全文获取类型
收费全文 | 1153篇 |
免费 | 161篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 29篇 |
妇产科学 | 13篇 |
基础医学 | 232篇 |
口腔科学 | 6篇 |
临床医学 | 82篇 |
内科学 | 178篇 |
皮肤病学 | 4篇 |
神经病学 | 138篇 |
特种医学 | 99篇 |
外科学 | 194篇 |
综合类 | 29篇 |
预防医学 | 66篇 |
眼科学 | 7篇 |
药学 | 63篇 |
1篇 | |
肿瘤学 | 167篇 |
出版年
2021年 | 9篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 32篇 |
2012年 | 49篇 |
2011年 | 25篇 |
2010年 | 19篇 |
2009年 | 41篇 |
2008年 | 45篇 |
2007年 | 47篇 |
2006年 | 42篇 |
2005年 | 60篇 |
2004年 | 51篇 |
2003年 | 58篇 |
2002年 | 37篇 |
2001年 | 48篇 |
2000年 | 64篇 |
1999年 | 40篇 |
1998年 | 36篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 15篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 29篇 |
1991年 | 27篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 28篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 23篇 |
1979年 | 17篇 |
1978年 | 13篇 |
1977年 | 16篇 |
1976年 | 19篇 |
1975年 | 18篇 |
1974年 | 13篇 |
1973年 | 22篇 |
1972年 | 17篇 |
1968年 | 7篇 |
排序方式: 共有1333条查询结果,搜索用时 15 毫秒
1.
2.
Spectrum of pulmonary nontuberculous mycobacterial infection 总被引:5,自引:0,他引:5
3.
4.
P. M. Bourgouin D. Tampieri W. Johnston J. Steward D. Melançon R. Ethier 《Neuroradiology》1992,34(2):110-111
Summary We report a patient with multiple angiographically occult vascular malformations in the brain and spine. Magnetic resonance imaging showed multiple lesions in brain and spine with hypointense areas on both T1 and T2-weighted images. These hypointense areas are usually secondary to hemosiderin deposits consistent with remote bleeding in the lesions. We conclude that when magnetic resonance reveals an intraspinal lesion with signal intensity characteristics consistent with a vascular malformation, an examination of the brain should be performed to rule out associated intracranial lesions. The finding of multiple lesions in the brain with identical signal intensity characteristics reinforces the diagnosis of vascular malformation. 相似文献
5.
O Steward 《Hippocampus》1992,2(3):247-268
This study evaluates whether three forms of sprouting occur in the hippocampus of the cat following unilateral entorhinal cortex (EC) lesions: (1) sprouting of projections from the EC contralateral to the lesion; (2) sprouting of the commissural/associational system; and (3) sprouting of mossy fibers. Tract tracing techniques were used to define the normal organization of the entorhinal cortical projection system, the commissural/associational (C/A) systems, and the mossy fiber projections in normal cats. The same techniques were then used to evaluate whether there were changes in these projections in animals with long-standing unilateral EC lesions. The projections from the entorhinal cortex were evaluated autoradiographically following injections of 3H proline into the entorhinal area. The projections of the C/A system were traced using the Fink-Heimer technique after lesions of the hippocampal commissures, and by using autoradiographic techniques after injections of 3H proline into the hippocampus. The distribution of mossy fibers was evaluated using the Timm's stain. The results reveal that unilateral lesions of the EC in cats lead to the same sorts of sprouting that have been described in rats. There is: (1) an increase in the density of the crossed projection from the surviving EC to the contralateral dentate gyrus that had been deprived of its normal EC inputs; (2) an expansion of the terminal field of the C/A projection system into portions of the molecular layer of the dentate gyrus normally occupied by EC projections; and (3) an increase in supragranular mossy fibers in some animals. The mossy fiber sprouting was especially prominent when the lesions encroached upon the hippocampus. The studies also reveal additional details about the normal organization of hippocampal pathways in cats. The most important points are: (1) there is a crossed projection from the entorhinal cortex to the contralateral dentate gyrus; and (2) there is a complex laminar organization of the commissural and associational terminal fields in the molecular layer of the dentate gyrus that appears to be related to the point of origin of the projections along the septotemporal axis of the hippocampus. This heretofore unrecognized aspect of the laminar organization of C/A terminations has important implications for the temporal competition hypothesis, which has been advanced to account for the development of these afferent systems. 相似文献
6.
