全文获取类型
收费全文 | 2705篇 |
免费 | 147篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 58篇 |
妇产科学 | 51篇 |
基础医学 | 399篇 |
口腔科学 | 34篇 |
临床医学 | 195篇 |
内科学 | 602篇 |
皮肤病学 | 63篇 |
神经病学 | 266篇 |
特种医学 | 142篇 |
外科学 | 388篇 |
综合类 | 11篇 |
预防医学 | 199篇 |
眼科学 | 42篇 |
药学 | 246篇 |
中国医学 | 7篇 |
肿瘤学 | 124篇 |
出版年
2022年 | 28篇 |
2021年 | 32篇 |
2020年 | 20篇 |
2019年 | 30篇 |
2018年 | 40篇 |
2017年 | 31篇 |
2016年 | 46篇 |
2015年 | 57篇 |
2014年 | 69篇 |
2013年 | 72篇 |
2012年 | 111篇 |
2011年 | 132篇 |
2010年 | 84篇 |
2009年 | 68篇 |
2008年 | 108篇 |
2007年 | 111篇 |
2006年 | 112篇 |
2005年 | 113篇 |
2004年 | 104篇 |
2003年 | 120篇 |
2002年 | 109篇 |
2001年 | 115篇 |
2000年 | 110篇 |
1999年 | 78篇 |
1998年 | 22篇 |
1997年 | 22篇 |
1992年 | 46篇 |
1991年 | 33篇 |
1990年 | 48篇 |
1989年 | 45篇 |
1988年 | 52篇 |
1987年 | 55篇 |
1986年 | 49篇 |
1985年 | 41篇 |
1984年 | 19篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1980年 | 13篇 |
1979年 | 35篇 |
1978年 | 33篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 22篇 |
1974年 | 17篇 |
1973年 | 21篇 |
1972年 | 19篇 |
1971年 | 21篇 |
1970年 | 14篇 |
1969年 | 14篇 |
1968年 | 15篇 |
排序方式: 共有2859条查询结果,搜索用时 15 毫秒
101.
102.
Jilly Naaijen Marcel P. Zwiers Natalie J. Forde Steven CR Williams Sarah Durston Daniel Brandeis Jeffrey C. Glennon Barbara Franke David J. Lythgoe Jan K. Buitelaar 《European neuropsychopharmacology》2018,28(1):118-129
Autism spectrum disorders (ASD) and obsessive compulsive disorder (OCD) are often comorbid and are associated with changes in striatal volumes and N-Acetylaspartate (NAA) and glutamate levels. Here, we investigated the relation between dorsal striatal volume and NAA and glutamate levels. We additionally compared striatal volume and shape between ASD, OCD and controls. T1-weighted magnetic resonance (MR) images, proton spectra (1H-MRS) in the left striatum, and phenotypic information were collected from 54 children with ASD, 32 with OCD, and 56 controls (aged 8–13 years) in a four-site study. Dorsal striatal volume and shape were determined using the FMRIB integrated registration and segmentation tool (FIRST). Spectra were processed with Linear Combination Model. The relationship of left striatal volume with NAA and glutamate was investigated, and group comparisons were performed for NAA levels and for bilateral striatal volume and shape. NAA levels were lower in subjects with ASD compared with controls (t=2.86, p=0.005) and were associated with striatal volume (β=0.37, t=2.78, p=0.008). Glutamate levels were also associated with volume in the ASD group (β=0.38, t=2.46, p=0.018). No group differences were found for striatal volume or shape, but a post-hoc diagnosis-by-hemisphere interaction (F(2,129)=3.86, p=0.024) revealed greater asymmetry (right>left) in striatal volume for the disorder-groups compared with controls. Our findings show involvement of NAA and glutamate in striatal volume in ASD and suggest greater asymmetry in paediatric ASD and OCD compared with controls, pointing to overlapping subcortical abnormalities. The lower NAA in ASD reflects reduced neuronal integrity or impaired neuronal functioning. 相似文献
103.
