全文获取类型
收费全文 | 53440篇 |
免费 | 3662篇 |
国内免费 | 2273篇 |
专业分类
耳鼻咽喉 | 990篇 |
儿科学 | 1357篇 |
妇产科学 | 236篇 |
基础医学 | 6612篇 |
口腔科学 | 7817篇 |
临床医学 | 4415篇 |
内科学 | 5115篇 |
皮肤病学 | 298篇 |
神经病学 | 1135篇 |
特种医学 | 2453篇 |
外国民族医学 | 20篇 |
外科学 | 13497篇 |
综合类 | 7443篇 |
现状与发展 | 8篇 |
预防医学 | 1408篇 |
眼科学 | 492篇 |
药学 | 2176篇 |
39篇 | |
中国医学 | 1432篇 |
肿瘤学 | 2432篇 |
出版年
2024年 | 424篇 |
2023年 | 1072篇 |
2022年 | 1667篇 |
2021年 | 2109篇 |
2020年 | 2101篇 |
2019年 | 2044篇 |
2018年 | 1846篇 |
2017年 | 1891篇 |
2016年 | 1800篇 |
2015年 | 1971篇 |
2014年 | 3220篇 |
2013年 | 4287篇 |
2012年 | 2614篇 |
2011年 | 3057篇 |
2010年 | 2634篇 |
2009年 | 2461篇 |
2008年 | 2452篇 |
2007年 | 2464篇 |
2006年 | 2263篇 |
2005年 | 2155篇 |
2004年 | 1938篇 |
2003年 | 1704篇 |
2002年 | 1441篇 |
2001年 | 1266篇 |
2000年 | 1022篇 |
1999年 | 923篇 |
1998年 | 782篇 |
1997年 | 747篇 |
1996年 | 685篇 |
1995年 | 506篇 |
1994年 | 519篇 |
1993年 | 360篇 |
1992年 | 380篇 |
1991年 | 313篇 |
1990年 | 254篇 |
1989年 | 254篇 |
1988年 | 193篇 |
1987年 | 156篇 |
1986年 | 158篇 |
1985年 | 181篇 |
1984年 | 133篇 |
1983年 | 124篇 |
1982年 | 147篇 |
1981年 | 107篇 |
1980年 | 104篇 |
1979年 | 101篇 |
1978年 | 105篇 |
1977年 | 69篇 |
1976年 | 68篇 |
1975年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Cranioplasty with autogenous autoclaved calvarial bone flap in the cases of tumoural invasion 总被引:2,自引:0,他引:2
V. Vanaclocha N. Sáiz-Sapena C. Garcia-Casasola E. De Alava 《Acta neurochirurgica》1997,139(10):970-976
Summary When a bone flap is raised in the course of a craniotomy, the ideal is to replace it at the end of the procedure. When it is invaded by tumoural cells, it cannot be replaced due to the risk of tumoural recurrence. In these cases we have autoclaved the bone flap to be able to replace it with no fear of tumoural recurrence.Between October 1989 and October 1995 sixty-two patients required autoclaving of the bone flap in the course of a craniotomy due to tumoural invasion (thirty-five meningiomas, sixteen bone tumours, five metastases, and eight scalp tumours).The infiltrated bone flaps were removed, cleaned, autoclaved for 20 minutes at 134 °C and 1 kg/cm2 and re-implanted.Patients were followed-up for 10 to 58 months (average 41 months). At every follow-up visit skull x-ray studies, clinical examination, and photographs were done. When needed a CT scan was performed to assess the thickness of the bone flap.On follow-up roentgenograms partial resorption was observed in twelve cases (19.3%). CT scan studies showed loss of thickness in another thirty-five cases (56.4%). Meanwhile the external aspect remained unchanged.In six cases (3.2%) biopsies of the bone flaps were taken at a second surgical procedure. They showed newly formed bone partly re-populated by osteocytes but retaining areas of sequestered bone.We conclude that autoclaved bone, if replaced with direct contact with living bone, it is gradually repopulated with osteocytes. Cranial vault autoclaved autologous bone flap is a good alternative when the original bone flap is invaded but not destroyed by tumoural cells. 相似文献
32.
