全文获取类型
收费全文 | 3905篇 |
免费 | 224篇 |
国内免费 | 124篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 179篇 |
妇产科学 | 17篇 |
基础医学 | 130篇 |
口腔科学 | 3篇 |
临床医学 | 382篇 |
内科学 | 932篇 |
皮肤病学 | 2篇 |
神经病学 | 508篇 |
特种医学 | 377篇 |
外科学 | 944篇 |
综合类 | 440篇 |
预防医学 | 69篇 |
眼科学 | 52篇 |
药学 | 122篇 |
中国医学 | 28篇 |
肿瘤学 | 43篇 |
出版年
2024年 | 7篇 |
2023年 | 81篇 |
2022年 | 119篇 |
2021年 | 155篇 |
2020年 | 153篇 |
2019年 | 130篇 |
2018年 | 116篇 |
2017年 | 120篇 |
2016年 | 124篇 |
2015年 | 126篇 |
2014年 | 226篇 |
2013年 | 198篇 |
2012年 | 163篇 |
2011年 | 197篇 |
2010年 | 132篇 |
2009年 | 164篇 |
2008年 | 163篇 |
2007年 | 160篇 |
2006年 | 165篇 |
2005年 | 161篇 |
2004年 | 123篇 |
2003年 | 104篇 |
2002年 | 98篇 |
2001年 | 84篇 |
2000年 | 98篇 |
1999年 | 73篇 |
1998年 | 74篇 |
1997年 | 66篇 |
1996年 | 65篇 |
1995年 | 66篇 |
1994年 | 74篇 |
1993年 | 40篇 |
1992年 | 38篇 |
1991年 | 29篇 |
1990年 | 25篇 |
1989年 | 35篇 |
1988年 | 46篇 |
1987年 | 22篇 |
1986年 | 23篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 15篇 |
1982年 | 27篇 |
1981年 | 26篇 |
1980年 | 17篇 |
1979年 | 16篇 |
1978年 | 19篇 |
1977年 | 10篇 |
1974年 | 10篇 |
1973年 | 4篇 |
排序方式: 共有4253条查询结果,搜索用时 0 毫秒
1.
《Journal of vascular and interventional radiology : JVIR》2020,31(7):1069-1073
This report describes a technique for measuring lung shunt fraction (LSF) twice in a single session during planning arteriography for radioembolization using low and standard dose technetium-99m macroaggregated albumin (99mTc-MAA). A patient with a 16.0 cm hepatocellular carcinoma and LSF of 70% was treated with lenvatinib for 4 weeks. Planning arteriography with administration of 0.5 millicuries of 99mTc-MAA was then performed. Arterial access was maintained while the LSF was calculated, which was persistently elevated at 54%. Embolization of arteriovenous shunts was performed during the same session and 5.0 millicuries of 99mTc-MAA were administered. The repeat LSF was 29%. Successful radioembolization was subsequently performed. 相似文献
2.
3.
PULMONARY BLOOD DISTRIBUTION AFTER TOTAL CAVOPULMONARY CONNECTION OF DIFFERENT TYPES 总被引:2,自引:0,他引:2
Objective. To assess the feature of pulmonary blood flow distribution after total cavopulmonary connection (TCPC) of different types, and to provide the selection of the best type .Methods. Thirty-two consecutive survival patients after TCPC underwent radionuclide lung perfusion imaging. According to the radionuclide counts in the left and right lungs, analyses of the distribution of blood flow from superior venous cava (SVC) and inferior venous cava (IVC) and the whole pulmonary blood flow in both lungs were made. All patients were divided into 4 groups by the the anastomosis between IVC and pulmonary artery.Results. Group Ⅰ: The flow ratio of the IVC to left lung was greater than that to the right lung , P≤0. 01; the flow ratio of the SVC to right lung was greater than that to the left lung, P≤0. 01; and the whole pulmonary blood flow went dominantly to the left lung, P≤0. 05, which is not in line with physiological distribution. Group Ⅱ: the flows from the SVC and IVC were mixed in the middle of 相似文献
4.
H. Inaba M.D. J. Sato H. Uchida M. Sakurada T. Ohwada T. Mizuguchi 《Acta anaesthesiologica Scandinavica》1988,32(5):374-378
Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury. 相似文献
5.
José Ignacio Bilbao Mercedes Arias Jesús María Longo Pedro Luis Alejandre María Teresa Betés Arlette María Elizalde 《Cardiovascular and interventional radiology》1997,20(2):149-153
Percutaneous embolization of large portosystemic collaterals was performed in three patients following placement of a transjugular
intrahepatic portosystemic shunt in order to improve hepatopetal portal flow. Improved hepatic portal perfusion was achieved
in these cases, thereby theoretically reducing the risk of chronic hepatic encephalopathy. 相似文献
6.
