全文获取类型
收费全文 | 36887篇 |
免费 | 1997篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 440篇 |
儿科学 | 2213篇 |
妇产科学 | 714篇 |
基础医学 | 4676篇 |
口腔科学 | 835篇 |
临床医学 | 2647篇 |
内科学 | 7499篇 |
皮肤病学 | 855篇 |
神经病学 | 1922篇 |
特种医学 | 1103篇 |
外科学 | 5018篇 |
综合类 | 1334篇 |
一般理论 | 15篇 |
预防医学 | 2129篇 |
眼科学 | 1547篇 |
药学 | 3521篇 |
中国医学 | 274篇 |
肿瘤学 | 2259篇 |
出版年
2023年 | 238篇 |
2022年 | 667篇 |
2021年 | 1163篇 |
2020年 | 640篇 |
2019年 | 860篇 |
2018年 | 1060篇 |
2017年 | 724篇 |
2016年 | 960篇 |
2015年 | 1005篇 |
2014年 | 1364篇 |
2013年 | 1768篇 |
2012年 | 2415篇 |
2011年 | 2435篇 |
2010年 | 1402篇 |
2009年 | 1258篇 |
2008年 | 1775篇 |
2007年 | 1764篇 |
2006年 | 1772篇 |
2005年 | 1399篇 |
2004年 | 1401篇 |
2003年 | 1184篇 |
2002年 | 1012篇 |
2001年 | 831篇 |
2000年 | 875篇 |
1999年 | 750篇 |
1998年 | 404篇 |
1997年 | 282篇 |
1996年 | 298篇 |
1995年 | 269篇 |
1994年 | 230篇 |
1993年 | 211篇 |
1992年 | 509篇 |
1991年 | 412篇 |
1990年 | 443篇 |
1989年 | 434篇 |
1988年 | 382篇 |
1987年 | 394篇 |
1986年 | 371篇 |
1985年 | 352篇 |
1984年 | 285篇 |
1983年 | 235篇 |
1982年 | 161篇 |
1979年 | 236篇 |
1978年 | 164篇 |
1977年 | 198篇 |
1975年 | 184篇 |
1974年 | 182篇 |
1973年 | 182篇 |
1972年 | 173篇 |
1971年 | 161篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Thermal unfolding and refolding of a lytic polysaccharide monooxygenase from Thermoascus aurantiacus
Raushan K. Singh Benedikt M. Blossom D. A. Russo B. van Oort R. Croce P. E. Jensen C. Felby M. J. Bjerrum 《RSC advances》2019,9(51):29734
Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes which promote the degradation of recalcitrant polysaccharides like cellulose or chitin. Here, we have investigated the thermostability of an LPMO from Thermoascus aurantiacus (TaLPMO9A). TaLPMO9A was found to retain most of its initial activity after incubating at 100 °C while its apparent melting temperature (Tm) is 69 °C at neutral pH. Interestingly, our studies show that holoTaLPMO9A, apoTaLPMO9A and deglycosylated TaLPMO9A can fold back to their original conformation upon lowering the temperature. In the presence of β-mercaptoethanol the protein does not refold. Activity of TaLPMO9A and refolded TaLPMO9A was studied by an Amplex® Red assay as well as by TaLPMO9A catalysed oxidation of phosphoric acid swollen cellulose (PASC). These studies confirm the functional regain of TaLPMO9A activity upon going through one cycle of unfolding and refolding. The thermal unfolding and refolding of TaLPMO9A was measured spectroscopically. Utilizing the two-state model, detailed thermodynamic parameters were obtained for holoTaLPMO. Furthermore, we have investigated the kinetics of TaLPMO9A unfolding and refolding. Our results have implications in understanding LPMO stability, which is crucial for the efficient application of LPMOs as biocatalysts during biomass degradation.TaLPMO9A regains its catalytic power after a thermal unfolding and refolding cycle. 相似文献
992.
993.
