全文获取类型
收费全文 | 952篇 |
免费 | 144篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 93篇 |
妇产科学 | 15篇 |
基础医学 | 92篇 |
口腔科学 | 39篇 |
临床医学 | 146篇 |
内科学 | 218篇 |
皮肤病学 | 9篇 |
神经病学 | 38篇 |
特种医学 | 162篇 |
外科学 | 127篇 |
综合类 | 35篇 |
预防医学 | 41篇 |
眼科学 | 1篇 |
药学 | 22篇 |
中国医学 | 5篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 35篇 |
2017年 | 42篇 |
2016年 | 37篇 |
2015年 | 34篇 |
2014年 | 37篇 |
2013年 | 63篇 |
2012年 | 30篇 |
2011年 | 24篇 |
2010年 | 60篇 |
2009年 | 53篇 |
2008年 | 30篇 |
2007年 | 29篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 18篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 59篇 |
1997年 | 53篇 |
1996年 | 55篇 |
1995年 | 49篇 |
1994年 | 28篇 |
1993年 | 40篇 |
1992年 | 16篇 |
1991年 | 19篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 24篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 3篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1978年 | 2篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1968年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有1106条查询结果,搜索用时 15 毫秒
91.
R Skelton P Holland M Darowski PA Chetcuti LW Morgan JL Harwood 《Acta paediatrica (Oslo, Norway : 1992)》1999,88(9):942-946
A prospective study of infants under 1 y of age, ventilated for severe viral bronchiolitis, was carried out in four paediatric intensive care units in order to study surfactant activity and composition in this condition. Lung lavage fluid from 24 infants with bronchiolitis, 19 with bronchiolitis and sepsis or cardiac failure and 12 controls were analysed by the “click test” for surfactant activity and for phospholipids. Surfactant activity was present in all controls, but in only 2 of the 24 infants with bronchiolitis alone. The presence of phosphatidylglycerol correlated perfectly with the click test, suggesting that reduced activity is due to changes in surfactant lipid composition. In those with bronchiolitis plus coexisting disease, surfactant activity and phosphatidylglycerol were absent in only half. Surfactant activity and phosphatidylglycerol re-appeared by extubation. Severe viral bronchiolitis is associated with an absence of surfactant activity and PG, which resolves by clinical recovery. Infants with coexisting conditions are not always surfactant deficient. Surfactant administration is likely to be beneficial, but requires a selective approach. 相似文献
92.
Jennifer G. Goldman MD Christopher G. Goetz MD Melanie Brandabur MD Michelle Sanfilippo MPAS PA‐C Glenn T. Stebbins PhD 《Movement disorders》2008,23(15):2248-2250
Dopaminergic treatment in dementia with Lewy bodies (DLB) requires balancing risk of worsened psychosis and potential motor benefit. We assessed the effects of increased dopaminergic medication on psychosis and motor function in DLB. We studied 19 subjects fulfilling probable DLB Consensus criteria before and after increased dopaminergic medications. Standard clinical measures included: Thought Disorder score from the Unified Parkinson's disease Rating Scale (UPDRS) Part I, total motor score (UPDRS Part III), and Hoehn–Yahr (H&Y) stage. Motor benefit defined as >10% improvement over baseline UPDRS Part III score, occurred in only one‐third of subjects. In this group, worsened hallucinations or psychosis developed in one‐third. Considering motor benefit without exacerbation of psychosis as our aim, only 4 DLB subjects (22%) achieved this goal. Our results suggest that dopaminergic medications have limited benefit in DLB because of the low likelihood of motor improvement and the risk of psychosis exacerbation. © 2008 Movement Disorder Society 相似文献
93.
Nicholas C Stefanis Thomas A Trikalinos Dimitrios Avramopoulos Nikos Smyrnis Ioannis Evdokimidis Evangelia E Ntzani Alex Hatzimanolis John PA Ioannidis Costas N Stefanis 《Behavioral and brain functions : BBF》2008,4(1):46
Background
While association studies on schizophrenia show conflicting results regarding the importance of the regulator of the G-protein signaling 4 (RGS4) gene, recent work suggests that RGS4 may impact on the structural and functional integrity of the prefrontal cortex. We aimed to study associations of common RGS4 variants with prefrontal dependent cognitive performance and schizotypy endophenotypes at the population level. 相似文献94.
