全文获取类型
收费全文 | 2350138篇 |
免费 | 171233篇 |
国内免费 | 3319篇 |
专业分类
耳鼻咽喉 | 32053篇 |
儿科学 | 75894篇 |
妇产科学 | 62685篇 |
基础医学 | 348166篇 |
口腔科学 | 63620篇 |
临床医学 | 211342篇 |
内科学 | 457269篇 |
皮肤病学 | 51727篇 |
神经病学 | 185263篇 |
特种医学 | 88006篇 |
外国民族医学 | 489篇 |
外科学 | 353855篇 |
综合类 | 47508篇 |
现状与发展 | 12篇 |
一般理论 | 848篇 |
预防医学 | 182729篇 |
眼科学 | 54325篇 |
药学 | 175106篇 |
11篇 | |
中国医学 | 4575篇 |
肿瘤学 | 129207篇 |
出版年
2021年 | 18979篇 |
2019年 | 19537篇 |
2018年 | 27057篇 |
2017年 | 20357篇 |
2016年 | 22746篇 |
2015年 | 25638篇 |
2014年 | 36094篇 |
2013年 | 53955篇 |
2012年 | 74675篇 |
2011年 | 79407篇 |
2010年 | 47056篇 |
2009年 | 44565篇 |
2008年 | 74609篇 |
2007年 | 79477篇 |
2006年 | 80295篇 |
2005年 | 77779篇 |
2004年 | 74366篇 |
2003年 | 71690篇 |
2002年 | 69365篇 |
2001年 | 108738篇 |
2000年 | 111451篇 |
1999年 | 93495篇 |
1998年 | 26990篇 |
1997年 | 23658篇 |
1996年 | 24054篇 |
1995年 | 22715篇 |
1994年 | 20893篇 |
1993年 | 19712篇 |
1992年 | 72000篇 |
1991年 | 70069篇 |
1990年 | 68391篇 |
1989年 | 65663篇 |
1988年 | 60302篇 |
1987年 | 59125篇 |
1986年 | 55217篇 |
1985年 | 53004篇 |
1984年 | 39311篇 |
1983年 | 33396篇 |
1982年 | 19858篇 |
1979年 | 35866篇 |
1978年 | 25651篇 |
1977年 | 21230篇 |
1976年 | 20332篇 |
1975年 | 21816篇 |
1974年 | 26148篇 |
1973年 | 24802篇 |
1972年 | 23200篇 |
1971年 | 22037篇 |
1970年 | 20247篇 |
1969年 | 19315篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
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
142.
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
143.
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
144.
Mt D. Dbrssy Chockalingam Ramanathan Danesh Ashouri Vajari Yixin Tong Thomas Schlaepfer Volker A. Coenen 《The European journal of neuroscience》2021,53(1):89-113
Deep brain stimulation (DBS) in psychiatric illnesses has been clinically tested over the past 20 years. The clinical application of DBS to the superolateral branch of the medial forebrain bundle in treatment‐resistant depressed patients—one of several targets under investigation—has shown to be promising in a number of uncontrolled open label trials. However, there are remain numerous questions that need to be investigated to understand and optimize the clinical use of DBS in depression, including, for example, the relationship between the symptoms, the biological substrates/projections and the stimulation itself. In the context of precision and customized medicine, the current paper focuses on clinical and experimental research of medial forebrain bundle DBS in depression or in animal models of depression, demonstrating how clinical and scientific progress can work in tandem to test the therapeutic value and investigate the mechanisms of this experimental treatment. As one of the hypotheses is that depression engenders changes in the reward and motivational networks, the review looks at how stimulation of the medial forebrain bundle impacts the dopaminergic system. 相似文献
145.
Gordon K. B. Saburov V. O. Koryakin S. N. Gulidov I. A. Fatkhudinov T. Kh. Arutyunyan I. V. Kaprin A. D. Solov’ev A. N. 《Bulletin of experimental biology and medicine》2022,173(2):281-285
Bulletin of Experimental Biology and Medicine - Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a... 相似文献
146.
Biomedical Engineering - Different approaches to correction of the ECG signal baseline drift are compared. A new adaptive method for correction of the baseline drift is proposed. The method is... 相似文献
147.
