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   32711篇
  免费   1611篇
  国内免费   141篇
耳鼻咽喉   321篇
儿科学   724篇
妇产科学   397篇
基础医学   4130篇
口腔科学   932篇
临床医学   2132篇
内科学   8780篇
皮肤病学   536篇
神经病学   2290篇
特种医学   1155篇
外科学   5934篇
综合类   145篇
一般理论   3篇
预防医学   935篇
眼科学   430篇
药学   2337篇
中国医学   102篇
肿瘤学   3180篇
  2023年   158篇
  2022年   253篇
  2021年   575篇
  2020年   303篇
  2019年   431篇
  2018年   526篇
  2017年   457篇
  2016年   514篇
  2015年   521篇
  2014年   703篇
  2013年   891篇
  2012年   1371篇
  2011年   1437篇
  2010年   882篇
  2009年   737篇
  2008年   1433篇
  2007年   1536篇
  2006年   1545篇
  2005年   1651篇
  2004年   1568篇
  2003年   1535篇
  2002年   1453篇
  2001年   1209篇
  2000年   1295篇
  1999年   1124篇
  1998年   453篇
  1997年   321篇
  1996年   340篇
  1995年   289篇
  1994年   267篇
  1993年   271篇
  1992年   790篇
  1991年   722篇
  1990年   680篇
  1989年   731篇
  1988年   650篇
  1987年   600篇
  1986年   544篇
  1985年   525篇
  1984年   338篇
  1983年   287篇
  1979年   263篇
  1978年   186篇
  1977年   161篇
  1974年   157篇
  1973年   166篇
  1972年   166篇
  1971年   156篇
  1970年   155篇
  1969年   144篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
991.
992.
993.
Oxygen-containing functional groups tend to induce a strong interaction between solid adsorbents and iodine molecules, yet have not been systematically investigated. Herein, on the basis of a series of nitric acid-treated graphene oxide (GO) with different contents of oxygen functional groups for iodine adsorption, it was found that the iodine uptake capacity is proportionate to the oxygen content and the diversities of oxygen-containing groups. The density functional theory (DFT) calculation results also suggest that oxygen-containing groups result in strong interactions between iodine molecules and the adsorbents through a covalent bond-forming process, among which -OH groups possess a higher adsorption energy averagely. Such theoretical and experimental work deepens our understanding of the effects of oxygen functional groups on iodine adsorption and provides novel ideas for future design and synthesis of high-performance solid adsorbents for radioactive iodine.  相似文献   
994.
Melt-electrospinning is an eco-friendly method for producing ultra-fine fibers without using any solvent. We prepared webs of poly(ethylene terephthalate) (PET) through melt-electrospinning using CO2 laser irradiation for heating. The PET webs comprised ultra-fine fibers of uniform diameter (average fiber diameter = 1.66 μm, coefficient of variation = 19%). The co-existence of fibers with high and low molecular orientation was confirmed through birefringence measurements. Although the level of high orientation corresponded to that of commercial highly oriented yarn, crystalline diffraction was not observed in the wide-angle X-ray diffraction (WAXD) analysis of the webs. The crystallinity of the webs was estimated using differential scanning calorimetry (DSC). The fibers with higher birefringence did not exhibit any cold crystallization peak. After annealing the web at 116 °C for 5 min, a further increase in the birefringence of the fibers with higher orientation was observed. The WAXD results revealed that the annealed webs showed crystalline diffraction peaks with the orientation of the c-axis along the fiber axis. In summary, the formation of fibers with a unique non-crystalline structure with extremely high orientation was confirmed.  相似文献   
995.
Type A insulin resistance (IR) syndrome is a severe IR form caused by insulin receptor (INSR) gene defects. Antidiabetic drugs, including high‐dose insulin and insulin‐sensitizing agents, often fail to control associated hyperglycemia. Therapy with recombinant human insulin‐like growth factor 1 can be more effective, but it is expensive. We report a case of type A IR syndrome with an in‐frame INSR heterozygous deletion (ΔLeu999) that was treated with a combination of conventional therapy and ipragliflozin, a sodium–glucose cotransporter 2 inhibitor. Treatment reduced hemoglobin A1c levels (10.0–7.5%) and induced weight loss (54.4–52.0 kg) within 2 months, and the effects were sustained for >3 years. Sodium–glucose cotransporter 2 inhibitors might be useful to normalize blood glucose in type A IR syndrome by reducing bodyweight and ameliorating glucotoxicity.  相似文献   
996.
