全文获取类型
收费全文 | 2373篇 |
免费 | 151篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 58篇 |
妇产科学 | 117篇 |
基础医学 | 323篇 |
口腔科学 | 71篇 |
临床医学 | 304篇 |
内科学 | 383篇 |
皮肤病学 | 24篇 |
神经病学 | 245篇 |
特种医学 | 187篇 |
外科学 | 301篇 |
综合类 | 55篇 |
一般理论 | 1篇 |
预防医学 | 171篇 |
眼科学 | 49篇 |
药学 | 145篇 |
中国医学 | 1篇 |
肿瘤学 | 69篇 |
出版年
2021年 | 19篇 |
2019年 | 19篇 |
2018年 | 20篇 |
2017年 | 21篇 |
2016年 | 22篇 |
2015年 | 30篇 |
2014年 | 31篇 |
2013年 | 63篇 |
2012年 | 101篇 |
2011年 | 104篇 |
2010年 | 53篇 |
2009年 | 49篇 |
2008年 | 89篇 |
2007年 | 138篇 |
2006年 | 105篇 |
2005年 | 93篇 |
2004年 | 89篇 |
2003年 | 103篇 |
2002年 | 88篇 |
2001年 | 89篇 |
2000年 | 92篇 |
1999年 | 84篇 |
1998年 | 47篇 |
1997年 | 57篇 |
1996年 | 40篇 |
1995年 | 43篇 |
1994年 | 34篇 |
1993年 | 30篇 |
1992年 | 59篇 |
1991年 | 53篇 |
1990年 | 47篇 |
1989年 | 53篇 |
1988年 | 46篇 |
1987年 | 52篇 |
1986年 | 58篇 |
1985年 | 40篇 |
1984年 | 27篇 |
1983年 | 35篇 |
1982年 | 17篇 |
1981年 | 18篇 |
1980年 | 15篇 |
1979年 | 32篇 |
1978年 | 32篇 |
1977年 | 26篇 |
1976年 | 27篇 |
1975年 | 17篇 |
1974年 | 17篇 |
1971年 | 16篇 |
1970年 | 22篇 |
1967年 | 14篇 |
排序方式: 共有2571条查询结果,搜索用时 15 毫秒
1.
A surgical technique was used to establish chronic intestinal ulcers in Sprague-Dawley rats. A 2-cm-long segment of the distal ileum was excised and left attached on the mesentery. The ileum was reanastomosed. The excluded ileal segment formed a 'cyst' of various sizes. Initially, the anastomoses healed well, but after 6-8 weeks para-anastomotic ulcers developed in more than 50% of the rats. Histopathology showed a chronic inflammatory reaction with a predominance of mononuclear cells and increased numbers of eosinophilic granulocytes. The surface of the ulcers was covered with bacteria. Penetrating ulcers with fistula formation occurred. It is concluded that this experimental model may be useful for time sequential studies of the development of chronic and ulcerative ileitis. It may also be used to study the effect of medical and surgical regimens for the treatment of non-specific chronic inflammatory bowel disease. 相似文献
2.
Use of sonography to evaluate carotid atherosclerosis in the elderly. The Cardiovascular Health Study. CHS Collaborative Research Group 总被引:10,自引:0,他引:10
D H O'Leary J F Polak S K Wolfson M G Bond W Bommer S Sheth B M Psaty A R Sharrett T A Manolio 《Stroke; a journal of cerebral circulation》1991,22(9):1155-1163
Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies. 相似文献
3.
4.
Between 1969 and 1993, 123 patients were accepted in this unit for surgery for refractory hyperparathyroidism associated with chronic renal failure. Subtotal parathyroidectomy was the procedure of choice. At operation, four or more parathyroids were identified in 75% of patients. Methylene blue localised additional parathyroids in 32% of initial explorations in which it was used. Coincidental thyroid pathology was found in 8.3%, including papillary carcinoma in 2.4%. No further parathyroid surgery was required in 90% of patients at a mean of 6.6 years after operation. Reoperation (10%) was more likely to be required (14.3%) when less than four glands were found than when four or more were found (8.5%). Patients continuing on dialysis were more likely to need reoperation than those with functioning renal transplants. 相似文献
5.
6.
7.
8.
Topographic order in the rat retinocollicular projection emerges from an initially diffuse projection during an early postnatal remodeling period that is coincident with the period of naturally occurring ganglion cell death. Here, we examine the relationship between a retinal axon's position along the medial-lateral axis as it enters the superior colliculus (SC) and its ability to form an appropriately positioned arbor and survive the remodeling period. At E18-E19, prior to map remodeling, axons labeled with focal DiI injections in the periphery of temporal, nasal, superior or inferior retina are widespread along the medial-lateral SC axis. At P12, after remodeling, the distributions of axons remain widespread over the medial-lateral SC axis relative to the positioning of their terminal arborizations, and resemble the distributions labeled at E18-E19, with the exception that the small proportion of axons most widely mispositioned along the medial-lateral SC axis are less frequent. These data indicate that the most widely mispositioned retinal axons are preferentially eliminated, but that a high proportion of retinal axons mispositioned along the medial-lateral axis as they enter the SC can correct their position, form topographically appropriate arbors, and survive the remodeling period. 相似文献
9.
Hypertension in neuroblastoma induced by imipramine 总被引:1,自引:0,他引:1
J Feusner M O'Leary B Beach 《The American journal of pediatric hematology/oncology》1987,9(4):305-307
Hypertension is a well-known finding in some patients with neuroblastoma. However, it has not previously been described in association with the use of Imipramine. We report the occurrence of severe hypertension (blood pressure 190/160) in a 4-year-old girl with neuroblastoma who was given Imipramine to control a behavior disorder. It was determined later that this patient's tumor was recurring at the time of her hypertensive episode. Since she had no blood pressure elevation at initial diagnosis and none following discontinuation of the Imipramine (when she was in florid relapse), we believe that this drug rather than her underlying disease alone caused her hypertension. The mechanism for this reaction is believed to be increased levels of vasoactive catecholamines due to interference of their physiologic inactivation by Imipramine. From this experience, we urge extreme caution in the use of tricyclic antidepressants in children with active neuroblastoma. 相似文献
10.
Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations 总被引:2,自引:0,他引:2
Hulnick DH; Megibow AJ; Balthazar EJ; Gordon RB; Surapenini R; Bosniak MA 《Radiology》1987,164(3):611-615
Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm. 相似文献