全文获取类型
收费全文 | 9862篇 |
免费 | 588篇 |
国内免费 | 256篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 87篇 |
妇产科学 | 218篇 |
基础医学 | 668篇 |
口腔科学 | 342篇 |
临床医学 | 1601篇 |
内科学 | 1096篇 |
皮肤病学 | 129篇 |
神经病学 | 337篇 |
特种医学 | 418篇 |
外国民族医学 | 1篇 |
外科学 | 2793篇 |
综合类 | 890篇 |
预防医学 | 681篇 |
眼科学 | 190篇 |
药学 | 632篇 |
5篇 | |
中国医学 | 204篇 |
肿瘤学 | 301篇 |
出版年
2024年 | 16篇 |
2023年 | 148篇 |
2022年 | 231篇 |
2021年 | 340篇 |
2020年 | 315篇 |
2019年 | 343篇 |
2018年 | 349篇 |
2017年 | 283篇 |
2016年 | 349篇 |
2015年 | 289篇 |
2014年 | 603篇 |
2013年 | 561篇 |
2012年 | 487篇 |
2011年 | 552篇 |
2010年 | 450篇 |
2009年 | 422篇 |
2008年 | 428篇 |
2007年 | 461篇 |
2006年 | 398篇 |
2005年 | 334篇 |
2004年 | 317篇 |
2003年 | 294篇 |
2002年 | 226篇 |
2001年 | 237篇 |
2000年 | 141篇 |
1999年 | 156篇 |
1998年 | 126篇 |
1997年 | 135篇 |
1996年 | 152篇 |
1995年 | 111篇 |
1994年 | 120篇 |
1993年 | 126篇 |
1992年 | 115篇 |
1991年 | 138篇 |
1990年 | 108篇 |
1989年 | 99篇 |
1988年 | 119篇 |
1987年 | 80篇 |
1986年 | 92篇 |
1985年 | 86篇 |
1984年 | 80篇 |
1983年 | 64篇 |
1982年 | 53篇 |
1981年 | 47篇 |
1980年 | 64篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1975年 | 6篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
H. H. LUTTROPP R. THOMASSON S. DAHM J. PERSSON O. WERNER 《Acta anaesthesiologica Scandinavica》1994,38(2):121-125
Xenon is a more potent anesthetic than nitrous oxide, and gives more profound analgesia. This investigation was performed to assess the potential of xenon for becoming an anesthetic inspite of its high manufacturing cost. Seven ASA I—-II patients undergoing cholecystectomy (n = 4), hernia repair (n = 2), or mammoplasty (n=l) were studied. Denitrogenation by 15–20 min of oxygen breathing under propofol anesthesia was followed by fentanyl–supplemented xenon anesthesia administered via an automatic minimal flow system which held the oxygen concentration at 30%. Xenon anesthesia lasted 76–228 min and 8–14 1 of xenon (ATPD) was used, of which 5.6–8.1 1 was expended during the first 15 min. Anesthesia appeared to be satisfactory, and the patients woke up rapidly after xenon was discontinued. The automatic system made minimal flow xenon anesthesia easy to administer, but nitrogen accumulation is still a problem. Assuming a xenon price of 10 US $ per litre, the average cost for xenon was about 65 US $ for the first 15 min and then about 25 USS for each subsequent hour of anesthesia. 相似文献
62.
目的 探索LDH实验检测细胞活力的可行性。方法 原代培养骨髓细胞和软骨细胞,用LDH实验测定上述两组细胞的活力,并与镜下活体观察到细胞的生长状况相比较。与目前比较成熟的测定细胞活力的MTS实验的测得的值相比较。结果 LDH实验对上述两组细胞的活力的测定结果与镜下活体观察到的结果相符合。与MTS实验的测得的结果经统计学处理无显著差异。结论 LDH实验可用于细胞活力的直接测定,而对活细胞的生存、繁殖无影响。 相似文献
63.
64.
Michael S. Runyon MD Peter B. Richman MD Jeffrey A. Kline MD 《Academic emergency medicine》2007,14(1):53-57
Background Several clinical decision rules (CDRs) have been validated for pretest probability assessment of pulmonary embolism (PE), but the authors are unaware of any data quantifying and characterizing their use in emergency departments. Objectives To characterize clinicians' knowledge of and attitudes toward two commonly used CDRs for PE. Methods By using a modified Delphi approach, the authors developed a two‐page paper survey including 15 multiple‐choice questions. The questions were designed to determine the respondents' familiarity, frequency of use, and comprehension of the Canadian and Charlotte rules. The survey also queried the frequency of use of unstructured (gestalt) pretest probability assessment and reasons why physicians choose not to use decision rules. The surveys were sent to physicians, physician assistants, and medical students at 32 academic and community hospitals in the United States and the United Kingdom. Results Respondents included 555 clinicians; 443 (80%) work in academic practice, and 112 (20%) are community based. Significantly more academic practitioners (73%) than community practitioners (49%) indicated familiarity with at least one of the two decision rules. Among all respondents familiar with a rule, 50% reported using it in more than half of applicable cases. A significant number of these respondents could not correctly identify a key component of the rule (23% for the Charlotte rule and 43% for the Canadian rule). Fifty‐seven percent of all respondents indicated use of gestalt rather than a decision rule in more than half of cases. Conclusions Academic clinicians were more likely to report familiarity with either of these two specific decision rules. Only one half of all clinicians reporting familiarity with the rules use them in more than 50% of applicable cases. Spontaneous recall of the specific elements of the rules was low to moderate. Future work should consider clinical gestalt in the evaluation of patients with possible PE. 相似文献
65.
