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   63601篇
  免费   5746篇
  国内免费   3503篇
耳鼻咽喉   604篇
儿科学   1004篇
妇产科学   791篇
基础医学   6632篇
口腔科学   1167篇
临床医学   6884篇
内科学   9449篇
皮肤病学   1077篇
神经病学   3204篇
特种医学   2629篇
外国民族医学   14篇
外科学   7906篇
综合类   10641篇
现状与发展   13篇
一般理论   3篇
预防医学   4634篇
眼科学   1242篇
药学   6404篇
  50篇
中国医学   3863篇
肿瘤学   4639篇
  2024年   162篇
  2023年   679篇
  2022年   1601篇
  2021年   2344篇
  2020年   1840篇
  2019年   1624篇
  2018年   1850篇
  2017年   1823篇
  2016年   1767篇
  2015年   2496篇
  2014年   3225篇
  2013年   3509篇
  2012年   5013篇
  2011年   5445篇
  2010年   4080篇
  2009年   3530篇
  2008年   4229篇
  2007年   4033篇
  2006年   3811篇
  2005年   3340篇
  2004年   2934篇
  2003年   2752篇
  2002年   2494篇
  2001年   1784篇
  2000年   1404篇
  1999年   985篇
  1998年   542篇
  1997年   479篇
  1996年   384篇
  1995年   334篇
  1994年   297篇
  1993年   182篇
  1992年   232篇
  1991年   238篇
  1990年   197篇
  1989年   141篇
  1988年   121篇
  1987年   117篇
  1986年   103篇
  1985年   95篇
  1984年   60篇
  1983年   38篇
  1982年   31篇
  1980年   37篇
  1979年   40篇
  1977年   39篇
  1976年   36篇
  1975年   33篇
  1974年   36篇
  1972年   30篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished.  相似文献   
22.
23.
目的:总结Ⅰ期在第2足趾游离移植再造拇(手)指中行趾甲延长的临床应用经验.方法:采用趾甲延长方法对9例(男7,女2例)第2足趾移植再造拇(手)指的患者进行了趾甲延长术,其中拇指8例,食指1例.年龄18~46岁,平均25岁.在再造指距甲根皮缘5 mm处,去除1块矩形皮肤,勿损伤皮下血管网.其高度2 mm,宽度与趾甲相等,将U形皮瓣向近端柔和推剥并缝合.结果:1例术后供区发生表浅感染,经换敷料逐渐愈合.再造的拇(手)指全部成活,可延长趾甲2~3 mm,改善了再造拇(手)指的外形,无指甲生长畸形发生.随访7个月~2年(平均13个月),趾甲外形较好.结论:在第2足趾游离移植再造拇(手)指中应用Ⅰ期趾甲延长术,使趾甲从短小向纵向延长,缩小手指甲与足趾甲之间差异,能改善再造拇(手)指甲外形,且不影响再造指的活动功能,是一种简单有效的手术方法.  相似文献   
24.
Objective To observe the effect of intrathecal clonidine plus morphine on expression of protein kinase A (PKA) catalytic subunit in the spinal dorsal horn in a rat model of incisional pain. Methods Eighty male Sprague-Dawley rats were divided randomly into five groups: sham group, control group, pre-incisional morphine 2.5 μg group, pro-incisional clonidine 5 μg group and preincisional morphine 2.5 μg plus clonidine 5 lag group (n=16). lntrathecal catheter and the model of incisional pain were pro-duced according to Yaksh and Brennan's described method respectively. Changes of pain behavior were assessed by mechanical with-drawal threshold (MWT) and thermal withdrawal latency(TWL). The expressions of PKA catalytic subunit in the spinal dorsal horn were assessed by immunohistochemical method and western blotting analysis. Results Compared with sham group, MWT and TWL in control group were decreased significantly at 2 h after incision (P<0.01) and the number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn were increased significantly in control group (P<0.01). Compared with control group, MWT and TWL in pre-incision morphine 2 μg plus clonidine 5 lag group were increased significantly at 2 h after incision (P<0.01) and the number of positive cells and protein expression of PKA catalytic subunit in the spinal dorsal horn were decreased significantly in pre-incision morphine 2 μg plus clonidine 5 μg group (P<0.01). However, MWT, TWL and the number of positive cells and pro-tein expression of PKA catalytic subunit in the spinal dorsal horn changed with no statistical significance in pre-incisional morphine 2.5 μg group and pre-incisional clonidine 5 μg group compared with control group. Conclusion lntrathecal clonidine significantly enhances the antinociceptive effect of intrathecal morphine in a rat model of incisional pain, which might be associated with inhibi-tion of the increased expression of PKA catalytic subunit in spinal cord.  相似文献   
25.
