全文获取类型
收费全文 | 18563篇 |
免费 | 1179篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 172篇 |
儿科学 | 482篇 |
妇产科学 | 383篇 |
基础医学 | 2117篇 |
口腔科学 | 322篇 |
临床医学 | 1523篇 |
内科学 | 3915篇 |
皮肤病学 | 225篇 |
神经病学 | 1023篇 |
特种医学 | 526篇 |
外科学 | 3299篇 |
综合类 | 639篇 |
一般理论 | 18篇 |
预防医学 | 1426篇 |
眼科学 | 506篇 |
药学 | 1836篇 |
中国医学 | 218篇 |
肿瘤学 | 1193篇 |
出版年
2023年 | 169篇 |
2022年 | 515篇 |
2021年 | 652篇 |
2020年 | 423篇 |
2019年 | 528篇 |
2018年 | 637篇 |
2017年 | 444篇 |
2016年 | 360篇 |
2015年 | 499篇 |
2014年 | 690篇 |
2013年 | 863篇 |
2012年 | 1287篇 |
2011年 | 1266篇 |
2010年 | 735篇 |
2009年 | 560篇 |
2008年 | 995篇 |
2007年 | 984篇 |
2006年 | 915篇 |
2005年 | 840篇 |
2004年 | 771篇 |
2003年 | 691篇 |
2002年 | 580篇 |
2001年 | 545篇 |
2000年 | 488篇 |
1999年 | 389篇 |
1998年 | 143篇 |
1997年 | 113篇 |
1996年 | 107篇 |
1995年 | 115篇 |
1994年 | 60篇 |
1993年 | 75篇 |
1992年 | 202篇 |
1991年 | 186篇 |
1990年 | 165篇 |
1989年 | 170篇 |
1988年 | 134篇 |
1987年 | 152篇 |
1986年 | 123篇 |
1985年 | 134篇 |
1984年 | 110篇 |
1983年 | 86篇 |
1982年 | 59篇 |
1981年 | 60篇 |
1979年 | 97篇 |
1978年 | 64篇 |
1977年 | 66篇 |
1975年 | 60篇 |
1974年 | 51篇 |
1973年 | 54篇 |
1972年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
Comparison of hamycin with trichomycin 总被引:2,自引:0,他引:2
982.
983.
984.
985.
Hearing impairment has been associated with cognitive deficits. It is not yet clear whether cochlear implants enable children to reduce or overcome these deficits. This study examined whether hearing impaired children with cochlear implants differed from hearing impaired children without cochlear implants or from hearing children. The three age-matched groups were compared on a non-verbal measure of cognition, the Leiter International Performance Scale-Revised (LIPS-R), and a measure of behaviour, the Child Behaviour Checklist (CBCL). Apart from their scores on the Attention Sustained Subtest of the LIPS-R, the performance of the implanted group and the hearing group closely corresponded, while the hearing impaired children without cochlear implants performed below the level achieved by both these groups. There were no differences between any groups on the CBCL. It was concluded that hearing impaired children with cochlear implants were able to perform at the same non-verbal cognitive level as hearing children. 相似文献
986.
Hichami A Morin C Rousseau E Khan NA 《American journal of respiratory cell and molecular biology》2005,33(4):378-386
We synthesized and assessed the role of a diacylglycerol (DAG)-containing docosahexaenoic acid (DHA), that is, 1-stearoyl-2-docosahexaenoyl-sn-glycerol (SDHG), in the contraction of guinea pig airway smooth muscle (ASM). We compared its action with 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) and 1,2-dioctanoyl-sn-glycerol (1,2-DiC8), a stable DAG analog. The three DAGs (SAG, SDHG, and 1,2-DiC8) induced reversible concentration-dependent contraction of ASM. SDHG induced higher guinea pig ASM contraction than did SAG and 1,2-DiC8. The effects of SDHG were blocked, to different extents, by nifedipine (L-type Ca2+ channel blocker). By employing GF-109203X (protein kinase C [PKC] inhibitor) and lanthanum (La3+), a nonselective cation channel blocker, we observed that SDHG evoked ASM contractile response via PKC-dependent and PKC-independent (but Ca2+-dependent) pathways. Interestingly, SAG exerted its action only by increasing [Ca2+]i and did not require PKC activation. To probe the implication of calcium mobilization, we employed thapsigargin (TG), which also induced ASM contraction in a calcium-dependent manner. SDHG and 1,2-DiC8, in a PKC-dependent manner, induced the phosphorylation of CPI-17 (myosin light chain phosphatase inhibitor of 17 kD). Furthermore, SAG and TG failed to phosphorylate CPI-17 in ASM cells. Our results suggest that different DAG species, produced during a dietary supplementation with fatty acids, could modulate the reactivity of airway smooth muscles in a PKC-dependent and -independent manner, and hence, may play a critical role in health and disease. 相似文献
987.