This report describes a technique in which deep-seated CNS neoplasms, the volume and shape of which had been determined and stereotactically localized by computer reconstruction of CT data, were vaporized with a carbon dioxide laser attached to a stereotactic frame. The clinical results with 6 patients treated by this technique are presented. 相似文献
66.
目的 分析 5种常用的肌腱保存方法对肌腱生物力学的影响。从生物力学的角度寻找最佳的保存方法 ,用于指导临床肌腱移植。方法 采用 5 0只健康白色Leghorn鸡 ,随机分成 5组 ,建立 2 ,3 ,4爪浅屈肌腱做供体模型。分别采用常用的保存组织方法 :低温冷藏 ,70 %酒精 ,10 %福尔马林 ,85 %甘油。结果 低温冷藏组在最大抗拉伸力Pmax及最大延伸率δmax与新鲜肌腱组比较 ,无明显差异。酒精组、85 %甘油组最大抗拉伸力较高 ,而福尔马林组最低。结论 低温冷藏的方法保存肌腱 ,从生物力学角度考虑是最佳的保存方法 相似文献
67.
The ionic mechanisms of the effect of extracellularly ejected recombinant human tumor necrosis factor-alpha (rhTNF-alpha) on the membrane of identified neurons R9 and R10 of Aplysia kurodai was investigated with conventional voltage-clamp, micropressure ejection, and ion substitution techniques. Micropressure-ejected rhTNF caused a marked hyperpolarization in the unclamped neuron. Clamping the same neuron at it resting potential level (-60 mV) and reejecting rhTNF-alpha with the same dose produced a slow outward current [Io (TNF)] associated with a decrease in input membrane conductance. Io (TNF) was decreased by depolarization and increased by hyperpolarization. The extrapolated reversal potential of Io (TNF) was approximately +10 mV. Ion substitution and pharmacological experiments suggest that Io (TNF) in identified neurons R9 and R10 of A. kurodai is due to a decreased Na+ conductance but not due to an activation of the Na(+)-K+ pump. Our results demonstrate that the immunomodulator TNF can act directly on the nervous system as well as on the immune system. 相似文献
68.
Plasma volume estimation using indocyanine green with biexponential regression analysis of the decay curves 总被引:2,自引:0,他引:2
We studied seven analytical methods of estimating the plasma volume from the decay curves of indocyanine green. Fifteen volunteers received 1.0 mgkg−1 of the dye by intravenous injection and the plasma concentration was measured continuously using spectrophotometry. Plasma volumes were calculated using three single-regression methods (1-a, 1-b, 1-c) and four biexponential regression methods (2-a, 2-b, 2-c, 2-d). The means (SD) of 1-a, 1-b and 1-c were 39 (5.0), 44 (5.7) and 54 (11.5) mlkg−1 , respectively, and these were significantly different from each other (p < 0.05). The values for methods 2-b, 2-c and 2-d were similar to each other: 39 (4.6), 40 (4.1) and 40 (4.0) mlkg−1 , respectively. These required more than 3 min circulation or mixing time. When the time allowed for mixing was less than 3 min (method 2-a) the plasma volume was underestimated. We conclude that plasma volume estimation using indocyanine green and spectrophotometry is most accurate when the mixing time is adequate (3–5 min) and the decay curves are analysed using biexponential regression. 相似文献
69.
Unilateral epidural analgesia occurring in a parturient three times in successive pregnancies is reported. Possible causes are reviewed, and clinical and radiological evidence in support of the most likely explanation are presented. 相似文献
70.
The influence of epidural administration of fentanyl infusion on gastric emptying in labour 总被引:1,自引:0,他引:1
The effect of epidural infusions containing fentanyl on maternal gastric emptying in labour was examined using the rate of paracetamol absorption. Women were randomly allocated to receive one of two epidural infusions, bupivacaine 0.125% alone or bupivacaine 0.0625% with fentanyl 2.5 μgml−1 at a rate of 10–12 mlh−1 . Paracetamol 1.5 g was given orally to women after either 30 ml of the infusion solution had been given (mean time 2.5 h, study A) or 40–50 ml (mean time 4.5 h, study B). Six venous blood samples were taken over the next 90 min for measurement of plasma paracetamol concentration. There were no significant differences in maximum plasma paracetamol concentration, time to maximum paracetamol concentration and area under the concentration–time curve between the two groups for study A. In study B the time to maximum plasma paracetamol concentration was significantly delayed in women receiving > 100 μg fentanyl compared with controls (p < 0.05). We conclude that the dose of fentanyl that may delay gastric emptying when given by epidural infusion is greater than 100 μg. 相似文献