全文获取类型
收费全文 | 5796篇 |
免费 | 497篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 252篇 |
妇产科学 | 87篇 |
基础医学 | 857篇 |
口腔科学 | 214篇 |
临床医学 | 694篇 |
内科学 | 914篇 |
皮肤病学 | 106篇 |
神经病学 | 467篇 |
特种医学 | 277篇 |
外科学 | 523篇 |
综合类 | 161篇 |
一般理论 | 6篇 |
预防医学 | 481篇 |
眼科学 | 364篇 |
药学 | 354篇 |
肿瘤学 | 515篇 |
出版年
2021年 | 69篇 |
2020年 | 42篇 |
2019年 | 84篇 |
2018年 | 94篇 |
2017年 | 71篇 |
2016年 | 62篇 |
2015年 | 102篇 |
2014年 | 117篇 |
2013年 | 204篇 |
2012年 | 250篇 |
2011年 | 243篇 |
2010年 | 165篇 |
2009年 | 143篇 |
2008年 | 230篇 |
2007年 | 231篇 |
2006年 | 244篇 |
2005年 | 202篇 |
2004年 | 239篇 |
2003年 | 186篇 |
2002年 | 189篇 |
2001年 | 203篇 |
2000年 | 166篇 |
1999年 | 167篇 |
1998年 | 89篇 |
1997年 | 91篇 |
1996年 | 74篇 |
1995年 | 72篇 |
1994年 | 66篇 |
1993年 | 69篇 |
1992年 | 122篇 |
1991年 | 125篇 |
1990年 | 116篇 |
1989年 | 130篇 |
1988年 | 117篇 |
1987年 | 119篇 |
1986年 | 86篇 |
1985年 | 107篇 |
1984年 | 75篇 |
1983年 | 72篇 |
1982年 | 47篇 |
1980年 | 53篇 |
1979年 | 93篇 |
1978年 | 72篇 |
1977年 | 47篇 |
1976年 | 61篇 |
1975年 | 70篇 |
1974年 | 57篇 |
1973年 | 53篇 |
1972年 | 63篇 |
1971年 | 44篇 |
排序方式: 共有6316条查询结果,搜索用时 15 毫秒
41.
42.
Holland WG 《Health facilities management》1990,3(10):49-50, 52
43.
A recently concluded demonstration project examined efforts to improve the effectiveness of nonprofit boards. This article focuses on the interventions at two participating healthcare organizations and examines the outcomes of these efforts. Changes made at the Alpha Health Care system included: reduction in the number of boards, term limits established for board members, election of new board chairs for two of the fewer boards, reduction in the size of those boards, implementation of a consent agenda, and reorganization of the boards' committee structure. Fewer changes were implemented at the Beta Hospital, where several initiatives were started but only some of which were retained by the projects' conclusion. Key factors limiting the extent of changes there were the modest interest in an active board by a new CEO and the limited investment of trustees in change. The article concludes with a discussion of lessons learned about board assessment, the use of retreats to initiate board development, and the importance of time management and CEO support to strengthen board effectiveness. 相似文献
44.
45.
A method is described for investigating life course influences on health in early old age. The lives of some 300 individuals at present aged 65-75 y have been reconstructed from the archived records of a pre-WWII survey, in which they took part as children, and from lifegrid interviews with the same individuals 60 y later. Despite loss to study at several points those interviewed are shown to be representative of the British population socio-demographically, in comparison with the 1931 and 1991 decennial censuses, and physically, in comparison with the Health Survey for England. Bias is conservative because the most disadvantaged were disproportionately affected by loss to follow-up through death and because non-responders to interview were more disadvantaged as children than the interviewees. Representativeness and conservative bias, it is argued, justify the use of these data for investigating life course influences on health in early old age. 相似文献
46.
