全文获取类型
收费全文 | 913篇 |
免费 | 62篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 11篇 |
妇产科学 | 19篇 |
基础医学 | 71篇 |
口腔科学 | 22篇 |
临床医学 | 85篇 |
内科学 | 118篇 |
皮肤病学 | 10篇 |
神经病学 | 36篇 |
特种医学 | 15篇 |
外科学 | 97篇 |
综合类 | 102篇 |
预防医学 | 119篇 |
眼科学 | 21篇 |
药学 | 193篇 |
1篇 | |
中国医学 | 38篇 |
肿瘤学 | 26篇 |
出版年
2023年 | 9篇 |
2022年 | 21篇 |
2021年 | 21篇 |
2020年 | 31篇 |
2019年 | 37篇 |
2018年 | 27篇 |
2017年 | 39篇 |
2016年 | 33篇 |
2015年 | 30篇 |
2014年 | 48篇 |
2013年 | 77篇 |
2012年 | 60篇 |
2011年 | 63篇 |
2010年 | 46篇 |
2009年 | 55篇 |
2008年 | 42篇 |
2007年 | 54篇 |
2006年 | 41篇 |
2005年 | 31篇 |
2004年 | 29篇 |
2003年 | 31篇 |
2002年 | 23篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 18篇 |
1998年 | 6篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
排序方式: 共有990条查询结果,搜索用时 15 毫秒
1.
2.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):449-459.e4
ObjectiveThe objective of this study was to investigate the association between morphological variation and postsurgical pulmonary vein (PV) stenosis (PPVS) in patients with cardiac total anomalous pulmonary venous connection (TAPVC).MethodsThis single-center, retrospective study included 168 pediatric patients who underwent surgical repair of cardiac TAPVC from 2013 to 2019 (connection to the coronary sinus [CS], n = 136; connection directly to the right atrium [RA], n = 32). Three-dimensional computed tomography modeling and geometric analysis were performed to investigate the morphological features; their relevance to the PPVS was examined.ResultsThe connection type had no association with PPVS (CS type: 18% vs right atrial type: 19%; P = .89) but there was a higher incidence of PPVS in patients with a single PV orifice than > 1 orifice (P < .001). Confluence-to-total PV area ratio (hazard ratio, 4.78, 95% CI, 1.86-12.32; P = .001) and length of drainage route (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < .001) had a 4- and 1-fold increase in the risk for PPVS in the CS type after adjustment for age and preoperative pulmonary venous obstruction. In the right atrial type, those with anomalous PV return to the RA roof were more likely to develop PPVS than to the posterior wall of the RA (P < .001).ConclusionsThe number of inter-junction PV orifice correlated with PPVS development in cardiac TAPVC. The confluence-to-total PV ratio, length of drainage route, and anomalous PV return to the RA roof are important predictors for PPVS. Morphological subcategorization in this clinical setting can potentially assist in surgical decision-making. 相似文献
3.
Objective
To determine the association between provider training level and postplacental intrauterine device (IUD) outcomes following insertion instruction by email only.Study design
We conducted a single-center chart review of demographics, insertion and clinical outcomes within 6 months of delivery for 116 patients who underwent postplacental levonorgestrel 52?mg IUD placement from October 1, 2016, to March 31, 2017.Results
We confirmed IUD retention, removal or expulsion in 87 of 116 (75.0%) patients by 6 months after delivery. Complete expulsion or removal for malposition occurred in 20 (23.0%) patients and more frequently after vaginal than cesarean delivery (30.2% vs. 4.2%, OR 9.93 [95% CI 1.25–78.96]) and when a postgraduate year (PGY) 1 physician placed the IUD compared to a PGY 2–4 or attending physician (37.5% vs. 14.5%, OR 3.52 [95% CI 1.25–9.94]).Conclusion
Postplacental levonorgestrel 52?mg IUD expulsion rates are associated with provider training level as well as delivery route, though the individual association of each of these factors is difficult to ascertain given the high degree of collinearity between these two variables in our study. 相似文献4.
