全文获取类型
收费全文 | 7094篇 |
免费 | 526篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 188篇 |
妇产科学 | 64篇 |
基础医学 | 1315篇 |
口腔科学 | 172篇 |
临床医学 | 506篇 |
内科学 | 1182篇 |
皮肤病学 | 193篇 |
神经病学 | 934篇 |
特种医学 | 315篇 |
外科学 | 930篇 |
综合类 | 76篇 |
一般理论 | 1篇 |
预防医学 | 424篇 |
眼科学 | 187篇 |
药学 | 536篇 |
中国医学 | 4篇 |
肿瘤学 | 555篇 |
出版年
2022年 | 37篇 |
2021年 | 111篇 |
2020年 | 71篇 |
2019年 | 98篇 |
2018年 | 117篇 |
2017年 | 89篇 |
2016年 | 110篇 |
2015年 | 132篇 |
2014年 | 160篇 |
2013年 | 201篇 |
2012年 | 362篇 |
2011年 | 333篇 |
2010年 | 219篇 |
2009年 | 203篇 |
2008年 | 311篇 |
2007年 | 333篇 |
2006年 | 333篇 |
2005年 | 358篇 |
2004年 | 351篇 |
2003年 | 354篇 |
2002年 | 340篇 |
2001年 | 184篇 |
2000年 | 154篇 |
1999年 | 163篇 |
1998年 | 133篇 |
1997年 | 82篇 |
1996年 | 78篇 |
1995年 | 81篇 |
1994年 | 61篇 |
1993年 | 73篇 |
1992年 | 149篇 |
1991年 | 119篇 |
1990年 | 116篇 |
1989年 | 116篇 |
1988年 | 105篇 |
1987年 | 86篇 |
1986年 | 92篇 |
1985年 | 94篇 |
1984年 | 75篇 |
1983年 | 59篇 |
1982年 | 54篇 |
1981年 | 50篇 |
1980年 | 61篇 |
1979年 | 67篇 |
1977年 | 50篇 |
1976年 | 52篇 |
1975年 | 43篇 |
1974年 | 37篇 |
1973年 | 46篇 |
1972年 | 39篇 |
排序方式: 共有7631条查询结果,搜索用时 116 毫秒
121.
Gerd Geerling Norbert Koop Andreas Tüngler Ralf Brinkmann Christopher Wirbelauer Reginald Birngruber Horst Laqua 《Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft》1999,96(5):306-311
Purpose: Pulsed holmium lasers are currently used to correct hyperopia by means of laser thermokeratoplasty (LTK). Series of μs laser
pulses are applied with a high repetition rate to induce shrinkage of corneal collagen fibers. The pulsed energy application
results in intrastromal temperature peaks of up to 200 °C. A continuously emitting laser diode can – as we demonstrated recently
in an invivo study on minipigs – be used for LTK and may be of advantage because the temperature rise is more steady. The
aim of this study was to examine the safety, amount, and stability of hyperopic correction of diode LTK on blind human eyes.
Methods: We used a laserdiode that was set to continuously emit light at λ = 1.854 μm/μa = 1.04 mm–1(group I, n = 4) or 1.87 μm/μa = 1.92 mm–1 (group II, n = 4). Radiation energy was 100 to 150 mW for 10 s per coagulation. Eight coagulations on a single ring (group I) and 16 coagulations
on a double ring (group II) diameter were applied in the cornea concentric to the entrance pupil by means of a vacuum-fixed
application mask (group I = conjunctival fixation; group II = corneal fixation) and a handpiece with a focusing optic. Preoperatively
as well as 1 week, 1, 2, 3, 6 12 and 18 months postoperative ophthalmologic controls were performed and the corneal refractive
power was measured.
Results: In group I initial refractive changes of up to + 4.9 D were achieved (1 week postoperative). However, due to the great penetration
depth of the laser irradiation, large endothelial defects resulted beneath the stromal coagulations. In group II an initial
refractive change of up to + 6.8 D was achieved and as a result of the reduced penetration depth, the endothelial cell damage
was much reduced. Partial regression of the refractive effect occured in all subjects, which continued in higher refractive
changes during the 2nd postoperative year. The refractive effect at 12 months was + 0.6 to + 1.5 D in group I and + 0.9 to + 5.7 D in group II.
