全文获取类型
收费全文 | 711篇 |
免费 | 71篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 26篇 |
妇产科学 | 7篇 |
基础医学 | 128篇 |
口腔科学 | 13篇 |
临床医学 | 66篇 |
内科学 | 129篇 |
皮肤病学 | 60篇 |
神经病学 | 25篇 |
特种医学 | 48篇 |
外科学 | 60篇 |
综合类 | 25篇 |
预防医学 | 42篇 |
眼科学 | 8篇 |
药学 | 80篇 |
中国医学 | 1篇 |
肿瘤学 | 66篇 |
出版年
2021年 | 9篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 15篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 28篇 |
2013年 | 39篇 |
2012年 | 28篇 |
2011年 | 19篇 |
2010年 | 27篇 |
2009年 | 32篇 |
2008年 | 27篇 |
2007年 | 31篇 |
2006年 | 30篇 |
2005年 | 30篇 |
2004年 | 29篇 |
2003年 | 22篇 |
2002年 | 29篇 |
2001年 | 21篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 29篇 |
1997年 | 22篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1994年 | 14篇 |
1993年 | 25篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1871年 | 2篇 |
排序方式: 共有795条查询结果,搜索用时 78 毫秒
1.
2.
3.
4.
神经生长因子对小鼠突触体内Ca^2+水平的调节作用 总被引:4,自引:1,他引:3
观察了多次海马内微注射NGF对小鼠突触体内游离钙水平的影响,并在离体情况下观察NGF对EGTA和CaCl2分别造成突触体内低钙和高钙状态的调节作用。结果如下:(1)在体实验表明,一定剂量的NGF可显著降低老年小鼠海马突触体内游离钙水平(P<005);(2)离体实验表明,当突触体游离钙水平降低时,适当剂量的NGF具有升高游离钙水平的作用;而突触体内游离钙水平升高时,则NGF有降低游离钙水平的作用。提示NGF对游离钙水平的双向调节作用可能是NGF改善老年性记忆衰退的作用机制。 相似文献
5.
Evans A. M. Nation R. L. Sansom L. N. Bochner F. Somogyi A. A. 《European journal of clinical pharmacology》1989,36(3):283-290
Summary We have developed a novel and reproducible method for determining the plasma protein binding of the two ibuprofen enantiomers in the presence of each other. The method involves the use of radiolabelled racemic ibuprofen, equilibrium dialysis, derivatization of the enantiomers to diastereomeric amides, high-performance liquid chromatography, and radiochemical analysis.We have determined the plasma protein binding of R(–)- and S(+)-ibuprofen in 6 healthy male volunteers after the oral administration of 800 mg racemic ibuprofen.The mean time-averaged percentage unbound of the R(–)-enantiomer, 0.419 was significantly less than that of the S(+)-enantiomer, 0.643, consistent with stereoselective plasma protein binding.The percentage unbound of each ibuprofen enantiomer was concentration-dependent over the therapeutic concentration range and was influenced by the presence of its optical antipode. 相似文献
6.
P J Wood I J Stratford J M Sansom B M Cattanach R M Quinney G E Adams 《International journal of radiation oncology, biology, physics》1992,22(3):473-476
31P magnetic resonance spectroscopy has been used to compare the effects of the vasoactive agents hydralazine and flunarizine on the oxygenation of the transplantable tumors, SCCVII/Ha and 16C, and a range of spontaneous mammary tumors arising in the breeding stock in the Genetics Division at the Radiobiology Unit. The vasodilator hydralazine, previously shown to increase the radiobiological hypoxic fraction of transplantable murine tumors, increased inorganic phosphate to total phosphate (Pi/total) in SCCVII/Ha and 16C tumors. However, only two spontaneous tumors responded to this agent (2/12). The calcium antagonist flunarizine, which sensitizes the SCCVII tumor to X rays, consistent with a reduction in hypoxic fraction, reduced Pi/total in this and the 16C tumor. Further, most spontaneous tumors tested (8/10) responded to this agent, as measured by a reduction in Pi/total. These results point to fundamental differences between transplantable and spontaneously arising tumors in mice in their response to vasoactive agents. 相似文献
7.
Delayed reaction to bed bug bites. 总被引:2,自引:0,他引:2
8.
Abstract Background: Many residents of aged-care accommodation are chronic users of benzodiazepines. This pattern of use contradicts current guidelines and may adversely affect residents. It was hypothesised that a lasting reduction in benzodiazepine use could be achieved through a programme which involved prescribers, residents and caregivers in the change process. Aim: To demonstrate that an intervention which involved education and relaxation training for patients, and education of prescribers and caregivers, could reduce levels of chronic benzodiazepine use among residents of an aged-care facility. Methods: Two aged-care facilities from metropolitan Adelaide were chosen; one received the intervention, the other was a no-intervention comparison. Pre-test, post-test and follow-up interviews were conducted with 60 residents: 27 from the intervention setting and 33 from the comparison setting. Residents at the intervention setting were provided with relaxation skills training, and their medical practitioners and caregivers were provided with information about alternative strategies for managing sleep disturbance. Outcome measures were: the proportion of residents using benzodiazepines, total medication use, cognitive performance, emotional responsiveness, subjective health and sleep ratings and an index of well-being. Results: The proportion of participants in the intervention condition who used benzodiazepines declined significantly (from 70% to 35%); the reduction was maintained over the subsequent three months. No adverse consequences were associated with cessation of benzodiazepine use; there was improvement in emotional responsiveness among those who ceased benzodiazepine use. This structured intervention strategy is a useful approach for reducing levels of chronic benzodiazepine use among residents of aged-care accommodation. 相似文献
9.
MY Mancao LJ Sindel PH Richardson FM Silver 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(1):118-120
Croup is an acute infectious illness usually occurring in children; it is characterized by brassy cough and stridor. The main pathogens include mainly parainfluenza and influenza viruses. Recently there have been reports of prolonged croup caused by the herpes simplex viruses. We report two cases of prolonged croup due to herpes simplex types 1 and 2. We also review and summarize the reported pediatric cases of herpetic croup. 相似文献
10.
Duncan WC; Illingworth PJ; Young FM; Fraser HM 《Human reproduction (Oxford, England)》1998,13(9):2532-2540
The molecular mechanisms involved in luteolysis are still unclear in the
primate. This study aimed to investigate the effect of induced luteolysis
on the ovarian luteinizing hormone (LH) receptor and the steroidogenic
enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset
monkey. Luteolysis was induced in the mid-luteal phase either directly by
systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal
using systemic gonadotrophin releasing hormone antagonist (GnRHant)
treatment. The LH receptor was studied by isotopic mRNA in-situ
hybridization and in-situ ligand binding and 3beta-HSD expression was
studied using isotopic mRNA in-situ hybridization and immunohistochemistry.
Induced luteolysis was associated with a reduction in the expression of LH
receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a
reduction in the LH receptor (P < 0.05) and 3beta-HSD protein
concentrations within 24 h. There were no differences in the findings
whether luteolysis was induced with PGF2alpha or GnRHant. This study shows
that disparate mechanisms to induce luteolysis in the primate result in an
identical rapid loss of the LH receptor and 3beta-HSD. In conclusion,
induced luteolysis leads to rapid loss of the steroidogenic pathway in
luteal cells.
相似文献