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   739篇
  免费   42篇
耳鼻咽喉   5篇
儿科学   71篇
妇产科学   24篇
基础医学   73篇
口腔科学   23篇
临床医学   84篇
内科学   147篇
皮肤病学   64篇
神经病学   18篇
特种医学   135篇
外科学   31篇
综合类   13篇
预防医学   23篇
眼科学   4篇
药学   36篇
肿瘤学   30篇
  2023年   2篇
  2022年   5篇
  2021年   13篇
  2020年   6篇
  2019年   9篇
  2018年   11篇
  2017年   3篇
  2016年   12篇
  2015年   20篇
  2014年   17篇
  2013年   38篇
  2012年   20篇
  2011年   22篇
  2010年   35篇
  2009年   39篇
  2008年   37篇
  2007年   43篇
  2006年   43篇
  2005年   19篇
  2004年   19篇
  2003年   19篇
  2002年   8篇
  2001年   15篇
  2000年   5篇
  1999年   9篇
  1998年   29篇
  1997年   29篇
  1996年   33篇
  1995年   24篇
  1994年   25篇
  1993年   21篇
  1992年   4篇
  1991年   7篇
  1990年   3篇
  1989年   16篇
  1988年   12篇
  1987年   12篇
  1986年   9篇
  1985年   9篇
  1984年   6篇
  1983年   6篇
  1982年   8篇
  1981年   10篇
  1980年   3篇
  1979年   5篇
  1978年   7篇
  1977年   13篇
  1976年   9篇
  1975年   10篇
  1968年   2篇
排序方式: 共有781条查询结果,搜索用时 15 毫秒
771.
ObjectiveTo identify Mycobacterium tuberculosis (M. tuberculosis) and other acid fast organisms isolated from sputum of HIV positive adult patients with pulmonary disease in Jos, Nigeria.MethodsAcid fast organisms isolated from 80 acid fast bacilli (AFB) positive sputa of HIV positive adult patients suspected for tuberculosis in Jos, Nigeria were identified for members of M. tuberculosis complex (M. tuberculosis, Mycobacterium bovis, Mycobacterium africanum, Mycobacterium canetti, Mycobacterium microti and Mycobacterium caprae) by use of spoligootyping, Multiplex Gen Probe, Hain genotype assay and gene sequencing for spoligotype negative isolates.ResultsSeven different spoligotypes of M. tuberculosis complex were identified from 70/80 (87.5%) total number of isolates. Mycobacterium kansasii (1), Mycobacterium dulvalii (1) Nocardia species (1) and Tsukamurella species (2) were detected from 5/10 spoligotype negative isolates.ConclusionsAlthough M. tuberculosis is the dominant AFB associated with chronic pulmonary disease in Jos, Nigeria, other clinically relevant mycobacteria were also observed in the study. This suggests that other AFB positive microorganisms associated with tuberculosis-like symptoms might be misdiagnosed and incorrectly treated as M. tuberculosis. It is therefore necessary for laboratories in tuberculosis high burden countries to step up diagnostic procedures beyond routine smear microscopy.  相似文献   
772.
Oral Diseases (2010) 16 , 176–184 Objective: The aim of this cross‐sectional study was to evaluate the dental status of 101 Portuguese HIV+ subjects aged 22–71 years (mean = 39) and its association with clinical, socioeconomic, and behavioral variables. Materials and Methods: A calibrated dentist performed clinical examination and collected data on dental caries, periodontal status, dental plaque levels, prosthetic conditions, and need. The volunteers completed questionnaires on socioeconomic and behavioral variables as well as the Oral Health Impact Profile (OHIP‐14) questionnaire. Univariate and multiple logistic regression (MLR) analyses were performed. Results: The mean number of decayed, missing or filled teeth index (DMFT index) was 16.44, standard deviation (s.d.) = 8.42. MLR demonstrated that salaried employee and those with OHIP‐14 ≤4.22, or any/no dental plaque were less prone to have DMFT > median (=17). As regards prosthetic status, 28.8% of the examined individuals used dental prosthesis. MLR demonstrated that HIV+ with DMFT >17 or those who knew they were HIV‐positive for longer than 5 years were more prone to need dental prostheses. The mean OHIP‐14 index was 5.83 (s.d. = 7.79). Conclusions: The dental health status of HIV‐infected Portuguese patients was unsatisfactory and related to clinical, socioeconomic, and behavioral variables.  相似文献   
773.

Background

We assessed ovarian cancer screening outcomes in women with a positive family history of ovarian cancer divided into a low-, moderate- or high-risk group for development of ovarian cancer.

Methods

545 women with a positive family history of ovarian cancer referred to the Ovarian Screening Service at the Royal Marsden Hospital, London from January 2000- December 2008 were included. They were stratified into three risk-groups according to family history (high-, moderate- and low-risk) of developing ovarian cancer and offered annual serum CA 125 and transvaginal ultrasound screening. The high-risk group was offered genetic testing.

