全文获取类型
收费全文 | 2968篇 |
免费 | 152篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 79篇 |
妇产科学 | 29篇 |
基础医学 | 523篇 |
口腔科学 | 59篇 |
临床医学 | 266篇 |
内科学 | 660篇 |
皮肤病学 | 80篇 |
神经病学 | 293篇 |
特种医学 | 175篇 |
外科学 | 379篇 |
综合类 | 9篇 |
预防医学 | 171篇 |
眼科学 | 33篇 |
药学 | 166篇 |
中国医学 | 4篇 |
肿瘤学 | 198篇 |
出版年
2023年 | 17篇 |
2022年 | 34篇 |
2021年 | 68篇 |
2020年 | 44篇 |
2019年 | 57篇 |
2018年 | 60篇 |
2017年 | 44篇 |
2016年 | 61篇 |
2015年 | 86篇 |
2014年 | 112篇 |
2013年 | 155篇 |
2012年 | 249篇 |
2011年 | 232篇 |
2010年 | 136篇 |
2009年 | 123篇 |
2008年 | 213篇 |
2007年 | 179篇 |
2006年 | 176篇 |
2005年 | 150篇 |
2004年 | 123篇 |
2003年 | 135篇 |
2002年 | 123篇 |
2001年 | 49篇 |
2000年 | 40篇 |
1999年 | 47篇 |
1998年 | 47篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 24篇 |
1991年 | 19篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 22篇 |
1987年 | 20篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1931年 | 4篇 |
1926年 | 6篇 |
1925年 | 6篇 |
1919年 | 4篇 |
排序方式: 共有3137条查询结果,搜索用时 15 毫秒
1.
Heiko Sch?der Diane L Carlson Dennis H Kraus Hilda E Stambuk Mithat G?nen Yusuf E Erdi Henry W D Yeung Andrew G Huvos Jatin P Shah Steven M Larson Richard J Wong 《Journal of nuclear medicine》2006,47(5):755-762
(18)F-FDG PET has a high accuracy in staging head and neck cancer, but its role in patients with clinically and radiographically negative necks (N0) is less clear. In particular, the value of combined PET/CT has not been determined in this group of patients. METHODS: In a prospective study, 31 patients with oral cancer and no evidence of lymph node metastases by clinical examination or CT/MRI underwent (18)F-FDG PET/CT before elective neck dissection. PET/CT findings were recorded by neck side (left or right) and lymph node level. PET/CT findings were compared with histopathology of dissected nodes, which was the standard of reference. RESULTS: Elective neck dissections (26 unilateral, 5 bilateral; a total of 36 neck sides), involving 142 nodal levels, were performed. Only 13 of 765 dissected lymph nodes harbored metastases. Histopathology revealed nodal metastases in 9 of 36 neck sides and 9 of 142 nodal levels. PET was TP in 6 nodal levels (6 neck sides), false-negative in 3 levels (3 neck sides), true-negative in 127 levels (23 neck sides), and false-positive in 6 levels (4 neck sides). The 3 false-negative findings occurred in metastases smaller than 3 mm or because of inability to distinguish between primary tumor and adjacent metastasis. TP and false-positive nodes exhibited similar standardized uptakes (4.8 +/- 1.1 vs. 4.2 +/- 1.0; P = not significant). Sensitivity and specificity were 67% and 85% on the basis of neck sides and 67% and 95% on the basis of number of nodal levels, respectively. If a decision regarding the need for neck dissection had been based solely on PET/CT, 3 false-negative necks would have been undertreated, and 4 false-positive necks would have been overtreated. CONCLUSION: (18)F-FDG PET/CT can identify lymph node metastases in a segment of patients with oral cancer and N0 neck. A negative test can exclude metastatic deposits with high specificity. Despite reasonably high overall accuracy, however, the clinical application of PET/CT in the N0 neck may be limited by the combination of limited sensitivity for small metastatic deposits and a relatively high number of false-positive findings. The surgical management of the N0 neck should therefore not be based on PET/CT findings alone. 相似文献
2.