改良开放性手术治疗巨大良性前列腺增生症   总被引:2,自引:0,他引:2  
目的探讨巨大良性前列腺增生症的开放性手术治疗方法及效果。方法回顾分析16例巨大良性前列腺增生症,年龄61~88岁,平均74岁。作耻骨上经膀胱前列腺切除术。结果手术均成功;手术时间35~65min,出血量100~200mL,术后前列腺重量为200~520g,平均215g;膀胱冲洗2~3d,拔导尿管5~7d;术后3d再出血1例,经DSA同侧髂内血管栓塞止血成功,排尿困难1例,短期尿失禁1例,其余患者术后均排尿通畅,控尿良好。结论开放性手术治疗巨大良性前列腺增生症,其梗阻解除彻底,是一种合理的治疗方法。恰当的手术方法是提高疗效及降低并发症的关键。  相似文献   
26.
The purpose of this paper is to describe the design and development of the Clinical Practice Library of Medicine (CPLM). CPLM is an investigational project aimed at providing health care practitioners with critical in-depth information similar to that obtained from a medical reference library or consultant. When used in conjunction with the physician's knowledge, CPLM can provide valuable diagnostic prompting information to assist in rapidly reaching a suitable diagnosis for timely administration of appropriate treatment. This system may also be used to assist paramedical professionals working in remote areas where other expert medical assistance may not be available.  相似文献   
27.
28.
Aim: To examine the survival benefit of liver and lung resection for colorectal metastasis and the potential prognostic factors that affect patient survival. Methods: All patients who had resection of lung or liver metastasis for colorectal metastasis in Queen Elizabeth Hospital, Hong Kong from 1995 to 2004 were retrospectively reviewed. The overall and disease‐free survival was analysed, in particularly between liver and lung metastasis. All factors that may have affected the survival were entered into Cox's proportional hazards regression model to identify significant variables associated with survival. Results: At 5 years, the overall survival of patients who had resection of lung and liver metastasis was 44% and 38%, respectively; the disease‐free survival was 26% and 24%, respectively. Overall and disease‐free survival of patients with resection of lung metastasis was comparable to those with resection of liver metastasis. The differentiations of primary tumour and time to metastasis were shown to be significant prognostic factors influencing overall survival. Those patients with systemic chemotherapy after resection of colorectal metastasis demonstrated a significantly higher probability of overall survival. Conclusion: Resection of lung and liver metastases from colorectal origin was safe and both procedures improved survival. The use of chemotherapy after resection of metastasis significantly improved the overall survival.  相似文献   
29.
Objective: Two major changes have occurred in inguinal hernia repair during the last two decades: (i) the use of tension‐free mesh repair; and (ii) the application of laparoscopic technique for repair. The aims of the present study were to study: (i) how inguinal hernia repair was carried out; and (ii) the outcome of inguinal hernia repair in Hospital Authority (HA) hospitals. Methodology: This was a retrospective analysis on 8311 elective inguinal hernia repairs performed in 16 HA hospitals from January 2001 to December 2003. The mean age was 63.9 ± 14.2 years, and the male to female ratio was 22.0 : 1.0. Among these, 869 (10.5%) repairs were performed with the laparoscopic approach and 7442 (89.5%) repairs with the open approach. The proportion of laparoscopic hernia repair increased from 8.7% to 12.6%. Results: For open repair, 39% of cases were carried out with regional anaesthesia, 32% with general anaesthesia and 29% with local anaesthesia (LA). Furthermore, mesh repair was used in 88% of the patients. For laparosocpic repair, 98.4% of cases were carried out under general anaesthesia, and all patients had mesh repair using the totally extraperitoneal approach. A significantly higher proportion of bilateral repair and recurrent hernia repair was performed with the laparoscopic approach (P = 0.000). For primary unilateral repair, there was no significant difference in the postoperative length of stay (LOS) and the total LOS between the laparoscopic and the open surgery groups. No difference in LOS was found in recurrent hernia repair between the two groups. With respect to bilateral repair, both the preoperative LOS (P = 0.036) and total LOS (P = 0.039) were shorter in the laparoscopic group. Furthermore, a significantly higher proportion of day‐surgery patients was observed in the laparoscopic group than the open surgery group (21.3%vs 16.9%, P = 0.001). Nevertheless, when only the results of 2003 were analyzed, the postoperative LOS (P = 0.000) and total LOS (P = 0.000) were significantly shorter in the laparoscopic group than the open surgery group. The LOS parameters were significantly shorter in the open surgery LA subgroup compared with the non‐LA subgroup (P = 0.000), and they were not different from those in the laparoscopic group. Conclusions: The open mesh repair is the predominant approach for inguinal hernia repair in HA hospitals. The originally described local anaesthetic approach was under utilized, although it resulted in good outcome. The use of laparoscopic hernia repair is increasing and a learning curve was recently observed with improved outcome.  相似文献   
30.
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