全文获取类型
收费全文 | 34309篇 |
免费 | 2341篇 |
国内免费 | 856篇 |
专业分类
耳鼻咽喉 | 310篇 |
儿科学 | 423篇 |
妇产科学 | 393篇 |
基础医学 | 1572篇 |
口腔科学 | 4137篇 |
临床医学 | 2383篇 |
内科学 | 3793篇 |
皮肤病学 | 400篇 |
神经病学 | 2079篇 |
特种医学 | 380篇 |
外国民族医学 | 1篇 |
外科学 | 1375篇 |
综合类 | 3536篇 |
一般理论 | 3篇 |
预防医学 | 2354篇 |
眼科学 | 163篇 |
药学 | 10588篇 |
13篇 | |
中国医学 | 2090篇 |
肿瘤学 | 1513篇 |
出版年
2024年 | 161篇 |
2023年 | 675篇 |
2022年 | 989篇 |
2021年 | 1344篇 |
2020年 | 1257篇 |
2019年 | 1555篇 |
2018年 | 1636篇 |
2017年 | 1347篇 |
2016年 | 1227篇 |
2015年 | 1150篇 |
2014年 | 2414篇 |
2013年 | 3121篇 |
2012年 | 2057篇 |
2011年 | 2326篇 |
2010年 | 1686篇 |
2009年 | 1538篇 |
2008年 | 1442篇 |
2007年 | 1447篇 |
2006年 | 1164篇 |
2005年 | 1061篇 |
2004年 | 872篇 |
2003年 | 838篇 |
2002年 | 583篇 |
2001年 | 590篇 |
2000年 | 441篇 |
1999年 | 391篇 |
1998年 | 368篇 |
1997年 | 318篇 |
1996年 | 315篇 |
1995年 | 280篇 |
1994年 | 232篇 |
1993年 | 233篇 |
1992年 | 246篇 |
1991年 | 173篇 |
1990年 | 177篇 |
1989年 | 138篇 |
1988年 | 147篇 |
1987年 | 99篇 |
1986年 | 109篇 |
1985年 | 236篇 |
1984年 | 185篇 |
1983年 | 130篇 |
1982年 | 142篇 |
1981年 | 90篇 |
1980年 | 93篇 |
1979年 | 75篇 |
1978年 | 81篇 |
1977年 | 68篇 |
1976年 | 58篇 |
1975年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Carl J O'Kane Douglas C Tutt Lyndon A Bauer 《Emergency medicine Australasia : EMA》2002,14(3):296-303
Cannabis and driving is an emerging injury‐prevention concern. The incidence of driving while affected by cannabis is rising in parallel with increased cannabis use in the community. Younger drivers are at particular risk. Improvements in research methodology, technology and laboratory testing methods have occurred in the last 10 years. These cast doubt on earlier results and conclusions. Studies now show that cannabis has a significant impairing effect on driving when used alone and that this effect is exaggerated when combined with alcohol. Of particular concern is the presence of cannabis as the sole psychoactive drug in an increasing number of road fatalities and the lack of any structural response to this problem. A review of testing methods, laboratory and real driving studies, and recent epidemiological studies is presented. Suggestions for methods of further data collection and future public policy are made. 相似文献
42.
Herman H. Samson Gerald A. Tolliver Miki Haraguchi Peter W. Kalivas 《Brain research bulletin》1991,27(2):267-271
Rats, initiated to self-administer 10% (v/v) ethanol in an operant situation using the sucrose-fading procedure, received bilateral n. accumbens microinjections of d-amphetamine prior to operant sessions. Doses of 4 micrograms, 10 micrograms and 20 micrograms/brain were administered and some animals also received a 4 microgram/brain dose of LY171555. Three different effects were observed: increased, decreased and no change in total session responding. There was no clear relation between injection area in the n. accumbens and type of effect observed. For either an increase or decrease in total session responding, momentary response rates were decreased. Both d-amphetamine and LY171555 produced similar results. The data support the hypothesis that dopamine in the n. accumbens is involved with ethanol reinforced operant responding but in a complex manner. 相似文献
43.
目的 研究异型增生程度不同的口腔白斑和不同分级的鳞癌中谷胱苷肽S转移酶π(GST π)的表达 ,探讨GST π在口腔鳞癌发生发展中的作用。 方法 采用免疫S -P法 ,对 5 4例轻、中、重度异型增生 ,4 7例高、中、低分化的口腔鳞癌 ,7例口腔粘膜上皮单纯增生患者组织进行GST π检测。 结果 口腔粘膜上皮单纯增生组织中未见GST π的表达 ,轻、中、重度异型增生病例中的GST π阳性率分别为4 7.8%、5 2 .9%和 6 4 .2 % ,高于单纯增生组 (P <0 .0 1) ;高分化鳞癌GST π阳性率为 6 4 .7% ,中、低分化鳞癌组分别为 2 8.5 %及 2 2 .2 % ,中、低分化鳞癌组表达均低于高分化鳞癌组及异型增生组 (P <0 .0 5 )。 结论 GST π表达的变化与口腔鳞癌早期的发生发展密切相关 相似文献
44.
