首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1372篇
  免费   67篇
  国内免费   4篇
耳鼻咽喉   17篇
儿科学   97篇
妇产科学   26篇
基础医学   195篇
口腔科学   27篇
临床医学   148篇
内科学   224篇
皮肤病学   25篇
神经病学   67篇
特种医学   39篇
外国民族医学   1篇
外科学   118篇
综合类   36篇
一般理论   1篇
预防医学   101篇
眼科学   62篇
药学   124篇
中国医学   7篇
肿瘤学   128篇
  2024年   1篇
  2023年   16篇
  2022年   39篇
  2021年   68篇
  2020年   33篇
  2019年   45篇
  2018年   44篇
  2017年   35篇
  2016年   46篇
  2015年   44篇
  2014年   67篇
  2013年   93篇
  2012年   136篇
  2011年   122篇
  2010年   63篇
  2009年   41篇
  2008年   85篇
  2007年   89篇
  2006年   77篇
  2005年   54篇
  2004年   71篇
  2003年   49篇
  2002年   61篇
  2001年   7篇
  2000年   5篇
  1999年   4篇
  1998年   8篇
  1997年   5篇
  1996年   3篇
  1995年   1篇
  1994年   4篇
  1993年   6篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1987年   3篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1948年   1篇
  1930年   1篇
  1929年   1篇
  1922年   1篇
排序方式: 共有1443条查询结果,搜索用时 15 毫秒
11.
This article shows the results of experiments to grow Nitrogen incorporated ultrananocrystalline diamond (N-UNCD) films on commercial natural graphite (NG)/Cu anodes by hot chemical vapor deposition (HFCVD) using a gas mixture of Ar/CH4/N2/H2. The experiments focused on studying the effect of the pressure in the HFCVD chamber, filament-substrate distance, and temperature of the substrate. It was found that a substrate distance of 3.0 cm and a substrate temperature of 575 C were optimal to grow N-UNCD film on the graphite surface as determined by Raman spectroscopy, SEM, and TEM imaging. XPS analysis shows N incorporation through the film. Subsequently, the substrate surface temperature was increased using a heater, while keeping the substrate-filament distance constant at 3.0 cm. In this case, Raman spectra and SEM images of the substrate surface showed a major composition of graphite in the film as the substrate-surface temperature increased. Finally, the process pressure was increased to 10 Torr where it was seen that the growth of N-UNCD film occurred at 2.0 cm at a substrate temperature of 675 C. These results suggest that as the process pressure increases a smaller substrate-filament distance and consequently a higher substrate surface temperature can still enable the N-UNCD film growth by HFCVD. This effect is explained by a mean free path analysis of the main precursors H2 and CH3 molecules traveling from the filament to the surface of the substrate The potential impact of the process developed to grow electrically conductive N-UNCD films using the relatively low-cost HFCVD process is that this process can be used to grow N-UNCD films on commercial NG/Cu anodes for Li-ion batteries (LIBs), to enable longer stable capacity energy vs. charge/discharge cycles.  相似文献   
12.
The self-assembly of proteins is crucial in many biomedical applications. This work deals with understanding the role of cold atmospheric plasma (CAP) on the self-assembly of two different proteins present in the serum – BSA and hemoglobin and to elucidate the process associated with the direct application of physical plasma on or in the human (or animal) body, which has implications in therapeutics. The work has been corroborated by several spectroscopic studies such as fluorescence spectroscopy, circular dichroism spectroscopy, and SEM analysis. Through steady-state fluorescence spectroscopy and by following the tryptophan fluorescence, we observed that the emission intensity was quenched for the protein when treated with plasma radiation. Circular dichroism spectroscopy revealed that the structure of the protein was altered both in the case of BSA and hemoglobin. N-Acetyl tryptophanamide (NATA), which resembles the tryptophan in the protein, was treated with CAP and we observed the similar quenching of fluorescence as in the proteins, indicating that the protein underwent self-assembly. Time-resolved fluorescence spectroscopy with a decrease in the lifetime revealed that the protein self-assembly was promoted with CAP treatment, which was also substantiated by SEM micrographs. The ROS/RNS produced in the CAP has been correlated with the protein self-assembly. This work will help to design protein self-assembled systems, and in the future, may bring possibilities of creating novel biomaterials with the help of plasma radiation.

