全文获取类型
收费全文 | 8768篇 |
免费 | 824篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 338篇 |
妇产科学 | 196篇 |
基础医学 | 1201篇 |
口腔科学 | 408篇 |
临床医学 | 1101篇 |
内科学 | 1755篇 |
皮肤病学 | 191篇 |
神经病学 | 524篇 |
特种医学 | 598篇 |
外科学 | 1089篇 |
综合类 | 166篇 |
一般理论 | 5篇 |
预防医学 | 767篇 |
眼科学 | 92篇 |
药学 | 682篇 |
2篇 | |
中国医学 | 6篇 |
肿瘤学 | 509篇 |
出版年
2022年 | 60篇 |
2021年 | 107篇 |
2020年 | 89篇 |
2019年 | 106篇 |
2018年 | 146篇 |
2017年 | 98篇 |
2016年 | 113篇 |
2015年 | 134篇 |
2014年 | 197篇 |
2013年 | 271篇 |
2012年 | 295篇 |
2011年 | 339篇 |
2010年 | 261篇 |
2009年 | 221篇 |
2008年 | 299篇 |
2007年 | 370篇 |
2006年 | 349篇 |
2005年 | 348篇 |
2004年 | 273篇 |
2003年 | 254篇 |
2002年 | 278篇 |
2001年 | 262篇 |
2000年 | 259篇 |
1999年 | 282篇 |
1998年 | 217篇 |
1997年 | 240篇 |
1996年 | 203篇 |
1995年 | 166篇 |
1994年 | 159篇 |
1993年 | 160篇 |
1992年 | 220篇 |
1991年 | 204篇 |
1990年 | 186篇 |
1989年 | 175篇 |
1988年 | 193篇 |
1987年 | 163篇 |
1986年 | 177篇 |
1985年 | 187篇 |
1984年 | 129篇 |
1983年 | 98篇 |
1982年 | 90篇 |
1981年 | 101篇 |
1980年 | 68篇 |
1979年 | 77篇 |
1978年 | 65篇 |
1977年 | 73篇 |
1976年 | 68篇 |
1974年 | 78篇 |
1973年 | 74篇 |
1971年 | 62篇 |
排序方式: 共有9675条查询结果,搜索用时 15 毫秒
991.
992.
993.
Donald E. Tsai Monica Nearey Christine L. Hardy John E. Tomaszewski Robert M. Kotloff Robert A. Grossman Kim M. Olthoff Edward A. Stadtmauer David L. Porter Stephen J. Schuster Selina M. Luger Richard L. Hodinka 《American journal of transplantation》2002,2(10):946-954
Epstein-Barr virus (EBV) is known to be involved in the majority of patients who develop post-transplant lymphoproliferative disorder after solid organ transplant. We conducted a retrospective study to determine the utility of qualitative and quantitative Epstein-Barr virus polymerase chain reaction (PCR) for the diagnosis and monitoring of post-transplant lymphoproliferative disorder in adult solid organ transplant patients. Peripheral blood leukocytes obtained from 35 adult solid organ transplant patients consecutively referred for evaluation of possible post-transplant lymphoproliferative disorder, were tested by EBV PCR at the time of initial evaluation and at time points thereafter. Eighteen of 35 (51%) patients were ultimately diagnosed with post-transplant lymphoproliferative disorder by tissue biopsy. Fifteen of 18 (83%) patients were found to have EBER-1 positive tumors by in situ hybridization. EBV PCR was positive in 7 of 15 patients, suggesting a sensitivity of 39%. Seventeen patients without post-transplant lymphoproliferative disorder and three with EBER-1 negative post-transplant lymphoproliferative disorder all had negative EBV PCR tests, suggesting a specificity of 100%. We observed that declines in EBV DNA load were associated with response to therapeutic interventions, such as reduction in immunosuppression, rituximab therapy and chemotherapy. We conclude that peripheral blood EBV PCR may have a role in the diagnosis and monitoring of post-transplant lymphoproliferative disorder in adult solid organ transplant patients. 相似文献
994.
In naive mice, ibogaine at a tremorigenic dose (30 mg/kg, ip), did not produce antinociception but did potentiate the antinociceptive potency of morphine in the tail-flick test. In morphine-dependent mice, ibogaine did not eliminate withdrawal symptoms but significantly increased the number of repetitive vertical jumps induced by naloxone, whatever the duration of the chronic morphine treatment. By comparison, repetitive jumping induced by alpha-napthoxyacetic acid (alpha-NOAA), a non-convulsant drug which induced jumping without affecting other morphine-withdrawal signs, was not significantly modified by ibogaine. These results indicate that while acute antinociceptive effects of morphine are modulated by ibogaine, this drug, shown to alleviate opiate dependence in man, does not attenuate in mice opioid withdrawal manifestations. 相似文献
995.
