全文获取类型
收费全文 | 21873篇 |
免费 | 1052篇 |
国内免费 | 343篇 |
专业分类
耳鼻咽喉 | 290篇 |
儿科学 | 539篇 |
妇产科学 | 318篇 |
基础医学 | 938篇 |
口腔科学 | 1151篇 |
临床医学 | 3503篇 |
内科学 | 1298篇 |
皮肤病学 | 104篇 |
神经病学 | 1637篇 |
特种医学 | 1730篇 |
外国民族医学 | 1篇 |
外科学 | 5267篇 |
综合类 | 2681篇 |
一般理论 | 1篇 |
预防医学 | 1137篇 |
眼科学 | 797篇 |
药学 | 1213篇 |
37篇 | |
中国医学 | 429篇 |
肿瘤学 | 197篇 |
出版年
2024年 | 56篇 |
2023年 | 407篇 |
2022年 | 573篇 |
2021年 | 859篇 |
2020年 | 800篇 |
2019年 | 734篇 |
2018年 | 704篇 |
2017年 | 744篇 |
2016年 | 677篇 |
2015年 | 692篇 |
2014年 | 1456篇 |
2013年 | 1689篇 |
2012年 | 1162篇 |
2011年 | 1364篇 |
2010年 | 1069篇 |
2009年 | 1125篇 |
2008年 | 1100篇 |
2007年 | 1073篇 |
2006年 | 971篇 |
2005年 | 886篇 |
2004年 | 727篇 |
2003年 | 581篇 |
2002年 | 501篇 |
2001年 | 422篇 |
2000年 | 329篇 |
1999年 | 304篇 |
1998年 | 263篇 |
1997年 | 237篇 |
1996年 | 208篇 |
1995年 | 186篇 |
1994年 | 149篇 |
1993年 | 113篇 |
1992年 | 116篇 |
1991年 | 101篇 |
1990年 | 90篇 |
1989年 | 77篇 |
1988年 | 59篇 |
1987年 | 59篇 |
1986年 | 61篇 |
1985年 | 102篇 |
1984年 | 79篇 |
1983年 | 48篇 |
1982年 | 75篇 |
1981年 | 63篇 |
1980年 | 54篇 |
1979年 | 29篇 |
1978年 | 25篇 |
1977年 | 21篇 |
1976年 | 16篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Abstract – The dental records made on presentation of 1367 consecutive patients (731 females and 636 males) for orthodontic treatment at a private orthodontic practice between 1998 and 2002 were examined for data relating to trauma to the permanent incisors. The results showed that 10.3% of these patients had suffered from dental trauma before the onset of orthodontic treatment. The highest prevalence of dental trauma was determined in the 11–15 years age group, corresponding to the dental developmental stage of the late mixed dentition. The most frequently affected teeth were the maxillary central incisors (79.6%), and the most common types of trauma were fracture of enamel–dentin without pulpal involvement (42.7%) and fracture of enamel (33.8%). Compared to patients with normal overjet and adequate lip coverage, the frequency of dental trauma was significantly higher in patients with increased overjet and adequate lip coverage ( P = 0.028) or with increased overjet and inadequate lip coverage ( P = 0.003). The results of the present study indicate that a significant percentage of candidates for orthodontic treatment, and especially those with increased overjet and inadequate lip coverage, suffer trauma to their permanent incisors before the onset of orthodontic treatment. It might also be concluded that preventive orthodontic treatment of such patients should be initiated and completed before the age of 11, i.e. in the early to middle mixed dentition. 相似文献
13.
David G. Wilder 《American journal of industrial medicine》1993,23(4):577-588
This work is a review of the mechanical factors related to low back pain production in a vibration environment. The sitting posture is an extreme orientation for the lumbar intervertebral disc that 1) increases its internal pressure, 2) increases its anteroposterior shear flexibility, while: 3) decreasing its resistance to buckling instability and 4) stressing the posterior region of the disc. Vibration is an additional mechanical stressor. Several studies suggest that the following preventive measures be taken to reduce the risk of low back pain due to driving: 1) minimize the vibration reaching the driver, 2) avoid lifting or bending immediately following driving, and 3) walk around for a few minutes following driving. © 1993 Wiley-Liss, Inc. 相似文献
14.
15.
The purpose of the present study was to determine the reliability of several selected signs of trauma from occlusion and their relations with severity of periodontitis. 32 moderate to advanced chronic periodontitis patients participated in the study. All teeth present were evaluated for various abnormal occlusal contacts, signs of trauma from occlusion, and the severity of periodontitis. Standardized periapical radiographs were also taken for each tooth. The results demonstrated that: (1) no significant difference occurred in probing pocket depth (PD), clinical attachment loss (AL), or percentage of alveolar bone height (BH) between teeth with and without various abnormal occlusal contacts, i.e., premature contacts in centric relation occlusion, non-working contacts in lateral excursions, premature contacts of anterior teeth or posterior protrusive tooth contacts; (2) teeth with either significant mobility, functional mobility, or radiographically widened periodontal ligament space (PDLS) had deeper PD, more AL and lower BH than teeth without these signs, while teeth with pronounced wear or radiographically thickened lamina dura had less AL than teeth without these findings; (3) 2 combined indices, i.e., the trauma from occlusion index (TOI) and the adaptability index (AI), were proposed for the identification of occlusal trauma and the response of periodontium to excessive biting forces in heavy function, respectively; TOI-positive teeth exhibit deeper PD, more AL and less osseous support than TOI-negative teeth; however, AI-positive teeth had less AL and more osseous support than AI-negative teeth; (4) with identical attachment level, TOI-positive teeth had less osseous support than TOI-negative teeth while the magnitude of difference became greater with an increase of attachment loss. 相似文献
16.
