全文获取类型
收费全文 | 1011篇 |
免费 | 61篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 65篇 |
妇产科学 | 18篇 |
基础医学 | 135篇 |
口腔科学 | 24篇 |
临床医学 | 115篇 |
内科学 | 316篇 |
皮肤病学 | 10篇 |
神经病学 | 35篇 |
特种医学 | 171篇 |
外科学 | 50篇 |
综合类 | 12篇 |
预防医学 | 45篇 |
眼科学 | 9篇 |
药学 | 58篇 |
中国医学 | 1篇 |
肿瘤学 | 42篇 |
出版年
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 22篇 |
2013年 | 32篇 |
2012年 | 33篇 |
2011年 | 32篇 |
2010年 | 43篇 |
2009年 | 48篇 |
2008年 | 31篇 |
2007年 | 44篇 |
2006年 | 23篇 |
2005年 | 33篇 |
2004年 | 19篇 |
2003年 | 13篇 |
2002年 | 26篇 |
2001年 | 19篇 |
2000年 | 22篇 |
1999年 | 16篇 |
1998年 | 52篇 |
1997年 | 49篇 |
1996年 | 45篇 |
1995年 | 40篇 |
1994年 | 43篇 |
1993年 | 30篇 |
1992年 | 17篇 |
1991年 | 28篇 |
1990年 | 23篇 |
1989年 | 31篇 |
1988年 | 37篇 |
1987年 | 17篇 |
1986年 | 27篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1971年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有1109条查询结果,搜索用时 15 毫秒
81.
82.
Miriam Hoekstra Mathijs Vogelzang José T Drost Marcel Janse Bert G Loef Iwan CC van der Horst Felix Zijlstra Maarten WN Nijsten 《BMC medical informatics and decision making》2010,10(1):5
Background
Potassium disorders can cause major complications and must be avoided in critically ill patients. Regulation of potassium in the intensive care unit (ICU) requires potassium administration with frequent blood potassium measurements and subsequent adjustments of the amount of potassium administrated. The use of a potassium replacement protocol can improve potassium regulation. For safety and efficiency, computerized protocols appear to be superior over paper protocols. The aim of this study was to evaluate if a computerized potassium regulation protocol in the ICU improved potassium regulation. 相似文献83.
84.
The complete development in vitro of the vertebrate phase of the mammalian malarial parasite Plasmodium berghei 总被引:1,自引:0,他引:1
A Suhrbier C Janse B Mons S L Fleck J Nicholas C S Davies R E Sinden 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1987,81(6):907-909
All three 'vertebrate' stages of the rodent malarial parasite Plasmodium berghei berghei were grown in vitro in the absence of the vertebrate host. The parasite was introduced into culture from infected mosquitoes and 2 in vitro culture methods were used sequentially to complete the 'vertebrate' phases of development in hepatoma and erythrocyte host cells. The resultant blood infection produced mature schizonts and male and female gametocytes. The protocol, which is now being extended to the human pathogen P. falciparum, may assist future studies on this important group of parasites. 相似文献
85.
86.
目的探讨医源性脾脏损伤脾切除对结直肠癌切除患者术后长期生存的影响。方法对1990年1月1日至1999年12月31日10年间行结直肠癌手术切除并附带脾切除患者进行病例配对回顾研究。分析患者年龄、性别、依据美国麻醉学医师协会(ASA)标准评估的身体状况、疾病分期、手术类型及预后等资料。配对病例来自同一医疗中心,性别、年龄、疾病分期及手术类型完全相同。手术附带脾切除患者为试验组,未切脾者为对照组。结果55例患者行医源性脾切除术,对照组在年龄、性别、身体状况、疾病分期及手术类型上与之匹配。随访时间(从手术开始到患者死亡或者最后一次随访1为2~205个月(中位随访时间为43个月)。Cox比例危险度模型进行Kaplan-Meier法生存分析发现两组间差异有显著性意义,不切除脾脏对患者生存有利(危险度1.8,95%可信区间为1-3.3,P=0.0399),未切脾组与切脾组5年生存率分别为70%和47%,10年生存率分别为55%和38%。结论结直肠癌患者在行结肠或直肠切除时,因医源性脾脏损伤而切除脾脏者,预后较差。 相似文献
87.
88.
Age-related changes in electrotonic coupling ratio of two identified neurons in Lymnaea stagnalis were studied together with the underlying changes in the steady-state conductance properties of the network. Two phases were distinguished in the development of coupling ratio across lifespan. During the first phase (age of 3-13 months), coupling ratio decreased from decreased from 60% to 30%. The second phase (age 13-20 months) was characterized by an increase in coupling ratio. Values of up to 60% were reached again in the oldest animals. Voltage clamp measurements showed that the biphasic trend of the age-related changes in coupling ratio is paralleled by changes in conductance properties of the junction between VD1 and RPD2. During the first phase junctional conductance decreased, whereas during the second phase junctional conductance increased. In addition to the decrease in junctional conductance, a growth-related increase in non-junctional conductance of VD1 and RPD2 contributed to the decrease in coupling ratio observed during the first phase. Thus our results indicate that in Lymnaea junctional connections between neurons may undergo considerable and discontinuous changes after sexual maturation. In addition to these changes in steady-state electrical properties, indications were obtained that age-related changes of kinetically slower conductance(s) may occur in the non-junctional membrane of VD1 and RPD2. 相似文献
89.
Superparamagnetic iron oxide-enhanced MR imaging: pulse sequence optimization for detection of liver cancer 总被引:3,自引:0,他引:3
Fretz CJ; Elizondo G; Weissleder R; Hahn PF; Stark DD; Ferrucci JT Jr 《Radiology》1989,172(2):393-397
The effects of magnetic resonance (MR) pulse sequences and timing parameters on tumor-liver contrast were studied in an animal model of metastatic liver cancer. Six spin-echo (SE), three inversion-recovery (IR), and four gradient-echo (GRE) sequences were evaluated at 0.6 T before and after injection of super-paramagnetic iron oxide. GRE techniques, irrespective of echo time and flip angle, showed the greatest change in signal intensity (enhancement) of the liver after administration of iron oxide. Single-acquisition GRE sequences (16 seconds) matched the contrast-to-noise ratio (C/N) performance of the most effective 6.4-minute SE sequences. Multiexcitation GRE sequences showed tumor-liver C/Ns per unit time that were significantly (P less than .05) higher than those achieved with SE and IR sequences. GRE sequences, which recruit intravoxel dephasing as an additional source of transverse relaxation enhancement (T2*), show a higher C/N per unit time and in this respect seem superior to SE and IR sequences for MR imaging with superparamagnetic iron oxide. 相似文献
90.
TEELUCKSINGH S; STEER CR; THOMPSON CJ; SECKL JR; DOUGLAS NJ; EDWARDS CRW 《QJM : monthly journal of the Association of Physicians》1991,78(2):185-190
We describe a young man who developed extensive hypothalamicdysfunction including diabetes insipidus, adipsia, hyperprolactinaemia,and poikiliothermia together with central sleep apnoea followingexposure to toluene. 相似文献