全文获取类型
收费全文 | 8409篇 |
免费 | 468篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 111篇 |
儿科学 | 345篇 |
妇产科学 | 344篇 |
基础医学 | 1089篇 |
口腔科学 | 195篇 |
临床医学 | 629篇 |
内科学 | 1950篇 |
皮肤病学 | 139篇 |
神经病学 | 669篇 |
特种医学 | 369篇 |
外科学 | 1216篇 |
综合类 | 93篇 |
预防医学 | 581篇 |
眼科学 | 161篇 |
药学 | 531篇 |
中国医学 | 58篇 |
肿瘤学 | 415篇 |
出版年
2022年 | 53篇 |
2021年 | 99篇 |
2020年 | 74篇 |
2019年 | 119篇 |
2018年 | 143篇 |
2017年 | 101篇 |
2016年 | 100篇 |
2015年 | 149篇 |
2014年 | 216篇 |
2013年 | 278篇 |
2012年 | 377篇 |
2011年 | 396篇 |
2010年 | 233篇 |
2009年 | 200篇 |
2008年 | 439篇 |
2007年 | 511篇 |
2006年 | 474篇 |
2005年 | 452篇 |
2004年 | 437篇 |
2003年 | 385篇 |
2002年 | 418篇 |
2001年 | 342篇 |
2000年 | 369篇 |
1999年 | 294篇 |
1998年 | 142篇 |
1997年 | 114篇 |
1996年 | 108篇 |
1995年 | 88篇 |
1994年 | 81篇 |
1993年 | 83篇 |
1992年 | 176篇 |
1991年 | 158篇 |
1990年 | 127篇 |
1989年 | 115篇 |
1988年 | 124篇 |
1987年 | 125篇 |
1986年 | 83篇 |
1985年 | 88篇 |
1984年 | 55篇 |
1983年 | 48篇 |
1982年 | 35篇 |
1981年 | 37篇 |
1980年 | 24篇 |
1979年 | 31篇 |
1978年 | 24篇 |
1977年 | 22篇 |
1976年 | 24篇 |
1973年 | 24篇 |
1970年 | 31篇 |
1968年 | 35篇 |
排序方式: 共有8895条查询结果,搜索用时 0 毫秒
1.
2.
3.
José Luis R Martin Víctor Pérez Montse Sacristán Fernando Rodríguez-Artalejo Cristóbal Martínez Enric Alvarez 《European psychiatry》2006,21(1):11-20
OBJECTIVE: To assess antipsychotic medication in the treatment of schizophrenia, based on trial drop-out rates. METHOD: The studies included were randomised controlled trials that compared any of the four clinically best-established atypical antipsychotics (quetiapine, olanzapine, risperidone or clozapine) against either of two typical antipsychotics regarded as the gold standard (haloperidol or chlorpromazine). RESULTS: Meta-analysis indicated less risk of all-cause patient withdrawal from atypical medication trials where dosage was flexible, in both the short, relative risk (RR) 0.70 (95% CI 0.64-0.76), P<0.00001, and long term, RR 0.72 (0.65-0.80), P<0.00001. Similar results were observed for withdrawal due to adverse events, RR: 0.54 (0.41-0.72), P<0.0001. Nevertheless, the favourable effects of atypical medication disappeared in trials relying on fixed dosage. CONCLUSIONS: We detected a significant positive effect in terms of the outcome of treatment discontinuation for atypical versus typical medication, though only where the use of flexible rather than fixed doses (closer to an experimental control situation) was possible. 相似文献
4.
Computed tomographic (CT) scans of the brain in a child with Smith-Lemli-Opitz syndrome revealed enlargement of the ventricular system, hypoplasia of the cerebellum, and abnormal thickening of the gray matter, consistent with pachygyria. These findings have been previously noted in autopsies performed on patients with this disorder. We conclude that CT scanning is a valuable tool in the evaluation of children suspected of having the Smith-Lemli-Opitz syndrome. 相似文献
5.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
6.
7.
