全文获取类型
收费全文 | 16928篇 |
免费 | 913篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 222篇 |
儿科学 | 440篇 |
妇产科学 | 195篇 |
基础医学 | 2093篇 |
口腔科学 | 623篇 |
临床医学 | 1512篇 |
内科学 | 3230篇 |
皮肤病学 | 363篇 |
神经病学 | 1794篇 |
特种医学 | 1302篇 |
外国民族医学 | 1篇 |
外科学 | 2440篇 |
综合类 | 169篇 |
一般理论 | 4篇 |
预防医学 | 1485篇 |
眼科学 | 322篇 |
药学 | 801篇 |
1篇 | |
中国医学 | 14篇 |
肿瘤学 | 861篇 |
出版年
2021年 | 199篇 |
2020年 | 122篇 |
2019年 | 153篇 |
2018年 | 239篇 |
2017年 | 188篇 |
2016年 | 217篇 |
2015年 | 275篇 |
2014年 | 388篇 |
2013年 | 502篇 |
2012年 | 691篇 |
2011年 | 727篇 |
2010年 | 496篇 |
2009年 | 432篇 |
2008年 | 729篇 |
2007年 | 822篇 |
2006年 | 747篇 |
2005年 | 737篇 |
2004年 | 663篇 |
2003年 | 633篇 |
2002年 | 641篇 |
2001年 | 638篇 |
2000年 | 592篇 |
1999年 | 483篇 |
1998年 | 225篇 |
1997年 | 177篇 |
1996年 | 155篇 |
1995年 | 173篇 |
1994年 | 156篇 |
1993年 | 130篇 |
1992年 | 342篇 |
1991年 | 369篇 |
1990年 | 314篇 |
1989年 | 306篇 |
1988年 | 285篇 |
1987年 | 237篇 |
1986年 | 261篇 |
1985年 | 259篇 |
1984年 | 214篇 |
1983年 | 196篇 |
1982年 | 134篇 |
1981年 | 131篇 |
1980年 | 121篇 |
1979年 | 239篇 |
1978年 | 156篇 |
1977年 | 149篇 |
1975年 | 147篇 |
1974年 | 127篇 |
1973年 | 135篇 |
1972年 | 141篇 |
1970年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
P. Satz K. Zaucha D. L. Forney C. McCleary R. F. Asarnow R. Light H. Levin D. Kelly M. Bergsneider D. Hovda N. Martin M. J. Caron N. Namerow D. Becker 《Brain injury : [BI]》1998,12(7):555-567
Traumatic brain injury (TBI) subjects at Glasgow Outcome Scale levels 3 (severe disability), 4 (moderate disability), 5 (good recovery), and an other injury control group (OIC) were compared in terms of neuropsychological, psychosocial, and vocational functioning 6 months after injury. Subjects were a sample of 100 patients with a moderate to severe traumatic brain injury (TBI) and a matched sample of 30 other injury control subjects (OIC) enrolled in the UCLA Brain Injury Research Center study of TBI outcome. Overall, the results showed a systematic decrease in mean neuropsychological test performance as a function of increasing GOS severity, as well as an increased prevalence of symptoms of depression and lower ratings on measures assessing employability and capacity for self care. TBI patients in the 'severe' and 'moderate disability' groups were distinctly inferior to the 'good recovery' and 'OIC' groups, who were quite similar to each other in terms of cognitive, psychosocial, and vocational outcomes. The results demonstrate overall support for the predictive and concurrent validity of the GOS 6 months post injury. Despite these results, which strengthen the utility and appeal of the GOS for multicentre studies, concerns still remain regarding GOS category 4 (moderate disability), which was shown to lack sufficient discriminability in this study. 相似文献
102.
103.
A E Becker 《Wiener klinische Wochenschrift》1988,100(24):787-791
A distinction is made between heart muscle diseases with a known cause, or occurring as part of a systemic disease, and those of unknown cause. The first category is termed "specific heart muscle disease". The term "cardiomyopathy" is then limited to the latter category. Cardiomyopathies are categorized as dilated cardiomyopathy, hypertrophic cardiomyopathy and restrictive cardiomyopathy. The pathology of dilated cardiomyopathy depends on the clinical stage of the disease. Basically, the histology shows hypertrophic myocytes, often with degenerative signs, and interstitial fibrosis. Lymphocytes may be observed, particularly in cases studied shortly after the onset of symptoms. Endocardial thickening may occur in time. The role of endomyocardial biopsies in the clinical setting is limited and relates mainly to excluding other diseases, such as myocarditis. The pathology of hypertrophic cardiomyopathy is characterized by myocardial wall thickening, either asymmetric or symmetric, and disorganization of the normal myocardial texture. The latter phenomenon should be distinguished from disarray, since it may occur as a natural phenomenon. The differentiation between these two may be extremely difficult on the basis of only small tissue samples, as with endomyocardial biopsies. This, therefore, poses serious limitations in the use of endomyocardial biopsies. The pathology of restrictive cardiomyopathy also depends on the stage of the disease.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
104.
