全文获取类型
收费全文 | 65521篇 |
免费 | 7047篇 |
国内免费 | 4377篇 |
专业分类
耳鼻咽喉 | 533篇 |
儿科学 | 992篇 |
妇产科学 | 473篇 |
基础医学 | 5189篇 |
口腔科学 | 1300篇 |
临床医学 | 8276篇 |
内科学 | 6835篇 |
皮肤病学 | 785篇 |
神经病学 | 2083篇 |
特种医学 | 2526篇 |
外国民族医学 | 12篇 |
外科学 | 5892篇 |
综合类 | 16201篇 |
现状与发展 | 22篇 |
一般理论 | 2篇 |
预防医学 | 7111篇 |
眼科学 | 863篇 |
药学 | 7687篇 |
95篇 | |
中国医学 | 6173篇 |
肿瘤学 | 3895篇 |
出版年
2024年 | 351篇 |
2023年 | 1135篇 |
2022年 | 2754篇 |
2021年 | 3410篇 |
2020年 | 2926篇 |
2019年 | 1812篇 |
2018年 | 1916篇 |
2017年 | 2180篇 |
2016年 | 1733篇 |
2015年 | 2869篇 |
2014年 | 3580篇 |
2013年 | 3891篇 |
2012年 | 5657篇 |
2011年 | 5987篇 |
2010年 | 4791篇 |
2009年 | 4197篇 |
2008年 | 4420篇 |
2007年 | 4472篇 |
2006年 | 3684篇 |
2005年 | 3007篇 |
2004年 | 2259篇 |
2003年 | 2257篇 |
2002年 | 1903篇 |
2001年 | 1602篇 |
2000年 | 1155篇 |
1999年 | 721篇 |
1998年 | 333篇 |
1997年 | 351篇 |
1996年 | 257篇 |
1995年 | 224篇 |
1994年 | 190篇 |
1993年 | 113篇 |
1992年 | 183篇 |
1991年 | 136篇 |
1990年 | 83篇 |
1989年 | 77篇 |
1988年 | 67篇 |
1987年 | 80篇 |
1986年 | 58篇 |
1985年 | 37篇 |
1984年 | 31篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 11篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的:鉴别益母草中是否含阿魏酸,方法:采用薄层色谱法和高效液相色谱法鉴别不同提取溶煤制备的样品,结果:从益母草中能检出阿魏酸。结论:益母草中可能含游离的阿魏酸,以5%Na2CO3溶液替代药典中的甲醇提取,方法简化,稳定性高,重现性好。 相似文献
52.
53.
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
54.
55.
56.
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
57.
58.
59.
软骨种子细胞的老化和缺乏是限制软骨组织工程在临床应用的瓶颈问题。本文概述了目前对软骨种子细胞研究的两个方面 :扩大种子细胞的来源及预防和延缓种子细胞功能老化 ,并展望软骨组织工程在监床的应用前景。 相似文献
60.
为寻找祖国医学治疗鼻咽癌的新途径,我们进行了气功外气对体外培养的人鼻咽低分化鳞癌细胞株(CNE—2)的抑制作用试验,实验共进行了三次,光镜观察受功组比对照组生长缓慢,外气对细胞生长的抑制率分别为33%(P<0.05);43%(P<0.05);55%(P<0.001)。同时进行了~3H—TdR掺入试验,观察外气对CNE—2细胞株DNA合成的影响。实验进行了四次,其抑制率分别为:34%(P<0.01);35%(P<0.01);39%(P<0.01),53%(P<0.001),模仿者为17%(P>0.05)。 相似文献