全文获取类型
收费全文 | 2212篇 |
免费 | 98篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 20篇 |
妇产科学 | 67篇 |
基础医学 | 280篇 |
口腔科学 | 17篇 |
临床医学 | 175篇 |
内科学 | 633篇 |
皮肤病学 | 20篇 |
神经病学 | 327篇 |
特种医学 | 36篇 |
外科学 | 237篇 |
综合类 | 16篇 |
一般理论 | 3篇 |
预防医学 | 104篇 |
眼科学 | 60篇 |
药学 | 168篇 |
中国医学 | 5篇 |
肿瘤学 | 123篇 |
出版年
2023年 | 5篇 |
2022年 | 56篇 |
2021年 | 100篇 |
2020年 | 18篇 |
2019年 | 17篇 |
2018年 | 49篇 |
2017年 | 33篇 |
2016年 | 29篇 |
2015年 | 50篇 |
2014年 | 68篇 |
2013年 | 81篇 |
2012年 | 149篇 |
2011年 | 183篇 |
2010年 | 93篇 |
2009年 | 67篇 |
2008年 | 118篇 |
2007年 | 187篇 |
2006年 | 162篇 |
2005年 | 158篇 |
2004年 | 137篇 |
2003年 | 143篇 |
2002年 | 132篇 |
2001年 | 9篇 |
2000年 | 15篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 19篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 15篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1967年 | 6篇 |
排序方式: 共有2318条查询结果,搜索用时 31 毫秒
81.
82.
Radiosynthesis of microtubule‐targeted theranostic methyl N‐[5‐(3’‐radiohalobenzoyl)‐1H‐benzimidazol‐2‐yl]carbamates 下载免费PDF全文
Zbigniew P. Kortylewicz Janina Baranowska‐Kortylewicz 《Journal of labelled compounds & radiopharmaceuticals》2018,61(10):749-756
Microtubules are a target for a broad spectrum of drugs used as chemotherapeutics to treat hematological malignancies and solid tumors. Most of these drugs have significant dose‐limiting toxicities including peripheral neuropathies that can be debilitating and permanent. In an ongoing effort to develop safer and more effective drugs, benzimidazole‐based compounds are being developed as replacement for vincristine and similar agents. In this report, we describe radiosyntheses of novel microtubule‐targeting methyl N‐[5‐(3’‐radiohalobenzoyl)‐1H‐benzimidazol‐2‐yl]carbamates 4 that are intended as potential imaging agents and molecular radiotherapeutics. 125I‐ and 131I‐radiolabeled derivatives were prepared either by direct radioiodination of methyl N‐(6‐benzoyl‐1H‐benzimidazol‐2‐yl)carbamate 1 or radioiododestannylation of the corresponding stannane precursor 3 . The direct radioiodination was conducted in a solution of 1 in triflic acid and produced after ~1 hour at elevated temperatures and HPLC purification on average 62% of the no‐carrier added products 125I‐ 4 and 131I‐ 4 . Radioiododestannylation of 3’‐trimethylstannane 3 proceeded with ease at room temperature in the presence of H2O2 as the oxidant and produced no‐carrier‐added 125I‐ 4 and 131I‐ 4 in high isolated yields, on average 85%. The radiohalodestannylation protocol is universal and can be applied to other radiohalides including 124I to produce 124I‐ 4 , a positron emission tomography agent, and 211At to produce 211At‐ 4 , an α‐particle emitting radiotherapeutic. 相似文献
83.
