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   2672篇
  免费   230篇
  国内免费   11篇
耳鼻咽喉   21篇
儿科学   101篇
妇产科学   113篇
基础医学   431篇
口腔科学   87篇
临床医学   308篇
内科学   549篇
皮肤病学   129篇
神经病学   152篇
特种医学   38篇
外科学   186篇
综合类   52篇
一般理论   4篇
预防医学   218篇
眼科学   66篇
药学   222篇
中国医学   51篇
肿瘤学   185篇
  2024年   6篇
  2023年   49篇
  2022年   66篇
  2021年   221篇
  2020年   164篇
  2019年   192篇
  2018年   189篇
  2017年   109篇
  2016年   144篇
  2015年   117篇
  2014年   162篇
  2013年   189篇
  2012年   251篇
  2011年   237篇
  2010年   117篇
  2009年   84篇
  2008年   113篇
  2007年   105篇
  2006年   88篇
  2005年   92篇
  2004年   60篇
  2003年   31篇
  2002年   30篇
  2001年   11篇
  2000年   10篇
  1999年   10篇
  1998年   2篇
  1997年   4篇
  1996年   5篇
  1995年   4篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1989年   2篇
  1988年   6篇
  1987年   9篇
  1986年   4篇
  1985年   5篇
  1984年   3篇
  1980年   1篇
  1979年   4篇
  1977年   1篇
  1976年   1篇
  1973年   2篇
  1936年   1篇
排序方式: 共有2913条查询结果,搜索用时 187 毫秒
1.
2.
Cancer Chemotherapy and Pharmacology - Despite all advances in the treatment of ovarian cancer (OC), it remains the most lethal gynecological malignancy worldwide. There are growing amounts of...  相似文献   
3.
The World Health Organization has reported an annual global suicide rate of 14.5 per 100,000 people. On the other hand, it is estimated that approximately one‐third of the global population are infected with Toxoplasma gondii (T. gondii) parasite. It is widely assumed that microbial pathogens, such as T. gondii, are probably associated with affective and behavioural modulation. The present article aimed to assess the proposed role of toxoplasmosis in raising the risk of suicidal ideation (SI) and suicide attempts (SA) using the available epidemiological data. Seven major electronic databases and the Internet search engine Google were searched for all the studies published between the 1st of January 1950 and 31st of October 2019. The heterogeneity and the risk of bias within and across studies were assessed. Following data extraction, pooled odds ratios (ORs) with 95% confidence interval (CI) across studies were calculated using the random‐effects models. A total number of 9,696 articles were screened and 27 studies were regarded as eligible in our systematic review (SI with five papers and 22 papers on SA). A significant association was detected between antibodies against T. gondii with TA (ORs = 1.57; 95% confidence interval [CI] 1.23–2.00, p = .000). Exploration of the association between T. gondii and SA yielded a positive effect of seropositivity for IgG antibodies but not IgM. Despite the limited number of studies, a statistical association was detected between suicidal behaviours and infection with latent T. gondii.  相似文献   
4.
Aim: Rheumatoid arthritis (RA) is the most common chronic inflammatory erosive joint disease with the worldwide distribution of approximately 0.5–1.0%. Etiology of RA is not exactly known but immunologic and genetic factors play an important role in the pathogenesis of the disease. Genetic factors such as human leukocyte antigens (HLA) are responsible for many autoimmune diseases; therefore we decided to look for a correlation between RA and the presence of HLA‐DQβ1 alleles as possible genetic markers. Methods: Genomic DNA from the whole blood samples of 25 patients with RA and 86 normal individuals as control group were extracted by salting out method. The genomic DNA was amplified by polymerase chain reaction‐sequence specific primer (PCR‐SSP) technique. HLA‐typing was done by this method after optimizing the PCR reaction for each allele. In this procedure seven serological subclasses of HLA‐DQβ1 can be detected. Results: Comparing the results between the patients and controls show a significant increase in the frequency of HLA‐DQ8 (*0302, *0305) alleles in RA patients. The P‐values were 0.007 and the relative risk for these alleles was evaluated higher than 1. Conclusions: The results suggest that DQ8 is the dominant HLA‐DQβ1 allele that is associated with susceptibility to RA in north‐eastern Iran.  相似文献   
5.
