全文获取类型
收费全文 | 733969篇 |
免费 | 43792篇 |
国内免费 | 992篇 |
专业分类
耳鼻咽喉 | 9786篇 |
儿科学 | 23451篇 |
妇产科学 | 18033篇 |
基础医学 | 116622篇 |
口腔科学 | 19618篇 |
临床医学 | 61972篇 |
内科学 | 142188篇 |
皮肤病学 | 17944篇 |
神经病学 | 56000篇 |
特种医学 | 25061篇 |
外国民族医学 | 164篇 |
外科学 | 104288篇 |
综合类 | 9401篇 |
一般理论 | 180篇 |
预防医学 | 58709篇 |
眼科学 | 16445篇 |
药学 | 55923篇 |
中国医学 | 1670篇 |
肿瘤学 | 41298篇 |
出版年
2021年 | 6362篇 |
2019年 | 7125篇 |
2018年 | 12000篇 |
2017年 | 8295篇 |
2016年 | 8713篇 |
2015年 | 9729篇 |
2014年 | 11497篇 |
2013年 | 18308篇 |
2012年 | 28247篇 |
2011年 | 29574篇 |
2010年 | 15860篇 |
2009年 | 13407篇 |
2008年 | 26758篇 |
2007年 | 28766篇 |
2006年 | 27806篇 |
2005年 | 27116篇 |
2004年 | 25973篇 |
2003年 | 24317篇 |
2002年 | 23591篇 |
2001年 | 29390篇 |
2000年 | 30477篇 |
1999年 | 25387篇 |
1998年 | 6243篇 |
1997年 | 5379篇 |
1996年 | 5692篇 |
1995年 | 5212篇 |
1992年 | 18580篇 |
1991年 | 18894篇 |
1990年 | 18875篇 |
1989年 | 18044篇 |
1988年 | 16733篇 |
1987年 | 16398篇 |
1986年 | 15469篇 |
1985年 | 14673篇 |
1984年 | 10909篇 |
1983年 | 9311篇 |
1982年 | 5181篇 |
1979年 | 10490篇 |
1978年 | 7628篇 |
1977年 | 6493篇 |
1976年 | 6185篇 |
1975年 | 7131篇 |
1974年 | 8539篇 |
1973年 | 8047篇 |
1972年 | 7805篇 |
1971年 | 7526篇 |
1970年 | 6969篇 |
1969年 | 6712篇 |
1968年 | 6260篇 |
1967年 | 5616篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Decreased expression of DMPK: correlation with CTG repeat expansion and fibre type composition in myotonic dystrophy type 1 总被引:2,自引:0,他引:2
S. Salvatori M. Fanin C. P. Trevisan S. Furlan S. Reddy J. I. Nagy C. Angelini 《Neurological sciences》2005,26(4):235-242
Abstract Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a trinucleotide repeatexpansion, cytosine-thymine-guanine
(CTG)n, in the 3′ untranslated region of a gene encoding the myotonic dystrophy protein kinase (DMPK). To correlate CTG expansion
and protein expression, we studied muscle specimens from 16 adult DM1 patients using three anti-DMPK antibodies for immunoblotting.
We estimated the amount of the full-length DMPK (85 kDa) in muscle biopsies from normal controls and from DM1 patients carrying
different (CTG)n expansions. We found that DMPK concentration was decreased to about 50% in DM patients’ muscles; the protein decrease did
not seem correlated with the CTG repeat length. However, the fibre type composition in skeletal muscle seemed somehow to affect
DMPK decrease, as the lowest level of the enzyme was found in patients with the lowest content of type 1 fibre. 相似文献
992.
