全文获取类型
收费全文 | 26450篇 |
免费 | 1300篇 |
国内免费 | 251篇 |
专业分类
耳鼻咽喉 | 214篇 |
儿科学 | 514篇 |
妇产科学 | 620篇 |
基础医学 | 2778篇 |
口腔科学 | 524篇 |
临床医学 | 2293篇 |
内科学 | 7696篇 |
皮肤病学 | 566篇 |
神经病学 | 2344篇 |
特种医学 | 925篇 |
外科学 | 4327篇 |
综合类 | 63篇 |
一般理论 | 5篇 |
预防医学 | 955篇 |
眼科学 | 346篇 |
药学 | 1380篇 |
中国医学 | 43篇 |
肿瘤学 | 2408篇 |
出版年
2024年 | 27篇 |
2023年 | 224篇 |
2022年 | 461篇 |
2021年 | 776篇 |
2020年 | 490篇 |
2019年 | 642篇 |
2018年 | 763篇 |
2017年 | 588篇 |
2016年 | 725篇 |
2015年 | 784篇 |
2014年 | 1001篇 |
2013年 | 1375篇 |
2012年 | 2123篇 |
2011年 | 2085篇 |
2010年 | 1223篇 |
2009年 | 1095篇 |
2008年 | 1911篇 |
2007年 | 1809篇 |
2006年 | 1657篇 |
2005年 | 1666篇 |
2004年 | 1523篇 |
2003年 | 1351篇 |
2002年 | 1252篇 |
2001年 | 161篇 |
2000年 | 109篇 |
1999年 | 163篇 |
1998年 | 219篇 |
1997年 | 200篇 |
1996年 | 154篇 |
1995年 | 185篇 |
1994年 | 149篇 |
1993年 | 140篇 |
1992年 | 89篇 |
1991年 | 78篇 |
1990年 | 88篇 |
1989年 | 53篇 |
1988年 | 51篇 |
1987年 | 44篇 |
1986年 | 51篇 |
1985年 | 52篇 |
1984年 | 57篇 |
1983年 | 41篇 |
1982年 | 53篇 |
1981年 | 32篇 |
1980年 | 44篇 |
1979年 | 28篇 |
1978年 | 15篇 |
1977年 | 18篇 |
1975年 | 20篇 |
1974年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Bjarnarson SP Jakobsen H Del Giudice G Trannoy E Siegrist CA Jonsdottir I 《European journal of immunology》2005,35(4):1037-1045
The aim of vaccination is to rapidly elicit protective immunity and generate memory for sustained protection. We studied the induction and persistence of polysaccharide (PS)-specific memory in neonatal and infant mice primed with pneumococcal conjugate (Pnc1-TT) by assessing the response to native pneumococcal PS (PPS-1), the kinetics of the PPS-1-specific IgG response to a second Pnc1-TT dose and affinity maturation. A subcutaneous (s.c.) Pnc1-TT booster induced a rapid increase in PPS-1-specific IgG, indicating efficient priming for memory by a single dose of Pnc1-TT already at 1 week of age. High levels were maintained for >12 weeks. However, a PPS-1 booster induced no response in neonatal or infant mice. The adjuvant LT-K63 significantly enhanced the IgG response and affinity to Pnc1-TT by both the s.c. and the intranasal (i.n.) route in all age groups. In neonatal and infant mice, PPS-1 and LT-K63 induced a booster response only when given i.n. following either s.c. or i.n. priming with Pnc1-TT and LT-K63. In contrast, PPS-1 with or without LT-K63 administered s.c. compromised the ongoing PPS-1-specific response elicited in neonatal mice by either s.c. or i.n. priming with Pnc1-TT and LT-K63. These results demonstrate the advantage of the mucosal route for elicitation of PS-specific memory responses in early life. 相似文献
72.
Lucia MB Rutella S Leone G Larocca LM Vella S Cauda R 《Journal of acquired immune deficiency syndromes (1999)》2002,30(4):369-378
P-glycoprotein (P-gp) transports a wide range of structurally unrelated drugs, such as HIV protease inhibitors (PIs) and cytotoxic compounds such as anthracyclines. Because modification of P-gp phenotype and function is an important underlying mechanism of drug interactions, the current study was conducted in order to evaluate whether highly active antiretroviral therapy (HAART), HIV plasma viral load (VL), or cancer chemotherapy may induce in vivo changes of P-gp phenotype in peripheral blood mononuclear cells (PBMCs) from HIV-infected treatment-naive and -experienced subjects at different stages of HIV infection and/or disease, including patients with HIV-associated Kaposi sarcoma (KS). Our results show that neither HAART nor HIV VL, nor the stage of HIV infection and/or disease, significantly alter P-gp expression on PBMCs. In particular, surface P-gp expression is expressed at low levels by T-cell subsets, B cells, and NK cells, whereas almost all monocytes are double positive and these results are not modified by HIV PI-containing regimens. By contrast, a significant phenotype modification is detected in PBMCs from AIDS/KS patients after challenge with the liposomal formulation of the anthracycline doxorubicin (L-DOX) with the higher expression reached 24 hours after the end of the drug infusion. In addition, accumulation of L-DOX is unaffected by P-gp-mediated drug efflux as documented by in vitro experiments, in sharp contrast to the kinetic of free DOX, based on HIV PI blockade experiments. Finally, P-gp expression was found in KS spindle cells from HIV-infected treatment-naive AIDS/KS patients. We conclude that P-gp phenotype in PBMCs and specific subsets is not altered by HAART and/or HIV, whereas a significant increase is induced by specific anticancer drugs such as L-DOX. Moreover, HIV PIs possess an inhibitory effect on P-gp function that may improve DOX sensitivity in KS spindle cells. 相似文献
73.