At 12 months the induced astigmatism was 0.5 to 2.2 D in group I and 0.3 to 1.6 D in group II. No serious adverse effects
were noticed.
Conclusion: A continously emitting laser diode working at a wavelength of 1.87 μm can be used to correct hyperopia by means of LTK safely
and effectively. Regression occurs predominantly in the first 6 postoperative months. Further studies must be conducted to
determine the importance of patient inherent parameters such as age in establishing a nomogram.
相似文献
122.
The short term effects of a dental health educational video on adolescents' knowledge, attitude and future behaviour were assessed. Results showed a large effect on knowledge and a small effect on five attitudinal aspects. No effects were found on future behaviour. 相似文献
123.
Two idiopathic thrombi loosely attached to the left ventricular wall were detected by dynamic three-dimensional echocardiography. Because the thrombi were shown to be lobulated and extremly mobile, urgent surgical treatment was mandatory. Three-dimensional image reconstruction enhanced appreciation of left ventricular thrombi by enabling accurate imaging of the spatial relationship between the thrombus, the myocardial wall, and the valvular apparatus, so that the most advantageous surgical access could be chosen. 相似文献
124.
Somatization in frequent attenders of general practice 总被引:5,自引:0,他引:5
P. J. M. Portegijs F. G. van der Horst I. M. Proot H. F. Kraan N. C. H. F. Gunther J. A. Knottnerus 《Social psychiatry and psychiatric epidemiology》1996,31(1):29-37
The DSM-III-(R) definition of somatization disorder is too restrictive for use in general practice. A more comprehensive definition, the somatic symptom index (SSI) has shown good validity in open populations. However, a definition has to differentiate validlywithin a population of frequent attenders to be a useful diagnostic instrument in general practice. We studied a threshold of five complaints (nearly identical to the SSI) in 80 Dutch general practice patients. Patients were selected on age (20–44 years), history of back, neck or abdominal complaints, and on frequency of consultation—at least 12 consultations in the previous 3 years, corrected for consultations with compelling somatic reason for encounter. Prevalence of somatization in this group was 45%. Women had a 2 times higher risk of somatization. A relation with age was not found. Somatization was related to depressive complaints (relative risk 2.5) and probably also to anxiety. Somatizing patients consulted their general practitioner more often and had more health problems (especially psychic problems) than non-somatizers. These results support the validity of this definition. The distinction between our definition of somatization and somatization defined as a symptom of psychiatric (e.g. depressive or anxiety) disorder is emphasized. 相似文献
125.
Heinrich Heimann Norbert Bornfeld Wilko Friedrichs Horst Helbig Ulrich Kellner Ayman Korra Michael H. Foerster 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1996,234(9):561-568
Background: Pars planta vitrectomy has evolved as an alternative method in the treatment of more complicated rhegmatogenous retinal detachments. We report a series of patients who underwent primary vitrectomy with gas tamponade without the use of additional scleral buckling. Methods: A retrospective study of 53 patients with a follow-up of 6–45 months (mean 17.8 months) was carried out. Preoperative findings included unusual, multiple or large breaks, vitreous haemorrhage, proliferative vitreoretinopathy and bullous retinal detachment. Preoperative visual acuity was between light perception and 1.0, with 30% (16/53) of patients with 0.4 or better. Results: Retinal reattachment was achieved in 64% of cases (34/53) with one and in 92% (49/53) with one or more operations. Final visual acuity was between light perception and 1.0, with 41% (22/53) of patients with 0.4 or better. Cataract formation occurred in 86% (37/43) of all patients with a clear lens preoperatively. Macular pucker was noted in 11 % (6/53) and postoperative proliferative vitreoretinopathy causing redetachment in 6% (3/53). Conclusion: With primary vitrectomy, a high final anatomical success rate with few intraoperative complications can be achieved in more complicated forms of rhegmatogenous retinal detachment. The major drawback of the procedure is the high incidence of post-operative cataract formation. 相似文献
126.
