全文获取类型
收费全文 | 2217篇 |
免费 | 166篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 100篇 |
妇产科学 | 41篇 |
基础医学 | 287篇 |
口腔科学 | 65篇 |
临床医学 | 240篇 |
内科学 | 522篇 |
皮肤病学 | 46篇 |
神经病学 | 111篇 |
特种医学 | 259篇 |
外科学 | 157篇 |
综合类 | 98篇 |
一般理论 | 1篇 |
预防医学 | 203篇 |
眼科学 | 30篇 |
药学 | 113篇 |
中国医学 | 11篇 |
肿瘤学 | 94篇 |
出版年
2021年 | 16篇 |
2020年 | 13篇 |
2019年 | 22篇 |
2018年 | 21篇 |
2017年 | 21篇 |
2016年 | 20篇 |
2015年 | 34篇 |
2014年 | 64篇 |
2013年 | 98篇 |
2012年 | 72篇 |
2011年 | 79篇 |
2010年 | 62篇 |
2009年 | 82篇 |
2008年 | 60篇 |
2007年 | 96篇 |
2006年 | 74篇 |
2005年 | 93篇 |
2004年 | 68篇 |
2003年 | 60篇 |
2002年 | 63篇 |
2001年 | 61篇 |
2000年 | 56篇 |
1999年 | 55篇 |
1998年 | 93篇 |
1997年 | 64篇 |
1996年 | 72篇 |
1995年 | 53篇 |
1994年 | 66篇 |
1993年 | 55篇 |
1992年 | 36篇 |
1991年 | 31篇 |
1990年 | 44篇 |
1989年 | 63篇 |
1988年 | 57篇 |
1987年 | 52篇 |
1986年 | 41篇 |
1985年 | 43篇 |
1984年 | 24篇 |
1983年 | 25篇 |
1982年 | 27篇 |
1981年 | 30篇 |
1980年 | 17篇 |
1979年 | 23篇 |
1978年 | 21篇 |
1977年 | 25篇 |
1976年 | 14篇 |
1975年 | 17篇 |
1973年 | 8篇 |
1971年 | 9篇 |
1967年 | 6篇 |
排序方式: 共有2393条查询结果,搜索用时 15 毫秒
1.
Retrorenal colon: implications for percutaneous diskectomy 总被引:1,自引:0,他引:1
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary. 相似文献
2.
3.
Antiplaque agents delivered from toothpastes, gels, or mouthrinses can augment mechanical oral hygiene procedures to control the formation of supragingival plaque and the development of early periodontal disease. Clinically effective antiplaque agents are characterized by a combination of intrinsic antibacterial activity and good oral retention properties. The overall oral retention of an antiplaque agent is determined by the strength and rate of association of the agent with its receptor sites and the accessibility of these sites. The substantivity of an antiplaque agent and its clearance from the oral cavity are determined by the rate of dissociation of the agent from the receptor sites and the salivary composition and flow rate. Positively charged and non-charged organic molecules, metal ions, enzymes, and surface-active agents have all been considered as antiplaque agents. To exert clinical antiplaque activity, an antimicrobial agent must be formulated in a chemically compatible delivery vehicle to give optimal release and uptake to the sites of action in a biologically active form during its time of application. In principle, antiplaque activity may be enhanced by combining antimicrobial agents with broadly similar, but complementary, modes of action. Alternatively, the activity of a single agent may be increased by use of a retention aid to enhance oral substantivity. Substantial evidence exists to demonstrate the validity of the first approach. However, there are few data, as yet, to support the effectiveness of the second. The oral mucosa is the bulk retention site for all clinically proven antiplaque agents. Plaque, the pellicle-coated tooth surface, and saliva are probably all sites of biological action. A detailed understanding of the interactions between agents and the various receptor sites, and of the importance of these receptor sites to biological activity, is generally lacking. 相似文献
4.
郭永建 《福建医科大学学报》1994,(1)
采用间接ELISA检测23名肾移植受者血清巨细胞病毒(CMV)抗体,共检出18名(78%)活动性CMV感染,其中10名(44%)为原发性感染。结果证实CMV-IgE和-IgA具有较好的血清学诊断价值,优于CMV-IgM。 相似文献
5.
CA von Arnim R Spoelgen ID Peltan M Deng S Courchesne M Koker T Matsui H Kowa SF Lichtenthaler MC Irizarry BT Hyman 《The Journal of neuroscience》2006,26(39):9913-9922
The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD. 相似文献
6.
CA Schroeter† L Kaas† JJ Waterval† PM Bos‡ HAM Neumann§ 《Journal of the European Academy of Dermatology and Venereology》2007,21(9):1170-1174
AIM: The aim of this pilot study was an investigation on photodynamic therapy (PDT) whether it is a good alternative for treating periungual and subungual warts of the hands. STUDY DESIGN: Twenty patients (mean age: 30.5 years) with a total of 40 periungual and subungual warts were treated with PDT. A photosensitizer, 20%delta-aminolevulinic acid was applied on the warts. After a mean incubation time of 4.6 h (SD: 1.2), the warts were irradiated with the VersaLight for 5-30 min (15.2 +/- 4.3 min). RESULTS: After a mean of 4.5 treatments a mean clearance of 100% was achieved in 90% of the patients. One patient (5%) showed a clearance of 50% and another showed no improvement. The subungual or periungual location of the wart had no influence on the number of treatments or end result (P > 0.05). There were two recurrences during the mean follow-up period of 5.9 months (SD: 7.6). Besides mainly pain and hyperpigmentation, most treatments had no side-effects. CONCLUSION: PDT can offer a good alternative for treating periungual warts of the hands. Larger studies are indicated. 相似文献
7.
8.
9.
D. Cummins 《ISBT科学丛刊》2007,2(1):249-252
Identification errors remain the most serious and the most common type of error in blood transfusion practice. Adverse events may occur when a patient has similar or identical identifiers to another patient (a ‘doppelgänger’), is doubly registered (a ‘duplicate registration’), or when registration details are derived from two or more separate sources (a ‘hybrid registration’). Such categorization provides a valuable conceptual framework for the development of appropriate risk management strategies. Distinguishing doppelgängers from duplicate registrations is not always easy. A search of the Harefield Hospital Patient Administration System (PAS) database revealed 39 registrations that shared a forename, surname and date of birth with at least one other registration. Thirty‐seven of these cases involved a duplicate registration, one involved a hybrid registration, and one involved a doppelgänger. A national strategic tracing service is available in the UK to help resolve difficult cases. Little attention has been directed at the extent to which risk reduction strategies in this area are in conflict with political and regulatory agendas. Most notable are initiatives that aim to preserve patient confidentiality. The less that is known about an individual, the greater is the risk he will be mistaken for someone who possesses similar identifiers to himself. An important, but largely unexplored, contributor to patient identification errors is innate cognitive bias. The fundamental concept underlying all blood transfusion – unique patient identity – is inherently ambiguous and vulnerable to a range of misperceptions, particularly with regard to the twin themes of coincidence and uniqueness. A major challenge will be to develop approaches in practice and education that are suitably informed by insights gleaned from cognitive and evolutionary psychology. 相似文献