全文获取类型
收费全文 | 1121篇 |
免费 | 71篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 25篇 |
妇产科学 | 17篇 |
基础医学 | 159篇 |
口腔科学 | 16篇 |
临床医学 | 199篇 |
内科学 | 159篇 |
皮肤病学 | 9篇 |
神经病学 | 78篇 |
特种医学 | 30篇 |
外科学 | 102篇 |
综合类 | 2篇 |
一般理论 | 1篇 |
预防医学 | 141篇 |
眼科学 | 9篇 |
药学 | 98篇 |
中国医学 | 2篇 |
肿瘤学 | 138篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 32篇 |
2021年 | 47篇 |
2020年 | 35篇 |
2019年 | 48篇 |
2018年 | 31篇 |
2017年 | 29篇 |
2016年 | 31篇 |
2015年 | 29篇 |
2014年 | 48篇 |
2013年 | 64篇 |
2012年 | 84篇 |
2011年 | 84篇 |
2010年 | 45篇 |
2009年 | 57篇 |
2008年 | 70篇 |
2007年 | 64篇 |
2006年 | 60篇 |
2005年 | 56篇 |
2004年 | 43篇 |
2003年 | 30篇 |
2002年 | 28篇 |
2001年 | 11篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有1192条查询结果,搜索用时 15 毫秒
71.
72.
73.
Incorporation of an ERA attachment for obturator framework design: a clinical report 总被引:5,自引:0,他引:5
Sigurgeirsdottir E Minsely GE Rothenberger SL 《The Journal of prosthetic dentistry》2002,87(5):477-480
Swinglock framework designs have been used to retain obturators for some time. One of the problems with Swinglock designs has been loss of retention due to wear of the metal latch assembly. This clinical report describes the incorporation of an ERA attachment as the latch assembly of a Swinglock framework for an obturator. The premise behind this design was that wear would be at the expense of the nylon retention male component, which is easily interchangeable, rather than the metal component of the assembly. The life of the latch assembly, framework, and prosthesis would thereby be prolonged. 相似文献
74.
Krona C Ejeskär K Abel F Kogner P Bjelke J Björk E Sjöberg RM Martinsson T 《Oncogene》2003,22(15):2343-2351
Deletion of a part of the short arm of chromosome 1 is one of the most common chromosomal rearrangements observed in neuroblastoma (NBL) tumors and it is associated with a poor prognosis. No NBL tumor suppressor gene has yet been identified in the region. Our shortest region of overlap of deletions, ranging from marker D1S80 to D1S244, was shown to partly overlap a 500 kb region that was homozygously deleted in a NBL cell line. We have screened seven genes known to reside in or very close to this overlap consensus region, UBE4B/UFD2, KIF1B, DFFA, PGD, CORT, PEX14, and ICAT, for coding mutations in NBL tumor DNA. A few deviations from the reference sequences were identified; most interestingly being a splice site mutation that was detected in UBE4B/UFD2 in a stage 3 NBL with a fatal outcome. This mutation was neither present in the patients constitutional DNA nor in any of 192 control chromosomes analysed. Also, the expression of UBE4B/UFD2 was markedly diminished in the high-stage/poor-outcome tumors as compared to the low-stage/favorable-outcome tumors. Overall, the number of amino-acid changes in the genes of the region was low, which shows that mutations in these genes are rare events in NBL development. Given the data presented here, UBE4B/UFD2 stands out as the strongest candidate NBL tumor suppressor gene in the region at this stage. 相似文献
75.
Breast cancer and specific types of oral contraceptives: a large Norwegian cohort study 总被引:4,自引:0,他引:4
Dumeaux V Alsaker E Lund E 《International journal of cancer. Journal international du cancer》2003,105(6):844-850
The aim of our study was to examine the risk of breast cancer according to specific types of estrogens and progestagens in oral contraceptives (OCs) based on the prospective Norwegian Women and Cancer study (NOWAC). Between 1991-97 women aged 30-70 years were drawn at random from the central person register and mailed an invitation and a questionnaire. Women (102,443) were enrolled with follow-up information collected throughout 1999 by linkage with national registries of cancer, mortality and emigration based on the unique national identification number. Among the 96,362 women included in the present analysis 851 invasive breast cancer were diagnosed. The adjusted risk of breast cancer increased with 25% for ever use of OCs and the risk increased with increasing duration of use (test for trend: p = 0.007). No association between time since last use and breast cancer risk was found after stratification on duration of use. Positive trend was still found for total duration of use among women who used OCs more than 5 years ago. Second generation of OCs had an increased risk with increasing duration of use. Classifying progestagens according to chemical groups, the relative risk increased significantly with increasing cumulative dose of levonorgestrel progestagen. It was difficult to conclude for the other groups due to lack of power. In a multivariate analysis the cumulative dose for all progestagen groups were non-significant, although we observed a significant increased risk with increasing milligram-months of estrogen exposure (p = 0.002). In conclusion, the increased risk of breast cancer related with OC formulations could be due mostly to estrogen component. 相似文献
76.
