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   3381篇
  免费   206篇
  国内免费   21篇
耳鼻咽喉   49篇
儿科学   124篇
妇产科学   46篇
基础医学   511篇
口腔科学   93篇
临床医学   262篇
内科学   786篇
皮肤病学   175篇
神经病学   215篇
特种医学   80篇
外科学   245篇
综合类   33篇
预防医学   193篇
眼科学   87篇
药学   286篇
中国医学   17篇
肿瘤学   406篇
  2024年   4篇
  2023年   42篇
  2022年   67篇
  2021年   111篇
  2020年   56篇
  2019年   83篇
  2018年   118篇
  2017年   89篇
  2016年   87篇
  2015年   90篇
  2014年   135篇
  2013年   139篇
  2012年   266篇
  2011年   247篇
  2010年   188篇
  2009年   129篇
  2008年   197篇
  2007年   228篇
  2006年   254篇
  2005年   205篇
  2004年   193篇
  2003年   185篇
  2002年   177篇
  2001年   26篇
  2000年   26篇
  1999年   25篇
  1998年   30篇
  1997年   29篇
  1996年   22篇
  1995年   26篇
  1994年   15篇
  1993年   13篇
  1992年   11篇
  1991年   7篇
  1990年   12篇
  1989年   15篇
  1988年   5篇
  1987年   10篇
  1986年   7篇
  1985年   8篇
  1984年   3篇
  1983年   4篇
  1982年   9篇
  1981年   2篇
  1980年   4篇
  1979年   2篇
  1976年   1篇
  1974年   2篇
  1969年   1篇
  1968年   1篇
排序方式: 共有3608条查询结果,搜索用时 31 毫秒
41.
We previously designed and synthesized the new nuclear factor kappaB (NF-kappaB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) derived from the structure of the antibiotic epoxyquinomicin C. We looked into the effect of DHMEQ on cellular phenotypes and tumor growth in mice injected with human breast carcinoma cell line MDA-MB-231 or MCF-7. In estrogen-independent breast adenocarcinoma cell line MDA-MB-231, NF-kappaB is constitutively activated. The addition of DHMEQ (10 microg/mL) completely inhibited the activated NF-kappaB for at least 8 hours. On the other hand, NF-kappaB is not activated in estrogen-dependent MCF-7 cells. In this cell line, DHMEQ completely inhibited the tumor necrosis factor-alpha-induced activation of NF-kappaB. DHMEQ did not inhibit the degradation of IkappaB but inhibited the nuclear translocation of NF-kappaB by both p65/p50 and RelB/p52 pathways. MDA-MB-231 cells secrete interleukin (IL)-6 and IL-8 without stimulation, and DHMEQ decreased the secretion levels of both cytokines. When MDA-MB-231 or MCF-7 cells were stimulated by tumor necrosis factor-alpha, the inhibitory effects of DHMEQ were still maintained. I.p. administration of DHMEQ (thrice a week) significantly inhibited the tumor growth of MDA-MB-231 (12 mg/kg) or MCF-7 (4 mg/kg) in severe combined immunodeficiency mice. No toxicity was observed during the experiment, including the loss of body weight. An immunohistological study on resected MCF-7 tumors showed that DHMEQ inhibited angiogenesis and promoted apoptosis. Furthermore, in Adriamycin-resistant MCF-7 cells highly expressing multidrug resistance gene-1, DHMEQ also exhibited the above capability, including down-regulation of IL-8. Thus, DHMEQ might be a potent drug for the treatment of various breast carcinomas by inhibiting the NF-kappaB activity.  相似文献   
42.
Obesity-associated severe asthma is a distinct phenotype characterised by resistance to standard asthma therapies. Bariatric surgery appears to be a viable alternative for those who have failed trials of traditional weight loss methods. However, anaesthetic and surgical risks are potential barriers. We describe three patients with treatment-resistant obesity-associated severe asthma who underwent bariatric surgery without complications due to the multidisciplinary perioperative planning and care involved in these complex cases. All three patients showed improvements in asthma control and reduction in maintenance medication use post-surgery.  相似文献   
43.
44.
