全文获取类型
收费全文 | 3864篇 |
免费 | 297篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 89篇 |
妇产科学 | 67篇 |
基础医学 | 419篇 |
口腔科学 | 82篇 |
临床医学 | 419篇 |
内科学 | 1192篇 |
皮肤病学 | 58篇 |
神经病学 | 396篇 |
特种医学 | 164篇 |
外科学 | 433篇 |
综合类 | 168篇 |
预防医学 | 200篇 |
眼科学 | 67篇 |
药学 | 229篇 |
中国医学 | 4篇 |
肿瘤学 | 163篇 |
出版年
2022年 | 27篇 |
2021年 | 36篇 |
2020年 | 38篇 |
2019年 | 45篇 |
2018年 | 52篇 |
2017年 | 50篇 |
2016年 | 45篇 |
2015年 | 63篇 |
2014年 | 92篇 |
2013年 | 144篇 |
2012年 | 151篇 |
2011年 | 171篇 |
2010年 | 118篇 |
2009年 | 117篇 |
2008年 | 150篇 |
2007年 | 186篇 |
2006年 | 140篇 |
2005年 | 163篇 |
2004年 | 137篇 |
2003年 | 125篇 |
2002年 | 129篇 |
2001年 | 114篇 |
2000年 | 123篇 |
1999年 | 112篇 |
1998年 | 72篇 |
1997年 | 68篇 |
1996年 | 55篇 |
1995年 | 52篇 |
1994年 | 52篇 |
1993年 | 55篇 |
1992年 | 61篇 |
1991年 | 54篇 |
1990年 | 61篇 |
1989年 | 98篇 |
1988年 | 80篇 |
1987年 | 80篇 |
1986年 | 74篇 |
1985年 | 61篇 |
1984年 | 46篇 |
1983年 | 51篇 |
1982年 | 30篇 |
1981年 | 36篇 |
1980年 | 34篇 |
1979年 | 38篇 |
1978年 | 41篇 |
1977年 | 35篇 |
1976年 | 27篇 |
1975年 | 23篇 |
1974年 | 24篇 |
1973年 | 26篇 |
排序方式: 共有4188条查询结果,搜索用时 0 毫秒
91.
Robert D. Cannon Gillian A. Beauchamp Paige Roth Jennifer Stephens David B. Burmeister David M. Richardson Alanna M. Balbi Tennessee D. Park Stephen W. Dusza Marna Rayl Greenberg 《Clinical therapeutics》2018,40(2):197-203
Purpose
Substance use and misuse is prevalent in emergency department (ED) populations. While the prevalence of substance use and misuse is reported, sex-specific trends in ED populations have not been documented. We set out to determine the sex-specific prevalence of ED patient substance use during this current epidemic.Methods
A retrospective electronic data abstraction tool, developed for quality-improvement purposes, was used to assess ED visits in 3 hospitals in northeastern Pennsylvania. All patients with ED diagnosis codes for substance use F10.000 through F 19.999 (excluding F17 codes for nicotine) were abstracted for network ED visits at all 3 hospitals. Data points included ED clinical enrollment site, primary substance used, sex, date of ED visit, disposition (including left without being seen, left against medical advice, discharged, admitted, and treatment in rehabilitation) for 18 months (January 1, 2016 through July 31, 2017). The categorical parameters of sex, clinical enrollment site, diagnosis, date of ED visit, and disposition status were summarized as a proportion of the subject group. Time series analysis was used to assess trends in substance use and misuse visits by patient sex.Findings
A total of 10,511 patients presented to the EDs during the study time period with a final diagnosis of a substance use?related reason and were included in the analysis. The mean age for these patients was 43.6 (SD 16.4) years, and the majority was male (65.6%, n = 6900). The most common substance in the final diagnosis for the ED visit was alcohol (54.3%; 95% CI, 53.3–55.2), followed by opioids (19.2%; 95% CI, 18.4–19.9) and cannabis (14.4%; 95% CI, 13.7–15.0). Females tended to be younger than males (42.4 years vs 44.3 years; P < 0.001), and were more likely to be discharged after the ED visit than males (36.1% vs 32.3%; P < 0.001). When exploring differences in age by sex and substance, males with a final diagnosis including alcohol- and cannabis-related issues were older than females, whereas females diagnosed with opioid-related reasons were older than males (41.3 vs 38.9 years; P < 0.001).Implications
There are sex-specific differences in prevalence of patients presenting with substance use in the ED setting. 相似文献92.
