全文获取类型
收费全文 | 1516035篇 |
免费 | 117830篇 |
国内免费 | 3601篇 |
专业分类
耳鼻咽喉 | 19918篇 |
儿科学 | 49660篇 |
妇产科学 | 43495篇 |
基础医学 | 214933篇 |
口腔科学 | 41421篇 |
临床医学 | 132589篇 |
内科学 | 310095篇 |
皮肤病学 | 36742篇 |
神经病学 | 125114篇 |
特种医学 | 56185篇 |
外国民族医学 | 464篇 |
外科学 | 223395篇 |
综合类 | 33330篇 |
现状与发展 | 3篇 |
一般理论 | 521篇 |
预防医学 | 120530篇 |
眼科学 | 33830篇 |
药学 | 105835篇 |
1篇 | |
中国医学 | 3853篇 |
肿瘤学 | 85552篇 |
出版年
2021年 | 13225篇 |
2019年 | 14259篇 |
2018年 | 20800篇 |
2017年 | 15125篇 |
2016年 | 16488篇 |
2015年 | 18503篇 |
2014年 | 25488篇 |
2013年 | 37837篇 |
2012年 | 53155篇 |
2011年 | 56188篇 |
2010年 | 32381篇 |
2009年 | 30047篇 |
2008年 | 50897篇 |
2007年 | 53855篇 |
2006年 | 53777篇 |
2005年 | 52168篇 |
2004年 | 49363篇 |
2003年 | 46932篇 |
2002年 | 45163篇 |
2001年 | 75499篇 |
2000年 | 77478篇 |
1999年 | 63769篇 |
1998年 | 17408篇 |
1997年 | 15690篇 |
1996年 | 15834篇 |
1995年 | 14991篇 |
1994年 | 13558篇 |
1993年 | 12723篇 |
1992年 | 46691篇 |
1991年 | 44203篇 |
1990年 | 42199篇 |
1989年 | 40117篇 |
1988年 | 36648篇 |
1987年 | 35822篇 |
1986年 | 33354篇 |
1985年 | 31684篇 |
1984年 | 24128篇 |
1983年 | 20261篇 |
1982年 | 12325篇 |
1981年 | 10886篇 |
1979年 | 20984篇 |
1978年 | 14754篇 |
1977年 | 12255篇 |
1976年 | 11533篇 |
1975年 | 11848篇 |
1974年 | 14253篇 |
1973年 | 13836篇 |
1972年 | 12884篇 |
1971年 | 11747篇 |
1970年 | 11171篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
971.
972.
973.
We developed a homogeneous fluoroimmunoassay for detecting amphetamines in urine. Only fluorescence intensity need be measured because the emission of non-protein-bound fluorescein-labeled amphetamine is preferentially quenched by detergent micelles. In a previous reported prototype assay system for measuring gentamicin in serum we used fluorescein and dodecyl sulfate (Anal Chem 1985; 57:1928-30). We have found that favorable hydrophobic and (or) ionic character of the analyte and unfavorable polar and (or) ionic character of the fluor are important determinants of the desired interactions. An anionic detergent and fluorescein, therefore, should be appropriate for apolar of cationic analytes, such as gentamicin and amphetamines. A greater [H+] at the anionic micelle surface is important for quenching emission from the fluor moiety. Millimolar concentrations of dodecyl sulfate rapidly denature immunoglobulin unless hapten is bound with sufficiently high affinity. Affinity was sufficiently high for the antibody used in the prototype gentamicin assay but not for the amphetamine antibody. Thus for the amphetamine assay, we used a non-denaturing detergent, dodecyl(oxyethylene)12 sulfate. The assay requires 30 microL of specimen in 2 mL of total assay volume. Amphetamine(d-,dl-, and meth-), at a concentration of 1 mg per liter of urine, is readily detected. 相似文献
974.
