全文获取类型
收费全文 | 381673篇 |
免费 | 36456篇 |
国内免费 | 25514篇 |
专业分类
耳鼻咽喉 | 2880篇 |
儿科学 | 4919篇 |
妇产科学 | 4211篇 |
基础医学 | 42006篇 |
口腔科学 | 6256篇 |
临床医学 | 53951篇 |
内科学 | 51596篇 |
皮肤病学 | 4158篇 |
神经病学 | 18601篇 |
特种医学 | 13892篇 |
外国民族医学 | 224篇 |
外科学 | 33981篇 |
综合类 | 70774篇 |
现状与发展 | 86篇 |
一般理论 | 31篇 |
预防医学 | 27974篇 |
眼科学 | 10854篇 |
药学 | 41015篇 |
508篇 | |
中国医学 | 25164篇 |
肿瘤学 | 30562篇 |
出版年
2025年 | 76篇 |
2024年 | 4697篇 |
2023年 | 7282篇 |
2022年 | 15034篇 |
2021年 | 18757篇 |
2020年 | 15288篇 |
2019年 | 11961篇 |
2018年 | 12284篇 |
2017年 | 11824篇 |
2016年 | 10963篇 |
2015年 | 16937篇 |
2014年 | 21052篇 |
2013年 | 19115篇 |
2012年 | 28422篇 |
2011年 | 31884篇 |
2010年 | 21504篇 |
2009年 | 17515篇 |
2008年 | 21395篇 |
2007年 | 21118篇 |
2006年 | 20140篇 |
2005年 | 19226篇 |
2004年 | 12702篇 |
2003年 | 12231篇 |
2002年 | 10004篇 |
2001年 | 8531篇 |
2000年 | 8316篇 |
1999年 | 8388篇 |
1998年 | 5301篇 |
1997年 | 5093篇 |
1996年 | 3957篇 |
1995年 | 3716篇 |
1994年 | 3135篇 |
1993年 | 2026篇 |
1992年 | 2426篇 |
1991年 | 2127篇 |
1990年 | 1793篇 |
1989年 | 1556篇 |
1988年 | 1283篇 |
1987年 | 1183篇 |
1986年 | 955篇 |
1985年 | 676篇 |
1984年 | 370篇 |
1983年 | 271篇 |
1982年 | 142篇 |
1981年 | 169篇 |
1980年 | 118篇 |
1979年 | 154篇 |
1978年 | 73篇 |
1977年 | 53篇 |
1974年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Qiuji Shao Qiang Li Qiaowei Wu Tianxiao Li Li Li Kaitao Chang 《The British journal of radiology》2021,94(1118)
Objective:In-stent restenosis (ISR) after stenting for intracranial stenosis is a significant issue. This study aimed to evaluate the usefulness of the 3D T1-SPACE technique in the follow-up of patients after stent implantation.Methods:Fifteen patients with intracranial arterial stenosis were prospectively enrolled 6–8 months after stenting. Digital subtraction angiography (DSA) and 3D T1-SPACE imaging were performed to evaluate the degree of stenosis and the enhancement of the vessel wall. Bland–Altman plots were used to assess the agreement between the two imaging methods, and the Pearson correlation coefficient was calculated as a measure of the linear correlation.Results:Eight Enterprise stents and seven Wingspan stents were used in 15 patients. The follow-up DSA after 6–8 months showed that the degree of stenosis was 40% (range, 30–72%), and ISR occurred in 4 of 15 (26.7%) lesions. The degree of stenosis assessed using the 3D T1-SPACE imaging technique was 35% (range, 30–75%). All four patients with ISR demonstrated significant enhancement. The Pearson correlation coefficient between the two methods was 0.959 (p < 0.05), and the Bland–Altman plot showed that all data points were within the consistency limits ( ± 1.96 s).Conclusion:As a non-invasive imaging modality, 3D T1-SPACE showed great consistency with DSA in measuring the degree of stenosis after intracranial stenting. It may be used as an optional method for detecting ISR.Advances in knowledge:This study evaluated the usefulness of 3D T1-SPACE technique in the follow-up of patients after stent implantation, which could be used as an optional and non-invasive method in detection of in-stent restenosis. 相似文献
32.
目的 研究补肺活血法治疗慢性阻塞性肺疾病缓解期的临床疗效和对肺功能的影响.方法 将125例患者随机分为治疗组85例和对照组40例,两组均经缓解期常规基础治疗,治疗组加用中药汤剂口服.两组均以2周为1个疗程,连续治疗4个疗程后统计疗效.结果 治疗组总有效率为94.1%,对照组总有效率为90.0%,两组相比,P<0.05;两组的主要症状和体征均改善,但治疗组对咳嗽、咳痰、喘促、气短以及肺部罗音等症状体征改善均优于对照组(P<0.01);治疗组的肺功能的改善优于对照组(P<0.05);治疗组的发病次数明显少于对照组(P<0.05).结论 补肺活血法能有效改善慢性阻塞性肺疾病缓解期患者的临床症状、体征、肺功能,减少患者发病次数,并提高其生活质量. 相似文献
33.
