全文获取类型
收费全文 | 2030篇 |
免费 | 204篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 36篇 |
妇产科学 | 27篇 |
基础医学 | 287篇 |
口腔科学 | 18篇 |
临床医学 | 214篇 |
内科学 | 348篇 |
皮肤病学 | 36篇 |
神经病学 | 92篇 |
特种医学 | 182篇 |
外科学 | 258篇 |
综合类 | 58篇 |
一般理论 | 1篇 |
预防医学 | 248篇 |
眼科学 | 157篇 |
药学 | 99篇 |
中国医学 | 3篇 |
肿瘤学 | 176篇 |
出版年
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 14篇 |
2019年 | 29篇 |
2018年 | 52篇 |
2017年 | 36篇 |
2016年 | 43篇 |
2015年 | 45篇 |
2014年 | 69篇 |
2013年 | 99篇 |
2012年 | 116篇 |
2011年 | 113篇 |
2010年 | 56篇 |
2009年 | 64篇 |
2008年 | 115篇 |
2007年 | 103篇 |
2006年 | 107篇 |
2005年 | 110篇 |
2004年 | 98篇 |
2003年 | 114篇 |
2002年 | 103篇 |
2001年 | 45篇 |
2000年 | 26篇 |
1999年 | 34篇 |
1998年 | 43篇 |
1997年 | 23篇 |
1996年 | 20篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 21篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1988年 | 16篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 14篇 |
1980年 | 14篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 15篇 |
1975年 | 13篇 |
1974年 | 12篇 |
1948年 | 11篇 |
1947年 | 13篇 |
1946年 | 16篇 |
1945年 | 14篇 |
排序方式: 共有2242条查询结果,搜索用时 234 毫秒
81.
实时灰阶超声造影和螺旋CT诊断肝肿瘤的比较研究 总被引:26,自引:2,他引:26
目的比较实时超声造影和螺旋CT显示肝肿瘤血流信号的特点.方法对29例肝肿瘤(原发性肝癌16例,转移性肝癌2例,血管瘤6例和肝局灶性结节增生5例)分别进行超声造影和CT检查.结果超声造影显示肝恶性肿瘤的整体型、血管瘤的周边型及局灶性结节增生的中央型出现率显著高于其他病变(P<0.01).CT示恶性肿瘤中94.4%(17/18) 动脉期强化、门脉期低密度;血管瘤中83.3%(5/6)呈结节状强化;肝局灶性结节增生动脉期均明显强化.超声造影和CT鉴别肝肿瘤的能力无显著差异.结论超声造影和CT都能敏感地显示不同肝肿瘤的血供特征. 相似文献
82.
Lyle S Christofidou-Solomidou M Liu Y Elder DE Albelda S Cotsarelis G 《The journal of investigative dermatology. Symposium proceedings / the Society for Investigative Dermatology, Inc. [and] European Society for Dermatological Research》1999,4(3):296-301
Stem cells are vital for the homeostasis of self-renewing tissues and their manipulation may have wide ranging applications, including gene therapy, wound repair, and tissue transplantation. Although rodent hair follicle stem cells have been localized to the follicle bulge, the location of human hair follicle stem cells is less clear, and their characterization has been hampered by a lack of cellular markers for the bulge area. We demonstrate that the C8/144B monoclonal antibody, originally raised against a CD8 peptide sequence, immunostains the human hair follicle bulge. We show that this antibody recognizes cytokeratin 15 (K15) in keratinocytes, and that K15-positive bulge cells possess a stem cell phenotype characterized by their slowly cycling nature, proliferation at the onset of new hair follicle growth, and high level of beta1 integrin expression. These results localize human hair follicle stem cells to the bulge and suggest that K15 is preferentially expressed in epithelial stem cells. 相似文献
83.
