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   1414篇
  免费   68篇
  国内免费   14篇
耳鼻咽喉   4篇
儿科学   37篇
妇产科学   9篇
基础医学   143篇
口腔科学   12篇
临床医学   109篇
内科学   468篇
皮肤病学   24篇
神经病学   37篇
特种医学   25篇
外科学   251篇
综合类   23篇
预防医学   198篇
眼科学   16篇
药学   90篇
中国医学   5篇
肿瘤学   45篇
  2024年   2篇
  2023年   11篇
  2022年   39篇
  2021年   67篇
  2020年   31篇
  2019年   42篇
  2018年   58篇
  2017年   41篇
  2016年   40篇
  2015年   42篇
  2014年   44篇
  2013年   67篇
  2012年   95篇
  2011年   94篇
  2010年   78篇
  2009年   66篇
  2008年   66篇
  2007年   107篇
  2006年   76篇
  2005年   66篇
  2004年   74篇
  2003年   64篇
  2002年   36篇
  2001年   26篇
  2000年   13篇
  1999年   15篇
  1998年   9篇
  1997年   3篇
  1996年   7篇
  1994年   3篇
  1992年   7篇
  1991年   5篇
  1990年   16篇
  1989年   11篇
  1988年   10篇
  1987年   10篇
  1986年   16篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1981年   4篇
  1976年   6篇
  1973年   3篇
  1972年   1篇
  1968年   2篇
  1967年   5篇
  1966年   1篇
  1965年   1篇
  1944年   2篇
  1939年   1篇
排序方式: 共有1496条查询结果,搜索用时 15 毫秒
991.
992.

Objective:

To find an association between human leukocyte antigen (HLA) class II DRB1, DRB3, DRB4, and DRB5 alleles frequencies in a sample of Iraqi patients with Guillain-Barré syndrome (GBS) and compare with a healthy control group.

Methods:

We performed a cross-sectional study consisting of 30 Iraqi Arab patients with GBS attending the Neurological Department in the Neuroscience Hospital, Baghdad, Iraq between September 2012 and June 2013. The control group comprised 42 apparently healthy volunteers. Human leukocyte antigen genotyping for HLA DRB1, DRB3, DRB4, and DRB5 was performed using the polymerase chain reaction-sequence-specific primers method. The allele frequencies were compared across both groups. Major histocompatibility complex (MHC)-class II HLA-DR genotyping and serotyping were performed by software analysis.

Results:

We found increased frequencies of HLA genotype DRB1*03:01 (p=0.0009), DRB1*07:01 (p=0.0015), and DRB4*01:01 (p<0.0001) in patients with GBS compared with healthy controls. The HLA DR6 was increased in the control group (p<0.0001).

Conclusions:

