全文获取类型
收费全文 | 19871篇 |
免费 | 1967篇 |
国内免费 | 447篇 |
专业分类
耳鼻咽喉 | 91篇 |
儿科学 | 652篇 |
妇产科学 | 342篇 |
基础医学 | 1284篇 |
口腔科学 | 173篇 |
临床医学 | 2008篇 |
内科学 | 2300篇 |
皮肤病学 | 259篇 |
神经病学 | 849篇 |
特种医学 | 2048篇 |
外国民族医学 | 9篇 |
外科学 | 1824篇 |
综合类 | 2544篇 |
预防医学 | 2062篇 |
眼科学 | 218篇 |
药学 | 3203篇 |
27篇 | |
中国医学 | 561篇 |
肿瘤学 | 1831篇 |
出版年
2024年 | 11篇 |
2023年 | 299篇 |
2022年 | 488篇 |
2021年 | 753篇 |
2020年 | 780篇 |
2019年 | 730篇 |
2018年 | 773篇 |
2017年 | 769篇 |
2016年 | 750篇 |
2015年 | 699篇 |
2014年 | 1636篇 |
2013年 | 1696篇 |
2012年 | 1283篇 |
2011年 | 1440篇 |
2010年 | 1081篇 |
2009年 | 977篇 |
2008年 | 999篇 |
2007年 | 913篇 |
2006年 | 736篇 |
2005年 | 635篇 |
2004年 | 531篇 |
2003年 | 495篇 |
2002年 | 443篇 |
2001年 | 388篇 |
2000年 | 299篇 |
1999年 | 298篇 |
1998年 | 231篇 |
1997年 | 203篇 |
1996年 | 175篇 |
1995年 | 179篇 |
1994年 | 152篇 |
1993年 | 135篇 |
1992年 | 125篇 |
1991年 | 119篇 |
1990年 | 103篇 |
1989年 | 117篇 |
1988年 | 77篇 |
1987年 | 80篇 |
1986年 | 77篇 |
1985年 | 116篇 |
1984年 | 102篇 |
1983年 | 50篇 |
1982年 | 88篇 |
1981年 | 51篇 |
1980年 | 49篇 |
1979年 | 44篇 |
1978年 | 18篇 |
1977年 | 33篇 |
1976年 | 21篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Vaccine》2022,40(30):4038-4045
PurposeAs protection from COVID-19 following two doses of the BNT162b2 vaccine showed a time dependent waning, a third (booster) dose was administrated. This study aims to compare the antibody response following the third dose versus the second and to evaluate post-booster seroconversion.MethodsA prospective observational study conducted in Maccabi Healthcare Services. Serial SARS-CoV-2 Spike IgG tests, 1,2,3 and 6 months following the second vaccine dose and one month following the third were obtained. Neutralizing antibody levels were measured in a subset of participants. Per individual SARS-CoV-2 Spike IgG titer ratios were calculated one month after the booster administration compared to titers one month following the second dose and prior to booster.ResultsAmong 110 participants, 56 (51%) were women. Mean age was 61.7 ± 1.9 years and 66 (60%) were immunocompromised. One month after third dose, IgG titers were induced 7.83 (95 %CI 5.25–11.67) folds and 2.40 (95 %CI 1.90–3.03) folds compared to one month after the second, in the immunocompromised and immunocompetent groups, respectively. Of the 17 immunocompromised participants who were seronegative after the second dose, 4 (24%) became seropositive following the third. Comparing the titers prior to the third dose, an increase of 50.7 (95 %CI 32.5–79.1) fold in the immunocompromised group and 25.7 (95 %CI 19.1–34.7) fold in and immunocompetent group, was observed.ConclusionA third BNT162b2 vaccine elicited robust humoral response, superior to the response observed following the second, among immunocompetent and immunocompromised individuals. 相似文献
2.
3.
《Vaccine》2022,40(49):7151-7157
IntroductionRespiratory Syncytial Virus (RSV) is a major cause of acute lower respiratory tract infections (ALRI) in infants. There are no licensed vaccines and only one monoclonal antibody available to protect infants from disease. A new and potentially longer-lasting monoclonal antibody, Nirsevimab, showed promising results in phase IIb/III trials. We evaluate the cost-effectiveness of Nirsevimab intervention programmes in England and Wales.MethodsWe used a dynamic model for RSV transmission, calibrated to data from England and Wales. We considered a suite of potential Nirsevimab programmes, including administration to all neonates (year-round); only neonates born during the RSV season (seasonal); or neonates born during the RSV season plus infants less than six months old before the start of the RSV season (seasonal + catch-up).ResultsIf administered seasonally to all infants at birth, we found that Nirsevimab would have to be priced at £63 or less per dose for at least 50% certainty that it could cost-effectively replace the current Palivizumab programme, using an ICER threshold of £20,000/QALY. An extended seasonal programme which includes a pre-season catch-up becomes the optimal strategy at a purchasing price of £32/dose or less for at least 50% certainty. At a purchasing price per dose of £5-32, the annual implementation costs of a seasonal programme could be as high as £2 million before a switch to a year-round strategy would be optimal.DiscussionNirsevimab has the potential to be cost-effective in England and Wales not only for use in high-risk infants. 相似文献
4.
5.