目的:评价螺旋CT在诊断肺动脉栓塞中的作用。方法:16例肺动脉栓塞患者行螺旋CT肺动脉造影 (SCTA)检查,层厚3mm,扫描时间0.8s,对比剂注射速度3.5ml/s,总量100ml,扫描延迟时间15s。结果:16例 共644支,其中134支肺动脉及分支显示了栓塞,占20.8%。228支肺段肺动脉中,有56支显示肺动脉栓塞,占分 析肺动脉支的24.5%。204支亚段肺动脉中37支显示肺动脉栓塞,占分析肺动脉支15.4%。肺动脉栓塞的CT形 态:①直接征象为不同程度的肺动脉分支内充盈缺损。中心型充盈缺损17支,偏心型充盈缺损44支,附壁血栓型 34支,完全阻塞型39支。②间接征象胸膜下肺梗死灶,内乳动脉一侧增粗,肺纹理稀少,胸水,肺动脉高压。结论: 螺旋CT肺动脉造影是诊断肺动脉栓塞的快速、有效、无创伤的诊断方法。 相似文献
84.
Hayes RD Bennett C Dennerstein L Gurrin L Fairley C 《The journal of sexual medicine》2007,4(2):286-295
IntroductionStudies that address sensitive topics, such as female sexual difficulty and dysfunction, often achieve poor response rates that can bias results. Factors that affect response rates to studies in this area are not well characterized.AimTo model the response rate in studies investigating the prevalence of female sexual difficulty and dysfunction.MethodsDatabases were searched for English-language, prevalence studies using the search terms: sexual difficulties/dysfunction, woman/women/female, prevalence, and cross-sectional. Studies that did not report response rates or were clinic-based were excluded. A multiple linear regression model was constructed.Main Outcome MeasuresPublished response rates.ResultsA total of 1,380 publications were identified, and 54 of these met our inclusion criteria. Our model explained 58% of the variance in response rates of studies investigating the prevalence of difficulty with desire, arousal, orgasm, or sexual pain (R2 = 0.581, P = 0.027). This model was based on study design variables, study year, location, and the reported prevalence of each type of sexual difficulty. More recent studies (β = −1.05, P = 0.037) and studies that only included women over 50 years of age (β = −31.11, P = 0.007) had lower response rates. The use of face-to-face interviews was associated with a higher response rate (β = 20.51, P = 0.036). Studies that did not include questions regarding desire difficulties achieved higher response rates than those that did include questions on desire difficulty (β = 23.70, P = 0.034).ConclusionResponse rates in prevalence studies addressing female sexual difficulty and dysfunction are frequently low and have decreased by an average of just over 1% per anum since the late 60s. Participation may improve by conducting interviews in person. Studies that investigate a broad range of ages may be less representative of older women, due to a poorer response in older age groups. Lower response rates in studies that investigate desire difficulty suggest that sexual desire is a particularly sensitive topic. Hayes RD, Bennett C, Dennerstein L, Gurrin L, and Fairley C. Modeling response rates in surveys of female sexual difficulty and dysfunction. 相似文献
85.
Saptarshi Mukerji Lyle Moncur Brendon Sanders Alex Currie Alistair Watson Karen Leeman 《The Australasian medical journal》2013,6(7):367-370
Tuberculosis (TB) of the cervix is a rare disease, especially in developed countries. We presented a patient with primary TB of the cervix with no concurrent immune deficiency or HIV infections. The case clinically mimicked carcinoma of the cervix. Difficulties in diagnosis have been discussed. Given the recent increase in migration patterns including travel from TB endemic areas, an abnormal-looking cervix should be regarded with a degree of suspicion for TB. 相似文献
86.
Michelle M. Perfect Gary R. Elkins Teresa Lyle‐Lahroud Jennie R. Posey 《Stress and health》2010,26(1):61-74
Several studies have suggested that stress and sleep may be related to diabetic disease progression. Cortisol is one physiological indicator of stress that has been well validated in previous research. The primary objectives of the present study were (1) to examine the experiences of stress among patients diagnosed with diabetes and (2) to evaluate the quality of sleep among these participants. Participants (mean age = 34.99 years) were 20 adolescents and adults with Diabetes Mellitus; 13 had Type 1 and 17 were female. Primary measures included actigraphy, the Pittsburgh Sleep Quality Index (PSQI), salivary cortisol and the Perceived Stress Scale (PSS). Participants reported a moderate amount of stress (mean PSS scores = 20.2), slept an average of 6.51 h and exhibited at least one clinical indicator of sleep disturbance. Objectively measured total sleep time was associated with awakening cortisol (r = 0.62, p = 0.004) and PSQI Global scores (r = ‐0.51, p = 0.021). Awakening cortisol and PSS scores were not associated with PSQI Global scores, but were related to specific self‐reported sleep disturbances. Given the interacting physiological pathways of stress and sleep, both of which were evident in this small sample, these variables warrant further study. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
87.
