全文获取类型
收费全文 | 46138篇 |
免费 | 2965篇 |
国内免费 | 1490篇 |
专业分类
耳鼻咽喉 | 736篇 |
儿科学 | 1218篇 |
妇产科学 | 838篇 |
基础医学 | 4340篇 |
口腔科学 | 736篇 |
临床医学 | 4584篇 |
内科学 | 7286篇 |
皮肤病学 | 1874篇 |
神经病学 | 2813篇 |
特种医学 | 1211篇 |
外国民族医学 | 1篇 |
外科学 | 2229篇 |
综合类 | 6246篇 |
现状与发展 | 3篇 |
预防医学 | 5454篇 |
眼科学 | 557篇 |
药学 | 6593篇 |
29篇 | |
中国医学 | 2163篇 |
肿瘤学 | 1682篇 |
出版年
2024年 | 65篇 |
2023年 | 582篇 |
2022年 | 1247篇 |
2021年 | 1788篇 |
2020年 | 1486篇 |
2019年 | 1348篇 |
2018年 | 1458篇 |
2017年 | 1413篇 |
2016年 | 1381篇 |
2015年 | 1516篇 |
2014年 | 2889篇 |
2013年 | 3286篇 |
2012年 | 2816篇 |
2011年 | 3030篇 |
2010年 | 2405篇 |
2009年 | 2260篇 |
2008年 | 2289篇 |
2007年 | 2320篇 |
2006年 | 1954篇 |
2005年 | 1777篇 |
2004年 | 1453篇 |
2003年 | 1264篇 |
2002年 | 1026篇 |
2001年 | 953篇 |
2000年 | 815篇 |
1999年 | 767篇 |
1998年 | 610篇 |
1997年 | 607篇 |
1996年 | 546篇 |
1995年 | 542篇 |
1994年 | 489篇 |
1993年 | 386篇 |
1992年 | 427篇 |
1991年 | 391篇 |
1990年 | 317篇 |
1989年 | 325篇 |
1988年 | 318篇 |
1987年 | 283篇 |
1986年 | 235篇 |
1985年 | 253篇 |
1984年 | 205篇 |
1983年 | 163篇 |
1982年 | 182篇 |
1981年 | 148篇 |
1980年 | 121篇 |
1979年 | 90篇 |
1978年 | 81篇 |
1977年 | 66篇 |
1976年 | 49篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
51.
Patients suffering from semantic dementia provide important constraints on theories of the structure and organisation of semantic memory. In this article we report one such patient, AM, whose progressive deterioration of semantics enables us to address the much-debated issue of whether conceptual structure is hierarchically organised. The hierarchical account predicts that brain damage should impair lower levels of the hierarchy (property information) before affecting higher level (category) information (Warrington and Shallice, Q. J. Exp. Psychol. 1975, 27, 635–657). We evaluate this prediction by repeated testing of AM in two studies—a semantic priming task and a verification task—over an 18 month period, contrasting the progressive deterioration of properties (functional and perceptual) and category relations (category co-ordinates and category labels). Properties were preserved longer than category information, arguing against a hierarchical account of semantic memory. In addition, functional properties were most robust to brain damage, supporting our claim that functional information plays a special role in semantic representations (Durrant-Peatfield et al., Proc. 19th Ann. Conf. of the Cognitive Science Society. Erlbaum, Mahwah, NJ, 1997, pp. 193–198. Tyler et al., Cognitive Neuropsychol. 1997, 14, 511–545). 相似文献
52.
T. O. Klemsdal H. H. Mundal K. Gjesdal 《European journal of clinical pharmacology》1996,51(3-4):227-230
Objective:
We examined the relationship between tolerance development, counterregulatory responses and arterial vasodilating effects
evaluated by digital pulse plethysmography.
Methods:
Twenty patients with stable angina pectoris were exercise tested before, after 2 and after 24 h of open nitrate patch treatment.
Results:
The effects observed after 2 h of treatment on exercise duration, ST-segment depression, blood pressure and heart rate were
lost in most individuals after 24 h. In contrast, the effects on the arterial pulse curves persisted after 24 h, with a mean
change from baseline of 29%, compared to 33% at 2 h. After 24 h, a significant decrease in haematocrit and an increase in
body weight were observed. The haematocrit changes correlated with the loss of clinical efficacy (r =0.57 for ST-segment depression, and r =0.54 for exercise duration).
Conclusion:
Clinical nitrate tolerance may be observed despite maintenance of the arterial vasodilating effects, and tolerance is more
related to plasma volume expansion as a counterregulatory mechanism.
Received: 28 February 1996/Accepted in revised form: 5 July 1996 相似文献
53.
A 62-year-old woman with diabetic triopathy developed widespread erythematous macules, numerous pustules, and a high fever after she underwent electric coagulation for vitreous hemorrhage. She was administered several drugs at that time. After discontinuation of the drugs, the eruption disappeared, and the fever returned to normal within two weeks. A positive patch test with isepamicin sulfate highly suggested that the symptoms described above were due to drug allergy. Cadralazine, which was positive in the drug lymphocyte stimulation test (DLST), could not be excluded from the causative drugs. A false-positive DLST with ofloxacin was confirmed by an accidental challenge test. To our knowledge, this is the first report of acute generalized exanthematous pustulosis due to isepamicin sulfate and/or cadralazine. 相似文献
54.
