全文获取类型
收费全文 | 82072篇 |
免费 | 5978篇 |
国内免费 | 2038篇 |
专业分类
耳鼻咽喉 | 437篇 |
儿科学 | 1264篇 |
妇产科学 | 1337篇 |
基础医学 | 7907篇 |
口腔科学 | 1222篇 |
临床医学 | 8605篇 |
内科学 | 14033篇 |
皮肤病学 | 819篇 |
神经病学 | 2478篇 |
特种医学 | 1526篇 |
外国民族医学 | 14篇 |
外科学 | 3699篇 |
综合类 | 10933篇 |
现状与发展 | 15篇 |
预防医学 | 9582篇 |
眼科学 | 528篇 |
药学 | 16768篇 |
36篇 | |
中国医学 | 2331篇 |
肿瘤学 | 6554篇 |
出版年
2024年 | 185篇 |
2023年 | 1137篇 |
2022年 | 2481篇 |
2021年 | 3450篇 |
2020年 | 2780篇 |
2019年 | 2584篇 |
2018年 | 2589篇 |
2017年 | 2534篇 |
2016年 | 2877篇 |
2015年 | 3221篇 |
2014年 | 5800篇 |
2013年 | 6795篇 |
2012年 | 5505篇 |
2011年 | 6069篇 |
2010年 | 4562篇 |
2009年 | 4382篇 |
2008年 | 4492篇 |
2007年 | 4196篇 |
2006年 | 3561篇 |
2005年 | 3093篇 |
2004年 | 2545篇 |
2003年 | 2048篇 |
2002年 | 1649篇 |
2001年 | 1483篇 |
2000年 | 1201篇 |
1999年 | 1083篇 |
1998年 | 842篇 |
1997年 | 790篇 |
1996年 | 655篇 |
1995年 | 590篇 |
1994年 | 586篇 |
1993年 | 431篇 |
1992年 | 428篇 |
1991年 | 341篇 |
1990年 | 290篇 |
1989年 | 254篇 |
1988年 | 241篇 |
1987年 | 257篇 |
1986年 | 187篇 |
1985年 | 289篇 |
1984年 | 255篇 |
1983年 | 158篇 |
1982年 | 177篇 |
1981年 | 143篇 |
1980年 | 147篇 |
1979年 | 105篇 |
1978年 | 90篇 |
1977年 | 92篇 |
1976年 | 102篇 |
1975年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
The Problem of Intractability: The Continuing Need for New Medical Therapies in Epilepsy 总被引:7,自引:3,他引:4
Pierre Jallon 《Epilepsia》1997,38(S9):S37-S42
Summary: Treatment of epilepsy, one of the most common neurologic disorders, has evolved from "institutional" poly-therapy to "dogmatic" monotherapy, and, most recently, to "rational" polypharmacy. The introduction of bromides for the treatment of epilepsy was followed first by phenobarbital and then by phenytoin as therapeutic options. Although attempts to combine medications were legion, none was supported by studies that demonstrated the benefit of such combinations. The issue of adverse effects became a principal argument in favor of monotherapy. Monotherapy, using newly developed drugs, avoided problems due to drug interactions but was ineffective in 20–30% of patients. A greater understanding of basic disease mechanisms and developments in molecular biology have led to an increased number of effective drugs for the estimated 6–12% of patients with epilepsy whose condition is intractable. Clinical research continues to build on the work of basic scientists in attempting to develop treatments based on a desire to move beyond the palliative and to affect the causative mechanisms of the disease. Novel medical approaches now under exploration include the use of drugs with complementary mechanisms of action, stimulation of various components of the nervous system, biochemical manipulations, focal intracerebral drug perfusion, and gene therapy. 相似文献
132.
Pharmacological interactions between serotonin and dopamine on behavior in the squirrel monkey 总被引:2,自引:1,他引:1
The behavioral effects of GBR 12909, a selective dopamine uptake inhibitor, were determined in squirrel monkeys trained to
respond under a fixed-interval (FI) schedule of stimulus termination and a second-order schedule of IV drug self-administration.
Intermediate doses of GBR 12909 increased FI response rate markedly, and the highest dose decreased response rate below control
values. The 5HT uptake inhibitors, alaproclate and fluoxetine, and the 5HT agonist, quipazine, attenuated the behavioral-stimulant
effects of GBR 12909, whereas the 5HT2A/2C antagonist, ritanserin, enhanced the behavioral-stimulant effects of the lowest dose. GBR 12909 reliably maintained self-administration,
and ritanserin increased response rate maintained by the highest dose. The dopamine agonist, quinpirole, increased FI response
rate in only one of three subjects, and ritanserin enhanced the behavioral-stimulant effects of quinpirole in that subject.
The dopamine agonist, apomorphine, only decreased FI response rate, and ritanserin did not alter its behavioral effects. The
pharmacological profile of GBR 12909 administered alone and in combination with selective 5HT drugs in the present study was
similar to that obtained previously with cocaine, further demonstrating that 5HT can reliably modulate the behavioral effects
of psychomotor stimulants with prominent dopaminergic actions.
Received: 9 July 1996 / Final version: 22 November 1996 相似文献
133.
Neuropharmacology and Drug Interactions in Clinical Practice 总被引:2,自引:2,他引:0
Nina M. Graves 《Epilepsia》1995,36(S2):S27-S33
Summary: Absorption, distribution, and clearance are key pharmacokinetic principles. These parameters can be highly variable among patients and among compounds, and are factors that must be considered in the wide variability in response to medications. Current antiepileptic drugs (AEDs) present many challenges in their administration. However, understanding and utilizing pharmacokinetic principles can assist the clinician in the appropriate optimization of AEds. 相似文献
134.
