全文获取类型
收费全文 | 15814篇 |
免费 | 1176篇 |
国内免费 | 572篇 |
专业分类
耳鼻咽喉 | 72篇 |
儿科学 | 178篇 |
妇产科学 | 155篇 |
基础医学 | 813篇 |
口腔科学 | 601篇 |
临床医学 | 1503篇 |
内科学 | 2721篇 |
皮肤病学 | 395篇 |
神经病学 | 535篇 |
特种医学 | 661篇 |
外科学 | 1848篇 |
综合类 | 1627篇 |
现状与发展 | 1篇 |
预防医学 | 801篇 |
眼科学 | 152篇 |
药学 | 4063篇 |
5篇 | |
中国医学 | 192篇 |
肿瘤学 | 1239篇 |
出版年
2024年 | 20篇 |
2023年 | 199篇 |
2022年 | 362篇 |
2021年 | 557篇 |
2020年 | 535篇 |
2019年 | 556篇 |
2018年 | 558篇 |
2017年 | 533篇 |
2016年 | 608篇 |
2015年 | 635篇 |
2014年 | 899篇 |
2013年 | 1595篇 |
2012年 | 892篇 |
2011年 | 953篇 |
2010年 | 744篇 |
2009年 | 718篇 |
2008年 | 727篇 |
2007年 | 723篇 |
2006年 | 594篇 |
2005年 | 605篇 |
2004年 | 489篇 |
2003年 | 463篇 |
2002年 | 386篇 |
2001年 | 320篇 |
2000年 | 283篇 |
1999年 | 221篇 |
1998年 | 203篇 |
1997年 | 228篇 |
1996年 | 156篇 |
1995年 | 171篇 |
1994年 | 142篇 |
1993年 | 152篇 |
1992年 | 130篇 |
1991年 | 124篇 |
1990年 | 105篇 |
1989年 | 104篇 |
1988年 | 102篇 |
1987年 | 102篇 |
1986年 | 80篇 |
1985年 | 81篇 |
1984年 | 80篇 |
1983年 | 62篇 |
1982年 | 58篇 |
1981年 | 45篇 |
1980年 | 44篇 |
1979年 | 42篇 |
1978年 | 39篇 |
1977年 | 29篇 |
1976年 | 32篇 |
1973年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The object of this clinical study was to investigate the circle system gas homeostasis during low-flow anaesthesia using a technique designed to keep a constant inspired oxygen fraction of 0.30. Denitrogenation was adequately accomplished with mask preoxygenation, 10 l/min, for 1 min and an initial fresh gas flow of 5 l/min for 6 min after intubation. There was no need to wash out accumulated nitrogen at intervals, since the already low nitrogen concentration in the system tended to decrease after 1 h. The fresh gas flow of nitrous oxide to oxygen ratio and the inspiratory to end-expiratory oxygen concentration difference both reflected the uptake of nitrous oxide. The calculated rates of uptake of nitrous oxide, a subject of controversy, were in accordance with those found by Severinghaus and Barton & Nunn. 相似文献
42.
烧伤感染的现状、对策与防治新动向 总被引:19,自引:3,他引:16
1 烧伤感染的现状2006年6月在昆山召开的第四届全国烧伤救治专题研讨会上,不同地区的烧伤中心或单位提供的微生物学调查资料中有不少共同点,其中很主要的一点就是:铜绿假单胞菌和金黄色葡萄球菌仍是烧伤检出菌中的主要细菌,也是我国近50年来大面积深度烧伤救治工作中难以清除的病原菌,不变中的变化是其耐药性不断增长。甲氧西林耐药金黄色葡萄球菌因被专门命名,人们对其认识较深刻,而革兰阴性杆菌耐药性的快速增长也不容忽视。革兰阴性杆菌对许多抗生素已由多重耐药性逐步发展为全耐药性;而且在多种新型抗生素的压力下,又筛选、激活了一些此前未被注意的机会致病菌。当前应特别注意的是鲍氏不动杆菌和嗜麦芽窄食单胞菌,它们正逐步成为医院感染的重要细菌。上述细菌毒力并非特别强,只因其存在天然耐药性,一旦过度繁殖,可能成为"无药可治"的难治菌。在此有必要强调,"医院感染"的含义是"患者住院后获得新的感 相似文献
43.
