全文获取类型
收费全文 | 5632篇 |
免费 | 488篇 |
国内免费 | 163篇 |
专业分类
儿科学 | 107篇 |
妇产科学 | 20篇 |
基础医学 | 816篇 |
口腔科学 | 15篇 |
临床医学 | 1141篇 |
内科学 | 453篇 |
皮肤病学 | 39篇 |
神经病学 | 510篇 |
特种医学 | 337篇 |
外国民族医学 | 2篇 |
外科学 | 1093篇 |
综合类 | 707篇 |
预防医学 | 224篇 |
眼科学 | 5篇 |
药学 | 313篇 |
13篇 | |
中国医学 | 275篇 |
肿瘤学 | 213篇 |
出版年
2024年 | 37篇 |
2023年 | 131篇 |
2022年 | 287篇 |
2021年 | 334篇 |
2020年 | 319篇 |
2019年 | 268篇 |
2018年 | 241篇 |
2017年 | 228篇 |
2016年 | 255篇 |
2015年 | 221篇 |
2014年 | 453篇 |
2013年 | 477篇 |
2012年 | 316篇 |
2011年 | 335篇 |
2010年 | 247篇 |
2009年 | 227篇 |
2008年 | 227篇 |
2007年 | 205篇 |
2006年 | 180篇 |
2005年 | 163篇 |
2004年 | 135篇 |
2003年 | 118篇 |
2002年 | 86篇 |
2001年 | 95篇 |
2000年 | 95篇 |
1999年 | 65篇 |
1998年 | 48篇 |
1997年 | 55篇 |
1996年 | 43篇 |
1995年 | 51篇 |
1994年 | 31篇 |
1993年 | 41篇 |
1992年 | 43篇 |
1991年 | 22篇 |
1990年 | 26篇 |
1989年 | 13篇 |
1988年 | 24篇 |
1987年 | 14篇 |
1986年 | 16篇 |
1985年 | 15篇 |
1984年 | 23篇 |
1983年 | 6篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有6283条查询结果,搜索用时 13 毫秒
21.
肢体负压对周围动脉闭塞性病变犬皮肤SP免疫反应阳性神经纤维影响 总被引:3,自引:0,他引:3
目的 观察肢体负压对周围动脉闭塞性病变犬皮肤中 SP免疫反应阳性神经纤维的影响 .方法 犬 17只 ,随机分治疗组 10只、非治疗组 5只和正常对照组 2只 ,治疗组和非治疗组均将动物制作左后肢缺血模型 ,治疗组在模型制作后 14d,开始行患肢负压治疗 10 d(15 min·次 - 1 ) ;非治疗组不做负压治疗 ;正常对照组不行缺血模型制作及负压治疗 . 3组均行左后肢趾皮肤免疫组化染色 ,检测 SP免疫反应阳性纤维 .结果 非治疗组皮肤中 SP免疫反应阳性神经纤维均较正常对照组明显增多 (P<0 .0 1) ,治疗组较非治疗组减少(P<0 .0 1) ,但仍较正常对照组增多 .结论 肢体负压疗法可促进皮肤感觉神经纤维中 SP的释放 相似文献
22.
反复下体负压暴露对心脏泵血功能的影响 总被引:1,自引:0,他引:1
目的 探讨反复下体负压暴露对心脏泵血功能的影响及其与下体负压耐力的关系 .方法 2 7名男性健康被试者随机分成 3组 ,分别进行 - 5 .33 k Pa 8min(A组 )、- 6 .6 7k Pa4min(B组 )、- 6 .6 7k Pa8m in(C组 )的下体负压锻炼 ,1次· d- 1 ,连续 8d,记录心率及血压 .锻炼前、后测量平卧位心脏泵血功能 .结果 A组锻炼前后心脏功能各项指标无显著变化 (P>0 .0 5 ) ,B组锻炼后左室射血期 (L VET)、每搏输出量 (SV)、心输出量 (CO)、心指数 (CI)、血管顺应性 (C)分别为 :(2 97± 14) ms,(113± 37) m L,(7.3± 2 .3) L· min- 1 ,(4.2± 1.4) L·min- 1·m- 2 ,(2 .7± 1.0 ) m L·Pa- 1 ,较锻炼前显著增加 (P<0 .0 5 ) .而总外周阻力 (TPR)为 (7.6± 2 .9)L· Pa- 1·cm- 5,较锻炼前显著降低 (P<0 .0 5 ) .C组锻炼后较锻炼前上述指标变化趋势与 B组相同 ,但未达显著水平 .结论 - 6 .6 7k Pa反复下体负压暴露可改善心脏泵血功能 ,其可能通过相对提高心水平动脉血压而提高下体负压耐力 相似文献
23.