Kalarus Z Lenarczyk R Kowalski O Pruszkowska-Skrzep P Krupa H Sredniawa B Sokal A Zielińska T 《Pacing and clinical electrophysiology : PACE》2007,30(1):85-92
BACKGROUND: We sought to evaluate the influence of atrio-ventricular reentrant tachycardia (AVRT) on atrial pressures during tachycardia and the presence of atrial fibrillation (AF) in patients with preexcitation syndrome. METHODS: The study population consisted of 88 patients (37 females, mean age 37.3 years) with left-sided accessory pathway and AVRT induced during electrophysiologic study. The AF-inducible group consisted of 32 patients with sustained episodes of AF provoked during electrophysiologic study, whereas the noninducible group comprised 56 patients without AF. RESULTS: We found significantly higher values of maximal and mean left (LAP) and right (RAP) atrial pressures in the AF group compared with noninducible group: LAP max 32.0 versus 20.8, LAP mean 21.6 versus 13.2, RAP max 15.2 versus 11.5, RAP mean 8.2 versus 6.2 respectively (P < 0.001). When analyzing the effect of AVRT on atrial pressures, we found a significant (P < 0.001) negative correlation between anterograde conduction times during tachycardia and LAP max and LAP mean in the whole population, but a significant positive correlation between retrograde conduction time and left atrial pressures. Similar effects of AVRT on the right atrial pressures were found. CONCLUSIONS: Atrial pressures during AVRT, which depend on the electrophysiological features of tachycardia, play an important role in the genesis of atrial fibrillation in patients with preexcitation syndrome. 相似文献
84.
BACKGROUND: The tilt table test (TTT) is a useful diagnostic tool in people with unexplained syncope, dizziness, and falls. However, preexisting comorbidities and medications affecting hemodynamic response might affect TTT outcome (i.e. presence or absence of vasomotor syncope). We studied the influence of these compounding factors on TTT outcome. METHODS: One hundred and sixty-four elderly patients with a mean (+/-SD) age of 80.0 +/- 6.1 years (M:F 104:60) underwent TTT. Heart rate and blood pressure were recorded continuously using a noninvasive device (Task Force Monito, CNS systems, Graz, Austria). Predictors of TTT outcome in a backward regression analysis included age, gender, comorbidities (chronic heart failure, hypertension, diabetes, and cerebrovascular disease), and drugs (beta-blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, diuretics, digoxin, opioids, antidepressants, and nonsteroidal antiinflammatory agents). RESULTS: TTT was positive in 30 patients (18.3%). None of the above factors were a significant predictor of TTT outcome. The use of calcium channel blockers predicted a drop in systolic blood pressure after 2 minutes of TTT (P = 0.048, R(2)= 0.018). However, this was not associated with significant changes in heart rate and did not influence TTT outcome. CONCLUSION: The TTT outcome was not influenced by comorbidities or medications. TTT is a reliable diagnostic tool in a population characterized by significant comorbidities and polypharmacy. 相似文献
85.
Małgorzata Kiełczykowska Ewelina Kopciał Joanna Kocot Jacek Kurzepa Zbigniew Marzec Irena Musik 《Pharmacological reports : PR》2018,70(6):1168-1172
Background
Selenium is an essential element which shows protective properties against diverse harmful factors. Lithium compounds are widely used in medicine, but, in spite of undoubted beneficial effects, treatment with these compounds may lead to severe side effects, including renal, gastrointestinal, neurological, endocrine and metabolic disorders. This study was aimed at evaluating the influence of selenium and/or lithium on lithium, iron, zinc and copper content in rats’ erythrocytes as well as estimate the action of additional selenium on lithium exposure effects.Methods
The experiment was performed on four groups of rats (six animals each): control – received saline; Li – received 2.7 mg Li/kg b.w. as lithium carbonate; Se – received 0.5 mg Se/kg b.w. as sodium selenite; Se + Li – received simultaneously 0.5 mg Se/kg b.w. and 2.7 mg Li/kg b.w. (sodium selenite and lithium carbonate). The administration was performed for three weeks, once a day by stomach tube, in form of water solutions. In erythrocytes the content of lithium, iron, zinc and copper was determined using flame atomic absorption spectroscopy.Results
Lithium treatment insignificantly disturbed iron and zinc homeostasis as well as markedly increased lithium accumulation and copper content in rat erythrocytes. Selenium coadministration reversed those effects.Conclusions
The beneficial effect of selenium on disturbances of studied microelements homeostasis as well as on preventing lithium accumulation in erythrocytes in Li receiving animals allows suggesting that further research on selenium application as an adjuvant in lithium therapy is worth carrying on. 相似文献86.
