全文获取类型
收费全文 | 14140篇 |
免费 | 1157篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 551篇 |
妇产科学 | 338篇 |
基础医学 | 1782篇 |
口腔科学 | 225篇 |
临床医学 | 1573篇 |
内科学 | 2785篇 |
皮肤病学 | 445篇 |
神经病学 | 1353篇 |
特种医学 | 478篇 |
外科学 | 1841篇 |
综合类 | 355篇 |
一般理论 | 7篇 |
预防医学 | 1205篇 |
眼科学 | 256篇 |
药学 | 818篇 |
中国医学 | 4篇 |
肿瘤学 | 1245篇 |
出版年
2021年 | 162篇 |
2020年 | 106篇 |
2019年 | 181篇 |
2018年 | 214篇 |
2017年 | 160篇 |
2016年 | 178篇 |
2015年 | 194篇 |
2014年 | 269篇 |
2013年 | 413篇 |
2012年 | 565篇 |
2011年 | 631篇 |
2010年 | 328篇 |
2009年 | 347篇 |
2008年 | 583篇 |
2007年 | 614篇 |
2006年 | 590篇 |
2005年 | 608篇 |
2004年 | 542篇 |
2003年 | 504篇 |
2002年 | 505篇 |
2001年 | 483篇 |
2000年 | 509篇 |
1999年 | 430篇 |
1998年 | 181篇 |
1997年 | 168篇 |
1996年 | 117篇 |
1995年 | 130篇 |
1994年 | 124篇 |
1992年 | 363篇 |
1991年 | 352篇 |
1990年 | 366篇 |
1989年 | 349篇 |
1988年 | 267篇 |
1987年 | 299篇 |
1986年 | 307篇 |
1985年 | 307篇 |
1984年 | 203篇 |
1983年 | 229篇 |
1982年 | 124篇 |
1979年 | 202篇 |
1978年 | 140篇 |
1977年 | 124篇 |
1976年 | 139篇 |
1975年 | 134篇 |
1974年 | 144篇 |
1973年 | 136篇 |
1972年 | 107篇 |
1971年 | 101篇 |
1970年 | 119篇 |
1969年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 3 毫秒
51.
52.
53.
Hans Fisher Ph.D. 《Nutrition reviews》1992,50(6):170-171
This study showed that, in chickens, the negative effects of phytate-phosphorus in a low inorganic phosphorus diet could be completely reversed through the additive effects of reduced dietary calcium and increased cholecalciferol. In the future, perhaps greater reliance on more readily available plant phosphorus sources may be instituted in developing countries, where cheap sources of inorganic phosphorus are difficult to obtain. 相似文献
54.
The evolution of paradigms for the management of breast cancer: a personal perspective. 总被引:8,自引:0,他引:8
B Fisher 《Cancer research》1992,52(9):2371-2383
55.
Summary The MCF-7 cell S9 fraction and whole MCF-7 cells can mediate one-electron-redox cycling of doxorubicin, giving rise to concomitant oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH), formation of a drug semiquinone free radical, consumption of molecular oxygen and formation of superoxide anions and hydroxyl radicals. Doxorubicin redox cycling was consistent with DNA strand breakage and cell kill in MCF-7 cells. In contrast, no evidence for redox cycling was found for mitoxantrone (MIT), CI941 or ametantrone (AMET) in MCF-7 cells. Despite the absence of redox cycling, the CI941, MIT, and AMET concentrations resulting in 50% mortality (LC50; 1.5×10–10, 5.2×10–9 and 1.2×10–6
m, respectively) of MCF-7 cells were lower than that of DOX (3.0×10–6
m). Furthermore, the higher cytotoxicity of MIT and CI941 as compared with AMET or DOX was associated with greater efficiency in inducing DNA strand breakage in MCF-7 cells as determined by alkaline elution. Sine MIT and CI941 proved to be the most potent DNA-damaging and cytotoxic agents in this study, the ability of DOX to undergo redox cycling does not appear to confer increased cytotoxic potential on this agent. The present study revealed several important aspects with regards to the structural modification of anthraquinone antitumour agents. Firstly, the C1 and C4 postitioning of the hydroxyethylamino side chains on MIT, CI941 and AMET is associated with a lack of flavin reductase-mediated activation of these agents. Secondly, the possession of a C5 or C8 aromatic hydroxyl group appears to be intimately involved in the enhanced DNA strand breakage and cytotoxic potency of MIT and CI941, since AMET does not possess these groups. These findings indicate that future development of quinone antitumour agents should concentrate on compounds that do not undergo redox cycling but do possess aromatic hydroxyl groups, since the latter appear to be responsible for the enhanced cytotoxicity of MIT and CI941.Abbreviations DOX
doxorubicin
- MIT
mitoxantrone
- AMET
ametantrone
- SOD
superoxide dismutase
- DMPO
5,5-dimethyl-1-pyrroline-N-oxide
- ESR
electron spin resonance
- SSF
strand scission factor
This work was funded by the Cancer Research Campaign (UK) 相似文献
56.