本文报告一种新的改良式远端脾肾静脉分流术,即脾静脉与左肾静脉侧侧吻合、脾静脉远端结扎,再将胃冠状静脉结扎。作者经治7例,初步观察疗效较好,术后无死亡,无复发出血,无肝性脑病发生。本文对这种手术的步骤和优点进行了讨论和分析。 相似文献
7.
Dynamic aspects of expanding cava septi pellucidi et Vergae 总被引:2,自引:0,他引:2
Summary Two paediatric patients with expanding cysts of the cava Vergae et septi pellucidi are presented. In the first patient, consecutive CT scans showed agrowing cavum thought to be responsible for his dramatic increase in head circumference. In the other patient, the expanding cavum was discovered because a routine skull X-ray after minor head trauma revealed marked impressiones digitatae.Both patients were successfully treated with stereotactically placed internal shunts from the cysts via the lateral ventricle to the subarachnoid space. During this procedure, contrast medium was instilled, and the cysts were visualized on postoperative CT scans.Some dynamic aspects of such expanding cava are discussed. 相似文献
8.
Adaptation of the disector method to rare small organelles in TEM sections exemplified by counting synaptic bodies in the rat pineal gland 总被引:2,自引:0,他引:2
The disector is the only objective method for quantifying particles of variable size in a given volume. With this method, cell organelles are identified on adjacent sections, but only those present in one section are counted. When counting extremely rare structures in transmission electron microscope sections (physical disector), the usual procedure of counting on electron micrographs is limited for economic reasons (e.g. micrographs highly outnumbering the investigated structures). Hence, to apply this unbiased stereological method, a modification of the physical disector concerning 3 aspects has been developed. (1) The prerequisite of screening large corresponding tissue areas (here ∼65000 μm2 ) was fulfilled by examining tissue areas along the edges of ultrathin sections. (2) The size of the counting frame was determined by measuring the lengths of the section margins (minus a guard area) by means of a Morphomat. This value was multiplied by the width of the investigated tissue zone, corresponding to the diameter of the electron microscope viewing screen. (3) Disector counting was carried out simultaneously on both sections (bidirectional disector) to improve efficiency. In the present study tiny synaptic bodies (SBs) were quantitated by disector in a rat pineal gland, yielding ∼30 SBs/1000 μm3 . By contrast, single section profile counts of SBs amounted to 90 SBs/20000 μm2 . Since the presently described adaptation of the disector is time-consuming, it is proposed to determine a proportion factor allowing to estimate number of structures per volume based on single section profile counts. This would decrease the evaluation time by more than 50%. 相似文献
9.
D. A. MOFFAT 《Clinical otolaryngology》1994,19(3):261-266
One hundred endolymphatic mastoid shunt operations in 89 patients with classical Menière's disease were analysed. The disease was bilateral in 18 patients (20%). The patients were carefully pre-selected by a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definite electrophysiological evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analysed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AAOO, 1972) and the more recent modifications of the American Academy of Otolaryngology, Head and Neck Surgery (AA-HNS, 1985). Control of the vertigo was achieved in 81% of the patients overall, in 88% of the patients with unilateral disease and in 63% of the patients with bilateral disease. A significant hearing improvement was obtained in 19% of patients, no change in 55% and hearing became worse in 26%. Tinnitus improved in 38% of patients, was unchanged in 52% and became worse in 10%. Disability was assessed and there was no disability in 44% of the patients post-operatively, some degree of disability in 48% but only 8% were severely disabled and unable to sustain gainful employment. 相似文献
10.
Oxidative breakdown of octanoic acid is maintained in patients with cirrhosis despite advanced disease 总被引:1,自引:0,他引:1
M. Van de Casteele A. Luypaerts † B. Geypens † J. Fevery Y. Ghoos† & F. Nevens 《Neurogastroenterology and motility》2003,15(2):113-120
As an octanoic acid 13CO2 breath test is frequently used to test gastric emptying of solid food, the purpose of the present study was to study whether oxidative breakdown of octanoic acid is affected by severe liver disease. The design of our study was twofold. First, cirrhotic patients (n = 82) of varying severity were compared with healthy controls (n = 17). Values of half-time, time point of maximal expiration and cumulative recovery of octanoic acid breath tests (OBT) were not significantly different between them. Secondly, cirrhotic patients (n = 10) were studied before placement of transjugular intrahepatic portosystemic shunt, 4-7 days later and 1-2 months later. Values of half-time, time point of maximal expiration and cumulative recovery of consecutive OBTs did not change significantly. The OBT may therefore be a suitable test in the future to detect delayed gastric emptying of solids in cirrhotic patients with reduced liver function and portal hypertension. 相似文献