87.
Andre C. Felicio MD PhD Katherine Dinelle MSc Pankaj A. Agarwal MD DNB DM Jessamyn McKenzie LPN Nicole Heffernan RN Jeremy D. Road MD Silke Appel‐Cresswell MD Zbigniew K. Wszolek MD Matthew J. Farrer PhD Michael Schulzer MD PhD Vesna Sossi PhD A. Jon Stoessl CM MD FRCPC 《Movement disorders》2014,29(9):1197-1201
88.
aneta Garczyk Zbigniew Jaegermann Piotr Duda Andrzej S. Swinarew Sebastian Stach 《Materials》2021,14(9)
The main aim of this study was to analyze microtomographic data to determine the geometric dimensions of a ceramic porous material’s internal structure. Samples of a porous corundum biomaterial were the research material. The samples were prepared by chemical foaming and were measured using an X-ray scanner. In the next stage, 3D images of the samples were generated and analyzed using Thermo Scientific Avizo software. The analysis enabled the isolation of individual pores. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The last part of the research consisted of verifying the developed method by comparing the obtained results with the parameters obtained from the microscopic examinations of the biomaterial. The comparison of the results confirmed the correctness of the developed method. The developed methodology can be used to analyze biomaterial samples to assess the geometric dimensions of biomaterial pores. 相似文献
89.
Zbigniew Kledyski Pawe Falaciski Agnieszka Machowska ukasz Szarek ukasz Krysiak 《Materials》2021,14(9)
Hardening slurries (water-bentonite-binder mixtures) constitute a well-established material used broadly, i.a., for cut-off walls in civil and water engineering. Although they usually contain Portland cement, similar to common concrete, their properties differ greatly, mostly due to a much higher water content. This characteristic of hardening slurries creates unique opportunities for the utilization of significant quantities of industrial by-products that are deemed problematic in the concrete industry. This article investigates the effect of the addition of by-products of fluidized-bed combustion of hard, brown coal and municipal sewage sludge, as well as ground granulated blast furnace slag, on the properties of slurries. Unconfined compressive strength tests, as well as mercury porosimetry, scanning electron microscopy, and X-ray diffraction analyses were performed. The results suggest that it is possible to design hardening slurry mixes of desired properties, both in liquid and solid state, containing at least 100–300 kg/m3 of industrial waste. This includes cement-free slurries based entirely on industrial by-products as binders. In addition, the analyzed slurries exhibited good chemical resistance to landfill eluates, at the same time effectively immobilizing heavy metals. It was concluded that hardening slurry technology can ensure the safe deposition of significant amounts of waste that would be otherwise difficult to manage, thus contributing to the circular economy concept. 相似文献
90.
Green electrospun materials are gaining popularity in the quest for a more sustainable environment for human life. Bee pollen (BP) is a valuable apitherapeutic product and has many beneficial features such as antioxidant and antibacterial properties. Alginate is a natural and low-cost polymer. Both natural materials show good compatibility with human tissues for biomedical applications and have no toxic effect on the environment. In this study, bee pollen-loaded sodium alginate and polyvinyl alcohol (SA/PVA) nanofibrous mats were fabricated by the electrospinning technique. The green electrospun nanofibrous mats were analyzed by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimeter (DSC). According to the findings of the study, the toxin-free electrospinning method is suitable for producing green nanomaterial. Because of the useful properties of the bee pollen and the favorable biocompatibility of the alginate fibers, the bee pollen-loaded SA/PVA electrospun mats have the potential for use in a variety of biomedical applications. 相似文献