全文获取类型
收费全文 | 2347422篇 |
免费 | 176227篇 |
国内免费 | 5858篇 |
专业分类
耳鼻咽喉 | 32364篇 |
儿科学 | 79309篇 |
妇产科学 | 64487篇 |
基础医学 | 339652篇 |
口腔科学 | 63722篇 |
临床医学 | 218748篇 |
内科学 | 456872篇 |
皮肤病学 | 48996篇 |
神经病学 | 190690篇 |
特种医学 | 88874篇 |
外国民族医学 | 912篇 |
外科学 | 341042篇 |
综合类 | 51841篇 |
现状与发展 | 2篇 |
一般理论 | 805篇 |
预防医学 | 191732篇 |
眼科学 | 52129篇 |
药学 | 174080篇 |
7篇 | |
中国医学 | 5078篇 |
肿瘤学 | 128165篇 |
出版年
2019年 | 18648篇 |
2018年 | 26226篇 |
2017年 | 19782篇 |
2016年 | 21618篇 |
2015年 | 24653篇 |
2014年 | 34160篇 |
2013年 | 52702篇 |
2012年 | 72310篇 |
2011年 | 76722篇 |
2010年 | 45161篇 |
2009年 | 42246篇 |
2008年 | 71467篇 |
2007年 | 76045篇 |
2006年 | 76333篇 |
2005年 | 74034篇 |
2004年 | 71367篇 |
2003年 | 68614篇 |
2002年 | 66766篇 |
2001年 | 108100篇 |
2000年 | 111897篇 |
1999年 | 94491篇 |
1998年 | 26699篇 |
1997年 | 24131篇 |
1996年 | 24219篇 |
1995年 | 23041篇 |
1994年 | 21747篇 |
1993年 | 20293篇 |
1992年 | 75666篇 |
1991年 | 74165篇 |
1990年 | 71956篇 |
1989年 | 68526篇 |
1988年 | 63382篇 |
1987年 | 62214篇 |
1986年 | 58662篇 |
1985年 | 56125篇 |
1984年 | 42366篇 |
1983年 | 35843篇 |
1982年 | 21202篇 |
1981年 | 19145篇 |
1979年 | 38163篇 |
1978年 | 26955篇 |
1977年 | 22444篇 |
1976年 | 21523篇 |
1975年 | 22674篇 |
1974年 | 27105篇 |
1973年 | 26352篇 |
1972年 | 24289篇 |
1971年 | 22359篇 |
1970年 | 20980篇 |
1969年 | 19025篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
Keratography as a guide to selective suture removal for the reduction of astigmatism after penetrating keratoplasty 总被引:2,自引:0,他引:2
After penetrating keratoplasty in 52 eyes, keratography refraction and keratometry were used to select appropriate interrupted sutures for removal in order to reduce astigmatism. All eyes had one continuous and either 12 or 16 interrupted nylon sutures. The keratographs were examined retrospectively and separated into six groups on the basis of similar mire patterns. The removal of single sutures associated with three of these patterns reduced astigmatism by the following average amounts: symmetrical oval pattern, 0.44 diopters (D); D-shaped oval pattern, 2.07 D; and focal indentation pattern, 6.60 D. The other three patterns--mildly disrupted mires, incomplete mires, and uninterpretable mires--did not allow quantification of results. Examples of these keratographic patterns are presented and recommendations are made for their use in the management of astigmatism following penetrating keratoplasty. 相似文献
942.
A study on the pathologic findings after recession and resection of extraocular muscles in rabbits was performed. Fibrosis of the extraocular muscles increased with time, which showed no difference between the recessed and resected muscles. Inflammation and foreign body reaction decreased with time, which showed no difference between the recessed and resected muscles. Adhesions of extraocular muscles to the sclera were observed from one month after the operation. The resected muscles showed milder adhesion to the sclera than the recessed ones. The operated extraocular muscles showed atrophies at one month, which showed no difference between the recessed and resected muscles. According to our results, when reoperation is needed, fibrosis of the extraocular muscles after recession and resection should be considered when making a decision on the amount of muscle to be recessed and resected. 相似文献
943.
N-Hydroxythalidomide (1d), a potential metabolite of thalidomide (1a), was synthesized from N-phthalyglutaminic acid anhydride (1b) and O-tetrahydropyraline hydroxylamine, followed by deprotection. The teratogenicity of 1d was studied using the Hen's-Egg-Test model which had been found applicable for 1a. 1d was more teratogenic to chicken embryos compared to 1a. The percentage of teratogenic malformations in the 1d groups was 28-46%, whereas the percentage in the 1a groups was 20-23%. The oxygen protected precursor N-hydroxythalidomide (1c) was less teratogenic (11-15%). 相似文献
944.
