全文获取类型
收费全文 | 1280篇 |
免费 | 101篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 68篇 |
妇产科学 | 36篇 |
基础医学 | 146篇 |
口腔科学 | 10篇 |
临床医学 | 191篇 |
内科学 | 243篇 |
皮肤病学 | 64篇 |
神经病学 | 118篇 |
特种医学 | 32篇 |
外科学 | 100篇 |
综合类 | 7篇 |
一般理论 | 2篇 |
预防医学 | 139篇 |
眼科学 | 13篇 |
药学 | 64篇 |
肿瘤学 | 144篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 17篇 |
2021年 | 32篇 |
2020年 | 26篇 |
2019年 | 44篇 |
2018年 | 49篇 |
2017年 | 31篇 |
2016年 | 40篇 |
2015年 | 49篇 |
2014年 | 49篇 |
2013年 | 68篇 |
2012年 | 95篇 |
2011年 | 93篇 |
2010年 | 55篇 |
2009年 | 55篇 |
2008年 | 77篇 |
2007年 | 96篇 |
2006年 | 77篇 |
2005年 | 60篇 |
2004年 | 70篇 |
2003年 | 75篇 |
2002年 | 65篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 2篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1972年 | 2篇 |
1940年 | 2篇 |
1938年 | 2篇 |
1935年 | 1篇 |
1932年 | 1篇 |
1931年 | 2篇 |
排序方式: 共有1386条查询结果,搜索用时 15 毫秒
1.
Sherry X Yang Richard M Simon Antoinette R Tan Diana Nguyen Sandra M Swain 《Clinical cancer research》2005,11(17):6226-6232
PURPOSE: To delineate gene expression patterns and profile changes in metastatic tumor biopsies at baseline and 1 month after treatment with the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib in patients with metastatic breast cancer. EXPERIMENTAL DESIGN: Patients were treated with 150 mg of oral erlotinib daily. Gene expression profiles were measured with Affymetrix U133A GeneChip and immunohistochemistry was used to validate microarray findings. RESULTS: Estrogen receptor (ER) status by immunohistochemistry is nearly coincided with the two major expression clusters determined by expression of genes using unsupervised hierarchical clustering analysis. One of 10 patients had an EGFR-positive tumor detected by both microarray and immunohistochemistry. In this tumor, tissue inhibitor of metalloproteinases-3 and collagen type 1 alpha 2, which are the EGF-down-regulated growth repressors, were significantly increased by erlotinib. Gene changes in EGFR-negative tumors are those of G-protein-linked and cell surface receptor-linked signaling. Gene ontology comparison analysis pretreatment and posttreatment in EGFR-negative tumors revealed biological process categories that have more genes differentially expressed than expected by chance. Among 495 gene ontology categories, the significant differed gene ontology groups include G-protein-coupled receptor protein signaling (34 genes, P = 0.002) and cell surface receptor-linked signal transduction (74 genes, P = 0.007). CONCLUSIONS: ER status reflects the major difference in gene expression pattern in metastatic breast cancer. Erlotinib had effects on genes of EGFR signaling pathway in the EGFR-positive tumor and on gene ontology biological process categories or genes that have function in signal transduction in EGFR-negative tumors. 相似文献
2.
3.
Scarlett Lin Gomez Cynthia D O'Malley Antoinette Stroup Sarah J Shema William A Satariano 《BMC cancer》2007,7(1):193
Background
Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods. 相似文献4.
5.
Alex L. van Bemmel Rutger H. van den Hoofdakker Domien G. M. Beersma Antoinette L. Bouhuys 《Psychopharmacology》1993,113(2):225-230
Drug-induced improvement of depression may be mediated by changes in sleep physiology. The aim of this study was to relate changes in sleep polygraphic variables to clinical state during treatment with citalopram, a highly specific serotonin uptake inhibitor. Sixteen patients took part. The study was single-blind and uncontrolled. A 1-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a 1-week placebo period. For the entire group a significant decrease of rapid eye movement sleep (REMS) and a significant lengthening of REMS latency were observed initially as well as at the end of treatment. No changes in sleep continuity were found, but non-REMS stage 2 (percentage) was significantly increased. On the basis of clinical change, as expressed by the scores of the Hamilton Rating Scale for Depression, at the end of the citalopram treatment the patient group was split in two halves: eight less and eight more improved patients. The groups did not differ with respect to any sleep polygraphic varible. 相似文献
6.