Localization of epileptogenic foci using a simple reference-subtraction montage to document small interchannel time differences 总被引:1,自引:0,他引:1
P Jayakar M S Duchowny T J Resnick L A Alvarez 《Journal of clinical neurophysiology》1991,8(2):212-215
We present a modified EEG montage that detects small interchannel time differences and assists in localizing the epileptogenic focus. Regions with apparently synchronous epileptic discharges are displayed simultaneously in referential and subtraction derivations. The subtraction derivation is a bipolar configuration of two regions of interest that are not necessarily adjacent. The referential derivation reveals the polarity, voltage, and morphology of the two discharges, and the subtraction derivation detects asynchrony; the combined reference-subtraction derivation thus indicates the region that is activated first. 相似文献
8.
Ignacio Alvarez Alvarez M.D. Pedro Sanchez Lazo Ph.D. Sofia Ramos Gonzalez Ph.D. J. Pablo Rodrigo Tapia M.D. Faustino Nunez Batalla M.D. Carlos Suarez Nieto M.D. 《American journal of otolaryngology》1997,18(6):375
Purpose: Increasingly, evidence has shown that human papillomavirus (HPV) plays a role in the induction of certain carcinomas. The presence of HPV sequences in 56 previously untreated oral and pharyngolaryngeal carcinomas was examined by the polymerase chain reaction (PCR).Materials and Methods: After DNA extraction, samples underwent 40 replication cycles with specific oligonucleotide primers corresponding to sequences from the E6 open-reading frame of HPV-6b, HPV-16, and HPV-18. To determine the E6 genomic integration, positive samples were processed with specific primers for the corresponding HPV L1 genes. Genomic HPV DNA cloned into PBR 322 was used as positive control.Results: HPV E6 DNA of the 6b and 16 types was detected in 14 patients (25%). The L1 gene was not present.Conclusion: Detected HPV E6 DNA might be integrated into the cell genome in the positive cases as indicated by the absence of the L1 gene-coding for the viral capside. Histological and clinical parameters, such as tumor location, degree of differentiation, stage, recurrence, and survival rates, were unrelated to the presence of HPV. 相似文献
9.
Jehad Al Watban Georges Rodesch Hortensia Alvarez Pierre Lasjaunias 《Child's nervous system》1995,11(7):406-408
The authors present three cases of vein of Galen aneurysmal malformations (VGAMs) diagnosed in infancy and submitted by the referring teams for stereotactic radiosurgery as the initial therapy (therapeutic doses ranging between 20–25 Gy and 40–50 Gy to the peak dose). After the conventional follow-up of 18–24 months, no change could be detected in the angioarchitecture of the lesions. All three cases were then referred for endovascular treatment and underwent embolization by the transarterial route using liquid adhesives (N-butyl cyanoacrylate). This resulted in complete anatomical exclusion of the lesion. Regardless of the theoretical efficiency of radiosurgery in the management of brain arteriovenous malformations, the present authors believe that transarterial embolization remains the treatment of choice in VGAMs. It offers a high rate of morphological cure and the best chances for normal neurocognitive development. The time required by radiosurgery to achieve a significant result is too long for developing and maturing brain and may not prevent the negative effects of the lesion, mainly in regard to hemo- and hydrodynamic disorders (atrophy, subcortical calcifications, etc.) created by the VGAM, thus leading to irreversible mental retardation. 相似文献
10.
Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials 总被引:1,自引:0,他引:1
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed
and treated with antibiotics. OBJECTIVE: This study aimed to determine the
evidence for the effectiveness of antibiotic treatment in acute maxillary
sinusitis in adults by assessing the methodological quality of
placebo-controlled double-blind randomized trials. METHOD: An evaluation by
four raters through a 35-item scoring-scale for internal and external
validity of all placebo-controlled double-blind randomized trials on acute
sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five
trials were excluded because they were not placebo-controlled,
double-blind, randomized, or were carried out in patients with chronic
sinusitis or in children. The three remaining trials were performed in
different populations (one in general practice) between 1973 and 1978. Only
one study claimed superiority of antibiotic treatment. Different inclusion
criteria and major outcome measures were used by the authors. The
reliability of major outcome events was reported poorly or not at all and
in two studies outcome measures were clinically inappropriate. The studies
scored 30-62% of the maximum attainable score for internal validity and
10-20% for external validity. CONCLUSION: The effectiveness of antibiotic
treatment in acute maxillary sinusitis in a general practice population is
not based sufficiently on evidence.
相似文献