全文获取类型
收费全文 | 1702篇 |
免费 | 114篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 40篇 |
妇产科学 | 9篇 |
基础医学 | 265篇 |
口腔科学 | 45篇 |
临床医学 | 141篇 |
内科学 | 331篇 |
皮肤病学 | 27篇 |
神经病学 | 204篇 |
特种医学 | 90篇 |
外国民族医学 | 2篇 |
外科学 | 295篇 |
综合类 | 7篇 |
一般理论 | 9篇 |
预防医学 | 90篇 |
眼科学 | 15篇 |
药学 | 132篇 |
中国医学 | 2篇 |
肿瘤学 | 105篇 |
出版年
2021年 | 25篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2018年 | 28篇 |
2017年 | 15篇 |
2016年 | 29篇 |
2015年 | 29篇 |
2014年 | 29篇 |
2013年 | 38篇 |
2012年 | 68篇 |
2011年 | 60篇 |
2010年 | 46篇 |
2009年 | 40篇 |
2008年 | 77篇 |
2007年 | 86篇 |
2006年 | 68篇 |
2005年 | 77篇 |
2004年 | 66篇 |
2003年 | 51篇 |
2002年 | 57篇 |
2001年 | 63篇 |
2000年 | 52篇 |
1999年 | 47篇 |
1998年 | 25篇 |
1997年 | 38篇 |
1996年 | 22篇 |
1995年 | 20篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 28篇 |
1991年 | 32篇 |
1990年 | 30篇 |
1989年 | 32篇 |
1988年 | 31篇 |
1987年 | 31篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 11篇 |
1983年 | 24篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1975年 | 19篇 |
1974年 | 15篇 |
1973年 | 17篇 |
1971年 | 18篇 |
1970年 | 20篇 |
1968年 | 10篇 |
排序方式: 共有1820条查询结果,搜索用时 15 毫秒
11.
12.
Sensitivity to triazolam in the elderly 总被引:8,自引:0,他引:8
D J Greenblatt J S Harmatz L Shapiro N Engelhardt T A Gouthro R I Shader 《The New England journal of medicine》1991,324(24):1691-1698
BACKGROUND. Elderly persons frequently appear to be sensitive to the effects of many drugs that depress the central nervous system. We studied the effect of age on the pharmacokinetics and pharmacodynamics of the benzodiazepine hypnotic agent triazolam, now the most frequently prescribed hypnotic drug in the United States. METHODS. Twenty-six healthy young subjects (mean age, 30 years) and 21 healthy elderly subjects (mean age, 69 years) participated in a four-way crossover study. After a single-blind adaptation trial with placebo, each subject received, in random order and in double-blind fashion, single doses of placebo, 0.125 mg of triazolam, and 0.25 mg of triazolam. For 24 hours after the administration of each of the three study medications, plasma triazolam levels were determined and psychomotor performance, memory, and degree of sedation were assessed. RESULTS. Plasma triazolam concentrations increased in proportion to the dose, but the elderly subjects had higher plasma concentrations due to reduced clearance of the drug. The degree of sedation as rated by an observer and the reduction in the subjects' performance on the digit-symbol substitution test were both greater in the elderly than in the young subjects after they were given the same doses. The relation of the plasma triazolam concentration to the degree of impairment was similar for the two groups. As part of the study, information was presented 1 1/2 hours after the administration of the drugs; the subjects' ability to recall the information 24 hours later was impaired by both doses of triazolam, and the percent decrease was similar in the young and elderly groups. CONCLUSIONS. Triazolam caused a greater degree of sedation and greater impairment of psychomotor performance in healthy elderly persons than in young persons who received the same dose. These effects resulted from reduced clearance and higher plasma concentrations of triazolam rather than from an increased intrinsic sensitivity to the drug. On the basis of these results, the dosage of triazolam for elderly persons should be reduced on average by 50 percent. 相似文献
13.