Clinical and laboratory findings are described in the case of a patient with a vein of Galen aneurysm who presented with recurrent aseptic meningitis for which no etiology could be identified. The patient subsequently developed thalamic and intraventricular hemorrhage associated with partial thrombosis of the dilated vein of Galen. Review of the literature revealed no previously reported association of these conditions. Recurrent cerebral venous thrombosis involving the fistula is hypothesized as the cause of repeated inflammatory reactions near the subarachnoid space. More extensive thrombosis may then have precipitated the hemorrhage. 相似文献
57.
58.
A J Buckton R Kulasegaram S L Ngui M Fisher R James S Rangarajan C G Teo 《Journal of clinical virology》2007,40(1):60-63
An HIV-1/hepatitis C virus (HCV) co-infected patient with haemophilia received a 48-week course of pegylated interferon-alpha-2b and ribavirin therapy for genotype 5a HCV infection. Virological response was achieved at week 24. At the end of treatment, HCV RNA in serum was detected and identified to belong to genotype 2b, rather than genotype 5a. A sensitive method for identifying minority HCV genotypes in pre-treatment serum showed genotype 2b HCV carriage prior to treatment. Sequencing the interferon sensitivity-determining region of the HCV NS5A gene obtained from pre-, intra- and post-treatment sera revealed emergence of quasispecies bearing R-->K and M-->A/T mutations at codons 2222 and 2223, respectively. Occult presence of minority HCV subpopulations and their acquisition of mutations following therapy can result in poor treatment outcome. 相似文献
59.
E J Beck K Tolley A Power S Mandalia P Rutter J Izumi J Beecham A Gray D Barlow P Easterbrook M Fisher J Innes G Kinghorn B Mandel A Pozniak A Tang D Tomlinson I Williams 《PharmacoEconomics》1998,14(6):639-652
OBJECTIVE: The aim of the study was to measure the use and estimate the cost of HIV service provision in England. DESIGN AND SETTING: Standardised activity and case-severity data were collected prospectively in 10 English HIV clinics (5 London and 5 non-London sites) for the periods 1 January 1996 to 30 June 1996 and 1 July 1996 to 31 December 1996 and linked to unit cost data. In total, 5440 patients with HIV infection attended during the first 6 months and 5708 during the second 6 months in 1996. MAIN OUTCOME MEASURES AND RESULTS: The mean number of inpatient days per patient-year for patients with AIDS was 19.7 [95% confidence interval (CI): 13.7 to 25.7] for January to June and 20.8 (95% CI: 15.3 to 26.4) for July to December 1996. The mean number of outpatient visits for asymptomatic patients with HIV infection was 14.8 (95% CI: 11.9 to 17.6) and 13.3 (95% CI: 10.8 to 15.7) for the respective periods and 16.1 (95% CI: 13.21 to 18.97) and 15.7 (95% CI: 11.2 to 20.2), respectively, for patients with symptomatic non-AIDS (i.e. symptomatic patients with HIV infection but without AIDS-defining conditions). Substantial centre-to-centre variation was observed, suggesting that many clinics can continue the shift from an inpatient- to an outpatient-based service. Cost estimates per patient-year for HIV service provision for 1996 varied from 4695 Pounds (95% CI: 3769 Pounds to 5648 Pounds) for asymptomatic patients, to 7605 Pounds (95% CI: 6273 Pounds to 8909 Pounds) for symptomatic non-AIDS patients to 20,358 Pounds (95% CI: 17,681 Pounds to 23,206 Pounds) for patients with AIDS. CONCLUSIONS: Different combinations of antiretroviral therapy affect the cost estimates of HIV service provision differently. Anticipated reduction in inpatient-related activity through the increased use of combination antiretroviral therapy will further shift service provision from an inpatient- to outpatient-based service and reduce costs per patient-year. The extent and duration of such effects are currently unknown. The long term effects of combination treatment on the morbidity and mortality patterns of individuals infected with HIV are also currently unknown, as are their implications on the use and cost of HIV service provision. Multicentre databases like the National Prospective Monitoring System (NPMS) will provide healthcare professionals with information to improve existing services and anticipate the impact of new developments. 相似文献
60.
M Greenleaf S Fisher C Miaskowski K DuHamel 《The American journal of clinical hypnosis》1992,35(2):119-128
We studied 32 coronary bypass patients to examine the effect of hypnosis on recovery from surgery. The patients were assessed for hypnotizability with the Hypnotic Induction Profile (HIP) and assigned to experimental groups with a random stratification procedure to equate for differences in hypnotizability, age, and severity of illness. We taught patients in groups one and two formal hypnosis with different treatment strategies; patients in group three were not taught formal hypnosis or a treatment strategy. Scores on the HIP were significant predictors of recovery, independent of experimental treatment with formal hypnosis. Patients who scored "Midrange" stabilized more quickly in the intensive care unit (ICU) than those who scored "High" or "Low" (p = < .05). Patients who scored "High" had more labile blood pressure in the ICU compared to the "Midrange" and "Lows" (p = < .05). Measured hypnotizability was associated with the recovery sequence from surgery. 相似文献