全文获取类型
收费全文 | 386篇 |
免费 | 18篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 10篇 |
妇产科学 | 4篇 |
基础医学 | 53篇 |
口腔科学 | 12篇 |
临床医学 | 21篇 |
内科学 | 86篇 |
皮肤病学 | 21篇 |
神经病学 | 11篇 |
特种医学 | 68篇 |
外科学 | 36篇 |
综合类 | 10篇 |
预防医学 | 5篇 |
眼科学 | 9篇 |
药学 | 45篇 |
中国医学 | 3篇 |
肿瘤学 | 22篇 |
出版年
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 19篇 |
2009年 | 21篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 22篇 |
1997年 | 16篇 |
1996年 | 20篇 |
1995年 | 16篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有418条查询结果,搜索用时 15 毫秒
71.
Hadlock FP; Harrist RB; Fearneyhough TC; Deter RL; Park SK; Rossavik IK 《Radiology》1985,154(2):503-505
The femur length/abdominal circumference ratio, expressed as FL/AC X 100, was determined in 156 fetuses and evaluated as a predictor of fetal macrosomia within one week prior to delivery. The normal range (mean +/- 2 SD) in the 105 normal-weight fetuses was 22.0 +/- 2, while the normal range in the 51 macrosomic fetuses was 20.5 +/- 2; these differences were highly significant (P = less than .0001). The predictive power of a positive ratio was 68%, with a sensitivity of 63%. This ratio was particularly useful in the subset (n = 9) of macrosomic fetuses whose mothers were diabetic, correctly identifying 89% of this group. Because it is age independent, this ratio should prove most helpful in identifying fetuses at risk for macrosomia in patients whose dates are not known, since it may become abnormal before the fetal weight falls above the 90th percentile at term (3,900 g). In patients whose dates are known, early fetal macrosomia is best predicted by evaluating the abdominal circumference against normal standards for age. 相似文献
72.
The aim of this study is to investigate and demonstrate the mechanical and corrosive characteristics of the neodymium-containing magnesium alloy MgNd2 (Nd2), which can be used as a resorbable implant material, especially in the field of stenting applications. To determine the mechanical characteristics of Nd2, tensile and compression tests were initially carried out in the hot extruded state. Here a unique elongation ratio (~30%) of the alloy could be observed. Subsequent T5 and T6 heat treatments were arranged to reveal their effect on the alloy's strengths and elongation values. The general degradation behaviour of Nd2 in a 0.9% NaCl solution was investigated by means of polarization curves and hydrogen evolution. In addition to this, by using various in vivo parameters, a corrosion environment was established to determine the alloy's degradation in vitro. Here, the mass loss per day in (MgF(2) and Bioglass)-coated and uncoated states and the corresponding maximum forces resulting from subsequent three-point bending tests revealed slow and steady corrosion behaviour. The cell viability and proliferation tests carried out on L-929 and MSC-P5 cells also showed good results. The mechanical and corrosive characteristics determined, as well as the in vitro test results obtained within the scope of this study, led to the development and successful in vivo testing of an MgF(2)-coated Nd2 mucosa stent which was introduced as an appropriate resorbable application. 相似文献
73.
Sandipan Chakroborty Mansi Gupta Chitralekha S Devishamani Krunalkumar Patel Chavan Ankit TC Ganesh Babu Rajiv Raman 《Indian journal of ophthalmology》2021,69(11):2999
Diabetic macular edema (DME), being a frequent manifestation of DR, disrupts the retinal symmetry. This event is particularly triggered by vascular endothelial growth factors (VEGF). Intravitreal injections of anti-VEGFs have been the most practiced treatment but an expensive option. A major challenge associated with this treatment is determining an optimal treatment regimen and differentiating patients who do not respond to anti-VEGF. As it has a significant burden for both the patient and the health care providers if the patient is not responding, any clinically acceptable method to predict the treatment outcomes holds huge value in the efficient management of DME. In such situations, artificial intelligence (AI) or machine learning (ML)-based algorithms come useful as they can analyze past clinical details of the patients and help clinicians to predict the patient''s response to an anti-VEGF agent. The work presented here attempts to review the literature that is available from the peer research community to discuss solutions provided by AI/ML methodologies to tackle challenges in DME management. Lastly, a possibility for using two different types of data has been proposed, which is believed to be the key differentiators as compared to the similar and recent contributions from the peer research community. 相似文献
74.
DL Domingo MI Trujillo SE Council MA Merideth LB Gordon T Wu WJ Introne WA Gahl TC Hart 《Oral diseases》2009,15(3):187-195
Objective: Hutchinson-Gilford progeria syndrome (HGPS) is a rare early-onset accelerated senescence syndrome. In HGPS, a recently identified de novo dominant mutation of the lamin A gene ( LMNA ) produces abnormal lamin A, resulting in compromised nuclear membrane integrity. Clinical features include sclerotic skin, cardiovascular and bone abnormalities, and marked growth retardation. Craniofacial features include 'bird-like' facies, alopecia, craniofacial disproportion, and dental crowding. Our prospective study describes dental, oral soft tissue, and craniofacial bone features in HGPS.
