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   39215篇
  免费   2130篇
  国内免费   133篇
耳鼻咽喉   536篇
儿科学   2602篇
妇产科学   697篇
基础医学   4702篇
口腔科学   1109篇
临床医学   2334篇
内科学   7040篇
皮肤病学   1151篇
神经病学   2376篇
特种医学   1188篇
外科学   6080篇
综合类   1276篇
一般理论   19篇
预防医学   1985篇
眼科学   1396篇
药学   4059篇
中国医学   340篇
肿瘤学   2588篇
  2023年   296篇
  2022年   342篇
  2021年   1136篇
  2020年   796篇
  2019年   908篇
  2018年   1334篇
  2017年   1041篇
  2016年   1333篇
  2015年   1382篇
  2014年   2022篇
  2013年   2301篇
  2012年   3257篇
  2011年   3165篇
  2010年   1882篇
  2009年   1476篇
  2008年   2132篇
  2007年   2132篇
  2006年   1926篇
  2005年   1704篇
  2004年   1597篇
  2003年   1343篇
  2002年   1131篇
  2001年   771篇
  2000年   704篇
  1999年   579篇
  1998年   236篇
  1997年   194篇
  1996年   193篇
  1995年   184篇
  1994年   155篇
  1993年   130篇
  1992年   348篇
  1991年   335篇
  1990年   357篇
  1989年   329篇
  1988年   285篇
  1987年   240篇
  1986年   234篇
  1985年   228篇
  1984年   173篇
  1983年   122篇
  1982年   68篇
  1981年   74篇
  1980年   66篇
  1979年   109篇
  1978年   71篇
  1977年   87篇
  1976年   65篇
  1973年   62篇
  1971年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The coronavirus disease 2019 (COVID-19) pandemic continues to be a global problem with over 438 million cases reported so far. Although it mostly affects the respiratory system, the involvement of extrapulmonary organs, including the liver, is not uncommon. Since the beginning of the pandemic, metabolic com-orbidities, such as obesity, diabetes, hypertension, and dyslipidemia, have been identified as poor prognostic indicators. Subsequent metabolic and lipidomic studies have identified several metabolic dysfunctions in patients with COVID-19. The metabolic alterations appear to be linked to the course of the disease and inflammatory reaction in the body. The liver is an important organ with high metabolic activity, and a significant proportion of COVID-19 patients have metabolic comorbidities; thus, this factor could play a key role in orchestrating systemic metabolic changes during infection. Evidence suggests that metabolic dysregulation in COVID-19 has both short- and long-term metabolic implications. Furthermore, COVID-19 has adverse associations with metabolic-associated fatty liver disease. Due to the ensuing effects on the renin-angiotensin-aldosterone system and ammonia metabolism, COVID-19 can have significant implications in patients with advanced chronic liver disease. A thorough understanding of COVID-19-associated metabolic dysfunction could lead to the identification of important plasma biomarkers and novel treatment targets. In this review, we discuss the current understanding of metabolic dysfunction in COVID-19, focusing on the liver and exploring the underlying mechanistic pathogenesis and clinical implications.  相似文献   
2.
3.
4.
Background: The current disadvantages (high cost, toxicity, resistance) of chemotherapy for gastric cancer opted people for alternative therapy from natural source. Curcumin (natural product) possess multiple biological activities but low bio-availability limits their uses as therapeutic. The Nano-formulation of curcumin increased the bioavailability and productivity of anti-cancer and anti-bacterial properties. The present study was initiated to determine the anti-cancer and anti-bacterial effect of Nano curcumin against gastric cancer and H. pylori. Methods: Curcumin loaded PLGA nanoparticles (CUR-NPs) was prepared by single emulsion solvent evaporation method. The MIC were determined using agar dilution method to find the anti-H. Pylori activity of Nano curcumin. The cytotoxicity of Nano curcumin was evaluated by MTT assay and the apoptotic effect (cell cycle arrest and morphology change) was shown by PI staining and microscopy. Results: The MIC of nanocurcumin and curcumin for all four H. pylori strains were 8 µg/ml and 16 µg/ml respectively. The inhibition rate of gastric cancer cells after treatment with curcumin was increased from 6% to 67% for 24h, from 8% to 75% for 48h, from 10% to 83% for 72h. In case of nanocurcumin, the inhibition rate increased from 7% to 69% for 24h, 11% to 87% for 48h and 16% to 97% for 72h. The IC50 of curcumin and Nano-curcumin were 24.20 µM and 18.78 µM respectively for 72 h. The population of cells in sub-G0 population increased from 4.1% in the control group to 24.5% and 57.8% when treated with curcumin and nanocurcumin respectively. After 72h of treatment with nanocurcumin, the apoptotic cells population increased as compared to native curcumin treated cells. Conclusion: The Nano curcumin might be used as a potential therapeutics against gastric cancer and H. Pylori. There is need of further in vivo study in order to validate CUR-NPs activity.  相似文献   
5.
