全文获取类型
收费全文 | 2587898篇 |
免费 | 184524篇 |
国内免费 | 7558篇 |
专业分类
耳鼻咽喉 | 34273篇 |
儿科学 | 85200篇 |
妇产科学 | 71568篇 |
基础医学 | 363610篇 |
口腔科学 | 69646篇 |
临床医学 | 234493篇 |
内科学 | 515491篇 |
皮肤病学 | 62450篇 |
神经病学 | 213439篇 |
特种医学 | 99877篇 |
外国民族医学 | 736篇 |
外科学 | 386404篇 |
综合类 | 50390篇 |
现状与发展 | 5篇 |
一般理论 | 968篇 |
预防医学 | 196197篇 |
眼科学 | 56665篇 |
药学 | 187974篇 |
8篇 | |
中国医学 | 5331篇 |
肿瘤学 | 145255篇 |
出版年
2021年 | 19980篇 |
2019年 | 20623篇 |
2018年 | 29287篇 |
2017年 | 22592篇 |
2016年 | 26225篇 |
2015年 | 29503篇 |
2014年 | 40447篇 |
2013年 | 60427篇 |
2012年 | 80223篇 |
2011年 | 84487篇 |
2010年 | 51003篇 |
2009年 | 49144篇 |
2008年 | 79024篇 |
2007年 | 83835篇 |
2006年 | 85564篇 |
2005年 | 81730篇 |
2004年 | 78732篇 |
2003年 | 76045篇 |
2002年 | 73334篇 |
2001年 | 128410篇 |
2000年 | 131332篇 |
1999年 | 110498篇 |
1998年 | 31252篇 |
1997年 | 27919篇 |
1996年 | 28217篇 |
1995年 | 27383篇 |
1994年 | 25069篇 |
1993年 | 23419篇 |
1992年 | 85160篇 |
1991年 | 81563篇 |
1990年 | 78784篇 |
1989年 | 76061篇 |
1988年 | 69469篇 |
1987年 | 67996篇 |
1986年 | 63542篇 |
1985年 | 60510篇 |
1984年 | 44943篇 |
1983年 | 37944篇 |
1982年 | 22457篇 |
1981年 | 19984篇 |
1979年 | 38959篇 |
1978年 | 27439篇 |
1977年 | 23252篇 |
1976年 | 21495篇 |
1975年 | 22813篇 |
1974年 | 26786篇 |
1973年 | 25370篇 |
1972年 | 23749篇 |
1971年 | 21955篇 |
1970年 | 20183篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
173.
O. Morris M. Fairclough J. Grigg C. Prenant A. McMahon 《Journal of labelled compounds & radiopharmaceuticals》2019,62(1):4-23
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs. 相似文献
174.
W. Do T. Elzerman R. de Bree A. Rosenberg T. Forouzanfar E.M. Van Cann 《International journal of oral and maxillofacial surgery》2021,50(5):591-597
The aim of this study was to analyse the effect of body mass index (BMI), both low and high values, on the perioperative complication rate in patients with oral squamous cell carcinoma (OSCC). The medical records of 259 patients operated between 2014 and 2017 for OSCC were reviewed. Univariate and multivariate analyses were performed. Sixty of the 259 patients developed 87 complications. Low or high BMI was not associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. Low BMI, American Society of Anesthesiologists score 2 and 3, a longer operating time, and increased blood loss were associated with a longer hospital stay. Low BMI was associated with a longer hospital stay. Neither low nor high BMI was associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. 相似文献
175.
176.
Y. Ermias I.A. Morgan K.M. Curtis M.K. Whiteman L.G. Horton L.B. Zapata 《Contraception》2019,99(5):300-305
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception. 相似文献
177.
Rian M. Hasson Kayla A. Fay Joseph D. Phillips Timothy M. Millington David J. Finley 《American journal of surgery》2021,221(4):725-730
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations. 相似文献
178.
Erik de Bakker Mirthe A. M. van der Putten Martijn W. Heymans Sander W. Spiekstra Taco Waaijman Liselotte Butzelaar Vera L. Negenborn Vivian K. Beekman Erman O. Akpinar Thomas Rustemeyer Frank B. Niessen Susan Gibbs 《Experimental dermatology》2021,30(1):169-178
Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R2: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice. 相似文献
179.
Prevention Science - This study aimed to evaluate the effectiveness of the drug and violence resistance educational program (PROERD) on short-term secondary outcomes, such as intentions to use... 相似文献
180.