88.
89.
Michael Thrall MD Klint Kjeldahl CT H. Evin Gulbahce MD Stefan E. Pambuccian MD 《Cancer cytopathology》2007,111(4):217-223
BACKGROUND.
In addition to the reporting of atypical glandular cells (AGC) and adenocarcinoma (ADCA), the 2001 Bethesda System requires the reporting of benign‐appearing endometrial cells in women aged >40 years (BAEMC). In this study, the authors evaluated the contribution of each of these reporting categories to the sensitivity and specificity of a liquid‐based Papanicolaou test for endometrial carcinoma or hyperplasia.METHODS.
Over the 3‐year study period, in the setting of a large, multihospital health care system, the authors analyzed the results from liquid‐based Papanicolaou tests that were performed within the 6 months that preceded a histologic diagnosis of endometrial carcinoma or hyperplasia and that were reported according to the 2001 Bethesda System.RESULTS.
Two hundred seventy‐two women had a histologic diagnosis of endometrial hyperplasia (n = 199) or malignancy (n = 73) within 6 months after a Papanicolaou test. In total, 188,594 Papanicolaou tests (91,385 from women aged >40 years) were interpreted during the study period and resulted in 3810 diagnoses of BAEMC, 326 diagnoses of AGC, and 30 diagnoses of ADCA. Only 28 of 73 women (38.4%) with endometrial carcinoma had cytologically AGC or ADCA reported on a previous Papanicolaou test. The reporting of BAEMC increased this sensitivity by only 5.5% (4 additional tests) but decreased the specificity of the Papanicolaou test for endometrial malignancy from 99.8% to 96%. For endometrial hyperplasias, the sensitivity of the Papanicolaou test was even lower (39 of 198 tests; 19.7%), but BAEMC represented the majority of endometrial‐type cells reported (36 of 39 tests).CONCLUSIONS.
The reporting of BAEMC led to an only marginal increase in sensitivity that had to be weighed against the significant loss in specificity of the Papanicolaou test for endometrial neoplasia. Cancer (Cancer Cytopathol) 2007. © 2007 American Cancer Society. 相似文献90.
Jennifer Stone Lyle C Gurrin Graham B Byrnes Christopher J Schroen Susan A Treloar Emma J D Padilla Gillian S Dite Melissa C Southey Vanessa M Hayes John L Hopper 《Cancer epidemiology, biomarkers & prevention》2007,16(7):1479-1484
BACKGROUND: Mammographic density, the light/white radiographic appearance on a mammogram that represents connective and epithelial tissue, is a strong risk factor for breast cancer which seems to be highly heritable. Little is known about its genetic determinants. METHODS: We studied 457 women from 207 sisterhoods (104 monozygotic twins, 182 dizygotic twins, and 171 singletons). Percentage mammographic density (PMD) as well as dense area and nondense area were calculated using a computer-assisted method. We measured six single nucleotide polymorphisms from six candidate genes (COMT, HSD3B1, IGFBP3, HER2, XPD, and XRCC3). Associations between genotypes and mammographic measures were tested (a) cross-sectionally using a multivariate normal model fitted using FISHER that allowed separate correlations for monozygotic, dizygotic, and nontwin pairs and (b) within sister pairs using paired t tests. RESULTS: Cross-sectionally, each additional copy of the HSD3B1 Asn(367)Thr variant allele was associated with lower PMD (-3.47% per allele; SE = 1.65; P = 0.035). Within-pair regression estimates confirmed this association. There was no evidence for an association between the mammographic density measures and any of the other variants studied. CONCLUSION: We have replicated an association between a variant in the HSD3B1 gene and PMD, which suggests that HSD3B1 may be genetic determinant of mammographic density. 相似文献