Y Cottin JM Doise V Maupoil M Tannière-Zeller F Dalloz M Maynadié MK Walker P Louis PM Carli JE Wolf and L Rochette† 《Fundamental & clinical pharmacology》1998,12(2):236-241
Summary— Free radical species have been implicated as important agents involved in myocardial ischemic and reperfusion injuries. Superoxide is capable of mobilizing iron from ferritin and the released iron can cause hydroxyl formation from H2O2. The aim of this study was to evaluate the time-dependent increase in lipid peroxidation assessed by plasma thiobarbituric acid reactive substances (TBARS) and the relationship between lipid-peroxidation and the iron status. Peripheral venous blood samples were obtained from 17 men with acute myocardial infarction (AMI) before thrombolytic treatment (T0***) and 1, 2, 3, 4, 8, 12, 16, 20, 24 and 48 hours after commencing fibrinolytic treatment. The concentration of TBARS, the parameters of iron metabolism, serum myoglobin, creatine kinase, and creatine kinase-MB were measured. Early reperfusion was judged by regression of sinus tachycardia (ST) elevation and reduction of chest pain. Recanalization of coronary artery was evaluated by a late coronary angiography 24–96 hours after thrombolysis. After thrombolytic therapy, the TBARS level was raised from 2.98 ± 0.80 (T0***) to 4.57 ± 1.24 (peak), and decreased to 2.96 ± 0.40 nmol/mL plasma at T48 (T0 vs peak: P < 0.001, peak vs T48: P < 0.001, TO vs T48: NS). The mean time of the peak was observed at 9.7 ± 7.5 hours. The iron increased significantly from 0.67 ± 0.34 (T0) to 1.15 ± 0.52 mg/L (peak), and returned to the pre-reperfusion to levels: 0.53 ± 0.28 UI/L at T48 (T0 vs peak: P < 0.001, peak vs T48: P < 0.001, TO vs T48: NS). The mean time of the peak was observed at 9.4 ± 7.3 hours. In return, no correlation was found between the increase of plasma creatine-kinase activity, myoglobin and iron or between the biochemical markers and time of fibrinolytic therapy. The results confirmed the importance of the temporal relationship between lipid peroxidation and iron status after thrombolytic therapy. Our results are in agreement with the concept that antioxidant agents used in association with thrombolytic therapy might be useful. 相似文献
996.
R Baggaley P Godfrey-Faussett R Msiska D Chilangwa E Chitu J Porter M Kelly 《Occupational and environmental medicine》1995,52(9):565-569
OBJECTIVES--To evaluate the impact of HIV on businesses in Zambia and to assess attitudes towards HIV and HIV education in the workplace. METHODS--The personnel managers of 33 companies with a total workforce of 10,204 in Lusaka and in towns in the Copperbelt were visited by two members of the study team. The study was discussed and a questionnaire about the impact of HIV on their company was explained and left for completion from company records. RESULTS--All 33 questionnaires were returned. HIV was recognised to be a problem by 30 companies questioned. Seven said that it had affected recruitment and 11 production. 23 companies carried out pre-employment medicals. 17 companies demanded that some or all of their employees had an HIV test before employment. Nine companies were sure that a positive HIV test would prevent employment, 15 were unsure saying that there was no particular company policy. Two companies had recently changed their policy and had stopped discriminating against those with HIV. 12 companies had some HIV educational material available for their employees and five had someone (or an organisation that they used) to whom they could refer employees for HIV information and advice. Condoms were provided free to staff by five of the companies. All thought that HIV education in the workplace was an appropriate intervention. Mortality data showed a sevenfold increase in the crude mortality from 0.25-1.8 per 100 person-years from 1987-93, and an increasing trend in reported deaths from AIDS and HIV related conditions. CONCLUSIONS--HIV is having an important impact in the workplace in urban Zambia. Although many companies insist on pre-employment medicals, often including HIV testing, few have developed policies relating to test results. Some companies have instituted HIV education but there is a demand for this service to be available more widely. There has been a striking increase in mortalities in this working population, which seems likely to be related to HIV, although the cause of most deaths was not recorded. 相似文献
997.
998.
P Verwaerde MA Tran and JL Montastruc JM Senard with the technical collaboration of G Portolan 《Fundamental & clinical pharmacology》1997,11(6):567-575
Summary— Yohimbine has been proposed for the treatment of neurogenic orthostatic hypotension; however, no controlled trial has been performed in experimental models of orthostatic hypotension or in patients with autonomic failure. The aim of the present study was to compare the effects of yohimbine (0.05 mg/kg, intravenously [iv]) and placebo (saline) in a new model of neurogenic orthostatic hypotension obtained by sinoaortic denervation (SAD) in chloralose-anaesthetized dogs. Blood pressure, heart rate, noradrenaline plasma levels and systolic blood pressure and heart rate short-term variabilities (calculated on low frequency [40–50 MHz] and high frequency [390–490 MHz] bands) were measured in supine position and after a 10 min 80° head-up tilting. The drugs were administered in a double-blind cross-over randomized fashion. The head-up tilting performed in normal animals increased diastolic blood pressure (+12 ± 4 mmHg), heart rate (+39 ± 12 beats per minute [bpm]), the low frequency band of systolic blood pressure and noradrenaline plasma level, without changing systolic blood pressure or heart rate variability. In SAD dogs, a marked fall in systolic (-80 ± 11 mmHg) and diastolic (-43 ± 4 mmHg) blood pressures was observed within 1 min after placebo, without modification in heart rate, systolic blood pressure and heart rate short-term variabilities and noradrenaline plasma levels. In SAD dogs, yohimbine (0.05 mg/kg, iv) delayed the blood pressure fall elicited by head-up tilting, but failed to modify its magnitude. These results show that, in the model of orthostatic hypotension obtained by SAD, yohimbine, at an α2 -adrenoceptor selective dose (0.05 mg/kg), delays the fall in blood pressure elicited by head-up tilting. The effect of yohimbine can be explained by an increase in sympathetic tone. 相似文献
999.
1000.