全文获取类型
收费全文 | 2490994篇 |
免费 | 182384篇 |
国内免费 | 3968篇 |
专业分类
耳鼻咽喉 | 33854篇 |
儿科学 | 82036篇 |
妇产科学 | 68437篇 |
基础医学 | 371046篇 |
口腔科学 | 71648篇 |
临床医学 | 222176篇 |
内科学 | 475134篇 |
皮肤病学 | 54362篇 |
神经病学 | 190659篇 |
特种医学 | 96988篇 |
外国民族医学 | 581篇 |
外科学 | 375028篇 |
综合类 | 56620篇 |
现状与发展 | 5篇 |
一般理论 | 770篇 |
预防医学 | 189384篇 |
眼科学 | 58008篇 |
药学 | 189043篇 |
6篇 | |
中国医学 | 5539篇 |
肿瘤学 | 136022篇 |
出版年
2018年 | 24682篇 |
2016年 | 21386篇 |
2015年 | 24293篇 |
2014年 | 33335篇 |
2013年 | 50390篇 |
2012年 | 68895篇 |
2011年 | 73515篇 |
2010年 | 43265篇 |
2009年 | 40664篇 |
2008年 | 69119篇 |
2007年 | 73734篇 |
2006年 | 74481篇 |
2005年 | 71613篇 |
2004年 | 70200篇 |
2003年 | 67180篇 |
2002年 | 65610篇 |
2001年 | 115070篇 |
2000年 | 118217篇 |
1999年 | 99668篇 |
1998年 | 27141篇 |
1997年 | 24053篇 |
1996年 | 24122篇 |
1995年 | 23287篇 |
1994年 | 21787篇 |
1993年 | 20448篇 |
1992年 | 80745篇 |
1991年 | 80077篇 |
1990年 | 78432篇 |
1989年 | 76527篇 |
1988年 | 70962篇 |
1987年 | 69693篇 |
1986年 | 66113篇 |
1985年 | 63576篇 |
1984年 | 47406篇 |
1983年 | 40663篇 |
1982年 | 23309篇 |
1981年 | 20878篇 |
1979年 | 45011篇 |
1978年 | 31446篇 |
1977年 | 26318篇 |
1976年 | 25463篇 |
1975年 | 27694篇 |
1974年 | 33243篇 |
1973年 | 31925篇 |
1972年 | 29587篇 |
1971年 | 27891篇 |
1970年 | 26075篇 |
1969年 | 24318篇 |
1968年 | 22460篇 |
1967年 | 20215篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
Rishad R. Jivani Gaurang J. Lakhtaria Dhaval D. Patadiya Laxman D. Patel Nurrudin P. Jivani Bhagyesh P. Jhala 《Saudi Pharmaceutical Journal》2016,24(1):1-20
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures. 相似文献
23.
M. R. D. Maslin S. K. Lloyd S. Rutherford S. Freeman A. King D. R. Moore K. J. Munro 《Journal of the Association for Research in Otolaryngology》2015,16(5):631-640
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis. 相似文献
24.
Xiaoyan Lu Isabelle R. Miousse Sandra V. Pirela Jodene K. Moore Stepan Melnyk 《Nanotoxicology》2016,10(5):629-639
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs. 相似文献
25.
26.
27.
F. Fruzzetti G. Palla A. Sbrana T. Simoncini M. R. Sessa 《Gynecological endocrinology》2020,36(10):938-940
AbstractObjective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings. 相似文献
28.
Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC50 value of 13.8?mg/mL on PLA2 from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC50 value of 16.6?mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC50 value of 0.92?mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of??128.96 compared to standard phenidone (?103.61). Thus, the current study validates the application of WS for inflammatory diseases.Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases. 相似文献
29.
Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study 下载免费PDF全文
30.