全文获取类型
收费全文 | 6569篇 |
免费 | 573篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 254篇 |
妇产科学 | 129篇 |
基础医学 | 885篇 |
口腔科学 | 149篇 |
临床医学 | 668篇 |
内科学 | 1494篇 |
皮肤病学 | 259篇 |
神经病学 | 464篇 |
特种医学 | 394篇 |
外国民族医学 | 3篇 |
外科学 | 930篇 |
综合类 | 66篇 |
预防医学 | 468篇 |
眼科学 | 126篇 |
药学 | 432篇 |
1篇 | |
中国医学 | 20篇 |
肿瘤学 | 350篇 |
出版年
2023年 | 31篇 |
2022年 | 62篇 |
2021年 | 167篇 |
2020年 | 131篇 |
2019年 | 190篇 |
2018年 | 215篇 |
2017年 | 158篇 |
2016年 | 172篇 |
2015年 | 171篇 |
2014年 | 214篇 |
2013年 | 261篇 |
2012年 | 371篇 |
2011年 | 371篇 |
2010年 | 248篇 |
2009年 | 225篇 |
2008年 | 309篇 |
2007年 | 264篇 |
2006年 | 284篇 |
2005年 | 257篇 |
2004年 | 197篇 |
2003年 | 206篇 |
2002年 | 189篇 |
2001年 | 178篇 |
2000年 | 157篇 |
1999年 | 145篇 |
1998年 | 125篇 |
1997年 | 131篇 |
1996年 | 135篇 |
1995年 | 99篇 |
1994年 | 98篇 |
1993年 | 84篇 |
1992年 | 156篇 |
1991年 | 135篇 |
1990年 | 90篇 |
1989年 | 102篇 |
1988年 | 94篇 |
1987年 | 92篇 |
1986年 | 87篇 |
1985年 | 94篇 |
1984年 | 60篇 |
1983年 | 49篇 |
1982年 | 44篇 |
1981年 | 38篇 |
1980年 | 20篇 |
1979年 | 22篇 |
1978年 | 31篇 |
1976年 | 27篇 |
1974年 | 19篇 |
1970年 | 17篇 |
1969年 | 23篇 |
排序方式: 共有7161条查询结果,搜索用时 703 毫秒
81.
André C Perrin-Fayolle M Grosclaude M Couturier P Basset D Cornillon J Piperno D Girodet B Sanchez R Vallon C Bellier P Nasr M 《International archives of allergy and immunology》2003,131(2):111-118
BACKGROUND: There is a growing consensus on the benefits of sublingual-swallow immunotherapy in the treatment of allergic diseases. METHODS: This randomized, double-blind placebo-controlled study was undertaken to assess the efficacy and safety of sublingual immunotherapy with standardized ragweed pollen extract tablets, in patients with an allergic rhinitis. A total of 110 outpatients were randomized (immunotherapy [I]: 55; placebo [P]: 55), of whom 99 were analyzable for efficacy (I: 48; P: 51) and 106 analyzable for safety (I: 53; P: 53). After a 28-day progression phase, the patients received a maintenance treatment during 6.5 months. Efficacy variables included a global assessment of efficacy (patient/ investigator), symptoms and medication scores as well as the frequency of asthma attacks. RESULTS: In the active treatment group, 43 patients completed the study, versus 49 on placebo. During the whole period of pollination, the difference favoring immunotherapy was highly significant for the global assessment by the patient (p = 0.004) and by the investigator (p = 0.005). Adverse reactions were reported more often in the active treatment but mild or moderate, and they abated after dose adjustment. A subgroup analysis of those patients receiving the highest dose of immunotherapy (3 tablets 3 times a week) showed a highly significant response for rhinitis and conjunctivitis total scores by comparison to lower dosages. CONCLUSION: This study confirms the efficacy and safety of sublingual immunotherapy and strongly suggests a dose-response relationship. 相似文献
82.
L1 knockout mice show dilated ventricles, vermis hypoplasia and impaired exploration patterns 总被引:8,自引:3,他引:8
Fransen E; D'Hooge R; Van Camp G; Verhoye M; Sijbers J; Reyniers E; Soriano P; Kamiguchi H; Willemsen R; Koekkoek SK; De Zeeuw CI; De Deyn PP; Van der Linden A; Lemmon V; Kooy RF; Willems PJ 《Human molecular genetics》1998,7(6):999-1009
L1 is a neural cell adhesion molecule mainly involved in axon guidance and
neuronal migration during brain development. Mutations in the human L1 gene
give rise to a complex clinical picture, with mental retardation,
neurologic abnormalities and a variable degree of hydrocephalus. Recently,
a transgenic mouse model with a targeted null mutation in the L1 gene was
generated. These knockout (KO) mice show hypoplasia of the corticospinal
tract. Here we have performed further studies of these KO mice including
magnetic resonance imaging of the brain, neuropathological analysis and
behavioral testing. The ventricular system was shown to be abnormal with
dilatation of the lateral ventricles and the 4th ventricle, and an altered
shape of the Sylvius aqueduct. Additionally, the cerebellar vermis of the
KO mice is hypoplastic. Their exploratory behavior is characterized by
stereotype peripheral circling reminiscent of that of rodents with induced
cerebellar lesions.
相似文献
83.
84.
