全文获取类型
收费全文 | 1361篇 |
免费 | 117篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 76篇 |
妇产科学 | 15篇 |
基础医学 | 154篇 |
口腔科学 | 53篇 |
临床医学 | 152篇 |
内科学 | 372篇 |
皮肤病学 | 4篇 |
神经病学 | 71篇 |
特种医学 | 139篇 |
外科学 | 106篇 |
综合类 | 83篇 |
预防医学 | 78篇 |
眼科学 | 21篇 |
药学 | 65篇 |
中国医学 | 1篇 |
肿瘤学 | 96篇 |
出版年
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 26篇 |
2014年 | 30篇 |
2013年 | 62篇 |
2012年 | 47篇 |
2011年 | 42篇 |
2010年 | 52篇 |
2009年 | 38篇 |
2008年 | 48篇 |
2007年 | 69篇 |
2006年 | 61篇 |
2005年 | 36篇 |
2004年 | 41篇 |
2003年 | 48篇 |
2002年 | 44篇 |
2001年 | 61篇 |
2000年 | 46篇 |
1999年 | 47篇 |
1998年 | 40篇 |
1997年 | 35篇 |
1996年 | 34篇 |
1995年 | 25篇 |
1994年 | 28篇 |
1993年 | 27篇 |
1992年 | 26篇 |
1991年 | 31篇 |
1990年 | 24篇 |
1989年 | 42篇 |
1988年 | 37篇 |
1987年 | 21篇 |
1986年 | 23篇 |
1985年 | 30篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1966年 | 8篇 |
排序方式: 共有1494条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
Bone is a frequent site of tumour metastasis and is the third most common site of metastatic carcinoma. With advances in the use of immunotherapy, hormonal manipulation, chemotherapy and radiation for the palliation of patients with metastatic bone disease, significant improvements in survival, wellbeing and overall quality of life have been achieved. 相似文献
65.
A child with pseudoxanthoma elasticum had mitral valvar prolapse with severe regurgitation necessitating replacement with a prosthetic valve. Extensive formation of pannus caused obstruction of two mechanical valves, one after twenty months and the second after three years. Histology of the pannus was similar to the endocardial lesions that are considered unique to pseudoxanthoma elasticum. 相似文献
66.
Radford IR 《International journal of radiation biology》2002,78(6):457-466
PURPOSE: To determine whether murine lymphoid cell lines can discriminate between high- and low-LET (linear energy transfer) radiation-induced DNA lesions. MATERIALS AND METHODS: Sensitivity to killing by DNA-incorporated 3H and 125I decays, accumulated during storage in the gas phase of a liquid nitrogen tank, was determined by clonogenic survival assay. RESULTS: Induction of a lethal event in the STRij-4-2.2, WEHI-22.1, and L5178Y-R cell lines required approximately 30 times more 3H than 125I decays. Hence, the same ratio of 3H to 125I decays was found irrespective of whether the cell lines contained mutant or wild-type p53 and irrespective of whether they underwent rapid interphase or mitosis-related apoptosis after irradiation. The 18-81 cell line differed in showing a ratio of around 21 and it is argued that this may be a consequence of v-ABL over-expression. The assumption that DNA-incorporated 3H and 125I decays are low- and high-LET-like events respectively was confirmed by the similar sensitivity of L5178Y-R and -S cells to killing by 125I decays in contrast with their difference in sensitivity to 3H decays. CONCLUSIONS: The difference in lethal effectiveness between DNA-incorporated 3H and 125I decays can be explained by the hypothesis that simple DSB (double-strand breaks) are non-lethal and that cell killing is attributable to complex DSB. The low-LET radiation-specific sensitization of L5178Y-S cells may reflect defective repair of a DNA lesion class (presumably simple DSB) that is differentially induced by high- and low-LET radiation and is non-lethal to cells with normal repair capacity. 相似文献
67.
Radford IR 《International journal of radiation biology》2002,78(6):467-474
PURPOSE: To present a model for the molecular events that lead to the induction of apoptosis in irradiated lymphoid cells based on the assumption that the process is triggered by complex DNA double-strand breaks (DSB). OUTLINE OF THE MODEL: * Cellular DNA repair mechanisms have difficulty rejoining complex DSB because of the nature of the end groups on such breaks. * Association between p53 and DNA topoisomerase I (topo I) can occur at complex DSB in open regions of the genome and the enzymic activity of such associations is not suppressed by polyADP-ribosylation. * Binding of p53 and topo I at a complex DSB results in the transient trapping of a DNA-topo I cleavage complex. * Transiently trapped DNA-topo I cleavage complexes at complex DSB are reversed following association with topo I bound elsewhere in the genome, thus initiating a misrejoining event. * Topo I-mediated DNA misrejoining creates a structure that activates p53. Initiation of rapid interphase apoptosis requires that the inducing signal from activated p53 exceeds a threshold level. * Initiation of rapid interphase apoptosis is regulated by poly(ADP-ribose) polymerase. 相似文献
68.