Alex Steward 《American journal of surgery》1943,59(3):598-600
7.
The influence of epitope density on the estimation of the affinity of antibody for complex antigens. 总被引:1,自引:0,他引:1
The influence of the epitope density of the antigen on antibody affinity values determined by fluid- and solid-phase immunoassays was assessed. The affinity of the interaction of a panel of monoclonal anti-DNP antibodies of different affinities (as determined by equilibrium dialysis) for DNP-protein conjugates of various hapten substitution ratios was used as the test system. The results obtained showed that the epitope density of the antigen markedly influences the observed affinity values obtained by both experimental approaches. However, the monoclonal antibodies were ranked in affinity terms by both assays in a similar order to that given by equilibrium dialysis. It is concluded that provided due care is exercised in choosing an appropriate epitope density for the test antigen, these methods can be used to provide rapid estimations of average antibody affinities. 相似文献
8.
9.
W P Steward D Crowther L J McWilliam J M Jones D P Deakin I D Todd G Blackledge J Wagstaff J H Scarffe M Harris 《Cancer》1988,61(3):441-447
One hundred sixty-two patients with Stages III and IV non-Hodgkin's lymphoma of low-grade histologic type were treated with combination chemotherapy using cyclophosphamide, vincristine, and prednisolone (CVP) followed by radiotherapy to sites of previous bulk disease. The patients were randomized to receive either follow-up alone or "maintenance" chemotherapy with 2 years of intermittent chlorambucil. A complete remission was obtained in 56% of patients and the median survival was 64 months (median follow-up, 74 months). Multivariate analysis revealed stage (P less than 0.0001) and Karnofsky performance status (P = 0.021) to predict complete response (CR) and the achievement of a CR (P less than 0.0001), female sex (P = 0.008), the absence of bulk disease (P = 0.038) and low serum alkaline phosphatase (P = 0.002) to predict prolonged survival. The median relapse-free survival (RFS) of the complete responders was 41 months. A prolonged RFS was predicted by low stage (P = 0.014), low serum lactic dehydrogenase (LDH) (P = 0.045) levels, and by the administration of maintenance chlorambucil (P = 0.045). A prolonged survival of the complete responders was predicted by a low number of nodal sites of involvement with lymphoma at presentation (P = 0.022) and lack of liver involvement (P = 0.011). The administration of oral maintenance therapy with chlorambucil for a full 2 years was only possible in 38% of patients, mainly because of progression of disease and the induction of thrombocytopaenia, but despite this it prolonged the median RFS by 38 months and its use could be considered when future studies are being designed. 相似文献
10.
Localization of a gene for otosclerosis to chromosome 15q25-q26 总被引:5,自引:0,他引:5
Tomek MS; Brown MR; Mani SR; Ramesh A; Srisailapathy CR; Coucke P; Zbar RI; Bell AM; McGuirt WT; Fukushima K; Willems PJ; Van Camp G; Smith RJ 《Human molecular genetics》1998,7(2):285-290
Among white adults otosclerosis is the single most common cause of hearing
impairment. Although the genetics of this disease are controversial, the
majority of studies indicate autosomal dominant inheritance with reduced
penetrance. We studied a large multi- generational family in which
otosclerosis has been inherited in an autosomal dominant pattern. Five of16
affected persons have surgically confirmed otosclerosis; the remaining nine
have a conductive hearing loss but have not undergone corrective surgery.
To locate the disease- causing gene we completed genetic linkage analysis
using short tandem repeat polymorphisms (STRPs) distributed over the entire
genome. Multipoint linkage analysis showed that only one genomic region, on
chromosome 15q, generated a lod score >2.0. Additional STRPs were typed
in this area, resulting in a lod score of 3.4. STRPs FES (centromeric) and
D15S657 (telomeric) flank the 14. 5 cM region that contains an otosclerosis
gene.
相似文献