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   916篇
  免费   33篇
  国内免费   4篇
耳鼻咽喉   7篇
儿科学   37篇
妇产科学   81篇
基础医学   143篇
口腔科学   3篇
临床医学   54篇
内科学   186篇
皮肤病学   9篇
神经病学   57篇
特种医学   26篇
外科学   53篇
综合类   12篇
预防医学   86篇
眼科学   7篇
药学   115篇
肿瘤学   77篇
  2023年   5篇
  2022年   24篇
  2021年   46篇
  2020年   15篇
  2019年   16篇
  2018年   18篇
  2017年   29篇
  2016年   30篇
  2015年   27篇
  2014年   35篇
  2013年   58篇
  2012年   68篇
  2011年   62篇
  2010年   31篇
  2009年   29篇
  2008年   68篇
  2007年   83篇
  2006年   49篇
  2005年   66篇
  2004年   54篇
  2003年   50篇
  2002年   41篇
  2001年   5篇
  2000年   3篇
  1999年   3篇
  1998年   4篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1993年   4篇
  1992年   1篇
  1991年   4篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   3篇
  1979年   1篇
  1977年   1篇
  1973年   4篇
  1971年   1篇
  1968年   1篇
  1931年   1篇
排序方式: 共有953条查询结果,搜索用时 0 毫秒
1.
2.
Summary: Exposure to irradiated Plasmodium sporozoites (g‐spz) results in protection against malaria. Like infectious spz, g‐spz colonize hepatocytes to undergo maturation. Disruption of liver stage development prevents the generation of protection, which appears, therefore, to depend on liver stage antigens. Although some mechanisms of protection have been identified, they do not include a role for intrahepatic mononuclear cells (IHMC). We demonstrated that P. berghei g‐spz‐immune murine IHMC adoptively transfer protection to naive recipients. Characterization of intrahepatic CD4+ T cells revealed an immediate, albeit transient, response to g‐spz, while the response of CD8+ T cells is delayed until acquisition of protection. It is presumed that activated CD8+ T cells home to the liver to die; g‐spz‐induced CD8+CD45RBloCD44hi T cells, however, persist in the liver, but not the spleen, during protracted protection. The association between CD8+CD45RBloCD44hi T cells and protection has been verified using MHC class I and CD1 knockout mice and mice with disrupted liver stage parasites. Based on kinetic studies, we propose that interferon‐g, presumably released by intrahepatic effector CD8+ T cells, mediates protection; the persistence of CD8+ T cells is, in turn, linked to Plasmodium antigen depots and cytokines released by CD4+ T cells and/or NK T cells.  相似文献   
3.
In order to evaluate the relationship between serum concentrations of interleukin-10 (IL-10), IL-6, and acute phase proteins in rheumatoid arthritis (RA) patients treated with methotrexate (MTX) or intramuscular gold (IMG) we determined IL-10, IL-6, C-reactive protein (CRP), alpha-1-acid glycoprotein (AGP) and alpha-1-antichymotrypsin (ACT) in the sera of 35 RA patients. IL-10 and IL-6 levels were evaluated using an enzyme-linked immunoassay (ELISA). AGP and ACT level were measured using rocket immunoelectrophoresis. IL-10 serum level was not increased in RA patients as compared to controls (58.7 ± 18.1 pg/ml vs. 57.2 ± 11.9 pg/ml). IL-6 level was significantly elevated (91.6 ± 46.9 pg/ml vs. 45 ± 19 pg/ml, p < 0.05). CRP was significantly increased as compared to healthy controls (35 ± 19 mg/l vs. 3 ± 2 mg/l, p < 0.05). Patients treated with MTX or IMG presented an increased level of IL-10 and decreased amounts of IL-6, as compared to those treated with NSAID only. However, only changes between patients treated with IMG and NSAID were found to be statistically significant. A good negative correlation between IL-10 and IL-6 serum level was found (r = –0.75, p < 0.05). A positive significant correlation between IL-6 serum level and CRP (r = 0.62, p < 0.05), AGP (r = 0.78, p < 0.05) and ACT (r = 0.45, p < 0.05) was established. On the other hand, a negative correlation between IL-10 and serum level of CRP (r = –0.76, p < 0.05), AGP (r = –0.64, p < 0.05) and ACT (r = –0.38, p < 0.05) was also observed. Moreover, these relationships were maintained when patients treated with MTX, IMG, or NSAID were analyzed independently. According to the data thus far obtained, it seems that IL-10 decreases IL-6 production, and thereby indirectly affects the acute phase response, decreasing CRP, AGP, and ACT concentration in RA patients.Abbreviations ACT -1-antichymotrypsin - AGP 1-acid glycoprotein - APP acute phase protein - CRP C-reactive protein - CSF colony stimulating factor - IFN interferon - IL interleukin - IMG intramuscular gold - MTX methotrexate - NSAID non-steroidal anti-inflammatory drug - RA rheumatoid arthritis  相似文献   
4.
