全文获取类型
收费全文 | 937498篇 |
免费 | 65049篇 |
国内免费 | 3254篇 |
专业分类
耳鼻咽喉 | 12789篇 |
儿科学 | 29612篇 |
妇产科学 | 27120篇 |
基础医学 | 130782篇 |
口腔科学 | 25383篇 |
临床医学 | 78257篇 |
内科学 | 191878篇 |
皮肤病学 | 19605篇 |
神经病学 | 74754篇 |
特种医学 | 37744篇 |
外国民族医学 | 338篇 |
外科学 | 146981篇 |
综合类 | 21095篇 |
现状与发展 | 1篇 |
一般理论 | 248篇 |
预防医学 | 66693篇 |
眼科学 | 20611篇 |
药学 | 67136篇 |
8篇 | |
中国医学 | 2750篇 |
肿瘤学 | 52016篇 |
出版年
2019年 | 7399篇 |
2018年 | 10166篇 |
2017年 | 8084篇 |
2016年 | 8651篇 |
2015年 | 9984篇 |
2014年 | 13970篇 |
2013年 | 21150篇 |
2012年 | 28189篇 |
2011年 | 29831篇 |
2010年 | 18110篇 |
2009年 | 17191篇 |
2008年 | 28211篇 |
2007年 | 29843篇 |
2006年 | 29833篇 |
2005年 | 29291篇 |
2004年 | 27927篇 |
2003年 | 26831篇 |
2002年 | 26302篇 |
2001年 | 42254篇 |
2000年 | 43438篇 |
1999年 | 37086篇 |
1998年 | 10321篇 |
1997年 | 9406篇 |
1996年 | 9344篇 |
1995年 | 8664篇 |
1994年 | 8268篇 |
1993年 | 7735篇 |
1992年 | 28641篇 |
1991年 | 27366篇 |
1990年 | 26766篇 |
1989年 | 25719篇 |
1988年 | 23867篇 |
1987年 | 23448篇 |
1986年 | 22512篇 |
1985年 | 21357篇 |
1984年 | 15981篇 |
1983年 | 13615篇 |
1982年 | 8167篇 |
1979年 | 14733篇 |
1978年 | 10290篇 |
1977年 | 8703篇 |
1976年 | 8208篇 |
1975年 | 9023篇 |
1974年 | 10790篇 |
1973年 | 10283篇 |
1972年 | 9753篇 |
1971年 | 9004篇 |
1970年 | 8652篇 |
1969年 | 8101篇 |
1968年 | 7738篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Magnetic resonance imaging confirmation of resolution of periodontoid pannus formation following C1/C2 posterior transarticular screw fixation. 总被引:3,自引:0,他引:3
Chronic odontoid fractures are considered unstable spinal lesions. Chronic instability in this region leads to the development of an inflammatory pannus, which can progress resulting in spinal cord compression radiographically and a myelopathy syndrome clinically. In this report we document three cases of reversal of pannus after C1/C2 transarticular screw fixation of an unstable odontoid fracture. Three patients were identified with chronic odontoid fractures and spinal cord compression due to periodontoid pannus formation. All patients presented with a progressive myelopathy syndrome. All patients underwent preoperative and postoperative magnetic resonance imaging (MRI) of the craniovertebral junction. C1/C2 transarticular screw fixation was performed for stabilization of C1/C2. Postoperatively there were no complications. Postoperative MRI at 6 months demonstrated resolution of the ventral pannus. Moreover, all patients exhibited improvement of preoperative neurological deficits. MRI is the imaging technique of choice for diagnosis and follow-up of patients with chronic odontoid fractures and ventral pannus. C1/C2 transarticular screw fixation provides a viable method for spinal stabilization in this region. In addition, stabilization can result in resolution of inflammatory pannus formation secondary to instability of the C1/C2 articulation. 相似文献
152.
The authors report the association of erythroleukemia (FAB M6) and fetal hemoglobin (HbF) level of at least 65% after therapy for ovarian carcinoma. The patient's erythrocytes had many signs of reversion to fetal-like erythropoiesis including: elevated HbF with a fetal G gamma/A gamma (gly/ala) of 3/1, low hemoglobin A2 (HbA2), macrocytosis, and increased i antigen. These data and data from other case reports suggest that elevation of HbF to greater than 25% with reversion to fetal-like erythropoiesis is useful in differentiating erythroleukemia from other preleukemic disorders. 相似文献
153.
P Tugwell L Hart G Kraag A Park C Dok F Bianchi C Goldsmith W W Buchanan 《The Journal of rheumatology》1984,11(4):457-461
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used. 相似文献
154.
155.