Methods: Fifteen patients with confirmed p.G608G LMNA mutation (1–17 years, seven males, eight females) received comprehensive oral evaluations. Anomalies of oral soft tissue, gnathic bones, and dentition were identified.
Results: Radiographic findings included hypodontia ( n = 7), dysmorphic teeth ( n = 5), steep mandibular angles ( n = 11), and thin basal bone ( n = 11). Soft tissue findings included ogival palatal arch ( n = 8), median sagittal palatal fissure ( n = 7), and ankyloglossia ( n = 7). Calculated dental ages (9 months to 11 years 2 months) were significantly lower than chronological ages (1 year 6 months to 17 years 8 months) ( P = 0.002). Eleven children manifested a shorter mandibular body, anterior/posterior cranial base and ramus, but a larger gonial angle, compared to age/gender/race norms.
Conclusion: Novel oral-craniofacial phenotypes and quantification of previously reported features are presented. Our findings expand the HGPS phenotype and provide additional insight into the complex pathogenesis of HGPS. 相似文献
Methods: Fifteen patients with confirmed p.G608G LMNA mutation (1–17 years, seven males, eight females) received comprehensive oral evaluations. Anomalies of oral soft tissue, gnathic bones, and dentition were identified.
Results: Radiographic findings included hypodontia ( n = 7), dysmorphic teeth ( n = 5), steep mandibular angles ( n = 11), and thin basal bone ( n = 11). Soft tissue findings included ogival palatal arch ( n = 8), median sagittal palatal fissure ( n = 7), and ankyloglossia ( n = 7). Calculated dental ages (9 months to 11 years 2 months) were significantly lower than chronological ages (1 year 6 months to 17 years 8 months) ( P = 0.002). Eleven children manifested a shorter mandibular body, anterior/posterior cranial base and ramus, but a larger gonial angle, compared to age/gender/race norms.
Conclusion: Novel oral-craniofacial phenotypes and quantification of previously reported features are presented. Our findings expand the HGPS phenotype and provide additional insight into the complex pathogenesis of HGPS. 相似文献
75.
The present study was undertaken to evaluate the dimensions of the laminas from C2 to L5 by using adult human spine specimens for the objective of providing a set of quantitative data for the laminas from C2 to L5 vertebrae.There exists enormous amount of Anatomic data based on facet and pedicle parameters by different research workers, but it seems that the detailed studies based on measurements of laminar parameters from cervical to lumbar spines are almost nil.Forty spines (920 vertebrae) were considered for the present study. Anatomic evaluation of the laminas'included the laminar height, width, thickness, width angle & slope angle.The greatest laminar height was observed at T11 for males & females ( 22.8 ± 2.1 mm, 23.0 + 1.8mm) respectively. There was a marked change in pattern at L5 where there was a decrease in laminar height from that of preceding lumbar levels.The greatest laminar width was at-L5 for males & females (12.1 ± 2.4mm 11.5 ± 2.1 mm ) respectively. The laminar thickness was maximum at T3 for males and females (5:2 ± 0.7mm & 5.1 ± 0.2mm ) respectively. The maximum width angle was at T9 for males (99.2 ± 9.7mm) & at L4for females (100.6 ± 12.3mm). The-slope angle was maximum at L5 for males and females (113.5 ± 4.8mm & 118.0 ± 1.4mm) respectively.Thus, for the proper, understanding of the weight transmission through the spine and it related hypothesis the Anatomic parameters of the laminas provided by the present study are very important and also they provide an adequate database necessary for the surgical placement of sublaminar instruments in spine related surgeries. 相似文献
76.
Gschwandtner M Purwar R Wittmann M Bäumer W Kietzmann M Werfel T Gutzmer R 《The Journal of investigative dermatology》2008,128(12):2783-2791
Skin inflammation and the migration of cells at the site of the immune response play an important role in allergic skin diseases. It has already been described that matrix metalloproteinase 9 (MMP-9) influences tissue remodeling and facilitates cell migration by proteolytic degradation of basal membrane components. The aim of this study was to investigate MMP-9 expression on human primary keratinocytes (KCs) upon stimulation with histamine, a potent mediator in allergic responses. With ELISA and zymography, we could show that histamine induced dose-dependent upregulation of MMP-9 in cultured KCs and in punch biopsies of human skin. The histamine H(1) receptor (H(1)R) agonist beta-histine-but not agonists for H(2)R, H(3)R, and H(4)R-induced MMP-9, whereas the H(1)R antagonist clemastine blocked the effect in a dose-dependent manner. Immunohistological staining showed that histamine-induced MMP-9 led to destruction of type IV collagen at the basement membrane in healthy skin. In a coculture system of KCs and T cells, migration of T cells through an artificial basement membrane was increased after histamine stimulation of KCs. Our findings demonstrate enhanced MMP-9 production and cell migration after histamine stimulation and may represent a new mechanism by which KCs contribute to the pathology of skin diseases. 相似文献
77.
