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   4069篇
  免费   248篇
  国内免费   87篇
耳鼻咽喉   78篇
儿科学   58篇
妇产科学   160篇
基础医学   650篇
口腔科学   85篇
临床医学   365篇
内科学   671篇
皮肤病学   114篇
神经病学   235篇
特种医学   128篇
外科学   656篇
综合类   175篇
预防医学   191篇
眼科学   65篇
药学   419篇
  2篇
中国医学   80篇
肿瘤学   272篇
  2024年   17篇
  2023年   70篇
  2022年   131篇
  2021年   193篇
  2020年   109篇
  2019年   104篇
  2018年   120篇
  2017年   103篇
  2016年   106篇
  2015年   159篇
  2014年   186篇
  2013年   175篇
  2012年   278篇
  2011年   284篇
  2010年   160篇
  2009年   120篇
  2008年   199篇
  2007年   201篇
  2006年   204篇
  2005年   170篇
  2004年   143篇
  2003年   121篇
  2002年   116篇
  2001年   104篇
  2000年   100篇
  1999年   94篇
  1998年   28篇
  1997年   25篇
  1996年   28篇
  1995年   21篇
  1994年   19篇
  1992年   34篇
  1991年   40篇
  1990年   40篇
  1989年   34篇
  1988年   19篇
  1987年   22篇
  1986年   22篇
  1985年   30篇
  1984年   19篇
  1983年   13篇
  1979年   16篇
  1978年   21篇
  1977年   13篇
  1976年   13篇
  1975年   15篇
  1974年   17篇
  1973年   14篇
  1972年   18篇
  1966年   16篇
排序方式: 共有4404条查询结果,搜索用时 18 毫秒
41.
成骨细胞是一类特殊的具有成骨潜能的细胞,在骨重建及骨稳态维持中发挥重要的作用,其分化过程受到众多因素的调控.非编码RNA(non-coding RNAs,ncRNAs),尤其是微小RNA(microRNAs)和长链非编码RNA(long non-coding RNAs,lncRNAs)在成骨细胞增殖、分化、矿化和凋亡等...  相似文献   
42.
CGS 15435A, a novel thromboxane (Tx) synthetase inhibitor (5-chloro-1-methyl-2-(3-pyridyl)-3-indolhexanoic acid HCl), had a selectivity for Tx synthetase 100,000-fold greater than that for cyclooxygenase, PGI2 synthetase and lipoxygenase enzymes. In conscious beagles, 1 h following a single 3 mg/kg p.o. dose, serum TxB2 was inhibited 95% by CGS 15435 and 82% by dazoxiben (DAZ). Unlike the short acting Tx synthetase inhibitor DAZ, CGS 15435A significantly inhibited TxB2 formation 4, 6, 12 and 24 h after dosing. Serum levels of 6-keto PGF1 alpha and PGE2 were significantly increased following the administration of either drug. CGS 15435A and DAZ were further examined in a model with known Tx involvement. Thrombotic sudden death, produced in anesthetized rabbits by injection of 0.75 mg/kg arachidonic acid (AA) i.v. resulted in a 45% fall in the platelet count and 0% survival. Pretreatment with DAZ (8.6 mumol/kg i.v.) at 0.25 or 2 h pre-AA resulted in 3 and 42% thrombocytopenia and 100 and 0% survival respectively. CGS 15435A (8.6 mumol/kg i.v.) prevented the increases in plasma TxB2 levels, thrombocytopenia and sudden death with pretreatment at 0.25 h (0% thrombocytopenia and 100% survival) or 24 h (11% thrombocytopenia and 83% survival) before AA. These data indicate that CGS 15435A is a potent and selective Tx synthetase inhibitor with a long duration of action, and suggest that the compound could be useful in chronic, non-symptomatic indications of Tx involvement.  相似文献   
43.
1-取代吡唑烷酮类抗惊构效关系的研究   总被引:5,自引:0,他引:5  
1-正癸基吡唑烷-3-酮(Ⅱ结构式见表1)是欧洲专利报道的一种新型减肥剂。White等报道该化合物可通过血脑屏障,并对γ-氨基丁酸氨基转移酶(GABA-T)有强烈的抑制活性,但对谷氨酸脱羧酶的抑制作用较弱,因此可引起脑内γ-氨基丁酸(GABA)水平的升高,故我们相信应有抗惊活性。经我们合成后,发现Ⅱ确有良好的抗癲痫活性,抗小鼠最大电  相似文献   
44.
