首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   55695篇
  免费   5837篇
  国内免费   2520篇
耳鼻咽喉   895篇
儿科学   1205篇
妇产科学   402篇
基础医学   6755篇
口腔科学   7725篇
临床医学   4946篇
内科学   5631篇
皮肤病学   282篇
神经病学   1835篇
特种医学   2703篇
外国民族医学   25篇
外科学   12021篇
综合类   8335篇
现状与发展   8篇
预防医学   2707篇
眼科学   561篇
药学   3033篇
  23篇
中国医学   1886篇
肿瘤学   3074篇
  2024年   50篇
  2023年   787篇
  2022年   1062篇
  2021年   2008篇
  2020年   2075篇
  2019年   1889篇
  2018年   1855篇
  2017年   1909篇
  2016年   1849篇
  2015年   2096篇
  2014年   3513篇
  2013年   4672篇
  2012年   3004篇
  2011年   3457篇
  2010年   2959篇
  2009年   2890篇
  2008年   2806篇
  2007年   2886篇
  2006年   2585篇
  2005年   2563篇
  2004年   2223篇
  2003年   1933篇
  2002年   1659篇
  2001年   1448篇
  2000年   1227篇
  1999年   1063篇
  1998年   823篇
  1997年   816篇
  1996年   738篇
  1995年   613篇
  1994年   585篇
  1993年   464篇
  1992年   455篇
  1991年   374篇
  1990年   305篇
  1989年   267篇
  1988年   234篇
  1987年   186篇
  1986年   177篇
  1985年   234篇
  1984年   187篇
  1983年   172篇
  1982年   171篇
  1981年   152篇
  1980年   137篇
  1979年   116篇
  1978年   117篇
  1977年   82篇
  1976年   70篇
  1975年   41篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
赵曦  黄泽清 《现代肿瘤医学》2020,(20):3484-3489
目的:研究七氟烷预处理对大鼠骨髓间充质干细胞(MSCs)在缺氧复氧环境下的作用和机制初探。方法:分离培养SD大鼠骨髓间充质干细胞,通过流式细胞仪和诱导分化培养鉴定其免疫表型和分化潜能。细胞随机分为3组:组1空白对照组;组2缺氧复氧组(缺氧24 h,复氧24 h);组3七氟烷预处理组(2%七氟烷预处理2 h后,缺氧24 h,复氧24 h)。处理后收集各组细胞,用流式细胞仪测定其凋亡率,线粒体膜电位变化及细胞周期。Western blot测定细胞外调节蛋白激酶(ERK)的蛋白表达。结果:与组2相比,组3 MSCs凋亡率明显下降,处于S期细胞增多,细胞增殖能力增强。Western blot结果显示:与组2相比,组3磷酸化ERK蛋白表达上升。结论:七氟烷预处理能提高缺氧复氧环境下骨髓间充质干细胞存活率,降低MSCs凋亡数量,并能增强MSCs的增殖能力,这一机制与七氟烷促进MSCs细胞p-ERK蛋白表达相关。  相似文献   
22.
目的研究多元化教学模式在骨科临床教学中的开展效果及价值。方法选取2018年1月-2019年7月在我院骨科实习的94名医学生,采用随机数字表法进行分组,为47名参照组学生采用传统教学方法,为47名学生采用多元化教学模式,对比二组学生的考核成绩与学生满意度。结果实验组学生的理论知识评分、实际操作评分、总成绩均高于参照组,实验组学生对教学方法的满意度(97.87%)也明显高于参照组(85.11%),经统计P<0.05,组间比较差异具有统计学分析价值。结论在骨科临床教学中,开展多元化教学模式,对提升教学效果与学生满意度均有积极帮助。  相似文献   
23.
24.
虫类药因其药性的猛烈,药物功效对症,成为治疗乳腺癌骨转移的常用药。相较于其他中药,虫类药对各类恶性肿瘤有较好的疗效,但在运用的同时还需注意,虫类药的毒性以及其对脏腑,尤其是肝脏的损伤,需动态关注患者各项生命体征变化,药用时间不宜过长,应严格遵守药物禁忌、配伍等规则,并要求临床医师辨证准确,密切观察患者病情变化。同时,虫类药的更多药物作用机制、临床方案的优化等,需进一步研究探讨。  相似文献   
25.
目的:观察清脑汤治疗H型高血压的临床疗效及对同型半胱氨酸、血脂的影响。方法:选择2016年10月至2018年12月在本院就诊的168例H型高血压患者为研究对象,按照随机数字表法分为对照组和治疗组,每组各84例,对照组采用非洛地平缓释片治疗,每次5 mg,每日清晨口服,治疗组采用中药清脑汤治疗,日1剂,水煎服,分2次温服。两组均以7 d为1个疗程,均连续治疗4个疗程。观察两组患者治疗前后血压、血脂水平和心功能。结果:治疗后,治疗组日间收缩压、夜间收缩压、日间舒张压、夜间舒张压较对照组明显降低,差异有统计学意义(P<0.05);治疗后,治疗组同型半胱氨酸(homocystein,Hcy)、总胆固醇(total cholesterol,TC)、高密度脂蛋白(high density lipoprotein-C,HDL-C)及三酰甘油(triacylglycerol,TG)水平与对照组比较明显降低,差异有统计学意义(P<0.05);对照组不良反应发生率为16.67%,治疗组不良反应发生率为5.95%,两组不良反应发生率比较,差异具有统计学意义(P<0.05);治疗组每搏输出量(stroke volume,SV)、左心室射血分数(left ventricular ejection fraction,LVEF)高于对照组(P<0.05),左心室舒张末期内径(left ventricular end-systolic dimension,LVEDD)低于对照组(P<0.05);对照组有效率为73.81%,治疗组有效率为90.48%,两组有效率比较,差异具有统计学意义(P<0.05)。结论:清脑汤可以提高H型高血压患者的临床疗效,降低同型半胱氨酸及血脂的浓度。  相似文献   
26.
Chondrosarcoma is the second most common form of bone cancer and is characterized by its ability to produce an extracellular matrix of the cartilage. High-grade chondrosarcoma is highly aggressive and can metastasize to other parts of the body. Chondrosarcoma is resistant to both conventional chemotherapy and radiotherapy; hence, the current main treatment is still surgical resection. Doxorubicin (Dox) has been shown to significantly improve patient survival compared with untreated chondrosarcoma. However, for patients with metastasis, surgical resection alone can hardly treat them. In addition, drug resistance is one of the leading causes of death in patients with chondrosarcoma. Secreted proteins can mediate cell-cell interactions in the cancer microenvironment, which may be associated with the development of drug resistance. In the present study, chondrosarcoma cells were treated with Dox, the conditioned medium was then collected and changes in secreted proteins were analyzed using the antibody array. Results showed that the Dox-treated group had the highest secretion of basic fibroblast growth factor (bFGF), indicating the effect of bFGF on Dox sensitivity in chondrosarcoma. Furthermore, lentiviral-mediated knockdown and treatment of exogenous recombinant protein were employed to further investigate the effect of bFGF on Dox resistance. Results demonstrated that bFGF can promote the expression of X-ray repair cross-complementing protein 5 (XRCC5), leading to Dox resistance. Secreted bFGF is likely to be detected in serum, in addition to being a biomarker for predicting Dox resistance, the combination of Dox and bFGF/XRCC5 blockers may be a new therapeutic strategy to improve the efficacy of Dox in future.  相似文献   
27.
28.
29.