Sabine Elisabeth Gabor Heiko Renner Alfred Maier Freyja Maria Smolle Jüttner 《European journal of cardio-thoracic surgery》2005,28(3):502-503
A 21-year-old female with chronic membranoproliferative nephritis was admitted for suspected esophageal disruption and asthma after severe, prolonged vomiting. At the time of admission she presented with dyspnea, tachypnea, arterial hypotension and tachycardia. Physical examination showed discrete signs of ectopic air at the neck and distended cervical veins. CT-scan of the chest showed severe mediastinal emphysema with compression of the right atrium. After cervical mediastinotomy the cardiorespiratory parameters normalized immediately. Esophagoscopy showed multiple longitudinal mucosal tears between 25 and 45 cm; fluoroscopically, there was no leakage of contrast medium. Following conservative treatment the patient recovered completely and was discharged on day 8. 相似文献
3.
Nicolas Feltgen Heiko Mueller Beat Ott Martin Frenz Jens Funk 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2003,241(2):94-100
PURPOSE:. To compare the efficacy of endoscopic erbium:YAG laser goniopuncture in glaucoma treatment to trabeculectomy, both methods as adjuncts to cataract surgery. METHODS:. Fifty-nine eyes of 59 glaucoma patients with coexistent cataract were treated by phacoemulsification and endoscopic Er:YAG goniopuncture in a combined fashion. The primary study endpoints were intraocular pressure (IOP), number of antiglaucomatous drugs, postoperative complications, hospitalisation time and visual acuity at 1 year after surgery. To date, 24 eyes have finished the 1-year follow-up. This prospective treatment arm was compared to a retrospective inclusion-matched control group treated by trabeculectomy and cataract surgery in a single procedure. RESULTS:. In the laser-treated group, the mean IOP dropped by 30% from 23.4+/-3.7 mmHg to 16.3+/-6 mmHg ( P<0.0001) after 12 months. Without reoperation, treatment was successful in 71% of these eyes. In the control group, the IOP decreased by 33.5% from 22.7+/-3.3 mmHg to 15.1+/-3.8 mmHg ( P<0.0001). The success rate without reoperation was 46%. The number of antiglaucomatous drugs needed decreased from 1.48+/-0.95 to 0.48+/-0.7 ( P<0.0001) in the laser-treated group and from 2.0+/-0.9 to 0.39+/-0.6 ( P<0.0001) in the control group. Postoperative complications were found more frequently in the control group ( P<0.0001). Hospitalisation was shorter in the laser group ( P<0.0001). Postoperative visual acuity was lower in the control group ( P=0.004). CONCLUSION:. Combined Er:YAG goniopuncture and cataract surgery lowers the IOP to an extent comparable to combined trabeculectomy and cataract surgery. Due to fewer postoperative complications, Er:YAG goniopuncture seems to be superior to standard fistulation surgery as the primary approach within the first year. 相似文献
4.
S Ben Becher J el Mabrouk A Debbiche A Hammou N Ghram S Makni T Boudhina 《Archives fran?aises de pédiatrie》1992,49(9):799-802
BACKGROUND. Schwartz-Jampel syndrome is a rare disorder inherited as an autosomal recessive trait and characterized by growth retardation, multiple skeletal abnormalities, myotonia-like muscle disorders and unusual facies. CASE REPORTS. Case n. 1: A boy, aged 3 years 4 months, was admitted for acute respiratory disease. His main abnormalities included rigid facial expression, blepharophimosis, puckered lips, short neck, pectus carinatum, acetabular dysplasia with coxa vara, platyspondyly and marked growth retardation. There was a continuous muscle fiber activity at rest, with abnormal discharges originating in the muscle component of the neuromuscular junction. Blood investigations revealed low values of IgA. The child died at 4 years. Case n. 2: The sister of case n. 1 was examined at 14 months of age. She presented milder facies abnormalities, difficulties of gait because of stiff hips, muscular hypertrophy, coxa vara and growth retardation. X-rays showed skeletal abnormalities and the electromyogram was similar to those of her brother. She had dislocation of her optic lens. CONCLUSION. These 2 sibs have the characteristic manifestations of Schwartz-Jampel syndrome. Parental consanguinity was also present. The IgA deficiency observed in case n. 1 and the lens dislocation in case n. 2 have both been occasionally reported in this syndrome. 相似文献
5.
