全文获取类型
收费全文 | 763篇 |
免费 | 54篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 33篇 |
妇产科学 | 14篇 |
基础医学 | 135篇 |
口腔科学 | 30篇 |
临床医学 | 65篇 |
内科学 | 139篇 |
皮肤病学 | 53篇 |
神经病学 | 56篇 |
特种医学 | 24篇 |
外科学 | 69篇 |
综合类 | 5篇 |
预防医学 | 79篇 |
眼科学 | 9篇 |
药学 | 50篇 |
肿瘤学 | 51篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 26篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 18篇 |
2015年 | 37篇 |
2014年 | 44篇 |
2013年 | 48篇 |
2012年 | 59篇 |
2011年 | 71篇 |
2010年 | 27篇 |
2009年 | 32篇 |
2008年 | 45篇 |
2007年 | 55篇 |
2006年 | 44篇 |
2005年 | 46篇 |
2004年 | 42篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有819条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
A clinical, microbiologic, and radiographic study of deep caries lesions after incomplete caries removal. 总被引:3,自引:0,他引:3
Marisa Maltz Elenara F de Oliveira Vania Fontanella Rafael Bianchi 《Quintessence international, dental digest》2002,33(2):151-159
OBJECTIVE: Clinical, radiographic, and microbiologic changes in deep caries lesions were assessed after incomplete carious dentin removal and tooth sealing. METHOD AND MATERIALS: Thirty-two teeth with deep caries lesions were studied. Treatment consisted of incomplete excavation of the demineralized dentin, application of calcium hydroxide, and sealing for a 6- to 7-month period. The color and consistency of the dentin were clinically assessed. Differences in radiographic density were assessed by digital image subtraction. Microbiologic samples were obtained from the demineralized dentin before the temporary sealing and after the experimental period. The samples were cultivated on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar, and Rogosa selective Lactobacillus agar. RESULTS: Two cases were lost during the study; one presented pulpal necrosis. In the other case, there was pulpal exposure during removal of provisional sealing. In all teeth, the initial demineralized dentin was soft and wet; one lesion was yellow, 21 were light brown, and eight were dark brown. After treatment, the dentin was dry, and 80.00% of specimens were hard, 16.67% were leathery, and 3.33% remained soft. The dentin was light brown in five teeth and dark brown in 25. There was a statistically significant mean difference in radiographic density (pixel intensity), 88.77 +/- 7.02 in the control areas and 94.66 +/- 6.75 in the test areas. The counts of anaerobic and aerobic bacteria, lactobacilli, and Streptococci mutans had decreased significantly by the end of treatment. CONCLUSION: Incomplete removal of carious dentin and subsequent tooth sealing resulted in the arrest of the lesions, suggesting that complete dentinal caries lesion removal is not essential to the control of caries lesions. 相似文献
5.
Davide Gatti Francesca Colapietro Elena Fracassi Elisabetta Sartori Franco Antoniazzi Vania Braga Maurizio Rossini Silvano Adami 《Journal of clinical densitometry》2003,6(2):173-177
In patients with osteogenesis imperfecta (OI), a disease characterized by abnormal bone fragility, bone mineral density (BMD) was found to be relatively preserved. Quantitative computed tomography (QCT) is the only available method for directly measuring in vivo both volumetric density and the cross-sectional area. Here we report the data from dual-energy X-ray absorptiometry DXA (spine and hip) and peripheral (pQCT) (ultradistal and proximal radius) measurement of 27 adult patients affected by OI, mostly of type I, compared with a group of healthy persons. In the patients with OI, areal BMD values at both femoral neck and lumbar spine were considerably lower than in control subjects (-32 and -36%, respectively; p<0.001 for body weight and height adjusted values). pQCT volumetric density at the ultradistal radius was 19% lower than in control subjects and this difference rose to 32% for purely cancellous bone tissue. The whole bone cross-sectional area of ultradistal radius, as measured by pQCT, was superimposable to normal. At the proximal radius, both cross-sectional area and cortical area, together with Bending Breaking Resistance Index (BBRI), were significantly lower in OI (-23; -22; -32% respectively; p<0.001 for body weight and height adjusted values), but cortical volumetric density was even slightly higher in the OI group than in control subjects. In conclusion, it appears that the most obvious defect in adults with OI is the inability to acquire an adequate thickness of the cortices of long bone and to achieve or maintain normal trabecular density. 相似文献
6.