Francesca Waddington Catharina Hartman Yvette de Bruijn Martijn Lappenschaar Anoek Oerlemans Jan Buitelaar Barbara Franke Nanda Rommelse 《European neuropsychopharmacology》2018,28(9):994-1005
Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are frequently comorbid disorders. Emotion recognition problems are considered an important familial deficit in ASD, but this is unknown in ADHD. Very few studies have directly compared emotion recognition performance of youth with ASD and/or ADHD and of their unaffected siblings across age to quantify the contribution of emotion recognition problems to the ADHD phenotype. We therefore devised a study of 64 ASD+ADHD participants, 89 ASD-only participants, 111 ADHD-only participants, 122 unaffected ASD(+ADHD) siblings, 69 unaffected ADHD-only siblings and 220 controls aged 7–18 years, who had completed two tasks assessing auditory and visual emotion recognition. Factor analysis was used to detect underlying dimensions of emotion recognition capacity. Linear mixed models were used to compare performance across groups and to assess age effects. The factor-analysis revealed four factors separating speed and accuracy regarding visual and auditory emotion recognition. ASD+ADHD, ASD-only, and ADHD-only participants all performed worse than controls. ASD+ADHD, ASD-only, and ADHD-only participants did not differ in the severity of their emotion recognition problems. Both unaffected sibling groups performed intermediate between patients and controls. For ASD+ADHD and ADHD-only participants, group differences were more marked in adolescence than childhood, whereas in ASD participants this was not observed. We conclude that emotion recognition problems are a familial deficit in ADHD to a similar extent as in ASD. Emotion recognition problems specifically - and social cognition problems more generally - should be assessed in clinical practice for ADHD. 相似文献
104.
Friedrich Christian Franke Adrian Damek Jonas Steglich Lars Kurch Dirk Hasenclever Thomas W Georgi Walther Alexander Wohlgemuth Christine Mauz-Körholz Dieter Körholz Regine Kluge Judith Landman-Parker William Hamish Wallace Alexander Fosså Dirk Vordermark Jonas Karlen Ana Fernández-Teijeiro Michaela Cepelova Tomasz Klekawka Andishe Attarbaschi Francesco Ceppi Andrea Hraskova Anne Uyttebroeck Auke Beishuizen Karin Dieckmann Thierry Leblanc Martin Moellers Boris Buerke Dietrich Stoevesandt 《Pediatric blood & cancer》2023,70(8):e30421
Background
Rebound thymic hyperplasia (RTH) is a common phenomenon caused by stress factors such as chemotherapy (CTX) or radiotherapy, with an incidence between 44% and 67.7% in pediatric lymphoma. Misinterpretation of RTH and thymic lymphoma relapse (LR) may lead to unnecessary diagnostic procedures including invasive biopsies or treatment intensification. The aim of this study was to identify parameters that differentiate between RTH and thymic LR in the anterior mediastinum.Methods
After completion of CTX, we analyzed computed tomographies (CTs) and magnetic resonance images (MRIs) of 291 patients with classical Hodgkin lymphoma (CHL) and adequate imaging available from the European Network for Pediatric Hodgkin lymphoma C1 trial. In all patients with biopsy-proven LR, an additional fluorodeoxyglucose (FDG)-positron emission tomography (PET)-CT was assessed. Structure and morphologic configuration in addition to calcifications and presence of multiple masses in the thymic region and signs of extrathymic LR were evaluated.Results
After CTX, a significant volume increase of new or growing masses in the thymic space occurred in 133 of 291 patients. Without biopsy, only 98 patients could be identified as RTH or LR. No single finding related to thymic regrowth allowed differentiation between RTH and LR. However, the vast majority of cases with thymic LR presented with additional increasing tumor masses (33/34). All RTH patients (64/64) presented with isolated thymic growth.Conclusion
Isolated thymic LR is very uncommon. CHL relapse should be suspected when increasing tumor masses are present in distant sites outside of the thymic area. Conversely, if regrowth of lymphoma in other sites can be excluded, isolated thymic mass after CTX likely represents RTH. 相似文献105.