目的:解释血压在毛细血管前阻力血管中下降最快的原因。方法:利用物理模型简化复杂的心血管系统。结果:全身所有的微、小动脉段“并联”,全身所有的毛细血管段“并联”。结论:微、小动脉段的总流阻最大、使俐血压在微、小动脉中下降最快。 相似文献
135.
136.
Drug related hospital admissions 总被引:13,自引:0,他引:13
J. Hallas B. Harvald J. Worm J. Beck-Nielsen L. F. Gram E. Grodum N. Damsbo J. Schou H. Kromann-Andersen F. Frølund 《European journal of clinical pharmacology》1993,45(3):199-203
Summary As part of a high-intensity monitoring study of drug events as the cause of admission to departments of internal medicine, the effect of an educational intervention programme was studied. Two departments were included, one specialising in geriatrics and one that received patients by non-selected referral. The series consisted of 607 consecutive admissions studied before and 703 after the intervention. The drug events considered were adverse drug reactions and dose-related therapeutic failures, mainly due to non-compliance.A modest, statistically non-significant decrease in drug related hospital admissions (DRH) was seen, from 14% before to 13% after the intervention period. However, DRHs classified as definitely avoidable showed the significant decrease of 83%.There was no apparent relationship between the topics selected for the intervention programme and changes in the pattern of DRHs. No relationship between alterations in sales data and hospital admissions caused by a given drug could be demonstrated. A blinded external evaluation of case abstracts did not disclose any significant shift in the investigators' assessments.The intervention may have had an non-specific effect on avoidable DRHs. 相似文献
137.
Southern blot hybridization and pneumococcal transformation were used to study the epidemiology at a molecular level of the genes for chloramphenicol resistance (cat) in streptococci and staphylococci. The cat gene of staphylococcal plasmid pC194 showed homology to the cat genes of the chromosomal elements of 5 different strains of Streptococcus pneumoniae and of Streptococcus agalactiae B109. DNA sequence homology was also detected between the cat gene of staphylococcal plasmid pC221 and the cat gene of broad host range conjugative plasmid pIP501, originally isolated from S. agalactiae. Two different cat genes appear to be present in clinical isolates of both streptococci and staphylococci. 相似文献
138.
Cocaethylene, a psychoactive metabolite resulting from combined ethanol/cocaine consumption, is of interest because its psychostimulant properties may partially underlie combined cocaine/ethanol use, and because it has the potential for use as a probe of drug reward mechanisms due to its enhanced selectivity at monoamine uptake sites compared to cocaine. To determine the relative systemic bioavailabilities of cocaine and cocaethylene, sequential plasma samples were obtained from awake rats following drug administration. Following intravenous administration of 3 µmol/kg (molar equivalent of 1 mg/kg cocaine-HCl), both drugs achieved similar time courses and areas under the plasma concentration versus time curve. In contrast, intraperitoneal administration of 44 µmol/kg (molar equivalent of 15 mg/kg cocaine HCl) showed peak plasma levels, and the area under the plasma concentration vs time curve for cocaine to be approximately twice that for cocaethylene. Comparison of dose corrected areas under the curve of the two routes of administration for each drug indicated that relative systemic bioavailability of cocaethylene following intraperitoneal administration is only 58% that of cocaine. In addition, the elimination of both cocaine and cocaethylene was found to be slower following intraperitoneal administration compared to the intravenous route. The implications of these results are discussed with respect to the relative potency of these two compounds, as inferred from behavioral, drug reward, and lethality studies. Also, the differences noted will need to be taken into account when making mechanistic interpretations from comparative drug reward studies. 相似文献
139.
A. Bryskier 《Clinical microbiology and infection》2002,8(2):65-69
The worldwide spread of erythromycin A-resistant streptococci, including Streptococcus pneumoniae , is of concern. Many studies have demonstrated that the viridans group streptococci can be a reservoir of erythromycin A resistance. Within oral streptoccoci, an important difference in the susceptibility pattern has been noted. The purpose of this short editorial is to highlight the importance of this group of bacteria as a reservoir of resistance to erythromycin A and the possible transfer of resistance to S. pneumoniae and S. pyogenes. 相似文献
140.
To investigate the relationship between age and renal vascular resistance and to establish nomative data of the systolic/diastolic
ratio (S/D ratio), pulsatility index (PI), and resistant index (RI) of the renal artery in the normal pediatric population,
we studied 252 normal children aged newborn to 13 years (a total of 449 kidneys) with a color Doppler unit. After the normality
of the kidney was established, color flow mapping was performed to localize the segmental portion of the renal artery. Flow
velocity waveforms were then obtained by pulsed Doppler, and S/D ratio, PI, and RI were calculated. Multiple regression analysis
confirmed the age dependence of the S/D ratio, PI, and RI of the renal artery in normal children. Renal vascular resistance
continuously declines after birth and stabilizes at the age of 102 – 130 months. Normative data for S/D ratio, PI, and RI
of the renal artery in normal children were established for each age group. Since renal vascular resistance decreases with
age and stabilizes at 8 – 10 years, we suggest using different normal ranges for each age group when studying renal vascular
resistance in pediatric patients.
Received October 5, 1995; received in revised form and accepted April 24, 1996 相似文献