全文获取类型
收费全文 | 2723篇 |
免费 | 181篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 91篇 |
妇产科学 | 43篇 |
基础医学 | 353篇 |
口腔科学 | 58篇 |
临床医学 | 245篇 |
内科学 | 476篇 |
皮肤病学 | 56篇 |
神经病学 | 181篇 |
特种医学 | 59篇 |
外国民族医学 | 1篇 |
外科学 | 559篇 |
综合类 | 99篇 |
预防医学 | 198篇 |
眼科学 | 47篇 |
药学 | 180篇 |
中国医学 | 23篇 |
肿瘤学 | 226篇 |
出版年
2023年 | 29篇 |
2022年 | 77篇 |
2021年 | 114篇 |
2020年 | 69篇 |
2019年 | 67篇 |
2018年 | 78篇 |
2017年 | 54篇 |
2016年 | 68篇 |
2015年 | 94篇 |
2014年 | 106篇 |
2013年 | 137篇 |
2012年 | 198篇 |
2011年 | 212篇 |
2010年 | 94篇 |
2009年 | 99篇 |
2008年 | 169篇 |
2007年 | 173篇 |
2006年 | 146篇 |
2005年 | 141篇 |
2004年 | 117篇 |
2003年 | 97篇 |
2002年 | 90篇 |
2001年 | 65篇 |
2000年 | 64篇 |
1999年 | 42篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 15篇 |
1995年 | 22篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 10篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1979年 | 14篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1975年 | 12篇 |
1974年 | 8篇 |
1971年 | 5篇 |
1970年 | 5篇 |
排序方式: 共有2915条查询结果,搜索用时 0 毫秒
81.
82.
Developing and validating a new nomogram for diagnosing bladder outlet obstruction in women 下载免费PDF全文
Eskinder Solomon Habiba Yasmin Megan Duffy Tanwir Rashid Emmanuel Akinluyi Tamsin J. Greenwell 《Neurourology and urodynamics》2018,37(1):368-378
Objective
To develop and validate a nomogram for assessing bladder outlet obstruction (BOO) in women derived from concurrent Pdet.Qmax and Qmax based on radiographic evidence of increased urethral resistance.Patients and Methods
Retrospective analysis of prospectively acquired video‐urodynamics and clinical data of 185 women (development cohort) was performed. The Pdet.Qmax were plotted against Qmax and cluster analysis was performed to determine an axis that best divided the definitively obstructed and unobstructed. Using data from a further 350 women (validation cohort), the sensitivity and specificity of the derived criterion was calculated. Finally, the data from both groups was pooled together and using binary logistic regression analysis, a nomogram was produced.Results
Of the 535 patients in the two cohorts, (122 [22.8%]) demonstrated radiographic evidence of BOO. Cluster analysis identified the axis that best separates the radiographically obstructed and unobstructed as Pdet.Qmax = 2*Qmax. Using the data from the validation cohort, the sensitivity and specificity for this was calculated as 0.94 and 0.93, respectively. A nomogram, representing the probability of BOO for concurrent Pdet.Qmax and Qmax measurements was derived by pooling data from both cohorts. Alternatively, a female BOO index (BOOIf) may be calculated mathematically using the formula BOOIf = Pdet.Qmax ? 2.2*Qmax, that is, BOOIf < 0, <10% probability of obstruction, BOOIf > 5 likely obstructed (50%) and If BOOIf > 18, obstruction almost certain (>90%).Conclusion
A female BOO nomogram (the SG nomogram) with high sensitivity and specificity is proposed. The nomogram can be used to stratify the degree of BOO or assess response to treatment. 相似文献83.
84.
A. Rashid Choudhury Mohamed S. Al Amin Kamal A. Chaudhri Khalaf R. Al Moutaery 《Child's nervous system》1995,11(2):115-117
A 5-year-old girl presented with a 1-year history of a subcutaneous swelling in the right parietal region. There were no cerebral symptoms or signs. Plain X-ray of the skull showed a lytic bony lesion with sclerotic margin. Computed tomography showed a hypodense, osteolytic lesion with thinned and bulged inner and outer skull tables with intact continuity. There was no intracranial lesion. At operation, the mass was found to be pink and granular, and was totally enucleated. Histology revealed it to be a benign osteoblastoma. 相似文献
85.
