全文获取类型
收费全文 | 24937篇 |
免费 | 2627篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 237篇 |
儿科学 | 861篇 |
妇产科学 | 807篇 |
基础医学 | 3449篇 |
口腔科学 | 442篇 |
临床医学 | 2865篇 |
内科学 | 4931篇 |
皮肤病学 | 232篇 |
神经病学 | 2035篇 |
特种医学 | 864篇 |
外科学 | 3371篇 |
综合类 | 652篇 |
一般理论 | 49篇 |
预防医学 | 3127篇 |
眼科学 | 384篇 |
药学 | 1813篇 |
中国医学 | 22篇 |
肿瘤学 | 1447篇 |
出版年
2023年 | 155篇 |
2022年 | 190篇 |
2021年 | 476篇 |
2020年 | 318篇 |
2019年 | 456篇 |
2018年 | 516篇 |
2017年 | 409篇 |
2016年 | 389篇 |
2015年 | 439篇 |
2014年 | 613篇 |
2013年 | 982篇 |
2012年 | 1267篇 |
2011年 | 1360篇 |
2010年 | 737篇 |
2009年 | 665篇 |
2008年 | 1104篇 |
2007年 | 1136篇 |
2006年 | 1048篇 |
2005年 | 1050篇 |
2004年 | 958篇 |
2003年 | 965篇 |
2002年 | 871篇 |
2001年 | 741篇 |
2000年 | 792篇 |
1999年 | 663篇 |
1998年 | 326篇 |
1997年 | 252篇 |
1996年 | 277篇 |
1995年 | 239篇 |
1994年 | 202篇 |
1993年 | 207篇 |
1992年 | 542篇 |
1991年 | 579篇 |
1990年 | 538篇 |
1989年 | 506篇 |
1988年 | 430篇 |
1987年 | 475篇 |
1986年 | 428篇 |
1985年 | 402篇 |
1984年 | 349篇 |
1983年 | 280篇 |
1982年 | 179篇 |
1981年 | 170篇 |
1980年 | 148篇 |
1979年 | 239篇 |
1978年 | 176篇 |
1977年 | 174篇 |
1974年 | 203篇 |
1973年 | 186篇 |
1970年 | 148篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
W. Demark-Wahnefried J. McClelland M. K. Campbell K. Hoben J. Lashley C. Graves B. Motsinger B. K. Rimer 《Journal of the National Medical Association》1998,90(4):197-202
African Americans are at increased risk for cancer and represent an important target population for programs such as Healthy People 2000, the Cancer Information Service (CIS), and the 5 a Day for Better Health Initiative. Yet, awareness of such programs among rural blacks is unknown. This study assessed awareness of these programs and determined related knowledge and beliefs among rural African Americans. It was undertaken as part of the baseline survey for the Black Churches United for Better Health project, a National Cancer Institute-funded initiative. A minority of respondents (n = 3737) demonstrated name recognition of Healthy People 2000 (23.4%), the CIS (42.4%), and the 5 a Day Program (40.7%). Far fewer (7.4%) were able to correctly identify the recommended daily number of servings of fruits and vegetables. Reported family history of cancer was associated with a greater tendency believe that eating more fruits and vegetables can prevent disease. These findings underscore the need for efforts to reach the rural black community with culturally sensitive and stage appropriate cancer prevention messages. Knowledge of family history of cancer may play an important role in targeting subgroups and delivering effective cancer prevention messages. 相似文献
12.
13.
