全文获取类型
收费全文 | 321293篇 |
免费 | 16248篇 |
国内免费 | 700篇 |
专业分类
耳鼻咽喉 | 4232篇 |
儿科学 | 9399篇 |
妇产科学 | 7007篇 |
基础医学 | 45438篇 |
口腔科学 | 8349篇 |
临床医学 | 25329篇 |
内科学 | 72116篇 |
皮肤病学 | 8249篇 |
神经病学 | 29022篇 |
特种医学 | 9821篇 |
外国民族医学 | 106篇 |
外科学 | 40297篇 |
综合类 | 1485篇 |
一般理论 | 94篇 |
预防医学 | 29446篇 |
眼科学 | 6133篇 |
药学 | 22442篇 |
中国医学 | 981篇 |
肿瘤学 | 18295篇 |
出版年
2023年 | 1698篇 |
2022年 | 1806篇 |
2021年 | 5589篇 |
2020年 | 3208篇 |
2019年 | 5708篇 |
2018年 | 11021篇 |
2017年 | 7130篇 |
2016年 | 6677篇 |
2015年 | 7627篇 |
2014年 | 8581篇 |
2013年 | 13191篇 |
2012年 | 22198篇 |
2011年 | 22272篇 |
2010年 | 11439篇 |
2009年 | 9006篇 |
2008年 | 19101篇 |
2007年 | 20193篇 |
2006年 | 19022篇 |
2005年 | 18781篇 |
2004年 | 17511篇 |
2003年 | 16084篇 |
2002年 | 15212篇 |
2001年 | 8171篇 |
2000年 | 8739篇 |
1999年 | 7084篇 |
1998年 | 1555篇 |
1997年 | 1230篇 |
1996年 | 1145篇 |
1995年 | 1044篇 |
1994年 | 901篇 |
1992年 | 3690篇 |
1991年 | 3274篇 |
1990年 | 3105篇 |
1989年 | 2854篇 |
1988年 | 2645篇 |
1987年 | 2497篇 |
1986年 | 2352篇 |
1985年 | 2144篇 |
1984年 | 1640篇 |
1983年 | 1371篇 |
1979年 | 1379篇 |
1978年 | 1003篇 |
1977年 | 926篇 |
1975年 | 932篇 |
1974年 | 1125篇 |
1973年 | 1134篇 |
1972年 | 1045篇 |
1971年 | 1033篇 |
1970年 | 955篇 |
1969年 | 988篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A critical assessment of allergen component-based in vitro diagnosis in cherry allergy across Europe
A. Reuter J. Lidholm K. Andersson J. Östling M. Lundberg S. Scheurer E. Enrique A. Cistero-Bahima M. San Miguel-Moncin B. K. Ballmer-Weber Stefan Vieths 《Clinical and experimental allergy》2006,36(6):815-823
BACKGROUND: Food allergy to cherry occurs throughout Europe, typically with restricted oral reactions in the central and northern parts but with frequent systemic reactions in the Mediterranean region. Previous studies have demonstrated insufficient sensitivity of commercially available cherry extract reagents in the diagnosis of cherry allergy. OBJECTIVE: To assess the diagnostic performance of specific IgE tests based on recombinant cherry allergens in comparison with an extract-based assay and to skin prick test (SPT). A secondary objective was to analyse the frequency of systemic reactions in cherry-allergic subjects across Europe, including the largest population of LTP-sensitized subjects from central Europe studied to date. METHODS: A total of 186 subjects from central Europe and Spain were studied. Serum IgE was analysed with ImmunoCAP tests carrying rPru av 1, 3 and 4, combined and separately, and cherry extract. RESULTS: Among the central European cherry allergics, the mix of rPru av 1, 3 and 4 had a sensitivity of 95%, compared with 65% for cherry extract, and the IgE binding capacity of the recombinant mix was considerably higher. The sensitivity of the two tests was more comparable in the Spanish population, 95% and 86%, respectively. The recombinant allergen ImmunoCAP equalled SPT in terms of sensitivity and specificity. Consistent with previous reports, major geographic differences in sensitization pattern and prevalence of systemic reactions were found. A significantly higher rate of systemic reactions was found in Spanish patients sensitized to Pru av 3 whereas German patients sensitized to LTP only had oral allergy syndrome. CONCLUSIONS: The recombinant cherry allergen ImmunoCAP is a highly sensitive diagnostic tool, clearly superior to any diagnostic method based on cherry extract. Three cherry allergens are sufficient for detecting sensitization in 95% of cherry-allergic subjects. Systemic reactions are common in LTP-sensitized individuals but seem to require at least one additional causative factor. 相似文献
992.
993.
