全文获取类型
收费全文 | 51173篇 |
免费 | 3823篇 |
国内免费 | 1113篇 |
专业分类
耳鼻咽喉 | 538篇 |
儿科学 | 1021篇 |
妇产科学 | 903篇 |
基础医学 | 7296篇 |
口腔科学 | 2045篇 |
临床医学 | 4142篇 |
内科学 | 10751篇 |
皮肤病学 | 973篇 |
神经病学 | 4454篇 |
特种医学 | 1531篇 |
外国民族医学 | 2篇 |
外科学 | 7335篇 |
综合类 | 2595篇 |
一般理论 | 15篇 |
预防医学 | 3455篇 |
眼科学 | 1139篇 |
药学 | 4023篇 |
中国医学 | 480篇 |
肿瘤学 | 3411篇 |
出版年
2023年 | 227篇 |
2022年 | 472篇 |
2021年 | 1111篇 |
2020年 | 614篇 |
2019年 | 950篇 |
2018年 | 1356篇 |
2017年 | 972篇 |
2016年 | 973篇 |
2015年 | 1198篇 |
2014年 | 1642篇 |
2013年 | 2024篇 |
2012年 | 3051篇 |
2011年 | 3057篇 |
2010年 | 1799篇 |
2009年 | 1573篇 |
2008年 | 2644篇 |
2007年 | 2810篇 |
2006年 | 2505篇 |
2005年 | 2265篇 |
2004年 | 1988篇 |
2003年 | 1736篇 |
2002年 | 1599篇 |
2001年 | 2436篇 |
2000年 | 2292篇 |
1999年 | 1939篇 |
1998年 | 859篇 |
1997年 | 585篇 |
1996年 | 405篇 |
1995年 | 360篇 |
1994年 | 325篇 |
1993年 | 285篇 |
1992年 | 1075篇 |
1991年 | 945篇 |
1990年 | 847篇 |
1989年 | 929篇 |
1988年 | 845篇 |
1987年 | 775篇 |
1986年 | 729篇 |
1985年 | 641篇 |
1984年 | 423篇 |
1983年 | 355篇 |
1982年 | 224篇 |
1981年 | 174篇 |
1980年 | 138篇 |
1979年 | 219篇 |
1978年 | 110篇 |
1977年 | 107篇 |
1973年 | 111篇 |
1972年 | 105篇 |
1971年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
This paper is a summary of our observations on 105 cases of infantile spasms. The age of onset was around six months after birth, but the patients came for treatment mainly about one year after onset. Fever of unknown cause, asphyxia, birth injury, infection of the central nervous system, tuberous sclerosis, phenylketonuria and recent immunization etc. were complained. Clinically, it is characterized by head nodding, mental retardation, myoclonic jerks and various neurologic deficits. EEG findings showed classical or modified arrythmia or other epileptiform patterns. About one third of 22 cases examined had abnormal brain stem auditory evoked potentials. Among 42 patients who underwent CT scanning before ACTH treatment, 18 were normal and 7 abnormal; during ACTH treatment 3 normal and 4 abnormal; after completion of treatment, 4 normal and 6 abnormal, suggesting no further atrophy of the brain. Examination of trace elements of the hair by particle-induced X-ray emission (PIXE) method in 23 patients revealed a significant difference in lead, calcium and zinc contents between patients and 101 controls, but no statistical difference in iron and copper contents between the two groups. Sodium valproate, prednisone and ACTH appear to be effective in the treatment of infantile spasms. Eight patients fully recovered, and they can go to school without difficulty. Many patients derived various degrees of improvement to the satisfaction of their parents. Two patients were still amented and often attacked by myoclonus. The effects, side effects of these drugs, and the possible pathogenesis were discussed.
相似文献
52.
53.
Xiaoguang Zhu Raymond Q Migrino Robert S Hellman Tejas Brahmbhatt Ming Zhao 《Nuclear medicine communications》2008,29(9):764-769
OBJECTIVE: The C2A domain of Synaptotagmin I is a molecular probe for the specific imaging of cell death. Here we test the hypothesis that the uptake of 99mTc-C2A in the acute phase of an infarction is associated with cardiac dysfunction in follow-ups. METHODS: The left coronary artery was occluded in Sprague-Dawley rats for 0, 10, 20, and 30 min. 99mTc-C2A was injected intravenously at 2 h of reperfusion. Anterior planar images were acquired with one million counts on a gamma camera 3 h after injection. 99mTc-C2A uptake was calculated as the total counts in the left ventricle region minus blood pool signal. The in-vivo signal detected was correlated with wall motion score index at 1 and 3 weeks follow-ups measured by echocardiography. RESULTS: 99mTc-C2A uptake was higher with increased ischemic time (2244+/-852, 4054+/-1223, and 6178+/-1451 for 10, 20, and 30 min ischemia, analysis of variance P<0.001). A significant correlation was found between 99mTc-C2A uptake and wall motion score index at 1 week (R=0.800, P=0.0006) and 3 weeks (R=0.810, P=0.0008). CONCLUSION: In this ischemia/reperfusion model, 99mTc-C2A uptake in the acute phase was associated with functional abnormality at 1 and 3 weeks. This demonstrates the potential diagnostic and prognostic value of 99mTc-C2A as a novel imaging agent. 相似文献
54.