Aldo Scarpa Franco Bonetti Fabio Menestrina Marta Menegazzi Marco Chilosi Maurizio Lestani Chiara Bovolenta Giuseppe Zamboni L. Fiore-Donati 《Virchows Archiv : an international journal of pathology》1987,412(1):17-21
Summary The Southern blot hybridization technique has been applied to study the configuration of immunoglobulin and T-cell receptor genes in 6 cases of the so called mediastinal large cell lymphoma with sclerosis. This lymphoma has been recently recognized as a separate entity among non-Hodgkin lymphomas mainly affecting young adult patients. The B-cell origin of this neoplasm was suggested by means of immunohistochemical analysis. However, the immunophenotypical B-cell related markers used do not always exhibit lineage fidelity. The Southern blot analysis demonstrated the presence of unique heavy and k-light chain immunoglobulin gene rearrangements, establishing genotypically their B-cell origin.This work was supported by the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy, and Progetto finalizzato Oncologia (contratto no 86.00461.44), CNR, Rome, Italy. Aldo Scarpa and Maurizio Lestani are supported by a Scholarship from the Associazione Italiana per la Ricerca sul Cancro, Milano, Italy 相似文献
74.
Maristella?D'Uva Ida?Strina Antonio?Mollo Antonio?Ranieri Giuseppe?De Placido Pierpaolo?Di MiccoEmail author 《Journal of translational medicine》2005,3(1):43
Background
Antiphospholipid syndrome (APS) has been often associated to RPL since 1980 and some reports in the Literature rarely described antibodies to factor XII in patients with APS. 相似文献75.
Nappi C Di Spiezio Sardo A Guerra G Di Carlo C Bifulco G Acunzo G Sammartino A Galli V 《Menopause (New York, N.Y.)》2004,11(4):447-455
OBJECTIVE: To compare nasal symptomatology and function and local concentrations of estradiol (E2), estradiol receptor (ERalpha), vasoactive intestinal peptide (VIP), substance P (SP) and neuropeptide Y (NPY) in nasal biopsies of 20 postmenopausal women complaining of paradoxical nasal stuffiness before and after treatment with intranasal or transdermal E2. DESIGN: Twenty healthy postmenopausal women willing to start hormone therapy (HT) were allocated to one of two groups, using a computer-generated randomization list.Ten postmenopausal women were treated with transdermal 17beta-estradiol 50 microg daily plus nomegestrole acetate 5 mg/day for 12 days per 28-day cycle for 6 months (Group A). Ten postmenopausal women were treated with intranasal 17beta-estradiol 300 microg/day (one spray delivery of 150 microg per nostril) plus nomegestrole acetate 5 mg/day for 12 days per 28-day cycle for 6 months (Group B). Fourteen fertile women undergoing nasal mucosa biopsy during plastic surgery were used as controls for the immunohistochemical evaluation (Group C).All women in groups A and B underwent evaluation of nasal stuffiness score, mucociliary transport time, rhinoscopy, and active anterior rhinomanometry at the beginning of the study and after, VIP, SP, and 6 months of HT. Nasal biopsies and evaluation of local concentrations of E2, ERalpha NPY were performed in groups A and B before and after 6 months of HT and in group C. RESULTS: Both intranasal and transdermal HT improve nasal symptomatology and nasal mucosa appearance and reduce mean mucociliary transport time. The effectiveness of intranasally administered therapy at improving nasal function is significantly better than transdermal therapy. In comparison with premenopausal controls, untreated postmenopausal women of group A and B showed significantly decreased immunopositivity for E2, ERalpha, and SP. HT induced a significant increase in E2, ERalpha, VIP, and SP and a decrease in NPY immunopositivity. Intranasal therapy was associated with a significantly higher immunopositivity for VIP and SP. CONCLUSIONS: HT improves nasal function and symptomatology in postmenopausal women with paradoxical nasal stuffiness, modulating nasal mucosa function through an action on cholinergic, adrenergic, and sensory peptides. Intranasally administered HT is more effective at improving nasal function than transdermal HT. 相似文献
76.
Giovanni Camussi Ciro Tetta Giuseppe Segoloni M. Chiara Deregibus Federico Bussolino 《Inflammation research》1981,11(6-7):550-553
Soluble and phagocytic stimuli released PAF-acether from PMN leucocytes, as determined by chromatography and bioassay by platelet aggregation. The same material caused aggregation of human and rabbit PMN leucocytesin vitro which was inhibited by ETYA and PGI2. PGI2 also inhibited PAF-acether release by PMN leucocytes and,in vivo, PGI2 abolished not only PAF-acether-induced, but also immune complex or C5a-induced thrombocytopenia and neutropenia in rabbits. These data suggest that PAF-acether may be involved in activation of both platelets and PMN leucocytesin vivo. 相似文献
77.
