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   689篇
  免费   54篇
  国内免费   2篇
耳鼻咽喉   3篇
儿科学   72篇
妇产科学   6篇
基础医学   66篇
口腔科学   6篇
临床医学   47篇
内科学   117篇
皮肤病学   34篇
神经病学   61篇
特种医学   16篇
外科学   69篇
综合类   15篇
预防医学   32篇
眼科学   50篇
药学   41篇
中国医学   9篇
肿瘤学   101篇
  2023年   8篇
  2022年   20篇
  2021年   39篇
  2020年   24篇
  2019年   28篇
  2018年   30篇
  2017年   30篇
  2016年   30篇
  2015年   22篇
  2014年   29篇
  2013年   34篇
  2012年   63篇
  2011年   62篇
  2010年   32篇
  2009年   22篇
  2008年   24篇
  2007年   22篇
  2006年   24篇
  2005年   33篇
  2004年   15篇
  2003年   34篇
  2002年   25篇
  2001年   16篇
  2000年   13篇
  1999年   11篇
  1998年   6篇
  1997年   6篇
  1995年   2篇
  1994年   1篇
  1992年   2篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   1篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1977年   4篇
  1976年   2篇
  1974年   1篇
  1973年   2篇
  1971年   3篇
  1968年   1篇
  1964年   1篇
排序方式: 共有745条查询结果,搜索用时 15 毫秒
71.
72.
The use of fluorescence diagnosis as a modern cancer diagnostic modality is rapidly gaining importance in the field of urology. It is based on the detection of distinctive light emission of tissues sensitized by fluorescent dyes, commonly referred to as photosensitizers, after irradiation with a specific light source. Therefore, the search for specific fluorescent dyes with high sensitivity and specificity for bladder cancer is constantly being sought after. The aim of this study is to investigate the use of a new formulation consisting a mixture of chlorin e6 and polyvinylpyrrolidone (Ce6-PVP) for the detection of human bladder cancer cells (MGH) implanted on the chick chorioallantoic membrane (CAM) model. Uptake kinetics studies were quantitatively determined for both systemic and topical administrations of Ce6-PVP to the normal CAM as well as the MGH human bladder tumor implanted on CAM using fluorescence imaging technique. Rapid elimination of Ce6-PVP was displayed following topical application compared to systemic administration in the normal CAM system. Ce6-PVP was found to localize selectively in the xenografted bladder tumor in contrast to the CAM tissue. Neither dark toxicity nor irritancy was observed on the CAM tissue at the dose of 2 mg/kg Ce6-PVP. In conclusion, the Ce6-PVP formulation appeared to have the potential as a fluorescent marker for fluorescence diagnosis of human bladder cancer.  相似文献   
73.
A new selective and sensitive high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of natamycin in rabbit tears using amphotericin B as internal standard (IS). Chromatographic separation was achieved on a Luna Cyano column (100 mm × 2 mm, 3 μm) using ammonium acetate buffer (pH 4; 3.5mM): methanol (10:90, v/v) as the mobile phase. The run time was 5 min. Detection was performed by negative ion electrospray ionization in multiple reaction monitoring (MRM) mode. The calibration curve was linear over the concentration range from 25 to 800 ng/ml, and lower limit of detection of 12.5 ng/ml. The accuracy and precision of the method were within the acceptable limit of ± 20% at the lower limit of quantitation and ± 15% at other concentrations. Natamycin was stable during the battery of stability studies viz., bench-top, auto-sampler, freeze/thaw cycles and 30 days storage in a freezer at -70 ± 10 °C. The method was successfully applied to the ocular pharmacokinetic studies of natamycin eye drops in New Zealand rabbit tears.  相似文献   
74.
Clinical Rheumatology - To present single centre experience on the efficacy and safety of similar biologic of rituximab in patients with granulomatosis with polyangiitis (GPA). This was a...  相似文献   
75.
Objective: The co-occurrence of sleep problems, cognitive impairment, and depression among the elderly suggests that these three conditions are likely to be interrelated. Recent findings suggest that depressive symptoms moderate the relationship between sleep problems and cognitive impairment in elderly people but methodological problems have led to inconsistent conclusions. The present study aims to better understand the relationship between sleep quality, depressive symptoms, and cognitive function. Method: We administered the Repeatable Battery for the Assessment of Neuropsychological Status and self-report measures of sleep quality and depression to 380 elderly participants (Mage = 68 years, SD= 5.7). Bootstrapped moderation analyses were conducted to examine the role of depressive symptoms in the relationship between sleep and various aspects of cognitive function. Results: This moderation effect was significant in the domains of delayed memory (ΔR2 = .01, F = 4.5, p = .04), language (ΔR2 = .01, F = 4.6, p = .035), and general cognitive status (ΔR2 = .01, F = 5.3, p = .02). However, unlike previous studies, higher sleep quality corresponded to better outcomes in delayed memory, language abilities, and general cognitive status in participants with low levels of depressive symptoms. No significant relationship between sleep quality and any cognitive function was observed among participants with high levels of depressive symptoms. Conclusions: Among individuals who reported low levels of depressive symptoms, sleep quality was positively related to cognitive performance in the domains of delayed recall, language, and general cognitive status. However, sleep quality was not significantly associated with cognitive abilities in these domains among participants with elevated levels of depressive symptoms; participants had relatively poor outcomes in these cognitive domains regardless of their sleep quality.  相似文献   
76.