Purwar R Bäumer W Niebuhr M Tschernig T Kietzmann M Werfel T 《Experimental dermatology》2011,20(9):709-714
Keratinocytes synthesize complement component 3 (C3) constitutively, and increased expression of C3 has been described during skin inflammation. In this study, we investigated the role of C3 in T cell-mediated allergic contact dermatitis, which is a clinical manifestation of contact sensitivity (CS). C3-deficient mice (C3KO) showed substantial higher CS responses to haptens, inducing a Th1 cytokine-mediated skin inflammation (2,4-dinitrofluorobenzene and dinitrochlorobenzene), and to haptens known to induce a Th2-polarized inflammatory response (fluoro-isothiocynate and toluene-2,4-diisocyanate) as compared to their wild-type (WT) controls. There was a higher influx of GR-1(+) , CD4(+) , and CD8(+) cells into the skin of hapten-treated C3KO mice compared with WT mice. Activated splenocytes from C3KO mice immunized with DNCB secreted higher amounts of IFN-γ compared with WT controls but not of Th2 (IL-4, IL-5, and IL-10) cytokines or IL-17. A higher secretion of IL-12 from splenocytes of C3KO mice as compared with WT mice was observed after TLR-4 ligand (LPS) or TLR-2 ligand (peptidoglycan) stimulation. Thus, an increased expression of IL-12 and of IFN-γ may be responsible for the increased hapten-induced inflammation in C3 deficiency. Finally, we demonstrated that C3KO mice developed oral tolerance to haptens to a lower degree than WT mice. Our findings provide a new insight into a novel anti-inflammatory role of C3 in skin inflammation. 相似文献
78.
To date, the relative contribution of the different levels of the visual hierarchy during perceptual decisions remains unclear. Typical models of visual processing, with the reverse hierarchy theory (RHT) as a prominent example, strongly emphasize the role of higher levels and interpret lower levels as sequence of simple feature detectors. Here, we investigate this issue based on two analyses. Using a novel combination of perceptual learning based on two classes of parametric faces and a subsequent odd-one-out paradigm, we first test a vital prediction of RHT: high-level pop-out. With this experimental approach, we overcome the low-level confounds of previous studies while still introducing distinct high-level representations. Contrary to previous findings, our analyses show that there is no high-level pop-out, despite very early, near-perfect classification accuracy and extensive training of our subjects. Second, we explore the underlying form of category representation during subsequent stages of perceptual training. This is accomplished by including class-external and class-internal target-distractor combinations. Whereas the subjects' responses during the first sessions are best explained instance-based and dependent on low-level metric differences, later patterns exhibit the inclusion of high-level, class-based information that is independent of target-stimulus similarity. Finally, we show that the utilized level of information is highly task-dependent. 相似文献
79.
80.
Stephen LChan Philip JJohnson Frankie Mo Sarah Berhane Mabel Teng Anthony WH Chan Ming CPoon Paul BS Lai Simon Yu Anthony TC Chan Winnie Yeo 《癌症》2014,(10):481-491
The outcome of hepatocellular carcinoma (HCC) patients significantly differs between western and eastern population centers. Our group previously developed and validated the Chinese University Prognostic Index (CUPI) for the prognostication of HCC among the Asian HCC patient population. In the current study, we aimed to validate the CUPI using an international cohort of patients with HCC and to compare the CUPI to two widely used staging systems, the Barcelona Clinic Liver Cancer (BCLC) classification and the Cancer of the Liver Italian Program (CLIP). To accomplish this goal, two cohorts of patients were enrolled in the United Kingdom (UK; n = 567; 2006-2011) and Hong Kong (HK; n = 517; 2007-2012). The baseline clinical data were recorded. The performances of the CUPI, BCLC, and CLIP were compared in terms of a concordance index (C-index) and were evaluated in subgroups of patients according to treatment intent. The results revealed that the median follow-up durations of the UK and HK cohorts were 27.9 and 29.8 months, respectively. The median overall survival of the UK and HK cohorts were 22.9 and 8.6 months, respectively. The CUPI stratified the patients in both cohorts into three risk subgroups corresponding to distinct outcomes. The median overall survival of the CUPI low-, intermediate-, and high-risk subgroups were 3.15, 1.24, and 0.29 years, respectively, in the UK cohort and were 2.07, 0.32, and 0.10 years, respectively, in the HK cohort. For the patients who underwent curative treatment, the prognostic performance did not differ between the three staging systems, and all were suboptimal. For those who underwent palliative treatment, the CUPI displayed the highest C-index, indicating that this staging system was the most informative for both cohorts. In conclusion, the CUPI is applicable to both western and eastern HCC patient populations. The performances of the three staging systems differed according to treatment intent, and the CUPI was demonstrated to be optimal for those 相似文献