全文获取类型
收费全文 | 1771篇 |
免费 | 99篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 94篇 |
妇产科学 | 57篇 |
基础医学 | 136篇 |
口腔科学 | 12篇 |
临床医学 | 199篇 |
内科学 | 309篇 |
皮肤病学 | 39篇 |
神经病学 | 168篇 |
特种医学 | 169篇 |
外科学 | 319篇 |
综合类 | 49篇 |
预防医学 | 163篇 |
眼科学 | 24篇 |
药学 | 82篇 |
中国医学 | 2篇 |
肿瘤学 | 64篇 |
出版年
2023年 | 12篇 |
2021年 | 14篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2018年 | 26篇 |
2017年 | 23篇 |
2016年 | 15篇 |
2015年 | 21篇 |
2014年 | 28篇 |
2013年 | 46篇 |
2012年 | 58篇 |
2011年 | 47篇 |
2010年 | 44篇 |
2009年 | 47篇 |
2008年 | 65篇 |
2007年 | 77篇 |
2006年 | 69篇 |
2005年 | 70篇 |
2004年 | 61篇 |
2003年 | 77篇 |
2002年 | 69篇 |
2001年 | 41篇 |
2000年 | 44篇 |
1999年 | 39篇 |
1998年 | 38篇 |
1997年 | 51篇 |
1996年 | 40篇 |
1995年 | 34篇 |
1994年 | 33篇 |
1993年 | 24篇 |
1992年 | 41篇 |
1991年 | 53篇 |
1990年 | 38篇 |
1989年 | 56篇 |
1988年 | 41篇 |
1987年 | 32篇 |
1986年 | 26篇 |
1985年 | 32篇 |
1984年 | 22篇 |
1983年 | 27篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 16篇 |
1978年 | 14篇 |
1977年 | 16篇 |
1976年 | 9篇 |
1974年 | 8篇 |
1936年 | 8篇 |
1922年 | 8篇 |
排序方式: 共有1897条查询结果,搜索用时 31 毫秒
11.
The tensor fascia lata myocutaneous flap provides a reliable autogenous building block for anatomical lower abdominal wall reconstruction. Preservation of innervation allows maintenance of voluntary motor control and protective sensation. The excellent blood supply of this flap is particularly helpful in reconstructing previously irradiated areas. A one-stage repair is possible, leaving minimal secondary defect. We describe 4 patients illustrating the uses and versatilty of this flap. Anatomy, operative procedures, and indications for delay are also discussed. 相似文献
12.
Retrorenal colon: implications for percutaneous diskectomy 总被引:1,自引:0,他引:1
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary. 相似文献
13.
14.
The effect of ACTH on the expression of major histocompatibility complex (MHC) class II (I-A) glycoprotein by murine peritoneal macrophages was evaluated. ACTH suppressed the expression of I-A by macrophages in a time- and dose-dependent manner. ACTH mediated its effect by decreasing the level of I-A mRNA. ACTH suppressed the expression of I-A by macrophages from mice that are susceptible to the in vivo growth of mycobacteria but did not affect the expression of I-A by macrophages from Mycobacterium bovis strain (BCG)-resistant mice. The concentrations of ACTH required to suppress I-A expression were greater than that required for an effect on adrenal steroid production and may be related to the localized production of ACTH by lymphocytes and macrophages. 相似文献
15.
J M Pearl H Laks S W Barthel E M Kaczer D K Loo D C Drinkwater P Chang 《The Journal of thoracic and cardiovascular surgery》1992,104(6):1702-1708
The partial Fontan procedure has become an accepted alternative for the high-risk candidate. Creation of a small right-to-left shunt will lower the systemic venous pressure and improve systemic cardiac output while maintaining an acceptable systemic arterial saturation. However, because of variations in patient size and postoperative transpulmonary gradient, proper sizing of the residual defect is difficult. We have therefore conducted a series of experiments on a model that simulates the blood flow across interatrial defects of varying sizes at several pressure gradients. We used porcine blood to develop guidelines for the sizing of the residual defect. Our results demonstrate a linear relationship between flow and pressure gradient across all hole sizes tested. In addition, there was a linear relationship between atrial septal defect size and flow at each pressure gradient. Our data show that the Gorlin formula predictions overestimated flow by 10% to 40%. It is evident from these data that relatively small changes in the size of the atrial septal defect or in the pressure gradient result in significant changes in flow. Therefore we advocate the use of an adjustable interatrial communication such as the snare-controlled adjustable atrial septal defect for patients undergoing partial Fontan procedures. 相似文献
16.
17.
J M Pearl H Laks D C Drinkwater A Meneshian S M Martin M Curzan P A Chang 《The Annals of thoracic surgery》1992,54(6):1144-1150
Blood cardioplegia is considered by many to be the preferred solution for myocardial protection. Proposed benefits include the ability to deliver oxygen and the ability to maintain metabolic substrate stores. However, the decreased capacity of blood to release oxygen at hypothermic conditions as well as the presence of deleterious leukocytes, platelets, and complement may limit complete functional recovery. Fluosol is an asanguineous solution with the ability to bind and release oxygen linearly at low temperatures. Neonatal piglet hearts (24 to 48 hours old) were excised and supported on an isolated, blood-perfused working heart model. After baseline stroke-work index was determined, hearts were arrested with either normocalcemic blood cardioplegia (group 1, n = 8) or normocalcemic Fluosol cardioplegia (group 2, n = 8). Cold cardioplegia was administered at 45 mm Hg every 20 minutes for 2 hours. Hearts were then reperfused with whole blood. Functional recovery, expressed as percent of control stroke-work index, was determined 60 minutes after reperfusion at left atrial pressures of 3, 6, 9, and 12 mm Hg. Functional recovery at 60 minutes was similar between group 1 (95%, 93%, 93%, 88%) and group 2 (100%, 94%, 94%, 95%) at left atrial pressures of 3, 6, 9, and 12 mm Hg, respectively. Mean lactate consumption 5 minutes after reperfusion was significantly greater (p = 0.0001) in group 1 (31.8 +/- 6.3 micrograms.min-1 x g-1) than in group 2 (-0.59 +/- 0.1 microgram.min-1 x g-1), indicating superior metabolic recovery in the blood cardioplegia hearts. Edema formation, as determined both by water content (group 1, 81.10%; group 2, 81.63%) and by electron microscopy, was not significantly different between groups.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
18.
PL Macken FRACO FRACS CJ Pavlin FRCS R Tuli MD GE Trope PhD FRCS 《Clinical & experimental ophthalmology》1995,23(3):217-220
Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy. 相似文献
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy. 相似文献
19.
1,6—二磷酸果糖对手术后应激病人应用全肠外营养支持效果的影响 总被引:3,自引:1,他引:2
本文在胃癌行全胃或胃大部切除术引起的中等程度应激病人,随机分组对比观察了全肠外营养或TPN加用1,6-二磷酸果糖的效果。结果显示,与单纯TPN相比,TPN加用FDP后血清皮质醇和胰高血糖素等应激激素水平有所下降,尿中3-甲基组氨酸排出减少,累积氮平衡增加。 相似文献
20.