Background
Wound myiasis in the Indian subcontinent is most commonly caused by old world screw-worm (Chrysomya bezziana).Case Report and management
A 4-yearold malnourished girl presented with full thickness rectal prolapse following acute diarrhea with a large wound and screwworm myiasis of the rectum. Turpentine oil was applied to immobilize the maggots followed by manual extraction. Prolapse was successfully treated by manual reduction followed by strapping of the buttocks.Outcome
Child was thriving well and gained 2 kg weight in follow up after two weeks.Message
Parents should be educated about taking care of prolapsed rectum. 相似文献994.
995.
4D printed objects are indexed under additive manufacturing (AM) objects. The 4D printed materials are stimulus-responsive and have shape-changing features. However, the manufacturing of such objects is still a challenging task. For this, the designing space has to be explored in the initial stages, which is lagging so far. This paper encompasses two recent approaches to explore the conceptual design of 4D printed objects in detail: (a) an application-based modeling and simulation approach for phytomimetic structures and (b) a voxel-based modeling and simulation approach. The voxel-based modeling and simulation approach has the enhanced features for the rapid testing (prior to moving into design procedures) of the given distribution of such 4D printed smart materials (SMs) while checking for behaviors, particularly when these intelligent materials are exposed to a stimulus. The voxel-based modeling and simulation approach is further modified using bi-exponential expressions to encode the time-dependent behavior of the bio-inspired 4D printed materials. The shape-changing materials are inspired from biological objects, such as flowers, which are temperature-sensitive or touch-sensitive, and can be 4D printed in such a way that they are encrypted with a decentralized, anisotropic enlargement feature under a restrained alignment of cellulose fibers as in the case of composite hydrogels. Such plant-inspired architectures can change shapes when immersed in water. This paper also outlines a review of the 4D printing of (a) smart photocurable and biocompatible scaffolds with renewable plant oils, which can be a better alternative to traditional polyethylene glycol diacrylate (PEGDA) to support human bone marrow mesenchymal stem cells (hMSCs), and (b) a biomimetic dual shape-changing tube having applications in biomedical engineering as a bioimplant. The future applications would be based on these smart and intelligent materials; thus, it is important to modify the existing voxel-based modeling and simulation approach and discuss efficient printing methods to fabricate such bio-inspired materials.4D printed objects are indexed under additive manufacturing (AM) objects. 相似文献
996.
A. R. Pradeep Santosh S. Martande Sonender Pal Singh Deepak Kumar Suke Arjun P. Raju Savitha B. Naik 《Inflammation research》2014,63(4):317-323
Objective
The aim of the present study was to evaluate the levels and correlation of human S100A12 and high-sensitivity C-reactive protein (hs-CRP) in gingival crevicular fluid (GCF) and serum in chronic periodontitis (CP) subjects with and without type 2 diabetes mellitus (DM).Materials and methods
A total of 44 subjects were divided into three groups: group 1 had 10 periodontally healthy subjects, group 2 consisted of 17 CP subjects and group 3 had 17 type 2 DM subjects with CP. GCF and serum levels of human S100A12 and hs-CRP were quantified using enzyme-linked immunosorbent assay and immunoturbidimetric analysis, respectively. The clinical outcomes evaluated were gingival index, probing depth and clinical attachment level and the correlations of the two inflammatory mediators with clinical parameters were evaluated.Results
Both human S100A12 and hs-CRP levels increased from group 1 to group 2 to group 3. The GCF and serum values of both these inflammatory mediators correlated positively with each other and with the periodontal parameters evaluated (p < 0.05).Conclusion
Human S100A12 and hs-CRP can be considered as possible GCF and serum markers of inflammatory activity in CP and DM. 相似文献997.
