全文获取类型
收费全文 | 284738篇 |
免费 | 14760篇 |
国内免费 | 587篇 |
专业分类
耳鼻咽喉 | 3532篇 |
儿科学 | 9440篇 |
妇产科学 | 6145篇 |
基础医学 | 40409篇 |
口腔科学 | 6751篇 |
临床医学 | 25384篇 |
内科学 | 61273篇 |
皮肤病学 | 7261篇 |
神经病学 | 25947篇 |
特种医学 | 8302篇 |
外国民族医学 | 104篇 |
外科学 | 33683篇 |
综合类 | 1659篇 |
一般理论 | 129篇 |
预防医学 | 27344篇 |
眼科学 | 5347篇 |
药学 | 19239篇 |
6篇 | |
中国医学 | 847篇 |
肿瘤学 | 17283篇 |
出版年
2023年 | 1685篇 |
2022年 | 1617篇 |
2021年 | 4968篇 |
2020年 | 3157篇 |
2019年 | 5423篇 |
2018年 | 8978篇 |
2017年 | 6133篇 |
2016年 | 6237篇 |
2015年 | 6901篇 |
2014年 | 7709篇 |
2013年 | 11951篇 |
2012年 | 19636篇 |
2011年 | 19717篇 |
2010年 | 10167篇 |
2009年 | 7930篇 |
2008年 | 16720篇 |
2007年 | 17833篇 |
2006年 | 16631篇 |
2005年 | 16340篇 |
2004年 | 15436篇 |
2003年 | 14123篇 |
2002年 | 13173篇 |
2001年 | 6685篇 |
2000年 | 6627篇 |
1999年 | 5988篇 |
1998年 | 1512篇 |
1997年 | 1209篇 |
1996年 | 1107篇 |
1995年 | 1022篇 |
1994年 | 868篇 |
1992年 | 3468篇 |
1991年 | 3107篇 |
1990年 | 2950篇 |
1989年 | 2670篇 |
1988年 | 2562篇 |
1987年 | 2331篇 |
1986年 | 2231篇 |
1985年 | 2012篇 |
1984年 | 1543篇 |
1983年 | 1322篇 |
1979年 | 1310篇 |
1978年 | 953篇 |
1977年 | 872篇 |
1975年 | 864篇 |
1974年 | 1055篇 |
1973年 | 1073篇 |
1972年 | 996篇 |
1971年 | 990篇 |
1970年 | 910篇 |
1969年 | 944篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
Stéphane Thobois Jing Xie Helena Mollion Isabelle Benatru Emmanuel Broussolle 《Movement disorders》2004,19(8):965-966
We describe the first case of orofacial abnormal movements induced by adrafinil, a vigilance promoting agent of the same pharmacological class as modafinil. The dyskinesias did not spontaneously recover despite adrafinil withdrawal for a 4-month period. They were secondly dramatically improved by tetrabenazine, a presynaptic dopaminergic depleting drug which was introduced after the 4-month adrafinil-free period. 相似文献
982.
983.
Laurent Garel Josée Dubois Fran?oise Rypens Alain Ouimet Salam Yazbeck 《Journal l'Association canadienne des radiologistes》2004,55(1):39-44
OBJECTIVE: To report on the high incidence of anatomical variants of the origin and course of the internal spermatic vein (ISV) discovered at the time of percutaneous embolization of left varicoceles in a pediatric population. METHODS: We reviewed retrospectively the 65 cases of left varicocele treated by percutaneous embolization (grade II and III) in our institution between 1990 and 2000. The course of the left renal vein (LRV), the origin of the ISV, and the number of ISVs and their pathway were recorded in all cases, according to the B?hren classification. RESULTS: In 37/65 (57%), the ISV was single and arose from a normal LRV (type I). The following variants were encountered: type V--circumaortic LRV 9/65 (14%); type IVb--intrarenal origin of ISV 8/65 (12%); type II--multiple ISV 5/65 (8%); and pelvic collaterals 6/65 (9%). CONCLUSION: Venous anatomical variants are frequently encountered (43%) at the time of left varicocele embolization in children. Such variants often impose some adjustments to the technique of embolization and, at times, hamper the procedure. 相似文献
984.