An atypical variant of reflex sympathetic dystrophy (RSD) is presented in a 45 year old female with a vascular malformation
of the right arm and chest wall. The mechanism was thought to be compression of the brachial plexus by the malformation. The
unique scintigraphic features of this presentation of RSD in the ulnar arterial distribution are illustrated. 相似文献
33.
肢体不同延长速度对局部血流量的影响 总被引:1,自引:1,他引:0
本文报告20只兔胫骨以不同速度延长时用末梢微循环测定系统动态连续监测局部血流量变化的结果,发现一次延长>1 mm时,局部肌肉血流量开始急骤下降,恢复延长前血流量所需的时间>8 h。作者认为肢体的血管、肌肉等组织对1 mm/次/d延长速度有相当大的生物适应性。延长速度>1 mm/次/d易造成局部血流量大幅度减少。延长肢肌肉萎缩、肌力减弱可能与血流量减少有关。 相似文献
34.
Dmitriy A. Yablonskiy William R. Reinus Helmut Stark E. Mark Haacke 《Magnetic resonance in medicine》1997,37(2):214-221
In this paper, the authors quantitate the anisotropy of susceptibility effects in an uniaxial trabecular bone model and show its relevance to clinical MR bone mineral density measurements. A physical model is described that quantitates the anisotropic MR behavior of uniaxial trabecular bone. To test the model, a phantom of parallel polyethylene filaments was scanned every 15° between 0° and 90° with respect to the system's main magnetic field (B0). The distal radial metaphysis of a healthy female volunteer was scanned in orthogonal projections. The signal from each phantom image and each radial image was separated in a pixel-wise fashion into R2 and R2′ maps. As predicted, R2′ relaxation showed anisotropic behavior and changed according to sin2 (?), confirming that columnar structures parallel with B0 will cause no MR susceptibility effects. Scans of the distal radius showed that R2′ relaxation was twice as great with the forearm perpendicular to B0 as when it was parallel to it, demonstrating different contributions from struts and columns. For both phantom and radial bone scans, R2 relaxation was isotropic and did not change with object orientation. 相似文献
35.
Twenty-six bone marrow transplant recipients, 14 of whom had evidence of acute graft versus host disease at autopsy, were studied. The pancreas in four of these patients exhibited changes thought to be due to acute graft versus host disease. Pathognomonic findings were in exocrine ducts which showed marked epithelial cellular atypia associated with a mild lymphocytic infiltrate. This was accompanied by ulceration and intraluminal haemorrhage in severe cases. In three of these four cases ductal epithelium showed marked hyperexpression of class I and class II major histocompatibility complex molecules. By contrast islets were not inflamed, showed no evidence of endocrine cell damage and no abnormalities of major histocompatibility complex expression were seen. 相似文献
36.
S. J. Carbognin N. M. Solomon F. E. Yeo S. J. Swanson E. M. Bohen J. M. Koff S. G. Sabnis K. C. Abbott 《American journal of transplantation》2006,6(7):1746-1751
Interferon alpha (IFN-alpha) can be effective therapy for patients with chronic kidney disease who have chronic hepatitis C (HCV). However, acute allograft rejection has been reported in association with IFN-alpha following kidney transplantation, and therefore IFN therapy is recommended prior to, rather than after, kidney transplantation whenever feasible. The special case of repeat allograft recipients who contract HCV after the first transplantation presents special difficulties. This report features the case of a repeat allograft recipient who presented with neutropenic fevers after 5 months of pegylated IFN-alpha therapy, initiated 6 months following the functional loss of his third graft and the reinitiation of hemodialysis (HD). Physical exam, radiographic and laboratory findings led to allograft nephrectomy. The pathologic findings supported a diagnosis of acute-on-chronic rejection. This represents a rare case of IFN-alpha induced rejection following allograft failure and return to HD in a repeat allograft recipient. It also calls attention to the need for a high index of suspicion for the development of allograft rejection, which may require allograft nephrectomy even after allograft 'failure'. 相似文献
37.
