全文获取类型
收费全文 | 13339篇 |
免费 | 1334篇 |
国内免费 | 934篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 157篇 |
妇产科学 | 99篇 |
基础医学 | 1528篇 |
口腔科学 | 199篇 |
临床医学 | 1645篇 |
内科学 | 1841篇 |
皮肤病学 | 155篇 |
神经病学 | 647篇 |
特种医学 | 454篇 |
外国民族医学 | 7篇 |
外科学 | 1386篇 |
综合类 | 2725篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 945篇 |
眼科学 | 260篇 |
药学 | 1501篇 |
9篇 | |
中国医学 | 880篇 |
肿瘤学 | 1088篇 |
出版年
2024年 | 62篇 |
2023年 | 210篇 |
2022年 | 544篇 |
2021年 | 647篇 |
2020年 | 480篇 |
2019年 | 496篇 |
2018年 | 475篇 |
2017年 | 407篇 |
2016年 | 393篇 |
2015年 | 534篇 |
2014年 | 708篇 |
2013年 | 685篇 |
2012年 | 845篇 |
2011年 | 935篇 |
2010年 | 647篇 |
2009年 | 491篇 |
2008年 | 546篇 |
2007年 | 636篇 |
2006年 | 648篇 |
2005年 | 593篇 |
2004年 | 543篇 |
2003年 | 712篇 |
2002年 | 669篇 |
2001年 | 552篇 |
2000年 | 393篇 |
1999年 | 359篇 |
1998年 | 185篇 |
1997年 | 190篇 |
1996年 | 150篇 |
1995年 | 139篇 |
1994年 | 124篇 |
1993年 | 93篇 |
1992年 | 86篇 |
1991年 | 85篇 |
1990年 | 71篇 |
1989年 | 59篇 |
1988年 | 53篇 |
1987年 | 45篇 |
1986年 | 42篇 |
1985年 | 24篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1968年 | 1篇 |
1966年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
目的 探讨脑硬死患者急性期血小板膜P -选择素 (CD6 2p)的表达及其与临床神经功能缺损程度的关系。方法 用流式细胞术测定 41例急性期脑梗死患者血小板膜CD6 2 p的表达。 结果 轻、中、重型脑梗死患者CD6 2 p的表达分别为 (1.38± 0 .2 9) %、(3.15± 1.5 8) %、(10 .46± 5 .0 7) % ,与正常对照组 (1.5 6± 0 .17) %比 ,轻型脑梗死患者CD6 2p的表达无显著性差异 (P >0 .0 5 ) ,中、重型脑梗死患者CD6 2 p的表达显著升高 (P <0 .0 5和0 .0 1)。结论 脑梗死患者急性期血小板膜CD6 2 p的表达与临床神经功能缺损程度有关。 相似文献
32.
包玉莲 《菏泽医学专科学校学报》2000,12(2):84-85
目的静脉输液拔针后,按压血管多长时间较为合适,目前尚无定论。旨在探讨按压血管的最佳时间,以便最大限度地减少皮下瘀血,减轻病人痛苦,保护静脉血管。方法对200例静脉输液病人拔针后不同按压血管时间的效果进行了观察,并根据统计处理结果进行分析、比较。结果拔针后4min左右较为合适,能够有效地防止瘀血,时间过长,多数病人难以坚持;过短则皮下瘀血率高。结论这种做法,克服了过去静脉输液拔针后,按压血管时间随意性较大的缺陷,应大力推广。 相似文献
33.
Objective: To observe the effects of Xin’an capsule (XAC) on experimental ventricular arrhythmia (EVA) in animals and to explore the possible mechanism.Methods: Three types of animal arrhythmic model (ventricular arrythmia in guinea pigs induced by Ouabin, in rats caused by reperfusion after ligation of descending anterior branch of coronary artery and by CaCl2) were used to study the effects of XAC on ventricular arrhythmia (VA).Results: After XAC treatment, the dosage of Ouabin needed for inducing ventricular premature beat (VPB), ventricular tachycardia (VT) and ventricular fibrillation (VF) increased in guinea pigs. The sustaining time of reperfusion induced VT and total occurrence of ventricular arrhythmias decreased. XAC also showed an effect in increasing CaCl2 dosage needed to cause VA, and decreased the occurrence of VF and death in rats 相似文献
34.