B Fouquet I Griffoul M J Borie R Roger B Bonnin J C Metivier S Pellieux 《Annales de Réadaptation et de Médecine Physique》2006,49(2):68-74
INTRODUCTION: Adhesive capsulitis is a clinical entity characterized by a loss of motion and a decrease of the joint volume capacity. Results of clinical trials have shown that distensions can help to decrease pain and increase the range of motion. OBJECTIVE: The purpose of the study was to measure the effect of repeated distension arthrography combined with an intensive program of rehabilitation on pain, range of motion, and occupational outcome in patients with adhesive capsulitis. DESIGN: 39 cases of idiopathic capsulitis (7 cases) or secondary capsulitis (19 post-traumatic, 13 post-surgery of the rotator cuff) were included in the study. Intervention consisted of an intensive program of passive and active physiotherapy during one? Week and then distension arthrography, performed 3 times at 1- week intervals, with steroid injections in the glenohumeral joint and 1 in the subacromial space. RESULTS: Lateral elevation improved substantially after the first week of physiotherapy and medial rotation after the first distension. Pain intensity decreased after the first distension. After the third distension, very small changes were noted. Results did not differ by etiology of capsulitis. At the end of the program, 9 of 17 patients could return to their previous job. CONCLUSIONS: Two repeated arthrographic distensions with steroid injection and an intensive program of physiotherapy improves the range of motion and the painful condition associated with capsulitis and allows for a rapid return to employment. A third distension does not seem to provide a further benefit, as has been found by other studies. 相似文献
993.
994.
995.
The aim of this study was to evaluate whether a prevalent vertebral deformity predicts mortality and fractures in both men and women. In the city of Malmö, 598 individuals (298 men, 300 women; age 50–80 years) were selected from the city's population and were included in the Swedish part of the European Vertebral Osteoporosis Study (EVOS). At baseline the participants answered a questionnaire and lateral spine radiographs were performed. The prevalence of subjects with vertebral deformity was assessed using a morphometric method. The mortality during a 10-year follow-up period was determined through the register of the National Swedish Board of Health and Welfare. Eighty-five men and 43 women died during the study period. The subsequent fracture incidence during the follow-up period was ascertained by postal questionnaires, telephone interviews and by a survey of the archives of the Department of Radiology in the city hospital. Thirty-seven men and 69 women sustained a fracture during the study period. Data are presented as hazard ratios (HR) with 95% confidence interval (95% CI) within brackets. Prevalent vertebral deformity, defined as a reduction by more than 3 standard deviations (SD) in vertebral height ratio, predicted mortality during the forthcoming decade in both men [age-adjusted HR 2.4 (95% CI 1.6–3.9)] and women [age-adjusted HR 2.3 (95% CI 1.3–4.3)]. In men there was an increased mortality due to cardiovascular and pulmonary diseases and in women due to cancer. Prevalent vertebral deformity predicted an increased risk of any fracture during the forthcoming decade in both men [age-adjusted HR 2.7 (95% CI 1.4–5.3)] and women [age-adjusted HR 1.8 (95% CI 1.1–2.9)]. Prevalent vertebral deformity predicted an increased risk of any subsequent fragility fracture in women [age-adjusted HR 2.0 (95% CI 1.1–3.5)]; however, in men the increased risk was nonsignificant [age-adjusted HR 1.9 (95% CI 0.7–5.1)]. In summary, a prevalent vertebral deformity can predict both increased mortality and increased fracture incidence during the following decade in both men and women. We conclude that prevalent vertebral deformity could be used as a risk factor in both genders for mortality and future fracture. 相似文献
996.
A sexually dimorphic ratio of orbitofrontal to amygdala volume is altered in schizophrenia. 总被引:3,自引:0,他引:3
Raquel E Gur Christian Kohler Bruce I Turetsky Steven J Siegel Stephen J Kanes Warren B Bilker Avis R Brennan Ruben C Gur 《Neuropsychopharmacology》2004,55(5):512-517
BACKGROUND: Neuroanatomic sexual dimorphisms have been correlated with behavioral differences between healthy men and women. We have reported higher orbitofrontal cortex to amygdala ratio (OAR) in women than men. Although gender differences in schizophrenia are evident clinically and correlate with neuroanatomic measures, their relationship to OAR has not been examined. METHODS: Magnetic resonance imaging was performed in 31 neuroleptic-na?ve schizophrenic patients (16 men) and 80 healthy volunteers (34 men), aged less than 50 years. An automated tissue segmentation procedure was combined with expert-guided parcellation of orbitofrontal and amygdala volumes. RESULTS: Men with schizophrenia had increased OAR relative to healthy men, whereas women had decreased OAR. Increased OAR in men with schizophrenia reflected abnormally low amygdala volumes, whereas decreased OAR in women reflected abnormally low orbitofrontal volumes. Less severe negative symptoms were associated with increased OAR in men but with decreased OAR in women. In men, increased amygdala volume was associated with greater symptom severity, whereas in women higher volumes of both amygdala and orbitofrontal regions were associated with lesser severity of negative symptoms. CONCLUSIONS: These opposite OAR abnormalities, whereby men show feminization and women masculinization, suggest gender-mediated effects of the underlying neuropathologic processes. The correlations with symptom severity suggest that neuroanatomic abnormalities in OAR reflect compensatory brain changes. 相似文献
997.
