全文获取类型
收费全文 | 1223篇 |
免费 | 104篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 77篇 |
妇产科学 | 20篇 |
基础医学 | 147篇 |
口腔科学 | 94篇 |
临床医学 | 109篇 |
内科学 | 290篇 |
皮肤病学 | 32篇 |
神经病学 | 52篇 |
特种医学 | 96篇 |
外科学 | 166篇 |
综合类 | 52篇 |
预防医学 | 41篇 |
眼科学 | 8篇 |
药学 | 60篇 |
中国医学 | 4篇 |
肿瘤学 | 40篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 30篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 31篇 |
2017年 | 25篇 |
2016年 | 29篇 |
2015年 | 28篇 |
2014年 | 46篇 |
2013年 | 60篇 |
2012年 | 71篇 |
2011年 | 64篇 |
2010年 | 55篇 |
2009年 | 62篇 |
2008年 | 55篇 |
2007年 | 59篇 |
2006年 | 52篇 |
2005年 | 41篇 |
2004年 | 37篇 |
2003年 | 40篇 |
2002年 | 43篇 |
2001年 | 23篇 |
2000年 | 17篇 |
1999年 | 21篇 |
1998年 | 31篇 |
1997年 | 45篇 |
1996年 | 35篇 |
1995年 | 22篇 |
1994年 | 23篇 |
1993年 | 23篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 28篇 |
1988年 | 17篇 |
1987年 | 15篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 11篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有1328条查询结果,搜索用时 31 毫秒
1.
V Aerra M Kuduvalli AN Moloto AK Srinivasan AD Grayson BM Fabri AY Oo 《Journal of cardiothoracic surgery》2006,1(1):6-5
Background
Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. 相似文献2.
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章. 相似文献
3.
4.
5.
O6-Alkylguanine--DNA alkyltransferase (AGT) is a protein which removes the promutagenic O6-alkylguanine lesion induced in DNA by alkylating agents. Our results demonstrate that freshly isolated organoids from reduction mammoplasty specimens contain significant levels of AGT activity. AGT activity in breast epithelial cells shows interindividual variation. Constitutive levels of AGT activity remain unchanged during short-term serum-free culture of breast epithelial cells inside three-dimensional rat-tail collagen gel matrix. In the present study, we optimized conditions for depleting AGT activity in human breast epithelial cells cultured in three-dimensional collagen gel matrix using O6-methylguanine and O6-benzylguanine which are substrates for AGT. AGT activity was efficiently inactivated by exposure of cells to O6-methylguanine or O6-benzylguanine. Inactivation with O6-benzylguanine was more rapid, of greater magnitude and consistency and occurred at lower concentrations than with O6-methylguanine. Near-complete inactivation (> 99.5%) of AGT activity was reproducibly achieved with 50 microM O6-benzylguanine. In contrast, 500 microM O6-methylguanine was needed to obtain a maximal effect and this reduced AGT activity by only 53-93% of control. Within 30 min of adding the free base, 50 microM O6-benzylguanine depleted 95% of the levels of AGT compared to 30% inhibition with 500 microM O6-methylguanine. The profile for restoration of AGT activity was different following a 24 h incubation and subsequent removal of each of the guanine derivatives. AGT activity levels remained undetectable for at least 2 days after removal of 50 microM O6-benzylguanine from the medium and recovered to only 53% of control values after an additional 3 days. AGT activity levels remained undetectable for at least 2 days after removal of 50 microM O6-benzylguanine from the medium and recovered to only 53% of control values after an additional 3 days. In contrast, following removal of 500 microM O6-methylguanine, the activity was restored from its nadir of 16% of control values reaching pretreatment levels after 5 days. These results suggest that treatment with O6-benzylguanine may be used to modulate the incidence of transforming mutations in cultured human breast epithelial cells treated with chemical carcinogens which give rise to O6-alkylguanine adducts. 相似文献
6.
R Zachariah AD Harries MP Spielmann V Arendt D Nchingula R Mwenda O Courtielle P Kirpach B Mwale FML Salaniponi 《Malawi medical journal : the journal of Medical Association of Malawi》2002,14(2):10-12
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi. 相似文献
7.
CHERYL K. ROTH AD RNC BONNIE RILEY RN CCRN SUSAN M. COHEN DSN RN 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1992,21(4):310-311
Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms. 相似文献
8.
9.
10.