Nayil K Makhdoomi R Ramzan A Zahoor S Rasool M Wani A Dhar A Mubeen B Singh S Bhat R Kirmani A 《Pediatric neurosurgery》2011,47(1):31-37
Brain tumors in children represent the second most frequent tumors in this age group after hematologic malignancies. We highlight the demographic pattern after retrospective analysis of brain tumors in children from geographically and ethnically distinct Kashmir Valley managed in our center between 2000 and 2009. We had a total of 248 pediatric patients with brain tumors. The parameters analyzed were age, gender, location of tumors and histopathological subtypes as well as WHO grade of tumor. We also did a comparison between the frequencies of common varieties of tumor in the first and second 5-year periods. We found that 111 tumors (44.75%) were supratentorial, and 137 (55.25%) were infratentorial. The male-to-female ratio was 1.4:1. The proportions of low-grade and high-grade tumors were 60 and 40%, respectively. The most common tumor in our series was astrocytoma. The most common tumors in the supratentorial and infratentorial compartments were craniopharyngioma and medulloblastoma, respectively. Our experience reflects a different demographic profile of pediatric brain tumors as compared with other regions of the world. 相似文献
86.
Bajaj P Tang X Saif TA Bashir R 《Journal of biomedical materials research. Part A》2010,95(4):1261-1269
We examined the effect of substrate stiffness on the beating rate, force of contraction, and cytoskeletal structure of embryonic chicken cardiac myocytes by culturing them on laminin-coated polyacrylamide (PA) substrates. Cells cultured on PA substrates with elasticity comparable to that of the native myocardium (18 kPa) exhibited the highest beating rate during the first few days of culture. The initial beating rate of individual cells on all the substrates varied significantly but began to converge within 5 days. We also examined the focal adhesions (FAs) and cytoskeletal structure on different substrates via confocal microscopy and found a higher percentage of FAs on tissue culture (TC) plastic dishes compared with the softer PA gels. Furthermore, highly aligned sarcomeric striations were clearly visible on 18 kPa, 50 kPa, and TC dish, whereas cells on 1 kPa only showed nonaligned diffused striations. The force of contraction on these substrates was measured using a micro-electromechanical system force sensor, which showed that the force of contraction for the cells on TC dishes (F = 71.30 ± 6.38 nN) was significantly larger than those cultured on the 18-kPa PA gel (F = 30.16 ± 3.83 nN). This is most likely due to the formation of higher percentage of FAs on the TC dishes compared with fewer FAs on the softer gels. Our cumulative findings can have a significant impact on the design of 3D cardiac tissue engineered scaffolds. 相似文献
87.
Various studies have shown that the Asian fish tapeworm, Bothriocephalus acheilognathi causes great economic loss in hatcheries, fish farms as well as in lakes. In order to understand the seasonal variation of
infection in a nutrient-enriched lake, parasitological investigation was carried out in the indigenous cyprinid fish, Schizothorax niger Heckel 1838 from September, 2008 to August, 2009. Overall, this study revealed definite seasonality of infection (p < 0.05), with greater infection in summer (prevalence = 39.5%) and lesser in winter (prevalence = 8.1%). The prevalence among
different seasons revealed significant differences (p < 0.05). Sex was not an important factor influencing the prevalence of the Asian tapeworm. A strong positive correlation
(Pearson’s correlation, r = 0.7; p = 0.02) between total length of S. niger and number of Asian fish tapeworms was observed. Similarly, a strong positive correlation existed between weight of fish
and number of tapeworms (Pearson’s correlation, r = 0.7; p = 0.005). Prevalence and mean abundance were positively and significantly correlated with water temperature (r = 0.8, p < 0.01 and r = 0.8, p < 0.01, respectively). Thus seasonal dynamics, total length and weight of the host significantly influenced the tapeworm
infection. The above findings will be useful in devising the appropriate control strategies for the Asian tapeworm in wild
fish in Kashmir valley as well as in similar climatic zones of other parts of the world. Also, information from this study
will be used to assess the spread and extent of B. acheilognathi which is a potential threat to the indigenous fish fauna of Anchar Lake. 相似文献
88.
