全文获取类型
收费全文 | 15008篇 |
免费 | 1070篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 539篇 |
妇产科学 | 292篇 |
基础医学 | 1719篇 |
口腔科学 | 348篇 |
临床医学 | 1427篇 |
内科学 | 3377篇 |
皮肤病学 | 254篇 |
神经病学 | 1888篇 |
特种医学 | 385篇 |
外国民族医学 | 1篇 |
外科学 | 2149篇 |
综合类 | 154篇 |
一般理论 | 7篇 |
预防医学 | 1258篇 |
眼科学 | 212篇 |
药学 | 1035篇 |
中国医学 | 28篇 |
肿瘤学 | 950篇 |
出版年
2022年 | 99篇 |
2021年 | 180篇 |
2020年 | 148篇 |
2019年 | 223篇 |
2018年 | 236篇 |
2017年 | 215篇 |
2016年 | 242篇 |
2015年 | 252篇 |
2014年 | 348篇 |
2013年 | 487篇 |
2012年 | 753篇 |
2011年 | 799篇 |
2010年 | 437篇 |
2009年 | 397篇 |
2008年 | 743篇 |
2007年 | 753篇 |
2006年 | 788篇 |
2005年 | 682篇 |
2004年 | 569篇 |
2003年 | 605篇 |
2002年 | 539篇 |
2001年 | 455篇 |
2000年 | 503篇 |
1999年 | 405篇 |
1998年 | 167篇 |
1997年 | 172篇 |
1996年 | 154篇 |
1995年 | 161篇 |
1994年 | 114篇 |
1993年 | 116篇 |
1992年 | 298篇 |
1991年 | 308篇 |
1990年 | 283篇 |
1989年 | 264篇 |
1988年 | 227篇 |
1987年 | 207篇 |
1986年 | 214篇 |
1985年 | 217篇 |
1984年 | 172篇 |
1983年 | 138篇 |
1982年 | 101篇 |
1981年 | 111篇 |
1979年 | 153篇 |
1978年 | 123篇 |
1977年 | 110篇 |
1976年 | 100篇 |
1975年 | 123篇 |
1974年 | 116篇 |
1973年 | 105篇 |
1972年 | 95篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
David S. Park Paul Manowitz Stanley Stein Ronald D. Poretz 《Alcoholism, clinical and experimental research》1996,20(2):234-239
Several electrophoretic forms of human platelet arylsulfatase A (ASA), including variant type IIIa and normal type IVa , have been identified by nondenaturing polyacrylamide gel electrophoresis. An alcoholic population that we have analyzed is enriched in variant type IIIa compared with nonalcoholic psychiatric and normal controls. Individuals with the IIIa enzyme possess greatly reduced levels of ASA activity. To understand further the structural basis for the differences and their potential biological consequences, the nature of the ASA variant expressed by fibroblasts from different individuals was explored. The electrophoretic patterns of fibroblast ASA from the IIIa and IVa individuals differ in degree of phosphorylation. Furthermore, fibroblast ASA from IIIa individuals lacks an N -linked glycan found in ASA from IVa individuals. In addition, differences in peptide and/or posttranslational modification unrelated to the N -linked carbohydrate or phosphorylation exist between the fibroblast ASA from IIIa and IVa individuals. The finding that both fibroblasts and platelets exhibit related electrophoretic isoform patterns characteristic of the donor's ASA type allows for the use of fibroblasts to study the impact of ethanol on the metabolism of cells possessing different ASA types. 相似文献
12.
Poverty, health services, and health status in rural America 总被引:5,自引:0,他引:5
Access to health services for everyone has been a major policy goal in the United States: inequitable access is assumed to lead to inequitable health status, particularly for low-income groups. A sophisticated model of the relation between poverty, health care needs, service use, and health outcomes is used to analyze cross-sectional data on 7,823 adults from 36 rural communities. Improved access and use are helpful, but evidence clearly indicates that combined health and social initiatives will be necessary to reduce inequalities in health status. 相似文献
13.
S H Faro A R Turtz R A Koenigsberg F B Mohamed C Y Chen H Stein 《AJNR. American journal of neuroradiology》1997,18(8):1588
The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions. 相似文献
14.
Nicoletta Desideri Isabella Sestili Maria Luisa Stein Stefano Manarini Giuseppe Dell'Elba Chiara Cerletti 《Archiv der Pharmazie》1997,330(4):100-106
6-[(4-Quinolinyl)oxy]hexanoic acids and the corresponding esters were designed and synthesized as inhibitors of the production of arachidonic acid metabolites. The inhibitory activities were assayed in vitro by evaluation of serum leukotriene B4 and thromboxane B2 production. While all 6-[(4-quinolinyl)oxy]hexanoic acids and their esters proved to be inactive, the N-alkyl-4-quinolones, obtained as by-products in their synthesis, were found to be a new class of leukotriene biosynthesis inhibitors. 相似文献
15.
