全文获取类型
收费全文 | 92347篇 |
免费 | 7591篇 |
国内免费 | 4653篇 |
专业分类
耳鼻咽喉 | 1185篇 |
儿科学 | 1196篇 |
妇产科学 | 1174篇 |
基础医学 | 11763篇 |
口腔科学 | 1753篇 |
临床医学 | 9784篇 |
内科学 | 13987篇 |
皮肤病学 | 1711篇 |
神经病学 | 4953篇 |
特种医学 | 4538篇 |
外国民族医学 | 21篇 |
外科学 | 9718篇 |
综合类 | 12206篇 |
现状与发展 | 28篇 |
一般理论 | 22篇 |
预防医学 | 6110篇 |
眼科学 | 2847篇 |
药学 | 9766篇 |
67篇 | |
中国医学 | 4073篇 |
肿瘤学 | 7689篇 |
出版年
2024年 | 191篇 |
2023年 | 1069篇 |
2022年 | 2697篇 |
2021年 | 3858篇 |
2020年 | 2658篇 |
2019年 | 2550篇 |
2018年 | 2844篇 |
2017年 | 2583篇 |
2016年 | 2792篇 |
2015年 | 4183篇 |
2014年 | 5148篇 |
2013年 | 5284篇 |
2012年 | 7755篇 |
2011年 | 8129篇 |
2010年 | 5260篇 |
2009年 | 4526篇 |
2008年 | 5750篇 |
2007年 | 5409篇 |
2006年 | 5144篇 |
2005年 | 4536篇 |
2004年 | 3529篇 |
2003年 | 3425篇 |
2002年 | 2896篇 |
2001年 | 2139篇 |
2000年 | 1757篇 |
1999年 | 1550篇 |
1998年 | 889篇 |
1997年 | 758篇 |
1996年 | 661篇 |
1995年 | 599篇 |
1994年 | 566篇 |
1993年 | 385篇 |
1992年 | 495篇 |
1991年 | 438篇 |
1990年 | 379篇 |
1989年 | 351篇 |
1988年 | 252篇 |
1987年 | 256篇 |
1986年 | 201篇 |
1985年 | 149篇 |
1984年 | 92篇 |
1983年 | 70篇 |
1982年 | 61篇 |
1981年 | 39篇 |
1980年 | 44篇 |
1979年 | 33篇 |
1978年 | 29篇 |
1975年 | 22篇 |
1974年 | 26篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Bone morphogenetic protein (BMP) was isolated from the bone matrix of swine and partially purified by means of differential precipitation and molecular sieve chromatography. The molecular weight of BMP estimated by SDS-gel electrophoresis was 19,000 dalton. Bioassay by implanting two milligrams of BMP fraction into thigh muscles of mice resulted in bone formation in 100% of the experimental animals.
相似文献
62.
63.
促甲状腺素释放激素类似物YM14673对小鼠学习记忆的影响 总被引:1,自引:0,他引:1
采用小鼠跳台法评价促甲状腺素释放激素类似物YM14673(ip1mg·kg-1)对正常成年小鼠被动回避学习记忆成绩的影响.结果表明YM14673对东莨菪碱,氯霉素和乙醇造成的小鼠记忆获得,巩固及再现障碍均有明显的改善作用. 相似文献
64.
铜绿假单胞菌全细胞脂肪酸气相色谱分析及应用 总被引:5,自引:0,他引:5
本研究用计算机控制,可程序升温的毛细管柱气相色谱(GC)仪分析48株铜绿假单胞菌标准株和临床株、部分常见假单胞菌、肠杆菌的细胞脂肪酸。结果表明:月桂烯酸(C12:1),月桂酸(C12:0)、十三碳烯酸(C13:1)、十三碳酸(C13:0)、肉豆劳动脑酸(C14:1)、十七碳稀酸(C17:1)、十七碳酸(C17:0)、硬脂酸(C18:0)和花生四烯酸(C20:4)是铜绿包菌有鉴别意义的脂肪酸,组成与 相似文献
65.