离子型与非离子型MR对比剂对肝脏病变的增强效果比较 总被引:2,自引:2,他引:0
目的 对比离子型钆喷酸葡胺 (Gd -DTPA)和非离子型钆双胺MR对比剂 (Gd -DTPA -BMA)在肝脏病变手推团注多时相增强扫描中的增强效果。方法 5 8例肝脏疾病患者 (男 3 1例 ,女 2 7例 ,年龄 3 0~ 77岁 )分 2组 ,第 1组 :3 0例 (男 16例 ,女 14例 ) ,采用Gd -DTPA -BMA。第 2组 :2 8例 (男 17例 ,女 11例 ) ,采用Gd -DTPA。行MR手推团注多时相增强扫描。结果 Gd -DTPA -BMA组 :增强效果满意者 2 3例 (77% ) ,增强效果一般者 6例 (2 0 % ) ,增强效果差者 1例 (3 % )。Gd -DTPA组 :增强效果满意者 2 2例(79% ) ,增强效果一般者 6例 (2 1% )。结论 在肝脏疾病MR手推团注多时相增强扫描中 ,Gd -DTPA -BMA和Gd -DTPA均可达到满意的增强效果 ,安全及有效性两者无显著性差异。Gd -DTPA -BMA粘滞度小 ,利于快速推注。 相似文献
44.
Two hundred and ten patients with clinical evidence of heartfailure, developing after an acute myocardial infarction, wererandomized to treatment with the ß1 antagonist metoprolol50100mg b.i.d. (n=106) or the ß1 partial agonistxamoterol 100200 mg bid. (n=104). Left ventricular systolicand diastolic function were assessed with echocardiography andtransmitral Doppler cardiography before and after 3 and 12 monthsof double-blind treatment. E-point septal separation and percent left ventricular fractional shortening were used as indicesof systolic function. The ratio between peak early and latemitral diastolic flow (E/A ratio) and isovolumic relaxationtime were used as indices of diastolic function. In the xamoterol group, there was a deterioration in E-pointseptal separation (P<0·05). A difference between thetreatment groups was present both at 3 months (E-point septalseparation 11·4 vs 13·0 mm, P<0·0l,fractional short ening 271 vs 252%, P<005) and 12 months(E-point septal separation Ill vs 13·2 mm, P<0·05fractional shortening 26·9 vs 25·0%, P<0·05).E/A ratio increased in the metoprolol group (P<0·05)but not in the xamoterol group. At 3 months there was a significantdifference (0·85 vs 0·67, P<0·005 betweenthe groups but not at 12 months. In comparison with the ß1-receptor antagonist metoprolol,the ß1 partial agonist xamoterol impaired left ventricularsystolic function in patients with clinical evidence of heartfailure after an acute myocardial infarction. 相似文献
45.
目的:探讨乌苯美司对小鼠药物动力学及与实验性肿瘤转移治疗活性间的关系。方法:用放射免疫法测定小鼠在不同给药途径下的乌苯美司血清药物动力学及观察乌苯美司对黑色素瘤肺转移模型的治疗活性。结果:乌苯美司iv的T12较短,初始血药浓度较高。iv和im给药后的曲线下面积较大;po及ip则较小。不同给药途径对实验性肿瘤转移均有治疗作用。结论:乌苯美司的血清T12较短,其治疗活性取决于冲击和高剂量的给药方式。 相似文献
46.
47.
本文报道五例肿瘤患者在用抗癌药的治疗过程中,出现对心脏不同程度的毒性反应,并就有关几种抗癌药物的毒性作用机理及防治进行了讨论。 相似文献
48.