G. Engelhardt D. Homma K. Schlegel R. Utzmann C. Schnitzler 《Inflammation research》1995,44(10):423-433
The anti-inflammatory, analgesic and antipyretic properties of the new non-steroidal anti-inflammatory agent, meloxicam, were investigated in a variety of animal models and compared with the properties of piroxicam, diclofenac, indomethacin and several other NSAIDs.With respect to the total effect of a single oral dose, the anti-exudative effect of meloxicam on carrageenaninduced oedema in the rat exceeded that of all the NSAIDs included in the comparison. Additionally, meloxicam showed the greatest potency of all the compounds examined with respect to adjuvant-induced arthritis in the rat, the granuloma pouch model and the cotton pellet test in the rat. Unlike indomethacin, in the carrageenan pleurisy model in the rat, meloxicam caused both a dose-dependent reduction in exudate volume and also inhibition of leucocyte migration.Meloxicam showed a strong and lasting effect on inflammatory pain in the rat. Like other NSAIDs, but unlike dipyrone, meloxicam had no effect in the hot plate and tail clamp tests, which are used to identify weak central analgesic effects. Unlike dipyrone and like indomethacin, meloxicam had no effect in a model of visceral distention pain.In common with other NSAIDs, meloxicam had no influence on the body temperature of normothermic rats in the anti-inflammatory dose range, but did reduce yeastinduced fever in the rat in a dose-dependent manner. Like piroxicam, meloxicam had a uricosuric effect on rats treated with oxonic acid.Low-dose meloxicam inhibited both bradykinin-induced and PAF-induced bronchospasm in the guinea-pig, but had no effect on acetylcholine-induced bronchospasm.Piroxicam had greater ulcerogenic effects in the rat stomach than meloxicam.The therapeutic range of meloxicam in the rat, with regard to inhibition of adjuvant arthritis, was several times greater than that of piroxicam, indomethacin, diclofenac and naproxen. 相似文献
14.
P Engelhardt 《Zeitschrift für Orthop?die und ihre Grenzgebiete》1990,128(3):262-265
In general, prophylactic treatment of the contralateral hip in manifest unilateral EFH is a well-proven and efficacious preventive measure. Shortly before the end of growth, however, due to asynchronous closure of the growth plate, the contralateral side may already be fused, so that there is no longer any danger of the hip slipping. Diagnostic difficulties in radiologic assessment of growth plate structure can be resolved with CT. In a two-year period, CT confirmation of closure of the growth plate enabled surgery on the contralateral side to be dispensed with in 3 cases (out of a total of 9). 相似文献
15.
16.
Cryotherapy is a therapeutic modality frequently used in the treatment of athletic injuries. In very rare circumstances, inappropriate use in some individuals can lead to nerve injury resulting in temporary or permanent disability of the athlete. Six cases of cold-induced peripheral nerve injury from 1988 to 1991 at the Sports Medicine Center at Duke University are reported. Although disability can be severe and can render an athlete unable to compete for several months, each of these cases resolved spontaneously. Whereas the application of this modality is typically quite safe and beneficial, clinicians must be aware of the location of major peripheral nerves, the thickness of the overlying subcutaneous fat, the method of application (with inherent or additional compression), the duration of tissue cooling, and the possible cryotherapy sensibility of some individuals. 相似文献
17.
At least two mutant alleles of ornithine delta-aminotransferase cause gyrate atrophy of the choroid and retina in Finns. 总被引:11,自引:1,他引:10
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G A Mitchell L C Brody I Sipila J E Looney C Wong J F Engelhardt A S Patel G Steel C Obie M Kaiser-Kupfer et al. 《Proceedings of the National Academy of Sciences of the United States of America》1989,86(1):197-201
Gyrate atrophy of the choroid and retina (GA) is an inherited chorioretinal degeneration caused by deficiency of ornithine delta-aminotransferase (OAT; L-ornithine: 2-oxo-acid aminotransferase; EC 2.6.1.13). GA is one of the "Finnish genetic diseases," a group of several rare monogenic disorders that occur with increased frequency in the Finnish population. Using a combination of RNase A protection, genomic cloning, and polymerase chain reaction amplification of genomic DNA, we found one of two missense mutant OAT alleles to be present in each of 16 Finnish GA pedigrees. The first mutation R180T, in which arginine-180 is replaced by threonine, was present in homozygous form in patients from two pedigrees. The second mutation L402P, in which leucine-402 is replaced by proline, was present in homozygous form in patients from 14 pedigrees. Neither mutation was present in 19 Finnish controls. L402P was not present in 18 non-Finnish GA patients but R180T was found in an American GA patient. We constructed full-length mutant cDNAs by amplifying patient cDNA with the polymerase chain reaction and cloning a restriction fragment containing the mutation into an otherwise normal human OAT cDNA. These mutant cDNAs were then expressed in CHO-K1 cells, which lack endogenous OAT. Both R180T and L402P inactivate OAT. These results show molecular heterogeneity in GA alleles even in the Finnish population. 相似文献
18.