6.
7.
Genetic ablation of the t-SNARE SNAP-25 distinguishes mechanisms of neuroexocytosis. 总被引:12,自引:0,他引:12
Philip Washbourne Peter M Thompson Mario Carta Edmar T Costa James R Mathews Guillermina Lopez-Benditó Zoltán Molnár Mark W Becher C Fernando Valenzuela L Donald Partridge Michael C Wilson 《Nature neuroscience》2002,5(1):19-26
Axon outgrowth during development and neurotransmitter release depends on exocytotic mechanisms, although what protein machinery is common to or differentiates these processes remains unclear. Here we show that the neural t-SNARE (target-membrane-associated-soluble N-ethylmaleimide fusion protein attachment protein (SNAP) receptor) SNAP-25 is not required for nerve growth or stimulus-independent neurotransmitter release, but is essential for evoked synaptic transmission at neuromuscular junctions and central synapses. These results demonstrate that the development of neurotransmission requires the recruitment of a specialized SNARE core complex to meet the demands of regulated exocytosis. 相似文献
8.
Mobilization and evolutionary history of miniature inverted-repeat transposable elements (MITEs) in Beta vulgaris L. 总被引:1,自引:0,他引:1
Gerhard Menzel Daryna Dechyeva Heiko Keller Cornelia Lange Heinz Himmelbauer Thomas Schmidt 《Chromosome research》2006,14(8):831-844
We have identified three families of miniature inverted-repeat transposable elements (VulMITEs) in the genome of sugar beet
(Beta vulgaris L.), evidently derived from a member of the Vulmar family of mariner transposons. While VulMITEs I are typical stowaway-like MITEs, VulMITEs II and VulMITEs III are rearranged stowaway elements of increased size. The integration of divergent moderately and highly repetitive sequences into VulMITEs II and,
in particular in VulMITEs III, respectively, shows that amplification of repetitive DNA by MITEs contribute to the increase
of genome size with possible implications for plant genome evolution. Fluorescent in-situ hybridization (FISH), for the first time visualizing stowaway MITE distribution on plant chromosomes, revealed a dispersed localization of VulMITEs along all B. vulgaris chromosomes. Analysis of the flanking sequences identified a dispersed repeat as target site for the integration of the stowaway element VulMITE I. Recent transposition of VulMITE I, which most likely occurred during the domestication of cultivated beets, was concluded from insertional polymorphisms between
different B. vulgaris cultivars and species.
†Sequence data from this article have been deposited in the EMBL/GenBank Data Library under the accession nos. AM231630-AM231653
and AM259123-AM259125. 相似文献
9.
A 54-year old man presented with multiple pulmonary emboli and an incidental finding of a huge left ventricular thrombus. Transthoracic echo images demonstrated a globally dilated heart with very poor left ventricular function. It was elected to manage the patient medically, and he was commenced on warfarin therapy, resulting in completed resolution of the thrombus over 10 weeks. No underlying cause was found and he did not experience any further embolic events. This illustrates a rare case of a large ventricular thrombus in a patient with no underlying risk factors. 相似文献
10.
Andreas Machner Harry Merk Roland Becker Kerstin Rohkohl Heiko Wissel G za Pap 《Acta orthopaedica》2003,74(1):85-88
A proprioceptive deficit is an important determinant of disability in various shoulder disorders, such as instability and osteoarthrosis. In 15 patients with impingement syndrome stage II (Neer 1983), who were treated by arthroscopic subacromial decompression, we measured movement sense by determining threshold levels for the perception of motion of the shoulder. The patients were placed in a specially designed chair allowing continuous passive motion of the shoulder joint, while avoiding cutaneous, auditory and visual stimuli. To assess movement detection thresholds, passive abduction movements of the shoulder were performed at a starting angle of 60°, an amplitude of 10° and an angular velocity of 1.3°/s. Before surgery, all patients had higher threshold levels for the perception of motion in their affected shoulders then in the other side. After decompression, proprioception had improved on the decompressed side, but was unchanged on the other side. 相似文献