Background

Renal cell carcinoma (RCC) is histopathologically heterogeneous with clear cell and papillary the most common subtypes. The most frequent molecular abnormality in clear cell RCC is VHL inactivation but promoter methylation of tumour suppressor genes is common in both subtypes of RCC. To investigate whether RCC CpG methylation status was influenced by histopathology and VHL status we performed high-throughput epigenetic profiling using the Illumina Goldengate Methylation Array in 62 RCC (29 RCC from von Hippel-Lindau (VHL) disease patients, 20 sporadic clear cell RCC with wild type VHL and 13 sporadic papillary RCC).

Results

43 genes were methylated in >20% of primary RCC (range 20–45%) and most (37/43) of these had not been reported previously to be methylated in RCC. The distribution of the number of methylated CpGs in individual tumours differed from the expected Poisson distribution (p < 0.00001; log-likelihood G test) suggesting that a subset of RCC displayed a CpG Island Methylator Phenotype. Comparison of RCC subtypes revealed that, on average, tumour specific CpG methylation was most prevalent in papillary RCC and least in VHL RCC. Many of the genes preferentially methylated in pRCC were linked to TGFβ or ERK/Akt signalling.

Conclusion

These findings demonstrate differing patterns of tumour-specific CpG methylation in VHL and non VHL clear cell RCC and papillary RCC, and identify multiple novel potential CpG methylation biomarkers for RCC.  相似文献   
77.

Context:

This study was carried out as a part of an internal audit and is the largest series of patients having keratoglobus, published in the literature. Poor visual acuity of the patients indicates the blinding nature of the disease.

Aims:

We report our experience with patients having keratoglobus at a tertiary eye care center in India.

Settings and Design:

Retrospective study.

Materials and Methods:

We analyzed adults and pediatric patients (<16 years) with keratoglobus, seen during 2008–2012. The age, gender, consanguinity, presenting ocular signs, ocular and systemic associations, visual acuity, corneal topography, and surgeries were documented.

