全文获取类型
收费全文 | 7154篇 |
免费 | 422篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 225篇 |
妇产科学 | 186篇 |
基础医学 | 1065篇 |
口腔科学 | 212篇 |
临床医学 | 656篇 |
内科学 | 1401篇 |
皮肤病学 | 126篇 |
神经病学 | 783篇 |
特种医学 | 263篇 |
外科学 | 861篇 |
综合类 | 57篇 |
一般理论 | 8篇 |
预防医学 | 511篇 |
眼科学 | 154篇 |
药学 | 532篇 |
中国医学 | 10篇 |
肿瘤学 | 463篇 |
出版年
2022年 | 54篇 |
2021年 | 119篇 |
2020年 | 94篇 |
2019年 | 130篇 |
2018年 | 154篇 |
2017年 | 123篇 |
2016年 | 161篇 |
2015年 | 148篇 |
2014年 | 201篇 |
2013年 | 322篇 |
2012年 | 450篇 |
2011年 | 453篇 |
2010年 | 285篇 |
2009年 | 273篇 |
2008年 | 418篇 |
2007年 | 468篇 |
2006年 | 426篇 |
2005年 | 423篇 |
2004年 | 407篇 |
2003年 | 330篇 |
2002年 | 374篇 |
2001年 | 63篇 |
2000年 | 64篇 |
1999年 | 80篇 |
1998年 | 96篇 |
1997年 | 71篇 |
1996年 | 72篇 |
1995年 | 60篇 |
1994年 | 72篇 |
1993年 | 60篇 |
1992年 | 58篇 |
1991年 | 50篇 |
1990年 | 52篇 |
1989年 | 38篇 |
1988年 | 49篇 |
1987年 | 33篇 |
1986年 | 56篇 |
1985年 | 52篇 |
1984年 | 52篇 |
1983年 | 36篇 |
1982年 | 41篇 |
1981年 | 58篇 |
1980年 | 40篇 |
1979年 | 47篇 |
1978年 | 34篇 |
1977年 | 35篇 |
1975年 | 29篇 |
1974年 | 30篇 |
1973年 | 36篇 |
1967年 | 27篇 |
排序方式: 共有7610条查询结果,搜索用时 15 毫秒
11.
Heparin or heparan sulfate--what is the difference? 总被引:3,自引:0,他引:3
12.
13.
We describe how adverse drug reactions (ADRs) can play an important role in pharmaceutical research and drug development. Not only do ADRs represent the risks and drawbacks associated with drugs but they can also be related to other knowledge available in pharmaceutical and medical research. We offer a model that can be used to systematically map the pathways through which ADRs can lead to innovative research. These pathways include chemical, therapeutic or pathophysiological steps that can be taken to arrive at new knowledge based on ADRs. We used the development of angiotensin-converting enzyme inhibitors, especially captopril, as a case study. The similarity between the ADR profiles of captopril and penicillamine was a starting point for further innovation. Historical analysis shows that in several instances research in the field of angiotensin-converting enzyme inhibitors has been triggered by ADRs. The model presented here might be applicable to other areas of innovative drug research. 相似文献
14.
15.
Rainer O. Seidl Ingo Todt Arne Ernst 《European archives of oto-rhino-laryngology》2007,264(3):291-293
We report on a case of esophageal atresia following cervical spine surgery. A swallowing examination was performed using fibre-optic
endoscopy and videofluoroscopy. There was scar tissue fixation of the larynx and esophagus to the cervical spine. Operative
mobilization of the larynx and esophagus and formation of a sliding layer using a platysma-fascia flap was done. The PEG and
tracheal cannula were removed; oral nutrition was initiated after 3 months. Swallowing disorders following operations on the
upper cervical spine should be investigated. Careful preparation that preserves the layers should be carried out. Fixation
of tissues as a result of scarring should be treated with a sliding layer. 相似文献
16.
