全文获取类型
收费全文 | 415791篇 |
免费 | 23595篇 |
国内免费 | 17123篇 |
专业分类
耳鼻咽喉 | 3193篇 |
儿科学 | 9378篇 |
妇产科学 | 6199篇 |
基础医学 | 44496篇 |
口腔科学 | 5603篇 |
临床医学 | 46884篇 |
内科学 | 65909篇 |
皮肤病学 | 3214篇 |
神经病学 | 29360篇 |
特种医学 | 17788篇 |
外国民族医学 | 144篇 |
外科学 | 51559篇 |
综合类 | 42921篇 |
现状与发展 | 61篇 |
一般理论 | 23篇 |
预防医学 | 33559篇 |
眼科学 | 10011篇 |
药学 | 34983篇 |
233篇 | |
中国医学 | 14630篇 |
肿瘤学 | 36361篇 |
出版年
2024年 | 764篇 |
2023年 | 3857篇 |
2022年 | 9927篇 |
2021年 | 12552篇 |
2020年 | 9484篇 |
2019年 | 8318篇 |
2018年 | 29852篇 |
2017年 | 24625篇 |
2016年 | 26217篇 |
2015年 | 12186篇 |
2014年 | 14794篇 |
2013年 | 12902篇 |
2012年 | 24859篇 |
2011年 | 40662篇 |
2010年 | 30597篇 |
2009年 | 20952篇 |
2008年 | 31900篇 |
2007年 | 34137篇 |
2006年 | 13312篇 |
2005年 | 14687篇 |
2004年 | 11289篇 |
2003年 | 11865篇 |
2002年 | 8728篇 |
2001年 | 5908篇 |
2000年 | 6277篇 |
1999年 | 6254篇 |
1998年 | 3933篇 |
1997年 | 3902篇 |
1996年 | 3048篇 |
1995年 | 2815篇 |
1994年 | 2340篇 |
1993年 | 1485篇 |
1992年 | 1993篇 |
1991年 | 1715篇 |
1990年 | 1442篇 |
1989年 | 1199篇 |
1988年 | 1087篇 |
1987年 | 952篇 |
1986年 | 762篇 |
1985年 | 575篇 |
1984年 | 366篇 |
1983年 | 268篇 |
1982年 | 179篇 |
1981年 | 160篇 |
1980年 | 155篇 |
1979年 | 151篇 |
1978年 | 60篇 |
1975年 | 68篇 |
1974年 | 78篇 |
1938年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
A new micelle system formed from methoxy (polyethylene glycol)-b-poly (5-benzyloxy-trimethylene carbonate; MePEG-b-PBTMC 5000-b-4800) was investigated as a delivery system for the hydrophobic anti-cancer agent, ellipticine. The ellipticine was loaded into the MePEG-b-PBTMC micelles with a loading efficiency of 95% using a high-pressure extrusion technique. The ellipticine-loaded micelles have a spherical morphology and an average diameter of 96 nm. The anti-cancer activity of ellipticine was confirmed to be retained following formulation in the MePEG-b-PBTMC micelles. The extent of protein adsorption to the MePEG-b-PBTMC micelles was investigated by transmission electron microscopy, dynamic light scattering and gel filtration chromatography. Overall, the amount of protein both loosely and tightly associated with the micelles was found to be minimal and insignificant. The partitioning properties of ellipticine between an aqueous medium containing protein and the MePEG-b-PBTMC micelles were examined over a range of protein concentrations. Under physiologically relevant conditions, it was found that 61% of the drug remained within the micelle fraction while 39% was in the protein-containing aqueous phase. In addition, the in vitro drug release profile of ellipticine from the micelles was fit using a modified Higuchi model and found to be accelerated in the presence of protein. These studies demonstrate that although there are no significant interactions between micelle and protein, the properties of the micelle as a delivery vehicle may be strongly influenced by protein-drug interactions. 相似文献
32.
33.
Pneumocephalus is a very rare complication of video-assisted thoracoscopic surgery (VATS). A 66-year-old man developed pneumocephalus secondary to thoracoscopic excision of a neurogenic tumor in the posterior mediastinum. Pneumocephalus was diagnosed by brain computed tomography. Neurosurgical intervention was performed after conservative therapy had failed. The patient's condition had resolved without any neurologic sequelae 2 years later. When a patient has a relatively large amount of chest tube drainage and neurologic symptoms after VATS, the possibility of pneumocephalus due to cerebrospinal fluid leakage must be considered. 相似文献
34.
35.
Henry Cisneros 《AIDS and behavior》2007,11(2):7-8
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference. 相似文献
36.
37.
The authors reviewed the radiographic manifestations of 17 cases of parosteal osteosarcoma, with pathologic correlation in 15. There were two types of parosteal osteosarcoma radiologically. The majority of cases were type I with uniformly dense masses which had regular borders. They often adhered to the cortex and showed no evidence of soft-tissue invasion which correlated with low-grade pathologic malignancy and a relatively benign clinical course. Type II involved the bone, soft-tissue and the medullary cavity. These lesions were poorly differentiated and frequently accompanied by metastatic lesions.
相似文献
38.
39.
40.