Dan Bieler Thomas Paffrath Annelie Schmidt Maximilian Vollmecke Rolf Lefering Martin Kull Erwin Kollig Axel Franke Sektion NIS of the German Trauma Society 《中华创伤杂志(英文版)》2020,23(4):224-232
Purpose: The mortality rate for severely injured patients with the injury severity score (ISS) 16 has decreased in Germany. There is robust evidence that mortality is influenced not only by the acute trauma itself but also by physical health, age and sex. The aim of this study was to identify other possible influences on the mortality of severely injured patients.
Methods: In a matched-pair analysis of data from Trauma Register DGU®, non-surviving patients from Germany between 2009 and 2014 with an ISS 16 were compared with surviving matching partners. Matching was performed on the basis of age, sex, physical health, injury pattern, trauma mechanism,
conscious state at the scene of the accident based on the Glasgow coma scale, and the presence of shock on arrival at the emergency room.
Results: We matched two homogeneous groups, each of which consisted of 657 patients (535 male, average age 37 years). There was no significant difference in the vital parameters at the scene of the accident, the length of the pre-hospital phase, the type of transport (ground or air), pre-hospital fluid management and amounts, ISS, initial care level, the length of the emergency room stay, the care received at night or from on-call personnel during the weekend, the use of abdominal sonographic imaging, the type of X-ray imaging used, and the percentage of patients who developed sepsis. We found a significant difference in the new injury severity score, the frequency of multi-organ failure, hemoglobine at admission, base excess and international normalized ratio in the emergency room, the type of accident (fall or road traffic accident), the pre-hospital intubation rate, reanimation, in-hospital fluid management, the frequency of transfusion, tomography (whole-body computed tomography), and the necessity of emergency intervention.
Conclusion: Previously postulated factors such as the level of care and the length of the emergency room stay did not appear to have a significant influence in this study. Further studies should be conducted to analyse the identified factors with a view to optimising the treatment of severely injured patients. Our study shows that there are significant factors that can predict or influence the mortality of severely
injured patients. 相似文献
106.
Dr. D. Bieler A.F. Franke S. Hentsch T. Paffrath A. Willms R. Lefering E.W. Kollig TraumaRegister DGU 《Der Unfallchirurg》2014,117(11):995-1004
Background
The management of gunshot wounds is a rare challenge for trauma surgeons in Germany and Central Europe as a result of the low incidence of this type of trauma. Penetrating injuries occur with an incidence of 5% in Germany. They are caused by gunshots or more commonly by knives or other objects, for example during accidents. Since even the number of patients who are treated at level 1 trauma centres is limited by the low incidence, the objective of this study was to assess the epidemiology and outcome of gunshot and stab wounds in Germany.Material and methods
Since 2009, the trauma registry of the German Trauma Society (TraumaRegister DGU®) has been used to assess not only whether a trauma was penetrating but also whether it was caused by a gunshot or a stabbing. On the basis of this registry, we identified relevant cases and defined the observation period. Data were taken from the standard documentation forms that participating German hospitals completed between 2009 and 2011. We did not specify exclusion criteria in order to obtain as comprehensive a picture as possible of the trauma entities investigated in this study. As a result of the high incidence of gunshot wounds to the head and the implications of this type of injury for the entire group, a subgroup of patients without head injuries was analysed.Results
From 2009 to 2011, there were 305 patients with gunshot wounds and 871 patients with stab wounds. The high proportion of suicide-related gunshot wounds to the head resulted in a cumulative mortality rate of 39.7%. Stab wounds were associated with a lower mortality rate (6.2%). Every fourth patient with a gunshot or stab wound presented with haemorrhagic shock, which was considerably more frequently seen during the prehospital phase than during the inhospital phase of patient management. Of the patients with gunshot wounds, 26.9% required transfusions. This percentage was three times higher than that for patients with blunt trauma.Conclusion
In Germany, gunshot and stab wounds have a low incidence and are mostly caused by violent crime or attempted suicide. Depending on the site of injury, they have a high mortality and are often associated with major haemorrhage. As a result of the low incidence of these types of trauma, further data and analyses are required which can provide the basis for an evaluation of the long-term quality of the management of patients with stab or gunshot wounds. 相似文献107.
108.