Hamad AM Range SP Holland E Knox AJ 《American journal of respiratory cell and molecular biology》1999,20(5):1087-1095
We previously showed that cultured human airway smooth-muscle cells (HASMC) contain soluble and particulate guanylyl cyclases (GCs). We studied the desensitization of soluble and particulate GCs in HASMC. Homologous desensitization of soluble GC occurred after incubation with S-nitroso-N-acetyl pencillamine (SNAP). SNAP-dependent desensitization was blocked by hemoglobin, a nitric oxide (NO) scavenger, suggesting that it was due to NO release. Cross-desensitization between SNAP and sodium nitroprusside (SNP) and the lack of thiol reduction after SNAP or SNP treatment suggested that thiol depletion was not involved. Assays for soluble GC activity and experiments using protein synthesis inhibitors suggested that SNAP-dependent desensitization was due to reduced soluble GC. Homologous desensitization of particulate GC occurred after pretreatment with atrial natriuretic peptide (ANP) accompanied by reduced particulate GC activity. Recovery required protein synthesis, suggesting that it was due to reduction in particulate GC. Homologous desensitization to either SNAP or ANP was not altered by phosphodiesterase (PDE) inhibitors, suggesting that increased PDE activity was not involved. Cross-desensitization experiments using SNAP and ANP and experiments using zaprinast to elevate cyclic guanosine monophosphate showed no evidence of heterologous desensitization. Our results suggest that pretreatment of HASMC with SNAP or ANP causes homologous, but not heterologous, desensitization of soluble and particulate GCs, respectively. 相似文献
47.
In April 1998 an outbreak of salmonellosis amongst guests at a wedding feast was investigated. Of the 58 attendees interviewed 38 (66%) subsequently developed gastrointestinal symptoms. Stool cultures from 7 cases grew Salmonella Typhimurium RDNC A045. Food samples were culture-negative for Salmonella spp. A cohort study implicated spatchcock (RR 2.5, 95% CI 1.09-5.77) and scampi (RR 2.0, 95% CI 1.05-3.89). Temperature abuse and cross-contamination within the kitchen during preparation and cooking are likely to have been the main contributing factors to this outbreak. Control measures included staff education in safe food handling and improvements in poultry processing methods to minimise carcass contamination. 相似文献
48.
49.
Holland GN 《American journal of ophthalmology》1999,128(4):502-505
PURPOSE: To review recent observations regarding the sources of Toxoplasma gondii infection and rates of ocular involvement in cases of infection acquired after birth, and to reconcile them with older observations and widely held beliefs about the pathogenesis of ocular toxoplasmosis. METHOD: A review of pertinent reports from the medical literature. RESULTS: There are several potential sources and routes of infection, including inhalation of spores and ingestion of contaminated drinking water, that were previously unrecognized. Ocular involvement in cases of acquired infection appears to be more common than heretofore believed. A variety of host and parasitic factors may influence rates of ocular infection and the characteristics of ocular disease. CONCLUSIONS: The scars from which recurrent toxoplasmic retinochoroiditis arise may be the result of remote, acquired infections in many cases, rather than the residua of congenital infections, as commonly assumed. A better understanding of the epidemiology of T. gondii infection, as well as the host and parasitic factors that influence disease presentation, is important for developing strategies for prevention and management of ocular toxoplasmosis. 相似文献
50.
Effect of montelukast on the pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers
Van Hecken A Depré M Verbesselt R Wynants K De Lepeleire I Arnout J Wong PH Freeman A Holland S Gertz B De Schepper PJ 《Journal of clinical pharmacology》1999,39(5):495-500
Montelukast, a cysteinyl leukotriene receptor antagonist, is being developed for the treatment of asthma and related diseases. This study was designed to evaluate whether montelukast at clinically used dosage levels would interfere with the anticoagulant effect of warfarin. In a two-period, double-blind, randomized crossover study, 12 healthy male subjects received a single oral dose of 30 mg warfarin on the 7th day of a 12-day treatment with montelukast, 10 mg daily by mouth, or a placebo. Montelukast had no significant effect on the area under the plasma concentration-time curves and peak plasma concentrations of either R- or S-warfarin. However, slight but statistically significant decreases in time to peak concentration of both warfarin enantiomers and in elimination half-life of the less potent R-warfarin were observed in the presence of montelukast. These changes were not considered as clinically relevant. Montelukast had no significant effect on the anticoagulant effect of warfarin, as assessed by the international normalized ratio (INR) for prothrombin time (AUC0-144 and INR maximum). The results of this study suggest that a clinically important interaction between these drugs is unlikely to occur in patients requiring concomitant administration of both drugs. 相似文献