BACKGROUND: Photon energy recovery (PER) is a spectral deconvolution technique validated for scatter removal in patients and phantom studies. The purpose of this study was to examine the impact of PER on left ventricular volume measurement based on myocardial perfusion single photon emission computed tomography (SPECT). METHODS AND RESULTS: SPECT acquisitions were performed by use of a static cardiac phantom and in 25 patients after a rest injection of technetium 99m sestamibi by use of multiple energy windows (126-136, 137-144, and 145-154 keV). Data were successively reconstructed with and without PER, by use of iterative reconstruction and post-processing filtering (Butterworth filter; order, 5; cutoff, 0.30 cycles/pixel). Image contrast was evaluated in reconstructed data, and volumes were calculated by use of QGS. PER increased reconstructed image contrast from 62% +/- 2.7% to 84.3% +/- 5.7% in the phantom studies (P <.0001) and from 49% +/- 2% to 73% +/- 2% in patients (P <.0001). Although it remained underestimated (P <.0001), phantom volume was higher after PER correction compared with uncorrected data (50.9 +/- 0.8 mL vs 44.6 +/- 1 mL, P <.0001). The error in volume measurement was decreased by PER correction (16.6% +/- 1.3% vs 27% +/- 1.7% [uncorrected data], P <.0001). In patients, left ventricular volume increased from 83 +/- 10 mL to 91 +/- 10 mL (P <.0001), and the PER-induced volume increase was correlated with the image contrast increase (r = 0.61, P =.001). Finally, the percentage of volume increase was higher in patients with small left ventricular volumes. CONCLUSIONS: PER has a significant impact on image contrast and left ventricular volume measurement by use of perfusion SPECT. PER improves the accuracy of phantom volume assessment. In patients, volume increase is correlated to image contrast increase and is higher in those with small ventricles. 相似文献
985.
Michael C Graves Milan Fiala Lu Anne V Dinglasan Nancy Q Liu James Sayre Francesco Chiappelli Cees van Kooten Harry V Vinters 《Amyotrophic lateral sclerosis and other motor neuron disorders》2004,5(4):213-219
Recent studies have shown inflammatory markers in affected neural tissues of amyotrophic lateral sclerosis (ALS) patients. We examined immunocytochemically spinal cord tissues of six patients with ALS, two with corticospinal tract degeneration secondary to cerebral infarcts and three control subjects without neuropathologic abnormalities. ALS spinal cords had dense macrophage infiltration (one log greater than control spinal cords) involving the white and gray matter, with heaviest infiltration of lateral and ventral columns and, in one patient, prefrontal gyrus and the occipital lobes of the brain. Macrophages in ALS spinal cord showed strong expression of cyclooxygenase-2 (COX-2) (one log greater than control tissues) and inducible nitric oxide synthase. In the gray matter, macrophages surrounded and appeared to phagocytize neurons (NeuN-positive) that appeared to be dying. Vessels showed damage to the tight junction protein ZO-1 in relation to perivascular CD40 receptor-positive macrophages and CD40 ligand-positive T lymphocytes. ALS spinal cords, but not control cords, were sparsely infiltrated with mast cells. In control cases with corticospinal tract degeneration following hemispheric cerebral infarction, macrophage infiltration of the white matter was COX-2-negative and restricted to lateral and anterior corticospinal tracts. Our data suggest that inflammation in ALS spinal cord and cortex is based on innate immune responses by macrophages and mast cells and adaptive immune responses by T cells. 相似文献
986.
987.
George M Brinson Douglas A Chen Moisés A Arriaga 《Otolaryngology--head and neck surgery》2007,136(3):415-421
OBJECTIVE: This study compares the efficacy of endolymphatic mastoid shunt (EMS) versus endolymphatic sac decompression (ESD) without sac incision for the treatment of Ménière's disease. STUDY DESIGN AND SETTING: The AAO-HNS Guidelines for the Diagnosis and Evaluation of Therapy in Ménière's disease were used to retrospectively identify suitable candidates for the study. All patients who failed medical management and underwent either endolymphatic-mastoid shunt (EMS) (n = 88) or endolymphatic sac decompression (ESD) (n = 108) were selected for review using the AAO-HNS guidelines. The study was carried out at a tertiary care neurotology private practice. RESULTS: EMS and ESD were equally effective in reducing the incidence and severity of vertigo attacks with significant improvement in 67 percent and 66 percent of patients, respectively. CONCLUSION: Both EMS and ESD are effective, nondestructive alternatives for patients who have failed medical management of Ménière's disease with similar long-term hearing outcomes. SIGNIFICANCE: This is the only study within the same institution using AAO-HNS guidelines comparing EMS versus ESD. 相似文献
988.