In comparative histological and cytological studies on 270 prostatic carcinoma patients highly and moderately differentiated tumors were found to be more frequent histologically than cytologically. An early and reliable sign of response to hormone therapy proved to be reticularization and vacuolization of the nuclear chromatin. Follow-up studies by means of multiple aspiration biopsies with cytologic examinations seem to be more reliable in prognostic terms than examination of the histological tumor structure. 相似文献
156.
K Mahmood M N Chowdhury E A Ayoola I A Mofleh R S Rashed F Z Faleh 《Tropical gastroenterology》1991,12(4):188-191
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture. 相似文献
157.
Spontaneous neuronal hyperactivity in the medial and intralaminar thalamic nuclei of patients with deafferentation pain 总被引:6,自引:0,他引:6
Electrical activity was recorded from single cells in the thalamus of 10 patients with chronic pain associated with deafferentation. Under local anesthesia, these patients underwent either electrode implantation or thalamotomy for treatment of their pain. In eight of the 10 patients, single units were identified as discharging spontaneously in high-frequency, often rhythmic, bursts. The discharges were of two types: short bursts comprised of two to six spikes with a burst frequency of one to four per second; and long trains of 30 to 80 spikes of similar frequency. Reconstruction of electrode trajectories indicated that recordings were made from the region corresponding to the lateral aspect of the mediodorsal thalamic nucleus, the central lateral nucleus, a small part of the central median nucleus, and the parafascicular nucleus. In the eight patients in whom spontaneous neuronal burst activity was exhibited, it was impossible to study activity evoked by natural cutaneous stimulation due to the continuous spontaneous neuronal discharges. Both animal and human studies have suggested that pain related to deafferentation is accompanied by spontaneous hyperactivity in the dorsal horn of the spinal cord and in the ventral posterior thalamic nuclei. The authors present evidence of spontaneous neuronal hyperactivity in the intralaminar thalamic nuclei of patients with pain related to deafferentation. The findings suggest that spontaneous neuronal discharge in patients with pain related to deafferentation is more widespread in the central nervous system than has been previously appreciated. The results have important implications for the surgical treatment of chronic pain. 相似文献
158.
F M Burkle 《Emergency Medicine Clinics of North America》1991,9(1):87-105
Existing triage algorithms consider, for the most part, only the primary casualty with physical trauma. Algorithms fail to appreciate the primary, secondary, or tertiary neuropsychiatric casualty. Research advances on neuropsychiatric casualties must link with the mandates of emergency medical services and disaster management to improve triage sensitivity and specificity. Early recognition and management of neuropsychiatric casualties will diminish the potential for long-term consequences. Expanded triage algorithm supplements are proposed to improve the recognition of those victims at risk. 相似文献
159.
Pregnant rats were injected with a single dose of methylazoxymethanol (MAM, 25 mg/kg) on gestational day 14, 15, 16, 17, 18 or 19 and offspring were tested for their physical development, reflex development and spontaneous activity. MAM treatment did not affect gestational and litter parameters at any of the time of administration studied. Treatment at gestational day 14 (GD14) had the most severe effect on functional neurodevelopment until weaning: righting reflex at surface, chimney test, horizontal wire test resulted altered. Administration at GD15, 16, 18, 19 did not affect the performance in these tests. Offspring treated at GD17 showed a delayed eye opening and an impaired performance in the horizontal wire test. When tested at 50 days of age on the rotarod, all the treated groups performed worse than controls with the exception of GD19 treated offspring. Administration at GD14 and GD15 resulted in increased spontaneous activity of the offspring at 21 days but not at 60 days of age. Different degrees of microencephaly were observed for all treated groups. The results indicate that alterations of physical and behavioral development induced by MAM treatment are dependent on the time of MAM administration, and specific behavioral tests are able to detect different abnormalities and differentiate among treatment groups. Some alterations observed in MAM rats undergo to adaptive changes during maturation of the CNS. 相似文献
160.
Afterpotential characteristics and firing patterns in maturing rat hippocampal CA1 neurones in in vitro slices. 总被引:2,自引:0,他引:2
The postnatal evolution of depolarizing after-potentials (DAPs) and after-hyperpolarizations (AHPs) was studied in rat CA1 hippocampal neurones (5-68 days of age) using in vitro slices. Results were pooled into 4 age groups: P5-9, P10-16, P17-24 and P26-68. In P5-9 cells, DAPs were seen as passive signals, with a time constant similar to the time constant of the membrane. The evolution of the DAP was characterized by a decrease in amplitude, an increase in duration and a change in contour. In P10-16 and P17-24 cells, the DAPs often had a plateau or a hump-like shape which increased the probability of firing and the occurrence of spike doublets. The firing pattern and bursting behaviour of P10-16 CA1 neurones differed from the pattern typical of the adult. P5-9 and P10-16 cells had post-burst AHPs with a smaller amplitude and a more prolonged early phase than at late stages of development. 相似文献