Per Hartvig S.Å. Eckernäs Leif Lindström Bengt Ekblom Ulf Bondesson Hans Lundqvist Christer Halldin Kjell Någren Bengt Långström 《Psychopharmacology》1986,89(2):248-252
By means of positron emission tomography the uptake and kinetics of N-(methyl-11C)clozapine in different brain regions have been studied in Rhesus monkeys. 11C-clozapine rapidly entered the brain and maximum radioactive uptake was seen 5–12 min after administration. Highest uptake was measured in the striatum. Other regions with an uptake higher than in the cerebellum were thalamus and mesencephalon. The radioactivity from different brain regions decreased with an elimination half-life of about 5 h and parallelled the plasma kinetics of unlabelled clozapine. The striatum/cerebellum ratio of 11C-clozapine-derived radioactivity remained constant during the period studied and did not change after pretreatment with atropine. In contrast, the striatum/cerebellum ratio was somewhat lower after pretreatment with N-methylspiperone (NMSP), indicating competition for the same binding sites in the striatum. After pretreatment with increasing doses of clozapine, a dose-dependent protection of binding sites in the striatum for 11C-NMSP was seen. It is concluded that clozapine is more loosely bound to dopamine receptors in the striatum than N-methylspiperone and that the kinetics of clozapine in the brain parallel that in the plasma. The binding properties of clozapine within the brain may explain some of the clinical properties of the drug. 相似文献
17.
Interactions between 5-hydroxytryptamine (5-HT) and substance P (SP) in the mouse spinal cord were investigated using the tail-flick test and the behavioral response evoked by intrathecal (i.th.) SP or i.th. 5-HT. I.th. injection of 5-HT (20 μg) or the 5-HT1 receptor agonists(+)-8-hydroxy-2-(di-n-propylamino)tetralin ((+)-8-OH-DPAT) (20 μg) or 5-methoxy-3(1,2,3,6-tetrahydropyridine-4-yl)-1H-indole (RU 24969) (20 μg) markedly inhibited the tail-flick reflex. The effect of these compounds was reduced when SP (5 μg) was given i.th. 55 min, or 55 and 45 min before the agonists. The tail-flick latencies recorded 5 min before injection of a 5-HT agonist were similar in animals treated with SP or vehicle. The changes in the tail-flick test were not due to changes in tail skin temperature since only minimal differences in the skin temperature were recorded between the groups injected with SP or vehicle. I.th. injection of SP (10 ng) or 5-HT (2 μg) produced a similar behavioral response consisting of biting, licking and scratching of the caudal part of the body, indicative of nociceptive stimulation. The responses both to i.th. SP and 5-HT were reduced after i.th. application of SP receptor antagonist [d-Arg1,d-Trp7,9,Leu11]-SP (Spantide) (5 μg), as well as 5 min after i.th. injection of the 5-HT receptor antagonist metergoline (4 μg). The data may indicate functional interactions between SP and 5-HT in the mouse spinal cord, which may take place in neurons involved in the processing of nociception. 相似文献
18.
The cytotoxicity of extracts from rice cultures of five Fusarium avenaceum strains against the porcine epithelial kidney cell-line PK-15 was investigated using the Alamar Blue™ assay. After the identification of known fungal metabolites, cytotoxic extracts were fractionated using semi-preparative reversed-phase HPLC and normal phase LC, and the fractions were tested for cytotoxicity. In this way, two different groups of metabolites were identified as the major cytotoxic principles of the extracts. High concentrations of enniatins, especially enniatins B and B1, inhibited the metabolic activity of PK-15 cells. Furthermore, an unidentified metabolite, produced in high amounts by a strain that produced relatively small amounts of enniatins, was also found to be cytotoxic to PK-15 cells. This study shows that enniatins, a group of cyclic depsipeptides, which have been ignored as significant contributors to the toxicity of fungal extracts, may account for most of the observed effect for F. avenaceum. 相似文献
19.
20.
Steven G. E. Marsh Ekkehard D. Albert Walter F. Bodmer Ronald E. Bontrop Bo Dupont Henry A. Erlich Daniel E. Geraghty John A. Hansen Bernard Mach Wolfgang R. Mayr Peter Parham Effie W. Petersdorf Takehiko Sasazuki Geziena M. Th. Schreuder Jack L. Strominger Arne Svejgaard Paul I. Terasaki 《International journal of immunogenetics》2002,29(6):463-515