Jean-Fran?ois Ghersi-Egea Nathalie Strazielle Audrey Murat Anne Jouvet Annie Buénerd Marie-Fran?oise Belin 《Journal of cerebral blood flow and metabolism》2006,26(9):1165-1175
The choroid plexuses (CPs) form a protective interface between the blood and the ventricular cerebrospinal fluid (CSF). To probe into the pathways by which CPs provide brain protection, we sought to evaluate the efficiency of glutathione conjugation in this barrier as a mechanism to prevent the entry of blood-borne electrophilic, potentially toxic compounds into the CSF, and we investigated the fate of the resulting metabolites. Rat CPs, as well as human CPs from both fetal and adult brains, displayed high glutathione-S-transferase activities. Using an in vitro model of the blood-CSF barrier consisting of choroidal epithelial cells cultured in a two-chambered device, we showed that glutathione conjugation can efficiently prevent the entry of 1-chloro-2,4-dinitrobenzene (CDNB) into the CSF, a model for electrophilic compounds. The duration of this enzymatic protection was set by the concentration of CDNB to which the epithelium was exposed, and this barrier effect was impaired only on severe epithelial intracellular glutathione and cysteine depletion. The conjugate was excreted from the choroidal cells in a polarized manner, mostly at the blood-facing membrane, via a high-capacity transport process, which is not a rate-limiting step in this detoxification pathway, and which may involve transporters of the ATP-binding cassette c(Abcc) and/or solute carrier 21 (Slc21) families. Supplying the choroidal epithelium at the blood-facing membrane with a therapeutically relevant concentration of N-acetylcysteine sustained this neuroprotective effect. Thus, glutathione conjugation at the CP epithelium coupled with the basolateral efflux of the resulting metabolites form an efficient blood-CSF enzymatic barrier, which can be enhanced by pharmacologically increasing glutathione synthesis within the epithelial cells. 相似文献
994.
Antonio Z Gimeno‐García Adolfo Parra‐Blanco David Nicols‐Prez Cipriano Manzano‐Sanz Rafael Mndez‐Medina Enrique Quintero 《Digestive endoscopy》2006,18(2):144-146
Gastric mucormycosis involvement is a rare condition that usually occurs in inmunocompromised patients and frequently has a fatal outcome. We report the case of a 73‐year‐old woman admitted to the intensive care unit with severe bleeding after an acute pulmonary disease. Upper endoscopy disclosed wide and deep necrotic ulcers in the body and fundus of the stomach and greenish exudates with the antrum and the duodenum undamaged. Autopsy revealed an invasive mucormycosis and a severe atheromatosis. Several predisposing factors for mucormycosis infection have been reported until now. We postulate that ischemic gastritis could be a predisposing factor for colonization of zygomycete. 相似文献
995.
Objective To describe the different imaging modalities used for the diagnosis and classification of hydrocephalus, their role in defining
the optimal treatment of hydrocephalus and to define the optimal preoperative diagnostics for endoscopic third ventriculocisternostomy
(ETV).
Methods An overview on available imaging modalities for hydrocephalus will be given and their pros and cons discussed. In addition,
different aspects of the treatment of hydrocephalus by shunts and by ETV will be highlighted.
Discussion The role of the technical aspects of performing an ETV, the role of the surgeon’s philosophy, the role of the urgency of the
procedure, and the role of informed consent on the requirements for the imaging of the hydrocephalus will be discussed.
Conclusion The authors conclude that MRI is a conditio sine qua non for ETV in elective surgical cases. 相似文献
996.
997.
998.
BACKGROUND/AIMS: Hepatocytes (HEP) have been the major target for structural quantification in the liver, but an estimation of their total number (N), their percentage in relation to the global number of liver cells and the evaluation of the percentage of binucleated hepatocytes (BnHEPs) have never been performed with modern design-based stereological techniques. The establishment of sound technical guidelines and baseline quantitative data in non-pathological conditions are relevant to properly evaluate HEP hyperplasia and BnHEP responses. METHODS: In this study, we combined immunocytochemistry with sound design-based stereology for estimating the N of HEP and the N of non-hepatocytic cells (NHCs). For obtaining systematic uniform random sections (30 microm thick), a smooth fractionator sampling scheme was applied to the liver of five male Wistar rats (3 month old). Those sections were immunostained with polyclonal antibodies against carcinoembryonic antigen. Because biliary canaliculi were then marked, an unequivocal counting of mononucleated hepatocytes (MnHEP) and BnHEP was allowed. RESULTS: The N of HEP was estimated to be 1.93 x 10(9), with a coefficient of error (CE) of 0.02, corresponding to 129 x 10(6) HEP/g of liver. BnHEP represented 26% of total HEP number. The N of NHC was estimated as 1.31 x 10(9) (CE=0.02). CONCLUSION: The strategy here presented provides a reliable method for accessing the N of HEP (distinguishing MnHEP from BnHEP) in situations in which these parameters are relevant, namely for evaluating the magnitude of an hyperplastic liver response from its very early onset. 相似文献
999.
Magdalena Sanz-Cortés Víctor Martín González Francisco Raga Baixauli Fernando Bonilla-Musoles 《Progresos de Obstetricia y Ginecología》2006
We report the case of a patient with synchronous neoplasms of the endometrium and ovary, which developed at a relatively young age (45 years). Clinical presentation consisted of hypermenorrhea. An ovarian tumor was subsequently detected through ultrasound and computed tomography. Pathological examination revealed endometrioid histology at both sites and, as in most synchronous tumors occurring in these locations, both the grade and the stage of the tumors were low. All these factors indicate a good prognosis. 相似文献
1000.