全文获取类型
收费全文 | 331806篇 |
免费 | 33616篇 |
国内免费 | 20273篇 |
专业分类
耳鼻咽喉 | 3032篇 |
儿科学 | 4259篇 |
妇产科学 | 3156篇 |
基础医学 | 31285篇 |
口腔科学 | 6062篇 |
临床医学 | 42170篇 |
内科学 | 39506篇 |
皮肤病学 | 3761篇 |
神经病学 | 13114篇 |
特种医学 | 12476篇 |
外国民族医学 | 98篇 |
外科学 | 32384篇 |
综合类 | 70812篇 |
现状与发展 | 81篇 |
一般理论 | 22篇 |
预防医学 | 30479篇 |
眼科学 | 6494篇 |
药学 | 37734篇 |
451篇 | |
中国医学 | 26217篇 |
肿瘤学 | 22102篇 |
出版年
2025年 | 53篇 |
2024年 | 4727篇 |
2023年 | 6148篇 |
2022年 | 12918篇 |
2021年 | 15791篇 |
2020年 | 12981篇 |
2019年 | 9286篇 |
2018年 | 9616篇 |
2017年 | 10227篇 |
2016年 | 8825篇 |
2015年 | 14177篇 |
2014年 | 17733篇 |
2013年 | 18849篇 |
2012年 | 27299篇 |
2011年 | 29343篇 |
2010年 | 22694篇 |
2009年 | 19249篇 |
2008年 | 22004篇 |
2007年 | 21011篇 |
2006年 | 19259篇 |
2005年 | 16659篇 |
2004年 | 11448篇 |
2003年 | 9896篇 |
2002年 | 7954篇 |
2001年 | 7084篇 |
2000年 | 6402篇 |
1999年 | 4775篇 |
1998年 | 2478篇 |
1997年 | 2483篇 |
1996年 | 1937篇 |
1995年 | 1862篇 |
1994年 | 1638篇 |
1993年 | 997篇 |
1992年 | 1339篇 |
1991年 | 1162篇 |
1990年 | 933篇 |
1989年 | 881篇 |
1988年 | 796篇 |
1987年 | 659篇 |
1986年 | 498篇 |
1985年 | 419篇 |
1984年 | 210篇 |
1983年 | 176篇 |
1982年 | 119篇 |
1981年 | 125篇 |
1980年 | 80篇 |
1979年 | 110篇 |
1978年 | 52篇 |
1977年 | 51篇 |
1974年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的 探讨益气补肾方含药血清对人胃癌细胞SGC-7901增殖转移能力及CD44+EpCAM+干细胞比例的影响。方法 分别以低、中、高不同浓度益气补肾方含药血清及空白血清干预人胃癌细胞SGC-7901。采用MTT法检测24,48,72 h细胞增殖抑制率,Transwell小室检测胃癌细胞迁移侵袭能力。采用5-氟尿嘧啶(5-Fu)共培养富集胃癌干细胞,流式细胞术检测药物干预后CD44+EpCAM+干细胞比例。结果 干预48,72 h后,益气补肾方组细胞增殖抑制率显著高于同时期阴性对照组及空白对照组,差异有统计学意义(P<0.05)。Transwell结果显示,与阴性对照组和空白对照组比较,益气补肾方各组透膜细胞数显著降低,迁移能力受明显抑制,差异有显著统计学意义(P<0.01)。流式细胞术结果显示,终浓度为20 μg·mL-1的5-Fu共培养24 h后,胃癌干细胞比例显著提升,益气补肾方干预后各组细胞中CD44+EpCAM+干细胞比例均下调,中、高浓度组与模型对照组相比,差异有显著统计学意义(P<0.01)。结论 益气补肾方含药血清能显著抑制人胃癌细胞SGC-7901增殖,并呈时间、剂量相关性,其抗转移作用可能与下调胃癌干细胞表面标志物CD44、EpCAM表达,降低CD44+EpCAM+干细胞比例有关。 相似文献
42.
Ji-Wu Huang Fang-You Chen Chuang-Jun Li Jing-Zhi Yang Jie Ma Xiao-Guang Chen 《Journal of Asian natural products research》2018,20(4):337-343
Two new saponins, notoginsenosides Ng1 (1) and Ng2 (2), together with seven known compounds (3–9), were isolated from the leaves of Panax notoginseng. Their structures were elucidated by UV, IR, HRESIMS, and NMR experiments. Compounds 6 and 7 showed moderate cytotoxic activities against HCT-116, with IC50 values of 4.98 and 0.64 μmol/L, respectively. 相似文献
43.