W W Eaton A Romanoski J C Anthony G Nestadt 《The Journal of nervous and mental disease》1991,179(11):689-693
This analysis applies methods of screening to the problem of psychosis. A probability sample of 810 individuals from the Eastern Baltimore Mental Health Survey was interviewed in the self-report modality with the Diagnostic Interview Schedule and shortly thereafter by a psychiatrist. It is shown that a configuration of responses in the self-report modality can screen moderately well for psychosis, as measured by psychiatrists in the clinical modality. 相似文献
975.
976.
A technique for arthrodesis of small joints of the hand is described that uses a tenon to secure apposition that has good intrinsic stability as well as a large surface area of cancellous bony contact. A minimum of postoperative immobilization is required. The tenon arthrodesis method has been employed in 85 joints. The literature shows pseudoarthrosis rates of 0 to 33%. This technique had a 2.3% failure rate that compares favorably with those in other published series. 相似文献
977.
Postural changes of body equilibrium on a moving force plate were examined for sinusoidal movements, saccades and frequency whilst different stimuli were applied under various visual conditions. If a dynamic stimulus was used, the stabilization of vision shows a distinct visual-vestibular conflict which provokes postural disequilibrium. This is the cause of motion sickness during car driving. This disequilibrium is also the cause of the motor insecurity experienced during walking and reading at the same time. 相似文献
978.
Fetal beta-endorphin release has been associated with fetal hypoxia. The purpose of this study was to assess the degree of uterine blood flow reduction needed to elicit fetal beta-endorphin release in the sheep since there is a large reserve of oxygen supply to the fetus. Uterine blood flow was reduced by 26 +/- 2, 46 +/- 3 and 66 +/- 2%, producing fetal oxygen content concentrations of 5.7 +/- 0.6, 4.4 +/- 0.7 and 2.6 +/- 0.3 ml/dl, respectively. Although fetal oxygen concentrations were significantly decreased in the groups with a reduction in uterine blood flow of 46 and 66%, beta-endorphin was elevated only in the latter group. It is speculated that fetal beta-endorphin is released at a level of hypoxia which leads to a decrease in fetal oxygen consumption. A reduction in uterine blood flow of 66% appears to produce a stressful environment for the fetus as measured by fetal plasma beta-endorphin levels. 相似文献
979.
Otavio A C Clark Gary H Lyman Aldemar A Castro Luciana G O Clark Benjamin Djulbegovic 《Journal of clinical oncology》2005,23(18):4198-4214
PURPOSE: Current treatment for febrile neutropenia (FN) includes hospitalization for evaluation, empiric broad-spectrum antibiotics, and other supportive care. Clinical trials have reported conflicting results when studying whether the colony-stimulating factors (CSFs) improve outcomes in patients with FN. This Cochrane Collaboration review was undertaken to further evaluate the safety and efficacy of the CSFs in patients with FN. METHODS: An exhaustive literature search was undertaken including major electronic databases (CANCERLIT, EMBASE, LILACS, MEDLINE, SCI, and the Cochrane Controlled Trials Register). All randomized controlled trials that compare CSFs plus antibiotics versus antibiotics alone for the treatment of established FN in adults and children were sought. A meta-analysis of the selected studies was performed. RESULTS: More than 8,000 references were screened, with 13 studies meeting eligibility criteria for inclusion. The overall mortality was not influenced significantly by the use of CSF (odds ratio [OR] = 0.68; 95% CI, 0.43 to 1.08; P = .1). A marginally significant result was obtained for the use of CSF in reducing infection-related mortality (OR = 0.51; 95% CI, 0.26 to 1.00; P = .05). Patients treated with CSFs had a shorter length of hospitalization (hazard ratio [HR] = 0.63; 95% CI, 0.49 to 0.82; P = .0006) and a shorter time to neutrophil recovery (HR = 0.32; 95% CI, 0.23 to 0.46; P < .00001). CONCLUSION: The use of the CSFs in patients with established FN caused by cancer chemotherapy reduces the amount of time spent in hospital and the neutrophil recovery period. The possible influence of the CSFs on infection-related mortality requires further investigation. 相似文献
980.