Objective: The objective of this study was to determine the efficacy of curcumin in combination with  intralesional dexamethasone with hyaluronidase in the treatment of oral submucous fibrosis (OSF). Methods: This randomized, double blind, parallel design, clinical trial was conducted at B.P. Koirala Institute of Health Sciences, Nepal. Thirty-four patients with clinically diagnosed OSF were randomized into two groups (17 participants in each) with baseline treatment of intralesional dexamethasone with hyaluronidase for 6 weeks for the both. Curcumin (2gm/day) was provided to Group A (Test) and Group B (Control) received placebo. Interincisal mouth opening, tongue protrusion, cheek flexibility and visual analogue scale (VAS) scoring of burning sensation of oral mucosa was recorded at baseline, 6, 8 and 12 weeks follow-up and independent t-test was used to compare the improvements in two groups. Results: On comparing the 6 weeks and baseline values, in Group A and B the mean difference in mouth opening was 8.82±1.33 mm and 5.53±1.17 mm respectively (p<0.001), in cheek flexibility was 2.94±1.02 mm and 1.94±1.24 mm respectively (p=0.02) and in tongue protrusion was 6.23±1.48 and 3.65±1.37 mm respectively (p<0.001). The findings were consistent in the 8 weeks follow-up. In 12 weeks follow-up, on comparing with the baseline values, in Group A and B, the mean difference in mouth opening was 8.71±1.16 mm and 5.35±1.22 mm respectively (<0.001), ), in cheek flexibility was 2.81±1.01 mm and 1.76±1.35 mm respectively (p=0.02) and in tongue protrusion was 6.06±1.48 and 3.35±1.50 mm respectively (p<0.001). Both the arms showed 100% improvement in burning sensation in 6, 8 and 12 weeks follow-up. Conclusion: Curcumin in combination with intralesional dexamethasone with hyaluronidase is efficacious in the treatment of OSF.  相似文献   
6.
There is a critical need to develop animal models to alleviate vaccine and drug development difficulties against zoonotic viral infections. The coronavirus family, which includes severe acute respiratory syndrome coronavirus 1 and severe acute respiratory syndrome coronavirus 2, crossed the species barrier and infected humans, causing a global outbreak in the 21st century. Because humans do not have pre-existing immunity against these viral infections and with ethics governing clinical trials, animal models are therefore being used in clinical studies to facilitate drug discovery and testing efficacy of vaccines. The ideal animal models should reflect the viral replication, clinical signs, and pathological responses observed in humans. Different animal species should be tested to establish an appropriate animal model to study the disease pathology, transmission and evaluation of novel vaccine and drug candidates to treat coronavirus disease 2019. In this context, the present review summarizes the recent progress in developing animal models for these two pathogenic viruses and highlights the utility of these models in studying SARS-associated coronavirus diseases.  相似文献   
7.
8.
Journal of Interventional Cardiac Electrophysiology - Late-onset atrial fibrillation (LOAF) after valve surgery for degenerative mitral valve disease often with underlying mitral valve prolapse is...  相似文献   
9.
PurposeCartridge based nucleic acid amplification test (CBNAAT) has been endorsed by the WHO as the screening test for diagnosing extrapulmonary tuberculosis (EPTB). In the present study we report the agreement between CBNAAT (Xpert MTB/RIF), liquid culture (LC) and line probe assay (LPA) for diagnosis of Mycobacterium tuberculosis and detection of drug resistance among EPTB cases.MethodsThe EP samples were subjected to CBNAAT (Xpert MTB/RIF, Cepheid, USA) and wherever possible, to LC (MGIT 960, Becton Dickinson, USA) followed sequentially by first line and second line-LPA (FL-LPA, SL-LPA, Hain Lifescience, Germany) on the isolates.ResultsTotal 566/4080 (13.9%) EP samples were detected positive for M. tuberculosis on CBNAAT. Aspirates from lymph nodes were most often positive (11/30; 36.6%), followed by pus (240/873; 27.5%) and CSF samples (166/104; 15.8%). The detection of M. tuberculosis was more in adults than children except in tissue biopsy samples. Rifampicin resistance was also higher among adults except CSF in which resistance was more in children. Total 185 of 566 (32.7%) CBNAAT positive and 770 of 3510 (21.9%) CBNAAT negative samples could be cultured of which 110/185 (59.4%) and 33/770 (4.3%) respectively turned positive. FL-LPA and SL-LPA of 143 culture isolates showed that 27 isolates had drug resistance, of which 3 (2.1%) were XDR, 11 (7.7%) were Pre-XDR (FQ) and 13 (9.1%) were MDR. Of these 27 resistant isolates, 12 were negative by CBNAAT and two were mislabeled as Rifampicin sensitive or indeterminate based on the unique RpoB gene mutation patterns on LPA. The positive and negative agreements between LC and CBNAAT for detection of M. tuberculosis were 67.1% and 92.7% respectively and between LPA and CBNAAT for rifampicin resistance detection were 98.9% and 92.9% respectively.ConclusionsFor EPTB, CBNAAT should be accompanied with LC wherever possible irrespective of the CBNAAT result.  相似文献   
10.
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