Luiz Fernando Tomazinho Mario J Avila-Campos 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,103(2):285-288
Black-pigmented anaerobic rods such as Prevotella spp. and Porphyromonas spp. are involved in the etiology and perpetuation of endodontic infections. The aim of this study was to evaluate the prevalence of these species in chronic endodontic infections by using culture and polymerase chain reaction (PCR) techniques. Samples of 100 patients with root canals displaying chronic endodontic infections were obtained by sterilized paper points. Bacterial identification was performed by using culture and PCR techniques. By culture, in 33% of the samples, P. intermedia-P. nigrescens (75.8%), P. gingivalis (27.3%), and P. endodontalis (9.1%) were identified, and by PCR 60% of the samples harbored P. nigrescens (43.3%), P. gingivalis (43.3%), P. intermedia (31.7%), and P. endodontalis (23.3%). The presence of these black-pigmented anaerobic rods alone or in association in chronic endodontic infections seems to be frequent. PCR is a very sensitive technique for detecting DNA from bacterial cells. Culturing is only able to reveal living bacteria and is less sensitive for the identification of low numbers of bacterial cells. 相似文献
55.
56.
57.
J Chhabra Y-Z Li H Alkhouri A E Blake Q Ge C L Armour J M Hughes 《The European respiratory journal》2007,29(5):861-870
Degranulating mast cells are increased in the airway smooth muscle (ASM) of asthmatics, where they may influence ASM function. The aim of the present study was to determine whether histamine and tryptase modulate ASM cell granulocyte-macrophage colony-stimulating factor (GM-CSF) and RANTES (regulated on activation, normal T-cell expressed and secreted) release and also to examine which receptors are involved in this release. Confluent, quiescent ASM cells from asthmatic and nonasthmatic donors were treated with histamine (1 microM-100 microM) with and without histamine receptor antagonist pre-treatment, or the protease-activated receptor (PAR)-2 agonists tryptase (0.5-5 nM) and SLIGKV (100 and 400 microM). The cells were then stimulated with interleukin (IL)-1beta and/or tumour necrosis factor (TNF)-alpha (10 ng.mL(-1)) or left unstimulated for 24 h. Release of GM-CSF and RANTES was determined by ELISA and prostaglandin (PG)E(2) measured by enzyme immunoassay. Neither histamine nor tryptase induced ASM GM-CSF or RANTES secretion. However, histamine increased IL-1beta-induced GM-CSF release and markedly reduced TNF-alpha-induced RANTES release by both asthmatic and nonasthmatic cells to a similar extent, but did not modulate PGE(2) release. All changes involved activation of the histamine H1 receptor as they were partially or fully blocked by chlorpheniramine, but not ranitidine. Tryptase, via its proteolytic activity, also potentiated GM-CSF, but not RANTES, release from asthmatic and nonasthmatic ASM cells induced by both cytokines. PAR-2 involvement in the tryptase potentiation was unlikely because SLIGKV had no effect. In conclusion, mast cells, through histamine and tryptase, may locally modulate airway smooth muscle-induced inflammation in asthma. 相似文献
58.
Postoperative nomogram predicting the 10-year probability of prostate cancer recurrence after radical prostatectomy. 总被引:3,自引:0,他引:3
Andrew J Stephenson Peter T Scardino James A Eastham Fernando J Bianco Zohar A Dotan Christopher J DiBlasio Alwyn Reuther Eric A Klein Michael W Kattan 《Journal of clinical oncology》2005,23(28):7005-7012
PURPOSE: A postoperative nomogram for prostate cancer recurrence after radical prostatectomy (RP) has been independently validated as accurate and discriminating. We have updated the nomogram by extending the predictions to 10 years after RP and have enabled the nomogram predictions to be adjusted for the disease-free interval that a patient has maintained after RP. METHODS: Cox regression analysis was used to model the clinical information for 1,881 patients who underwent RP for clinically-localized prostate cancer by two high-volume surgeons. The model was externally validated separately on two independent cohorts of 1,782 patients and 1,357 patients, respectively. Disease progression was defined as a rising prostate-specific antigen (PSA) level, clinical progression, radiotherapy more than 12 months postoperatively, or initiation of systemic therapy. RESULTS: The 10-year progression-free probability for the modeling set was 79% (95% CI, 75% to 82%). Significant variables in the multivariable model included PSA (P = .002), primary (P < .0001) and secondary Gleason grade (P = .0006), extracapsular extension (P < .0001), positive surgical margins (P = .028), seminal vesicle invasion (P < .0001), lymph node involvement (P = .030), treatment year (P = .008), and adjuvant radiotherapy (P = .046). The concordance index of the nomogram when applied to the independent validation sets was 0.81 and 0.79. CONCLUSION: We have developed and validated as a robust predictive model an enhanced postoperative nomogram for prostate cancer recurrence after RP. Unique to predictive models, the nomogram predictions can be adjusted for the disease-free interval that a patient has achieved after RP. 相似文献
59.
60.