About 30% of patients who have a Roux-en-Y gastrojejunostomy after gastrectomy suffer from abdominal pain, nausea, vomiting
of food and bloating made worse by eating. This syndrome, called the Roux stasis syndrome, is caused, in part, by a motility
disorder of the Roux limb. Transection of the jejunum during the construction of the limb separates the limb from the natural
small intestinal pacemaker located in the duodenum. Ectopic pacemakers then appear in the limb and trigger retrograde contractions
in its proximal portion. These contractions slow transit through the limb and result in Roux stasis. Current nonsurgical treatment
of the syndrome includes the use of prokinetic agents and intestinal pacing, neither of which has demonstrated long-term benefits.
A near-total gastrectomy may speed upper gastrointestinal transit somewhat, but stasis in the Roux limb often persists. Our
current approach aims at preventing the syndrome by the use of an ‘uncut’ Roux limb, an operation which preserves myoneural
continuity between the duodenal pacemaker and the Roux limb and so prevents the appearance of ectopic pacemakers and stasis
in the limb. 相似文献
24.
The purpose of this study was to examine whether cardiorespiratory responses to combined rhythmic exercise (60 contractions · min–1) was affected by different combinations of upper and lower limb exercise in seven healthy women. Six different rhythmic exercises were compared: 6-min rhythmic handgrip at 10% of isometric maximal voluntary contraction (MVC) (H10); 6-min rhythmic plantar flexion at 10% MVC (P10); exhausting rhythmic handgrip at 50% MVC (H50); exhausting rhythmic plantar flexion at 50% MVC (P50); H50 was added to P10 (P1OH50); and P50 was added to H10 (H10P50). Exercise duration, after handgrip was combined with plantar flexion (P10H50), was shorter than that of H50, although the exercise duration of HIOP50 was not significantly different from P50. No significant difference was found between the difference from rest in oxygen uptake (
O2) during H10P50 and the sum of
O2 during H10 and P50. Also, the differences from rest in forearm blood flow ( FBF) and calf blood flow ( CBF) during H10P50 were not significantly different from FBF in H10 and from CBF in P50. In contrast,
O2 in P10H50 was lower than the sum of
O2 in P10 and H50 (P < 0.05), and J FBF in P10H50 was lower than that in H50 (P < 0.05) , while CBF was not significantly different between P1OH50 and P10. The changes in heart rate from rest (d HR) during the combined exercises were lower than the sums of HR in the corresponding single exercises (P < 0.05). These results demonstrated an inhibitory summation of several cardiorespiratory responses to combined exercise resulting in a reduction in exercise performance which would seem to occur easily when upperlimb exercise is added to lower limb exercise. 相似文献
25.
By intra-adnexal injection of glucose in the rabbit embryo, we were able to stimulate all the anomalies associated with "Amniotic Disease". Since we were even able to obtain amniotic bands, this study provides an excellent experimental model of this disease. Resulting lesions occur early in development, corresponding to the first trimester of human gestation. All of the anomalies can ultimately be explained by the destruction of the most superficial cells: epiblastic cells of the embryo and the amnion, subjacent mesenchyme, and endothelial cells. The subsequent lack of interaction between these cells and the importance of the anatomical localizations of resulting hematomas can lead to the pathogenetic approach to this disease. In light of the present study, the disease appears to be caused by an external factor within the amniotic fluid. The exact nature of the destructive agent(s) remains a mystery in man. 相似文献
26.
A. A. Gehani P. Thorley K. Sheard S. Ashley S. G. Brook M. R. Rees 《European journal of nuclear medicine and molecular imaging》1992,19(1):6-13
In a prospective study, a radionuclide technique was used to evaluate the limb blood flow (LBF) changes in 30 patients undergoing dynamic (n=15) or balloon (n=15) angioplasty for arterial occlusions or stenoses, respectively. The results were compared with Doppler Ankle Brachial Index (DABI) and treadmill exercise tests. Whilst LBF values (ml of blood flow per 100 ml of limb volume per min) were significantly lower in limbs with arterial occlusion than stenosis (4.5±0.46 and 6.4±0.74, respectively; P<0.05), DABI provided no discrimination. Immediately after balloon angioplasty, there was a fall in DABI, from 0.60±0.05 to 0.47±0.04 (P<0.05), which rose 24 h later to 0.73±0.02 (P<0.01). Following dynamic angioplasty, DABI improved from 0.60±0.05 to 0.66±0.02 (P<0.05). At 3 weeks, the LBF improved from 4.6±0.66 to 11.1±0.53 (P<0.001) following dynamic angioplasty and from 6.2±0.68 to 8.53±0.81 (P<0.001) following balloon angioplasty. Normal LBF (> 10 ml/100 ml per min) was achieved in 80% of patients who underwent successful dynamic angioplasty but in only 36% of the balloon group (P<0.05, 2-test). Reproducibility of repeated LBF measurements in control limbs was superior to that of DABI. This was indicated by a lower coefficient of variation, 13.8% compared with 25.2%, and a higher correlation coefficient, r=0.79 compared with 0.27. Treadmill exercise tests were invalid or impossible in 30% of all occasions. There was a good correlation between the improvement in maximum walking distance on the treadmill and that in LBF (r=0.84, P<0.05). In conclusion, measurement of LBF using radionuclide technique is a potentially valuable method for the assessment of patients undergoing percutaneous angioplasty. LBF results are reproducible and correlate well with the improvement in walking ability, which cannot always be assessed objectively.
