全文获取类型
收费全文 | 12840篇 |
免费 | 900篇 |
国内免费 | 265篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 181篇 |
妇产科学 | 259篇 |
基础医学 | 705篇 |
口腔科学 | 116篇 |
临床医学 | 2207篇 |
内科学 | 946篇 |
皮肤病学 | 62篇 |
神经病学 | 604篇 |
特种医学 | 180篇 |
外科学 | 1758篇 |
综合类 | 2627篇 |
预防医学 | 1273篇 |
眼科学 | 73篇 |
药学 | 1789篇 |
42篇 | |
中国医学 | 706篇 |
肿瘤学 | 381篇 |
出版年
2024年 | 39篇 |
2023年 | 212篇 |
2022年 | 421篇 |
2021年 | 555篇 |
2020年 | 640篇 |
2019年 | 426篇 |
2018年 | 391篇 |
2017年 | 458篇 |
2016年 | 477篇 |
2015年 | 503篇 |
2014年 | 1003篇 |
2013年 | 925篇 |
2012年 | 1116篇 |
2011年 | 1063篇 |
2010年 | 853篇 |
2009年 | 669篇 |
2008年 | 559篇 |
2007年 | 556篇 |
2006年 | 487篇 |
2005年 | 401篇 |
2004年 | 290篇 |
2003年 | 278篇 |
2002年 | 240篇 |
2001年 | 170篇 |
2000年 | 135篇 |
1999年 | 137篇 |
1998年 | 95篇 |
1997年 | 72篇 |
1996年 | 73篇 |
1995年 | 66篇 |
1994年 | 71篇 |
1993年 | 44篇 |
1992年 | 41篇 |
1991年 | 52篇 |
1990年 | 46篇 |
1989年 | 45篇 |
1988年 | 41篇 |
1987年 | 31篇 |
1986年 | 48篇 |
1985年 | 40篇 |
1984年 | 39篇 |
1983年 | 14篇 |
1982年 | 21篇 |
1981年 | 33篇 |
1980年 | 17篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 17篇 |
1976年 | 23篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Prenatal Stress Increases the Hypothalamo-Pituitary-Adrenal Axis Response in Young and Adult Rats 总被引:11,自引:0,他引:11
Chantal Henry Mohamed Kabbaj Hervé Simon Michel Le Moal Stefania Maccari 《Journal of neuroendocrinology》1994,6(3):341-345
Prenatal stress is considered as an early epigenetic factor able to induce long-lasting alterations in brain structures and functions. It is still unclear whether prenatal stress can induce long-lasting modifications in the hypothalamo-pituitary-adrenal axis. To test this possibility the effects of restraint stress in pregnant rats during the third week of gestation were investigated in the functional properties of the hypothalamo-pituitary-adrenal axis and hippocampal type I and type II corticosteroid receptors in the male offspring at 3, 21 and 90 days of age. Plasma corticosterone was significantly elevated in prenatally-stressed rats at 3 and 21 days after exposure to novelty. At 90 days of age, prenatally-stressed rats showed a longer duration of corticosterone secretion after exposure to novelty. No change was observed for type I and type II receptor densities 3 days after birth, but both receptor subtypes were decreased in the hippocampus of prenatally-stressed offspring at 21 and 90 days of life. These findings suggest that prenatal stress produces long term changes in the hypothalamo-pituitary-adrenal axis in the offspring. 相似文献
52.
J. J. HOORWEG J. A. RAUWERDA G. A. CROLL A. J. C. MACKAAY E. K. J. RISSE N. DE VRIES R. M. TIWARI 《Clinical otolaryngology》1994,19(6):496-501
The records of 28 patients who underwent free jejunal graft reconstruction after resection for cancer involving the pharynx were analysed. Seven patients had a T3 carcinoma, 15 patients T4 and six patients recurrence after laryngectomy. Ten patients had received radiotherapy in the past. Post-operatively, 15 patients (54%) had complications and two patients (7%) died. No significant difference was observed in the complication rate between the group that received radiotherapy in the past and those who did not. Nineteen patients received post-operative radiotherapy. Nine patients had no radiotherapy on the basis of complete resection or because of serious complications. For the whole group the 2-year recurrence free period and survival were 42% and 51% respectively. The postoperative radiotherapy group had a significantly better survival (73%) and recurrence free period (63%) than the group without post-operative radiotherapy (0%). Thus, post-operative radiotherapy seems indicated irrespective of resection margins. 相似文献
53.