Our results suggest an association between HLA-DRB1*03:01, DRB1*07:01, DRB4*01:01, and HLA DR3, DR7 and a susceptibility to GBS.Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy that is autoimmune in nature, and manifests as a rapidly evolving reflexic motor paralysis with or without sensory disturbance and autonomic system involvement.1 Guillain-Barré syndrome is subdivided into the most common type, which is the acute inflammatory demyelinating polyneuropathy (AIDP), and an axonal variant, which is subdivided into 2 subtypes: acute motor axonal neuropathy (AMAN), and an acute motor sensory axonal neuropathy (AMSAN).2-4 There is an additional rare third type, which is Miller Fischer syndrome that accounts for only 5% of cases. The GBS prevalence is between 0.6-4/100.000 /year,5 with age range from 2 months to 95 years.6 Most patients are between 15-50 years.7,8 The autoimmune nature of the disease is triggered by a nonself-antigen (infectious agent, vaccine) that attacks gangliosides in the axonal membrane by a molecular mimicry mechanism in axonal GBS, but in AIDP, the specific antigen or antibodies are still uncertain.8,9 There is evidence that both cellular and humeral mediated immunity participates in the immune mechanism. The most common infectious agents that participate in the molecular mimicry autoimmune response are Campylobacter jejuni,10,11 cytomegalovirus,12 Epstein barr virus,13 and Mycoplasma pneumoniae.14Much of the research has focused on finding the high risk predisposition of certain people with an infection to develop GBS evidenced by a twin study, linkage disease, genetic, familial, and HLA study.15,16 The HLA antigen system is the name of the loci of genes that encode for the major histocompatibility complex (MHC) in humans. These genes reside on chromosome 6, and encode cell-surface antigen-presenting proteins, along with many other functions. The HLAs corresponding to MHC class I (A, B, and C) present peptides from inside, while HLAs corresponding to MHC class II (DP, DM, DOA, DOB, DQ, and DR) present antigens from outside of the cell to T-lymphocytes. The HLAs corresponding to MHC class III encode components of the complement system.17 In GBS, there is macrophage activation with circulating activated T-lymphocytes evidenced by augmented expression of histocompatibility antigens (HLA-DR), suggesting that there is an association between GBS and HLA alleles.15,16 The HLA typing in GBS was investigated in several studies worldwide suggesting various associations.15,16,18 The aim of the current study is to investigate any association between GBS and HLA-DR.  相似文献   
993.
994.
Background:Psoriasis is a T-cell-mediated autoimmune chronic skin disorder in which an environmental factor, perhaps a viral antigen, induces T cells to produce cytokines. These cytokines stimulate keratinocyte proliferation and production of antigenic adhesion molecules in the dermal blood vessels. Several mediators and hormones have been implicated in keratinocyte hyperproliferation and among these hormones, prolactin (PRL) has been found to have an effect on epithelial cells, lymphocytes and keratinocytes, thus an effect on the etiopathogenesis of psoriasis.Aim:The present study was designed to compare serum PRL levels in psoriatic patients with a control group.Results:Serum PRL levels were significantly increased in patients as compared to the control group (P value: 0.002). There was a positive correlation between pretreatment serum PRL levels and PASI score (r value: 0.379; P value: 0.003). An insignificant association was found between the pretreatment PRL level and serum PRL level after treatment (P value: 0.22). Also, a negative correlation between the duration of psoriasis and serum PRL was seen (r value: -0.008; P value: 0.954).Conclusion:PRL may have a role to play in the etiopathogenesis of psoriasis. However, further studies with large sample size should be carried out so as to validate this hypothesis.  相似文献   
995.
POPDC1 also known as BVES, is a highly conserved transmembrane protein, important for striated muscle function and homeostasis. Pathogenic variants in the POPDC1 gene are associated with limb-girdle muscular dystrophy type 25 (LGMDR25). In the present study, we performed trio-whole exome sequencing (WES) followed by Sanger sequencing on a single family having LGMD clinical features. Protein modeling of all POPDC1 missense variants (POPDC1Pro134Leu, POPDC1Ile193Ser, and POPDC1Ser201Phe) associated with LGMDR25 were performed using Molecular Dynamics (MD) simulation. We identified a homozygous missense variant (c.401C>T; p.Pro134Leu) in the POPDC1 gene. Altered 3D structure, disruptive fluctuation, less compactness, and instability were observed in all the three variants of POPDC1 protein models. In comparison, POPDC1Ser201Phe protein dynamics were more unstable than other variants. Functional study of newly identified variant would add key answers to underlying mechanisms of the disease.  相似文献   
996.
997.
Trigonella foenum-graecum has been extensively used for centuries in traditional medicine systems for the cure of health ailments including diabetes. Improving the medicinal attributes of plants through the elicitation strategy is gaining great interest in the recent past. In the current study, an attempt is made to reveal the role and possible mechanism of action of vitamin C elicit phytochemical-rich aqueous extract of 4th day germinated IM6 genotype fenugreek sprouts in the form of lyophilized powder (IM6E) under both in vitro and in vivo conditions. The IM6E demonstrated strong α-glucosidase activity (95.24 %) and moderate α-amylase and invertase inhibition activities under in vitro conditions. The High Performance Thin Layer Chromatography (HPTLC) based analysis demonstrated that IM6E possess significantly higher concentration of phenolic phytochemical quercetin (0.148 %) as compared to diosgenin and trigonelline bioactive anti-diabetic nutraceuticals. In normal rats after loading with glucose and sucrose, the IM6E administration in a dose-dependent manner significantly reduced the post-prandial hyperglycemia, in a similar fashion as the anti-diabetic drug voglibose as evident from the area under curves (AUC) of oral glucose tolerance test (OGTT) and oral sucrose tolerance test (OSTT) tests. The administration of IM6E in streptozotocin (STZ) induced diabetic rats drastically improved the antioxidant activity of plasma in them as determined by Ferric Reducing Ability of Plasma (FRAP) and the effect was found to be dose-dependent. The oral administration of IM6E in diabetic rats normalized almost all the deregulated biochemical markers like liver enzymes, lipids and significantly decreased higher blood glucose levels with increasing insulin levels as compared to diabetic control. The best concentration of IM6E was found to be 300 mg/kg b.w after 21 days of experimentation. The intra-peritoneal glucose tolerance test (IPGTT) in diabetic rats responded very well to IM6E treatment and 100 mg/kg.b.w. behaved almost like the administration of 0.5U insulin/kg bw, and thus indicating the insulinotropic nature of IM6E. Our findings clearly reveal the use of IM6E for diabetes management and at the same it possesses great potential when combined with voglibose to ameliorate diabetes and its associated complications to a greater extent due to synergistic effects as compared to monotherapy. However, more clinical trials need to be performed before recommending IM6E as an anti-diabetic alternative medicine.  相似文献   
998.
999.

