全文获取类型
收费全文 | 16602篇 |
免费 | 1171篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 182篇 |
儿科学 | 422篇 |
妇产科学 | 371篇 |
基础医学 | 2137篇 |
口腔科学 | 415篇 |
临床医学 | 1790篇 |
内科学 | 3362篇 |
皮肤病学 | 192篇 |
神经病学 | 1753篇 |
特种医学 | 549篇 |
外国民族医学 | 5篇 |
外科学 | 2849篇 |
综合类 | 204篇 |
一般理论 | 17篇 |
预防医学 | 1310篇 |
眼科学 | 409篇 |
药学 | 843篇 |
1篇 | |
中国医学 | 40篇 |
肿瘤学 | 975篇 |
出版年
2022年 | 130篇 |
2021年 | 261篇 |
2020年 | 175篇 |
2019年 | 272篇 |
2018年 | 343篇 |
2017年 | 268篇 |
2016年 | 303篇 |
2015年 | 291篇 |
2014年 | 430篇 |
2013年 | 687篇 |
2012年 | 902篇 |
2011年 | 1004篇 |
2010年 | 657篇 |
2009年 | 562篇 |
2008年 | 927篇 |
2007年 | 1033篇 |
2006年 | 1014篇 |
2005年 | 982篇 |
2004年 | 1009篇 |
2003年 | 952篇 |
2002年 | 906篇 |
2001年 | 201篇 |
2000年 | 159篇 |
1999年 | 202篇 |
1998年 | 179篇 |
1997年 | 173篇 |
1996年 | 146篇 |
1995年 | 150篇 |
1994年 | 118篇 |
1993年 | 109篇 |
1992年 | 143篇 |
1991年 | 132篇 |
1990年 | 115篇 |
1989年 | 107篇 |
1988年 | 97篇 |
1987年 | 108篇 |
1986年 | 96篇 |
1985年 | 105篇 |
1984年 | 129篇 |
1983年 | 119篇 |
1982年 | 137篇 |
1981年 | 123篇 |
1980年 | 133篇 |
1979年 | 91篇 |
1978年 | 86篇 |
1977年 | 87篇 |
1976年 | 95篇 |
1975年 | 73篇 |
1974年 | 72篇 |
1973年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Lead poisoning in six captive avian species 总被引:2,自引:0,他引:2
W. Nelson Beyer James W. Spann Louis Sileo J. Christian Franson 《Archives of environmental contamination and toxicology》1988,17(1):121-130
Red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), mallards (Anas platyrhynchos), northern bobwhites (Colinus virginianus), and eastern screech-owls (Otus asio) were poisoned with a concentration of lead (Pb) acetate in the diet which was increased by 60% each week until half of the birds in each treatment group died; surviving birds and all control birds except screech-owis were then killed by euthanasia. An additional group of mallards was poisoned with Pb shot. The gizzards of mallards poisoned either way usually were stained with bile; some of these birds also had proventricular impaction. Most poisoned birds of the other species were emaciated but lacked other gross lesions caused by Pb poisoning. In birds other than mallards, Pb poisoning could not be diagnosed without histological or hematological examinations or analysis of tissues. Poisoned birds of all six species could be reliably separated from control birds by an increase in the protoporphyrin concentrations in the blood and by a decrease in the activity of delta-aminolevulinic acid dehydratase (ALAD) in red blood cells. Hepatic iron (Fe) concentrations varied so much among individual birds that even though median hepatic Fe concentrations increased in poisoned birds, hepatic Fe concentrations were not useful in identifying poisoned birds. Renal intranuclear inclusion bodies occurred in 83% of all birds dying from Pb poisoning. Nephrosis, myocardial necrosis, and arterial fibrinoid necrosis were occasionally present. Median hepatic Pb concentrations varied from 20 ppm (wet wt) in male red-winged blackbirds to 111 ppm in female northern bobwhites. Median renal Pb concentrations varied from 22 ppm in redwinged blackbirds to 190 ppm in female northern bobwhites. Hepatic and renal Pb concentrations varied substantially among birds within each species. Median hepatic and renal Pb concentrations of birds that died were not statistically different (p > 0.05) from those of birds that were killed. Lead shot and Pb acetate affected mallards similarly. 相似文献
72.