TRARESA: a tissue microarray-based hospital system for biomarker validation and discovery 总被引:2,自引:0,他引:2
Das K Mohd Omar MF Ong CW Bin Abdul Rashid S Peh BK Putti TC Tan PH Chia KS Teh M Shah N Soong R Salto-Tellez M 《Pathology》2008,40(5):441-449
Formalin fixed and paraffin embedded tissue (FFPE) collections in pathology departments are the largest resource for retrospective biomedical research studies. Based on the literature analysis of FFPE related research, as well as our own technical validation, we present the Translational Research Arrays (TRARESA), a tissue microarray centred, hospital based, translational research conceptual framework for both validation and/or discovery of novel biomarkers. TRARESA incorporates the analysis of protein, DNA and RNA in the same samples, correlating with clinical and pathological parameters from each case, and allowing (a) the confirmation of new biomarkers, disease hypotheses and drug targets, and (b) the postulation of novel hypotheses on disease mechanisms and drug targets based on known biomarkers. While presenting TRARESA, we illustrate the use of such a comprehensive approach. The conceptualisation of the role of FFPE-based studies in translational research allows the utilisation of this commodity, and adds to the hypothesis-generating armamentarium of existing high-throughput technologies. 相似文献
89.
Well-differentiated neuroendocrine tumors (WDNT, carcinoid tumors) are uncommon indolent neoplasms. The genetic alterations of these tumors are not well characterized. We used genome-wide high-density single nucleotide polymorphism (SNP) array analysis to detect copy number alterations in 29 WDNTs, including seven lung, seven nonileal gastrointestinal, and 15 ileal tumors, and compared with allelic imbalances in 15 pancreatic endocrine tumors (PETs). Most frequent allelic imbalances in WDNTs were losses of chromosome 18 in 10 tumors (34%), chromosome 21 or 21q in six (21%), chromosome 13 or 13q in five (17%) and chromosome 16 or 16q in four (14%) tumors, and amplification of chromosome 20 or 20p in seven (24%) tumors. We also found one tumor with loss of heterozygosity of chromosomes 10 and 15 without copy number loss. These allelic imbalances were associated with primary site of tumor: loss of chromosome 18 was present exclusively in ileal WDNTs (P = 0.001), and loss of chromosome 21 or 21q was more frequent in nonileal gastrointestinal WDNTs (P = 0.02). The tumors with loss of chromosome 21 were larger compared to tumors without loss (P = 0.03). Chromosomal aberrations were less common in WDNTs from lung and gastrointestinal tract compared to PETs (P = 0.001). Our study shows that genome-wide allelotyping using SNP array is a powerful new tool for the analysis of allelic imbalances in WDNTs, and some of these alterations are tumor site-dependent and are different than in PETs. 相似文献
90.
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with autoantibodies as a near universal feature of the disease. Earlier investigations from our laboratory revealed increased oxidative damage in SLE patients. Therefore, we hypothesized that oxidative by-products, such as hydroxyl radical (*OH), could lead to neoantigens like *OH damaged human serum albumin (HSA), which could in turn initiate autoimmunity in SLE. In the present study, the binding characteristics of SLE autoantibodies with native and *OH damaged HSA were assessed. SLE patients (n = 74) were examined by direct binding ELISA and the results were compared with healthy age- and sex-matched controls (n = 44). High degree of specific binding by 52.7% of patients sera towards *OH damaged HSA, in comparison to its native analogue (p < 0.05) was observed. Normal human sera showed negligible binding with either antigen. Competitive ELISA and gel retardation assays reiterate the direct binding results. The increase in total serum protein carbonyl levels in the SLE patients was largely due to an increase in oxidized albumin. HSA of SLE patients (SLE-HSA) and normal subjects (normal-HSA) were purified. Spectroscopic analysis confirmed that the SLE-HSA samples contained higher levels of carbonyls than normal-HSA (p < 0.01). SLE-HSA was conformationally altered, with more exposure of its hydrophobic regions. Collectively, the oxidation of plasma proteins, especially HSA, might enhance oxidative stress in SLE patients. 相似文献