Ulisses Xavier da Silva Neto Ivaldo Gomes de Moraes Vania Portela Ditzel Westphalen Renato Menezes Everdan Carneiro Luiz Fernando Fariniuk 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(2):e53-e57
OBJECTIVE: The aim of this study was to measure leakage of 4 resin-based sealers. STUDY DESIGN: Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi. RESULTS: Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05). CONCLUSION: It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ. 相似文献
7.
Rapid production of Candida albicans chlamydospores in liquid media under various incubation conditions. 总被引:1,自引:0,他引:1
Zavalza-Stiker Alicia Ortiz-Saldivar Blanca García-Hernández Mariana Castillo-Casanova Magdalena Bonifaz Alexandro 《Nippon Ishinkin Gakkai Zasshi》2006,47(3):231-234
The production of chlamydospores is a diagnostic tool used to identify Candida albicans; these structures also represent a model for morphogenetic research. The time required to produce them with standard methods is 48-72 hours in rice meal agar and tensoactive agents. This time can be shorted using liquid media such as cornmeal broth (CMB) and dairy supplements. Five media were tested: CMB plus 1% Tween-80, CMB plus 5% milk, CMB plus 5% milk serum, milk serum, and milk serum plus 1% Tween-80, under different incubation conditions: at 28 degrees C and 37 degrees C in a metabolic bath stirring at 150 rpm, and at 28 degrees C in a culture stove. The reading time points were established at 8 and 16 hours. The best results were obtained at 16 hours with CMB plus 5% milk under incubation at 28 degrees C and stirring at 150 rpm. The next most efficient methods were CMB plus 5% milk serum and CMB plus 1% Tween-80, under the same incubation conditions. The other media were ineffective in producing chlamydospores. The absence of stirring at 28 degrees C prevented the formation of chlamydospores within the set time points, and incubation at 37 degrees C decreased their production. This paper reports that the time to form C. albicans chlamydospores can be reduced. 相似文献
8.
Paolo Sportoletti Beatrice Del Papa Mariangela De Ioanni Lorenzo Moretti Elisabetta Bonifacio Vania Lanterna Alain Bell Katia Fettucciari Eugenia Carnevali Tiziana Zei Franca Falzetti Massimo F Martelli Antonio Tabilio Mauro Di Ianni 《Biology of blood and marrow transplantation》2006,12(12):1250-1260
T-cell homeostasis is regulated by several molecules; among these, interleukin (IL)-7 plays an essential role in the survival and homeostatic proliferation of peripheral naive T cells. In a previous study, we investigated whether human mesenchymal stromal cells (MSCs) could be engineered with the IL-7 gene to produce functional level of this cytokine. In the present study, we analyzed the impact of different quantities of IL-7 produced by MSCs on the survival and proliferation of a negative immunoselected naive (CD3(+)/CD45RA(+)) T-cell population. Co-cultivation of peripheral naive T cells with MSCs producing low (16 pg/mL) or high (1000 pg/mL) IL-7 levels or in the presence of exogenous IL-7 (0.01 ng/mL and 100 ng/mL) maintained the CD3(+)/CD45RA(+) naive T-cell phenotype. Chemokine receptor CCR7(+) expression was also maintained among this T-cell population. Naive T-cell molecular characteristics were maintained as assessed by the Vbeta spectratyping complexity score, which showed the maintenance of a broad T-cell repertoire. No Th1 or Th2 differentiation was observed, as assessed by interferon-gamma or IL-4 accumulation. In contrast, only MSCs producing high amounts of IL-7 caused increased activation (CD25 31.2% +/- 12% vs 10% +/- 3.5%; P < .05), proliferation (CD71 17.8+/-7% vs 9.3%+/-3, P < .05), apoptosis (assessed by annexin V: 18.6% +/- 5% vs 14.9% +/- 2.6%; P > .05), and the phase S cell cycle (15% vs 6.9%, P > .05). Exogenous IL-7 exhibited no significant effect. In conclusion, we demonstrated that IL-7 produced by MSCs has a dose-independent effect on naive T-cell survival while exerting a dose-dependent effect on activation/proliferation. Due to the continuous production of IL-7 by engineered cells, our system is more efficacious than exogenous IL-7. 相似文献
9.
