全文获取类型
收费全文 | 4947篇 |
免费 | 611篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 100篇 |
妇产科学 | 310篇 |
基础医学 | 619篇 |
口腔科学 | 208篇 |
临床医学 | 1218篇 |
内科学 | 773篇 |
皮肤病学 | 75篇 |
神经病学 | 546篇 |
特种医学 | 378篇 |
外科学 | 538篇 |
综合类 | 69篇 |
一般理论 | 2篇 |
预防医学 | 277篇 |
眼科学 | 31篇 |
药学 | 234篇 |
中国医学 | 5篇 |
肿瘤学 | 186篇 |
出版年
2023年 | 50篇 |
2021年 | 43篇 |
2020年 | 56篇 |
2019年 | 61篇 |
2018年 | 113篇 |
2017年 | 145篇 |
2016年 | 130篇 |
2015年 | 159篇 |
2014年 | 182篇 |
2013年 | 215篇 |
2012年 | 185篇 |
2011年 | 209篇 |
2010年 | 184篇 |
2009年 | 182篇 |
2008年 | 183篇 |
2007年 | 204篇 |
2006年 | 200篇 |
2005年 | 173篇 |
2004年 | 159篇 |
2003年 | 187篇 |
2002年 | 163篇 |
2001年 | 163篇 |
2000年 | 122篇 |
1999年 | 163篇 |
1998年 | 138篇 |
1997年 | 141篇 |
1996年 | 145篇 |
1995年 | 115篇 |
1994年 | 93篇 |
1993年 | 76篇 |
1992年 | 99篇 |
1991年 | 91篇 |
1990年 | 76篇 |
1989年 | 111篇 |
1988年 | 98篇 |
1987年 | 68篇 |
1986年 | 76篇 |
1985年 | 78篇 |
1984年 | 40篇 |
1983年 | 38篇 |
1982年 | 37篇 |
1981年 | 30篇 |
1980年 | 27篇 |
1979年 | 30篇 |
1977年 | 26篇 |
1976年 | 24篇 |
1975年 | 32篇 |
1974年 | 24篇 |
1973年 | 22篇 |
1972年 | 23篇 |
排序方式: 共有5585条查询结果,搜索用时 62 毫秒
1.
2.
The difficulty of diagnosing NCSE in clinical practice; external validation of the Salzburg criteria
Rianne J. M. Goselink Jeroen J. van Dillen Marjolein Aerts Johan Arends Charlotte van Asch Inge van der Linden Jaco Pasman Christiaan G. J. Saris Machiel Zwarts Nens van Alfen 《Epilepsia》2019,60(8):e88-e92
To improve the diagnostic accuracy of electroencephalography (EEG) criteria for nonconvulsive status epilepticus (NCSE), external validation of the recently proposed Salzburg criteria is paramount. We performed an external, retrospective, diagnostic accuracy study of the Salzburg criteria, using EEG recordings from patients with and without a clinical suspicion of having NCSE. Of the 191 EEG recordings, 12 (12%) was classified as an NCSE according to the reference standard. In the validation cohort, sensitivity was 67% and specificity was 89%. The positive predictive value was 47% and the negative predictive value was 95%. Ten patients in the control group (n = 93) were false positive, resulting in a specificity of 89.2%. The interrater agreement between the reference standards and between the scorers of the Salzburg criteria was moderate; disagreement occurred mainly in patients with an epileptic encephalopathy. The Salzburg criteria showed a lower diagnostic accuracy in our external validation study than in the original design, suggesting that they cannot replace the current practice of careful weighing of both clinical and EEG information on an individual basis. 相似文献
3.
D Van Neste† RM Trüeb‡ 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):578-583
BACKGROUND: Computer-assisted image analysis has been proposed for human hair growth studies. METHODS: The performances of Trichoscan, a commercially available automated system combining epiluminiscence microscopy with digital image analysis, developed for office-based hair growth measurements, have been evaluated comparatively on the same skin sites using standardized photographic equipment and calibrated processing for contrast-enhanced phototrichogram (CE-PTG) analysis. This reference method has been validated with scalp biopsies and histological examination of serial sectioning. RESULTS: Besides edge effects, hair fibres escaped the Trichoscan analysis for various reasons including, but not limited to, thickness, pigmentation, closeness and crossing. CONCLUSION: Most of these problems have been identified in the late 1980s and remain largely unsolved by the processing software that was evaluated in 2004. Therefore claims promoting the Trichoscan method for accurate hair measurements in clinical trials on scalp and body hair are not supported by the present investigation. The speed at which the analysis is performed is outweighed by the errors in signal detection. Therefore we suggest that improvements must be clearly documented before Trichoscan is established for quantified diagnostic purposes and detailed hair cycle monitoring during hair trials. 相似文献
4.
