全文获取类型
收费全文 | 213054篇 |
免费 | 21088篇 |
国内免费 | 14879篇 |
专业分类
耳鼻咽喉 | 2141篇 |
儿科学 | 2931篇 |
妇产科学 | 1926篇 |
基础医学 | 20067篇 |
口腔科学 | 3782篇 |
临床医学 | 26528篇 |
内科学 | 26871篇 |
皮肤病学 | 2257篇 |
神经病学 | 8776篇 |
特种医学 | 7887篇 |
外国民族医学 | 98篇 |
外科学 | 21386篇 |
综合类 | 45448篇 |
现状与发展 | 67篇 |
一般理论 | 12篇 |
预防医学 | 17973篇 |
眼科学 | 4859篇 |
药学 | 23090篇 |
258篇 | |
中国医学 | 16325篇 |
肿瘤学 | 16339篇 |
出版年
2024年 | 861篇 |
2023年 | 3215篇 |
2022年 | 8184篇 |
2021年 | 10552篇 |
2020年 | 8348篇 |
2019年 | 6452篇 |
2018年 | 6848篇 |
2017年 | 6979篇 |
2016年 | 6484篇 |
2015年 | 10220篇 |
2014年 | 12336篇 |
2013年 | 12612篇 |
2012年 | 18223篇 |
2011年 | 19500篇 |
2010年 | 14495篇 |
2009年 | 12168篇 |
2008年 | 13642篇 |
2007年 | 12951篇 |
2006年 | 12199篇 |
2005年 | 10452篇 |
2004年 | 7405篇 |
2003年 | 6998篇 |
2002年 | 5785篇 |
2001年 | 4490篇 |
2000年 | 3635篇 |
1999年 | 2964篇 |
1998年 | 1719篇 |
1997年 | 1622篇 |
1996年 | 1298篇 |
1995年 | 1209篇 |
1994年 | 933篇 |
1993年 | 578篇 |
1992年 | 648篇 |
1991年 | 531篇 |
1990年 | 460篇 |
1989年 | 360篇 |
1988年 | 343篇 |
1987年 | 308篇 |
1986年 | 229篇 |
1985年 | 178篇 |
1984年 | 89篇 |
1983年 | 74篇 |
1982年 | 53篇 |
1981年 | 52篇 |
1980年 | 27篇 |
1979年 | 57篇 |
1978年 | 26篇 |
1977年 | 21篇 |
1974年 | 23篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
我科自1981年3月至1991年12月应用吻合器行中、下段直肠癌切除术67例,同期发生吻合口漏10例(149%)。本文分析了吻合口漏发生的因素。病变部位、病灶范围、术中操作技术、术前肠道灌洗以及术后骶前引流是影响吻合口漏的重要因素。本文总结了吻合口漏的治疗方法,提倡保守治疗,或加作暂时性横结肠造口术。 相似文献
43.
E P Wei R Kukreja H A Kontos 《Stroke; a journal of cerebral circulation》1992,23(11):1623-8; discussion 1628-9
BACKGROUND AND PURPOSE: We investigated the chemical identity of the endothelium-derived relaxing factor generated by acetylcholine in cerebral microvessels by studying the effects and mechanism of action of inhibitors of nitric oxide synthesis from arginine on the vasodilation and endothelium-derived relaxing factor production induced by topical application of acetylcholine in cerebral arterioles. METHODS: We determined cerebral arteriolar dilation and endothelium-derived relaxing factor production by bioassay in anesthetized cats equipped with cranial windows during superfusion of 10(-7) M acetylcholine before and after administration of either NG-monomethyl L-arginine or NG-nitro-L-arginine, two inhibitors of nitric oxide synthesis. RESULTS: NG-Nitro-L-arginine abolished the vasodilation from acetylcholine and eliminated the production of endothelium-derived relaxing factor in the bioassay experiments. NG-Monomethyl L-arginine had no effect on the response to acetylcholine in the absence of pretreatment. However, after pretreatment with the detergent sodium dodecyl sulfate to increase cell membrane permeability, the inhibitor had effects identical to those of NG-nitro-L-arginine. L-Arginine reversed the effects of the inhibitors of nitric oxide synthesis. Neither inhibitor affected baseline vascular caliber, nor did they generate a vasoconstrictor agent in the bioassay experiments. The two inhibitors of nitric oxide synthesis did not affect the response to nitroprusside or adenosine, showing that the effect on responses to acetylcholine was specific. Also, the blockade of the response to acetylcholine induced by the inhibitors of nitric oxide synthesis was unaffected by treatment with superoxide dismutase and catalase, showing that the effect was not mediated by oxygen radicals. CONCLUSION: The endothelium-derived relaxing factor generated by acetylcholine in cerebral arterioles of cats is either nitric oxide or a nitric oxide-containing substance. The effect of these inhibitors on the response to acetylcholine is mediated by inhibition of the synthesis of nitric oxide. There is no involvement of radicals, and no vasoconstrictor agent is generated. 相似文献
44.