抗真菌剂三氮唑含硫化合物的合成 总被引:3,自引:0,他引:3
合成了13个三氮唑含硫化合物,均为未见文献报道的新化合物,对所合成的化合物,选择三种常见真菌进行体外最低抑菌浓度(MIC)的测定,结果表明它们均有较好的抗真菌活性,有些化合物抑菌活性极高,有进一步研究和开发前景。 相似文献
49.
Topographical analysis of the EEG effects of a subconvulsive dose of lidocaine in healthy volunteers
O. DETSCH U. ERKENS U. JACOFSKY A. THIEL E. KOCHS G. HEMPELMANN 《Acta anaesthesiologica Scandinavica》1997,41(8):1039-1046
Background: The purpose of the present study was to assess the effects of intravenous lidocaine on spatial changes of electroen-cephalographic power and on psychomotoric status in conscious volunteers.
Methods: In 11 healthy volunteers lidocaine (2-min bolus, 100 mg; 15-min infusion, 40 μg kg-1 min-1 ) or placebo were given intravenously in a randomized, single-blinded, two-way crossover study. Haemodynamics and lidocaine plasma concentrations were measured at baseline and within a period of 30 min following bolus injection. Vigilance and emotional status were tested using visual analogue scales (VAS). Toxic CNS effects were evaluated by a questionnaire. The raw EEG (17 leads, reference Cz ) and computed power spectra were continuously recorded.
Results: The chosen lidocaine dosage led to nearly constant plasma concentrations (unbound lidocaine 2.5 min and 15 min after bolus 0.36±0.14 μg/ml and 0.30±0.06 μg/ml, respectively [mean±SD]). The placebo caused no symptoms, changes in VAS-scores or EEG-parameters. Lidocaine induced pronounced subjective symptoms and significant increases in delta activity for 15 min, most dominant at the frontotemporal and occipital leads (max. +219% O1 ). Frontal and occipital beta1 and beta2 power (max. +131% and +124% at O1 , respectively) was immediately increased after the bolus injection. No EEG changes occurred at central region Cz , and no interhemispheric EEG differences were noted. Theta, alphal, and alpha2 power remained unchanged.
Conclusion: The current data demonstrate simultaneous changes in psychomotoric status as well as delta and beta spectral power during lidocaine infusion. These data could be an indication that the pronounced frontotemporal and occipital EEG changes are the electroencephalographic expression of subjective sensations. 相似文献
Methods: In 11 healthy volunteers lidocaine (2-min bolus, 100 mg; 15-min infusion, 40 μg kg
Results: The chosen lidocaine dosage led to nearly constant plasma concentrations (unbound lidocaine 2.5 min and 15 min after bolus 0.36±0.14 μg/ml and 0.30±0.06 μg/ml, respectively [mean±SD]). The placebo caused no symptoms, changes in VAS-scores or EEG-parameters. Lidocaine induced pronounced subjective symptoms and significant increases in delta activity for 15 min, most dominant at the frontotemporal and occipital leads (max. +219% O
Conclusion: The current data demonstrate simultaneous changes in psychomotoric status as well as delta and beta spectral power during lidocaine infusion. These data could be an indication that the pronounced frontotemporal and occipital EEG changes are the electroencephalographic expression of subjective sensations. 相似文献
50.
There are relatively few papers which prove that one nerve anastomotic agent for the facial nerve is superior to any other. Previous experiments on the division and anastomosis of the facial nerve have failed to consider the indeterminate variables involved, i.e. operator variability, controls and the reaction of the materials on normal nerve tissue. In this experiment, a variety of anastomotic agents were tested to see if the anastomotic agents themselves affected the extra-temporal facial nerve function. The absorbable suture, non-absorbable suture, glue and tube wrap used had no effect on normal nerve tissue or on the anastomosis of the sectioned facial nerve of the rat compared with simple laying together of the divided ends of the divided nerve. 相似文献