Ferrer I Kapfhammer JP Hindelang C Kemp S Troffer-Charlier N Broccoli V Callyzot N Mooyer P Selhorst J Vreken P Wanders RJ Mandel JL Pujol A 《Human molecular genetics》2005,14(23):3565-3577
ATP-binding cassette (ABC) transporters facilitate unidirectional translocation of chemically diverse substances, ranging from peptides to lipids, across cell or organelle membranes. In peroxisomes, a subfamily of four ABC transporters (ABCD1 to ABCD4) has been related to fatty acid transport, because patients with mutations in ABCD1 (ALD gene) suffer from X-linked adrenoleukodystrophy (X-ALD), a disease characterized by an accumulation of very-long-chain fatty acids (VLCFAs). Inactivation in the mouse of the abcd1 gene leads to a late-onset neurodegenerative condition, comparable to the late-onset form of X-ALD [Pujol, A., Hindelang, C., Callizot, N., Bartsch, U., Schachner, M. and Mandel, J.L. (2002) Late onset neurological phenotype of the X-ALD gene inactivation in mice: a mouse model for adrenomyeloneuropathy. Hum. Mol. Genet., 11, 499-505.]. In the present work, we have generated and characterized a mouse deficient for abcd2, the closest paralog to abcd1. The main pathological feature in abcd2-/- mice is a late-onset cerebellar and sensory ataxia, with loss of cerebellar Purkinje cells and dorsal root ganglia cell degeneration, correlating with accumulation of VLCFAs in the latter cellular population. Axonal degeneration was present in dorsal and ventral columns in spinal cord. We have identified mitochondrial, Golgi and endoplasmic reticulum damage as the underlying pathological mechanism, thus providing evidence of a disturbed organelle cross-talk, which may be at the origin of the pathological cascade. 相似文献
10.
Xiao FX Yotova V Zietkiewicz E Lovell A Gehl D Bourgeois S Moreau C Spanaki C Plaitakis A Moisan JP Labuda D 《European journal of human genetics : EJHG》2004,12(4):301-311
Within Europe, classical genetic markers, nuclear autosomal and Y-chromosome DNA polymorphisms display an east-west frequency gradient. This has been taken as evidence for the westward migration of Neolithic farmers from the Middle East. In contrast, most studies of mtDNA variation in Europe and the Middle East have not revealed clinal distributions. Here we report an analysis of dys44 haplotypes, consisting of 35 polymorphisms on an 8 kb segment of the dystrophin gene on Xp21, in a sample of 1203 Eurasian chromosomes. Our results do not show a significant genetic structure in Europe, though when Middle Eastern samples are included a very low but significant genetic structure, rooted in Middle Eastern heterogeneity, is observed. This structure was not correlated to either geography or language, indicating that neither of these factors are a barrier to gene flow within Europe and/or the Middle East. Spatial autocorrelation analysis did not show clinal variation from the Middle East to Europe, though an underlying and ancient east-west cline across the Eurasian continent was detected. Clines provide a strong signal of ancient major population migration(s), and we suggest that the observed cline likely resulted from an ancient, bifurcating migration out of Africa that influenced the colonizing of Europe, Asia and the Americas. Our study reveals that, in addition to settlements from the Near East, Europe has been influenced by other major population movements, such as expansion(s) from Asia, as well as by recent gene flow from within Europe and the Middle East. 相似文献