Association of HLA-DQA1*03011-DQB1*0301 haplotype with the development of respiratory scleroma. 总被引:1,自引:0,他引:1
Luis Alberto Sánchez-Marín Daniel Bross-Soriano José Arrieta Simón Kawa-Karasik Víctor Martínez-Vilchis Rocío Jiménez-Lucio Angélica Olivo-Díaz 《Otolaryngology--head and neck surgery》2007,136(3):481-483
OBJECTIVE: Respiratory scleroma (RS) is a progressive, chronic, granulomatous disease caused by Klebsiella rhinoscleromatis. There is only one report of RS association with HLA-DQ3. In this study, molecular association of HLA class II and RS was determined. STUDY DESIGN AND SETTING: Nine RS patients and 163 healthy controls were compared. DQA1, DQB1, and DRB1 loci were typed. RESULTS: Statistical analysis demonstrated association between DQB1*0301 and susceptibility to RS (P(c) = 0.004). Haplotype analysis showed an association of DQA1*03011-DQB1*0301 (P = 1.21E-19) and DRB1*0407-DQA1*03011-DQB1*0301 (P = 0.0002). CONCLUSIONS: Results established that DQA1*03011-DQB1*0301 haplotype is a strong risk factor for development of RS. 相似文献
989.
Miguelina Hernández Héctor Scannone Héctor J Finol Maria E Pineda Irma Fernández Alba M Vargas María E Girón Irma Aguilar Alexis Rodríguez-Acosta 《Experimental and toxicologic pathology》2007,59(2):129-137
This study explored the toxic effects of crotoxin isolated from Crotalus durissus cumanensis venom on the ultrastructure of mice cardiac autonomic nervous system. Mice were intravenously injected with saline (control group) and crotoxin diluted in saline venom (study group) at a dose of 0.107 mg/kg mouse body weight. Samples from the inter-ventricular septum were prepared for electron microscopy after 6 h (G1), 12 h (G2), 24 h (G3) and 48 h (G4). The G1 group showed some cardiomyocyte with pleomorphic mitochondria. Capillary swollen walls, nerve cholinergic endings with depleted acetylcholine vesicles in their interior and other depletions were observed. A space completely lacking in contractile elements was noticed. The G2 group demonstrated a myelinic figure, a subsarcolemic region with few myofibrils and nervous cholinergic terminal with scarce vacuoles in their interior. The G3 group demonstrated a structure with a depleted axonic terminal, mitochondrias varying in size and enhanced electron density. In addition, muscular fibers with myofibrillar structure disorganization, a depleted nervous structure surrounded by a Schwann cell along with an abundance of natriuretic peptides, were seen. An amyelinic terminal with depleted Schwann cell and with scarce vesicles was also observed. Finally, axonic lysis with autophagic vacuoles in their interior and condensed mitochondria was observed in the G4 group. This work describes the first report of ultrastructural damage caused by crotoxin on mice cardiac autonomic nervous system. 相似文献
990.
G Diéguez A L García M V Conde B Gómez L Santamaría S Lluch 《Microvascular research》1987,33(2):143-154
The carotid rete of Artiodactyla, an intracranial arterial plexus which supplies blood to the brain, has intrigued investigators for a long time. This study was designed to examine the responsiveness of isolated retial arteries (250-700 microns in external diameter) of goat, pig, and cattle. The findings in these arteries were compared to those observed in cerebral arteries (250-650 microns in external diameter) of the same animal species. The magnitude of the arterial responses to potassium chloride varied with the resting tension applied to the tissue. The two types of vessels exhibited similar resting tension values (0.3 g) for maximal tension development in response to potassium chloride; however, the ability of retial vessels to contract in the presence of potassium chloride was consistently smaller than that of cerebral arteries. The contractile response of retial arteries to norepinephrine (10(-9) to 10(-4) M), tyramine (10(-8) to 10(-3) M), and field electrical stimulation (2-16 Hz) was negligible. The same retial arteries exhibited dose-dependent contractions in response to 5-hydroxytryptamine (10(-9) to 10(-5) M) and histamine (10(-9) to 3 X 10(-4) M). Cerebral arteries exhibited larger responses to the vasoactive agents than retial arteries. Our findings indicate that retial arteries have a small vasomotor activity in response to adrenergic stimulation or to vasoactive agents. Therefore, the carotid rete of Artiodactyla may have a low ability to change resistance to blood flow under neural or hormonal influences. 相似文献