A J M Ferreri M Ponzoni G P Dognini M-Q Du C Doglioni J Radford R Dolcetti F Cavalli 《Annals of oncology》2006,17(11):1721-1722
We read with great interest the article by Grünberger etal. on the blind administration of doxycyclinein a retrospective series of 11 patients with ocular adnexallymphoma of MALT-type (OAL) [1]. Authors used this therapy onthe basis that, in the Italian experience [2], most cases ofOAL were shown to be related to chlamydial 相似文献
69.
Quality of medical care and excess mortality in older patients with mental disorders 总被引:16,自引:0,他引:16
Druss BG Bradford WD Rosenheck RA Radford MJ Krumholz HM 《Archives of general psychiatry》2001,58(6):565-572
BACKGROUND: This study investigated whether differences in quality of medical care might explain a portion of the excess mortality associated with mental disorders in the year after myocardial infarction. METHODS: This study examined a national cohort of 88 241 Medicare patients 65 years and older who were hospitalized for clinically confirmed acute myocardial infarction. Proportional hazard models compared the association between mental disorders and mortality before and after adjusting 5 established quality indicators: reperfusion, aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, and smoking cessation counseling. All models adjusted for eligibility for each procedure, demographic characteristics, cardiac risk factors and history, admission characteristics, left ventricular function, hospital characteristics, and regional factors. RESULTS: After adjusting for the potential confounding factors, presence of any mental disorder was associated with a 19% increase in 1-year risk of mortality (hazard ratios [HR], 1.19; 95% confidence interval [CI], 1.04-1.36). After adding the 5 quality measures to the model, the association was no longer significant (HR, 1.10; 95% CI, 0.96-1.26). Similarly, while schizophrenia (HR, 1.34; 95% CI, 1.01-1.67) and major affective disorders (HR, 1.11; 95% CI, 1.02-1.20) were each initially associated with increased mortality, after adding the quality variables, neither schizophrenia (HR, 1.23; 95% CI, 0.86-1.60) nor major affective disorder (HR, 1.05; 95% CI, 0.87-1.23) remained a significant predictor. CONCLUSIONS: Deficits in quality of medical care seemed to explain a substantial portion of the excess mortality experienced by patients with mental disorders after myocardial infarction. The study suggests the potential importance of improving these patients' medical care as a step toward reducing their excess mortality. 相似文献
70.
Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis 总被引:2,自引:0,他引:2
KJ Rademaker F Groeneadaal GH Jansen P Eken LS De Vries 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(6):602-608
Rademaker KJ, Groenendaal F, Jansen GH, Eken P, de Vries LS. Unilateral haemorrhagic parenchymal lesions in the preterm infant: shape, site and prognosis. Acta Pædiatr 1994;83:602–8. Stockholm. ISSN 0803–5253 In a prospective cranial ultrasound study of 544 infants with a gestational age of 32 weeks or less, 20 (3.6%) infants were diagnosed as having a unilateral parenchymal lesion (PL). Based on the shape of the PL and the evolution on ultrasound, the infants were divided into three groups: group I consisted of 11 infants, in whom the PL was triangular/fan-shaped and separate from the ventricle. The PL evolved into small cystic lesions; group II comprised 3 infants who had a PL with a similar shape, but partially communicating with the ventricle; group III consisted of 6 infants who had a globular-shaped lesion in communication with the ventricle. In groups II and III, the PL evolved into one porcncephalic cyst. The PL was considered to be due to venous infarction in all cases with intraventricular haemorrhage preceding the PL in 7 cases. Sixteen infants survived. A postmortem was performed in 2 of the 4 infants who died, confirming the diagnosis of venous infarction. Neurologicdl sequelae were present in only 2 cases in the first group, while all 6 survivors of the other two groups developed mild to severe hemiplegia. Long-term follow-up was not always available and 4 of the 18 survivors were still less than 18 months when last seen. In 9 of the 11 infants in group I, the PL was localized in the frontoparietal region, while in 8 of the 9 infants in group II or III, the PL was beyond the trigone in the occipital region. The outcome of the unilateral PL is not always unfavourable. It was evident that not only the shape of the lesion and whether or not there was communication with the lateral ventricle, but also the site of the lesion (whether or not it extended into the occipital periventricular white matter) appeared to be important with regard to neurodevelopmental outcome. 相似文献