目的 总结貌似多发性硬化的皮层下梗死和白质脑病的常染色体显性遗传性脑动脉病(CADASIL)的临床特点.方法 报告1例经基因检查和周围神经活检确诊为CADASIL的临床资料.结果 患者腓肠神经活检可见有髓神经纤维密度轻度减少,电镜下可见神经束膜小动脉中层平滑肌细胞外大量颗粒性电子致密嗜锇颗粒物质(GOM)沉积.基因检测显示Notch3基因4号外显子Cys117Arg突变.结论 为避免CADASIL的漏诊及误诊,凡遇青年反复脑卒中发作,又无高血压、糖尿病等常见的血管病危险因素,虽无偏头痛病史,亦应注意追问家族史并做基因检测和周围神经活检. 相似文献
34.
目的探讨中老年冠心病患者动脉粥样硬化性肾动脉狭窄的患病率和危险因素.方法对339例冠脉造影诊断为冠心病的中老年患者,同时进行选择性双侧肾动脉造影.结果肾动脉狭窄的发生率为37.2%(126/339).肾动脉狭窄组年龄、高血压病、吸烟者的比率均高于非肾动脉狭窄组(P<0.001、<0.03、<0.02),肾动脉狭窄患病率随病变程度加重有逐渐增加的趋势(x2趋势=4.17,P<0.0001).多因素回归分析中,年龄、高血压、吸烟和冠心病多支病变为肾动脉狭窄的独立危险因素(P<0.05).结论中老年冠心病患者,尤其是高龄、高血压、吸烟、多支病变的患者应常规行选择性肾动脉造影. 相似文献
35.
增生性瘢痕是皮肤遭遇创伤后,因细胞外基质异常沉积、过度纤维化造成的皮肤病理现象。对于瘢痕诊断、临床疗效判定及比较研究,临床上使用的客观且可靠的瘢痕评判方法具有关键作用。我们就增生性瘢痕的评估、测量方式及工具的研究进展进行综述。 相似文献
36.
Feng Li Wenqiang Guo Li Wu Tianjiao Zhu Qianqun Gu Dehai Li Qian Che 《Archives of pharmacal research》2018,41(1):30-34
Three new diketopiperazine derivatives (DKPs), saroclazines A–C (1–3) along with three known DKPs (4–6) were isolated from mangrove-derived fungi Sarocladium kiliense HDN11-84. Saroclazines A–B (1 and 2) possessed a free amide structure, which was first found in sulfur-containing aromatic DKPs. Their structures were elucidated by NMR, HRESIMS and X-ray. The cytotoxic activity of new compounds (1–3) was tested against HeLa cell lines, among which compound 2 showed an IC50 value of 4.2 µM. 相似文献
37.
Diethylstilbestrol impaired oogenesis of yellow catfish juveniles through disrupting hypothalamic–pituitary–gonadal axis and germ cell development 下载免费PDF全文
Yaqin Wang Yingwen Li Qiliang Chen Zhihao Liu 《Journal of applied toxicology : JAT》2018,38(3):308-317
Diethylstilbestrol (DES), a non‐steroidal estrogen, has been found to cause altered germ cell development and disordered ovarian development in fish females. However, the mechanisms that might be involved are poorly understood. In this study, female juveniles of yellow catfish (Pelteobagrus fulvidraco) (120 days post‐hatching) were exposed to two doses (10 and 100 ng l?1) of DES for 28 days. After the endpoint of exposure, decreased ovary weight and gonadosomatic index, as well as various ovarian impairments were observed in response to DES. Besides, DES elevated the mRNA levels of vitellogenin 1 (vtg 1) and estrogen receptor 1 (esr 1) in liver and decreased 17β‐estradiol level in plasma. Correspondingly, suppressed mRNA levels of the key genes in the hypothalamic–pituitary–gonadal axis (such as cyp19a1b, gnrh‐II, fshβ and lhβ in brain and fshr, lhr and cyp19a1a in ovary) after DES exposure were also observed. The declined level of plasma 17β‐estradiol and altered gene expressions of genes in the hypothalamic–pituitary–gonadal axis were thus supposed to be closely related to the disrupted oogenesis in DES‐treated fish. Analyses further demonstrated that, higher concentration of DES elevated the expression ratio of bax/bcl‐2, indicating the enhanced apoptosis occurred in ovary. Moreover, DES upregulated the expressions of genes involved in proliferation (cyclin d1 and pcna), meiotic entry (cyp26a1 and scp3) and meiotic maintenance (dmc1), resulting in arrested oogenesis in catfish. The present study greatly extended our understanding on the mechanisms underlying of reproductive toxicity of DES on fish oogenesis. 相似文献
38.
39.
Proton pump inhibitors are associated with accelerated development of cirrhosis,hepatic decompensation and hepatocellular carcinoma in noncirrhotic patients with chronic hepatitis C infection: results from ERCHIVES 下载免费PDF全文
D. K. Li P. Yan A‐B. Abou‐Samra R. T. Chung A. A. Butt 《Alimentary pharmacology & therapeutics》2018,47(2):246-258
40.