Magnetic resonance (MR) imaging was performed on 14 patients with histologically proved osteosarcoma (mean age, 14.4 years). There was excellent correlation of intramedullary tumor extent as determined with MR imaging and pathologic examination (r = 99%). This was facilitated by the presence of a chemical shift artifact at the tumor-marrow interface on the T1-weighted images. The correlation between CT and pathologic findings was not as good (r = 84%). In a single patient, however, a 10-cm length of sclerotic bone was incorrectly interpreted as being tumor. If this case is excluded, the correlation between CT and pathologic findings improves significantly (r = 96%). T2-weighted images were optimal in demonstrating soft-tissue bulk and breach of the epiphysis or cortex. Vascular involvement was also readily defined. The T2 value of the tumor soft-tissue component decreased in patients who were deemed to have responded well to therapy. Two patients with very high T2 values after chemotherapy developed wide-spread metastatic disease and died. Phosphorus-31 MR spectroscopy of five patients with osteosarcoma showed elevated levels of phosphomonoesters (PMEs), inorganic phosphate (Pi), and phosphodiesters (PDEs). PME and PDE peak areas decreased in three patients after chemotherapy, while Pi peak areas increased. 相似文献
95.
Carotid artery: percutaneous transbrachial selective arteriography with a 4-F catheter 总被引:1,自引:0,他引:1
Bilateral selective common carotid artery catheterization was attempted in 72 patients by means of percutaneous placement of a 4-F catheter from a right brachial artery puncture site in the antecubital fossa. The success rate was high (95.8%) and the complication rate low (6.9%), and there were no instances of brachial artery spasm or thrombosis. The experience, while small, suggests that selective common carotid arteriography can be done safely and efficaciously from the right brachial artery approach. 相似文献
96.
97.
Migraine-associated vertigo 总被引:2,自引:0,他引:2
PA Savundra JD Carroll RA Davies LM Luxon 《Cephalalgia : an international journal of headache》1997,17(4):505-510
A retrospective analysis was performed on consecutive series of 363 patients presenting with vertigo; 32% had migraine. Of the 224 patients with no pathology other than migraine or vestibular dysfunction, migraineurs had a significantly higher prevalence of normal, central, and combined central and peripheral vestibular dysfunction compared to non-migraineurs. The combination of central and peripheral vestibular signs was a feature of migraine with aura. The results support the hypothesis that migraine-associated vertigo is a diagnostic entity. 相似文献
98.
Isolation and characterization of murine cell surface components. I. Purification of milligram quantities of Thy-1.1 总被引:1,自引:0,他引:1 下载免费PDF全文
The Thy-l.1 molecule was isolated from the BW5147 murine lymphoblastoid cell line. The initial step in purification was the preparation of a crude plasma membrane fraction followed by acetone precipitation. The acetone pellet was solubilized using deoxycholate (DOC) and Thy-1.1 was purified by use of a Lens culinaris lectin affinity column and an AcA-34 gel filtration column. The purified glycoprotein with Thy-1.1 activity had a mol wt of approximately 25,000 daltons. The isolation of this molecule was effected by detecting Thy-I activity utilizing rabbit anti- mouse brain serum tested on rat thymocytes. Congenic anti-Thy-l.1 serum was ineffective in detecting Thy-l.1 after DOC solubilization. An antiserum prepared in rabbits to the purified Thy-1.1 was found to be cytotoxic to mouse and rat thymocytes. The cytotoxic activity of this antisera could be completely absorbed with AKR/Jax brain and thymus but was not absorbed by liver. In addition, AKR/Jax thymocytes totally absorbed all cytotoxic activity of the rabbit anti-purified Thy-1 serum for BW5147 cells suggesting that the cell line shares identical specificities with normal thymocytes. The purified Thy-1.1 molecule was able to totally absorb the cytotoxic activity of mouse congenic anti-Thy-1. These studies serve as a model for the isolation of other murine lymphoid cell surface components in quantities for detailed structural and functional analysis. 相似文献
99.
100.
Autologous blood donors (ABDs) have been reported to have favorable attitudes toward returning as homologous blood donors (HBDs), but the frequency of return has not been well documented. ABDs eligible by history to be HBDs were followed at one blood center: 255 donating for elective surgery and 234 donating during pregnancy were followed for an average of 18 months and 20 months, respectively, from time of eligibility after surgery or postpartum. Male ABDs had a higher rate of return as HBDs, as 34 percent (21/62) returned to donate an average of 3 units, whereas 13 percent (56/427) of female ABDs returned as HBDs to donate an average of 2 units. Although a history of donation was associated with a higher rate of return (30%, 34/113), 11 percent (43/376) of ABDs with no history as HBDs returned to donate homologous units, despite having been recruited less frequently than prior HBDs. Overall, all male ABDs and female ABDs with an HBD history returned most frequently. The extra effort required for an autologous donor program may result in the recruitment of new donors into the HBD pool. 相似文献