Results

The median age at entry was 44 years. The number of women in the high, moderate and low-risk groups was 397, 112, and 36, respectively. During 2266 women years of follow-up two ovarian cancer cases were found: one advanced stage at her fourth annual screening, and one early stage at prophylactic bilateral salpingo-oophorectomy (BSO). Prophylactic BSO was performed in 138 women (25.3%). Forty-three women had an abnormal CA125, resulting in 59 repeat tests. The re-call rate in the high, moderate and low-risk group was 14%, 3% and 6%. Equivocal transvaginal ultrasound results required 108 recalls in 71 women. The re-call rate in the high, moderate, and low-risk group was 25%, 6% and 17%.

Conclusion

No early stage ovarian cancer was picked up at annual screening and a significant number of re-calls for repeat screening tests was identified.  相似文献   
774.
Little is known about the likelihood of curing children with high-dose chemotherapy regimens for treatment of childhood acute lymphoblastic leukemia (ALL) in Turkey. The authors here report their 13 years' experience with original ALL-BFM (Berlin-Franfurt-Münster) 95 protocol in a cohort of 140 Turkish children with ALL. Complete remission rate was 97.7% with a relapse rate of 12.9% and death rate 17.9% during a median follow-up of 69 months. The event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) in these patients at 12 years were 75.0%, 87.1%, and 80.6%, respectively. These results show that ALL-BFM 95 protocol is equally applicable in the experienced centers, even in developing countries without substantial treatment-related toxicity. High rate of infection deaths are to be reduced with correct policies.  相似文献   
775.
Ochratoxin A is one of the most abundant food- contaminating mycotoxins in the world that is immunosuppressive, genotoxic, teratogenic and carcinogenic. Malondialdehyde is a naturally occurring product of lipid peroxidation that is mutagenic and carcinogenic. 8-Hydroxydeoxyguanosine is produced during the interaction of reactive oxygen species and DNA. In this study, Ochratoxin A, malondialdehyde and 8-Hydroxydeoxyguanosine levels of individuals in the study group were measured and results were correlated with each other. Additionally, the correlation of biomarker levels to smoking habit, alcohol and coffee consumption, age and gender of individuals was investigated. As a result of these assessments, a significant correlation was observed between Ochratoxin A exposures and malondialdehyde and 8-Hydroxydeoxyguanosine levels.  相似文献   
776.

Background and purpose:

Abnormal glutamatergic activity is implicated in neurologic and neuropsychiatric disorders. Selective glutamate receptor antagonists were highly effective in animal models of stroke and seizures but failed in further clinical development because of serious side effects, including an almost complete set of symptoms of schizophrenia. Therefore, the novel polyvalent glutamatergic agent 3,5-dibromo-L-phenylalanine (3,5-DBr-L-Phe) was studied in rat models of stroke, seizures and sensorimotor gating deficit.

Experimental approach:

3,5-DBr-L-Phe was administered intraperitoneally as three boluses after intracerebral injection of endothelin-1 (ET-1) adjacent to the middle cerebral artery to cause brain injury (a model of stroke). 3,5-DBr-L-Phe was also given as a single bolus prior to pentylenetetrazole (PTZ) injection to induce seizures or prior to the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) to cause disruption of prepulse inhibition (PPI) of startle (sensorimotor gating deficit).

Key results:

Brain damage caused by ET-1 was reduced by 52%, which is comparable with the effects of MK-801 in this model as reported by others. 3,5-DBr-L-Phe significantly reduced seizures induced by PTZ without the significant effects on arterial blood pressure and heart rate normally caused by NMDA antagonists. 3,5-DBr-L-Phe prevented the disruption of PPI measured 3 days after the administration of ET-1. 3,5-DBr-L-Phe also eliminated sensorimotor gating deficit caused by MK-801.

Conclusion and implications:

The pharmacological profile of 3,5-DBr-L-Phe might be beneficial not only for developing a therapy for the neurological and cognitive symptoms of stroke and seizures but also for some neuropsychiatric disorders.  相似文献   
777.
The murine local lymph node assay (LLNA) has been developed as a test method to assess allergic contact dermatitis. In spite of the validity of the LLNA, attention was drawn to the two disadvantages: use of radioactivity for in vivo measurement of lymph node cell proliferation ([(3)H]-thymidine labeling) and the possibility of false positive results caused by non-specific cell activation as a result of inflammatory processes in the skin (irritation). We aimed to investigate the following non-radioactive endpoints of LLNA: 5-bromo-2'-deoxyuridine (BrdU) incorporation ex vivo and in vivo, in vivo and ex vivo cytokine production with or without phytohemagglutinin (PHA) stimulation. Here, 8-12-week-old female BALB/c mice were treated topically with the strong sensitizer 2,4-dinitrochlorobenzene (DNCB) in acetone:olive oil (AOO, 4:1 [v/v]) at levels of 0.025, 0.05, 0.01, or 0.25% (w/v). Ear thickness was also measured to determine the differentiation index (DI) indicating the proportion of non-specific activation due to irritating properties of test compound. At the concentration of 0.05%, stimulation index (SI) value was found to be 3 for DNCB based on in vivo and ex vivo BrdU incorporation. The results of the in vivo and ex vivo non-radioactive LLNA assays were compatible both with each other and with previous radioactive LLNA data. Our results indicate that non-radioactive endpoints may be used as an alternative to the [(3)H]-thymidine LLNA. The levels of T(H)1 cytokines (IL-2 and IFNγ) and T(H)2 cytokines (IL-4 and IL-5) in lymph node cell cultures were significantly (P? 1, the applied concentrations of DNCB caused only allergic effect but not any irritant effect. This study reports that the use of these non-radioactive endpoints can assess allergic contact dermatitis caused by chemicals.  相似文献   
778.
Objectives. Rheumatoid arthritis (RA) is characterized by the chronic inflammation of the synovial joints resulting from the hyperplasia of synovial cells and the infiltration of lymphocytes, macrophages and plasma cells. Currently, the aetiology of RA is not known, and new treatment modalities are needed to prevent the disease progression. Apoptosis induction of synovial cells through the use of death ligands has been explored as a treatment modality for RA. Thus, the primary objective of this study was the testing of the efficacy of adenovirus delivery of human TRAIL (Ad5hTRAIL) for the treatment of patients with RA. Methods. Primary synovial cell cultures were established from eight patients with RA. Adenovirus permissiveness of synovial cells was determined by the infection of synoviocytes with adenovirus vector encoding green fluorescent protein (AdEGFP). TRAIL sensitivity of synoviocytes was assessed through the infection with Ad5hTRAIL vector using Live/Death Cellular Viability/Toxicity kit from Molecular Probe. TRAIL receptor profiles of synoviocytes were revealed by real-time RT-PCR assays followed by flow cytometric analyses. Results. While the presence of TRAIL death receptors were necessary for the induction of cell death, high levels of TRAIL-R4 decoy receptor expression on surface were correlated with TRAIL resistance. A DcR2 siRNA approach in combination with Ad5hTRAIL infection eliminated apoptosis-resistant RA synovial fibroblasts. Conclusion. Because a DcR2 siRNA approach in combination with Ad5hTRAIL infection exterminated RA synoviocytes to a greater extent than Ad5hTRAIL alone, the modulation of TRAIL receptor expression might be a new gene therapy strategy to sensitize RA synoviocytes to TRAIL.  相似文献   
779.
Chest pain, a frequent complaint during childhood, rarely originates from a cardiac pathology. Although it usually is idiopathic, it also could be associated with psychogenic, musculoskeletal, respiratory, and digestive disorders. This study aimed to investigate a possible relation between bone mineral density and chest pain in children. Bone mineral density and bone metabolism parameters were measured for 50 children with chest pain, and the findings were compared with those for 40 age- and sex-matched healthy children. Most of the cases (64%) were in the idiopathic group, and musculoskeletal chest pain was the second most frequent complaint (12%). Although bone mineral densities and osteocalcin levels did not differ significantly between the whole chest pain group and the control group, both were found to be lower in the musculoskeletal chest pain group than in other groups and the control group (p < 0.05). Musculoskeletal chest pain may be related to reduced bone mineral metabolism, and monitoring of risk factors is of particular importance.  相似文献   
780.
Rho kinase (ROCK) and nitric oxide (NO) are important targets in cardiovascular diseases. Therefore, we investigated the possible influence of NO on Rho kinase (ROCK-2 isoform) expressions in cultured rat coronary microvascular endothelial cells. The cells were isolated from Wistar rats on a Langendorff system, and were incubated overnight (approximately 16 h) with an NO generator, A-23187 (10 to 10 M), NO donors, such as sodium nitroprusside (10 to 10 M), glyceryl trinitrate (10 to 10 M), 2,2'-(hydroxynitrosohydrazono)bis-ethanimine (10 to 10 M), and NaNO2 (10 to 10 M) or a nitric oxide synthase (NOS) inhibitor, N-nitro-L-arginine methylester (2 x 10 M), or two ROCK inhibitors, (+)-(R)-trans-4-(1-aminoethyl)- N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride monohydrate (Y-27632, 10 M) and fasudil (10 M) in the absence or presence of thrombin (4 U/mL). ROCK-2 and endothelial NOS (eNOS) expressions were detected by Western blotting. Moreover, nitrite/nitrate levels were detected by Griess method in the presence of the ROCK inhibitors. The NO donors and the NO generator had no significant effects on ROCK-2 expression. Y-27632 and fasudil did not alter eNOS expression and NO production. Nitrite/nitrate levels were 4.4 +/- 0.32 microM in control and 4.0 +/- 0.93 microM and in Y-27632 group. These results demonstrate that prolong NO donation could not suppress the expression of ROCK-2 protein, and the ROCK inhibitor did not change e-NOS expression and NO production in the cultured rat coronary microvascular endothelial cells.  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