ANDREW SHERWOOD SUSAN S. GIRDLER EDITH E. BRAGDON SHEILA G. WEST KIMBERLY A. BROWNLEY ALAN L. HINDERLITER KATHLEEN C. LIGHT 《Psychophysiology》1997,34(2):185-191
In this study we examined test-retest stability of cardiovascular stress responses over a decade of the life span. Participants were 55 male college undergraduates. 19 years of age at initial testing, and 29 years of age at follow-up testing Stressors were a foot cold pressor and an aversive reaction time task. Cardiovascular measures included systolic and diastolic blood pressure, heart rate, and preejection period. For cold pressor, the magnitude and pattern of cardiovascular responses remained unchanged at the 10-year follow-up. For the reaction time task, the characteristic cardiovascular response patterns was preserved but with significant attenuation of magnitude. The present findings are consistent with previous observations of temporal stability but over a substantially longer test-retest interval. The long-term stability of stress responses is discussed in the context of stress test methodology, behavioral response demands, and maturation of the physiological systems involved in cardiovascular response expression. 相似文献
54.
从宫颈癌、大肠癌等病种的自然史抽象出一个具有时变伴随变量的潜隐期二阶段模型。潜隐期以正常状态为起点,疾病为终点;其前阶段可逆,后阶段不可逆;状态间转移速率因病人状况而异。用Markov过程描述并求解此模型,进而给出参数估计和假设检验方法。利用此模型基于江西省靖安县12年6轮宫颈癌筛查资料进行了自然史研究,并讨论了应用前景。 相似文献
55.
原位心脏移植30例临床分析 总被引:7,自引:0,他引:7
目的对30例心脏移植进行分析总结。方法30例患者中,24例的原发病为扩张型心肌病,4例为终末期瓣膜性心肌病,1例为终末期缺血性心肌病,1例为病毒性心肌炎行双心室辅助术后1个月。均在体外循环下行原位心脏移植术,3例采用标准心脏移植术式,27例采用双腔静脉吻合心脏移植术式,体外循环时间(75±24)min,主动脉阻断时间(72±8)min。术后采用环孢素A、霉酚酸酯和泼尼松预防排斥反应,根据血环孢素A的浓度调整CsA的用量。术后早期,每天行心肌内心电图及超声心动多普勒监测,以便早期发现急性排斥反应,必要时行心内膜心肌活检。结果30例患者中,术后死亡5例,3例死于低心排,1例死于感染所致的多器官功能衰竭,1例死于出血。术后并发症有低心排、心律失常、三尖瓣返流、右心衰竭、细菌和真菌感染、肾功能异常及血糖升高,上述并发症除导致死亡者外,其余经治疗好转;4例发生急性排斥反应,给予甲泼尼龙冲击治疗,并调整免疫抑制剂的用量后排斥反应逆转。结论术后并发症的预防和及时正确的处理,是心脏移植成功的关键,尤其是对感染、急性排斥反应、右心功能不全及肾功能异常的预防和处理。 相似文献
56.
左旋门冬氨酸鸟氨酸在急性重症胆管炎围手术期中的应用研究 总被引:2,自引:0,他引:2
目的评估左旋门冬氨酸鸟氨酸在急性重症型胆管炎(ACST)患者围手术期的应用价值。方法将69例ACST患者随机分两组:A组为实验组(应用左旋门冬氨酸鸟氨酸组),共36例;B组为对照组(常规治疗组),共33例。术后第1、5、7天分别检测患者的白细胞计数、血小板计数、ALT、AST、TBIL以及监测肾功能BUN、Cr等指标。结果A组患者上述指标改善明显优于B组,两组数据差异有统计学意义(P<0.05)。结论ACST患者围手术期应用左旋门冬氨酸鸟氨酸可加快患者术后恢复,减少术后并发症及降低病死率。 相似文献
57.
58.
目的探讨急非淋白血病完全缓解后巩固治疗与缓解期的关系。方法对30例坚持与未坚持完全缓解后巩固化疗的急非淋患者(每组15例)进行对照研究。比较两组患者的完全缓解期。结果两组患者入院时情况、治疗及达完全缓解时间经统计学处理无明显差异(P>0.05);而坚持巩固化疗组平均持续完全缓解期(19.8mo)明显长于对照组(8.4mo),统计学具有显著差异(P<0.01)。结论急非淋白血病达完全缓解后,坚持骨髓抑制性治疗对延长完全缓解期以达长期生存目的具有重要意义。 相似文献
59.
60.
A9 and A10 units identified as dopaminergic were recorded with extracellular micropipettes. The units were antidromically activated by electrical stimulation at the level of the preoptic area. The absolute refractory periods ranged from 1.2 to 2.5 ms. During the 2–8 ms of the relative refractory period, conduction was slower than normal by up to 1.5 ms. The time constant, C, of the strength-duration curve ranged from 0.4 to 0.6 ms. The current (I)-distance (D) relationship, tested by moving the stimulating electrode past the axon, was approximately parabolic (I = K D exp 2), with the constant of the equation, K, ranging from 900 to 2000 μA/mm exp 2, for 0.5 ms pulses. This relationship allows calculation of the radius of the field of dopamine axon excitation at any current. These high K values show that axons of dopamine cells cannot be activated unless high current densities are derivered, even when electrodes are placed near the axons. These data allow determination of the extent to which dopamine axons can be the directly activated substrates for behaviors, such as self-stimulation and circling, which are evoked by electrical stimulation of the medial forebrain bundle or internal capsule. 相似文献