目的 了解肿瘤住院患者使用免疫调节药的现状,为临床合理用药提供参考。方法对2003~2005年免疫调节药应用情况运用药物使用频度(DDDs)、年均增率(AARG)等分析方法,进行统计分析。结果 免疫调节药销售金额年均增长率达106.69%。生物反应修饰剂销售金额占总金额的65.93%。生物反应修饰剂和增强免疫功能中成药用药频度相当。排序靠前的是金黄色葡萄球菌滤液注射液、参芪扶正注射液,用量上升最快的是香菇多糖注射液、胸腺素α1注射液。结论 免疫调节药是肿瘤放化疗必备用药,在肿瘤患者住院治疗中应用广泛。整体上该类药物的应用基本合理。疗效显著且作用广泛的药物成为临床首选。 相似文献
45.
The toxic effects of nitroquine-dapsone compound(NQD)in mice and dogs were studied.The therapeutic index of NQDin mice is 1911,the greatest among the 6 antimalarials tested.Thetoxic effects of NQD(50 mg/kg/day for 3 days per os)and nitro-quine in dogs were manifested by injuries on the adrenal cortexand intestinal epithelium.When folic acid(4 mg/kg/day for 4 days)or calcium leucovorinum(0.3 mg/kg/day for 4 days)were usedconcomitantly with NQD,the death rate and the incidence of dia-rrhea in the toxicated dogs were greatly reduced,the injury on theintestinal epithelium was much milder,and the goblet cells weremuch more numerous than those without treatment.The results suggestthat folic acid and calcium leucovorinum can protect the undifferen-tiated cells in the intestinal crypts from being injured by NQD. 相似文献
46.
47.
包含颈外静脉的颈阔肌肌皮瓣修复口腔癌切除后缺损 总被引:1,自引:0,他引:1
目的探讨将颈外静脉包含在颈阔肌肌皮瓣内修复口腔癌切除后缺损的手术方法。方法先形成蒂在颌缘下包含颈外静脉的颈阔肌肌皮瓣,待口腔肿瘤切除后,将肌皮瓣经口底隧道引入口腔修复缺损。结果临床应用17例,肌皮瓣均无血运障碍,100%存活,其中有2例发生口面痿,经换药后痿口完全闭合。结论将颈外静脉包含在颈阔肌肌皮瓣内有助于肌皮瓣血循环的改善和存活率的提高。 相似文献
48.
Robert M. Levy Roman Saikovsky Evgeniya Shmidt Alexander Khokhlov Bruce P. Burnett 《Nutrition Research》2009
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups. 相似文献
49.
W A Turski M Dziki E Urbanska L S Calderazzo-Filho E A Cavalheiro 《Synapse (New York, N.Y.)》1991,7(3):173-180
Systemic (s.c.) administration of aminooxyacetic acid (AOAA) in mice triggered clonic convulsions with a CD50 (convulsive dose) of 68 mg/kg (range 54-86). AOAA also induced clonic convulsions in mice subjected to intracerebroventricular administration of the drug with a CD50 of 0.04 mumols (range 0.028-0.06). At the onset of convulsions induced by systemic AOAA (CD97;150 mg/kg), the GAD activity in the frontal cortex and hippocampus was not affected. GABA mimetic drugs, progabide and gabaculine, had no effect on convulsions induced by AOAA. Convulsions induced by systemic administration of AOAA were blocked by diazepam, phenobarbital, and valproate. Ethosuximide, trimethadione, acetazolamide, diphenylhydantoin, and carbamazepine remained ineffective. L-Phenylisopropyladenosine was also found to protect mice against AOAA-induced convulsions, whereas atropine and baclofen had no effect. The seizures induced by intracerebroventricular administration of AOAA (CD97; 0.1 mumols) were blocked by coadministration of preferential N-methyl-D-aspartate antagonists, D-(-)-2-aminophosphonoheptanoic (AP7), 3-[+/-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonic (CPP), and kynurenic acid (KYNA); preferential quisqualate/kainate antagonists, 6-cyano-7-nitro-quinoxaline-2,3-dione and gamma-D-glutamylaminomethylsulphonic acid, remained inactive in the range of dosages sufficient to block seizures induced by quisqualic acid or kainic acid. The antagonistic action of antiepileptic drugs effective against seizures induced by excitatory amino acids (diazepam and valproate), and drugs acting on excitatory amino acid receptors (AP7, CPP, and KYNA) upon seizures induced by AOAA suggests an involvement of excitatory neurotransmission in the convulsant action of the drug. 相似文献
50.
Despite the use of gold complexes in modern medicine for over 100 years and the use of gold complexes in the management of
rheumatoid disease for more than 60 years, the definitive mechanisms of action for efficacy and for toxicity have not been
established.
Gold is a group 1b metal in the periodic table with several oxidation states but it is only Au(I) which is active in the biological
milieu. Gold sodium thiomalate is not only a polymeric structure, but also has the chiral ligand, thiomalic acid. Gold sodium
thiomalate thus can exist in several different physical states which may have different biological activity. In addition the
pharmacokinetic profile of gold complexes has been of little value in the understanding of either the mechanism of action,
efficacy or toxicity for both the injectable and the oral gold complexes. Many authors have misinterpreted research data on
the activities of gold complexes because they compared gold complexes of different structures, and gold complexes which exist
at different pH.
Experimental work in our laboratory has identified that gold sodium thiomalate is a mixture and can exist as either a yellow
or a colourless solution. These have some similar but several different biological activities.
Many factors contribute to the lack of understanding of the action of gold complexes. Some of these factors are related to
the wide variation in physical structure and biological activities exhibited by these compounds. 相似文献