Alan W. Partin Stuart R. Criley Eric N.P. Subong Horst Zincke Patrick C. Walsh Joseph E. Oesterling 《The Journal of urology》1996,155(4):1336-1339
Purpose
Age-specific prostate specific antigen (PSA) reference ranges have been suggested to account for the age-dependent nature of the serum PSA concentration. It has been hypothesized that reference ranges of 0 to 2.5 ng./ml. serum PSA (40 to 49 years), 0 to 3.5 ng./ml. (50 to 59 years), 0 to 4.5 ng./ml. (60 to 69 years) and 0 to 6.5 ng./ml. (70 to 79 years) would detect fewer (potentially insignificant) prostate cancers in older men and more (potentially curable) cancers in younger men.Materials and Methods
To investigate the pathological stage of tumors that would be affected by the use of age-specific PSA reference ranges, we reviewed the medical records for 4,597 men with clinically localized (stage T1c, T2 or T3a) prostate cancer, with an average age of 62 plus/minus 7 years (range 38 to 76), who underwent radical prostatectomy between 1984 and 1994 at our institutions. Favorable pathological results were defined as organ-confined disease or capsular perforation with a Gleason score of less than 7, and unfavorable pathological results were defined as capsular perforation with a Gleason score of 7 or more, seminal vesicle invasion or lymph node involvement.Results
Overall, 18 percent of the men had PSA levels less than the standard PSA reference range (4.0 ng./ml.) compared to 22 percent when using the age-specific ranges. There were 74 more cancers detected in men younger than 60 years with the use of age-specific ranges, of which 81 percent had favorable pathological results. Among the men 60 years or older, 191 of 252 cancers (76 percent) not detected by using age-specific ranges were of favorable pathological status. Of those cancers not detected in older men with the age-specific ranges less than 3 percent were also stage T1c and 95 percent of these undetected T1c cancers were of favorable pathological status. Age-specific PSA reference ranges increased the potential for detection of prostate cancer by 18 percent in the younger men and decreased the detection by 22 percent in the older men.Conclusions
Among these men with clinically localized prostate cancer, age-specific PSA reference ranges increased the detection of more potentially curable tumors in young men and decreased the detection of less advanced tumors in the older men compared to the standard reference range of 4.0 ng./ml. Among older men with nonpalpable (stage T1c) tumors age-specific PSA reference ranges would have detected fewer tumors. However, 95 percent of these “missed” tumors would have had favorable pathological findings. 相似文献127.
Udo Kaisers Dirk Pappert Jan M. Langrehr Horst Undi Peter Neuhaus Rolf Rossaint 《Transplant international》1996,9(3):214-220
The purpose of this study was to determine the effects of vasoactive treatment with dopamine (DO), dopexamine (DX), and dobutamine (DOB) on hemodynamics, oxygen transport and hepatic venous oxygen saturation (SvhO2) after orthotopic liver transplantation (OLT). A pulmonary artery catheter was inserted into the right hepatic vein of 17 OLT patients. Timed infusion of DO, DX, and DOB was performed at the following rates: DO at 4 and 8 g/kg per minute, and DOB at 5 and 10 g/kg per minute. Hemodynamics, oxygen transport variables, and SvhO2 were assessed. Each catecholamine induced a significant increase in cardiac index, oxygen delivery, and SvhO2. Mean arterial pressure was increased during DO and DOB, but significantly reduced during DX. Each inotrope increased oxygen delivery in parallel with SvhO2, suggesting a corresponding increase in hepatic oxygen supply. Therefore, it appears that each vasoactive drug may be utilized in OLT patients to provide oxgen delivery without impairment of splanchnic oxygenation. 相似文献
128.