BACKGROUND: This experimental study sought to determine whether heparin-bonding of intraaortic balloons (IAB) would decrease the incidence of arterial thrombosis in the absence of systemic heparinization. METHODS: In 25 adult pigs, a 9F, 40-mL IAB was inserted into the femoral artery and positioned just below the takeoff of the left subclavian artery for 9 hours. Five animals received systemic heparin, 10 animals had no heparin, and another 10 animals received no heparin but the IAB was heparin-bonded (Duraflo II). Thrombus formation was assessed using a numerical scoring system (0 = no thrombosis to 3 = thrombus >5 cm or evidence of luminal compromise). RESULTS: Animals receiving heparin and heparin-bonded IAB had no thrombus formation around the IAB (mean +/- SE; 0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005), at the insertion site (0 +/- 0.00 heparin versus 1.55 +/- 0.29 no heparin versus 0 +/- 0.0 heparin-bonded; p < 0.005), and in the distal femoral artery (0 +/- 0.00 heparin versus 2.00 +/- 0.23 no heparin versus 0 +/- 0.00 heparin-bonded; p < 0.005). CONCLUSIONS: Heparin-bonding of the IAB significantly decreases thrombus formation in the absence of systemic heparinization. 相似文献
35.
Lazar HL Bao Y Lancaster D Shapira OM Aldea GS Shemin RJ 《The Annals of thoracic surgery》1999,68(5):1644-1647
BACKGROUND: This study was undertaken to determine the impact of the use and availability of coronary stents on outcomes in patients requiring emergent coronary artery bypass graft (CABG) surgery following a failed percutaneous transluminal coronary angioplasty (PTCA). METHODS: Patients were divided into two groups based on the year of their CABG for a failed PTCA and the availability of stents: group 1, 1992 to 1994, stents not available (n = 34); and group 2, 1995 to 1997, stents available (n = 26). RESULTS: CABG patients in the group where stents were not available were more likely to have had an abrupt coronary occlusion (26 of 34 versus 3 of 26; p < 0.0001) and less likely to have had a dissection (8 of 34 versus 23 of 26; p < 0.0001) as their indication for emergent CABG. Patients in the stent era had a lower incidence of perioperative myocardial infarction (5 of 26 versus 17 of 34; p < 0.01) and a decreased mortality rate (0 of 26 versus 6 of 34; p < 0.03). In the 9 patients where stents were employed, patency of the lumen was restored in 8 patients and there was only 1 myocardial infarction. CONCLUSIONS: Stents have had a favorable impact on patients requiring an emergent CABG following a failed PTCA. 相似文献
36.
Regulation of the angiotensin type-1 receptor by antisense oligonucleotides occurs through an RNase H-type mechanism 总被引:6,自引:0,他引:6
Multiple, diverse sites in the coding region of the angiotensin type-1 receptor mRNA were targeted with 2'-deoxyribonucleotide antisense oligonucleotides (ONs). The uptake of 1 microM concentration of these ONs into Chinese hamster ovary cells was facilitated by the use of cationic liposomes. The antisense sequences reduced binding of 125I-angiotensin II by 57-73%, while mismatch ONs and reverse sequence ONs produced little reduction in receptor binding. These reductions in AT1 receptor binding were accompanied by comparable decreases in AT1 receptor mRNA levels. Furthermore, mRNA cleavage fragments corresponding in size to 3'-cleavage fragments were observed with two of the antisense ONs, consistent with the involvement of an RNase H-type enzyme. When 2'-methoxyribonucleotide analogs of these same sequences were tested, AT1 receptor mRNA levels were unchanged even though small reductions in AngII binding were observed. Antisense effects seen with these 2'-methoxyribonucleotide sequences may have arisen through a translational arrest mechanism. Direct comparisons between 2'-deoxyribonucleotide analogs and their 2'-methoxyribonucleotide counterparts show that antisense effects are significantly larger when they are mediated through an RNase H-type mechanism. 2'-methoxyribonucleotide sequences were most effective when they were directed against the translation initiation codon. 相似文献
37.
