全文获取类型
收费全文 | 27796篇 |
免费 | 3111篇 |
国内免费 | 2016篇 |
专业分类
耳鼻咽喉 | 172篇 |
儿科学 | 315篇 |
妇产科学 | 292篇 |
基础医学 | 3006篇 |
口腔科学 | 601篇 |
临床医学 | 3737篇 |
内科学 | 3651篇 |
皮肤病学 | 338篇 |
神经病学 | 1307篇 |
特种医学 | 926篇 |
外国民族医学 | 12篇 |
外科学 | 2551篇 |
综合类 | 5520篇 |
现状与发展 | 7篇 |
一般理论 | 2篇 |
预防医学 | 2247篇 |
眼科学 | 590篇 |
药学 | 3080篇 |
45篇 | |
中国医学 | 2433篇 |
肿瘤学 | 2091篇 |
出版年
2024年 | 201篇 |
2023年 | 673篇 |
2022年 | 1605篇 |
2021年 | 1889篇 |
2020年 | 1546篇 |
2019年 | 1094篇 |
2018年 | 1123篇 |
2017年 | 1104篇 |
2016年 | 920篇 |
2015年 | 1337篇 |
2014年 | 1626篇 |
2013年 | 1446篇 |
2012年 | 2048篇 |
2011年 | 2120篇 |
2010年 | 1412篇 |
2009年 | 1174篇 |
2008年 | 1215篇 |
2007年 | 1308篇 |
2006年 | 1145篇 |
2005年 | 1030篇 |
2004年 | 897篇 |
2003年 | 1079篇 |
2002年 | 980篇 |
2001年 | 802篇 |
2000年 | 532篇 |
1999年 | 477篇 |
1998年 | 302篇 |
1997年 | 334篇 |
1996年 | 252篇 |
1995年 | 215篇 |
1994年 | 170篇 |
1993年 | 102篇 |
1992年 | 170篇 |
1991年 | 132篇 |
1990年 | 80篇 |
1989年 | 84篇 |
1988年 | 64篇 |
1987年 | 74篇 |
1986年 | 46篇 |
1985年 | 37篇 |
1984年 | 30篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
61.
Xue Peng Zhang Yong Wang Xiaoyan Cui Yuanshan Wei Guangzhu Liu Xuehuan 《Transplantation proceedings》2021,53(1):436-442
ObjectivesTo investigate the effect and mechanism of macrophage activation and graft damage caused by nucleoside triphosphate diphosphohydrolase 1 (NTPDase1) in acute antibody-mediated rejection (AMR).MethodsAcute AMR was induced in different skin-grafted nude mouse models with wild-type NTPDase1 expression, transgene-enhanced NTPDase1 expression, or NTPDase1 gene knockout. Several methods (eg, real-time fluorescence quantitative polymerase chain reaction, high-performance liquid chromatography [HPLC], immunofluorescence, flow cytometry, and luciferin/luciferase assays) were used to study (at the histologic and molecular levels) the extracellular adenosine diphosphate (ADP) concentration, macrophage proliferation, major histocompatibility complex (MHC) class II antigen expression on the surface of macrophages, B-cell activating factor (BAFF) expression in the peripheral blood serum, and the total number of SmIg-positive B cells during acute AMR. The relative activity of NTPDase1 in B cells and epithelial cells, pathologic changes, and the incidence of positive C4d deposition around the capillaries of skin grafts on the different nude mice were studied.ResultsMacrophages proliferated significantly when acute AMR occurred. The higher the NTPDase1 expression level, the lower the extracellular ADP concentration, the expression of MHC class II antigens on the surface of macrophages, the expression of BAFF in the peripheral blood serum, and the total number of SmIg-positive B cells, indicating negative correlations. The relative activity of NTPDase1 in B cells and epithelial cells of the skin graft was different among the different mice. The higher the NTPDase1 expression level, the lower the degree of pathologic damage to the skin graft.ConclusionsImbalance in extracellular ADP degradation by NTPDase1 may promote macrophage activation, and activated macrophages may be an important cause of graft damage. 相似文献
62.
63.
Xu Li Siming Li Zhihong Chi Chuanliang Cui Lu Si Xieqiao Yan Lili Mao Bin Lian Bixia Tang Xuan Wang Xue Bai Li Zhou Yan Kong Jie Dai Jun Guo Xinan Sheng 《Urologic oncology》2021,39(1):75.e1-75.e8
PurposeTo investigate the clinical characteristics, chemosensitivity, and outcome of metastatic upper tract urothelial carcinoma (UTUC).Patients and MethodsRecords of patients with metastatic UTUC since January 2005 were retrieved from a database that included clinical and survival data. Statistical analyses including survival and multivariate analyses of factors were respectively performed by the Kaplan-Meier method and Cox proportional hazard model.ResultsA total of 250 consecutive UTUC cases were evaluated. There were 56 patients (22.4%) with initially diagnosed stage IV disease. The most common metastatic sites were lung (39.6%), distant lymph nodes (39.2%), bone (19.6%), liver (18.0%), and adrenal gland (7.2%), respectively, and the local recurrence rate was 10.4%. Two hundred thirteen patients received first-line chemotherapy. The overall response rate was only 28.7% and the median progression-free survival time was only 5.0 months. The overall survival time of the cohort was 18.0 months. Multivariate analyses showed that initially diagnosed stage IV disease, number of metastatic organs ≥3, no response to chemotherapy and cycles of chemotherapy ≤2 were adverse prognosticators for overall survival.ConclusionUTUC presented to be more prone to metastasize than locally recur and thought to have low chemosensitivity. Stage IV disease at initial diagnosis, number of metastatic organs, response and cycles of chemotherapy were independent prognosticators for metastatic UTUC. 相似文献
64.
65.
Li Yiwei Li Qihou Sun Wei Peng Zhihong Millar Graeme J. Xue Shengguo Jiang Jun 《Bulletin of environmental contamination and toxicology》2022,109(1):20-29
Bulletin of Environmental Contamination and Toxicology - Bauxite residue is a highly alkaline waste from alumina refining, and is mainly disposed by stacking with high environmental risks.... 相似文献
66.
67.
目的 :探讨不同压力的高压氧处理后 ,幼龄小鼠对新异环境的探究行为和自发活动的变化以及分辨学习的影响。方法 :用开场行为模型和Y 迷宫分辨学习模型观察小鼠的各项行为指标。结果 :与对照相比 ,吸 10 1 3kPa高压氧的幼龄小鼠学习记忆能力明显提高 ;吸 2 5 3 3kPa高压氧的幼龄小鼠学习记忆能力无明显变化 ,但其在新异环境中的自发行为明显减少。结论 :实验结果提示 :慢性吸入 10 1 3kPa高压氧有益于幼龄小鼠脑的生长发育 ,增强脑功能活动 ,但其作用机制还有待于进一步研究 相似文献
68.
In recent years, the most exciting advance inthe research of human pitllitary tumors is the discovery that 30 %--40 % of hfuman pituitary somatotrophinomas carry somatic missense single--basemutations within codons 201 and 227 of the genefor the a--subunit of the stimulatory GTP--bindingprotein, Gs (Gsa). These mutations, termed gsponcogenes, result in constitutive activity of adenylyl cyclase and the subsequent elevations in intracellular cAMP levels are thought to be responsiblefor tumor g… 相似文献
69.
70.