A 38‐year‐old woman with type 1 diabetes, whose fasting plasma glucose levels were >500 mg/dL under 176 U/day of subcutaneous insulin injection, was admitted to Nippon Medical School Hospital, Tokyo, Japan. When insulin was administered intravenously, she was able to maintain favorable glycemic control even under 24 U/day of regular insulin, showing that she was accompanied by subcutaneous insulin resistance. To choose an optimal insulin regimen, we carried out subcutaneous insulin challenge tests without or with heparin mixture, and found a cocktail of insulin lispro and heparin could reduce blood glucose levels markedly. As a consequence, she achieved favorable blood glucose control by continuous subcutaneous insulin infusion of the cocktail. In summary, the insulin and heparin challenge tests are useful for choosing an optimal insulin regimen in cases of subcutaneous insulin resistance.  相似文献   
997.
To date, almost all case reports of insulin‐derived amyloidosis described the presence of a subcutaneous mass that was observable on physical examination. This report presents two cases of insulin‐derived amyloidosis without palpable masses at insulin injection sites. In both cases, blood glucose concentrations improved, and the insulin dose could be reduced by an average of 45% after changing the insulin injection sites. The insulin absorption at the site was reduced to at most 40% of that at a normal site in one case. Magnetic resonance imaging and ultrasonography were useful to screen and differentiate insulin‐derived amyloidosis without a palpable mass. This report showed that insulin‐derived amyloidosis without a palpable mass can be present at the insulin injection site, and has similar clinical effects to insulin‐derived amyloidosis with palpable masses.  相似文献   
998.
Emotional memory consolidation has been associated with rapid eye movement (REM) sleep, and recent evidence suggests that increased electroencephalogram spectral power in the theta (4–8 Hz) frequency range indexes this activity. REM sleep has been implicated in posttraumatic stress disorder (PTSD) as well as in emotional adaption. In this cross-sectional study, thirty young healthy African American adults with trauma exposure were assessed for PTSD status using the Clinician Administered PTSD Scale. Two consecutive night polysomnographic (PSG) recordings were performed and data scored for sleep stages. Quantitative electroencephalographic spectral analysis was used to measure theta frequency components sampled from REM sleep periods of the second-night PSG recordings. Our objective was to compare relative theta power between trauma-exposed participants who were either resilient or had developed PTSD. Results indicated higher right prefrontal theta power during the first and last REM periods in resilient participants compared with participants with PTSD. Right hemisphere prefrontal theta power during REM sleep may serve as a biomarker of the capacity for adaptive emotional memory processing among trauma-exposed individuals.  相似文献   
999.
The interleukin-1 receptor antagonist (IL-1Ra) binds to IL-1 receptors and inhibits IL-1 activity. However, it is not clear whether IL-1Ra plays a protective role in periodontal disease. This study was undertaken to compare experimental periodontitis induced by Aggregatibacter actinomycetemcomitans in IL-1Ra knockout (KO) mice and wild-type (WT) mice. Computed tomography (CT) analysis and hematoxylin-and-eosin (H&E) and tartrate-resistant acid phosphatase (TRAP) staining were performed. In addition, osteoblasts were isolated; the mRNA expression of relevant genes was assessed by real-time quantitative PCR (qPCR); and calcification was detected by Alizarin Red staining. Infected IL-1Ra KO mice exhibited elevated (P, <0.05) levels of antibody against A. actinomycetemcomitans, bone loss in furcation areas, and alveolar fenestrations. Moreover, protein for tumor necrosis factor alpha (TNF-α) and IL-6, mRNA for macrophage colony-stimulating factor (M-CSF), and receptor activator of NF-κB ligand (RANKL) in IL-1Ra KO mouse osteoblasts stimulated with A. actinomycetemcomitans were increased (P, <0.05) compared to in WT mice. Alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OCN)/bone gla protein (BGP), and runt-related gene 2 (Runx2) mRNA levels were decreased (P, <0.05). IL-1α mRNA expression was increased, and calcification was not observed, in IL-1 Ra KO mouse osteoblasts. In brief, IL-1Ra deficiency promoted the expression of inflammatory cytokines beyond IL-1 and altered the expression of genes involved in bone resorption in A. actinomycetemcomitans-infected osteoblasts. Alterations consistent with rapid bone loss in infected IL-Ra KO mice were also observed for genes expressed in bone formation and calcification. In short, these data suggest that IL-1Ra may serve as a potential therapeutic drug for periodontal disease.  相似文献   
1000.
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