目的 观察使用薇诺娜舒敏保湿特护霜对疫情期间医护人员佩戴医用口罩后皮肤屏障修复作用及皮肤敏感改善情况.方法 采用自身前后对照研究,选取受试者佩戴口罩后的右侧面颊为受试区.入组当天晨起及佩戴口罩4h后检测经表皮水分流失(transepidermal waterloss,TEWL)及角质层含水量,随后发放受试品(薇诺娜舒敏...  相似文献   
45.
Pseudorabies virus (PRV), the causative agent of Aujeszky’s disease, is one of the most important infectious pathogens threatening the global pig industry. Like other members of alphaherpesviruses, PRV establishes a lifelong latent infection and occasionally reactivates from latency after stress stimulus in infected pigs. Latent infected pigs can then serve as the source of recurrent infection, which is one of the difficulties for PRV eradication. Virus latency refers to the retention of viral complete genomes without production of infectious progeny virus; however, following stress stimulus, the virus can be reactivated into lytic infection, which is known as the latency-reactivation cycle. Recently, several research have indicated that alphaherpesvirus latency and reactivation is regulated by a complex interplay between virus, neurons, and the immune system. However, with those limited reports, the relevant advances in PRV latency are lagging behind. Therefore, in this review we focus on the regulatory mechanisms in PRV latency via summarizing the progress of PRV itself and that of other alphaherpesviruses, which will improve our understanding in the underlying mechanism of PRV latency and help design novel therapeutic strategies to control PRV latency.  相似文献   
46.
High mobility group box 1 (HMGB1) mediates proinflammatory responses in inflammatory diseases. Lycopene found in tomatoes and tomato products has anti-oxidant, anti-cancer and antiinflammatory effects. The potential anti-inflammatory roles of lycopene in HMGB1-mediated proinflammatory responses in both primary human umbilical vein endothelial cells (HUVECs) and animal were investigated. The anti-inflammatory effects of lycopene were determined including permeability, monocyte adhesion and migration, and activation of proinflammatory proteins and HMGB1 receptors on HMGB1 activated HUVECs. In the in vivo model, the anti-inflammatory effect of lycopene was assessed by monitoring vascular permeability and migration of leukocytes to the peritoneal cavity of mice injected with lycopene. Lycopene inhibited lipopolysaccharide (LPS)-mediated release of HMGB1, expression of HMGB1-mediated tumor necrosis factor (TNF)-secretory phospholipase A2 (sPLA2)-IIA, and HMGB1-mediated pro-inflammatory signaling responses in endothelial cells. It did this through down-regulation of cell surface expression of cell adhesion molecules (CAMs), HMGB1 receptors, toll-like receptor (TLR)-2, and -4, and receptors for advanced glycation end products (RAGE). These findings suggest that lycopene promotes barrier integrity, inhibits monocyte adhesion and migration to HMGB1 activating HUVECs by blocking activation of proinflammatory cytokines and expression of CAMs and HMGB1 receptors, thereby showing its usefulness as a therapy for vascular inflammatory diseases.  相似文献   
47.
Le?niowski-Crohn disease is an inflammatory process, involving all layers of the intestine, mesentery and regional lymph nodes. During the development of the disease, a thickening of the intestine wall, stricture of its lumen and adhesions have been observed. The aim of the study was to present the case of a 27-year-old pregnant woman with Crohn's disease, a very rare complication of gestation.  相似文献   
48.
49.
Objective To present a unique case of a 63 year-old woman with coexistent adenocarcinoma of the ovary, endometrium, cervix and fallopian tube. Materials and methods A case report from a tertiary health center. Results A woman presenting with postmenopausal bleeding and abdominal distantion was assessed by endometrial biopsy and explorative surgery. The frozen section of the mass on the right adnex revealed malign mucinous carcinoma of the ovary. As usual, optimal debulking was performed as initial surgical staging procedure of ovarian cancer. The microscopic examination of the right ovary revealed a typical mucinous cystadenocarcinoma. Furthermore, the focal endometrial irregularity at the left uterine cornus turned out to be a well differentiated endometrial carcinoma of the endometrioid type with <1/3 myometrial invasion. The pale infiltrative lesion in the cervix also turned out to be an adenocarcinoma of the endocervical type with deep stromal invasion and areas of diffuse glandular dysplasia and in-situ glandular neoplasia at the periphery. Besides, several sections from the left fallopian tube uncovered diffuse dysplasia in the lining epithelium and a focus of adenocarcinoma with papillary and cribriform pattern. Discussion When compared with patients having metastatic lesions, most synchronous female malignancies are accompanied with early stage and low-grade with a more favorable prognosis. However, there is paucity of data for the exact criterion to distinguish primary tumors from metastatic lesions. In such cases, the validity of immunohistochemical and cloning studies are not clear.  相似文献   
50.
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