首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   45176篇
  免费   3493篇
  国内免费   2300篇
耳鼻咽喉   1544篇
儿科学   630篇
妇产科学   219篇
基础医学   5666篇
口腔科学   1092篇
临床医学   4747篇
内科学   4313篇
皮肤病学   221篇
神经病学   8879篇
特种医学   1251篇
外国民族医学   3篇
外科学   8108篇
综合类   6280篇
预防医学   1012篇
眼科学   2666篇
药学   2499篇
  41篇
中国医学   1102篇
肿瘤学   696篇
  2024年   103篇
  2023年   703篇
  2022年   1189篇
  2021年   1770篇
  2020年   1757篇
  2019年   1505篇
  2018年   1459篇
  2017年   1701篇
  2016年   1707篇
  2015年   1642篇
  2014年   2754篇
  2013年   2749篇
  2012年   2185篇
  2011年   2416篇
  2010年   2122篇
  2009年   1998篇
  2008年   2149篇
  2007年   2159篇
  2006年   1924篇
  2005年   1630篇
  2004年   1570篇
  2003年   1373篇
  2002年   1218篇
  2001年   1081篇
  2000年   891篇
  1999年   868篇
  1998年   831篇
  1997年   756篇
  1996年   620篇
  1995年   575篇
  1994年   479篇
  1993年   467篇
  1992年   505篇
  1991年   427篇
  1990年   405篇
  1989年   345篇
  1988年   296篇
  1987年   301篇
  1986年   281篇
  1985年   380篇
  1984年   316篇
  1983年   223篇
  1982年   254篇
  1981年   212篇
  1980年   197篇
  1979年   131篇
  1978年   85篇
  1977年   84篇
  1976年   59篇
  1975年   41篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
41.

Background

There is a need for a peripheral nerve model on which surgeons-in-training can simulate the repair of nerve injuries at their own pace. Although practicing on animal models/cadavers is considered the “gold standard” of microsurgical training, the proposed model aims to provide a platform for improving the technical skills of surgical trainees prior to their practice on cadaver/animal models. In addition, this model has the potential to serve as a standardized test medium for assessing the skill sets of surgeons.

Methods

Several formulations of silicone were utilized for the design and fabrication of a model which realizes the hierarchical structure of peripheral nerves. The mechanical properties were characterized via the Universal Testing Machine; the damage caused by the needle on the entry sites was assessed through scanning electron microscopy (SEM).

Results

Mechanical properties of the formulations of silicone were tested to mimic human peripheral nerves. A formulation with 83.3?wt% silicone oil and 0.1?wt% cotton fiber was chosen to be used as nerve fascicles. Both 83.3?wt% silicone oil with cotton fiber and 66.6?wt% silicone oil without fiber provided a microsuturing response similar to that of epineurium at a wall thickness of 1?mm. SEM also confirmed that the entry of the needle did not introduce significant holes at the microsuturing sites.

Conclusions

The proposed peripheral nerve model mimicked human tissues mechanically and cosmetically, and a simulation of the repair of a fifth-degree nerve injury was achieved.  相似文献   
42.

Background

The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine.

Methods

Ultrasound-guided ulnar nerve blocks (ropivacaine 0.75% wt/vol, 3 ml, with saline 1 ml with or without dexamethasone 4 mg) were performed on three occasions in 24 male volunteers along with an i.v. injection of saline 1 ml with or without dexamethasone 4 mg. The combinations of saline and dexamethasone were as follows: control group, perineural and i.v. saline; perineural group, perineural dexamethasone and i.v. saline; i.v. group, perineural saline and i.v. dexamethasone. Sensory block was measured using a VAS in response to pinprick testing. The duration of sensory block was the primary outcome and time to onset of sensory block the secondary outcome.

Results

All 24 subjects completed the trial. The median [inter-quartile range (IQR)] duration of sensory block was 6.87 (5.85–7.62) h in the control group, 7.37 (5.78–7.93) h in the perineural group and 7.37 (6.10–7.97) h in the i.v. group (P=0.61). There was also no significant difference in block onset time between the three groups.

Conclusion

Dexamethasone 4 mg has no clinically relevant effect on the duration of sensory block provided by ropivacaine applied to the ulnar nerve.

Clinical trial registration

DRKS, 00014604; EudraCT, 2018-001221-98.  相似文献   
43.
44.
45.
Effective management and control of peri- and postoperative pain in hip surgery is essential in order to minimize the use of opioids and their adverse effects. Effective regional analgesia for hip pain is made particularly challenging by the complex innervation of the hip joint. Standard regional techniques can be associated with complications, including incomplete anesthesia, hypotension, or lower limb weakness. We present the case of a 5-year-old girl with a history of infantile cerebral palsy who underwent bilateral varus derotation osteotomy and adductor tenotomy due to paralytic dislocation. She received bilateral PENG block and femoral cutaneous nerve block - a simple technique that covers all the nerves involved in the sensory innervation of the joint capsule without the need for multiple injections.  相似文献   
46.
We describe a case of undiagnosed heart block which was detected during the postpartum surgical repair of a vaginal tear, and the subsequent investigations that confirmed diagnosis of atrio-ventricular heart block.  相似文献   
47.
目的探讨腮腺切除术中应用沿面神经总干顺行解剖面神经的治疗效果及安全性。方法选取我院2016年2月至2019年3月收治的60例择期行腮腺切除术的患者,随机分为观察组与对照组各30例。对照组沿面神经总干逆行解剖面神经,观察组沿面神经总干顺行解剖面神经,观察两组患者术后1个月面神经功能及术后并发症发生情况。结果术后1个月,两组患者的面神经功能分级比较无统计学差异(P>0.05);观察组的术后并发症发生率为10.00%,明显低于对照组的33.33%(P <0.05)。结论临床行腮腺切除术中,沿面神经总干顺行解剖面神经可降低术后并发症发生率,值得推广。  相似文献   
48.
This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics.  相似文献   
49.
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号