Three saxophone players with upper limb amputations have been successfully rehabilitated to play their musical instruments using skin-conductivity touch control. Each attained a standard of musicianship sufficient to perform the standard repertoire of the instrument in a concert setting. The mechanical and electrical modifications to the saxophone are described, as well as the principles of operation of the skin-conductivity touch control module. The touch control module is commercially available for prosthetists who wish to fit musicians or others with upper extremity amputations who require rapid accurate control of a number of channels of powered prosthetic function. 相似文献
16.
W L Young I Prohovnik E Ornstein N Ostapkovich M B Sisti R A Solomon B M Stein 《Neurosurgery》1990,27(2):257-66; discussion 266-7
To investigate the cerebral hemodynamic changes associated with obliteration of arteriovenous malformations (AVMs), we studied 26 patients undergoing total microsurgical AVM resection during isoflurane and N2/O2 anesthesia. Detectors were placed 5 to 6 cm from the margin of the lesion and in a homologous contralateral position. Cerebral blood flow (CBF) was measured using the intravenous xenon-133 technique before and after AVM resection, during both hypocapnia and normocapnia at each stage. Intraoperative changes in CBF were related to a risk score system based on the patient's history and preoperative angiograms. Seven otherwise healthy patients undergoing spinal surgery were studied to control for anesthetic effects. Patient demographic and clinical data for the AVM group conformed to the expected strata of a large AVM population. The CBF increased after excision (22 +/- 1 ml/100 g/min before excision to 30 +/- 2 ml/100 g/min after excision; mean +/- SE, n = 25, P less than 0.002) without a hemispheric difference. CO2 reactivity increased slightly after excision (4.2 +/- 0.3% change/mm Hg before excision to 4.7 +/- 0.3% change/mm Hg after excision; n = 14, P less than 0.02). The baseline CBF and CO2 reactivity were not different from the control group. There was a weak correlation between the risk score and the percentage of change in the ipsilateral CBF, with a trend for the patients with the lowest risk to have the lowest CBF changes after resection. There was no relationship between CO2 reactivity and risk grade. None of the patients awoke from anesthesia with unexpected neurological deficits. The highest CBF increases were associated with postoperative brain swelling in one patient and fatal intracerebral hemorrhage in another. Both patients had normal CO2 reactivity before excision. One patient suffered postoperative intracerebral hemorrhage, attributable to technical problems, and had no increase in CBF. We conclude that, with an acute increase in the arteriovenous pressure gradient (and cerebral perfusion pressure) that results from shunt obliteration, there is an immediate global effect of AVM resection to increase CBF. Cerebrovascular reactivity to CO2 remains intact both before and after excision. 相似文献
17.
18.
Anders Baerheim Per Hjortdahl Are Holen Tor Anvik Ole Bernt Fasmer Hilde Grimstad Tore Gude Terje Risberg Per Vaglum 《BMC medical education》2007,7(1):35
Background
Communication training builds on the assumption that understanding of the concepts related to professional communication facilitates the training. We know little about whether students' knowledge of clinical communication skills is affected by their attendance of communication training courses, or to what degree other elements of the clinical training or curriculum design also play a role. The aim of this study was to determine which elements of the curriculum influence acquisition of knowledge regarding clinical communication skills by medical students. 相似文献19.
20.
Brinerdin (Sandoz), a combination of a diuretic (clopamide 5 mg), a vasodilator (dihydro-ergocristine 0.5 mg) and reserpine (0.1 mg) (CDR) was compared with methyldopa (MD) plus hydrochlorothiazide (HCT) for antihypertensive effect, adverse reactions, compliance and patient preference in an open cross-over trial. Eighteen patients completed both arms of the trial and 5 patients who completed the CDR arm were withdrawn while on the MD arm because of adverse effects in 4 and poor control in 1. On HCT 50 mg daily the mean baseline systolic blood pressure was 163.9 +/- 16.3 mmHg and the diastolic blood pressure was 105.9 +/- 6.7 mmHg. On CDR these were reduced to systolic blood pressure 140.3 +/- 15.1 mmHg and diastolic blood pressure 87.8 +/- 9.3 mmHg. On MD + HCT the systolic blood pressure was reduced to 138.5 +/- 16.9 mmHg and the diastolic blood pressure to 88.9 +/- 10.3 mmHg. The differences between the two treatment periods in systolic blood pressure (1.8 mmHg; 95% confidence interval (CI) - 4.1 + 7.7 mmHg) and diastolic blood pressure (1.1 mmHg; 95% CI - 4.6 + 2.4 mmHg) were not significant with P values of 0.6 and 0.7 respectively. Compliance was 98.2% for CDR and 94.7% for MD + HCT (P = 0.02). Unusual sleepiness occurred more frequently in the MD arm (P less than 0.01). Thirteen patients chose to continue on CDR, 2 on MD + HCT and 3 had no preference (P = 0.005). CDR is similar in antihypertensive effect to MD + HCT but is better tolerated with fewer withdrawals, fewer adverse effects, better compliance and has more patients electing to continue taking it. 相似文献