Stefan Polenz Willy Kunz Benjamin Braun Andrea Franke Elena Lpez Frank Brückner Christoph Leyens 《Materials》2021,14(12)
Ceramic matrix composites (CMCs) are refractory ceramic materials with damage-tolerant behavior. Coming from the space industry, this class of materials is increasingly being used in other applications, such as automotive construction for high-performance brake discs, furnace technology, heat coatings for pipe systems and landing flaps on reusable rocket sections. In order to produce CMC faster and more cost-efficiently for the increasing demand, a new additive manufacturing process is being tested, which in the future should also be able to realize material joints and higher component wall thicknesses than conventional processes. The main features of the process are as follows. A ceramic fiber bundle is de-sized and infiltrated with ceramic suspension. The bundle infiltrated with matrix material is dried and then applied to a body form. During application, the matrix material is melted by laser radiation without damaging the fiber material. For the initial validation of the material system, samples are pressed and analyzed for their absorption properties using integrating sphere measurement. With the results, a suitable processing laser is selected, and initial melting tests of the matrix system are carried out. After the first validation of the process, a test system is set up, and the first test specimens are produced to determine the material parameters. 相似文献
109.
Intermediate-size filaments in a germ cell: Expression of cytokeratins in oocytes and eggs of the frog Xenopus. 总被引:10,自引:4,他引:10
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J K Franz L Gall M A Williams B Picheral W W Franke 《Proceedings of the National Academy of Sciences of the United States of America》1983,80(20):6254-6258
Vitellogenic oocytes and eggs of the frog Xenopus laevis contain intermediate-size filaments that are resistant to extractions in high-salt buffers and Triton X-100 and are specifically stained with antibodies to cytokeratins. Gel electrophoresis of cytoskeletal proteins from Xenopus oocytes shows a specific enrichment of three polypeptides designated components 1 [Mr, 56,000; IEP (pI obtained by two-dimensional gel electrophoresis in the presence of 9.5 M urea), ca. 5.9], 2 (Mr, 46,000; IEP, 5.38), and 3 (Mr, 42,000; IEP, ca. 5.3). The same three cytoskeletal polypeptides are found in eggs and early embryos, in intestinal mucosa of adult frogs, and in cultured kidney epithelial cells. They are different from amphibian vimentin and desmin and from the keratins present in the epidermis of adult frogs. Peptide mapping and immunoblotting experiments indicate that Xenopus cytokeratin component 1 is related to cytokeratin A of higher vertebrates but is different from the two smaller cytoskeletal polypeptides 2 and 3. Incorporation of [35 S]methionine shows that all three polypeptides are synthesized in both oocytes and embryos. Our observations show that maternal storage is not only restricted to proteins serving basic cellular functions but also can extend to proteins related to a specific form of cell differentiation (i.e., epithelial formation) in the early embryo. The data suggest that mechanisms of epithelial differentiation in Xenopus embryogenesis are different from those of early mammalian embryos in which no such intermediate-size-filament storage pool has been detected. 相似文献
110.
AIMS: We sought to evaluate whether left ventricular (LV) mass (M) determined by M-mode echocardiography is overestimated compared with LVM calculated by three-dimensional (3D) echocardiography (E) in patients with normal LV shape. METHODS AND RESULTS: A total of 112 studies in 56 patients (60+/-13 years) with hypertension (n=25) or aortic stenosis (n=31) and 30 control subjects (57+/-14 years) evaluated for cardiac sources of embolism were analyzed. LVM by M-mode and 3DE was highly correlated (r=0.85; p<0.001). However, there were broad limits of agreement (-58 to 110 g) demonstrating large variability between the methods. M-mode overestimated 3DE LVM by a mean of 15+/-24% (p<0.001) with overestimation in controls and the different patient groups. Variability was unrelated to increasing quartiles of LVM values. Using technique-specific partition values for normal LVM, the agreement between M-mode and 3DE for the detection of LV hypertrophy was 83% (Kappa=0.59; p<0.001). CONCLUSION: Although M-mode and 3DE correlate well for the calculation of LVM, there is a systematic difference between the two techniques leading to overestimation of LVM by the 1D technique. Thus, previously published cutoff values for normal LVM derived from M-mode may not apply for 3DE. However, the use of technique-specific partition values allows stratification of patients for the presence of LV hypertrophy with reasonable agreement. 相似文献