全文获取类型
收费全文 | 5679篇 |
免费 | 455篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 114篇 |
妇产科学 | 81篇 |
基础医学 | 1080篇 |
口腔科学 | 122篇 |
临床医学 | 498篇 |
内科学 | 1117篇 |
皮肤病学 | 171篇 |
神经病学 | 640篇 |
特种医学 | 223篇 |
外科学 | 473篇 |
综合类 | 12篇 |
一般理论 | 6篇 |
预防医学 | 571篇 |
眼科学 | 134篇 |
药学 | 335篇 |
中国医学 | 15篇 |
肿瘤学 | 524篇 |
出版年
2024年 | 4篇 |
2023年 | 58篇 |
2022年 | 86篇 |
2021年 | 184篇 |
2020年 | 120篇 |
2019年 | 161篇 |
2018年 | 159篇 |
2017年 | 179篇 |
2016年 | 192篇 |
2015年 | 232篇 |
2014年 | 254篇 |
2013年 | 335篇 |
2012年 | 504篇 |
2011年 | 505篇 |
2010年 | 286篇 |
2009年 | 270篇 |
2008年 | 389篇 |
2007年 | 418篇 |
2006年 | 364篇 |
2005年 | 354篇 |
2004年 | 294篇 |
2003年 | 283篇 |
2002年 | 227篇 |
2001年 | 34篇 |
2000年 | 25篇 |
1999年 | 35篇 |
1998年 | 37篇 |
1997年 | 35篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 23篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 6篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有6150条查询结果,搜索用时 31 毫秒
101.
102.
Oral cadmium exposure during rat pregnancy: assessment of transplacental micronutrient transport and steroidogenesis at term 下载免费PDF全文
Anja Mikolić Martina Piasek Antonija Sulimanec Grgec Veda M. Varnai Sandra Stasenko Saša Kralik Oguić 《Journal of applied toxicology : JAT》2015,35(5):508-519
Diet is the main source of cadmium (Cd) exposure. Gastrointestinal absorption increases during pregnancy. Cadmium accumulated in the placenta may interfere with nutrient transport to the foetus. Data on the potential of Cd to act as a steroid disruptor of pregnancy are limited. We evaluated the effects of oral Cd exposure during pregnancy on placental function in micronutrient transfer to the foetus and steroidogenesis in Wistar rats (regular 4‐day cyclers) that mated with unexposed males. Pregnant rats were randomly assigned to a Cd group exposed orally to 50 mg Cd l–1 (CdCl2xH2O dissolved in demineralized water), ≈7.5 mg Cd kg–1 a day, during 20 days of gestation and control (supplied with demineralized water). Non‐pregnant rats were treated under the same experimental conditions. On day 20, all of the rats were killed and samples were taken for element analyses (by electrothermal atomic absorption spectrometry). Progesterone and testosterone were measured in serum and placenta‐derived samples (by immunoenzymometric assay and/or enzyme‐linked immunosorbent assay). In the exposed rats, Cd increased in blood and organs, more in pregnant rats, and in placenta and foetus whereas zinc increased in liver. Iron decreased in maternal organs and in foetus, whereas zinc decreased in maternal kidney and placenta. Liver copper was lower and kidney copper higher in all pregnant vs. non‐pregnant rats. Steroids in serum and placenta did not change. In conclusion, oral Cd exposure during rat pregnancy does not affect progesterone and testosterone at term. Transplacental iron and zinc handover are disrupted, which may put at risk the maintenance of foetal nutrition and viability. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
103.
Dennis Hanke Maria Jenckel Anja Petrov Mathias Ritzmann Julia Stadler Valerij Akimkin Sandra Blome Anne Pohlmann Horst Schirrmeier Martin Beer Dirk H?per 《Emerging infectious diseases》2015,21(3):493-496
Since 2013, highly virulent porcine epidemic diarrhea virus has caused considerable economic losses in the United States. To determine the relation of US strains to those recently causing disease in Germany, we compared genomes and found that the strain from Germany is closely related to variants in the United States. 相似文献
104.