Adult-onset rod disease with abundant intranuclear rods 总被引:2,自引:0,他引:2
Summary The third case of adult-onset rod disease (nemaline myopathy) with abundant myofibrillar as well as intranuclear rods is described. The 61-year-old woman suffered from progressive weakness of proximal extremities and of the neck, mimicking polymyositis. Muscle biopsy revealed a striking myopathic pattern, with intranuclear rods occurring in 31% of the fibres. On light and electron microscopy and by immunohistochemical study, the rods differed from myofibrillar rods. The absence of -actinin in intranuclear rods suggests an enhanced readiness of actin filaments to bind to diverse proteins, instead of overproduction of -actinin as the pathogenetic basis of the rod formation. 相似文献
105.
Analysis of DNA adducts in putative premalignant hepatic nodules and nontarget tissues of rats during 2-acetylaminofluorene carcinogenesis 总被引:3,自引:0,他引:3
Exposure of rats to a standard four-cycle feeding regimen of 0.06% 2-acetylaminofluorene (AAF) results in the formation of putatively premalignant hepatic nodules, but the types and magnitude of DNA adducts formed in these nodules has not been previously examined. By using a sensitive 32P-adduct assay (R. C. Gupta, Cancer Res., 45: 5656-5662, 1985), we analyzed the DNA adduct lesions in individual hepatic nodules at various times during and after exposure to AAF. Kidney, spleen, and testis were included as nontarget tissues. No qualitative difference was observed in the DNA adducts found in hepatic nodules and nontarget tissues; however, quantitative differences occurred. At least one unknown and two known (dG-C8-AF and dG-N2-AAF) DNA adducts were detected, with dG-C8-AF being predominantly (96-98%) formed, in all tissues examined. At the end of the first three weeks of AAF feeding, the concentration of the deacetylated adduct dG-C8-AF in liver (223 fmol/micrograms DNA) was found to be about 2, 6, and 5 times higher than in kidney, spleen, and testis, respectively. The concentration of the N2-acetylated adduct in liver (4.5 fmol/micrograms DNA) was 4-fold higher than in kidney and strikingly higher (51- and 42-fold, respectively) than in spleen and testis. At the end of the fourth feeding cycle, total DNA adducts measured in the hepatic nodules ranged from 30-100 fmol/micrograms DNA, while the "surrounding liver," kidney, spleen, and testis showed 235, 218, 62, and 28 fmol adducts/micrograms DNA, respectively. Sixty days following the cessation of AAF, the binding in both the persistent nodules and liver had decreased to 7% of their respective levels measured at the end of the fourth cycle, while adducts in kidney, spleen, and testis were 32%, 18% and 19%. After 88 days, the binding levels in the nontarget tissues declined further, but no additional adduct removal occurred in the nodules. Our data indicate that (a) although the metabolic apparatus for activation of AAF is diminished in the hepatic nodules, a significant level of adduct formation occurs in the cells of this putative, premalignant lesion, and (b) unlike in the nontarget tissues, repair processes in the premalignant nodules may not be operative several weeks after the cessation of AAF exposure. 相似文献
106.
L Walters P Bartel D K Sommers P Becker 《Methods and findings in experimental and clinical pharmacology》1988,10(7):419-425
This study investigated central anticholinergic drug effects on: (1) the Randt Memory Test, a relatively new instrument which measures the acquisition and recall of verbal and pictorial information; (2) the averaged photopalpebral reflex (PPR), an electrophysiological parameter, the validity of which needs to be further investigated in pharmacological research and; (3) mood as measured by a 16-item visual analogue scale. Atropine (1 mg and 2 mg), pirenzepine (20 mg) and a placebo were administered intramuscularly in a double-blind cross-over trial in eight healthy volunteers. There were no inter-treatment differences on the Randt Memory Test. This finding is seemingly in contrast to those reported by some authors using other memory tests. In contrast to the reported effects of some benzodiazepines, the anticholinergics used in the present study did not prolong the latencies of the PPR, but reduced the amplitudes. Visual analogue scales indicated central effects for both pirenzepine and atropine. This implies pirenzepine's penetration of the blood-brain barrier and a physiological function for central muscarinic-1-receptors. The significant anticholinergic effects were exclusive to the "alertness" factor. 相似文献
107.
A relatively nonhygroscopic crystalline form of the glycopeptide, N-acetylmuramyl-L--aminobu-tyryl-D-isoglutamine (I), containing approximately one molecule of water was prepared from amorphous material. The crystalline material, consisting of a mixture of the and anomers, exhibited better physical and chemical stability than the lyophilized amorphous material. The /-anomer ratios of I in both the crystalline and the amorphous state were approximately equal but different from that in solution. 相似文献
108.
"Advertising" has become a very controversial topic, not just among dentists, but among all professionals. That controversy focuses on three questions. First, what are the legal issues surrounding dental advertising and how are these issues being resolved? Second, what are the attitudes toward advertising among practicing dentists and how are these attitudes changing? Finally, how many dentists advertise and what are those advertising dentists actually doing? The purpose of this paper is to neither praise nor excoriate advertising, but to refer to the law and to published research in order to provide dental practitioners with a broader understanding of this topic. 相似文献
109.
D E Becker 《Journal of the American Dental Association (1939)》1989,119(1):153-156
This review article illustrates that all medications used for conscious sedation can depress ventilation. The dental practitioner should not abandon the use of these agents to control fear and anxiety during dental treatment; rather, the dentist should administer the agents cautiously and monitor respiratory status throughout the dental procedure. In this regard, pulse oximetry is a welcomed advance in monitoring as it acts to warn the unknowing clinician that he is approaching a "cliff" (the steep portion of the oxyhemoglobin curve). 相似文献
110.