Purpose

Anorexia nervosa (AN) is a chronic and life-threatening eating disorder that can have a considerable negative impact on the growing skeleton. We hypothesized that the long-term impact on bone health may persist even after normalization of body weight.

Methods

41 females (mean age 21.2 ± 2.9 years) with a history of adolescent-onset AN attended a follow-up bone health assessment at 5 years (T5, n?=?28) or 10 years (T10, n?=?13) after their first AN-related hospital admission. Assessment included dual-energy x-ray absorptiometry measurements of the total body, lumbar spine, and proximal femur, peripheral quantitative computed tomography at the radius and tibia, anthropometric measurements, serum biochemistry, fracture history, and a patient questionnaire.

Results

A recovery in body weight and BMI was seen for both the T5 and T10 cohorts (BMI at intake 16.6, BMI at T5-T10 21.2-21.3). Dual-energy x-ray absorptiometry body composition indicated a recovery of fat mass and lean tissue mass. Total BMD was unaffected, but reductions were seen at the femoral neck and arms. Peripheral quantitative computed tomography showed reduced trabecular and cortical bone in the radius, and cortical thinning in the tibia. AN patients showed a statistically significant reduction in measures of radiographic bone health at follow up, although not to a degree that necessitated clinical intervention. Serum insulin-like growth factor 1 was also positively correlated with total BMD and BMC measures. While fracture risk was not increased, a subset of participants (8%) showed multiple (>4) fractures.

Conclusion

A longitudinal study of adolescent AN showed persisting negative effects on bone health.  相似文献   
30.
《肿瘤防治研究》2020,(7):517-523
Objective To investigate the correlation of rib 99mTc-MDP foci on whole-body bone scan with clinical variables and rib metastases in nasopharyngeal carcinoma(NPC) patients, and to screen the risk factors of rib metastases. Methods We retrospectively reviewed 312 NPC patients with rib 99mTc-MDP foci on wholebody bone scan. Chi-square test and logistic regression were performed to evaluate the correlation between clinical variables and rib metastases. Results In all 312 NPC patients, rib metastases were associated with T stage, skull base bone invasion, other bone metastasis, number of rib foci, lateral localization on rib and foci type (P<0.01), and the risk factors of rib metastasis included skull base bone invasion, other bone metastases, lateral localization on rib and foci type (P<0.05). In 176 patients with pure rib foci, rib metastases were closely related to T stage, skull base bone invasion, other bone metastasis, number of rib foci and lateral localization on rib (P<0.05), while only lobar distribution (P=0.029) was the effective risk factor. In 198 patients with single rib focus, rib metastases were affected by skull base bone invasion and foci type (P<0.01), while only foci type (P=0.000) was the effective risk factor. In all 566 rib foci, uptake level and localization on rib were the effective risk factors of rib metastases(P<0.01). Conclusion In NPC patients with rib foci on whole body bone scan, the effective risk factors of rib metastases include skull base bone invasion, other bone metastases, lateral localization on rib, foci type, uptake level and anterior and posterior localization on rib. Follow up should be the main way for the pure rib foci on unilateral ribs. For multiples rib foci on bilateral ribs or single rib focus combined with other bones foci, additional image modalities should be required to exclude bone metastasis. © 2020, CHINA RESEARCH ON PREVENTION AND TREATMENT. All rights reserved.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号