4‐(4‐Hydroxyphenyl)‐2‐butanol (rhododendrol, RD), a skin‐whitening agent, was reported to cause skin depigmentation in some users, which is attributed to its cytotoxicity to melanocyte. It was reported that cytotoxicity to melanocyte is possibly mediated by oxidative stress in a tyrosinase activity‐dependent manner. We examined the effect of UV radiation (UVR) on RD‐induced melanocyte cytotoxicity as an additional aggravating factor. UVR enhanced RD‐induced cytotoxicity in normal human epidermal melanocytes (NHEMs) via the induction of endoplasmic reticulum (ER) stress. Increased generation of intracellular reactive oxygen species (ROS) was detected. Pretreatment with N‐acetyl cysteine (NAC), antioxidant and precursor of glutathione significantly attenuated ER stress‐induced cytotoxicity in NHEMs treated with RD and UVR. Increase in cysteinyl‐RD‐catechol and RD‐pheomelanin in NHEMs treated with RD and UVR suggested that, after UVR excitation, RD or RD metabolites are potent ROS‐generating substances and that the tendency to produce RD‐pheomelanin during melanogenesis amplifies ROS generation in melanocytes. Our results help to elucidate the development mechanisms of RD‐induced leukoderma and provide information for innovation of safe skin‐whitening compounds.  相似文献   
45.
46.
47.
Association of congenital cytomegalovirus (CMV) infection with autism spectral disorder (ASD) has been suggested since 1980s. Despite the observed association, its role as a risk factor for ASD remains to be defined. In the present review, we systematically evaluated the available evidence associating congenital CMV infection with ASD using PubMed, Web of Science, Cochrane Library, and Embase databases. Any studies on children with CMV infection and ASD were evaluated for eligibility and three observational studies were included in meta-analysis. Although a high prevalence of congenital CMV infection in ASD cases (OR 11.31, 95% CI 3.07–41.66) was indicated, too few events (0–2 events) in all included studies imposed serious limitations. There is urgent need for further studies to clarify this issue.  相似文献   
48.
Nuclear factor (NF)‐κB essential modifier (NEMO), also known as IκB kinase subunit‐γ (IKKγ), is a pivotal molecule in the NF‐κB signaling pathway. Mutations of NEMO cause incontinentia pigmenti and X‐linked ectodermal dysplasia with immunodeficiency. Mendelian susceptibility to mycobacterial diseases (MSMD), which confers an almost selective predisposition to mycobacterial infection, is also caused by NEMO mutations. We herein report the first case of a patient with X‐linked recessive (XR) MSMD who developed cutaneous squamous cell carcinoma, thyroid cancer and Langerhans cell histiocytosis. The relationship between NEMO mutation and oncogenesis is discussed.  相似文献   
49.
50.
IOX4, a hypoxia-inducible factor stabilizer, is classified as a banned substance for horses in both horse racing and equestrian sports. We recently reported the pharmacokinetic profiles of IOX4 in horse plasma and urine and also identified potential monitoring targets for the doping control purpose. In this study, a long-term longitudinal analysis of IOX4 in horse hair after a nasoesophageal administration of IOX4 (500 mg/day for 3 days) to three thoroughbred mares is presented for the first time for controlling the abuse/misuse of IOX4. Six bunches of mane hair were collected at 0 (pre), 1, 2, 3, and 6 month(s) postadministration. Our results showed that the presence of IOX4 was identified in all postadministration horse hair samples, but no metabolite could be detected. The detection window for IOX4 could achieve up to 6-month postadministration (last sampling point) by monitoring IOX4 in hair. In order to evaluate the longitudinal distribution of IOX4 over 6 months, a validated quantification method of IOX4 in hair was developed for the analysis of the postadministration samples. Segmental analysis of 2-cm cut hair across the entire length of postadministration hair showed that IOX4 could be quantified up to the level of 1.84 pg/mg. In addition, it was found that the movement of the incorporated IOX4 band in the hair shaft over 6 months varied among the three horses due to individual variation and a significant diffusion of IOX4 band up to 10 cm width was also observed in the 6-month postadministration hair samples.  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