Auditory and vestibular system findings in patients with vertebrobasilar dolichoectasia 总被引:5,自引:0,他引:5
Impairment of the auditory-vestibular system has been reported in patients with vertebrobasilar dolichoectasia (VBD), but little is known about the underlying cause of the symptoms. Auditory testing (pure tone audiometry, auditory brain stem response and stapedius reflex) and vestibular tests (assessment of nystagmus, eye tracking tests, caloric test and rotational test) were performed in 23 patients with auditory-vestibular symptoms and/or cranial nerve impairment associated with VBD. Specific evidence of auditory and/or vestibular system impairment was observed in 19 cases (83%). Among patients with abnormal test findings, 47% had evidence suggesting peripheral impairment, 16% evidence suggesting central dysfunction, and 37% evidence suggesting both peripheral and central dysfunction. Although compression of the vestibulocochlear nerve plays an important role in the genesis of the auditory-vestibular dysfunction in patients with VBD, mechanism such as brain stem-cerebellar ischemia and impaired blood supply to the vestibular labyrinth may be just as important. 相似文献
55.
56.
Abstract: The small-dose (20 mg) oral iron absorption test (OIAT) was performed in 76 hospitalized elderly patients and 30 healthy adults. Of the elderly patients, 34 were considered as iron deficient (serum ferritin level <20 μg/L) of whom 23 were anaemic and 11 not anaemic, 21 had the anaemia of chronic disorders (ACD) and another 21 were non-anaemic patients with a normal serum ferritin level. There was a significant inverse correlation between the serum ferritin level as a measure of iron store and the maximum increase in serum iron during a 3-h test (Cmax), in the elderly as well as in the healthy adult group. A decision limit of 80 μg/dL for Cmax is a good discriminant between absent (serum ferritin <20 μg/L) and adequate body iron stores. Sixty-eight per cent of the patients with a serum ferritin level <20 μg/L but virtually none of the ACD patients, non-anaemic elderly inpatients with normal serum ferritin levels and healthy adults had a Cmax level >80 μg/L. Although further investigation is needed before the OIAT can be recommended as a valuable test for evaluating iron absorption, predicting mild iron deficiency and differentiating between different categories of anaemia, it seems worthwile that more effort should be done to validate this simple and safe test. 相似文献
57.
选择南方热区某特种部队战士52人,分两组分别口服5mgVitB1和VitB2,收集4h尿液,用荧光法进行负荷试验。结果:VitB1组,所测29人中,15人缺乏,9人不足,2人正常,3人充裕;VitB2组,所测23人中,11人缺乏,12人不足,反映该部队全年约5%的发病是由于VitB1、VitB2缺乏不足所致。其原因为膳食摄入不够 相似文献
58.
Active behaviors in the rat forced swimming test differentially produced by serotonergic and noradrenergic antidepressants 总被引:16,自引:0,他引:16
This study demonstrated that distinct patterns of active behaviors are produced by antidepressants that selectively inhibit norepinephrine (NE) or serotonin (5-HT) uptake in the rat forced swimming test (FST). A behavior sampling technique was developed to score the active behaviors swimming, climbing and diving, as well as immobility. The rat's behavior was recorded at the end of each 5-s period during the test session. The sampling technique was both reliable, as demonstrated by test-retest reliability and inter-rater reliability, and valid, as shown by comparison to the timing of behavior durations. Five different antidepressant drugs which block monoamine uptake and two 5-HT1A receptor agonists were shown to decrease immobility in the FST; however, they produced distinct patterns of active behaviors. The selective NE uptake inhibitors desipramine and maprotiline selectively increased climbing, whereas the selective serotonin reuptake inhibitors (SSRIs) fluoxetine, sertraline and paroxetine selectively increased swimming. The 5-HT1A receptor agonists 8-OH-DPAT and gepirone also selectively increased swimming. These results show that:1) SSRIs are not false negatives in the FST; 2) at least two behaviorally distinct processes occur in the FST; and 3) enhancement of NE neurotransmission may mediate climbing in the FST, whereas enhancement of 5-HT neurotransmission may mediate swimming. 相似文献
59.
Background: As in many parts of the world, the Schirmer tear test is the main test used by optometrists in Saudi Arabia for assessing adequacy of tear production. Variability of the test has been reported in different ethnic groups but not in Arabs. This paper looks at the mean and repeatability of the values obtained by the Schirmer test in a normal Arab population Method: The test was performed on the right eyes of 23 young adult Saudi male subjects at five visits over two weeks. Result: Results showed that for each subject the test values were not repeatable, varying widely over the period of evaluation. The mean value was estimated at 10.6 mm and the 95 per cent confidence limits were 7.9 and 13.3 mm. It was also established that the greater the amount of tears, the greater the variability. Conclusion: This study supports the claim that the Schirmer test is not repeatable and hence is unreliable. Therefore, caution should be exercised in employing it for clinical diagnosis. (Clin Exp Optom 1995; 78: 5: 190–193) 相似文献
60.
正常人口腔粘膜不同部位表面感觉的测试 总被引:1,自引:0,他引:1
目的 建立正常人口腔粘膜不同部位表面感觉的正常参考值,并测试各年龄组感觉值是否存在差异。方法 利用动静两点辨别觉试验,测试90例健康人口腔粘膜不同部位的表面感觉。结果 舌尖感觉功能最好,其次为舌背、舌腹、颊粘膜、口底和硬腭。健康人的口腔粘膜不同部位的表面感觉随着年龄增长有显著性变化。结论 口腔粘膜不同部位感觉辨别力存在差异,健康人口底、舌腹、舌背、颊和硬腭粘膜感觉功能有增龄性变化。 相似文献