全文获取类型
收费全文 | 3458篇 |
免费 | 247篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 130篇 |
妇产科学 | 48篇 |
基础医学 | 411篇 |
口腔科学 | 36篇 |
临床医学 | 344篇 |
内科学 | 653篇 |
皮肤病学 | 91篇 |
神经病学 | 334篇 |
特种医学 | 234篇 |
外科学 | 375篇 |
综合类 | 244篇 |
一般理论 | 1篇 |
预防医学 | 346篇 |
眼科学 | 45篇 |
药学 | 162篇 |
中国医学 | 40篇 |
肿瘤学 | 150篇 |
出版年
2023年 | 23篇 |
2022年 | 39篇 |
2021年 | 83篇 |
2020年 | 53篇 |
2019年 | 57篇 |
2018年 | 77篇 |
2017年 | 52篇 |
2016年 | 62篇 |
2015年 | 69篇 |
2014年 | 111篇 |
2013年 | 146篇 |
2012年 | 159篇 |
2011年 | 167篇 |
2010年 | 164篇 |
2009年 | 133篇 |
2008年 | 149篇 |
2007年 | 129篇 |
2006年 | 149篇 |
2005年 | 129篇 |
2004年 | 113篇 |
2003年 | 124篇 |
2002年 | 106篇 |
2001年 | 97篇 |
2000年 | 74篇 |
1999年 | 77篇 |
1998年 | 69篇 |
1997年 | 87篇 |
1996年 | 69篇 |
1995年 | 57篇 |
1994年 | 50篇 |
1993年 | 45篇 |
1992年 | 58篇 |
1991年 | 40篇 |
1990年 | 63篇 |
1989年 | 58篇 |
1988年 | 49篇 |
1987年 | 59篇 |
1986年 | 54篇 |
1985年 | 57篇 |
1984年 | 40篇 |
1983年 | 18篇 |
1982年 | 28篇 |
1981年 | 20篇 |
1980年 | 21篇 |
1979年 | 25篇 |
1975年 | 17篇 |
1974年 | 17篇 |
1973年 | 19篇 |
1971年 | 18篇 |
1970年 | 15篇 |
排序方式: 共有3726条查询结果,搜索用时 78 毫秒
1.
2.
3.
P E Santos E Piontelli Y R Shea M L Galluzzo S M Holland M E Zelazko S D Rosenzweig 《Medical mycology》2006,44(8):749-753
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients. 相似文献
4.
PURPOSE: To examine longitudinal changes in mood and empathy over the course of the internal medicine residency. METHOD: The authors conducted a cohort study of 61 residents who completed the Profile of Mood States (POMS) and the Interpersonal Reactivity Index (IRI) at six time points during their internal medicine residency at a university-based program. (POMS was administered five times, and IRI was administered six times.) The main outcomes measured were trends in mood disturbances and multiple domains of empathy over the three-year residency, and comparisons to norms. RESULTS: Response rates varied from Time 1 to Time 6 (98%, 72%, 79%, 79%, 94%, and 95%, respectively). Interns had better scores on four POMS subscales: Depression-Dejection (p = .0031), Anger-Hostility (p < .0001), Fatigue-Inertia (p < .0001), and Vigor-Activity (p < .0001) compared with later administrations, especially midinternship. By the end of residency all POMS scores were returning towards baseline (effects sizes in the .20 s), but only depression was no longer significantly different. IRI scores showed the decline in Empathic Concern remained over residency whereas Personal Distress peaked midinternship year but approached baseline at the end of residency. Compared with the general population, the graduating residents were less tense, depressed, and confused. Personal Distress was significantly lower than the norm group. CONCLUSIONS: Internal medicine residency presents challenges resulting in common mood disturbances. Although graduating residents appear to be better off than the population norms, some domains of their mood disturbances and empathy never fully recover from their internship year. 相似文献
5.
Suppurative corneal ulceration in Bangladesh 总被引:8,自引:0,他引:8
AAS Dunlop MB BS ED Wright MRCPath † SA Howlader‡ I Nazrul‡ R Husain‡ K McClellan FRACO § FA Billson FRACO § 《Clinical & experimental ophthalmology》1994,22(2):105-110
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season. 相似文献
6.
7.
8.
Microtubule-associated protein tau is required for axonal neurite elaboration by neuroblastoma cells. 总被引:5,自引:0,他引:5
NB2a/d1 neuroblastoma cells constitutively express multiple isoforms of the microtubule-associated protein tau and incorporate this protein into the axonal neurites elaborated during serum deprivation. To examine whether or not tau played an essential role in axonal outgrowth, cells cultured in serum-free medium were treated at 24 h intervals with antisense- and sense-oriented cDNA oligonucleotides (25 or 36 mers that span or are upstream of tau initiation codon) and were simultaneously serum deprived. Oligonucleotide uptake was confirmed by determination of intracellular levels of radiolabeled oligonucleotides. Treatment for 48 h with tau antisense oligonucleotides reversibly inhibited the expression of tau and the number of neurite-bearing cells compared with treatment with sense oligonucleotides. By contrast, tubulin expression was not affected. When cells were treated with antisense oligonucleotide simultaneously with serum deprivation, the initial outgrowth of neurites was unaffected, but continued neurite elongation was prevented. By contrast, neurite outgrowth at 4 h was inhibited when cells were pretreated with tau antisense 24 h before serum deprivation. Furthermore, intracellular delivery of anti-tau antiserum prevented neurite outgrowth and, in cells that had previously been deprived of serum for 24 h, induced retraction of existing neurites. These findings indicate that both the initiation and the continued outgrowth of neurites are dependent on tau and that pre-existing cytoplasmic pools of tau can mediate initial neuritogenesis. 相似文献
9.
Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation 总被引:5,自引:0,他引:5
Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs. 相似文献
10.
The reproducibility of data from a Food Frequency Questionnaire among low-income Latina mothers and their children.
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We examined the 3-month and 1-year reproducibility of mothers' and children's dietary intakes of calories and 11 nutrients derived from oral administrations of a food frequency questionnaire to 166 Latina women. One-year correlations generally ranged from 0.40 to 0.55 for both mothers and children. For most nutrients, roughly half the children in the highest (lowest) quartile of intake at baseline were also in the highest (lowest) quartile 1 year later. The food frequency questionnaire has great potential for measuring typical nutrient intakes in these populations. 相似文献