Hemodynamic assessment of aorto-iliac occlusive disease is necessary for successful arterial reconstruction of the legs. Various methods have been proposed and the "pull-through" intra-arterial pressure measurement method is accepted as the best standard. The pressure readings, however, seemed to depend on the intraluminal position of the catheter. To explain these observations and make a comparison between the Doppler method and the "pull-through" method, we have studied center-line velocity changes at the stenosis throat by Doppler ultrasound, and axial and lateral pressure gradients using pressure transducers, mounted 10 mm and 40 mm downstream of short (4 mm) and long (40 mm) axisymmetric sharp-edged model stenoses having cross sectional reduced areas of 64%, 84%, 91%, and 96%. Axial manometric pressures measured 10 mm after the throat of 84% stenosis were more than twice as high as the lateral pressures. There was no significant difference between axial and lateral pressures measured 40 mm downstream from throat. This pressure distribution has important clinical relevance. Mean and peak pressure gradients for both the Doppler method and manometric measurements were compared. Measurements with Doppler method and manometric measurements, indicated that mean pressure gradients (r = 0.98; SEE = +/- -2.4 mmHg) correlate better than peak pressure gradients (r = 0.90; SEE = +/- 16.5 mmHg). Doppler gradients were higher than manometer gradients. Overestimation was 13% for mean pressure gradients, and ranging from 10% to 150% for peak pressure gradients. Explanation for the difference between mean Doppler and catheter gradient may be the pressure recovery occurring in the relaminarized poststenotic regions. 相似文献
129.
M. Milčinski E. Henze R. Lietzenmayer M. Clausen R. Weller V. Hombach W. E. Adam M. Porenta 《European journal of nuclear medicine and molecular imaging》1991,18(1):17-22
The quantification of myocardial perfusion abnormalities is necessary to allow comparison of repeated studies, especially in the evaluation of the success of medical, interventional or combined treatment in stable coronary artery disease or in evolving myocardial infarction. The purpose of this study was to assess inter-observer reproducibility of tomographic study processing using a semi-automatic quantitative programme. Technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi) was chosen for tomographic imaging of repeated rest-stress studies in patients with stable coronary artery disease. The quantification was performed using a modification of the Cedars polar coding and comparison with the normal data base. The perfusion defects were quantified separately for each standard perfusion area [left anterior descending (LAD), right coronary (RCA) and left circumflex (LCX) arteries] and total area of hypoperfused myocardium. The inter-observer variability for 40 tomographic studies was accomplished. The defects were the largest in the LAD perfusion area (average 19.7% of the normalized LAD supply area) with an inter-observer correlation of 0.84 for this region. The greatest variability was found for the LCX region (r=0.55) and is attributed to a small average perfusion defect (7.1%), only 18 studies having abnormal perfusion in this area. In total, an average 14.3% of the left ventricular myocardium was significantly hypoperfused, and the inter-observer correlation was 0.87. These results show good inter-observer reproducibility using semi-automatic quantitation of perfusion defects. Careful interpretation of smaller defects in the evaluation of treatment results is advised when repeated 99mTc-Sestamibi single photon emission tomography studies are processed by more than one observer.The work was performed at Nuclear Medicine Department in Ulm.
Offprint requests to: M. Milinski 相似文献
130.
Horst D. Köhn Adolf Mostbeck 《European journal of nuclear medicine and molecular imaging》1979,4(1):21-25
Although it is common to perform scintigrams in multiple projections this technique has not yet been generally accepted for kidney scintigraphy. By performing additional lateral scans using an Anger camera and with patients sitting we found at least three advantages:
- Better Visualisation of Kidney Lesions: 7 (13,5%) of 52 cases with lesions could be detected in lateral projection only, in all other cases we obtained better information concerning location and size of lesions.
- Determination of Real Kidney Size: Of 62 patients with kidneys appearing reduced unilaterally in the dorsal projection, additional lateral recordings demonstrated that 24 (39%) seemed diminished because of tilting.
- Better Interpretation of Renograms: Demonstration of different depths of kidneys facilitates interpretation of renograms with different peak heights. Additional lateral scans thus can provide — at least if dorsal recordings are inconclusive — further information.