Solubility of enamel powder following treatments with 1% sodium dodecyl sulphate in the presence and absence of fluoride 总被引:1,自引:0,他引:1
Deionized water exerts a solubility effect on enamel which is increased in the presence of sodium dodecyl sulphate (SDS), at a concentration used in dentifrices. As expected, incorporation of fluoride by enamel decreases the solubility effect of the detergent in water and acidic buffer. With duration of treatment, the detergent has a lesser effect than demineralized water alone on subsequent solubility of enamel in acidic buffer. 相似文献
998.
999.
Bile acid receptors in colorectal cancer 总被引:4,自引:0,他引:4
Bile acids are thought to be involved in both the aetiology and development of colorectal cancer. In this study the existence of specific bile acid receptor proteins has been postulated. A receptor assay which involved labelling with 14C-deoxycholic acid was performed as well as autoradiography using 3H-deoxycholic acid. In an initial study resected colorectal cancer and adjacent histologically normal colorectal mucosa from 39 patients were studied, as were samples of normal gastric mucosa, cancers and benign colorectal tumours. Specific receptors to deoxycholic acid were detected in 12 (30.8 per cent) of the colorectal cancers, but in only 1 (2.6 per cent) of the samples from normal colorectal mucosa (X2 = 11.16, P less than 0.005). No deoxycholic acid receptors were detected in any other tissue studied. Autoradiographs of colorectal cancers showed binding of 3H-deoxycholic acid in receptor-positive tumour tissue. These findings might provide some explanation for the evidence linking bile acids with the disease. 相似文献
1000.
Histological, histochemical and electron microscopic changes of the placenta induced by maternal exposure to hyperthermia in the rat. 总被引:3,自引:0,他引:3
R Padmanabhan N M Al-Menhali I Ahmed H H Kataya M A Ayoub 《International journal of hyperthermia》2005,21(1):29-44
Both clinical and experimental investigations have shown that maternal hyperthermia during critical stages of embryo development can induce malformations in the offspring. Studies of the effect of heat stress on the placental functions are limited to the ewes, but that on microscopic structure is unknown. In the present study, rats were exposed to 41 or 42 degrees C for 1 h on gestation day (GD) 9. The controls were sham treated. Fetuses and placentas were collected on GD 20. Intrauterine growth retardation (IUGR) and several craniofacial malformations were observed in the fetuses of the heat-treated group. The placentas of the 42 degrees C group were significantly lighter in weight than those of the control. Light microscopy (LM) revealed thickening, hyalinization and occasional lymphocytic infiltration of the decidua basalis. Giant cells were prominent and glycogen cells had degenerated, leaving behind large cysts in the basal (spongy) zone. Best's carmine stain with or without diastase indicated the reduction in number and degeneration of glycogen cells and cyst formation. The labyrinthine zone was relatively thin in comparison to that of the controls. Perivascular fibrosis and paucity of vascularization were other features of the placentas of the hyperthermia group. Electron microscopy (EM) revealed lipid droplet accumulation in the trophoblast, the presence of myelin bodies and an increased production of collagen in the basal zone. Perivascular fibrosis appeared to have contributed to placental barrier thickening. EM also revealed accumulation of glycogen and lipid droplets in the trophoblasts and fibrin secretion into the extracellular space of the labyrinthine zone. These data suggest that placental pathology possibly contributes to fetal growth retardation in maternally heat-stressed rat fetuses. 相似文献