全文获取类型
收费全文 | 18697篇 |
免费 | 1094篇 |
国内免费 | 599篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 134篇 |
妇产科学 | 2130篇 |
基础医学 | 2520篇 |
口腔科学 | 536篇 |
临床医学 | 997篇 |
内科学 | 1392篇 |
皮肤病学 | 242篇 |
神经病学 | 1312篇 |
特种医学 | 435篇 |
外国民族医学 | 2篇 |
外科学 | 1438篇 |
综合类 | 2413篇 |
现状与发展 | 2篇 |
一般理论 | 2篇 |
预防医学 | 1033篇 |
眼科学 | 171篇 |
药学 | 3818篇 |
2篇 | |
中国医学 | 990篇 |
肿瘤学 | 715篇 |
出版年
2024年 | 15篇 |
2023年 | 123篇 |
2022年 | 210篇 |
2021年 | 417篇 |
2020年 | 345篇 |
2019年 | 324篇 |
2018年 | 373篇 |
2017年 | 415篇 |
2016年 | 461篇 |
2015年 | 426篇 |
2014年 | 871篇 |
2013年 | 1368篇 |
2012年 | 975篇 |
2011年 | 1250篇 |
2010年 | 1049篇 |
2009年 | 972篇 |
2008年 | 929篇 |
2007年 | 964篇 |
2006年 | 888篇 |
2005年 | 811篇 |
2004年 | 721篇 |
2003年 | 697篇 |
2002年 | 560篇 |
2001年 | 521篇 |
2000年 | 458篇 |
1999年 | 431篇 |
1998年 | 424篇 |
1997年 | 375篇 |
1996年 | 300篇 |
1995年 | 332篇 |
1994年 | 275篇 |
1993年 | 269篇 |
1992年 | 234篇 |
1991年 | 217篇 |
1990年 | 192篇 |
1989年 | 188篇 |
1988年 | 128篇 |
1987年 | 121篇 |
1986年 | 131篇 |
1985年 | 127篇 |
1984年 | 113篇 |
1983年 | 58篇 |
1982年 | 67篇 |
1981年 | 53篇 |
1980年 | 56篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1977年 | 25篇 |
1976年 | 17篇 |
1972年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The characteristics and distribution of muscarinic acetylcholine (mACh) receptor binding in primary somatosensory (SI) cortex and the caudate nucleus of raccoons were studied using [3H]-QNB, a muscarinic antagonist. The binding characteristics were similar to reported values in rat and cat. Autoradiographs produced from tissue sections labeled with [3H]-QNB showed the distribution of mACh receptors in the forebrain of the raccoon. [3H]-QNB binding was highest in cerebral cortex, neostriatum and hippocampus. Within SI cortex, binding was high in layers I-III and VI and relatively low in layers IV and V. Autoradiographs obtained from animals that had undergone peripheral deafferentation of part of the forepaw revealed no changes in [3H]-QNB binding in the affected cortical region during the time that physiological reorganization is known to occur. 相似文献
82.
A. J. Ferdous S. N. Islam M. Ahsan C. M. Hasan Z. U. Ahmed 《Phytotherapy research : PTR》1992,6(3):137-140
The antibacterial activity of the volatile oil of Nigella sativa seeds was studied against 37 isolates of Shigella dysenteriae 1, Shigella flexneri, Shigella sonnei and Shigella boydii and 10 strains of Vibrio cholerae and Escherichia coli. Most of the strains were clinically resistant to ampicillin, co-trimoxazole and tetracycline. All the strains tested showed promising sensitivity to the volatile oil. The minimum inhibitory concentration (MIC) of the volatile oil for Shigella, Vibrio and Escherichia strains tested was between 50–400 μg/mL. 相似文献
83.
