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   1298篇
  免费   87篇
  国内免费   15篇
耳鼻咽喉   6篇
儿科学   33篇
妇产科学   41篇
基础医学   149篇
口腔科学   22篇
临床医学   161篇
内科学   289篇
皮肤病学   29篇
神经病学   90篇
特种医学   47篇
外科学   104篇
综合类   36篇
一般理论   1篇
预防医学   113篇
眼科学   13篇
药学   139篇
中国医学   15篇
肿瘤学   112篇
  2024年   1篇
  2023年   25篇
  2022年   71篇
  2021年   91篇
  2020年   48篇
  2019年   70篇
  2018年   57篇
  2017年   54篇
  2016年   51篇
  2015年   51篇
  2014年   59篇
  2013年   61篇
  2012年   102篇
  2011年   118篇
  2010年   44篇
  2009年   50篇
  2008年   81篇
  2007年   68篇
  2006年   51篇
  2005年   66篇
  2004年   51篇
  2003年   36篇
  2002年   32篇
  2001年   6篇
  2000年   8篇
  1999年   7篇
  1998年   5篇
  1997年   1篇
  1996年   5篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   4篇
  1982年   2篇
  1979年   1篇
  1973年   1篇
  1972年   1篇
  1949年   1篇
排序方式: 共有1400条查询结果,搜索用时 15 毫秒
31.
32.
BACKGROUND: We have previously suggested that helminthic infections make the host more susceptible to HIV infection and enhance its progression due to the chronic immune activation they cause. OBJECTIVE: To study the effect of antihelminthic treatment on HIV plasma viral load (VL) in HIV- and helminth-infected individuals living in Ethiopia. METHODS: Fifty-six clinically asymptomatic HIV-1-infected individuals, 31 (55%) of whom were also infected with helminths, were studied. All participants received antihelminthic treatment at baseline and at 3 and 6 months. Worm egg excretion, HIV plasma VL, and T-cell subsets were determined at baseline and 6 months after treatment. RESULTS: The mean age, number of CD4 T cells, and gender distribution were similar in the helminth-infected and -noninfected groups. At baseline, HIV plasma VL was strongly correlated to the number of eggs excreted (p <.001) and was higher in individuals infected with more than one helminth (5.28 +/- 0.35 versus 4.30 +/- 1.13 log RNA copies/mL, respectively; p =.16). After treatment of helminths, the 6-month change in HIV plasma VL was significantly different between the successfully treated group and the persistently helminth-positive group (p =.04) CONCLUSIONS: Helminth "load" is correlated to HIV plasma VL, and successful deworming is associated with a significant decrease in HIV plasma VL. The results of the current study, if confirmed in a larger study, may have important implications for slowing disease progression and reducing risks of transmission.  相似文献   
33.
Human immunodeficiency virus (HIV-1) enters target cells by binding its gp120 exterior envelope glycoprotein to CD4 and one of the chemokine receptors, CCR5 or CXCR4. CD4-induced (CD4i) antibodies bind gp120 more efficiently after CD4 binding and block the interaction with the chemokine receptor. Examples of CD4i antibodies are limited, and the prototypes of the CD4i antibodies exhibit only weak neutralizing activity against primary, clinical HIV-1 isolates. Here we report the identification of a novel antibody, E51, that exhibits CD4-induced binding to gp120 and neutralizes primary HIV-1 more efficiently than the prototypic CD4i antibodies. The E51 antibody blocks the interaction of gp120-CD4 complexes with CCR5 and binds to a highly conserved, basic gp120 element composed of the beta 19-strand and surrounding structures. Thus, on primary HIV-1 isolates, this gp120 region, which has been previously implicated in chemokine receptor binding, is accessible to a subset of CD4i antibodies.  相似文献   
34.
35.
Meckel–Gruber (MKS) syndrome is a lethal autosomal abnormality diagnosed most commonly from classical findings on ultrasound scan after the late first trimester. There are few reports of cases followed up antenatally until delivery. We report here one of the largest series of 19 cases diagnosed antenatally from as early as 11 weeks gestation with 5 born alive. Of the 12 cases followed up antenatally, 7 were stillbirths while 5 were live births. The absence of obvious polycystic kidneys and severe oligohydramnios were prognostic features consistent with a live birth; however, mortality was 100% within a few weeks of delivery. The incidence of 2/1000 live births in the local population is similar to that reported from similar groups where consanguinity is more than 40%. The recurrence rate was high with 50% of the parous patients having had an affected baby. We conclude that diagnosis in early pregnancy does not require the classical triad of encephalocele, polydactyly and polycystic kidneys as some of these features do not manifest on imaging until much later.  相似文献   
36.
Aim: To evaluate the clinical usefulness of maternal serum interleukin-6 for the detection of subclinical chorioamnionitis and in the prediction of the latency period in patients with preterm premature rupture of membrane (PPROM).

Methods: The study group included 60 patients at 24–34 weeks of gestation complaining of PPROM. Laboratory investigations included serial measurements of IL-6, TLC and CRP. Conservative management was carried out till 36 weeks unless delivery was indicated beforehand. The main outcome measures were the latency period and the occurrence of subclinical chorioamnionitis.

Results: The mean gestational age at presentation was 30.9 weeks and 35.2 weeks at delivery. The mean IL-6 level at presentation was 4.7?pg/ml. There was no correlation between IL-6 at presentation and the latency period. In addition, those diagnosed as having subclinical chorioamnionitis by placental histopathology had significantly higher levels of IL-6 at delivery. Taking IL-6 level cutoff point of 8.5?pg/ml, histological chorioamnionitis, RDS and NICU admission were significantly higher above that level while neonatal birth weight, Apgar scores at one and five minutes were significantly lower.