Rheumatoid arthritis (RA) is a slowly progressing inflammatory autoimmune disease. Several features are involved in the RA pathogenesis in addition to environmental and genetic factors. Previously it has been reported that acetyl cholinesterase (AChE) activity is enhanced in old age and may contribute in the progression of RA. The current experimental work was projected to assess the activity of physostigmine (a cholinesterase inhibitor) for treatment of RA. In vitro and in vivo approaches were used for such evaluation. However, enzyme linked immunosorbent assays (ELISA) was performed to determine the concentrations of Prostaglandins E2 (PGE2) and tumor necrosis factor-α in arthritic rats after treatment with physostigmine. Moreover, anti-oxidant assays were employed to calculate the level of super oxide dismutase (SOD) and catalase peroxidase (CAT) in tissue of treated animals. The results claimed the dose dependent protective and stabilizing effect of physostigmine on denaturation of albumin (egg and bovine serum) protein and human red blood cell membrane, respectively, through in vitro studies. Furthermore, the physostigmine (10 and 20 mg/kg) significantly (p?<?0.001) reduced the swelling of paw after induction of arthritis with formaldehyde or complete Freund’s adjuvant (CFA) as compared to arthritic control animals. Moreover, significant (p?<?0.001) reduction in the levels of inflammatory markers (PGE2 and TNF-α) at doses of 10 and 20 mg/kg of physostigmine has been observed in ELISA test. Likewise, there was a prominent rise in levels of SOD and CAT in animals treated with physostigmine. These findings pharmacologically conclude the anti-arthritic effect of physostigmine.

  相似文献   
1000.
Coronary subclavian steal syndrome is an uncommon cause of ischemia recurrence after coronary artery bypass grafting. Endovascular treatment of subclavian artery stenosis or occlusion is increasingly common and appears to offer a safe and effective alternative to surgical revascularization. We report a case of recurrent angina after coronary artery bypass grafting for critical subclavian artery stenosis. The anomalous origin of the vertebral artery from the aortic arch was an indication for endovascular treatment. We discuss the diagnostic difficulties and the management pitfalls of subclavian artery angioplasty in this syndrome.  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