The present investigation introduces an in vitro model to study macrophage properties during demyelination. Rat dorsal root ganglia (DRG) were cultured for obtaining myelinated peripheral nerve fibers. These cultures were exposed to non-resident macrophages. In untreated control cultures, there was no indication of myelin removal by the added macrophages. DRG were exposed to enzymatically generated oxygen radicals using the xanthin/xanthin oxidase or the glucose/glucose oxidase system. Assessment of Schwann cell viability and ultrastructural morphology revealed different patterns of cell cytotoxicity and morphological changes in different experiments. High concentrations caused complete tissue necrosis of the DRG, while low concentrations did not affect either cell viability or ultrastructural morphology. Under intermediate experimental conditions, oxygen radicals caused non-lethal Schwann cell damage leading to Schwann cell retraction and myelin sheath rejection. Myelin lamellae were disrupted and decompacted. These changes were followed by a selective macrophage attack on myelin sheats, resulting in demyelination. Axons, Schwann cells and sensory ganglion cells survived this attack. The specificity of the oxygen radical effects was tested in experiments using the oxygen radical scavengers catalase and superoxide dismutase. Catalase prevented the described effects on cell morphology and subsequently blocked demyelination by non-resident macrophages.Supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) (Br 1274/1-1) 相似文献
84.
S. Savi M. Savi S. Tamburi G. Vuleta S. Vesi C.C. Müller-Goymann 《European journal of pharmaceutical sciences》2007,30(5):441-450
There is a growing need for research into new skin- and environment-friendly surfactants. This paper focuses on a natural surfactant of an alkylpolyglucoside type, which can form both thermotropic and lyotropic liquid-crystalline phases. The aim of this study was to relate some physicochemical properties (characterised by polarisation and transmission electron microscopy, thermal analysis and rheology) of the three formulations based on cetearyl glucoside and cetearyl alcohol, to the results of in vitro and in vivo bioavailability of hydrocortisone (HC). The three formulations contained oils of different polarity (medium chain triglycerides: MG, isopropyl myristate: IPM and light liquid paraffin: LP), respectively. In vitro permeation was followed through the artificial skin constructs (ASC), while the parameters measured in vivo were erythema index: EI (using instrumental human skin blanching assay), transepidermal water loss (TEWL) and stratum corneum hydration (SCH). The vehicles based on cetearyl glucoside and cetearyl alcohol showed a complex colloidal structure of lamellar liquid-crystalline and lamellar gel-crystalline type, depending on oil polarity. Rheological profile of the vehicle was directly related to the in vitro profile of the HC permeation. In vivo results suggested that the vehicle with MG retarded the HC permeation, whereas less polar IPM and non-polar LP enhanced it. It is suggested that the enhancement is achieved either by a direct interaction with lipid lamellae of the SC or indirectly by improving skin hydration.
There were no adverse effects during in vivo study, which indicates a good safety profile of this alkylpolyglucoside surfactant. 相似文献
85.
达菲林在体外受精-胚胎移植中的应用 总被引:1,自引:1,他引:0
目的:观察达菲林在体外受精-胚胎移植中的疗效。方法:根据112例不孕患者用药前窦卵泡的数目采用不同剂量的达菲林降调节,常规超促排卵至卵泡成熟后,经阴道B超引导下取卵,行实验室体外培养受精,优质胚胎移植。结果:3组获卵数、获得的Ⅰ级胚胎数、胚胎移植后临床妊娠率、卵巢过度刺激综合征发生率等均无明显差异,受精率皆在70%以上,卵裂率在93%以上。结论:不同剂量的达菲林降调节均可获得高质量的卵子,且是一种肌肉注射缓释剂,易被患者接受。 相似文献
86.
M Buchelt H P Kutschera T Katterschafka H Kiss B Schneider R Ullrich 《Lasers in surgery and medicine》1992,12(4):375-381
Erb:YAG and Hol:YAG laser ablation rates of fibrocartilage and nucleus pulposus were measured in vitro simulating clinical conditions. After ablation macroscopic and microscopic appearance of the ablation site was investigated. Hol:YAG and Erb:YAG laser mean ablation rates increased almost linearly with rising energies, showing higher total ablation rates for the Hol:YAG laser due to its higher achievable energy density. At comparable energy densities the Erb:YAG laser appears to be more effective with respect to the corresponding ablation rates. Consequently, the ablational threshold proved to be lower for the Erb:YAG laser. Whereas during Hol:YAG laser ablation, some smoke formation and considerable tissue shrinking occurred, these effects could not be observed during Erb:YAG laser ablation. Consequently macroscopic and microscopic inspection showed some thermal damage after Hol:YAG and only minimal alterations after Erb:YAG laser ablation. Adjacent thermal damage was determined and proved to be lower for the Erb:YAG laser. In our opinion the characteristics of each laser system provide certain advantages for special clinical indications. 相似文献
87.
