodiamine-based HDAC1/TOP2 dual inhibitors and provides valuable leads for the development of novel multi-targeting antitumor agents.  相似文献   
97.
98.
目的 探讨类风湿关节炎患者外周血miR-150-5p、细胞因子信号抑制因子1(suppressor of cytokine signaling 1,SOCS1)mRNA的表达及对类风湿关节炎(Rheumatoid Arthritis,RA)疾病诊断、中医证型判断的意义。方法 纳入符合诊断标准的RA患者57例及健康对照组19例,根据《22个专业95个病种中医诊疗方案》有关RA的中医证候诊断标准,判断RA的中医证型。qPCR检测RA患者及健康对照组miR-150-5p、SOCS1mRNA的相对表达水平,同时检测血常规、肝功能、肾功能等常规指标。双荧光素酶分析方法判断两者是否存在靶向关系。统计分析miR-150-5p、SOCS1 mRNA对RA疾病的诊断意义及其与中医证型的相关性。结果 RA患者外周血miR-150-5p的相对表达水平下调,低于正常人群(t = -19.019,P < 0.05);其表达水平随疾病活动度升高,有下降趋势;患者外周血SOCS1 mRNA的相对表达水平上调,低于正常人群(t = 5.333,P < 0.05);其表达水平随疾病活动度升高,有上升趋势。MiR-150-5p与SOCS1 mRNA有靶向结合关系(P < 0.05)。通过AUC曲线比较,miR-150-5p的相对表达水平区分RA的敏感性及特异性分别为98.1%、92.1%(AUC = 0.972,P < 0.05);SOCS1 mRNA的相对表达水平无法区分RA(AUC = 0.472,P > 0.05)。RA患者中miR-150-5p的相对表达水平低于3.06,RA患者风湿痹阻证、寒湿痹阻证的相对风险分别为8.33、250.00(P < 0.05)。结论 miR-150-5p、SOCS1 mRNA在RA患者中有差异性表达,且有靶向结合关系。miR-150-5p可能是RA的疾病诊断及中医风湿痹阻证、寒湿痹阻证证型诊断的潜在生物标志物。  相似文献   
99.
目的:总结富亮氨酸胶质瘤失活1蛋白(LGI1)抗体阳性边缘性脑炎的临床和影像特点及诊疗预后。 方法:报道我院1例LGI1抗体阳性相关边缘性脑炎并文献复习。结果:患者女性,60岁,表现为渐进性加重 的记忆力减退、癫痫发作(全身强直阵挛发作,面-臂肌张力障碍发作)、低钠血症和轻度精神行为异常。颅 脑MRI-T2/Flair序列提示双侧颞叶(左侧为甚)内侧、海马异常高信号。脑脊液抗LGI1抗体阳性(++)。经激 素治疗症状有所改善。检索既往报道LGI1抗体阳性边缘性脑炎患者237例,多数呈急性、亚急性起病,最 常见是记忆障碍、癫痫(含面-臂肌张力障碍发作)和低钠血症,头颅MRI(特别是MRI-T2/Flair序列)显示单 侧或者双侧海马区、颞叶异常多见,早期免疫治疗预后良好。结论:LGI1抗体阳性相关边缘性脑炎有其特 有的临床特点,免疫治疗可明显改善患者预后。  相似文献   
100.
《Cancer cell》2021,39(11):1497-1518.e11
  1. Download : Download high-res image (282KB)
  2. Download : Download full-size image
  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