Antoinette MaassenVanDenBrink MSc ; Monique N. Vergouwe MSc ; Roel A. Ophoff PhD ; Pramod R. Saxena MD PhD ; Michel D. Ferrari MD PhD ; Rune R. Frants PhD 《Headache》1998,38(4):288-291
The 5-HT1 receptor agonist, sumatriptan, is highly effective in the treatment of migraine. Some patients, however, do not respond or experience recurrence of the headache. In addition, some patients report chest symptoms after sumatriptan. We investigated whether these different responses could be attributed to genetic diversity of the 5-HT1B receptor, which most likely mediates the therapeutic action and the coronary side effects of sumatriptan. Allele frequencies of two polymorphisms in the 5-HT1B receptor gene ( G861C and T-261G ) were investigated in migraine patients with consistently good response to sumatriptan (n=14), with no response (n=12), with recurrence of the headache (n=12), with chest symptoms (n=13), and in patients without chest symptoms (n=27). Allele frequencies (G:0.74; C:0.26 at nt 861 and T:0.39; G:0.61 at nt -261) did not differ between patient groups, indicating that genetic diversity of the 5-HT1B receptor does not seem to be involved in the different clinical responses to sumatriptan. 相似文献
7.
Mersch PP Vastenburg NC Meesters Y Bouhuys AL Beersma DG van den Hoofdakker RH den Boer JA 《Journal of affective disorders》2004,80(2-3):209-219
Background: The Seasonal Pattern Assessment Questionnaire (SPAQ) is a frequently used screening instrument in the research on Seasonal Affective Disorder (SAD). Nevertheless, studies on its reliability and validity are relatively scarce. In the present study the reliability and the contrast validity of the SPAQ are investigated. Methods: SAD patients, selected by means of a clinical interview, non-seasonal depressed out-patients, non-depressed out-patients, and a control group, are contrasted to estimate the discriminating power of the SPAQ. Also, the reliability and factor structure of the seasonality and the climate subscales are investigated. To study food intake the Seasonal Food Preference Questionnaire (SFPQ) was developed. Results: The SAD criterion of the SPAQ shows good specificity (94%), but a low sensitivity (44%). Discriminant analysis shows sufficient ability to classify subjects (81% correctly classified). The Global Seasonality Scale has a good internal consistency. It consists of two factors, a psychological factor and a food factor. The SFPQ is sensitive for carbohydrate intake by SAD patients. Limitations: Most SAD patients had received treatment and completed the SPAQ while they were not depressed, which may have influenced the sensitivity. Conclusions: The SPAQ is not sensitive enough to be considered a diagnostic instrument for SAD. Nevertheless, it is accurate enough to be used as a screenings instrument. The only false positives were found in the depressive group. The accuracy of prevalence Figs. can be improved by completion of the SPAQ in the summer months, combined with the completion of a depression scale. 相似文献
8.
Brink AA Wiegant JC Szuhai K Tanke HJ Kenter GG Fleuren GJ Schuuring E Raap AK 《Cancer Genetics and Cytogenetics》2002,134(2):145-150
Infection with high-risk type human papillomavirus (HPV) is a necessary causal factor in the pathogenesis of cervical carcinoma. In most invasive cervical cancers, HPV is integrated in the host cell genome, and additional genetic aberrations are observed among which are chromosomal aberrations. To analyze in detail such often complex chromosomal changes and simultaneously map HPV integration sites, we extended the multiplicity of the combined binary ratio labeling fluorescence in situ hybridization (COBRA-FISH) technique to 49 by inclusion of a large Stokes' shift fluorochrome as the third binary label. The technique allows mapping of the integrated HPV genome in the context of p- and q-arm COBRA-FISH, with a sensitivity of one copy of the HPV genome as tested for HPV 16 in SiHa cells. We investigated the molecular karyotypes and integration patterns of HPV types 16 and 18 in metaphase spreads from short-term cultures of primary cervical carcinomas (n=5). Of the tested cervical carcinomas, two contained integrated HPV at 8q24, one of which in addition harbored the integrated virus near a translocation breakpoint. Two carcinomas had integrated HPV at 17q21 through 23 in a morphologically normal chromosome 17. One carcinoma contained HPV at 1q42 in a morphologically normal chromosome 1. Our data illustrate the efficacy of 49-color COBRA-FISH to resolve complex karyotypes and simultaneously map specific sequences in metaphases obtained from short-term solid tumor cultures. 相似文献
9.