Preclinical Research |
93.
94.
Leflunomide 总被引:1,自引:0,他引:1
Leflunomide is a low-molecular weight, synthetic, oral agent specifically developed for immunosuppression. Because of activity in animal models, leflunomide was tested in rheumatoid arthritis(RA). These investigations have demonstrated that leflunomide reduces the clinical symptoms and signs of RA, improves health related quality of life, and retards structural damage. Leflunomide has been evaluated in RA patients as monotherapy and in combination with methotrexate. Close monitoring for adverse events with particular attention for monitoring liver enzymes for hepatic toxicity is important during treatment with leflunomide. 相似文献
95.
G Eisenhofer M D Esler I T Meredith A Dart R O Cannon A A Quyyumi G Lambert J Chin G L Jennings D S Goldstein 《Circulation》1992,85(5):1775-1785
BACKGROUND. Measurement of cardiac norepinephrine spillover may indicate the amount of transmitter at neuroeffector sites but does not distinguish neuronal release or reuptake in determining this amount or provide information about other aspects of sympathetic function. This report examines how cardiac spillover of the norepinephrine metabolite dihydroxyphenylglycol (DHPG) provides additional distinct information about cardiac sympathetic function. METHODS AND RESULTS. Arterial and coronary venous blood samples were taken during cardiac catheterization and intravenous infusion of [3H]norepinephrine in 57 subjects. Subjects were given intravenous yohimbine or underwent mental stress, handgrip exercise, and cycling exercise to activate sympathetic nerves or were given intravenous desipramine to block norepinephrine reuptake. Cardiac DHPG spillover (601 +/- 41 pmol/min) was eightfold greater than norepinephrine spillover (78 +/- 10 pmol/min) at rest and increased during sympathetic activation by 65% of the increase of norepinephrine. This and the desipramine-sensitive cardiac production of [3H]-labeled DHPG from [3H]norepinephrine indicated that 10.5 times more endogenous norepinephrine is recaptured than escapes into plasma; that more than 90% of recaptured norepinephrine is sequestered into storage vesicles; and that under resting conditions, most cardiac spillover of DHPG and turnover of norepinephrine are from metabolism of transmitter leaking from vesicles; the latter process is independent of exocytotic transmitter release with a rate at rest over 100-fold that of norepinephrine spillover and over 10-fold that of norepinephrine reuptake. CONCLUSIONS. Cardiac spillover of DHPG provides information about processes close to or within sympathetic nerve endings that cannot be provided by measurements of norepinephrine spillover alone. This includes quantitative information about the role of neuronal uptake in terminating the actions of norepinephrine at neuroeffector sites and the importance of vesicular-axoplasmic exchange of norepinephrine as a dynamic process contributing to norepinephrine turnover. 相似文献
96.
M G Pappas L T Cannon W T Hockmeyer D H Smith 《Annals of tropical medicine and parasitology》1985,79(2):147-151
Three complement fixation (CF) procedures were evaluated for their ability to detect serum antibodies to visceral leishmaniasis. These tests differ in their use of buffers, volumes of complement and sensitized erythrocyte concentrations, incubation times and percentage haemolysis endpoints. Freeze-thawed sonicates of Leishmania donovani promastignotes were used as antigen. Test sensitivity was determined using sera from 46 Kenyans with parasitologically proven leishmaniasis. The frequencies of positive reactions in all three tests were 96-97% and positive antibody titres ranged from 1:16 to 1:4096. Specificity was determined with 20 sera from healthy individuals with no known exposure to leishmaniasis. The frequencies of false positive reactions were 0-10% in the control sera, with titres up to 1:16. No cross-reactions were observed with sera from patients with bacterial, fungal and other parasitic diseases. In replicate experiments, 99-100% of the sera tested were within one titre dilution of each other. All three CF procedures provide very good sensitivity, specificity and low cross-reactivity and are statistically similar in their capacity to diagnose visceral leishmaniasis. 相似文献
97.
