全文获取类型
收费全文 | 96063篇 |
免费 | 8102篇 |
国内免费 | 2573篇 |
专业分类
耳鼻咽喉 | 859篇 |
儿科学 | 2003篇 |
妇产科学 | 1201篇 |
基础医学 | 6806篇 |
口腔科学 | 3103篇 |
临床医学 | 12441篇 |
内科学 | 11770篇 |
皮肤病学 | 2603篇 |
神经病学 | 5135篇 |
特种医学 | 1778篇 |
外国民族医学 | 10篇 |
外科学 | 6708篇 |
综合类 | 15742篇 |
现状与发展 | 9篇 |
一般理论 | 26篇 |
预防医学 | 9448篇 |
眼科学 | 1306篇 |
药学 | 13183篇 |
568篇 | |
中国医学 | 7939篇 |
肿瘤学 | 4100篇 |
出版年
2024年 | 1077篇 |
2023年 | 1967篇 |
2022年 | 3069篇 |
2021年 | 4778篇 |
2020年 | 5032篇 |
2019年 | 3905篇 |
2018年 | 3611篇 |
2017年 | 3965篇 |
2016年 | 3883篇 |
2015年 | 3578篇 |
2014年 | 6314篇 |
2013年 | 7060篇 |
2012年 | 5901篇 |
2011年 | 6084篇 |
2010年 | 4857篇 |
2009年 | 4372篇 |
2008年 | 4319篇 |
2007年 | 4450篇 |
2006年 | 3771篇 |
2005年 | 3303篇 |
2004年 | 2770篇 |
2003年 | 2455篇 |
2002年 | 1966篇 |
2001年 | 1695篇 |
2000年 | 1406篇 |
1999年 | 1224篇 |
1998年 | 999篇 |
1997年 | 969篇 |
1996年 | 849篇 |
1995年 | 772篇 |
1994年 | 719篇 |
1993年 | 534篇 |
1992年 | 609篇 |
1991年 | 538篇 |
1990年 | 445篇 |
1989年 | 452篇 |
1988年 | 433篇 |
1987年 | 386篇 |
1986年 | 301篇 |
1985年 | 338篇 |
1984年 | 267篇 |
1983年 | 199篇 |
1982年 | 222篇 |
1981年 | 176篇 |
1980年 | 154篇 |
1979年 | 111篇 |
1978年 | 90篇 |
1977年 | 80篇 |
1976年 | 65篇 |
1975年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Anita MacDonald Dr Sandra Warrington Chairman Professional Development Committee 《Journal of human nutrition and dietetics》1990,3(2):71-77
At the present time, there are many fundamental issues coming from the Department of Health or from other national organizations, which will have an effect on the future development of the dietetic profession. The British Diatetic Association (BDA) Professional Development Committee will consider these issues, as and when appropriate, and will publish the information in the form of Briefing Papers.
The first Briefing Paper on 'Quality Assurance' was published by the BDA in November 1989. The second on 'Measuring clinical outcome' is published below. In each case the opinion of BDA members and specialist groups has been sought and the Professional Development Committee wishes to thank individuals and the specialist groups for their comments.
The Briefing Papers are intended to provide information and promote discussion among the membership. I would welcome further comments from readers, which may be directed to the British Dietetic Association Office. 相似文献
The first Briefing Paper on 'Quality Assurance' was published by the BDA in November 1989. The second on 'Measuring clinical outcome' is published below. In each case the opinion of BDA members and specialist groups has been sought and the Professional Development Committee wishes to thank individuals and the specialist groups for their comments.
The Briefing Papers are intended to provide information and promote discussion among the membership. I would welcome further comments from readers, which may be directed to the British Dietetic Association Office. 相似文献
22.
23.
W. N. Charman 《Ophthalmic & physiological optics》2006,26(1):5-12
In the Cardiff acuity test, simple pictures on an otherwise neutral grey card are defined by borders consisting of a relatively broad white band flanked by black bands each half the width of the white band. Higher levels of acuity correspond to the ability to detect figures defined by narrower borders, the figure size remaining constant. It is sometimes implied that the acuity limit corresponding to each card can be equated with different levels of grating resolution, the total width of the border corresponding to the overall grating period. It is shown that although the spatial frequency spectra of the Cardiff figures, like those of other vanishing optotypes, lack very low-frequency components, they have a complex two-dimensional form. The figures have wide spatial bandwidth and no well-defined discrete frequency components. As a result, the relationship between measured Cardiff and grating acuity will vary somewhat, depending upon the particular optical, neural or other deficits of the individual being tested. 相似文献
24.
Martine Hascoët Michel Bourin Jacques Bradwejn 《Progress in neuro-psychopharmacology & biological psychiatry》1991,15(6):825-840
1. The mechanism of action of drugs might change according to the test used. Several noradrenergic drugs were tested in order to understand their implication in the mobility tests.
2. It was found that clonidine, an Alpha 2 agonist, acted differently according to the tast used. It provoked sedation in spontaneous activity test, and anti-immobility effects in the other tests.
3. Tall suspension test is able to show the double acting of clonidine.
4. Idazoxan might act either as an alpha 2 antagonist or as partial alpha 2 agonist. TST shown the unexpected partial alpha agonist effect of the molecule.
5. Forced swimming test is more specific for predicting antidepressant activity than tail suspension test which is close to a spontaneous activity model. 相似文献
25.