5.
To improve the appropriateness and efficiency of diagnostic serological tests and subsequent antibiotic treatment, clinical data from 102 patients with unclassified arthritis were analysed to investigate whether the presence of positive IgG antibodies to Borrelia burgdorferi could be predicted. The clinical data were blindly ranked from 1 to 4 (1, Lyme arthritis unlikely; 4, Lyme arthritis very likely). Antibodies to B burgdorferi were positive in nine of 102 patients (9%). Six of 15 (40%) patients with rank numbers 3 and 4 were positive for antibodies to B burgdorferi, in contrast with only three of 87 (3%) patients with rank numbers 1 and 2. The likelihood ratio of positive Lyme serology for patients ranked 3 and 4 was 12.0, for patients ranked 2 to 4, 4.5, and for patients with arthritis of the knee, 3.0. These likelihood ratios were associated with a post-test probability of 55, 30, and 20% respectively. The clinical history in patients with unclassified arthritis can largely predict the presence of antibodies to B burgdorferi. The absolute value of a likelihood ratio can be a contributing factor in deciding to request tests for antibodies to B burgdorferi in patients with unclassified arthritis. 相似文献
6.
7.
J M Debets R Kampmeijer M P van der Linden W A Buurman C J van der Linden 《Critical care medicine》1989,17(6):489-494
Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients. 相似文献
8.
9.
Toe temperature versus transcutaneous oxygen tension monitoring during acute circulatory failure 总被引:1,自引:0,他引:1
Measurements of toe temperature and transcutaneous PO2 (PtcO2) have been both suggested for non-invasive assessment of peripheral blood flow in acute circulatory failure. The underlying
principle of the two methods is that cutaneous vasoconstriction occurs early when tissue perfusion is altered. In 15 patients,
we compared the two measurements during cardiogenic shock (27 measurements) or septic shock (29 measurements). Toe-ambiant
temperature gradient and PtcO2 correlated well together (r=0.66, p(0.001) especially in hyperkinetic septic shock (r=0.79, p(0.001). In cardiogenic shock, toe-ambiant temperature correlated well with cardiac index (r=0.63), stroke index (r=0.64) and oxygen transport (r=0.65), and these correlations were stronger than for PtcO2. In septic shock, both techniques were poor indicators of blood flow indexes but PtcO2 rather correlated with arterial pressure (r=0.66) and left ventricular work (r=0.66). Trend evaluation of data revealed in cardiogenic shock that the increase in toe temperature usually preceded the increase
in PtcO2. Since measurement of PtcO2 is technically more complicated, correlates less well with standard hemodynamic parameters and later reflects cardiovascular
improvement, it has no advantage over measurement of toe temperature in circulatory shock. In cardiogenic shock, measurements
of toe temperature can reliably track cardiac output changes. In septic states, however, non-invasive assessment of skin perfusion
is of limited interest. 相似文献
10.
J L Vincent P Van der Linden M Domb S Blecic G Azimi A Bernard 《Anesthesia and analgesia》1987,66(6):565-571
The hemodynamic effects of dopamine and dobutamine (at doses of 6 micrograms X kg-1 X min-1) were compared during fluid resuscitation from septic shock induced by endotoxin (3 mg/kg) in the dog. In the first part of the study, when a standard amount of saline solution was infused (in 24 dogs), dopamine infusion resulted in higher cardiac filling pressures than did dobutamine infusion, whereas dobutamine infusion resulted in higher cardiac output. In the second part of the study, when fluid infusion was titrated to maintain pulmonary artery balloon-occluded pressure at constant level (in 24 dogs), the total amount of fluids was significantly greater with dobutamine than when dopamine was used (109 +/- 13 vs 71 +/- 10 ml/kg). The combination of dobutamine with fluids resulted in significantly greater stroke volume (39.6 +/- 3.8 vs 21.0 +/- 4.0 ml, P less than 0.05) and oxygen consumption (194 +/- 18 vs 144 +/- 8 ml/min, P less than 0.05). The different effects of dopamine and dobutamine on cardiac filling pressures can be due to differences in effects on myocardial contractility, ventricular afterload, and cardiac compliance. This experimental study indicates that when fluid therapy is combined with adrenergic agents in resuscitation from septic shock, dobutamine can be associated with higher cardiac output and oxygen transport and can result in higher tissue oxygen consumption than dopamine. 相似文献