全文获取类型
收费全文 | 23631篇 |
免费 | 2467篇 |
国内免费 | 638篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 1827篇 |
妇产科学 | 519篇 |
基础医学 | 1758篇 |
口腔科学 | 456篇 |
临床医学 | 2692篇 |
内科学 | 3577篇 |
皮肤病学 | 191篇 |
神经病学 | 1190篇 |
特种医学 | 682篇 |
外国民族医学 | 4篇 |
外科学 | 1535篇 |
综合类 | 2453篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 5411篇 |
眼科学 | 554篇 |
药学 | 1889篇 |
16篇 | |
中国医学 | 821篇 |
肿瘤学 | 1082篇 |
出版年
2024年 | 43篇 |
2023年 | 445篇 |
2022年 | 1347篇 |
2021年 | 1646篇 |
2020年 | 1075篇 |
2019年 | 1068篇 |
2018年 | 1004篇 |
2017年 | 975篇 |
2016年 | 979篇 |
2015年 | 1008篇 |
2014年 | 1550篇 |
2013年 | 1979篇 |
2012年 | 1311篇 |
2011年 | 1329篇 |
2010年 | 1090篇 |
2009年 | 925篇 |
2008年 | 983篇 |
2007年 | 981篇 |
2006年 | 813篇 |
2005年 | 750篇 |
2004年 | 619篇 |
2003年 | 586篇 |
2002年 | 473篇 |
2001年 | 419篇 |
2000年 | 368篇 |
1999年 | 290篇 |
1998年 | 259篇 |
1997年 | 270篇 |
1996年 | 245篇 |
1995年 | 176篇 |
1994年 | 180篇 |
1993年 | 153篇 |
1992年 | 152篇 |
1991年 | 134篇 |
1990年 | 99篇 |
1989年 | 103篇 |
1988年 | 100篇 |
1987年 | 83篇 |
1986年 | 72篇 |
1985年 | 109篇 |
1984年 | 92篇 |
1983年 | 74篇 |
1982年 | 79篇 |
1981年 | 75篇 |
1980年 | 64篇 |
1979年 | 31篇 |
1978年 | 36篇 |
1977年 | 22篇 |
1976年 | 20篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
C. I. V. FRANKLIN 《Journal of Medical Imaging and Radiation Oncology》1991,35(1):68-71
The records of 108 adult patients with supratentorial low grade astrocytoma presenting between 1/1/80 and 31/12/87 were examined for the following factors which might affect survival: patient age, extent of surgical resection, site of tumour, tumour grade, radiation field size and radiation dose. Univariate analysis showed that patient age, field size and radiation dose were significant prognostic factors, but with multivariate analysis only patient age and radiation field size were significant independent variables. It is possible that field size is a proxy variable for tumour size. 相似文献
22.
23.
Zongli Lin Meir Pachter Siva Banda Yacov Shamash 《Optimal control applications & methods.》2002,23(1):21-43
A design technique (Control of Uncertain Systems with Bounded Inputs, Tarbouriech S, Garcia G, (Eds), Lecture Notes in Control and Information Sciences, vol. 227 , Springer: Berlin, 1997; 173–186) recently proposed for stabilization of a linear system with rate‐limited actuators is utilized to design feedback laws that cause the system output to track a desired command signal. This design technique combines two design techniques recently developed for linear systems with position limited actuators, piecewise‐linear LQ control (Automatica, 1994; 30 : 403–416) and low‐and‐high gain feedback (IEEE Trans. Automat. Control, 1996; 41 : 368–378), and hence takes advantage of both design techniques, while avoiding their disadvantages. In the case that only the output is available for feedback, the performance of the state feedback law is preserved by the use of a fast observer. An open‐loop exponentially unstable fighter aircraft is used to demonstrate the effectiveness of the proposed control design method. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
24.
河南食管癌高、低发区无症状人群食管固有膜血管乳头的变化 总被引:2,自引:1,他引:1
目的:探讨食管癌高、低发区无症状居民食管上皮固有膜血管乳头(简称乳头)增生特征(乳头密度和高度)及其与病变分布的关系,加深对食管癌变早期形态学变化特征的了解。方法:2480例无症状人群食管粘膜活检组织,采用食管癌高低发区食管纤维内镜检查,粘膜活检,组织病理学检查和形态学测量技术对食管乳头的分布特征及其与病变的关系进行分析。结果:食管癌高低发区居民食管中、下段乳头升高(≥上皮厚度的1/2)发生率之间差异并不明显(P>0.05),但是,高发区居民食管中段乳头密度(乳头数目/mm)明显高于下段,并高于低发区居民食管中段的乳头密度(P<0.05);高发区居民食管上皮乳头升高伴基底细胞过度增生患者明显高于正常人(P<0.05),而低发区未观察到类似情况。结论:乳头增生表现为乳头数目增多和乳头升高是食管癌高发区人群食管上皮特征性形态学变化,高分区居民上皮乳头升高伴明显基底细胞过度增生,提示乳头增生可能是食管癌变极早期阶段的重要形态学变化,反映了上皮细胞的增生状态。 相似文献
25.