Conclusion: Maternal serum IL-6 at the time of PPROM has no correlation to the latency period while IL-6 levels at the time of delivery have significant correlation to the subclinical chorioamnionitis and neonatal outcome measures.  相似文献   
37.
Treatment with dopamine and other dopamine D2 receptor agonists has been shown to induce cell death through activation of caspase-3 pathway. However, initial step that leads to the activation of caspase-3 in D2 receptor-mediated apoptotic pathway remains unclear. Recently, it was shown that a spliced variant of Galphai2 protein (sGalphai2) forms intracellular complex with D2 receptors by protein-protein interaction and that D2 drugs treatment causes the liberation of sGalphai2 protein from complex. Now, we show that the unbound form of sGalphai2 protein is able to activate caspase-3 pathway in baby hamster kidney (BHK) cells. Expression of sGalphai2 protein in BHK cells led to the production of active form of caspase-3 and activation of p38 mitogen-activated protein kinase (p38 MAPK) and extracellular regulated kinase 1/2 (ERK1/2). Co-expression of sGalphai2 with either D2 short (D2S) or D2 long (D2L) isoforms of dopamine D2 receptors blocked the activation of caspase-3 pathway. Thus, our results demonstrate that high level of unbound sGalphai2 protein can affect the cell survival and engagement of this protein with D2 receptors can block this process. It is suggested that this process may be a crucial step in the initiation of D2 receptor-mediated cellular apoptosis through this pathway.  相似文献   
38.
Hepatitis C is a global public health problem, and Pakistan is the second largest country in the globe with highest prevalence rate of hepatitis C virus (HCV). Until 2014, pegylated interferon (PEG-IFN) plus ribavirin (RBV) has been the standard therapy for HCV, however, owing to its adverse side effects and very low sustained virologic response (SVR) rates therapeutics trend is shifted toward direct-acting antivirals. Tripartite motif containing 22 (TRIM22) is a dynamic antiviral protein that can inhibit multiple viruses in vivo. Expression of TRIM22 mRNA has been linked to outcome of PEG-IFN and ribavirin therapy, where its higher expression leads to rapid virus clearance. However, in terms of therapy with direct-acting antiviral (DAA) or double DAA, impact of TRIM22 expression is largely unknown. These new drugs show more than 90% of SVR rates and lesser side effects and have proven to be better than IFN therapy. Endogenous IFN system suppresses various pathogens through the induction of antiviral effectors termed as interferon-stimulating genes (ISGs). We have studied the expression levels of one of these antiviral effectors, TRIM22 in response to sofosbuvir (SOF) and daclatasvir (DAC) in combination with RBV, using quantitative PCR in the peripheral blood mononuclear cells (PBMCs) of HCV-infected patients. We have observed sustained virus clearance in more than 90% of patients treated with DAA and double DAA and have seen the expression of TRIM22 to be higher in patients who attained SVR as compared to the untreated patients. We have also observed downregulation of TRIM22 in patients who failed to attain rapid virus clearance, and upregulation in those who achieved rapid clearance of virus. Genetic factors that determine the lower TRIM22 expression in these patients are needed to be explored that may also play a role in lower response to anti-HCV therapy. Endogenous IFN system and effects of antiviral proteins in response to DAA therapy is needed to be studied in order to better understand the host response toward these drugs to make them more effective.  相似文献   
39.
In recent years, several genes have been implicated in the variable disease presentation of global developmental delay (GDD) and intellectual disability (ID). The endoplasmic reticulum membrane protein complex (EMC) family is known to be involved in GDD and ID. Homozygous variants of EMC1 are associated with GDD, scoliosis, and cerebellar atrophy, indicating the relevance of this pathway for neurogenetic disorders. EMC10 is a bone marrow-derived angiogenic growth factor that plays an important role in infarct vascularization and promoting tissue repair. However, this gene has not been previously associated with human disease. Herein, we describe a Saudi family with two individuals segregating a recessive neurodevelopmental disorder. Both of the affected individuals showed mild ID, speech delay, and GDD. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify candidate genes. Further, to elucidate the functional effects of the variant, quantitative real-time PCR (RT-qPCR)-based expression analysis was performed. WES revealed a homozygous splice acceptor site variant (c.679-1G>A) in EMC10 (chromosome 19q13.33) that segregated perfectly within the family. RT-qPCR showed a substantial decrease in the relative EMC10 gene expression in the patients, indicating the pathogenicity of the identified variant. For the first time in the literature, the EMC10 gene variant was associated with mild ID, speech delay, and GDD. Thus, this gene plays a key role in developmental milestones, with the potential to cause neurodevelopmental disorders in humans.  相似文献   
40.
Even though entirely digitized microscopic tissue sections (whole slide images, WSIs) are increasingly being used in histopathology diagnostics, little data is still available on the effect of this technique on pathologists' reading time. This study aimed to compare the time required to perform the microscopic assessment by pathologists between a conventional workflow (an optical microscope) and digitized WSIs. WSI was used in primary diagnostics at the Laboratory for Pathology Eastern Netherlands for several years (LabPON, Hengelo, The Netherlands). Cases were read either in a traditional workflow, with the pathologist recording the time required for diagnostics and reporting, or entirely digitally. Reading times were extracted from image management system log files, and the digitized workflow was fully integrated into the laboratory information system. The digital workflow saved time in the majority of case categories, with prostate biopsies saving the most (68% time gain). Taking into account case distribution, the digital workflow produced an average gain of 12.3%. Using WSI instead of conventional microscopy significantly reduces pathologists' reading times. Pathologists must work in a fully integrated environment to fully reap the benefits of a digital workflow.  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