Jakob Ledwoch Ida Olbrich Felix Poch Ruth Thalmann Carmen Fellner Anja Stundl Christian Bradaric Karl-Ludwig Laugwitz Christian Kupatt 《The Canadian journal of cardiology》2021,37(3):443-449
BackgroundThere is growing body of evidence from retrospective studies that renin-angiotensin system (RAS) blockade is associated with improved outcome after transcatheter aortic valve replacement (TAVR). However, it remains unknown whether the effect of RAS blockade is dose dependent. The current study sought to assess the dose-dependent effect of RAS blockade on survival and left-ventricular (LV) remodelling after TAVR.MethodsPatients who were enrolled into our observational TAVR study at our institution were retrospectively assessed according to different doses of RAS blockade: group 1 (no RAS blockade), group 2 (25% of maximum daily dose), group 3 (50% of maximum daily dose), and group 4 (full daily dose).ResultsA total of 323 patients between January 2015 and September 2019 were included. Patients with higher doses of RAS blockade showed a trend toward higher overall survival at 3-year follow-up (56% with no RAS blockade vs 66% with the 25% dose vs 79% with the 50% dose vs 78% with the full dose; P = 0.063). After adjustment for baseline characteristics, the difference in survival was significant (P = 0.042). Besides New York Heart Association class and left-ventricular ejection fraction (LVEF), RAS blockade dose was identified as independent predictor for all-cause mortality (hazard ratio [HR] 0.72; 95% confidence interval [CI], 0.54-0.97; P = 0.03). With respect to LV remodelling, a significantly larger reduction of LV mass index was observed during the follow-up with higher doses of RAS blockade.ConclusionsThe current study showed that the impact of RAS blockade treatment on clinical outcome and LV remodelling after TAVR is dose dependent. 相似文献
105.
Marwin Bannehr Ulrike Kahn Josephin Liebchen Maki Okamoto Valentin Hähnel Christian Georgi Victoria Dworok Christoph Edlinger Michael Lichtenauer Tanja Kücken Siegfried Kropf Anja Haase-Fielitz Christian Butter 《The Canadian journal of cardiology》2021,37(7):1086-1093
BackgroundFunctional tricuspid regurgitation (TR) is a frequent finding in echocardiography. Despite general consent that right ventricular (RV) dysfunction impacts outcome of patients with TR, it is still unknown which echocardiographic parameters most accurately reflect prognosis. In this study we aimed to evaluate the prevalence of RV dysfunction and its prognostic value in patients with TR.MethodsData from 1089 consecutive patients were analysed. Tricuspid annular plane systolic excursion (TAPSE), fractional area change, and right ventricular free wall longitudinal strain (RV strain) were used to define RV dysfunction. Patients were followed for 2-year all-cause mortality. For prediction of survival, reclassification and C statistics of RV functional parameters using TR grade as reference model were performed.ResultsAmong the patients studied, 13.9% showed no TR, 61.2% had mild TR, 19.6% had moderate TR, and 5.3% had severe TR. The TR grade was associated with increased mortality (log rank, P < 0.001). Impaired RV strain and TAPSE were independent predictors for mortality (RV: hazard ratio [HR], 1.130; 95% confidence interval [CI], 1.099-1.160; P < 0.001; TAPSE: HR, 1.131; 95% CI, 1.085-1.175; P < 0.001). Both RV strain and TAPSE improved the reference model for survival prediction (RV: integrated discrimination improvement [IDI], 0.184; 95% CI, 0.146-0.221; P < 0.001; TAPSE: IDI, 0.057; 95% CI, 0.037-0.077; P < 0.001).ConclusionsEchocardiographic evaluation of RV function appears to useful for patients with TR. Assessment of RV strain provides additional value for prediction of 2-year mortality. 相似文献
106.
Adoptive immunotherapy in chimeras with donor lymphocytes 总被引:2,自引:0,他引:2
Kolb HJ Schmid C Chen X Woiciechowski A Roskrow M Weber M Guenther W Ledderose G Schleuning M 《Acta haematologica》2003,110(2-3):110-120
Allogeneic stem cell transplantation has a well-defined indication in the treatment of hematological malignancies. The beneficial immune effect of allogeneic marrow transplantation has long been known, but only recently have methods been developed to separate the graft-versus-leukemia (GVL) effect from graft-versus-host disease (GVHD). Animal experiments have shown that lymphocytes from the marrow donor can be transfused without causing severe GVHD if stable chimerism and tolerance is established. First clinical studies have been preformed in patients with recurrent chronic myelogenous leukemia. In these patients complete molecular remissions were induced that persist without further maintenance treatment. These results have been confirmed in larger multicenter studies in Europe and the USA. The best results were obtained in chronic myelogenous leukemia (CML); repeated successes have been reported in relapsing acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma (MMY), and rare responses were reported for acute lymphoid leukemia. Contrary to animal experiments GVHD has been observed in human patients although to a lesser extent than expected in transplants not given immunosuppression. Secondly myelosuppression has been observed in patients treated with relapsing CML. In CML the incidence of GVHD could be reduced by depleting CD8+ T cells from the donor lymphocyte concentrate. Alternatively only small numbers of T lymphocytes can be transfused and in the case of failing responses, the numbers of donor lymphocytes may be increased. Results in recurrent AML have been improved by the use of low-dose cytosine arabinoside, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor mobilized blood cells as compared to lymphocytes only. In MMY the response rate is higher than in AML, but the remissions are of limited duration in most patients. Several protocols have been designed to include preemptive donor lymphocyte transfusion in patients with a high relapse risk after transplantation. Problems remain to avoid chronic GVHD and to circumvent the immune escape mechanisms of leukemia. 相似文献
107.