26.
J.K. MOHANA RAO 《Chemical biology & drug design》1987,29(2):276-281
Based on residue characteristic physical parameters, a new scoring matrix, called EMPAR, for amino acid exchanges in proteins was obtained. When comparing protein sequences for detecting homologies, the use of this matrix in place of the Dayhoff log-odds matrix yields results that reflect the topological similarities in the proteins. The use of EMPAR is equivalent to the parametric correlation coefficient approach of Ooi and his colleagues. This matrix correlates at 0.63 with the Dayhoff matrix. 相似文献
27.
M. P. Gosselink J. J. Busschbach† C. M. Dijkhuis§ L. P. Stassen¶ W. C. Hop‡ W. R. Schouten 《Colorectal disease》2006,8(1):15-22
BACKGROUND: After total mesorectal excision for rectal cancer, many surgeons try to avoid an abdominoperineal resection (APR) by performing a transanally double stapled low colo-rectal anastomosis (LRA), frequently without a pouch. This policy is mainly based on the assumption that the quality of life after such LRA is higher than after APR. It has been suggested that a better functional outcome and therefore a higher quality of life might be achieved by a colo-anal J-pouch anastomosis (CPA). The aim of this study was to assess quality of life among disease-free survivors after APR, LRA and CPA. METHODS: The charts of 301 consecutive patients who had undergone surgery for cancer in the middle or lower third of the rectum were analysed. Two hundred four patients were eligible for inclusion. The quality of life among these patients was assessed using one generic (EQ-5D) and two disease-specific questionnaires (EORTC QLQ-C30 and EORTC QLQ-CR38). RESULTS: The response rate was 82%. The median follow-up was 31 months. Overall, quality of life was good but CPA patients had better quality of life scores than APR and LRA patients. This difference was not only due to the better functional outcome but also to the lower incidence of disturbed micturition and sexual problems in the CPA group. CONCLUSION: The quality of life after colo-anal J-pouch anastomosis is better than after abdominoperineal resection (APR) and low colo-rectal anastomosis (LRA). The quality of life after APR is similar to that after LRA. 相似文献
28.
Henry Ho‐Lung Chan 《Clinical & experimental optometry》2005,88(6):410-414
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma. 相似文献
29.
目的:为了探讨非依赖型糖尿病全血低切变率粘度值测定的临床意义。方法:对91例非依赖型糖尿病血液流变学低切率粘度值进行了检测,并对其结果及形成机制进行了分析讨论。结果:91例非依赖型糖尿病低切变率粘度值和对照组相比有显著性差异,p<0.01。结论:非依赖型糖尿病全血低切变率粘度增高,可造成微血管循环障碍,是非依赖型糖尿病易形成心梗、脑梗及其他微血管病的一种重要因素。 相似文献
30.
目的 探讨如何选择合适的保肛手术方法治疗低位直肠癌。方法 44例肿块下缘距肛缘5~7cm的低位直肠癌患者,对21例采用改良的结肠肛管吻合术(A组)、23例应用吻合器技术的前切除术(B组)进行治疗;并对两组疗效予以对比。结果 A组患者无远端直肠残端肿瘤残留,B组有2例。肿瘤远端直肠切除距离A组平均为(2.81±0.35)cm,B组(1.73±0.42)cm。两组比较,差异有显著性意义(t=9.083,P<0.001)。A组术后两年均无吻合口复发,B组有4例,B组吻合口复发率明显高于A组(x~2=4.234,P=0.04)。A组术后早期排便功能较差,但均能在半年内改善;B组术后排便功能良好。结论 低位直肠癌患者肿瘤下缘距肛缘5~7cm、肿瘤“T”分期为Ⅱ、Ⅲ期、术前指诊肿瘤可推动、肿瘤侵犯肠壁范围不到1周可行保肛手术。应根据患者体型、骨盆宽窄、肿瘤分化程度及其侵犯肠管的周径合理选择改良的结肠肛管吻合术或吻合器技术的前切除术。 相似文献