全文获取类型
收费全文 | 497968篇 |
免费 | 30789篇 |
国内免费 | 3913篇 |
专业分类
耳鼻咽喉 | 7074篇 |
儿科学 | 10160篇 |
妇产科学 | 11838篇 |
基础医学 | 71528篇 |
口腔科学 | 14789篇 |
临床医学 | 41295篇 |
内科学 | 99750篇 |
皮肤病学 | 12138篇 |
神经病学 | 36893篇 |
特种医学 | 20601篇 |
外国民族医学 | 82篇 |
外科学 | 75760篇 |
综合类 | 10489篇 |
现状与发展 | 4篇 |
一般理论 | 89篇 |
预防医学 | 24036篇 |
眼科学 | 12490篇 |
药学 | 41744篇 |
1篇 | |
中国医学 | 3556篇 |
肿瘤学 | 38353篇 |
出版年
2022年 | 3931篇 |
2021年 | 7018篇 |
2020年 | 3775篇 |
2019年 | 5650篇 |
2018年 | 8072篇 |
2017年 | 6306篇 |
2016年 | 7344篇 |
2015年 | 9353篇 |
2014年 | 11912篇 |
2013年 | 14642篇 |
2012年 | 20937篇 |
2011年 | 20731篇 |
2010年 | 12193篇 |
2009年 | 10942篇 |
2008年 | 16685篇 |
2007年 | 17172篇 |
2006年 | 16367篇 |
2005年 | 15080篇 |
2004年 | 13811篇 |
2003年 | 12865篇 |
2002年 | 11920篇 |
2001年 | 29989篇 |
2000年 | 30350篇 |
1999年 | 24973篇 |
1998年 | 5926篇 |
1997年 | 4817篇 |
1996年 | 4248篇 |
1995年 | 3856篇 |
1994年 | 3432篇 |
1993年 | 3110篇 |
1992年 | 16578篇 |
1991年 | 15348篇 |
1990年 | 14644篇 |
1989年 | 14368篇 |
1988年 | 12926篇 |
1987年 | 12405篇 |
1986年 | 11380篇 |
1985年 | 10630篇 |
1984年 | 7131篇 |
1983年 | 5771篇 |
1982年 | 2839篇 |
1979年 | 5644篇 |
1978年 | 3475篇 |
1977年 | 3067篇 |
1975年 | 2730篇 |
1974年 | 3181篇 |
1973年 | 2972篇 |
1972年 | 2927篇 |
1971年 | 2844篇 |
1969年 | 2601篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Renal leiomyomas large enough to be clinically diagnosed are extremely rare. We review 30 cases of clinically diagnosed renal leiomyoma from the literature in Japan, including our 2 new cases. Case 1: In a 52-year-old man with no symptoms a renal mass was found accidentally on an ultrasonogram. CT scan showed a mass with a cystic area at the upper pole of the right kidney. Angiogram showed a hypovascular mass. Case 2: CT scan revealed a cystic mass and angiogram showed an avascular mass at the upper pole of the left kidney in a 19-year-old man having gross hematuria and left flank pain. Transperitoneal nephrectomy was done in both cases. Histologically each tumor was composed of monotonous proliferation of spindle shaped cells without atypia, which showed intense immunoreactivity for alpha-smooth muscle actin. The diagnosis of benign leiomyoma was made in each case. In a review of 30 cases, we found that renal leiomyomas occur most often in female (77%), between decades 2 and 5 of life (median: 46 years). On the angiogram it appears most often as an avascular or hypovascular mass. CT scan shows cystic or mixed solid/cystic or solid lesion, occasionally with calcification. Preoperative diagnosis is extremely difficult to be made. Histologically, fibroma, angiomyolipoma, congenital mesoblastic nephroma and leiomyosarcoma should be differentiated. 相似文献
992.
993.
Epidural spinal cord stimulation was carried out in 4 patients with denervation caused by spinal cord lesion, and we reviewed previously reported cases. Initial result showed at 1 week in 100% of our cases, but about 1/3 of the cases, even those with the same denervation caused by spinal cord lesion, had no pain relief at this stage in previously reported cases. In our cases, excellent pain relief was gained temporarily, even though the painful area and the spinal cord lesion were separated somatotopically in 2 cases (case 3, 4). Temporary success bore no relationship to quality and duration of pain. In all cases except case 1, a rapidly decreasing effectiveness was noted, and finally no pain relief was gained at all after 4, 3 and 5 months, respectively. In case 1 there was persistent pain relief estimated at 70-80% after 19 months, only when the spinal cord was stimulated. Epidural stimulation also produced sensations in the painful area. Spinal cord stimulation would suppress at least the dorsal horn neurons which were destroyed by various kinds of diseases. A decline in effectiveness with time would occur due to essential causes of the deafferentation pain, such as anatomical and regeneration factors. 相似文献
994.
995.
We present three unusual cases of molluscum contagiosum occurring in epidermal cysts. All of them are asymptomatic, elevated, oval nodules diagnosed clinically as epidermal inclusion cyst or prurigo nodularis. Histology showed true epidermal cysts containing molluscum bodies throughout the cyst wall and some type of laminated material within the cyst itself. The lesion, in all three cases developed in the pubic area of young adult men. 相似文献
996.
Résumé Un grand nombre de prothèses du coude sont actuellement disponibles, beaucoup de critères les opposent les unes aux autres.