The distribution of tyrosine-hydroxylase (TH)-immunoreactive cell bodies and fibers in the diencephalon has been investigated with immunohistological techniques in the pigeon. The results suggest that TH is present in a number of morphologically distinct neuronal systems. Preoptic and hypothalamic TH neurons were subdivided into a medial periventricular and a lateral group. The medial group starts with a rostral collection of small cells in the preoptic region. A significantly larger collection of TH neurons occupies the paraventricular nucleus (PVN) (stratum cellulare internum) and mainly consists of large multipolar cells. Further caudally, the main concentration of cells is in the hypothalamic posteromedial and the periventricular regions of the tuberoinfundibular (arcuate) nucleus. No TH neuron was found in the ventral and lateral parts of the tuberoinfundibular region, suggesting that the prominent tuberoinfundibular dopaminergic system described in mammals is absent in the pigeon. This further substantiated by the relative scarcity of TH immunoreactive fibers and varicosities in the neurohemal zone of the median eminence (ME). The caudalmost components of the medial group appear to be continuous with the large population of TH neurons distributed in the midline of the mesencephalon. Tyrosine-hydroxylase-immunopositive cells have not been found in the paraventricular organ. The lateral group consists of TH neurons loosely arranged in the lateral hypothalamus, including regions of the supraoptic nucleus and hypothalamic posterolateral nucleus. Tyrosine-hydroxylase containing neurons vary widely in size, shape, and dendritic arborization in each diencephalic region. However, it is possible to distinguish two main cell types. Small bipolar neurons with two simple arborizing dendrites were concentrated in the medial periventricular system. The second type of cell is large, multipolar with four to five branching dendrites. This latter cell type occurs mainly in the lateral system and in the PVN. Major fiber bundles containing TH immunoreactivity were identified in the lateral and periventricular hypothalamus. The paraventricular organ and the organum vasculosum laminae terminalis contained the densest arborization of fibers and varicosities. In the ME, dense innervation was found in the subependymal layer. Dense arborizations of TH positive fibers and varicosities were located in the septal nuclei and the paleostriatum augmentatum. 相似文献
945.
Topographic electroencephalography was carried out to study reaction to photic stimulation in 29 normal volunteers, and 12 patients who had presented frequent clinically confirmed migraines for at least 3 years. In the group of migraineurs photic stimulation resulted in an increase in the alpha band power. The difference between the two groups was statistically significant. This reaction to photic stimulation is of help in diagnosis and suggests that a diagnosis and therapeutic orientation might be possible in patients for whom clinical diagnosis is not clear. The specificity of the migraineur's reaction to photic stimulation and its possible origin are discussed. 相似文献
946.
947.
948.
L H Toledo-Pereyra C Gordon R Kaufmann J I Whitten V K Mittal 《The American surgeon》1987,53(9):534-536
The role of timing of transplant nephrectomy after renal transplantation has not been well defined. This report compares the morbidity, mortality, and hospitalization costs of 37 patients undergoing transplant nephrectomy within 14 days after graft failure and return to dialysis, with 31 patients undergoing delayed transplant nephrectomy (less than 14 days after graft failure and return to dialysis). This analysis revealed that there were no significant (P greater than .05) differences in patient morbidity and mortality between these groups. There was, however, a substantial increase (P less than .05) in the cost of hospitalization in the delayed nephrectomy group. For this reason, we recommend early nephrectomy after renal transplant failure in order to minimize the cost of health care for these patients undergoing failed cadaver donor transplant nephrectomy. 相似文献
949.
J. J. KEUR J. P. S. CAMPBELL J. F. McCARTHY W. J. RALPH 《Journal of oral rehabilitation》1987,14(2):183-191
A sample consisting of 1135 edentulous patients with clinically healthy denture bearing areas, was examined radiologically. It appears that the diagnostic yield is high whereas the expected radiation induced risk is low. Patients should therefore be examined radiologically prior to full denture construction. 相似文献
950.
In a series of 75 spines studied at autopsy, the authors found 21 (28%) affected by ankylosing hyperostosis. The 21 cases included three in the cervical spine, 12 in the thoracic spine, and five in the lumbar spine. One case had both thoracic and lumbar spine disease. The average age was 65 years (range, 50-90 years). The mean weight was 85 kg, which was 20 kg more than the mean weight of the nonaffected subjects. Four cases had adult onset diabetes mellitus. No other endocrine or arthritic disease was noted either clinically or at autopsy. No abnormalities of calcium or phosphorus metabolism were found. The cause of death was unrelated to their spine disease, and clinical records were devoid of any major complaints referable to the spine. 相似文献