Glutathione (GSH) is known to play an important role in regulating oxidative damage to cells. The present study was initiated to examine the effect of exogenous GSH on oxidative injury in a retinal Müller cell line and to characterize GSH transport in these cells. Rat Müller cells (rMC-1) were incubated with varying concentrations of t-butylhydroperoxide (t-BHP) to induce oxidative stress, and cell viability was measured after addition of GSH. In other studies, kinetics of GSH uptake and Na+-dependency were examined by incubating cells with35S-GSH in Na+-containing and Na+-free buffers. GSH uptake was studied with GSH at concentrations varying from 0. 05-10 m m in NaCl buffer. In the presence of sodium, extracellular GSH provided protection against t-BHP-induced oxidant injury to rMC-1 cells; in contrast, the amino acid precursors of GSH did not have any effect on cell viability. GSH was taken up by rMC-1 cells in a concentration- and sodium-dependent manner. Kinetic studies revealed both a high affinity (Km approximately 0.31 m m) and low affinity Km( approximately 4.2 m m) component. Furthermore, GSH depletion had no significant effect on the rate of GSH uptake. The results show that physiological concentrations of GSH can protect Müller cells from oxidative injury. Both Na+-dependent and Na+-independent transport systems for GSH exist in Müller cells, and the Na+-dependent GSH transporter may be involved in the protective role of GSH. 相似文献
38.
The author used smear from Stensen's duct aspiration to observe exfoliated cytology in order to help diagnosis of early mumps.According to the smears from 100 cases of mumps and other 50 cases of bacteria parotitis and/or normal parotid as contro,the author revealed that if there are a lot of ductal epithelial cells,monocytes and polynuclear cells,monocytes and polynuclear phagocytes at same time,it could give diagnosis "Mumps" to that patient.In control group,it is unable to observe those three kind cells at same time.The author also discussed the mechanism of how would these three kind cells appear in mumps in accordance with references. 相似文献
39.
目的:评价激光虹膜切除治疗闭角型青光眼临床疗效。方法:应用Nd:YAG激光于上方或下方作周边虹膜切除。结果:107例122眼闭角型青光眼术后经过2—106月随访观察,成功115眼,失败7眼。结论:激光虹膜切除术治疗闭角型青光眼安全、有效。 相似文献
40.
克罗米酚与HCG促排卵作用的临床观察 总被引:4,自引:0,他引:4
目的 认识克罗米酚 (CC)促排卵的缺陷 ,评价人绒毛膜促性腺激素 (HCG)的辅助作用。方法 具有正常月经周期的妇女 95例 ,对照组 39例 ;单独使用CC组 30例 ;CC +HCG组 2 6例。观察三组受试者排卵率、子宫内膜厚度及回声类型、排卵日 (LH +0 )及种植窗期 (LH +7)激素水平。结果 CC使子宫内膜变薄 ,回声类型改变 ;CC使黄素化不破裂卵泡综合征 (LUFS)的发生率 (36 6 7% )增加 ,与对照组 (5 13% )比较P <0 0 5 ;CC使种植窗期E2 异常增高 (对照组 115 0 0pg ml,CC组 2 89 5 0pg ml,P <0 0 5 ) ;E2 、P水平与内膜厚度无明显相关性 ,且不能预测LUFS的发生 ;HCG有望降低LUFS的发生率。结论 CC可能使子宫内膜厚度、回声类型、血清激素环境偏离种植所需的理想状态 ;并增加LUFS的发生率 ,HCG的使用有望纠正CC在促排卵过程中的这一缺陷 相似文献