全文获取类型
收费全文 | 543656篇 |
免费 | 36555篇 |
国内免费 | 26256篇 |
专业分类
耳鼻咽喉 | 4617篇 |
儿科学 | 10499篇 |
妇产科学 | 8201篇 |
基础医学 | 59981篇 |
口腔科学 | 8360篇 |
临床医学 | 63768篇 |
内科学 | 84874篇 |
皮肤病学 | 4256篇 |
神经病学 | 35853篇 |
特种医学 | 22808篇 |
外国民族医学 | 225篇 |
外科学 | 66531篇 |
综合类 | 64131篇 |
现状与发展 | 92篇 |
一般理论 | 26篇 |
预防医学 | 42163篇 |
眼科学 | 13419篇 |
药学 | 47730篇 |
405篇 | |
中国医学 | 22211篇 |
肿瘤学 | 46317篇 |
出版年
2024年 | 1247篇 |
2023年 | 5805篇 |
2022年 | 15195篇 |
2021年 | 19077篇 |
2020年 | 14405篇 |
2019年 | 12458篇 |
2018年 | 33783篇 |
2017年 | 28332篇 |
2016年 | 29635篇 |
2015年 | 17757篇 |
2014年 | 21795篇 |
2013年 | 19518篇 |
2012年 | 34460篇 |
2011年 | 51167篇 |
2010年 | 37958篇 |
2009年 | 26863篇 |
2008年 | 39714篇 |
2007年 | 41482篇 |
2006年 | 20408篇 |
2005年 | 21178篇 |
2004年 | 15393篇 |
2003年 | 15173篇 |
2002年 | 11768篇 |
2001年 | 8448篇 |
2000年 | 9340篇 |
1999年 | 9623篇 |
1998年 | 5903篇 |
1997年 | 5911篇 |
1996年 | 4593篇 |
1995年 | 4179篇 |
1994年 | 3420篇 |
1993年 | 2242篇 |
1992年 | 2944篇 |
1991年 | 2565篇 |
1990年 | 2304篇 |
1989年 | 1985篇 |
1988年 | 1652篇 |
1987年 | 1419篇 |
1986年 | 1154篇 |
1985年 | 959篇 |
1984年 | 551篇 |
1983年 | 401篇 |
1982年 | 270篇 |
1981年 | 244篇 |
1980年 | 230篇 |
1979年 | 226篇 |
1978年 | 94篇 |
1977年 | 93篇 |
1974年 | 123篇 |
1973年 | 85篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Nan-Fu Chen Yeou-Chih Wang Chiung-Chyi Shen Yee-Jee Jan Wen-Hsien Chen Ching-Hsiang Leu 《Journal of clinical neuroscience》2004,11(5):527-530
We report a case of calcified chronic encapsulated intracerebral haematoma (ICH) in a 29-year-old female who presented with progressive left sided weakness and intermittent seizures since childhood. The preoperative magnetic resonance (MR) imaging of the head initially suggested that a partially thrombosed aneurysm or vascular malformation was present. However, no vascular stain was found on the digital subtraction angiography (DSA) of both the carotid and vertebral arteries. The excised mass was histologically diagnosed as a chronic ICH. We traced the patient's medical history and found that at the age of one she sustained a head injury after a fall. So far, to our knowledge, no case of epilepsy secondary to a calcified chronic encapsulated ICH occurring 28 years after head injury has been reported. Calcified chronic encapsulated ICH concomitant with new bone formation within is even rarer. The possible pathogenesis of this case is discussed. 相似文献
942.