Sputum and serum from patients with active pulmonary tuberculosis (TB), healthy purified protein derivative-positive adults, and patients with bacterial pneumonia were collected to simultaneously assess local immunity in the lungs and peripheral blood. To determine whether cytokine profiles in sputum from TB patients and control subjects were a reflection of its cellular composition, cytospin slides were prepared in parallel and assessed for the presence of relative proportions of epithelial cells, neutrophils, macrophages, and T cells. Gamma interferon (IFN-γ) in sputum from TB patients was markedly elevated over levels for both control groups. With anti-TB therapy, IFN-γ levels in sputum from TB patients decreased rapidly and by week 4 of treatment were comparable to those in sputum from controls. Further, IFN-γ levels in sputum closely followed mycobacterial clearance. Although detected at fourfold-lower levels, IFN-γ immunoreactivities in serum followed kinetics in sputum. TNF-α, interleukin 8 (IL-8) and IL-6 also were readily detected in sputum from TB patients at baseline and responded to anti-TB therapy. In contrast to IFN-γ, however, TNF-α and IL-8 levels also were elevated in sputum from pneumonia controls. These data indicate that sputum cytokines correlate with disease activity during active TB of the lung and may serve as potential early markers for sputum conversion and response to anti-TB therapy.  相似文献   
6.
The pathophysiologic basis for the exuberant intracellular growth of Mycobacterium avium complex (MAC) in AIDS patients is unclear but may relate to altered expression of modulatory cytokines. Interleukin (IL)-1, IL-6, and TNF- expression by monocytes from AIDS patients and healthy subjects (HS) stimulated with isogeneic MAC strains (SmT, smooth-transparent, virulent; SmD, smooth-domed, avirulent) was examined. Spontaneous cytokine production was not observed in patients with AIDS. MAC strains induced less IL-1 and IL-1 release in AIDS patients than HS (P < 0.05). The ratio of cell-associated to supernatant IL-1 also was increased in AIDS patients (P = 0.03). IL-1 mRNA expression paralleled protein release in either group of subjects. In both HS and AIDS patients, stimulation with SmD induced more IL-1 and TNF- release by monocytes compared to SmT. In AIDS patients, SmD also induced greater IL-6 release than SmT (P < 0.01). Alterations in monocyte expression and compartmentalization of the regulatory cytokines IL-1 and IL-6 may enhance bacterial replication and contribute to the patho-genesis of MAC infection in AIDS.  相似文献   
7.
Mitochondrial translation is essential for the biogenesis of the mitochondrial oxidative phosphorylation system (OXPHOS) that synthesizes the bulk of ATP for the cell. Hypomorphic and loss-of-function variants in either mitochondrial DNA or in nuclear genes that encode mitochondrial translation factors can result in impaired OXPHOS biogenesis and mitochondrial diseases with variable clinical presentations. Compound heterozygous or homozygous missense and frameshift variants in the FARS2 gene, that encodes the mitochondrial phenylalanyl-tRNA synthetase, are commonly linked to either early-onset epileptic mitochondrial encephalopathy or spastic paraplegia. Here, we expand the genetic spectrum of FARS2-linked disease with three patients carrying novel compound heterozygous variants in the FARS2 gene and presenting with spastic tetraparesis, axial hypotonia and myoclonic epilepsy in two cases.Subject terms: Metabolic disorders, Mutation  相似文献   
8.
Bacille Calmette-Guérin (BCG) osteomyelitis is a very rare complication of BCG vaccination. We report a 14-month-old boy who received BCG vaccination at birth. He developed pain and swelling in his left calf at 11 months of age. BCG osteomyelitis was diagnosed in right femur and left tibia. He had no evidence of immunodeficiency. After antituberculous therapy and surgical treatment, the bone lesions disappeared and he was discharged from hospital without any sequela during 11 months of follow-up.  相似文献   
9.
Monocytes, like all leukocytes, undergo a series of sequential steps during extravasation from blood into tissues: tethering, rolling, adhesion and diapedesis. We have discovered an essential step, which we call locomotion, in which the monocyte moves from a site of firm adhesion to the nearest junction to begin diapedesis. Blocking CD11a-CD18 and CD11b-CD18 on human monocytes or adhesion molecules ICAM-1 and ICAM-2 on endothelial cells prevented the monocytes from reaching junctions. The blocked monocytes spun in circles as if they were unable to direct their movement despite being able to adhere and polarize normally. This step fills a gap in the paradigm of extravasation as a multistep process.  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