77.
78.
Accuracy of Determining Nodal Negativity in Colorectal Cancer on the Basis of the Number of Nodes Retrieved on Resection 总被引:7,自引:0,他引:7
Joseph NE Sigurdson ER Hanlon AL Wang H Mayer RJ MacDonald JS Catalano PJ Haller DG 《Annals of surgical oncology》2003,10(3):213-218
Background: Correct determination of nodal status is pivotal to accurate staging and predicting survival.Methods: This is a secondary analysis of INT0089, an intergroup trial of adjuvant chemotherapy for high-risk stage II and III colon cancer. A subset of patients was studied who underwent right or left hemicolectomy and from whom at least 10 lymph nodes were examined. A mathematical model was created to estimate the probability of a true negative result on the basis of the number of nodes examined. The number of nodes needed to predict nodal negativity with 85%, 50%, and 25% probability on the basis of tumor stage was calculated.Results: In this analysis, 1585 patients were studied. The average number of nodes removed at surgery was comparable between treatment groups at 18.5 (median of 16 in all groups). With this model, when 18 nodes are removed at resection, there is a <25% probability of true node negativity in T1/T2 tumors, whereas <10 nodes need to be examined in T3 and T4 tumors to achieve the same probability.Conclusions: Tumor stage and the number of nodes retrieved at resection influence the accuracy of determining nodal status in colon cancer. Most patients are understaged. Underestimating nodal stage may influence decisions regarding adjuvant therapy, as well as overall prognosis. 相似文献
79.
Canlon B Erichsen S Nemlander E Chen M Hossain A Celsi G Ceccatelli S 《The European journal of neuroscience》2003,17(10):2035-2041
Prenatal exposure to excessive glucocorticoids alters the programming of the metabolic and endocrine balance of various organs, including the nervous system. In the present study, prenatal glucocorticoid treatment was shown to increase the susceptibility of the inner ear to acoustic noise trauma in adult life. Acute auditory brainstem response thresholds were not different between the age-matched groups. However, when measured at 48 h and 4 weeks postexposure, the dexamethasone (DEX)-treated rats showed little or no recovery from the trauma. In contrast, normal rats showed a significant amount of recovery by 48 h postexposure and continued to show further recovery over 4 weeks. In addition, acoustic trauma resulted in a massive outer hair cell loss in the DEX rats compared to minor loss in the normal rats. To determine whether oxidative stress plays a role in the recovery phase of acoustic trauma, the free radical scavenger PBN (100 mg/kg) was administered before, during and several times after noise exposure. PBN treatment significantly reduced the physiological and morphological cochlear differences which were observed between DEX and control rats after acoustic trauma. These data support the hypothesis that alterations in the intrauterine environment may modify the developmental programme of the cochlea, inducing dysfunction later in adult life. Excessive prenatal exposure to dexamethasone decreased the potential for recovery of the cochlea to oxidative stress induced by acoustic trauma; this decreased recovery potential can be counteracted by treatment with antioxidants. 相似文献
80.
Gustafsson E Andsberg G Darsalia V Mohapel P Mandel RJ Kirik D Lindvall O Kokaia Z 《The European journal of neuroscience》2003,17(12):2667-2678
To explore the role of brain-derived neurotrophic factor for survival and generation of striatal neurons after stroke, recombinant adeno-associated viral vectors carrying brain-derived neurotrophic factor or green fluorescent protein genes were injected into right rat substantia nigra 4-5 weeks prior to 30 min ipsilateral of middle cerebral artery occlusion. The brain-derived neurotrophic factor-recombinant adeno-associated viral transduction markedly increased the production of brain-derived neurotrophic factor protein by nigral cells. Brain-derived neurotrophic factor was transported anterogradely to the striatum and released in biologically active form, as revealed by the hypertrophic response of striatal neuropeptide Y-positive interneurons. Animals transduced with brain-derived neurotrophic factor-recombinant adeno-associated virus also exhibited abnormalities in body posture and movements, including tilted body to the right, choreiform movements of left forelimb and head, and spontaneous, so-called 'barrel' rotation along their long axis. The continuous delivery of brain-derived neurotrophic factor had no effect on the survival of striatal projection neurons after stroke, but exaggerated the loss of cholinergic, and parvalbumin- and neuropeptide Y-positive, gamma-aminobutyric acid-ergic interneurons. The high brain-derived neurotrophic factor levels in the animals subjected to stroke also gave rise to an increased number of striatal cells expressing doublecortin, a marker for migrating neuroblasts, and cells double-labelled with the mitotic marker, 5-bromo-2'-deoxyuridine-5'monophosphate, and early neuronal (Hu) or striatal neuronal (Meis2) markers. Our findings indicate that long-term anterograde delivery of high levels of brain-derived neurotrophic factor increases the vulnerability of striatal interneurons to stroke-induced damage. Concomitantly, brain-derived neurotrophic factor potentiates the stroke-induced neurogenic response, at least at early stages. 相似文献