Results:

Forty-eight patients (mean age 22 ± 15 years, 31 males) having keratoglobus were analyzed. 21 patients (42 eyes) were <16 years. Twelve eyes (16 events) had positive history of trauma. The presenting clinical signs were corneal scars/scars of tear repair (15 eyes), hydrops, healed and acute (14 eyes) and corneal or globe rupture (9 eyes). Best-corrected visual acuity was >20/40 in 6/42 (14.3%) pediatric eyes and 15/53 (28.30%) adults. Visual acuity ranging from counting of fingers to no light perception was noted in 20/53 (37.74%) adults and 21/42 (50%) pediatric patients; 13/20 (65%) with blue sclera and 8/22 eyes (36.37%) without blue sclera. Vernal keratoconjunctivitis was present in one pediatric patient. Choroidal osteoma, retinitis pigmentosa, and retinal detachment were present in adults. Surgeries performed were corneal tear repair (5 eyes), tissue adhesive application (2 eyes), descematopexy (4 eyes) and penetrating keratoplasty (PK - 8 eyes: Three had post-PK glaucoma, graft failure-one eye, 4 patients wore scleral lens - prosthetic replacement of the ocular surface ecosystem).

Conclusions:

About 50% of pediatric eyes (65% having blue sclera) had no functional vision. Trivial trauma was responsible for corneal rupture indicating need for protective glasses. About 50% patients had post-PK glaucoma though grafts were clear.  相似文献   
78.
Alport syndrome (AS) is an inherited disorder of basement membranes caused by mutations affecting specific proteins of the type IV collagen family, presenting with nephropathy and extrarenal manifestations such as sensorineural deafness and ocular anomalies. Ten percentage to 15% of the patients with AS have autosomal recessive (ARAS) due to mutation in either COL4A3 or COL4A4 gene. We report a novel mutation in the COL4A3 gene in an Indian family with ARAS. The above‐mentioned genetic anomaly was a missense variation in exon 26 of the COL4A3 gene (chr2:228137797G>A; c.1891G>A) that resulted in the amino acid substitution of Arginine for Glycine at codon 631 (p.Gly631Arg) that was present in the heterozygous state in the asymptomatic parents and homozygous state in the male offspring who presented with early‐onset end‐stage renal disease, lenticonus and hearing loss. The patient (male offspring) underwent successful renal transplantation with his mother as a donor.  相似文献   
79.
Pancreatic transplantation is currently the only effective cure for Type 1 diabetes mellitus. It allows long-term glycemic control without exogenous insulin and amelioration of secondary diabetic complications. In India, pancreas transplant has not yet established with only a single successful transplant reported so far in the literature. We report a 24-year-old Type 1 diabetic patient with renal failure who underwent a simultaneous pancreas kidney transplant. On postoperative day 15, he had leak from the graft duodenal stump for which a tube duodenostomy and proximal diversion enterostomy was done. He had a high output pancreatic fistula following the procedure which was managed conservatively. The tube duodenostomy was removed at three and half months and enterostomy closure with restoration of bowel continuity was done at 6 months. After a follow up of 7 months, patient is doing well with a serum creatinine of 0.8 mg/dl and normal blood sugars, not requiring any exogenous insulin or oral hypoglycemic drugs. Managing patients with graft duodenal complications after pancreas transplant is challenging. Tube duodenostomy is a safe option in management of duodenal leak, although can lead to a persistent pancreatic fistula. A proximal diversion enterostomy allows early oral feeding and avoids the cost as well as the long term complications associated with parenteral nutrition.  相似文献   
80.
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease confirmed at postmortem. Those at highest risk are professional athletes who participate in contact sports and military personnel who are exposed to repetitive blast events. All neuropathologically confirmed CTE cases, to date, have had a history of repetitive head impacts. This suggests that repetitive head impacts may be necessary for the initiation of the pathogenetic cascade that, in some cases, leads to CTE. Importantly, while all CTE appears to result from repetitive brain trauma, not all repetitive brain trauma results in CTE. Magnetic resonance imaging has great potential for understanding better the underlying mechanisms of repetitive brain trauma. In this review, we provide an overview of advanced imaging techniques currently used to investigate brain anomalies. We also provide an overview of neuroimaging findings in those exposed to repetitive head impacts in the acute/subacute and chronic phase of injury and in more neurodegenerative phases of injury, as well as in military personnel exposed to repetitive head impacts. Finally, we discuss future directions for research that will likely lead to a better understanding of the underlying mechanisms separating those who recover from repetitive brain trauma vs. those who go on to develop CTE.  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