Self-assembly of proteins after CAP treatment.  相似文献   
13.
14.
15.
16.
We are presenting a rare case of toxoplasma lymphadenopathy with hyper viscosity syndrome due to polyclonal gammopathy. A 30 year old female presented with generalized lymphadenopathy. Lymph node biopsy findings suggestive of toxoplasmosis were confirmed on serology. Bone marrow aspiration showed 50 % plasma cells. On serum electrophoresis broad, diffuse band noted, indicative of polyclonal gammopathy. M band was absent. The patient was immunocompetent and presented with hyper viscosity syndrome masking the symptoms of underlying toxoplasmosis.  相似文献   
17.
We describe a 77‐year‐old female with hypertrophic cardiomyopathy in whom live/real time three‐dimensional transesophageal echocardiography (3DTEE) provided incremental value over two‐dimensional transthoracic and transesophageal echocardiography (2DTTE, 2DTEE) and three‐dimensional transthoracic echocardiography (3DTTE) in making a more comprehensive assessment and a more confident diagnosis of caseous mitral annular calcification. 3DTEE revealed a portion of the mass to consist of small, multiple, highly echogenic discrete band‐like and punctate areas within a relatively much less echogenic stroma and surrounded by a well defined highly echogenic border. This appearance correlated with the pathological findings of calcific granules/strands located in a liquefied or semiliquefied interior providing a typical toothpaste like appearance. The highly echogenic outer border represented the residual outer portion or rim of the calcific mass which did not undergo liquefaction. These findings on 3DTEE which correlated with the toothpaste like appearance seen at surgery were not visualized on 2DTTE, 2DTEE, and 3DTTE. (Echocardiography 2010;27:1147‐1150)  相似文献   
18.

Objectives

To identify clinically actionable genetic variants from targeted sequencing of 68 disease-related genes, estimate their penetrance, and assess the impact of disclosing results to participants and providers.

Patients and Methods

The Return of Actionable Variants Empirical (RAVE) Study investigates outcomes following the return of pathogenic/likely pathogenic (P/LP) variants in 68 disease-related genes. The study was initiated in December 2016 and is ongoing. Targeted sequencing was performed in 2533 individuals with hyperlipidemia or colon polyps. The electronic health records (EHRs) of participants carrying P/LP variants in 36 cardiovascular disease (CVD) genes were manually reviewed to ascertain the presence of relevant traits. Clinical outcomes, health care utilization, family communication, and ethical and psychosocial implications of disclosure of genomic results are being assessed by surveys, telephone interviews, and EHR review.

Results

Of 29,208 variants in the 68 genes, 1915 were rare (frequency <1%) and putatively functional, and 102 of these (60 in 36 CVD genes) were labeled P/LP based on the American College of Medical Genetics and Genomics framework. Manual review of the EHRs of participants (n=73 with P/LP variants in CVD genes) revealed that 33 had the expected trait(s); however, only 6 of 45 participants with non–familial hypercholesterolemia (FH) P/LP variants had the expected traits.

Conclusion

Expected traits were present in 13% of participants with P/LP variants in non-FH CVD genes, suggesting low penetrance; this estimate may change with additional testing performed as part of the clinical evaluation. Ongoing analyses of the RAVE Study will inform best practices for genomic medicine.  相似文献   
19.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Mutations in human flavin monooxygenase-3 (hFMO3) enzyme have been implicated in the rare autosomal recessive...  相似文献   
20.
Amoebiasis is a parasitic infectious disease caused by the enteric protozoan Entamoeba histolytica, a leading basis of deaths accounted to parasites, succeeding malaria and schistosomiasis. Conventional treatment methodologies used to deal with amoebiasis mainly rely on the administration of anti‐amoebic compounds and vaccines but are often linked with substantial side‐effects on the patient. Besides, cases of development of drug resistance in protozoans have been recorded, contributing further to the reduction in the efficiency of the treatment. Loopholes in the efficacious management of the disease call for the development of novel methodologies to manage amoebiasis. A way to achieve this is by targeting the essential metabolic processes of ‘encystation’ and ‘excystation’, and the associated biomolecules, thus interrupting the biphasic life cycle of the parasite. Technologies like the CRISPR‐Cas9 system can efficiently be exploited to discover novel and essential molecules that regulate the protozoan's metabolism, while efficiently manipulating and managing the known drug targets, leading to an effective halt and forestall to the enteric infection. This review presents a perspective on these essential metabolic processes and the associated molecules that can be targeted efficaciously to prevent the transmission of amoebiasis, thus managing the disease and proving to be a fruitful endeavour.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号