Après les premières prothèses à charnière contrainte, les prothèses semicontraintes et plus récemment les prothèses à glissement
se sont imposées. La prothèse à glissement GUEPAR se situe dans l'évolution récente des implants du coude. Nous rapportons
ici les résultats des trente-neuf premières arthroplasties réalisées au sein du Guepar de 1986 à 1991, sur 33 coudes rhumato?des,
4 destructions post-traumatiques, 1 spondylarthrite ankylosante et 1 arthrose sur chondrocalcinose.
Nous remercions Mr J. H. Aubriot, M. Condamine, A Deburge, B Lassale, T Le Balc'h, J. Y. Nordin et J Witvoet, membres du GUEPAR (Groupe pour l'utilisation et l'étude des prothèses articulaires) de nous avoir donné leurs observations 相似文献
The Guepar total elbow arthroplasty
Summary The Guepar total elbow replacement is a low friction, minimally constrained gliding prosthesis. The humeral and ulnar components are of metal with intramedullary stems, which are cemented. There is a sigmoid shaped, high density polyethylene interposition bearing. The authors have used the prosthesis in 33 patients with rheumatoid arthritis, 4 with post-traumatic problems, one with chondrocalcinosis and another with degenerative changes of uncertain aetiology. In the patients with rheumatoid arthritis, one sustaine a posterior dislocation and two suffered deep infection. In the remaining 30, the overall results were good at an average review of 32 months. The mean range of movement had increased by 31° and pain was absent in 28 elbows. In the management of rheumatoid arthritis total elbow arthroplasty must be part of an overall plan of treatment. Severe involvement of the wrist and shoulder must be dealt with before elbow replacement is considered.
Nous remercions Mr J. H. Aubriot, M. Condamine, A Deburge, B Lassale, T Le Balc'h, J. Y. Nordin et J Witvoet, membres du GUEPAR (Groupe pour l'utilisation et l'étude des prothèses articulaires) de nous avoir donné leurs observations 相似文献
997.
S. F. Lee-Chen C. T. Yu D. R. Wu K. Y. Jan 《Environmental and molecular mutagenesis》1994,23(2):116-120
When Chinese hamster ovary cells were treated with ultraviolet (UV) light or methyl methanesulfonate (MMS), a large number of DNA strand breaks could be detected by alkaline elution. These strand breaks gradually disappeared if the treated cells were allowed to recover in a drug-free medium. The presence of nickel or arsenite during the recovery incubation retarded the disappearance of UV-induced strand breaks, whereas the disappearance of MMS-induced strand breaks was retarded by the presence of arsenite or of luminol, a new inhibitor for poly(ADP-ribose) synthetase. Luminol, however, had no apparent effect on the repair of UV-induced DNA strand breaks, and nickel had no effect on the repair of MMS-induced DNA strand breaks. When UV- or MMS-treated cells were incubated in cytosine arabinofuranoside (AraC) plus hydroxyurea (HU), a large amount of low molecular weight DNA was detected by alkaline sucrose sedimentation. The molecular weight of these DNAs increased if the cells were further incubated in a drug-free medium. This rejoining of breaks in cells pretreated with UV plus AraC and HU was inhibited by nickel and by arsenite, but not by luminol. The rejoining of breaks in cells pretreated with MMS plus AraC and HU was inhibited by luminol and by arsenite, but not by nickel. These results suggest that different enzymes may be used in DNA resynthesis and/or ligation during the repairing of UV- and MMS-induced DNA strand breaks, and that nickel, luminol, and arsenite may have differential inhibitory effects on these enzymes. © 1994 Wiley-Liss, Inc. 相似文献
998.
Larry E. Davis Mario Kornfeld Herbert S. Mooney Kurt J. Fiedler Kathleen Y. Haaland William W. Orrison Elsa Cernichiari Thomas W. Clarkson 《Annals of neurology》1994,35(6):680-688
For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and atentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retradation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage. 相似文献
999.
A review of data on 360 patients with esophageal squamous cell carcinoma who underwent esophageal resection revealed 14 cases (3.9%) and 16 lesions with synchronous gastric carcinomas. Among the 16 lesions, there were 14 (87.5%) early gastric carcinomas and two advanced carcinomas. Of the 14 early gastric carcinomas, two were minute (less than 5 mm in the largest diameter) early gastric carcinomas and four small (6-10 mm in the largest diameter). These gastric carcinomas were in a relatively early stage. The six early gastric carcinomas were not detected preoperatively. However, a thorough observation of the gastric mucosa could not be done in four of those due to stenosis which had developed as a result of the esophageal carcinoma. Therefore, intraoperative gastric observation should be done in cases in which the findings of the preoperative endoscopic examination of the stomach are inadequate and the upper gastrointestinal series reveal certain gastric abnormalities. 相似文献
1000.
We investigated populations of the infiltrating cells in Bowen's disease (BD) and squamous cell carcinoma (SCC), both of which arose in the same patient, using the Avidin-Biotin-peroxidase complex method with eight monoclonal antibodies. T lymphocytes were most predominant among infiltrating cells; NK cells, B cells, and monocytes were rarely seen in either BD or SCC. Analysis of subsets of the infiltrating T lymphocytes revealed that the number of suppressor/cytotoxic (s/c) T cells was twice that of helper/inducer (h/i) T cells in BD, while the number of s/c T cells was lower than that of h/i T cells in SCC. The immunohistochemical results in the present case differed from those of predominant infiltration of h/i T cells and of s/c T cells in three other reports of BD and SCC. These results suggest that the population of the cellular infiltrates may be modulated by the nature of tumors and by the immuno-competent state of the hosts. 相似文献