Levy PY Khan M Raoult D 《The New England journal of medicine》2005,352(11):1154-5; author reply 1154-5
988.
There is a close inter-relationship between oxidative stress, coagulation, inflammation, and smooth muscle cell growth as key components of atherosclerosis (Fig. 1). As an analgesic and anti-pyretic, aspirin has been in use for over a century. It acetylates the COX enzyme, irreversibly inhibiting the formation of prostaglandin. Its action on platelet TxA2 has highlighted its role as an anti-thrombotic agent in cardiovascular patients. Over the last two decades, unique anti-inflammatory properties of aspirin not shared by other non-steroidals have been discovered. Aspirin biotransforms into salicylate, which has diverse but potent anti-inflammatory properties. As we strive to better understand the concepts of atherogenesis, chronic inflammation, oxidative stress, and endothelial activation, these novel effects of aspirin provide new insights as to how this wonder drug works. These effects of aspirin alter many, if not all, components of the atherogenesis cascade shown in Fig. 1. 相似文献
989.
Dean N Lari H Saqqur M Amir N Khan K Mouradian M Salam A Romanchuk H Shuaib A 《The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques》2005,32(3):327-331
INTRODUCTION: Doppler ultrasound (DUS) is used as a screening tool to assess internal carotid artery (ICA) disease. Recent reports suggest that the DUS may be inaccurate in over 28% of patients. We sought to evaluate the accuracy of DUS, when performed in a dedicated stroke prevention clinic (SPC). METHODS: We retrospectively reviewed the charts of patients who had a DUS performed in our SPC, followed by conventional cerebral angiography. Three groups of patients were defined. Group 1 had DUS measured ICA stenosis of >50%; Group II had a DUS measured ICA stenosis of <50%; Group III had complete ICA occlusion on DUS. RESULTS: Sixty-seven patients (69 arteries) were included in the study. There were 45 patients in Group I and based on the findings of cerebral angiography, carotid endarterectomy was considered inappropriate in only one patient--a misclassification rate of 2.2% (95% CI: 0 - 6.5%). Group II consisted of 19 patients and on cerebral angiography, none of these patients had a stenosis of >50%--a misclassification rate of 0%. Group III consisted of five patients in whom DUS showed complete ICA occlusion. The angiogram confirmed the occlusion in all five patients--a misclassification rate of 0%. Overall, misclassification rate was 1.45% (95% CI: 0 - 4.3%). CONCLUSIONS: Doppler ultrasound when performed in a stroke prevention clinic (SPC), has a high accuracy in measuring ICA stenosis of >50%. Doppler ultrasound is reliable in detecting complete ICA occlusion and finally DUS is a reliable screening tool to rule out clinically significant ICA stenosis. 相似文献
990.
PURPOSE: To estimate the incidence and long-term outcome of brain tumor related seizures in children and to identify risk factors for adverse seizure outcome. METHODS: Analysis of medical records of children treated for brain tumor and seizures in a single institution. Children were identified from hospital database and neurology clinic records. Seizure status was characterized for the 6 months prior to most recent follow-up. RESULTS: Median follow-up after first seizure of the 157 analyzed children was 3.3 years. Tumor location was supratentorial in 81% and posterior fossa in 19%. Initial anti-epileptic drugs were phenytoin (n=52), carbamazepine (n=38), phenobarbital (n=14), gabapentin (n=31), or others (n=22). Seizures were controlled in 65% of the children and uncontrolled in 35% (17% intractable). Gabapentin showed a trend toward better seizure control (p=0.06). Neurologic deficit, T2 peri-cavity hyperintensity, and EEG slow waves were independently predictive of uncontrolled seizures by multivariate analysis. CONCLUSIONS: T2 peri-cavity hyperintensity, focal neurologic deficits, and EEG slow waves predict poor seizure control in children with brain tumors. Seizures can be controlled in most patients with brain tumors. Gabapentin use as first anti-epileptic drug needs to be studied prospectively. 相似文献