45.
46.
老年2型糖尿病患者胰岛素抵抗相关指标的检测和意义 总被引:1,自引:1,他引:0
目的:探讨老年2型糖尿病胰岛素抵抗(IR)及其相关性,为老年2型糖尿病的合理防治提供临床依据。方法:选择120例老年2型糖尿病患者,按胰岛素敏感指数(HOMA)胰岛素抵抗(HOMA-IR)50百分位点将患者分为两组:胰岛素相对敏感组(HOMA-IR<3.56)和胰岛素相对抵抗组(HOMA-IR≥3.56),比较体重指数(BMI)、腰/臀比(WHR)、血压、血生化学检查等指标。用年龄>40岁,<60岁的2型糖尿病患者做对照组。结果:两组老年患者在年龄、性别、舒张压、空腹血糖、胆固醇、高密度脂蛋白、糖化血红蛋白、HOMA胰岛β细胞功能方面无差异;但BMI、WHR、收缩压、甘油三脂、空腹胰岛素、HOMA-IR差异具有显著性。多线性回归分析后,只有腰/臀比、收缩压、甘油三脂、HOMA-IR存在统计学差异。老年患者与对照组相比,IR发生率明显增加,且两者腰/臀比、收缩压、甘油三脂方面也差异显著。结论:IR与老年2型糖尿病密切相关,是临床防治糖尿病的重要靶点。 相似文献
47.
48.
Objective: To study the calcium channel reaction of human Leydig cells induced by hCG/ATP at different extracellular calcium ion concentrations. Methods: The Leydig cell calcium ion concentration was examined with laser confocal microscope, when the cells were stimulated with hCG/ATP at different extracellular calcium contrations. Results: With calcium-containing extracellular fluid, the Leydig cells were sensitive to hCG stimulation and when the extracellular fluid was calcium-free, the Leydig cells did not respond to the stimulation. However, the Leydig cells did respond to ATP stimulation no matter the extracellular fluid contained calcium or not. Conclusion: In human Leydig cells, there are calcium channels sensitive to hCG and ATP. The extracellular calcium ion concentration plays an important role in the regulation of Leydig cell metabolism by hCG/ATP. 相似文献
49.
50.
Objective: To analyze quantitatively the synergistic and antagonistic effects of combined oxymatrine (OMT) and 5-fluorouracil (5-GU)
on a cell line of human liver cancer (HepG2) with median-effect principle in vitro. Methods: The median-effect principle and MTT method were used in the quantitative analysis of effects of the two drugs. Results: Cytotoxic activity of the individual drugs enhanced as drug concentration increased. As fa=0.41, a CI equal to 1 indicated
additivity; fa<0.41, a CI less than 1 indicated synergy; and fa>0.41, a CI greater than 1 indicated antagonism. The sequence
of administration did not influence the cytotoxic activity of the combined antitumor drugs. The ratio of drug concentration
was a factor that can influence the killing effect. Conclusion: The combined drugs interaction (CI<1) was synergistic at lower concentration and antagonistic at higher concentration. The
ratio of drug concentration is a factor that can influence the killing effect.
Biography: HE Song(1965–), male, doctor of medicine, associate professor, Chongqing Medical University, majors in gastroenterology. 相似文献