全文获取类型
收费全文 | 2228篇 |
免费 | 129篇 |
国内免费 | 115篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 66篇 |
妇产科学 | 45篇 |
基础医学 | 234篇 |
口腔科学 | 47篇 |
临床医学 | 248篇 |
内科学 | 371篇 |
皮肤病学 | 28篇 |
神经病学 | 243篇 |
特种医学 | 372篇 |
外科学 | 282篇 |
综合类 | 56篇 |
预防医学 | 137篇 |
眼科学 | 105篇 |
药学 | 150篇 |
中国医学 | 6篇 |
肿瘤学 | 54篇 |
出版年
2021年 | 23篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 34篇 |
2017年 | 27篇 |
2016年 | 24篇 |
2015年 | 44篇 |
2014年 | 53篇 |
2013年 | 83篇 |
2012年 | 79篇 |
2011年 | 106篇 |
2010年 | 87篇 |
2009年 | 81篇 |
2008年 | 89篇 |
2007年 | 146篇 |
2006年 | 107篇 |
2005年 | 79篇 |
2004年 | 79篇 |
2003年 | 62篇 |
2002年 | 68篇 |
2001年 | 78篇 |
2000年 | 75篇 |
1999年 | 62篇 |
1998年 | 66篇 |
1997年 | 53篇 |
1996年 | 54篇 |
1995年 | 51篇 |
1994年 | 44篇 |
1993年 | 45篇 |
1992年 | 55篇 |
1991年 | 51篇 |
1990年 | 42篇 |
1989年 | 42篇 |
1988年 | 49篇 |
1987年 | 33篇 |
1986年 | 25篇 |
1985年 | 36篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1973年 | 11篇 |
1971年 | 12篇 |
1970年 | 11篇 |
1958年 | 19篇 |
排序方式: 共有2472条查询结果,搜索用时 0 毫秒
11.
Knee joint hyaline cartilage defects: a comparative study of MR and anatomic sections. 总被引:8,自引:0,他引:8
J Hodler M J Berthiaume M E Schweitzer D Resnick 《Journal of computer assisted tomography》1992,16(4):597-603
The value of routinely used MR sequences in the detection of focal changes of femorotibial articular cartilage was studied. T1-weighted, proton density, and T2-weighted SE as well as gradient echo images were acquired in 20 cadaveric knees (56-88 years old, mean 73.8 years). Three hundred five coronal and sagittal (3 mm) anatomic sections were prepared, and 82 areas of cartilage defects were identified. Initially, in an unblinded fashion, correlation of MR scans and anatomic sections was performed. Fifty-nine lesions (72.0%) were detectable on T1-weighted images, 57 (70.0%) with meniscal windowing, 49 (60.0%) on proton density images, 56 (68.3%) on T2-weighted images, and 54 (65.9%) on gradient echo images. Sixty-eight (83.0%) were visible on at least one type of imaging sequence. Most defects presented as a focus of abnormal signal. Subsequently, images of a subset of 35 pathologic and 35 normal cartilage surfaces were blindly evaluated by two osteoradiology fellows. Sensitivity was 71.4% for the detection of focal cartilage changes, specificity was 68.6%, and accuracy was 70.0%. We conclude that the value of those MR sequences that are routinely used in the analysis of internal derangements of the knee in the detection of focal defects of the hyaline cartilage is limited. 相似文献
12.
13.
14.
There is significant alteration of airway calibre after deep inhalation (DI). An increase of airway calibre has been evidenced in children in case of mild asthmatic obstruction and after a positive response to methacholine or exercise challenge. Such an increase is blunted in the presence of a moderate to severe asthmatic airway obstruction and no bronchodilatory effect of DI has been found in infants. Bronchial hyperreactivity and airway inflammation strongly influence post-DI alterations of bronchomotor tone. Airways and lung parenchyma are interdependent but both exhibit imperfect elasticity. Hysterisis characterizes imperfect elasticity of pressure-volume relationship. The mechanical theory of relative hysteresis between airway and lung parenchyma is the main mechanism implicated in the induced changes of airway calibre. DI may influence results of lung function testing in children. The technique may be of interest to increase sensibility of routine lung function testing in children. 相似文献
15.