J.-L. Goëb S. Férel† J. Guetta P. Dutilh E. Dulioust J. Guibert A. Devaux G. Feldmann A. Guedeney P. Jouannet B. Golse 《Annales médico-psychologiques》2006,164(9):781-788
Assisted Reproductive Technologies (ART) come along with important emotional and psychological burden, as well as the physical constraints, for both the woman and her partner. Couples entering ART programs are usually infertile ones, but some specific settings, like serodiscordant couples where the male partner is HIV positive, involving fertile couples. These couples are usually well-adjusted and motivated ones. During the treatments, waiting for the outcome, and the unsuccessful cycles are among the most stressfull experiences. Common reactions are stress, anxiety and depression, but for some couples, the difficulties are so great that they discontinue the program after only one attempt. When parents, the couples usually experience good parenting competencies, and the “precious” children, despite a greater genetic risk, usually have a normal development, but some specific psychological difficulties may arise, that may request a specific help. 相似文献
88.
通过介绍国外人体骨铅测量的历史背景、多种器官铅含量的对比以及体内X射线荧光技术(In vivoXRF)测定骨铅研究的近期发展状况,探讨人体骨铅含量体内X射线荧光非损伤性测定的重要意义。 相似文献
89.
根管细菌渗漏体外模型的建立 总被引:1,自引:0,他引:1
目的:建立检测微细菌培养模型,以用于评价根管充填封闭情况。方法:牙根的冠根两端各连接一细菌培养储室,冠方储室置1mL无菌培养基并接种0.1mL菌液,根方储室起始为无菌培养基。每隔3d将冠方储室中菌液吸出1mL,并注入1mL新鲜BHI培养基,共90d。当根尖储室中培养基发生浑浊即为细菌渗漏发生,记录细菌渗漏发生时的天数。选择18个直根管前牙,其中牙胶充填组6个,用冷牙胶侧方加压充填技术充填;空管组6个,根管只预备不充填;根管密封组6个,根管充填并严密封闭根管口和根尖孔。用设计的模型检测密封状况。结果:全部空管组6个样本在1d内根方储室中出现浑浊;根管密封组6个样本的根方储室在90d内均未发生浑浊。牙胶充填组有2个样本分别在44d和46d发生浑浊。结论:此模型方法简单易行且实用有效,具有一定的临床相关性和可行性。 相似文献
90.
Sofia Avnet Annavera Lamolinara Nicoletta Zini Liliana Solimando Gianni Quacquaruccio Donatella Granchi Nadir Mario Maraldi Armando Giunti Nicola Baldini 《Journal of orthopaedic research》2006,24(8):1699-1708
Cathepsin K is a cystein protease that displays a proteolytic activity against Type I collagen and is abundantly and selectively expressed in osteoclasts where it plays a critical role in bone degradation. Its direct role in bone tissue has been defined by knock-out mice studies and inhibiting strategies in animals models. However, direct proof of cathepsin K function in human osteoclast model in vitro is lacking. The aim of this study is to analyze cathepsin K expression and localization in human osteoclasts obtained from peripheral blood and to examine cathepsin K function in these cells by antisense oligodeoxynucleotide (AS-ODN) strategy. AS-ODN was added to the culture of osteoclast precursors induced to differentiate by RANKL and M-CSF. AS-ODN treatment produced a significant down-regulation of cathepsin K mRNA (>80%) and protein expression, as verified respectively by Real-time PCR and by immunocytochemistry or Western blot. The cathepsin K inhibition caused an impairment of resorption activity as evaluated by a pit formation assay ( p = 0.045) and by electron microscopy, while the acidification process was unaffected. We demonstrated that antisense strategies against cathepsin K are selectively effective to inhibit resorption activity in human osteoclasts, like in animal models. 相似文献