Kuo-Sheng Hung MD Phd Chung-Ling Liang MD Cheng-Haung Wang MD Hsueh-Wen Chang PhD Naeun Park MS Suh-Hang Hank Juo MD PhD 《Journal of clinical neuroscience》2004,11(8):849-853
Frontal intracerebral haemorrhage (ICH) is a common result of cranial trauma. Outcome differences between bilateral and unilateral frontal ICH are not well studied but would be valuable to predict prognosis in clinical practice. Two aims are proposed in this study: first to compare the risk of developing delayed ICH after bilateral or unilateral frontal ICH, and second to determine the variables helpful to predict outcome according to the Glasgow Outcome Scale (GOS). Between January 1993 and December 1997, 694 consecutive patients with traumatic ICH were admitted to the Chang Gung Medical Center within 24 h of the trauma. Patients with ICH in sites other than the frontal lobes were excluded. A total of 161 cases (mean age 46.3+/-20.3 years), including 57 bilateral (mean age 52.5+/-18.7 years) and 104 unilateral (mean age 42.9+/-20.5 years) traumatic frontal ICH were studied. Twenty-eight of 57 patients (49%) with bifrontal ICH versus 17 of 104 patients (16%) with unilateral frontal ICH had a further, delayed ICH. In 42 of 45 patients (93%) with delayed ICH, this occurred within 5 days of the initial trauma. Multivariate logistic regression was used to select significant predictors of outcome. We found that delayed ICH (p<0.001), age (p=0.004) and mechanism of injury (p=0.001) explained the worse outcome in patients with bifrontal ICH. The best-fitting logistic regression model included three variables: delayed ICH (p=0.011), initial GCS (p=0.023), and a sum score of clinical and radiological variables (p=0.003). Bifrontal ICH tended to occur in older patients after a fall and was associated with a higher risk of developing delayed ICH or brain stem compression compared to unilateral ICH damage. Using these three variables - delayed ICH, initial GCS, and the sum score - in a logistical regression model is useful to predict outcome in patients with traumatic frontal ICH and may aid patient management. 相似文献
943.
Takeshi Sakata Yongmei Wang Bernard P Halloran Hashem Z Elalieh Jay Cao Daniel D Bikle 《Journal of bone and mineral research》2004,19(3):436-446
We showed that unloading markedly diminished the effects of IGF-I to activate its signaling pathways, and the disintegrin echistatin showed a similar block in osteoprogenitor cells. Furthermore, unloading decreased alphaVbeta3 integrin expression. These results show that skeletal unloading induces resistance to IGF-I by inhibiting activation of the IGF-I signaling pathways at least in part through downregulation of integrin signaling. INTRODUCTION: We have previously reported that skeletal unloading induces resistance to insulin-like growth factor-I (IGF-I) with respect to bone formation. However, the underlying mechanism remains unclear. The aim of this study was to clarify how skeletal unloading induces resistance to the effects of IGF-I administration in vivo and in vitro with respect to bone formation. MATERIALS AND METHODS: We first determined the response of bone to IGF-I administration in vivo during skeletal unloading. We then evaluated the response of osteoprogenitor cells isolated from unloaded bones to IGF-I treatment in vitro with respect to activation of the IGF-I signaling pathways. Finally we examined the potential role of integrins in mediating the responsiveness of osteoprogenitor cells to IGF-I. RESULTS: IGF-I administration in vivo significantly increased proliferation of osteoblasts. Unloading markedly decreased proliferation and blocked the ability of IGF-I to increase proliferation. On a cellular level, IGF-I treatment in vitro stimulated the activation of its receptor, Ras, ERK1/2 (p44/42 MAPK), and Akt in cultured osteoprogenitor cells from normally loaded bones, but these effects were markedly diminished in cells from unloaded bones. These results were not caused by altered phosphatase activity or changes in receptor binding to IGF-I. Inhibition of the Ras/MAPK pathway was more impacted by unloading than that of Akt. The disintegrin echistatin (an antagonist of the alphaVbeta3 integrin) blocked the ability of IGF-I to stimulate its receptor phosphorylation and osteoblast proliferation, similar to that seen in cells from unloaded bone. Furthermore, unloading significantly decreased the mRNA levels both of alphaV and beta3 integrin subunits in osteoprogenitor cells. CONCLUSION: These results indicate that skeletal unloading induces resistance to IGF-I by inhibiting the activation of IGF-I signaling pathways, at least in part, through downregulation of integrin signaling, resulting in decreased proliferation of osteoblasts and their precursors. 相似文献
944.
945.
946.
目的 研制新型胫骨串孔型髓内钉并对其进行生物力学研究。方法 用TAMZ合金制造远端锁孔由一个三个同样直径的串孔所替代的 9根新型胫骨髓内钉。将髓内钉安装在自行设计的夹具中 ,先将 3根新钉进行静态垂直压缩实验 ,根据静态实验结果 ,分别测试 6根新钉的动态疲劳强度。结果 新钉的静态压缩破坏载荷为 2 1 33N ,是人平均体重的 3倍多 ;通过 5 0万次压缩循环的条件疲劳强度为 1 2 0 0N ,约是人体重的 2倍。结论 新钉不仅能够方便临床使用 ,而且拥有较好的力学特性 相似文献
947.