Kyung‐Sub Moon Shin Jung Jae‐Hyuk Lee Tae‐Young Jung In‐Young Kim Soo‐Han Kim Sam‐Suk Kang 《Neuropathology》2006,26(2):141-146
We present a case of benign osteoblastoma of the occipital bone. Benign osteoblastoma is an uncommon primary bone tumor, which usually involves the vertebrae and the long bones. This tumor rarely develops in the calvaria, showing a preference for the temporal and frontal bones when it does. To the best of our knowledge, this case is only the eighth reported case of benign osteoblastoma confined to the occipital bone. A 20‐year‐old male presented with a mild tender mass lesion of the occipital area, just below the lambda. Plain X‐ray films and CT scans demonstrated an osteolytic mass surrounded by the sclerotic rim within the diploic space. MRI proved to be effective for the evaluation of the intracranial and intraosseous extensions of the tumor. However, it was very difficult to formulate a differential diagnosis against other osteoblastic tumors, or osteoid osteoma, in view of its radiological appearance. The final diagnosis was obtained by careful consideration of the histopathological characteristics of the tumor combined with its clinical and radiological features. Although generally regarded as benign, a complete resection is preferred over conventional curettage as this can guard against possible recurrence and malignant transformation. 相似文献
38.
In order to determine whether the lateral ganglionic eminence (LGE) of the fetal telencephalon is the primary source of striatal precursors in striatal transplants and tissue cultures, cells derived exclusively from the LGE of fetal rat brains were transplanted into the quinolinic-acid-lesioned striatum of adult rats. After 2–3 months they produced grafts that were almost entirely AChE-positive as well as DARPP-32-, TH-, and calbindin-immunoreactive. The grafts were integrated into the host striatum so that host corticofugal fiber tracts interdigitated with graft tissues similar to the way they penetrate the gray matter of the normal striatum. Fast Blue dye injected into the ipsilateral globus pallidus of LGE grafted produced retrogradely labeled neurons within the grafts, but Fluorogold dye injected into the ipsilateral substantia nigra did not. In a separate experiment using DARPP-32-immunohistochemistry as a striatal marker, fetal (E16) and neonatal (P2) rat brains showed DARPP-32 immunoreactivity in the LGE but not in the adjacent medial ganglionic eminence (MGE). In summary, both fetal LGE cells and LGE grafts express specific striatal markers, and LGE grafts integrate into the host striatum and innervate the major striatal efferent target within the host brain. These data suggest that the LGE is the origin of cells committed to striatal phenotypes in the developing brain. 相似文献
39.
取32只2~3个月的BALB/C小白鼠,随机分为4组,每组8只,第1组为对照组,其余3个组为实验组,实验组小白鼠左腿皮下注射苯0.3ml(15ml/kg体重).注射后分别于24h,48h,72h脱颈处死。观察中毒前、后末梢血象、骨髓细胞、骨髓细胞构成的变化。结果表明,苯中毒时骨髓变化先于末梢血象的变化,骨髓的病变为造血细胞变性、坏死,大量毛细血管扩张、充血,骨髓细胞构成降低,而且骨髓细胞构成中细胞成分降低早于外周血粒细胞减少。 相似文献
40.
Two strains of T. rubrum and one strain of T. mentagrophytes were inoculated into human skin grafted onto BALB/c nude mice by the needle puncture method. Infection was established in 1 of the 10 animals inoculated with fluffy colony type T. rubrum, 2 of the 10 animals inoculated with powdery colony type T. rubrum, and 7 of the 10 animals inoculated with granular colony type T. mentagrophytes, suggesting that the skin grafts are infectible by anthropophilic and zoophilic strains of dermatophytes. T. rubrum infection continued for a maximum of 9 weeks and T. mentagrophytes infection for more than 11 weeks. In the animals inoculated with T. mentagrophytes, fungal elements were localized in the stratum corneum of the human skin grafts. In the acute stage, microabscesses consisting of neutrophils were observed under the stratum corneum in contact with fungal elements; in the chronic stage, epidermal thickening and infiltration, mainly consisting of histiocytes and a smaller number of lymphocytes, was noted in the upper and middle dermis. Ultrastructural findings from the parasites were similar to those of dermatophytosis in man. This experimental system should be useful as a model of chronic dermatophyte infection in the human skin. 相似文献