全文获取类型
收费全文 | 2460篇 |
免费 | 185篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 103篇 |
妇产科学 | 70篇 |
基础医学 | 295篇 |
口腔科学 | 46篇 |
临床医学 | 352篇 |
内科学 | 563篇 |
皮肤病学 | 40篇 |
神经病学 | 136篇 |
特种医学 | 214篇 |
外科学 | 240篇 |
综合类 | 64篇 |
预防医学 | 196篇 |
眼科学 | 14篇 |
药学 | 165篇 |
中国医学 | 16篇 |
肿瘤学 | 152篇 |
出版年
2023年 | 30篇 |
2022年 | 26篇 |
2021年 | 54篇 |
2020年 | 28篇 |
2019年 | 44篇 |
2018年 | 71篇 |
2017年 | 52篇 |
2016年 | 60篇 |
2015年 | 57篇 |
2014年 | 99篇 |
2013年 | 129篇 |
2012年 | 134篇 |
2011年 | 124篇 |
2010年 | 104篇 |
2009年 | 102篇 |
2008年 | 107篇 |
2007年 | 96篇 |
2006年 | 109篇 |
2005年 | 117篇 |
2004年 | 82篇 |
2003年 | 80篇 |
2002年 | 65篇 |
2001年 | 60篇 |
2000年 | 53篇 |
1999年 | 51篇 |
1998年 | 52篇 |
1997年 | 48篇 |
1996年 | 55篇 |
1995年 | 46篇 |
1994年 | 29篇 |
1993年 | 35篇 |
1992年 | 38篇 |
1991年 | 39篇 |
1990年 | 28篇 |
1989年 | 44篇 |
1988年 | 37篇 |
1987年 | 32篇 |
1986年 | 19篇 |
1985年 | 33篇 |
1984年 | 22篇 |
1983年 | 16篇 |
1982年 | 23篇 |
1981年 | 13篇 |
1980年 | 20篇 |
1978年 | 13篇 |
1977年 | 19篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 9篇 |
排序方式: 共有2683条查询结果,搜索用时 15 毫秒
1.
2.
3.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
4.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence. 相似文献
5.
A case-referent study of lung cancer, occupational exposures and smoking. II. Role of asbestos exposure 总被引:6,自引:0,他引:6
H Kjuus R Skjaerven S Lang?rd J T Lien T Aamodt 《Scandinavian journal of work, environment & health》1986,12(3):203-209
In a hospital-based case-referent study of 176 incident lung cancer cases, ascertained during a five-year period from two county hospitals, the role of asbestos exposure and smoking has been studied. Information on asbestos exposure was obtained from personal interviews, and allocated to four exposure categories, according to the intensity and duration of the exposure. Twenty-five percent of the cases and 10% of the referents had been moderately to heavily exposed to asbestos during their working career. A statistically significant trend in risk ratio related to the degree of exposure was observed, with a more than fourfold risk among the heavily exposed. The strongest association was found between asbestos exposure and small cell carcinoma, and the weakest association between asbestos exposure and adenocarcinoma. Very high risk ratios were observed among asbestos-exposed subjects who were heavy smokers, and the interaction observed between asbestos and smoking conformed more closely to a multiplicative model than to an additive one. The results suggest that the observed association between lung cancer and occupational exposures in this study was, to a large extent, due to asbestos exposure. Information on such exposure was missing in 90% of the medical records of these patients. 相似文献
6.
Huang Guo-Shu MD Chang Wei-Chou MD Lee Herng-Sheng MD † Taylor John A. M. DC DACBR ‡ Cheng Tiang-Yeu MD § Chen Cheng-Yu MD 《Dermatologic surgery》2005,31(6):717-719
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis. 相似文献
7.
8.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献
9.
The purpose of this pilot study was to observe both relaxed and deep breathing patterns in a convenience sample to determine the incidence of normal versus faulty patterns of respiration. These observations were then combined with respondent answers to a survey on pain history to determine if there is any correlation between faulty breathing and musculo-skeletal pain patterns. If such a correlation can be made, then we propose that clinicians working with chronic pain patients may have improved outcomes if they address and correct faulty breathing patterns. Based on this study, it is suggested to include the evaluation and treatment of faulty respiration in the rehabilitation of chronic musculo-skeletal conditions, most notably cervical pain. 相似文献
10.
I A Cliffe E L Lien H L Mansell K E Steiner R S Todd A C White R M Black 《Journal of medicinal chemistry》1992,35(7):1169-1175
A series of pyrimido[1,2-a]indoles were synthesized and studied for their hypoglycemic activity following oral administration at a standard dose of 100 mg/kg to fed rats. The effect of 10-alkoxyalkyl, 10-alkyl, 10-aryl, and 3,3-dialkyl substitution on the activity of 10-hydroxypyrimido[1,2-a]indoles was investigated. Relative potencies of a number of the most active compounds were defined by three-point dose-response studies. The most potent compounds were those with either 3,3-dimethyl substituents, compounds 21, 22, and 38, or 3,3-spirocyclohexane substituents, compounds 39 and 49. 10-Aminopyrimido[1,2-a]indoles were in general less active than the 10-hydroxy analogues, and potency was further decreased by derivatizing the 10-amino group. The most potent 10-amino derivatives were 57 and 58. 相似文献