Purpose of Review
There has been confusion following the 2013 American College of Cardiology/American Heart Association (ACC/AHA) Lipid guidelines on the role of non-statin medications for cardiovascular prevention.Recent Findings
Several recent large trials have also now shown that lowering LDL with non-statins reduces cardiovascular events. In ASCVD patients on statins, adding ezetimibe or a PCSK9 inhibitor led to reductions in CV events in the IMPROVE IT, FOURIER, and most recently the ODYSSEY-OUTCOMES trials. Additional novel therapies reducing LDL and other atherogenic lipoproteins are in development during this exciting time in this field.Summary
With recent evidence, the 2017 ACC Expert Consensus Decision pathway calls for initial therapy with statins, monitoring LDL levels, and then adding ezetimibe and/or PCSK9 inhibitors to further lower LDL-C to targets based on the patient’s risk.98.
Halitosis, an offensive breath odour, has multiple sources and negative impacts on people’s social interactions and quality of life. It is important for health care professionals, including general physicians and dental professionals, to understand its aetiology and risk factors in order to diagnose and treat patients appropriately. In this study, we have reviewed the current literature on halitosis regarding its prevalence, classification, risk factors, sources, measurement and treatment. 相似文献
99.
100.
Robert F Storey Steen Husted Robert A Harrington Stanley Heptinstall Robert G Wilcox Gary Peters Mark Wickens H?kan Emanuelsson Paul Gurbel Peer Grande Christopher P Cannon 《Journal of the American College of Cardiology》2007,50(19):1852-1856
OBJECTIVES: In a substudy of DISPERSE (Dose confIrmation Study assessing anti-Platelet Effects of AZD6140 vs. clopidogRel in non-ST-segment Elevation myocardial infarction)-2, we compared the antiplatelet effects of AZD6140 and clopidogrel and assessed the effects of AZD6140 in clopidogrel-pretreated patients. BACKGROUND: Clopidogrel, in combination with aspirin, reduces cardiovascular events in patients with acute coronary syndromes (ACS). However, patients with poor inhibition of platelet aggregation with clopidogrel may be less well protected. AZD6140 is a reversible oral P2Y(12) receptor antagonist that has been studied in ACS patients in comparison with clopidogrel (DISPERSE-2 study). METHODS: Patients were randomized to receive either AZD6140 90 mg twice a day, AZD6140 180 mg twice a day, or clopidogrel 75 mg once a day for up to 12 weeks in a double-blind, double-dummy design. One-half the patients allocated AZD6140 received a 270-mg loading dose. Patients randomized to receive clopidogrel were given a 300-mg loading dose unless they had already been treated with clopidogrel. Adenosine diphosphate-induced platelet aggregation was assessed by optical aggregometry on day 1 and at 4-week intervals. RESULTS: AZD6140 inhibited platelet aggregation in a dose-dependent fashion and both doses achieved greater levels of inhibition than clopidogrel (e.g., 4 weeks, 4-h postdose [mean (+/-SD)]: clopidogrel 64% [+/-22%], AZD6140 90 mg 79% [+/-22%], AZD6140 180 mg 95% [+/-8%]. AZD6140 also produced further suppression of platelet aggregation in patients previously treated with clopidogrel. CONCLUSIONS: AZD6140 exhibited greater mean inhibition of platelet aggregation than a standard regimen of clopidogrel in ACS patients. In addition, AZD6140 further suppressed platelet aggregation in clopidogrel pretreated patients. 相似文献