V. Wewer C. Strandberg A. Pærregaard P. A. Krasilnikoff 《European journal of pediatrics》1997,156(10):787-788
We report on our experience with routine abdominal ultrasonography in 120 children (aged 3–15 years) with recurrent abdominal
pain, in order to determine the diagnostic value of this investigation. Eight children (7%) revealed sonographic abnormalities:
gallbladder stone (n = 2), splenomegaly (n = 1) and urogenital abnormalities (n = 5). The recurrent abdominal pain could be explained by these findings in only two (may be three) cases.
Conclusion The diagnostic value of abdominal ultra‐sonography in unselected children with recurrent abdominal pain is low. However,
the direct visualization of the abdominal structures as being normal may be helpful to the parents and the child in their
understanding and acceptance of the benign nature of recurrent abdominal pain.
Received: 19 March 1996 / Accepted: 29 January 1997 相似文献
17.
The experience of Advanced Trauma Life Support training received by three anaesthetists is discussed with particular reference to the teaching of airway management, the grade of staff who should attend the present courses and the relevance to the British hospital system. We conclude that these courses are useful but limited by their inflexibility and failure to recognise the difference in skill mix in the British setting. 相似文献
18.
U. Lehmann G. Regel B. Ellendorf E. Rickels M. Lorenz H. Becker H. Tscherne 《Der Unfallchirurg》1997,100(9):705-710
Summary
A total of 208 multiple trauma patients with head injury (HI) were investigated who had been treated in the period from 1990
to 1995. The average age was 35.2 ± 17.7 years; the injury severity according to ISS was 30.2 ± 8.6 points; 20.5 % died as
a result of the HI; the mortality of all patients was 26.5 %. The Glasgow Coma Scale (GCS) was determined at an average of
22 min after trauma (8.0 ± 4.3 points) at the scene of accident. The patients were classified according to GCS into minor
HI (group 1: 14–15 points), moderate HI (group 2: 9–13 points) and severe HI (group 3: 3–8 points). Patient outcome was assessed
by the Glasgow Outcome Scale (GOS) and was classified as good (GOS 4 and 5) and poor (GOS 1, 2 and 3) outcome. At the latest,
2 h after trauma, a CT scan of the head (CCT) was done. The HI groups are compared regarding frequency of types of injury.
In all HI groups the fractures of the bony face occurred at the same frequency (36.0–38.9 %). The frequency of calotte fractures
(Kal-Fx) increased from group 1 (8.0 %) to 2 (19.2 %) and 3 (25.6 %); fractures of the skull base significantly differed between
group 1 (16.0 %), 2 (7.8 %) and 3 (33.4 %). Epidural hemorrhage (EDB) appeared only in group 2 (7.8 %) and 3 (6.7); subdural
hemorrhage was found in group 1 (2.7 %), 2 (7.8 %) and 3 (10.0 %). Subarachnoid hemorrhage (SAB) was significantly more frequently
seen, dependent on HI severity, in group 3 (26.7 %) compared to group 2 (11.7 %) and 1 (8.0 %). Intracerebral contusion (ICK)
significantly increased from group 1 (12.0 %) to 2 (27.3) and 3 (45.6 %). Brain swelling (BS) also significantly increased
from group 1 (8.0 %) to 2 (19.5 %) and 3 (49.0 %) and lesions of ventricles (VL) from group 1 (2.7 %) to 2 (11.7 %) and 3
(20.0 %). Midline shift (13.4 %) and signs of herniation (4.5 %) only occurred in group 3. The analysis of correlation/regression
and receiver operating characteristics was able to predict 79 % of patients' outcome accurately using GCS (r 0.54; P < 0.0001) alone, using CCT (r 0.65; P < 0.0001) 87 % were correctly predicted with significant variables Cal-Fx, EDB, SAB and BS. CCT with GCS (r 0.74; P < 0.0001) were able to predict 88 % accurately with significant variables Cal-Fx, EDB, BS and GCS. The combination of CCT
with GCS, age and ISS (r 0.78; P < 0.0001) was able to predict only 87 % correctly, although the r value was the highest; significant variables were Kal-Fx, EDB, BS, VL, GCS, age and ISS.
相似文献
19.
Lutz Claes Nikola Maurer-Klein Thomas Henke Heinz Gerngross Mark Melnyk Peter Augat 《Journal of orthopaedic research》2006,24(6):1178-1185
The aim of this study was to investigate the effect of a moderate soft tissue trauma to the course of fracture healing in a standardized animal model. Thirty-eight Wistar rats were randomly divided into a fracture group (F, n = 19) and a group with a fracture and a soft tissue trauma (F + STT, n = 19). The fracture and the soft tissue trauma were created using an impact device with a standardized energy. All fractures were stabilized by two Kirschner wires. Three rats were measured for blood flow and sacrificed at days 1, 3, 7, and 14, and seven rats at day 28, from both groups. A three-point bending test was performed on the healed tibia after 28 days. During the first 24 h there was a reduction in blood flow, which was more pronounced in the F + STT group than in the F group. From histological sections, the shape of the callus formation, as well as the tissue distribution of newly formed bone, fibrous cartilage and fibrous connective tissue were determined. Distinctly more periosteal new bone formed and a larger callus formed at days 3 and 7 in group F compared to group F + STT. However, by days 14 and 28, the ossification and overall callus size no longer showed differences between the two groups. A fast recovery of blood flow and callus formation took place in the F + STT group, which led to similar histological and biomechanical results in fracture healing observed after 28 days between the two groups. 相似文献
20.
A case of unilateral superficial testicular dislocation following blunt scrotal trauma is described, including CT findings. 相似文献