Jin Woo Kim M.D. Ho Shik Kim M.D. In Kyung Kim M.D. Mee Ran Kim M.D. Eun Young Cho B.S. Heung Kee Kim M.D. Joon Mo Lee M.D. Sung Eun Namkoong M.D. 《Gynecologic oncology》1998,69(3):230-236
Transforming growth factor-β1 (TGF-β1) is known to be a potent growth inhibitor for many cell types, including most epithelial cells. In skin keratinocytes, TGF-β1 has been shown to inhibit growth and to rapidly reduce c-mycexpression. However, the molecular mechanism of TGF-β1 action on cell growth of cervical carcinoma has not yet been elucidated. We thus assessed the effect of TGF-β1 on the growth of cervical carcinoma cell lines. Two cervical squamous carcinoma cell lines, CUMC-3 and CUMC-6, were incubated with varying concentrations of TGF-β1, and growth inhibition was evaluated with tetrazolium-based colorimetric assay. After culture in TGF-β1 for 24 h, inhibition of growth was detected in a dose-dependent manner at concentrations of 0.1–10 ng/ml in both cell lines. This effect of TGF-β1 on cultured carcinoma cells was associated with apoptotic process including oligonucleosomal ladder DNA and apoptotic body formations. Northern blot analysis revealed c-mycmRNA expression was suppressed by 10 ng/ml of TGF-β1 following 3 h of treatment in both cell lines. Western blot analysis showed that the level of p27Kip1protein was increased after TGF-β1 treatment in both cell lines. These results suggest that the mechanisms by which TGF-β1 inhibits the growth of cervical carcinoma are complex and may include effects on down-regulation of c-mycgene, and overexpression of p27Kip1protein. 相似文献
66.
Dr W. Q. Ge Z. C. Luo J. Jin Y. C. Huang S. Wang S. J. Lui 《Medical & biological engineering & computing》1998,36(1):22-26
A novel cardiokymograph system is introduced. The new system features a capacitance transducer with increased sensitivity
and can be used in multichannel measurements. The novelty of this technique is the injection of a current into the patient
coupled with the use of a capacitive displacement transducer and the possibility of multichannel monitoring. It provides for
the possibility of removing breath noise when some signal processing technique, such as adaptive filtering, is used. Further
investigation is needed to demonstrate clinical significance and pathologies. 相似文献
67.
Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver 下载免费PDF全文
Mariana D. Dabeva Seong-Gyu Hwang Srinivasa Rao G. Vasa Ethel Hurston Phyllis M. Novikoff Douglas C. Hixson Sanjeev Gupta David A. Shafritz 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(14):7356-7361
The ability to identify, isolate, and transplant progenitor cells from solid tissues would greatly facilitate the treatment of diseases currently requiring whole organ transplantation. In this study, cell fractions enriched in candidate epithelial progenitor cells from the rat pancreas were isolated and transplanted into the liver of an inbred strain of Fischer rats. Using a dipeptidyl dipeptidase IV genetic marker system to follow the fate of transplanted cells in conjunction with albumin gene expression, we provide conclusive evidence that, after transplantation to the liver, epithelial progenitor cells from the pancreas differentiate into hepatocytes, express liver-specific proteins, and become fully integrated into the liver parenchymal structure. These studies demonstrate the presence of multipotent progenitor cells in the adult pancreas and establish a role for the liver microenvironment in the terminal differentiation of epithelial cells of foregut origin. They further suggest that such progenitor cells might be useful in studies of organ repopulation following acute or chronic liver injury. 相似文献
68.
69.
Twenty-two infants of isolated ventricular septal defect with congestive heart failure were fed with lower-sodium content formula-Lonalac (Mead-Johnson) to study the clinical response of treatment for congestive heart failure. There were no significant changes of intake, urinary output, serum sodium, potassium and osmolality before, 2 days and 6 days after Lonalac feeding. The low sodium content formula may feed the infants with congestive heart failure in addition to the traditional anticongestive therapy. 相似文献
70.
补肾中药对雄激素致不孕大鼠卵巢核仁组成区蛋白的影响 总被引:4,自引:0,他引:4
观察补肾中药对雄激素致不孕大鼠卵巢核仁组成区蛋白的影响。用SD雌性大鼠幼仔,出生9d龄注射丙酸睾丸酮,制成雄激素致不孕大鼠(ASR)模型。80d龄灌服补肾中药水溶液两周。100d龄心脏灌注处死。以核仁组成区蛋白嗜银染色(AgNOR)和增殖细胞核杭原(PcNA)为指标,观察卵巢颗粒细胞、间质腺细胞的形态学变化。结果:补肾中药能够使ASR卵巢颗粒细胞增殖、卵泡发育。治疗组的AgNOR和PcNA计数明显高于模型组,而与对照组之间无显著差异。结论:补肾中药的这种作用可能是通过调节了下丘脑-垂体-卵巢性腺功能的结果,从而促使卵巢颗粒细胞发育、卵泡成熟。 相似文献