Offprint requests to: A.A. Gehani 相似文献
27.
28.
目的:探索肢体缺血预处理对肝脏缺血再灌注损伤的影响.方法:32只新西兰兔用四氯化碳颈背部皮下注射法建立肝硬变模型.将成功建模的28只肝硬变兔分为假手术组(S组)、缺血再灌注组(IR组)、肝脏缺血预处理组(IPC组)、肢体缺血预处理组(LIPC组)各7只.实验前12h禁食,自由饮水.检测模型试验前后肝脏生化酶(ALT、AST)指标及肝脏组织中ATP含量水平.结果:LIPC组ALT、AST指标与S组、IR组比较差异均有显著统计学意义(P<0.01),与IPC组比较无统计学意义(P>0.05);LIPC组ATP指标水平与S组、IR组比较差异均有显著统计学意义(P<0.01),与IPC组比较无统计学意义(P>0.05).结论:肢体缺血预处理对肝脏缺血再灌注损伤具有保护作用. 相似文献
29.
Earlier in vitro studies of the compounds marked as GT27, GT28, GT29 and BM128 revealed their inhibitory action towards murine γ-aminobutyric acid (GABA) transporters (mGAT1-mGAT4). In the present paper, the pharmacological activity of four γ-hydroxybutyric acid (GHB) amide derivatives was investigated. The following procedures were involved: locomotor activity, hot plate and electroconvulsive threshold tests. The compounds' influence on motor coordination was evaluated in the chimney test, as well. Intraperitoneal (i.p.) administration of the GHB derivatives decreased animals' locomotor activity (ED(50) values ranged between 23.79 and 26.37 mg/kg). At a dose of 25 mg/kg (i.p.) the compounds prolonged the nociceptive reaction time latency in the hot plate assay to various degree and GT28 and GT29 were the most potent ones in this respect. Their analgesic efficacy was particularly pronounced 30 min after their administration [percent of maximal possible effect (%MPE) = 16.93 and 22.72, respectively]. The investigated GHB derivatives, except for GT29 at 100 mg/kg, increased the electroconvulsive threshold by approximately 4-11 mA as compared to the vehicle-treated mice. In the chimney test they impaired the animals' motor coordination to various degree. We suggest further investigations of the compounds to estimate their biological activity. 相似文献
30.
Tadayoshi Nonoyama Hiroko Shigemi Masafumi Kubota Akihiko Matsumine Kenji Shigemi Tamotsu Ishizuka 《Medicine》2022,101(31)
Critically ill patients in the intensive care unit (ICU) develop muscle atrophy and decreased physical function. Though neuromuscular electrical stimulation (NMES) therapy has been shown to be effective in preventing this, but its effect on older patients is unknown.To examine the course of critically ill older patients treated with NMES in the ICU and to define the impact of its use.A retrospective cohort study was conducted using older ICU patients (≥65 years) categorized into a control group (n = 20) and an NMES group (n = 22). For subgroup analysis, each group was further classified into pre-old age (65–74 years) and old age (≥75 years).The control group showed significant decrease in muscle thickness during ICU and hospital stay. The NMES group showed lower reduction in muscle thickness and showed decrease in muscle echo intensity during hospital stay, compared to the control group. NMES inhibited decrease in muscle thickness in the pre-old age group versus the old age group. The decreasing effect of NMES on echo intensity during hospital stay manifested only in the pre-old age group. We did not find much difference in physical functioning between the NMES and control groups.Lower limb muscle atrophy reduces in critically ill older patients (≥65 years) with NMES and is pronounced in patients aged < 75 years. The impact of NMES on the physical functioning of older patients in ICU needs to be further investigated. 相似文献