全文获取类型
收费全文 | 2007篇 |
免费 | 318篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 64篇 |
妇产科学 | 283篇 |
基础医学 | 119篇 |
口腔科学 | 28篇 |
临床医学 | 863篇 |
内科学 | 226篇 |
皮肤病学 | 51篇 |
神经病学 | 109篇 |
特种医学 | 237篇 |
外科学 | 59篇 |
综合类 | 56篇 |
一般理论 | 1篇 |
预防医学 | 90篇 |
眼科学 | 5篇 |
药学 | 67篇 |
肿瘤学 | 74篇 |
出版年
2023年 | 43篇 |
2021年 | 13篇 |
2020年 | 34篇 |
2019年 | 20篇 |
2018年 | 59篇 |
2017年 | 91篇 |
2016年 | 77篇 |
2015年 | 103篇 |
2014年 | 101篇 |
2013年 | 98篇 |
2012年 | 44篇 |
2011年 | 65篇 |
2010年 | 103篇 |
2009年 | 104篇 |
2008年 | 49篇 |
2007年 | 56篇 |
2006年 | 45篇 |
2005年 | 29篇 |
2004年 | 22篇 |
2003年 | 35篇 |
2002年 | 27篇 |
2001年 | 43篇 |
2000年 | 16篇 |
1999年 | 50篇 |
1998年 | 100篇 |
1997年 | 112篇 |
1996年 | 107篇 |
1995年 | 96篇 |
1994年 | 64篇 |
1993年 | 49篇 |
1992年 | 26篇 |
1991年 | 35篇 |
1990年 | 24篇 |
1989年 | 45篇 |
1988年 | 43篇 |
1987年 | 30篇 |
1986年 | 36篇 |
1985年 | 37篇 |
1984年 | 19篇 |
1983年 | 18篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 20篇 |
1979年 | 8篇 |
1978年 | 20篇 |
1977年 | 21篇 |
1976年 | 14篇 |
1975年 | 18篇 |
1973年 | 7篇 |
1969年 | 4篇 |
排序方式: 共有2334条查询结果,搜索用时 15 毫秒
1.
2.
D Van Neste† RM Trüeb‡ 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):578-583
BACKGROUND: Computer-assisted image analysis has been proposed for human hair growth studies. METHODS: The performances of Trichoscan, a commercially available automated system combining epiluminiscence microscopy with digital image analysis, developed for office-based hair growth measurements, have been evaluated comparatively on the same skin sites using standardized photographic equipment and calibrated processing for contrast-enhanced phototrichogram (CE-PTG) analysis. This reference method has been validated with scalp biopsies and histological examination of serial sectioning. RESULTS: Besides edge effects, hair fibres escaped the Trichoscan analysis for various reasons including, but not limited to, thickness, pigmentation, closeness and crossing. CONCLUSION: Most of these problems have been identified in the late 1980s and remain largely unsolved by the processing software that was evaluated in 2004. Therefore claims promoting the Trichoscan method for accurate hair measurements in clinical trials on scalp and body hair are not supported by the present investigation. The speed at which the analysis is performed is outweighed by the errors in signal detection. Therefore we suggest that improvements must be clearly documented before Trichoscan is established for quantified diagnostic purposes and detailed hair cycle monitoring during hair trials. 相似文献
3.
4.
The effects of aging on diencephalic (A-11, A-12, A-13, A-14) catecholamine neurons in the F344 male rat were examined with Falck-Hill?rp histofluorescence. In contrast to the age-related increase in A-12 perikaryal fluorescence intensity previously reported (Hoffman and Sladek: Neurobiol. Aging 1:27-37, '80), incertohypothalamic perikarya showed decreased (A-13) or unchanged (A-11, A-14) fluorescence intensity with age. Cell counts of fluorescent A-12 perikarya disclosed a 47% increase in the number of fluorescent A-12 neurons in 30-month-old F344 rats relative to the 3-month-old controls; numbers of A-11 and A-13 fluorescent perikarya decreased with age, but the declines were not statistically significant. It is unlikely that the age-related increase in number of fluorescent A-12 perikarya is the result of proliferation of neurons in the aged F344 rat. Rather, the greater number of fluorescent A-12 perikarya in 30-month-old F344 rats indicates that some A-12 neurons in 3-month-old F344 rats contain levels of dopamine that are subthreshold for detection with the Falck-Hill?rp fluorescence technique, whereas virtually all A-12 perikarya in 30-month-old F344 rats contain detectable quantities of dopamine. These findings suggest that diencephalic catecholamine neurons exhibit divergent changes in transmitter content and cell number that may reflect varying degrees of functional integrity during brain aging. 相似文献
5.