A previous case report described the formation of a complex between a monoclonal IgA with cryolabile properties and C-reactive protein (CRP). Our study provides the first evidence for the frequent occurrence of CRP in cryoglobulins (Cg) of all three types according to Brouet's classification. We performed a systematic immunochemical analysis of cryoglobulins from 18 patients by Western blotting and in 15 of 18 cryoprecipitates a single band (23 KD), immunoreactive with anti-CRP antibody, was demonstrable irrespective of the clonal composition of the cryoglobulins. This band was detectable in 4/5 of type I, in 6/8 of type II, and in 5/5 of type III cryoprecipitates, classified according to Brouet et al. In addition, the complement proteins C1q and C3 were present in nearly all CRP-containing cryoglobulins, presumably reflecting previous activation of the classical complement pathway at least. All three CRP-negative cryoprecipitates were derived from sera with low cryoglobulin content (1-2 g/l). Longitudinal investigation of 23 cryoprecipitates from seven patients confirmed that successful detection of CRP by Western blotting depends on the protein concentration of the cryoglobulins. Since complexed CRP was previously shown to be an effective activator of complement, via C1q binding, CRP may modulate pathophysiologic effects mediated by cryoglobulins in vivo.  相似文献   
5.
We study an optical device designed for converting the polarized Gaussian beam into an optical vortex of tunable polarization. The proposed device comprised a set of three specially prepared nematic liquid crystal cells and a nano-spherical phase plate fabricated from two types of glass nanotubes. This device generates a high-quality optical vortex possessing one of the multiple polarization states from the uniformly polarized input Gaussian beam. Its small size, simplicity of operation, and electrical steering can be easily integrated into the laboratory and industrial systems, making it a promising alternative to passive vortex retarders and spatial light modulators.  相似文献   
6.
The relationship of high-carbohydrate (HC) meal intake to metabolic syndrome is still not fully explained. Metabolomics has the potential to indicate metabolic pathways altered by HC meals, which may improve our knowledge regarding the mechanisms by which HC meals may contribute to metabolic syndrome development. The fasting and postprandial metabolic response to HC or normo-carbohydrate (NC) meals with/without cinnamon + capsicum intake was evaluated using untargeted metabolomics and compared between normal-weight (NW) and overweight/obese (OW/OB) healthy men. Healthy male participants (age-matched) were divided into two groups (12 subjects per group). One was composed of men with normal weight (NW) and the other of men with overweight/obesity (OW/OB). On separate visits (with 2–3 week intervals), the participants received standardized HC or NC meals (89% or 45% carbohydrates, respectively). Fasting (0 min) and postprandial (30, 60, 120, 180 min) blood were collected for untargeted plasma metabolomics. Based on each metabolic feature’s intensity change in time, the area under the curve (AUC) was calculated. Obtained AUCs were analyzed using multivariate statistics. Several metabolic pathways were found dysregulated after an HC meal in people from the OW/OB group but not the NW group. The consumption of HC meals by people with overweight/obesity led to a substantial increase in AUC, mainly for metabolites belonging to phospholipids and fatty acid amides. The opposite was observed for selected sphingolipids. The intake of cinnamon and capsicum normalized the concentration of selected altered metabolites induced by the intake of HC meals. A HC meal may induce an unfavourable postprandial metabolic response in individuals with overweight/obesity, and such persons should avoid HC meals.  相似文献   
7.
8.
BackgroundSteroid hormones play an important role in heart failure (HF) pathogenesis, and clinical data have revealed disordered steroidogenesis in male patients with HF. However, there is still a lack of studies on steroid hormones and their receptors during HF progression. Therefore, a porcine model of tachycardia-induced cardiomyopathy corresponding to HF was used to assess steroid hormone concentrations in serum and their nuclear receptor levels in heart tissue during the consecutive stages of HF.Methods and ResultsMale pigs underwent right ventricular pacing and developed a clinical picture of mild, moderate, or severe HF. Serum concentrations of dehydroepiandrosterone, testosterone, dihydrotestosterone, estradiol, aldosterone, and cortisol were assessed by enzyme-linked immunosorbent assay. Androgen receptor, estrogen receptor alpha, mineralocorticoid receptor, and glucocorticoid receptor messenger RNA levels in the left ventricle were determined by qPCR.The androgen level decreased in moderate and severe HF animals, while the corticosteroid level increased. The estradiol concentration remained stable. The quantitative real-time polymerase chain reaction revealed the downregulation of androgen receptor in consecutive stages of HF and increased expression of mineralocorticoid receptor messenger RNA under these conditions.ConclusionsIn the HF pig model, deteriorated catabolic/anabolic balance, manifested by upregulation of aldosterone and cortisol and downregulation of androgen signaling on the ligand level, was augmented by changes in steroid hormone receptor expression in the heart tissue.  相似文献   
9.
10.
Plastic bronchitis (PB), although a rare cause of airway obstruction, has mortality rates up to 50% in children after Fontan-type cardiac surgery. We present the case of an 18-month-old female patient with PB following pneumonia. At 6 months of age, the patient underwent the Glenn procedure due to functionally univentricular heart. Fiberoptic bronchoscopy revealed complete blockage of the left bronchus by mucoid casts. Pharmacotherapy consisted of glucocorticosteroids, azithromycin, and enalapril maleate. The child also received nebulized 3% NaCl solution, which proved to be beneficial. In children submitted to Fontan-type procedures, physicians must be alert for PB, which can be triggered by respiratory tract infection.  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