108.
Karl Egerer Julia Hertzer Eugen Feist Anja Albrecht Paul Eberhard Rudolph Thomas Drner Gerd‐Rüdiger Burmester 《Arthritis care & research》2003,49(4):546-548
Objectives
To determine the usefulness of sE‐selectin as a marker for early diagnosis and stratification of rheumatoid arthritis.Methods
We investigated several markers of disease activity, including circulating adhesion molecules and other standard laboratory tests, in a 2–3 year followup analysis of patients with rheumatoid arthritis.Results
The mean ± SD levels of sE‐selectin (91.68 ± 31.8 ng/ml versus 49.83 ± 14.76 ng/ml) and rheumatoid factor (375.7 ± 394.4 U versus 44.66 ± 37.63 U) were strongly elevated in severe (n = 15) versus mild (n = 7) courses of disease. Statistical calculation of mean and standard deviation revealed that sE‐selectin represents a highly significant marker for the presence of persistent and aggressive disease over time, regardless of therapeutic intervention and observation time points (P = 0.0004). Notably, regression analysis identified constant values for all parameters analyzed and, therefore, a stable course of the disease could be predicted from the beginning.Conclusion
sE‐selectin appears to be a powerful marker to predict the severity of rheumatoid arthritis.109.
CC chemokine ligand 20 partially controls adhesion of naive B cells to activated endothelial cells under shear stress 总被引:2,自引:0,他引:2 下载免费PDF全文
Meissner A Zilles O Varona R Jozefowski K Ritter U Marquez G Hallmann R Korner H 《Blood》2003,102(8):2724-2727
Chemokines are thought to control lymphocyte recruitment to the inflamed endothelium. To dissect chemokine-mediated adhesion, binding of ex vivo isolated splenocytes to tumor necrosis factor (TNF)-activated endothelial cells was analyzed under shear stress. We observed specific adhesion of naive follicular B cells, which could be blocked by pertussis toxin. This indicated a G protein-mediated binding and pointed at a contribution of chemokine receptors to B-cell adhesion. Analysis of chemokines expressed by TNF-activated endothelial cells showed that CC chemokine ligand 2 (CCL2), CCL17, and CCL20 were up-regulated. Only on follicular B cells was the cognate receptor for CCL20, CC chemokine receptor 6 (CCR6), expressed strongly, and a functional transmigration assay with CCR6-negative B cells demonstrated conclusively the sole signaling of CCL20 through CCR6. Desensitization of CCR6 on naive B cells with CCL20 resulted in receptor down-regulation and reduced B-cell adhesion. We conclude that CCL20 plays a vital role in B-cell adhesion to the inflamed endothelium. 相似文献
110.
Karlotta Schloesser Yvonne Eisenmann Anja Bergmann Steffen T. Simon 《Journal of pain and symptom management》2021,61(5):963-973.e1
ContextEpisodic breathlessness is characterized by a severe worsening of breathlessness intensity that goes beyond usual fluctuations. Episodes are usually short; therefore, nonpharmacological strategies (cognitive and behavioral) seem most promising to be beneficial. Which strategies—delivered separately or in combination—might be most effective and feasible remains unclear.ObjectivesThe Delphi survey selects and determines different nonpharmacological strategies for coping with episodic breathlessness to develop a brief cognitive and behavioral intervention for the management of episodic breathlessness.MethodsUsing an online Delphi survey comprising three rounds, international, multidisciplinary experts in breathlessness summarized and determined cognitive and behavioral strategies. The a priori target agreement for close-ended questions was 70%.ResultsExperts (n = 41/87; n = 45/85; n = 36/85) agreed on 15 of the 31 cognitive and behavioral strategies. Based on the panellists' opinion, the final version of the cognitive and behavioral intervention comprised the following characteristics: individually tailored intervention, a high proportion of communication, short duration, the involvement of carers, and use of the Breathing, Thinking, Functioning Model of Spathis et al. Consensus upon the delivery of the subsequent strategies within the intervention was reached: handheld fan, forward lean, diaphragmatic breathing, distraction, pursed lips breathing, long breaths out, and relaxation training.ConclusionUsing the consented nonpharmacological strategies, a brief cognitive and behavioral intervention was developed that balances between individualization and standardization of the intervention. 相似文献