Anthony J McGoron Michael Capille Michael F Georgiou Pablo Sanchez Juan Solano Manuel Gonzalez-Brito John W Kuluz 《BMC medical imaging》2008,8(1):4
Background
Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. 相似文献85.
PJ Hallam P. Mannucci A. Tripodi D. Bevan B. Lawsen L. Tengborn A. Wacey DN Coopel 《Clinical genetics》1998,54(3):231-233
Hallam PJ, Mannucci P, Tripodi A, Bevan D, Laursen B, Tengborn L, Wacey A, Cooper DN. Three novel PROC gene lesions causing protein C deficiency. Clin Genet 1998: 54: 231–233. 0 Munksgaard, 1998
Missense mutations. three of them novel (Am210→Val, Asn248→ Ile, Ah355→Val), were found in the protein c ( PROC ) genes of 7 patients with inherited protein C deficiency associated with venous thrombosis. Comparison with the phenotypic effects of mutations in the analogous residues of factor IX causing hdernophilia B and the use of molecular modelling has provided explanations as to how these lesions might alter either the structure, function or secretion of the protein C molecules encoded. 相似文献
Missense mutations. three of them novel (Am210→Val, Asn248→ Ile, Ah355→Val), were found in the protein c ( PROC ) genes of 7 patients with inherited protein C deficiency associated with venous thrombosis. Comparison with the phenotypic effects of mutations in the analogous residues of factor IX causing hdernophilia B and the use of molecular modelling has provided explanations as to how these lesions might alter either the structure, function or secretion of the protein C molecules encoded. 相似文献
86.
To gain insights into the composition of the B cell repertoire, we have investigated VH gene family expression associated with individual light chains. For this purpose, we have examined the use of 12 VH gene families in a large collection of hybridomas expressing one of the four lambda light chains [lambda 1 (V1J1), lambda 2 (V2J2 and V x J2) and lambda 3 (V1J3)]. Our results show that the distribution of the VH families is very different from one lambda subtype to another. This suggests that a few substitutions between VL regions are sufficient to generate very different associated repertoires by strong selection mechanisms. Moreover, we assume that the global VH expression pattern is not random but rather composed of many preferential VH/VL associations. 相似文献
87.
J Benitez C Martinez Frejo C Toledo J Sanchez Fayos C Ramos 《Cancer Genetics and Cytogenetics》1987,26(2):199-207
Serial cytogenetic studies have been performed in four patients with myelodysplastic syndromes. In all four a 5q- alteration was present, but with a different pattern of presentation. One patient presented 5q- as the only alteration since diagnosis; two patients acquired this alteration during the course of the disease; and the fourth showed a 5q- plus other alterations since the first cytogenetic study. Likewise, three of the four patients showed a clone with trisomy 8 and without 5q-. According to these observations and others from the literature with similar cytogenetic behavior, we have analyzed the following points: 5q- as a primary event and as the only alteration, 5q- as a secondary event, 5q- plus other alterations, and presence of cytogenetically different clones. Analysis of these points suggests that the 5q- alteration can represent an early mutation conferring a slow capacity of expansion to the affected clones, with the possibility of cytogenetic evolution during the progression of the disease (about 30% of the patients). Likewise, the association of trisomy 8 clones with 5q- clones can be a nonrandom event. 相似文献
88.
89.
Henriques C Sanchez MA Tryon R Landfear SM 《Molecular and biochemical parasitology》2003,130(2):101-110
African trypanosomes are unable to synthesize purines and depend upon purine nucleoside and nucleobase transporters to salvage these compounds from their hosts. To understand the crucial role of purine salvage in the survival of these parasites, a central objective is to identify and characterize all of the purine permeases that mediate uptake of these essential nutrients. We have cloned and functionally expressed in a purine nucleobase transport deficient strain of Saccharomyces cerevisiae a novel nucleobase transporter gene, TbNT8.1, from Trypanosoma brucei. The permease encoded by this gene mediates the uptake of hypoxanthine, adenine, guanine, and xanthine with Kms in the low micromolar range. The TbNT8.1 protein is a member of the equilibrative nucleoside transporter (ENT) family of permeases that occur in organisms as diverse as protozoa and mammals. TbNT8.1 is distinct from other ENT permeases that have been identified in trypanosomes in utilizing multiple purine nucleobases, rather than purine nucleosides, as substrates and is hence the first bona fide nucleobase permease identified in these parasites. Furthermore, unlike the mRNAs for other purine transporters, TbNT8.1 mRNA is significantly more abundant in insect stage procyclic forms than in mammalian stage bloodstream forms, and the TbNT8.1 permease thus may represent a major route for purine nucleobase uptake in procyclic trypanosomes. 相似文献
90.
E G Sanchez 《Southern medical journal》1987,80(2):223-227
The DSM-III diagnostic criteria for schizophreniform disorder, mainly based on duration of symptoms, are insufficient to furnish a good treatment strategy. In recent literature, schizophreniform disorder has been grouped either with the schizophrenias or with the affective disorders. Scandinavian researchers have described two other groups of psychotic disorders that resemble schizophreniform disorder. These are the reactive psychosis and the cycloid psychosis. They were found to be different from the schizophrenias and the affective disorders. "Good prognosis" schizophrenia, which has been extensively studied and reported in the literature, is clinically very similar to schizophreniform disorder. The relatively consistent data collected in patients with good prognosis schizophrenia may provide the basis for the additional diagnostic criteria needed in DSM-III schizophreniform disorder. 相似文献