Gilles Morin Nadina Ortiz Bruechle Amrathlal Rabbind Singh Cordula Knopp Guillaume Jedraszak Miriam Elbracht Dominique Brémond‐Gignac Kathi Hartmann Henri Sevestre Peter Deutz Didier Hérent Peter Nürnberg Bernard Roméo Kerstin Konrad Michèle Mathieu‐Dramard Johannes Oldenburg Elisabeth Bourges‐Petit Yuequan Shen Klaus Zerres Halima Ouadid‐Ahidouch Jacques Rochette 《Human mutation》2014,35(10):1221-1232
Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole‐exome sequencing, we identified the c.910C > T transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca2+ sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca2+ levels and store‐operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single‐gene defect, which is consistent with Mendelian‐dominant inheritance. 相似文献
998.
Gilles Morin Nadina Ortiz Bruechle Amrathlal Rabbind Singh Cordula Knopp Guillaume Jedraszak Miriam Elbracht Dominique Brémond‐Gignac Kathi Hartmann Henri Sevestre Peter Deutz Didier Hérent Peter Nürnberg Bernard Roméo Kerstin Konrad Michèle Mathieu‐Dramard Johannes Oldenburg Elisabeth Bourges‐Petit Yuequan Shen Klaus Zerres Halima Ouadid‐Ahidouch Jacques Rochette 《Human mutation》2014,35(12):1542-1542
999.
Pankaj Gupta Yashi Marodia Akash Bansal Naveen Kalra Praveen Kumar-M Vishal Sharma Usha Dutta Manavjit Singh Sandhu 《World journal of gastroenterology : WJG》2020,26(40):6163-6181
Gallbladder(GB) wall thickening is a frequent finding caused by a spectrum of conditions. It is observed in many extracholecystic as well as intrinsic GB conditions. GB wall thickening can either be diffuse or focal. Diffuse wall thickening is a secondary occurrence in both extrinsic and intrinsic pathologies of GB, whereas, focal wall thickening is mostly associated with intrinsic GB pathologies. In the absence of specific clinical features, accurate etiological diagnosis can be challenging. The survival rate in GB carcinoma(GBC) can be improved if it is diagnosed at an early stage, especially when the tumor is confined to the wall. The pattern of wall thickening in GBC is often confused with benign diseases, especially chronic cholecystitis, xanthogranulomatous cholecystitis, and adenomyomatosis. Early recognition and differentiation of these conditions can improve the prognosis. In this minireview, the authors describe the patterns of abnormalities on various imaging modalities(conventional as well as advanced) for the diagnosis of GB wall thickening. This paper also illustrates an algorithmic approach for the etiological diagnosis of GB wall thickening and suggests a formatted reporting for GB wall abnormalities. 相似文献
1000.
Sharanpreet Singh Jaswinder Singh Amandeep Kaur Jagroop Kaur Adarsh Pal Vig Sartaj Ahmad Bhat 《Sustainable Chemistry and Pharmacy》2019
Pigeon dropping is a kind of organic waste which can be transformed easily into organic manure by vermicomposting with exotic earthworm Eisenia fetida. In the present study, a pigeon excreta was collected from roof tops. The pigeon excreta was mixed with cattle dung with the ratios as 10%, 20%, 30%, 40% and 50% respectively, in plastic containers; meanwhile, those proposal were name as C10, C20, C30, C40 and C50 respectively. Feed mixtures were allowed to decompose (pre-vermicomposting without earthworm) for 20–25 days. After decomposition, 20 hatchlings of E. fetida were put in each concentration after weighing. Cattle dung (without pigeon excreta) was kept as the control. The physico-chemical analysis of initial feed mixture and final product after vermicomposting was also done to measure the changes in the feed mixtures from the initial to the final states. There were increases in the content of N (52.35%), P (115.79%), K (39.97%) and EC (56.16%) but decrease in those of OC (-15.49%), OM (-15.49%), pH (-7.92%) and Ca (-39.62%) from the initial to the final product. The highest population size of earthworms and minimum mortality rate was observed in C30 feed mixture. Thus, the present study indicated that cattle dung mixed with 30% (w/w) pigeon excreta waste may be a good choice for vermicomposting. 相似文献