Engelhardt HT 《The Hastings Center report》1989,19(1):S7-S9
The question is explored of whether the state may stop competent individuals from being voluntarily euthanatized, now that the state's power is justified by reason instead of divine right. The challenge of determining a moral and political agenda which reason would endorse is analyzed in relation to the philosophical question: who may effectively constrain others so as to impose a particular view of the good life and the good death? And why? The right to euthanasia is established negatively in a pluralist, secular society not because we agree that it is good, but because where there is no justification for state authority to intervene coercively, individuals are morally free to act. 相似文献
19.
D. Heuss A. Engelhardt H. Göbel B. Neundörfer H. Lochmüller 《Virchows Archiv : an international journal of pathology》1994,425(1):101-105
We report on the expression of growth associated protein (GAP)43 and neural cell adhesion molecule (NCAM) in congenital fibre type disproportion (CFTD) with myopathological additional signs of interstitial myositis. We assume that sarcolemmal GAP43 in developmental disordered myocytes plays a role in maintenance of growth morphology. In muscular dystrophy light microscopical evaluation reveals no GAP43 immunoreactivity in regenerating fibres. The expression of GAP43 seems to be a characteristic feature of CFTD. The expression of NCAM, particularly in the sarcolemma of small muscle fibres of CFTD, indicates a functional state of permanent partial denervation. Whether the steroid-responsive interstitial myositis is pathogenetically related to CFTD or a coincidental inflammation is not known. Because of the clinical and myopathological data the differential diagnosis of Emery-Dreifuss muscular dystrophy is considered. 相似文献
20.
ICAM-1, VCAM-1, and MAdCAM-1 are expressed on choroid plexus epithelium but not endothelium and mediate binding of lymphocytes in vitro. 总被引:4,自引:2,他引:4
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
B. J. Steffen G. Breier E. C. Butcher M. Schulz B. Engelhardt 《The American journal of pathology》1996,148(6):1819-1838
The expression of cell adhesion molecules (CAMs) in the choroid plexus was studied in normal brain and during experimental autoimmune encephalomyelitis (EAE) in the SJL/J mouse during inflammation induced by intracerebral injection of killed Corynebacterium parvum in the C3H/He mouse. Both ICAM-1 and VCAM-1, but not MAdCAM-1, were constitutively expressed on choroid plexus epithelium but not on the fenestrated capillary endothelial cells within the choroid plexus. During EAE, we observed an up-regulation of ICAM-1 and VCAM-1 and de novo expression of MAdCAM-1 on choroid plexus epithelial cells. In contrast, endothelial cells in the choroid plexus were not induced to express any of the investigated CAMs. In in situ hybridization analysis we demonstrated that ICAM-1, VCAM-1, and MAdCAM-1 were locally synthesized and that the amount of their mRNAs increased in the inflamed choroid plexus. In vitro, primary choroid plexus epithelial cells could be induced to express ICAM-1, VCAM-1, and MAdCAM-1 on their surface after treatment with proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1, interferon-gamma, and lipopolysaccharide. To investigate the functional status of the expressed CAMs we performed Stamper-Woodruff binding assays on frozen sections of inflamed and naive brains. ICAM-1, VCAM-1, and MAdCAM-1 expressed in choroid plexus epithelial cells mediated binding of lymphocytes via their known ligands LFA-1 and alpha4-integrin, respectively. The expression of ICAM-1, VCAM-1, and MAdCAM-1 on choroid plexus epithelial cells together with the lack of their expression on the fenestrated choroid plexus endothelium raises the possibility that the epithelial blood-cerebrospinal-fluid barrier plays an important role in the immunosurveillance of the central nervous system. 相似文献