V Schleyer† S Radakovic-Fijan‡ S Karrer† T Zwingers§ A Tanew‡ M Landthaler† RM Szeimies† 《Journal of the European Academy of Dermatology and Venereology》2006,20(7):823-828
BACKGROUND: Based on good results in the treatment of superficial skin tumours, since the early 1990s topical photodynamic therapy with aminolaevulinic acid (ALA PDT) has been used for disseminated, inflammatory dermatoses including psoriasis. However, there is still a lack of well-documented trials. OBJECTIVE: A prospective randomized, double-blind phase I/II intrapatient comparison study was conducted in 12 patients to investigate whether topical ALA PDT is an effective treatment for chronic plaque-type psoriasis. METHODS: In each patient three psoriatic plaques were randomly treated with a light dose of 20 J/cm(2) and 0.1%, 1% and 5% ALA, respectively. Treatment was conducted twice a week until complete clearance or for a maximum of 12 irradiations. Therapeutic efficacy was assessed by weekly determination of the psoriasis severity index (PSI). RESULTS: The mean percentage improvement was 37.5%, 45.6% and 51.2% in the 0.1%, 1% and 5% ALA-treated groups, respectively. Irradiation had to be interrupted several times because of severe burning and pain sensation. CONCLUSION: Topical ALA PDT did not prove to be an appropriate treatment option for plaque-type psoriasis due to disappointing clinical efficacy, the time-consuming treatment procedure and its unfavourable adverse event profile. 相似文献
6.
7.
8.
Nerve-cell grafting in Parkinson's disease 总被引:4,自引:0,他引:4
The successful utilization of fetal nerve-cell grafts as therapeutic tools in animal models of neurodegenerative disease has prompted the first clinical attempts in parkinsonian patients in at least three countries. The extensive scientific data in rodents coupled with the first successful fetal neural grafts in monkeys with experimental parkinsonism suggest that consideration might now be given to clinical applications. Attention is also directed to the various types of donor cells that might be utilized in clinical trials for the treatment of parkinsonism, including potential benefits, risks, and limitations associated with each type of donor material. This review highlights major developments in this field as they relate to basic principles of neural grafting and discusses potential applications in humans. 相似文献
9.
10.
Fred R. Kohn Gregory J. Landkamer Norman E. Sladek 《Immunopharmacology and immunotoxicology》1987,9(2):163-176
The ex vivo sensitivity of murine multipotent (CFU-GEMM) and committed (CFU-Mk, CFU-GM, BFU-E and CFU-E) hematopoietic progenitor cells to mafosfamide was quantified with and without concurrent exposure to cyanamide, an inhibitor of aldehyde dehydrogenase activity. In the absence of cyanamide, CFU-GEMM, CFU-Mk and CFU-GM were approximately equisensitive to mafosfamide while the erythroid progenitors were more sensitive to the drug. Cyanamide potentiated the cytotoxicity of mafosfamide toward CFU-GEMM and CFU-Mk, but not toward CFU-GM, BFU-E and CFU-E. Cellular aldehyde dehydrogenases are known to catalyze the oxidation of 4-hydroxycyclophos-phamide/aldophosphamide, the major intermediate in cyclophosphamide and mafosfamide activation, to the relatively nontoxic acid, carboxyphosphamide. Thus, our findings indicate that 1) murine CFU-GEMM contain the relevant aldehyde dehydrogenase activity, and 2) the relevant aldehyde dehydrogenase activity is retained upon differentiation to progenitors committed to the megakaryocytoid lineage, but lost upon differentiation to progenitors committed to the granulocytoid/monocytoid and erythroid lineages. The relative insensitivity of CFU-GM to mafosfamide is apparently due to a cellular determinant that influences their sensitivity to all cross-Unking agents since CFU-GM were found to be relatively insensitive to non-oxazaphosphorine cross-linking agents as well. 相似文献