全文获取类型
收费全文 | 156402篇 |
免费 | 10311篇 |
国内免费 | 781篇 |
专业分类
耳鼻咽喉 | 1429篇 |
儿科学 | 3973篇 |
妇产科学 | 2845篇 |
基础医学 | 21053篇 |
口腔科学 | 3686篇 |
临床医学 | 14970篇 |
内科学 | 33701篇 |
皮肤病学 | 2904篇 |
神经病学 | 15085篇 |
特种医学 | 6210篇 |
外国民族医学 | 7篇 |
外科学 | 23382篇 |
综合类 | 1924篇 |
现状与发展 | 2篇 |
一般理论 | 162篇 |
预防医学 | 11460篇 |
眼科学 | 3238篇 |
药学 | 10593篇 |
2篇 | |
中国医学 | 247篇 |
肿瘤学 | 10621篇 |
出版年
2023年 | 831篇 |
2022年 | 1264篇 |
2021年 | 2876篇 |
2020年 | 1995篇 |
2019年 | 2894篇 |
2018年 | 3508篇 |
2017年 | 2728篇 |
2016年 | 3114篇 |
2015年 | 3577篇 |
2014年 | 5120篇 |
2013年 | 6910篇 |
2012年 | 10619篇 |
2011年 | 11250篇 |
2010年 | 6432篇 |
2009年 | 6140篇 |
2008年 | 10360篇 |
2007年 | 11000篇 |
2006年 | 10479篇 |
2005年 | 10725篇 |
2004年 | 10125篇 |
2003年 | 9610篇 |
2002年 | 9039篇 |
2001年 | 1614篇 |
2000年 | 1228篇 |
1999年 | 1720篇 |
1998年 | 2155篇 |
1997年 | 1685篇 |
1996年 | 1464篇 |
1995年 | 1324篇 |
1994年 | 1180篇 |
1993年 | 1137篇 |
1992年 | 885篇 |
1991年 | 883篇 |
1990年 | 699篇 |
1989年 | 678篇 |
1988年 | 626篇 |
1987年 | 630篇 |
1986年 | 568篇 |
1985年 | 584篇 |
1984年 | 686篇 |
1983年 | 580篇 |
1982年 | 783篇 |
1981年 | 710篇 |
1980年 | 620篇 |
1979年 | 388篇 |
1978年 | 389篇 |
1977年 | 418篇 |
1976年 | 352篇 |
1975年 | 304篇 |
1974年 | 257篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Thomas Teltzrow Franz-Josef Kramer Andrea Schulze Carola Baethge Peter Brachvogel 《Journal of cranio-maxillo-facial surgery》2005,33(5):307-313
INTRODUCTION: The aim of this study was to review complications in a series of 1264 consecutive patients who were operated in a single centre during a 20-year-period. MATERIAL AND METHODS: Complications were documented, their incidences calculated and compared with data from the literature. RESULTS: In 35 patients (2.8%) infection developed requiring extraoral incision and drainage; in 27 patients (2.1%) the inferior alveolar nerve was inadvertently cut; 18 patients (1.4%) had to undergo re-operation due to bending or fracture of osteosynthesis material; 15 patients (1.2%) suffered from bleeding complications; in 12 patients (0.9%) an unfavourable split occurred. In 8 patients (0.6%) foreign bodies were left in situ; in 7 patients a partial weakness of the facial nerve occurred, which was permanent in 1 patient. Six patients (0.5%) with a significantly higher age than average (mean: 33.6 years in comparison with 23.1 years) developed non-union at the site of osteotomy, and the mandible had to be bone grafted. Two patients (0.2%) developed osteomyelitis, and in one patient airway problems led to a need for tracheostomy (0.1%). CONCLUSION: Although some of these complications of bilateral sagittal split with osteotomy carry severe limitations in health related quality of life, it remains an overall safe procedure, demanding, however, comprehensive informed consent. Good knowledge of technical reasons for these complications should help to reduce their incidence. 相似文献
82.
83.
Benjamin H. S. Lau Sharon K. Riesen Kim P. Truong Esther W. Lau Peter Rohdewald Ray A. Barreta 《The Journal of asthma》2004,41(8):825-832
A randomized, placebo-controlled, double-blind study involving 60 subjects, aged 6-18 years old, was conducted over a period of 3 months to determine the effect of Pycnogenol® (a proprietary mixture of water-soluble bioflavonoids extracted from French maritime pine) on mild-to-moderate asthma. After baseline evaluation, subjects were randomized into two groups to receive either Pycnogenol® or placebo. Subjects were instructed to record their peak expiratory flow with an Assess® Peak Flow Meter each evening. At the same time, symptoms, daily use of rescue inhalers (albuterol), and any changes in oral medications were also recorded. Urine samples were obtained from the subjects at the end of the run-in period, and at 1-, 2-, and 3-month visits. Urinary leukotriene C4/D4/E4 was measured by an enzyme immunoassay. Compared with subjects taking placebo, the group who took Pycnogenol® had significantly more improvement in pulmonary functions and asthma symptoms. The Pycnogenol® group was able to reduce or discontinue their use of rescue inhalers more often than the placebo group. There was also a significant reduction of urinary leukotrienes in the Pycnogenol® group. The results of this study demonstrate the efficacy of Pycnogenol® as an adjunct in the management of mild-to-moderate childhood asthma. 相似文献
84.