Sarah E. Henderson Shana A. Hall Jessica M. Callegari James A. Desjardins Sidney J. Segalowitz Karen L. Campbell 《Psychophysiology》2022,59(1):e13947
Recent work suggests that while voluntary episodic memory declines with age, involuntary episodic memory, which comes to mind spontaneously without intention, remains relatively intact. However, the neurophysiology underlying these differences has yet to be established. The current study used electroencephalography (EEG) to investigate voluntary and involuntary retrieval in older and younger adults. Participants first encoded sounds, half of which were paired with pictures, the other half unpaired. EEG was then recorded as they listened to the sounds, with participants in the involuntary group performing a sound localization cover task, and those in the voluntary group additionally attempting to recall the associated pictures. Participants later reported which sounds brought the paired picture to mind during the localization task. Reaction times on the localization task were slower for voluntary than involuntary retrieval and for paired than unpaired sounds, possibly reflecting increased attentional demands of voluntary retrieval and interference from reactivation of the associated pictures respectively. For the EEG analyses, young adults showed greater alpha event-related desynchronization (ERD) during voluntary than involuntary retrieval at frontal and occipital sites, while older adults showed pronounced alpha ERD regardless of intention. Additionally, older adults showed greater ERD for paired than unpaired sounds at occipital sites, likely reflecting visual reactivation of the associated pictures. Young adults did not show this alpha ERD memory effect. Taken together, these data suggest that involuntary memory is largely preserved with age, but this may be due to older adults' greater recruitment of top-down control even when demand for such control is limited. 相似文献
148.
Joseph Wheatley Zhengyang Liu Joel Loth Mark P. Plummer Jahan C. Penny-Dimri Reny Segal Julian Smith Luke A. Perry 《Acta anaesthesiologica Scandinavica》2023,67(2):131-141
Background
Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil–lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.Methods
We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.Results
Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18–1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50–3.72). Postoperative NLR measurements were not of prognostic significance.Conclusions
Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery. 相似文献149.
Gregory S. Orgel Robert A. Weston Christopher Ziebell Lawrence H. Brown 《The American journal of emergency medicine》2019,37(9):1729-1733
ObjectiveTo evaluate changes in insurance status among emergency department (ED) patients presenting in the two years immediately before and after full implementation of the Affordable Care Act (ACA).MethodsWe evaluated National Hospital Ambulatory Medical Care Survey (NHAMCS) Emergency Department public use data for 2012–2015, categorizing patients as having any insurance (private; Medicare; Medicaid; workers' compensation) or no insurance. We compared the pre- and post-ACA frequency of insurance coverage—overall and within the older (≥65), working-age (18–64) and pediatric (<18) subpopulations—using unadjusted odds ratios with 95% confidence intervals. We also conducted a difference-in-differences analysis comparing the change in insurance coverage among working-age patients with that observed for older Medicare-eligible patients, while controlling for sex, race and underlying temporal trends.ResultsOverall, the proportion of ED patients with any insurance did not significantly change from 2012 to 2013 to 2014–2015 (74.2% vs 77.7%) but the proportion of working-age adult patients with at least one form of insurance increased significantly, from 66.0% to 71.8% (OR 1.31, CI: 1.13–1.52). The difference-in-differences analysis confirmed the change in insurance coverage among working-age adults was greater than that seen in the reference population of Medicare-eligible adults (AOR 1.70, CI: 1.29–2.23). The increase was almost entirely attributable to increased Medicaid coverage.ConclusionIn the first two years following full implementation of the ACA, there was a significant increase in the proportion of working-age adult ED patients who had at least one form of health insurance. The increase appeared primarily associated with expansion of Medicaid. 相似文献
150.
van der Heijden Amber A. W. A. de Bruijne Martine C. Nijpels Giel Hugtenburg Jacqueline G. 《International journal of clinical pharmacy》2019,41(4):963-971
International Journal of Clinical Pharmacy - Background Drug-related problems (DRP) following hospital discharge may cause morbidity, mortality and hospital re-admissions. It is unclear whether a... 相似文献