Huilong Wen Zhong Wu Huidong Hu Yixiong Wu Gang Yang Jiajun Lu Guang Yang Gang Guo Qirong Dong 《Journal of natural medicines》2018,72(1):57-63
Pachymic acid (PA) is a lanostane type triterpenoid isolated from Poria cocos, which possesses an anti-tumor effect in breast cancer, prostate cancer, lung cancer, and bladder cancer cells. In this study, we investigated the effect of PA on the growth and apoptosis of human immortalized cell line (HOS) and primary osteosarcoma cells by a Cell Counting Kit-8 (CCK-8) and Annexin V and propidium iodide (PI) staining, respectively. Western blot was used to measure the expression of cleaved Caspase 3, PTEN, and AKT, as well as the AKT phosphorylation. The Caspase 3 activity was determined using the Caspase-3 Colorimetric Assay Kit. From the results, PA significantly reduced cell proliferation in a concentration- and time-dependent manner. PA also induced cell apoptosis in a dose-dependent fashion. PA treatment led to increased Caspase 3 activation and PTEN expression, as well as reduced AKT phosphorylation. Moreover, Ac-DEVD-CHO (a Caspase 3/7 inhibitor) pre-treatment or PTEN knockdown partially blocked the effects of PA on cell proliferation and apoptosis. Caspase 3/7 inhibitor had an additive effect with PTEN knockdown. Collectively, our results suggested that induction of apoptosis by PA was mediated in part by PTEN/AKT signaling and Caspase 3/7 activity. This study provides evidence that PA might be useful in the treatment of human osteosarcoma. 相似文献
44.
45.
Yang Zhang Bowen Deng Yida Cui Xue Chen Jiayi Bi Guogang Zhang 《Journal of natural medicines》2018,72(4):946-953
Two new secoiridoid glucosides, ilexpublignoside (1), pubzenoside (2), and a new lignan, ilexlignan B (3), along with seven known compounds (4–10) were isolated from the roots of Ilex pubescens for the first time. Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including IR, UV, HR-ESI–MS, CD, NMR experiments, as well as comparison with the reported data. 相似文献
46.
目的 掌握广西辖区内糖厂密封放射源的使用分布情况,评价密封放射源对周围环境、职业人员、公众成员产生的辐射影响,为今后糖厂放射源的使用管理提供科学依据。方法 按监测规范合理布点,利用γ辐射剂量率仪对广西区内所有使用密封放射源的糖厂开展辐射环境现场测量,根据监测结果进行估算,并结合个人剂量监测结果进行分析。结果 密封放射源使用场所周围辐射剂量率高于环境本底水平,职业人员、公众成员会受到一定的辐射剂量。结论 职业人员及公众成员年有效剂量结果符合相关要求。 相似文献
47.
Comparative Efficacy and Safety of Phosphate Binders in Hyperphosphatemia Patients With Chronic Kidney Disease 下载免费PDF全文
Xiuqin Yang MD Qingning Bai MD Yanguo Li MD Haijun Liu MD Haiying Guo MD Xiaolei Zhang MD 《JPEN. Journal of parenteral and enteral nutrition》2018,42(4):766-777
Background: In this study, we coordinated a network meta‐analysis to establish the efficacy and safety of different agents used in the treatment of hyperphosphatemia patients with chronic kidney disease. Methods: PubMed, CNKI, and Embase were systematically searched to retrieve relevant studies. Outcomes were presented by mean differences, odds ratios, and corresponding 95% credible intervals for continuous outcomes and binary outcomes, respectively. Each therapy was ranked according to the value of surface under the cumulative ranking curve. Consistencies between direct and indirect comparisons were assessed with a node‐splitting plot. Results: In terms of efficacy end points (including levels of serum phosphate, serum calcium, serum intact parathyroid hormone, and serum calcium × phosphorus product), all 7 kinds of agents outperformed or performed at least equally to placebo, with iron‐based phosphate‐binding agents being potentially the most effective. As for safety end points (including mortality, adverse events, and all‐cause discontinuation), almost all agents were equivalent in term of mortality and all‐cause discontinuation except in the comparison between iron‐based phosphate‐binding agents and placebo. Meanwhile, iron‐based phosphate‐binding agents colestilan and nicotinic acid performed poorly compared with placebo in terms of adverse events. Furthermore, iron‐based phosphate‐binding agents were potentially the safest agents followed sequentially by calcium‐based phosphate‐binding agents and placebo. Conclusion: Iron‐based phosphate‐binding agents were the preferable agents when considering efficacy and safety simultaneously. 相似文献
48.
49.
Xinxin Liu Jian Yang Shuang Song Hong Song Danni Ai Jianjun Zhu Yurong Jiang Yongtian Wang 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2018,41(2):495-505
50.