Antegrade interlocking nailing of humeral shaft fractures 总被引:5,自引:0,他引:5
George Petsatodes Dimitrios Karataglis Pericles Papadopoulos John Christoforides John Gigis John Pournaras 《Journal of orthopaedic science》2004,9(3):247-252
The results of 39 humeral shaft fractures (37 patients) treated with antegrade locked nailing using a Russell–Taylor nail were reviewed. There were 30 acute fractures, 6 fractures malaligned in a hanging cast or brace, and 3 pathological fractures. Patient age ranged from 26 to 80 years (average, 59.7 years) and average follow-up was 25.7 months (range, 6–48 months). Fracture union was achieved in 92.3% of our cases, while shoulder function was excellent or good in 87.2% of cases. Antegrade locked nailing offers a dependable solution for the treatment of humeral shaft fractures, especially in polytrauma patients and cases of segmental or pathological fractures. Far less satisfactory results were obtained in comminuted fractures of the proximal third in the humerus, especially in osteoporotic patients, and we therefore advocate caution with the use of intramedullary nailing in this type of fracture. Certain technical aspects such as avoiding nailing the fracture in distraction, properly countersinking the tip of the nail, and achieving adequate fixation stability have been found to be of paramount importance to reduce the incidence of delayed union/non-union rate and to obtain better functional results from the shoulder joint. 相似文献
948.
Sadao Ii Hiroyuki Tsuchiya Koutaro Takazawa Hiroshi Minato Katsuro Tomita 《Journal of orthopaedic science》2004,9(2):152-156
Adamantinoma is a rare low-grade malignant bone tumor with an indolent course. The tibia is involved in 85%–90% of long-bone cases. We encountered a patient with primary adamantinoma of the proximal femur. A 60-year-old woman fell and fractured her proximal left femur in the area of a cystic lesion. She underwent an osteosynthesis procedure, and bone union was obtained. After 3 years she developed pain in the left thigh, and a radiographic abnormality was found at the fracture site. A metastatic bone tumor was suspected, and curettage and cementing were carried out. Histologically, we found an epithelial component but failed to detect any primary cancer. Local recurrence became evident after another 6 years. A marginal excision was performed and a bipolar femoral prosthesis was implanted. We finally diagnosed the patient with adamantinoma. In this report we describe the characteristics of this tumor and discuss the reasoning concerning the differential diagnosis and therapeutic plan. 相似文献
949.
Koichi Fujiu Ryuzo Kanno Yutaka Shio Jyun Ohsugi Yoshihiro Nozawa Mitsukazu Gotoh 《General thoracic and cardiovascular surgery》2004,52(7):345-348
A 36-year-old woman complained of cough and high fever. Computed tomographic scans demonstrated a mediastinal mass. A couple of months later, she developed dryness in her eyes and mouth. Biopsy of the lip confirmed the diagnosis of Sjögren’s syndrome. She underwent thymo-thymomectomy. Pathological findings of the mass revealed thymoma. At two months after surgery, she developed ptosis and dysphagia that were compatible with myasthenia gravis. The clinical symptoms were adequately controlled with prednisolone. At eleven months after surgery, she presented with severe anemia, which led to the diagnosis of pure red cell aplasia. The following treatment with cyclosporin caused hemoglobin concentration to rise. However, she continues to suffer from dryness of her eyes and mouth. The case is the first to be reported with Sjögren’s syndrome and the triad of thymoma, myasthenia gravis and pure red cell aplasia, and is compared with previously reported cases of the three conditions. 相似文献
950.
软骨细胞老化特征及机制的研究进展 总被引:3,自引:0,他引:3
软骨细胞的老化是一个极其复杂的过程,其特征包括:细胞不可逆的生长停滞于G1期;老化相关β-半乳糖苷酶的表达;端粒长度缩短;软骨细胞分化特征的改变。目前认为其机制为基因表达的程序性或减进性改变,包括肿瘤抑制基因p53和pRb等在细胞生长停滞中的作用;端粒结合蛋白和端粒酶对端粒长度的调节;细胞骨架蛋白的重组使软骨细胞形态的变化;基质降解酶类表达增加以及各种细胞因子的变化对软骨细胞代谢的影响。 相似文献