Caron Kim Antoinette T. Nguyen Erin Berry-Bibee Yokabed Ermias Mary E. Gaffield Nathalie Kapp 《Contraception》2021,103(5):291-304
BackgroundImmediate contraceptive initiation, including start of a method before abortion completion, is a convenient option for women seeking abortion care.ObjectivesTo evaluate the effect of systemic hormonal contraception initiation on medical abortion effectiveness and the safety of hormonal contraceptive methods following abortion.Data sourcesPubMed, Popline, Cochrane Library, and Clinicaltrials.gov.Study eligibility criteriaStudies that assessed medical abortion effectiveness after systemic hormonal contraception initiation and the safety of hormonal contraception initiation after abortion.ParticipantsPregnant persons undergoing or who had recently undergone an abortion.InterventionsInitiation of systemic hormonal contraception post abortion or on the day of the first pill of the medical abortion.Study appraisal and synthesis methodsWe assessed study quality using the US Preventive Services Task Force evidence grading system. We created narrative summaries and calculated pooled relative risks when appropriate.ResultsWe identified 16 studies for inclusion, 7 randomized controlled trials, and 9 cohorts. Nine studies assessed medical abortion effectiveness with hormonal contraception initiation and generally found no decreased risk of abortion success or increased risk of additional treatment. One fair-quality study reported a small increase in ongoing pregnancy rate with immediate depot medroxyprogesterone (DMPA) compared with delayed DMPA initiation (3.6% vs 0.9%, risk difference 2.7%, 90% confidence interval 0.4–5.6). We identified no bleeding-related safety concerns following hormonal contraception initiation after medical or surgical abortion. Pooled results were too imprecise to draw firm conclusions.LimitationsIncluded studies were poor or fair quality and primarily in high-income or upper-middle-income settings.ConclusionsAbortion effectiveness did not differ between immediate vs delayed initiation of most systemic hormonal contraceptive methods after a first trimester medical abortion. However, immediate DMPA initiation did show increased ongoing pregnancy. Bleeding effects with hormonal contraception initiation postabortion appeared minimal.ImplicationsInitiating a hormonal contraceptive method after an abortion and as early as the same day as the first pill of the medical abortion is an option if contraception is desired. The slight increase in ongoing pregnancy with immediate DMPA initiation highlights the importance of information provision during contraceptive counseling. 相似文献
10.
Martijn Felder Hester van de Bovenkamp Willem Jan Meerding Antoinette de Bont 《Health policy (Amsterdam, Netherlands)》2021,125(1):34-40
We critically examine the discussion on the role of evidence-based medicine (EBM) in healthcare governance. We take the institutionally layered Dutch healthcare system as our case study. Here, different actors are involved in the regulation, provision and financing of healthcare services. Over the last decades, these actors have related to EBM to inform their actor specific roles. At the same time, EBM has increasingly been problematised. To better understand this problematisation, we organised focus groups and interviews. We noticed that particularly EBM’s reductionist epistemology and its uncritical use by ‘professional others’ are considered problematic. However, our analysis also reveals that something else seems to be at stake. In fact, all the actors involved underwrite EBM’s reductionist epistemology and emphasise that evidence should be contextualised. They however do so in different ways and with different contexts in mind. Moreover, the ways in which some actors contextualise evidence has consequences for the ways in which others can do the same. We therefore emphasise that behind EBM’s scientific problematisation lurks a political issue. A dispute over who should contextualise evidence how, in a layered healthcare system with interdependent actors that cater to both individual patients and the public. We urge public administration scholars and policymakers to open-up the political confrontation between healthcare actors and their sometimes irreconcilable, yet evidence-informed perspectives. 相似文献