S E Campbell C D Phillips E Dubovsky W S Cail R A Omary 《AJNR. American journal of neuroradiology》1995,16(7):1385
PURPOSETo determine whether plain films alone are sufficient in the evaluation of stability of simple wedge-compression fractures of the lumbar spine.METHODSPlain films and CT scans of 53 consecutive patients seen during a 2-year period with lumbar spine fractures were retrospectively reviewed. Six readers blinded to the CT diagnosis independently read each patient''s plain films. Plain-film findings were scored on a five-point graded response scale using criteria proposed by Gehweiler and Daffner. In addition, a fracture was considered to be possibly unstable if there was involvement of more than one vertebral level or greater than 50% loss of anterior vertebral body height. CT findings represented the standard for comparison. CT scans were independently evaluated by three additional readers. Two-column involvement, middle-column involvement alone but with retropulsion, multiple-level involvement, or greater than 50% loss of vertebral height indicated potential instability.RESULTSFor 14 stable and 39 potentially unstable lumbar spine fractures, the pooled (mean) plain-film negative predictive value for detection of potentially unstable fractures was 0.62 (95% confidence interval, 0.53 to 0.70), with a sensitivity of 0.83 (95%, confidence interval; 0.78 to 0.87), and specificity of 0.80 (95% confidence interval, 0.70 to 0.87).CONCLUSIONPlain films are not adequate for determining stability of lumbar spine fractures. 相似文献
14.
15.
16.
17.
18.
E. B. Austin F. Thistlethwaite S. Neeson P. Stern L. McDonald M. Hulston D. Gilham E. Elkord R. Griffiths R. Guest J. D. M. Campbell R. E. Hawkins 《Transfusion medicine (Oxford, England)》2006,16(Z1):8-8
The CXCL12/CXCR4 chemokine axis is a well characterized and important chemotactic stimulus/receptor unit that orchestrates the homing and migration of cells to the bone marrow and to ischemic tissues following tissue damage. Here, we demonstrate that the sialomucin, CD164, a regulator of haemopoietic precursor cell adhesion to stroma and entry of primitive CD34+CD38lo/‐ precursor cells into cycle, modulates the migration of CD133+ cord blood cells to CXCL12 by associating with the CXCR4 receptor. This was demonstrated by a reduction in CD133+ cell migration on fibronectin to CXCL12 (i) by engaging the functional class II glycosylation‐dependent epitope on CD164 with the 103B2/9E10 class II but not the N6B6 class III antibody; and (ii) by RNAi knockdown of CD164 protein levels in CD133+ cells. The inhibition of migration was more pronounced in the more primitive CD34+CD38lo/‐ cell subset. Similar studies using the Jurkat cell line confirmed these findings and led to further analyses using alternative chemokines. A direct association between CXCR4 and CD164 was demonstrated by the co‐localisation of CD164 with CXCR4 and VLA‐4 and VLA‐5 at the leading edge of CD133+ cells when CXCL12 was presented on fibronectin. This was further supported by immunoprecipitation studies that demonstrate in the absence of CXCL12, CXCR4 is associated only with VLA‐4 and VLA‐5 but on exposure to CXCL12, CD164 is rapidly recruited to the CXCR4 complex. Knock‐down of CD164 using siRNA revealed that signalling through CXCR4 via PKC‐ζ was significantly dampened. Our findings therefore support a novel association between three distinct families of cell surface receptors that regulate both cell migratory and proliferative responses and identify a CD164 as a key regulator of the CXCL12/CXCR4 axis. 相似文献
19.
For the management of a condition such as asthma, patients should feel confident with their medication, feel that the treatment is adequate in controlling symptoms and that side-effects of the treatment are minimal. As no comprehensive instrument to measure patient satisfaction with inhaled asthma medication existed, the Satisfaction with Asthma Treatment Questionnaire was developed. The procedures that were used are described, and the initial validation and reliability tests are reported. The study involved focus group meetings, development, testing and modification of a preliminary instrument, and testing of the revised instrument using different samples of patients with asthma. Factor analysis of the 26-item questionnaire identified four domains reflecting four aspects of satisfaction: effectiveness of treatment, ease of use, medication burden, and side-effects and worries. Cronbach's alpha showed evidence of internal consistency reliability. Test/retest reliability ranged from 0.66-0.74. Interscale correlations were moderate-to-high. Significant correlations were found between domain and overall scale scores and patients' overall level of satisfaction. The Satisfaction with Asthma Treatment Questionnaire is potentially a useful instrument for gaining insight into patient satisfaction with inhaled treatment for asthma. 相似文献
20.