JOHN P. BOURKE LYNNE HOWELL ALAN MURRAY WILLIAM E. HILL J. CAMPBELL COWAN KEVIN BEATT JOAN ERRINCTON STUART JAMESON RONALD G. GOLD 《Pacing and clinical electrophysiology : PACE》1989,12(8):1419-1425
A randomized prospective study was undertaken to compare the electrical performances of three permanent, endocardial, tined pacing leads with different electrode designs--sintered platinum, vitreous carbon, and porous carbon. Ninety-nine patients received one of the leads (S80 31; 423S 32; S100 36). Acute R wave amplitude and ST elevation of the native endocardial electrogram, voltage threshold, impedance, and current flow at four pulse durations (0.25-1.0 msec) were measured. Voltage thresholds were measured noninvasively at each of four pulse durations at 2 days and 1, 3, and 6 months after implantation. No significant differences were found in sensing properties, or current flow at threshold at 0.5 msec pulse duration. The 423S lead had a significantly higher impedance at threshold and both a higher impedance and lower current flow at 5 V. No significant differences in threshold voltages were found between the three leads at any pulse duration, at any of the assessed times after implantation. Six-month thresholds for the S80, 423S, and S100 leads were 1.18 +/- 0.35, 1.17 +/- 0.29, and 1.06 +/- 0.38 V respectively at 0.5 msec pulse duration. Differences between 'high performance' pacing leads need to be of a greater order of magnitude before they can be exploited to give any real clinical advantage to patients. 相似文献
26.
27.
K. W. Stephen J. I. Russell S. L. Creanor C. K. Burchell 《Community dentistry and oral epidemiology》1987,15(2):90-94
Fibre optic transillumination (FOTI) has been employed during the course of a 3-yr clinical dentifrice trial which initially involved 3003 children. At the initial examination, a subgroup of 813 13-yr-olds, and at the following annual visit, 2247 14-yr-olds, were examined using a 150 W lamp and 0.5 mm diameter probe. Routine clinical and radiographic examinations were performed separately. Compared to the clinical scores for anterior teeth, FOTI detected an additional 64% of interproximal lesions at the first visit while, for the larger number of children at the second visit, the increase in lesion detection level using FOTI was 37%. For the posterior teeth the comparable figure at the second examination was 92%. When FOTI data were compared to radiographic data for more than 52,000 posterior interproximal surfaces, FOTI could only detect 17% of radiographic Grade 2 lesions and 48% Grade 3 lesions. Thus any assumption that FOTI diagnoses may be a substitute for bitewing radiography appears premature. 相似文献
28.
29.
S. M. Fuchs C. Heinemann S. Schliemann-Willers H. Härtl J. W. Fluhr P. Elsner 《Skin research and technology》2006,12(4):223-227
OBJECTIVE: In the present study, we evaluated the anti-inflammatory activity of Poria cocos (PoCo) on experimentally induced irritant contact dermatitis (ICD) in a repeated sodium lauryl sulphate (SLS) irritation model. METHODS: The anti-irritative effect of PoCo was evaluated with a visual score and quantified by non-invasive bioengineering methods, namely chromametry and transepidermal water loss. Three concentrations of PoCo in base cream DAC (amphiphilic emollient; German pharmacopoeia) were tested in a 4-day repetitive irritation test using SLS. RESULTS: A statistically significant anti-inflammatory activity was observed for PoCo by all three methods when applied in parallel to the induction period of ICD. Application of PoCo after induction of ICD once a day for 5 days, starting just at the end of 4 days, was without any effect. CONCLUSION: An anti-inflammatory efficacy of PoCo on the elicitation phase of the ICD induced by repeated SLS test could be observed and quantified by three independent, non-invasive biophysical assessment parameters. This effect can be explained by its influence on pro-inflammatory enzymes, namely phospholipase A2. 相似文献
30.
V Schleyer† S Radakovic-Fijan‡ S Karrer† T Zwingers§ A Tanew‡ M Landthaler† RM Szeimies† 《Journal of the European Academy of Dermatology and Venereology》2006,20(7):823-828
BACKGROUND: Based on good results in the treatment of superficial skin tumours, since the early 1990s topical photodynamic therapy with aminolaevulinic acid (ALA PDT) has been used for disseminated, inflammatory dermatoses including psoriasis. However, there is still a lack of well-documented trials. OBJECTIVE: A prospective randomized, double-blind phase I/II intrapatient comparison study was conducted in 12 patients to investigate whether topical ALA PDT is an effective treatment for chronic plaque-type psoriasis. METHODS: In each patient three psoriatic plaques were randomly treated with a light dose of 20 J/cm(2) and 0.1%, 1% and 5% ALA, respectively. Treatment was conducted twice a week until complete clearance or for a maximum of 12 irradiations. Therapeutic efficacy was assessed by weekly determination of the psoriasis severity index (PSI). RESULTS: The mean percentage improvement was 37.5%, 45.6% and 51.2% in the 0.1%, 1% and 5% ALA-treated groups, respectively. Irradiation had to be interrupted several times because of severe burning and pain sensation. CONCLUSION: Topical ALA PDT did not prove to be an appropriate treatment option for plaque-type psoriasis due to disappointing clinical efficacy, the time-consuming treatment procedure and its unfavourable adverse event profile. 相似文献