《Alzheimer's & dementia》2019,15(10):1286-1295
IntroductionIt is unclear the degree to which tau pathology in the medial temporal lobe (MTL) measured by 18F-flortaucipir positron emission tomography relates to MTL subregional atrophy and whether this relationship differs between amyloid-β–positive and amyloid-β–negative individuals.MethodsWe analyzed correlation of MTL 18F-flortaucipir uptake with MTL subregional atrophy measured with high-resolution magnetic resonance imaging in a region of interest and regional thickness analysis and determined the relationship between memory performance and positron emission tomography and magnetic resonance imaging measures.ResultsBoth groups showed strong correlations between 18F-flortaucipir uptake and atrophy, with similar spatial patterns. Effects in the rhinal cortex recapitulated Braak staging. Correlations of memory recall with atrophy and tracer uptake were observed.DiscussionCorrelation patterns between tau burden and atrophy in the amyloid-β–negative group mimicking early Braak stages suggests that 18F-flortaucipir is sensitive to tau pathology in primary age-related tauopathy. Correlations of imaging measures with memory performance indicate that this pathology is associated with poorer cognition. 相似文献
5.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2020,30(1):84-91
Background and aimsDiabetes can often remain undiagnosed or unregistered in administrative databases long after its onset, even when laboratory test results meet diagnostic criteria. In the present work, we analyse healthcare data of the Veneto Region, North East Italy, with the aims of: (i) developing an algorithm for the identification of diabetes from administrative claims (4,236,007 citizens), (ii) assessing its reliability by comparing its performance with the gold standard clinical diagnosis from a clinical database (7525 patients), (iii) combining the algorithm and the laboratory data of the regional Health Information Exchange (rHIE) system (543,520 subjects) to identify undiagnosed diabetes, and (iv) providing a credible estimate of the true prevalence of diabetes in Veneto.Methods and resultsThe proposed algorithm for the identification of diabetes was fed by administrative data related to drug dispensations, outpatient visits, and hospitalisations. Evaluated against a clinical database, the algorithm achieved 95.7% sensitivity, 87.9% specificity, and 97.6% precision. To identify possible cases of undiagnosed diabetes, we applied standard diagnostic criteria to the laboratory test results of the subjects who, according to the algorithm, had no diabetes-related claims. Using a simplified probabilistic model, we corrected our claims-based estimate of known diabetes (6.17% prevalence; 261,303 cases) to account for undiagnosed cases, yielding an estimated total prevalence of 7.50%.ConclusionWe herein validated an algorithm for the diagnosis of diabetes using administrative claims against the clinical diagnosis. Together with rHIE laboratory data, this allowed to identify possibly undiagnosed diabetes and estimate the true prevalence of diabetes in Veneto. 相似文献
6.
7.
Adeline Tarantini Sylvie Huet Gérard Jarry Rachelle Lanceleur Martine Poul Ana Tavares Nádia Vital Henriqueta Louro Maria João Silva Valérie Fessard 《Environmental and molecular mutagenesis》2015,56(2):218-227
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
8.
9.
Yu Wang Shuo Wang Xiao N. Feng Li C. Yan Shan S. Zheng Yue Wang 《Drug and chemical toxicology》2018,41(1):95-104
Relationships of toxicities from intravenous (i.v.), intraperitoneal (i.p.), subcutaneous (s.c.) and intragastric (i.g.) exposure routes to mice were investigated. Regression analysis showed that the toxicities from i.v. route is strongly correlated with i.p. and s.c. routes, but poorly with i.g. route. Close toxicities from different routes for some compounds indicate that distribution rate is the determining step and dictates chemical concentration at the target site(s). On the other hand, the absorption rate is the determining step for many compounds, which lead to different toxicities between exposure routes. The classified compounds characterized as having either absorption or distribution rate determining step were based upon the comparison of toxicities from the different routes. We found that some aliphatic acids and benzoic acids have lower toxicity values from i.g. route compared to an i.v. route because of poor absorption. Many compounds show low toxic effects from i.g. route than those from other routes because of the first-pass metabolism in the gastrointestinal tract, resulting in the poor relationship for toxicities between i.g. and i.v. or other routes. Stepwise regression analysis showed that physicochemical properties of a compound, such as molecular volume, polarizability and hydrophobicity, significantly affect adsorption rate, which leads to different toxicities based upon exposure routes. Comparison of the toxicities between mice and rats indicate that toxic effect and the toxicokinetic processes in mice are very similar to that in rats. A universal correlation equation has been developed for the toxicities between rats and mice from different exposure routes, which can be applied to predict toxicities across species. 相似文献
10.
Hiroyuki Shimada Hyuma Makizako Takehiko Doi Hyuntae Park Kota Tsutsumimoto Joe Verghese Takao Suzuki 《Journal of the American Medical Directors Association》2018,19(7):584-591