《Zeitschrift für medizinische Physik》2022,32(2):209-217
This work describes a measurement method for assessing dose-related image-quality of CT scans based on the difference detail curve (DDC) method, and showcases its use in a low contrast setting. The method is based on a phantom consisting of elliptical slices of different sizes into which contrast object modules can be inserted. These modules contain contrast objects based on (synthetic) resin mixtures with sucrose (native) or sodium iodine (contrast medium). Mixing ratios are provided to achieve a range of clinically relevant CT-numbers with these materials. The phantom is characterized in terms of contrast accuracy, energy dependency and long-term drift with satisfying results. Contrast accuracy and energy dependency are similar to that of water or soft tissue. Image quality of 655 scans of the phantom acquired at 30 different clinical institutions and with 16 different CT scanner models from 4 manufacturers was assessed by calculating a difference detail curve (DDC) from evaluation of up to 5 human observers using a custom-made software (RadiVates) described in this work. Based on these measurements, inter-observer variability was quantified using a bootstrap method and was shown to be a large contributor to the overall variability. This work demonstrates that assessment of CT image quality is feasible with the aforementioned phantom and DDC method. 相似文献
6.
7.
目的探讨低分子量肝素在子痫前期患者中的应用效果。方法回顾性调查我院2019年1~4月290例子痫前期患者,根据产后1 d采用的治疗方法分为肝素组(190例)及对照组(100例),分析比较两组的一般资料和凝血指标差异。结果肝素组的新生儿体重和Apgar评分(1 min)低于对照组(P<0.05)。肝素组与对照组在产前仅凝血酶时间、D-二聚体、血小板体积分布宽度有差异,产后1 d肝素组纤维蛋白原含量、血小板计数、血小板压积低于对照组,凝血酶时间、D-二聚体、血小板体积分布宽度高于对照组(P<0.05)。产后3 d仅D-二聚体有差异。结论在产后1 d应用低分子量肝素有助于子痫前期患者产后凝血状态向正常恢复。 相似文献
8.
《Cancer radiothérapie》2022,26(4):611-615
In order to provide more convenient irradiation regimens for patient comfort, radiation facility organization and health expenses, new hypofractionated protocols have been evaluated. Moderately (dose/fraction: 2.3 to 3 Gy), then ultra (dose/fraction: 5.2 to 6.1 Gy) hypofractionated irradiations were first validated. The current question is: is it possible to go forward using extreme hypofractionated regimens (EHR) based on 1 to 3 fractions. Different irradiation techniques are under investigation. However, brachytherapy remains the smartest way to deliver a high dose in a small volume. We report prospective and retrospective study results which evaluated EHR for breast and prostate brachytherapy. While oncological outcome and toxicity profile appear extremely encouraging for low-risk breast cancer after a 1 to 4 fractions (6.25 to 20 Gy/fraction), the use of a single fraction of 19 to 23 Gy appears debatable for prostate cancer. Brachytherapy represents an emblematic example of EHR but longer follow-up and more mature results are awaited in order to specify the right indications and refine the EQD2 calculation method including new biological and technical factors. 相似文献
9.
《Nefrología : publicación oficial de la Sociedad Espa?ola Nefrologia》2022,42(2):163-170
IntroductionChronic inflammation and the underlying cardiovascular comorbidity are still current problems in chronic hemodialysis patients. There are few studies comparing the “dialysis dose” (Kt/V) with the degree of inflammation in the patient. Our main objective was to determine whether there is a relationship between serum C-reactive protein (CRP) levels and the Kt/V using ionic dialysance.MethodsMulticenter cross-sectional study. A total of 536 prevalent chronic hemodialysis patients were included. CRP levels, neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were collected. Kt was obtained by ionic dialysance and urea distribution volume was calculated from the Watson's formula. The sample was divided into 2 groups, taking the median CRP as the cut-off point. Dialysis adequacy obtained in each group was compared. Finally, a logistic regression model was carried out to determine the variables with the greatest influence.ResultsMedian CRP was 4.10 mg/L (q25-q75: 1.67-10) and mean Kt/V was 1.48 ± 0.308. Kt/V was lower in the patients included in the high inflammation group (P = .01). In the multivariate logistic regression, the “high” levels of CRP were directly correlated with the Log neutrophil-lymphocyte ratio (P < .001) and inversely proportional with serum albumin values (P = .014), Kt/V (P = .037) and serum iron (P < .001).ConclusionThe poorer adequacy in terms of dialysis doses (lower Kt/V values) may contribute to a higher degree of inflammation in chronic hemodialysis patients. 相似文献
10.
This meta-analysis was designed to assess the effectiveness and safety of extracorporeal shock wave therapy (ESWT) for patients with low back pain (LBP). Pubmed, Embase, Cochrane's library, PEDro (Physiotherapy Evidence Database), China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched until December 2019 to identify studies assessing the effectiveness and safety of EPSW for LBP. The prime outcome is pain intensity measured by Visual Analog Scale (VAS) or numeric rating scale (NRS). Other outcomes included functional status, quality of life, psychological outcomes measured by Oswestry Disability Index (ODI), as well as the adverse events. Mean differences (MD) were calculated for continuous outcomes, while odd ratios (OR) were calculated for binary outcomes. Revman 5.3 software was used for statistical analysis. Five randomized controlled trials (RCTs) were finally included in this meta-analysis. The pooled mean difference in post-treatment pain scores was −2.37 (P <0.0001), indicating that post-treatment pain scores was significantly higher by 2.37 in control group than in ESWT group. At a mean follow-up time of 4–6 weeks, the pooled mean difference in ODI scores was −14.10 (P <0.00001), indicating that the pooled mean difference of post-treatment ODI scores was 14.10 higher in control group than in ESWT group. The use of ESWT is effective in alleviating pain and improving the general functional state for patients with LBP. However, more evidence was needed to verify its safety. 相似文献