The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament. 总被引:3,自引:0,他引:3
Magnetic resonance (MR) imaging has shown that tears of the anterior cruciate ligament (ACL) are frequently accompanied by meniscal and osseous injuries. Abnormalities of the cartilage overlying the lateral femoral condylopatellar sulcus (notch) also have been noted during arthrotomy of ACL-deficient knees. In this study, the appearance of this sulcus on MR images and the depth of the sulcus on conventional radiographs are compared in patients with normal and torn ACLs to determine whether a deep sulcus is a useful indirect sign of a torn ACL. In 62 patients with clinically and/or arthroscopically confirmed normal ACLs, the mean depth of the lateral femoral sulcus was 0.45 mm (range, 0.0-1.2 mm) compared with 0.89 mm (range, 0.0-5.0 mm) in 41 patients with clinically and/or arthroscopically confirmed ACL tears (significant at the 5% level). No patient with a normal ACL had a sulcus greater than 1.2 mm in depth. A sulcus deeper than 1.5 mm is equivalent to 3 standard deviations above the mean and was a reliable indirect sign of a torn ACL. 相似文献
16.
P Schweitzer 《American heart journal》1992,124(4):1121-1126
17.
Twelve healthy subjects participated in three daytime work periods, in a double-blind repeated measures Latin square design. Subjects received cetirizine (10 mg), hydroxyzine (25 mg), or placebo at 0800. Performance was measured each day during eight 50-minute test periods on a simulated assembly line task between 0830 and 1700. Before entry into the study, subjects were trained to a minimum 80% correction rate on the performance task. Performance decrements were consistently associated with hydroxyzine but not with cetirizine. Subjects made fewer correct responses with hydroxyzine compared with both cetirizine and placebo. Subjectively, participants reported feeling sleepier and performing worse during the hydroxyzine condition than following placebo. Cetirizine, however, did not differ from the other two conditions on self-assessments of alertness or performance. These findings support the hypothesis that objective measures of human functioning are more specific than are subjective measures. 相似文献
18.
C Schweitzer L T T Vu Y T Nguyen C Choné B Demoulin F Marchal 《The European respiratory journal》2006,28(1):89-95
The bronchomotor effects of a deep inhalation (DI) may provide relevant information about the mechanisms of exercise-induced airway obstruction in children and may be assessed by respiratory conductance (Grs) measured using the forced oscillation technique. The aims of the present study were to assess the effect of DI on Grs after exercise in relationship to the lung function response to exercise. Grs at 12 Hz using a head generator and spirometric data were measured in 62 children suspected of asthma before and 5 min after a 6-min free run. After exercise, Grs was significantly increased by DI in 38 subjects, who also showed larger Grs and forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) responses to exercise than the 24 nonresponders. Stepwise regression indicated significant correlation between the response of Grs to DI and both Grs and FEV1/FVC responses to exercise. The data are consistent with exercise-induced bronchoconstriction being reversed by deep inhalation. 相似文献
19.
G van Servellen C E Lewis B Leake S O Schweitzer 《The Journal of the Association of Nurses in AIDS Care》1991,2(3):29-39
The authors assessed patients' satisfaction with their nursing care in seven hospitals. Five of the hospitals utilized the special care unit (SCU) method of delivering care to AIDS or oncology patients; three had SCUs for AIDS patients. All seven of the hospitals had integrated units (IUs) where general medical, oncology, and/or AIDS patients were received in various proportions. Satisfaction with nursing care was measured with the Risser Patient Satisfaction Instrument. Patient satisfaction with nursing care was shown to be a function of delivery method; AIDS and oncology patients on SCUs expressed greater satisfaction with their care than medical, oncology, or AIDS patients on IUs (p less than .001). Patient satisfaction with nursing care was greater among whites than nonwhites. Also, some major sociodemographic and case mix variables, such as age, employment status, and diagnosis, were not associated with patient satisfaction directly; in other instances, the associations initially seen did not hold when delivery method (SCU vs. IU) and race were controlled for in a linear regression analysis. 相似文献
20.
Background. Keratinizing odontogenic cysts of the mandible commonly have an aggressive clinical course, marked by multiple recurrences. Primary intraosseus carcinoma (PIOC) of the mandible is rare, and when it occurs it is often found to be arising in or closely associated with some type of cystic structure. Methods. A patient with squamous cell carcinoma arising from an odontogenic keratocyst is studied clinically, radiographically, and pathologically. Results. The patient who was documented to have an odontogenic keratocyst, 1 year later had a squamous carcinoma removed from the recurrent cyst. Conclusion. We report the occurrence of squamous cell carcinoma arising from a recurrent odontogenic keratocyst, which has not previously been documented in the literature. The literature on this subject is reviewed. © 1994 John Wiley & Sons, Inc. 相似文献