Peter L Weissberg 《Journal of nuclear medicine》2004,45(11):1794-1795
85.
Claudia Brogsitter Thomas Grüning Reiner Weise Peter Wielepp Oliver Lindner Reiner K?rfer Wolfgang Burchert 《Journal of nuclear medicine》2005,46(1):19-24
(18)F-FDG PET is an important diagnostic tool for detecting myocardial viability in patients with coronary artery disease. In combination with perfusion scanning, (18)F-FDG PET allows differentiation between reversibly and irreversibly damaged myocardium and selection of patients likely to benefit from revascularization. Viability PET is usually performed in two-dimensional (2D) mode. Taking into account the rising number of three-dimensional (3D)-only scanners, a validation of 3D acquisition is required. METHODS: Twenty-one patients with coronary artery disease referred for (18)F-FDG PET underwent an imaging protocol of nongated 2D (2D-NG) and gated 2D (2D-G) acquisitions for 15 min each, followed by 3D gated acquisitions for 10 min (3D-10) and 5 min (3D-5), using an ECAT Exact HR+ scanner. Results were analyzed using a 20-segment polar map in terms of activity concentration (Bq/mL), viability (50% uptake threshold), regional activity distribution, visual assessment of viability based on a 3-point rating scale, and left ventricular ejection fraction. RESULTS: Activity concentration measured in each segment with 2D-G, 3D-10, and 3D-5 showed a good linear correlation with 2D-NG. Quantitative viability assessment with 3D-5 gave a sensitivity of 84% and a specificity of 98%, compared with 2D-NG. No differences in regional activity distribution and visual viability assessment were found between the various protocols. Left ventricular ejection fractions obtained with 3D-10 and 3D-5 showed a good linear correlation with those measured with 2D-G. CONCLUSION: An ECG-gated 3D imaging protocol gave results comparable to those of 2D acquisition with regard to absolute and regional myocardial activity distribution, left ventricular function, and visual viability assessment. Sensitivity for viability assessment with a 50% uptake threshold was significantly less with 3D, but specificity was maintained. This protocol delivers a clinical performance nearly equivalent to that of 2D acquisition. 相似文献
86.
87.
Ivan Tkác Pierre-Gilles Henry Peter Andersen C Dirk Keene Walter C Low Rolf Gruetter 《Magnetic resonance in medicine》2004,52(3):478-484
An efficient shim system and an optimized localization sequence were used to measure in vivo 1H NMR spectra from cerebral cortex, hippocampus, striatum, and cerebellum of C57BL/6 mice at 9.4 T. The combination of automatic first- and second-order shimming (FASTMAP) with strong custom-designed second-order shim coils (shim strength up to 0.04 mT/cm2) was crucial to achieve high spectral resolution (water line width of 11-14 Hz). Requirements for second-order shim strengths to compensate field inhomogeneities in the mouse brain at 9.4 T were assessed. The achieved spectral quality (resolution, S/N, water suppression, localization performance) allowed reliable quantification of 16 brain metabolites (LCModel analysis) from 5-10-microL brain volumes. Significant regional differences (up to 2-fold, P < 0.05) were found for all quantified metabolites but Asp, Glc, and Gln. In contrast, 1H NMR spectra measured from the striatum of C57BL/6, CBA, and CBA/BL6 mice revealed only small (<13%, P < 0.05) interstrain differences in Gln, Glu, Ins, Lac, NAAG, and PE. It is concluded that 1H NMR spectroscopy at 9.4 T can provide precise biochemical information from distinct regions of the mouse brain noninvasively that can be used for monitoring of disease progression and treatment as well as phenotyping in transgenic mice models. 相似文献
88.
89.
90.
Peter Jecker Lisa A. Orloff Miriam Wohlfeil Wolf J. Mann 《European archives of oto-rhino-laryngology》2006,263(7):664-667
Chronic polypoid rhinosinusitis (CRS) is a common disease, affecting approximately 16% of the adult population in the US every year. In addition to many well known predisposing factors, an association with reflux disease is hypothesized. Such an association might explain the recurrence of polyposis in the face of improved surgical techniques and postsurgical treatment of CRS. At present it is unclear whether extraesophageal reflux directly injures the sinus mucosa, whether gastroesophageal reflux leads to vagus-mediated neuroinflammatory changes, or whether both mechanisms occur separately or simultaneously. In patients suffering from recurrent CRS (n=20) and healthy volunteers (n=20), ambulatory 24 h two channel pH testing was performed. The number of reflux events, the fraction of the total time during which pH was below 4, and the reflux area index (RAI) were determined in the esophagus as well as in the hypopharynx. Patients with recurrent CRS had significantly more reflux events in the esophagus and the fraction of pH<4 and the RAI were increased up to 10-fold compared to healthy volunteers. In contrast to the esophagus, these differences were not observed in the hypopharynx. Recurrent CRS is often associated with GERD but not with EER. Recurrent disease or prolonged recovery after surgery should raise the suspicion of reflux disease as a possible triggering factor. Because GERD itself cannot be diagnosed by laryngoscopy, and because of the subjectivity of symptoms such as heartburn, the otolaryngologist should consider double-probe pH testing as the diagnostic procedure of choice. 相似文献