全文获取类型
收费全文 | 51913篇 |
免费 | 2948篇 |
国内免费 | 161篇 |
专业分类
耳鼻咽喉 | 562篇 |
儿科学 | 1615篇 |
妇产科学 | 1396篇 |
基础医学 | 7357篇 |
口腔科学 | 1608篇 |
临床医学 | 5267篇 |
内科学 | 10860篇 |
皮肤病学 | 1057篇 |
神经病学 | 4980篇 |
特种医学 | 1567篇 |
外科学 | 6170篇 |
综合类 | 277篇 |
现状与发展 | 1篇 |
一般理论 | 20篇 |
预防医学 | 4522篇 |
眼科学 | 900篇 |
药学 | 3744篇 |
中国医学 | 197篇 |
肿瘤学 | 2922篇 |
出版年
2023年 | 477篇 |
2022年 | 602篇 |
2021年 | 1339篇 |
2020年 | 815篇 |
2019年 | 1244篇 |
2018年 | 1767篇 |
2017年 | 1296篇 |
2016年 | 1391篇 |
2015年 | 1520篇 |
2014年 | 1817篇 |
2013年 | 2642篇 |
2012年 | 3964篇 |
2011年 | 4047篇 |
2010年 | 1999篇 |
2009年 | 1685篇 |
2008年 | 3151篇 |
2007年 | 3268篇 |
2006年 | 3142篇 |
2005年 | 3045篇 |
2004年 | 2829篇 |
2003年 | 2702篇 |
2002年 | 2497篇 |
2001年 | 848篇 |
2000年 | 868篇 |
1999年 | 700篇 |
1998年 | 312篇 |
1997年 | 250篇 |
1996年 | 252篇 |
1995年 | 207篇 |
1994年 | 183篇 |
1993年 | 154篇 |
1992年 | 346篇 |
1991年 | 305篇 |
1990年 | 260篇 |
1989年 | 264篇 |
1988年 | 205篇 |
1987年 | 234篇 |
1986年 | 226篇 |
1985年 | 212篇 |
1984年 | 163篇 |
1983年 | 128篇 |
1982年 | 114篇 |
1981年 | 111篇 |
1980年 | 86篇 |
1979年 | 133篇 |
1978年 | 86篇 |
1977年 | 98篇 |
1975年 | 91篇 |
1974年 | 96篇 |
1972年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
2.
3.
Sergio Barroilhet Adrián Cano-Prous Salvador Cervera-Enguix Maria João Forjaz Francisco Guillén-Grima 《Social psychiatry and psychiatric epidemiology》2009,44(12):1051-1065
Introduction
This paper presents the results of a study on the psychometric properties of an authorized Spanish version of the McMaster Family Assessment Device, a self-report measure of family functioning. 相似文献4.
5.
A young patient had an auriculo-ventricular block and a distal myopathy with muscle biopsy findings suggestive of inclusion body myositis. What was most unusual was the presence of numerous sarcoplasmic bodies identified as desmin by electron microscopy and immunocytochemistry. The nosological situation of this condition is discussed. 相似文献
6.
Raúl González-García Francisco J Rodríguez-Campo Verónica Escorial-Hernández Mario F Mu?oz-Guerra Jesús Sastre-Pérez Luis Naval-Gías José L Gil-Díez Usandizaga 《Journal of oral and maxillofacial surgery》2006,64(11):1587-1591
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique. 相似文献
7.
Catherine Guette Christian Legros Guewen Tournois Max Goyffon Marie-Louise Célérier 《Toxicon》2006,47(6):640-649
In order to establish a venom fingerprint and a peptide profile of the Lasiodora parahybana tarantula venom gland, we used conventional methods such as reversed phase liquid chromatography coupled to an electrospray-ionisation hybrid quadrupole time of flight mass spectrometer (LC/ESI-QqTOFMS), matrix-assisted laser desorption/ionization time-of-flight-MS (MALDI-TOFMS) and direct study of L. parahybana venom by nanospray-ionization QqTOFMS (nanoESI-QqTOFMS) and a new technology for the direct analysis of fresh tissues using MALDI-TOFMS. The analysis of the crude venom allowed the characterization of specific juvenile and adult biomarkers. In situ MALDI analysis of L. parahybana venom gland sections revealed different peptide expression levels all along the gland and non-processed peptide precursors, demonstrating the power of the method for the dynamic investigation of peptide evolution in the venom gland of spiders. 相似文献
8.
9.
F Roche S Celle V Pichot J-C Barthélémy E Sforza 《The European respiratory journal》2007,29(6):1206-1211
The prevalence of obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is underestimated and its diagnosis is costly and restricted to specialised sleep laboratories. The frequency component of interbeat interval increment (III) has been proposed as a simple and inexpensive diagnostic tool in OSAHS. In a set of 150 patients with clinically suspected sleep-related breathing disorder, the actual predictive accuracy of the power spectral density of the III of the very low frequencies (%VLFI) was analysed by comparing with the apnoea/hypopnoea index (AHI), as assessed by synchronised polysomnography. OSAHS was defined in 100 patients according to an AHI>or=15 events.h(-1). Receiver operator characteristic curves built for %VLFI confirmed that this variable was able to separate OSAHS positive from OSAHS negative with statistical significance. Using an appropriate threshold (>4%), %VLFI demonstrated a positive predictive value of 80%. Misclassification of false-positive subjects occurred when the patient presented significant sleep discontinuity and sleep fragmentation (sleep fragmentation index>or=50 events.h(-1)) related to insomnia or periodic limb movements. A power spectral density of the interbeat interval increment of very low frequencies>4% allowed correct classification of obstructive sleep apnoea/hypopnoea syndrome when the clinical history suggested sleep-related breathing disorders and when moderate-to-severe cases are considered. Higher power spectral density of the interbeat interval increment of very low frequencies may also indicate disrupted sleep in the absence of clear clinical symptoms of sleep apnoea/hypopnoea syndrome. 相似文献
10.