73.
Tadpole and adult Xenopus, manipulated to be of comparable size, exhibited stagespecific
antibody expression. The production of adult-type higher-affinity anti-DNP
antibodies proved to be independent of the age and size of the individual and is
concomitant with the completion of metamorphosis. The appearance of new antibody
specificities at such a time suggests that their expression occurs with the cell turnover
and renewal during a period of morphological changes. 相似文献
74.
75.
RO 15-1788, a specific benzodiazepine antagonist, although it effectively antagonizes the clinical effects of benzodiazepines (i.e., sedation and amnesia), can also induce subjective agonist effects such as sedation or inverse agonist effects such as anxiety. The purpose of this study was to investigate in seven healthy volunteers the effect of RO 15-1788 on cerebral blood flow when intravenously injected alone or with midazolam and to compare its effects with midazolam administered alone. Cerebral blood flow was measured with the 133xenon inhalation technique and the drugs were administered simultaneously in a double-blind, randomized fashion during the four following sessions: placebo-placebo; midazolam-placebo; RO 15-1788-placebo; midazolam-RO 15-1788. No difference in cerebral blood flow was noted between the placebo-placebo, the RO 15-1788-placebo, and the RO 15-1788-midazolam sessions--although midazolam injected alone decreased cerebral blood flow by 30%. The sedation, amnesia, and the electroencephalograph (EEG) and muscle tone changes observed with midazolam-placebo were not present during the RO 15-1788-placebo and RO 15-1788-midazolam sessions. This study demonstrates the absence of effects of RO 15-1788 on cerebral blood flow when injected alone and the efficacy of this new drug in antagonizing the depressant effects of midazolam on cerebral hemodynamics. 相似文献
76.
Yancu Hertzanu M.D. Menachem Hirsch Louis Goleman 《Cardiovascular and interventional radiology》1987,10(4):230-233
Two unusual cases of delayed synthetic graft complications resulting from manufacturing defects of knitted Dacron are presented.
Computed tomography appears to be a suitable noninvasive alternative examination to angiography in this condition. 相似文献
77.
Lysia S. Forno J. William Langston Louis E. DeLanney Ian Irwin George A. Ricaurte 《Annals of neurology》1986,20(4):449-455
Systemic administration of the recently discovered neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces severe clinical parkinsonism and degeneration of the substantia nigra in humans and monkeys. In previous studies, no convincing structural damage to nerve cells outside the substantia nigra could be demonstrated in subhuman primates. Using a protracted MPTP regimen and older animals, we now report locus ceruleus lesions and eosinophilic inclusion bodies in squirrel monkeys. The inclusions were seen only in areas where Lewy bodies are found in human Parkinson's disease. No such abnormalities were seen in control animals. These findings suggest that similarities between the neuropathology of MPTP-induced parkinsonism in the monkey and human Parkinson's disease are greater than first thought and increase the usefulness of the MPTP monkey model for research in Parkinson's disease. 相似文献
78.
A spontaneous lymphoid thymus tumor was discovered in a male Xenopus of the MHC
ff genotype. The tumor cell can be transplanted in histocompatible larval ff hosts, but not
in ff adults unless irradiated (3000 rad). The tumor is rejected by allogeneic hosts. The
tumor cells express neither markers of the B-cell lineage nor MHC encoded molecules;
they express only markers of the T-cell lineage. Its lymphoid population is clonal as
revealed by the existence of a stable rearrangement pattern of the immunoglobulin
genes. Cell lines growing continuously in vitro have been derived from the tumor. 相似文献
79.
80.
Wilfred C. G. Peh F.R.C.R. Louis A. Gilula M.D. Max R. Kasselt M.D. 《Emergency radiology》1997,4(4):255-257
Automobile air bag inflation-caused injuries to the chest, neck, and face, in particular the orbital contents, are infrequent but recognized. We report the occurrence of multiple digital fractures in the left hand of a 30-yearold male driver as a result of sudden air bag inflation. Continued monitoring of the potential hazards of this device is suggested. 相似文献