Salvatore Battaglia Giuseppe Barbolini Annibale R. Botticelli 《Virchows Archiv : an international journal of pathology》1979,382(3):245-259
Summary This study was performed in order to elucidate some of the problems of incidence, morphology and natural history concerned with Stage A prostatic cancer or prostatic microcarcinoma (PMC).The prostates of 100 patients, treated by subtotal prostatectomy for benign prostatic hyperplasia (BPH), were studied by comparing both routine and step-section techniques. The incidence of PMC was 41% by the former and 86% by the latter technique. Assessment of the size of PMC, as measured by the sum of the two main diameters, resulted in three groups: A1, A2, A3. The last of these may represent a frankly malignant condition, judged by size and the histological appearance. Radical prostatectomy is strongly suggested as appropriate therapy for this group.Supported in part by a Grant from the Ministry of Education (art. 286 T.U., 1977/78) 相似文献
78.
Effects of HDL3 on the expression of matrix-degrading proteases in human endothelial cells 总被引:1,自引:0,他引:1
Norata GD Pellegatta F Hamsten A Catapano AL Eriksson P 《International journal of molecular medicine》2003,12(1):73-78
Modified lipoproteins have been suggested to modulate the expression of matrix-degrading proteases in the vascular wall. Since oxidized high density lipoprotein (HDL) has been found in atheromatous plaques and receptors for modified HDL are present on endothelial cells, we investigated the role of native and oxidized HDL3 on the expression of 35 proteases and their inhibitors in human endothelial cells using microarray analysis. Matrix metalloproteinase (MMP)-1, -2, -10, -13 and -14, tissue inhibitor of MMP (TIMP)-1, -2 and -3, cathepsin B and D, and cystatin C were expressed under basal conditions, of which MMP-10 and cystatin C expression have not been described before in endothelial cells. Native HDL3 increased MMP-1 and MMP-14 expression and decreased MMP-13 expression, whereas oxidized HDL3 increased PAI-1 and MMP-1 expression. The expression pattern was confirmed by quantitative real-time PCR. In summary, a large repertoire of matrix-degrading proteases is expressed in endothelial cells, an expression that can be modulated by native and oxidized HDL3. 相似文献
79.
Radi O Parma P Imbeaud S Nasca MR Uccellatore F Maraschio P Tiepolo L Micali G Camerino G 《American journal of medical genetics. Part A》2005,(3):241-246
We describe a large inbred Sicilian family that includes four 46, XX (SRY-) brothers. Palmoplantar hyperkeratosis (PPK) and an associated predisposition to squamous cell carcinoma (SCC) of the skin, segregates as a recessive trait within the family. Interestingly, all the PPK-affected members of the family are phenotypic males (46,XY or 46,XX) while seven XX sibs are healthy phenotypic females with no signs of PPK. We propose that homozygosity for a single mutational event, possibly including contiguous genes, may cause PPK/SCC in both XY or XX individuals and sex reversal in XX individuals. The family is informative for linkage analysis for the PPK trait and allows linkage exclusion for the sex reversal trait. Here we show that 15 loci involved in PPK etiology, skin differentiation, function or malignancy, and nine loci involved in sex determination/differentiation are not implicated in the phenotype of this family. 相似文献
80.
Niggli HJ Tudisco S Privitera G Applegate LA Scordino A Musumeci F 《Journal of biomedical optics》2005,10(2):024006
Photobiological research in the last 30 yr has shown the existence of ultraweak photon emission in biological tissue, which can be detected with sophisticated photomultiplier systems. Although the emission of this ultraweak radiation, often termed biophotons, is extremely low in mammalian cells, it can be efficiently increased by ultraviolet light. Most recently it was shown that UV-A (330 to 380 nm) releases such very weak cell radiation in differentiated human skin fibroblasts. Based on these findings, a new and powerful tool in the form of UV-A-laser-induced biophotonic emission of cultured cells was developed with the intention to detect biophysical changes between carcinogenic and normal cells. With suspension densities ranging from 1 to 8 x 10(6) cells/mL, it was evident that an increase of the UV-A-laser-light induced photon emission intensity could be observed in normal as well as melanoma cells. Using this new detection procedure of ultraweak light emission, photons in cell suspensions as low as 100 microL could be determined, which is a factor of 100 lower compared to previous procedures. Moreover, the detection procedure has been further refined by turning off the photomultiplier system electronically during irradiation leading to the first measurements of induced light emission in the cells after less than 10 micros instead of 150 ms, as reported in previous procedures. This improvement leads to measurements of light bursts up 10(7) photons/s instead of several hundred as found with classical designs. Overall, we find decreasing induction ratings between normal and melanoma cells as well as cancer-prone and melanoma cells. Therefore, it turns out that this highly sensitive and noninvasive device enables us to detect high levels of ultraweak photon emission following UV-A-laser-induced light stimulation within the cells, which enables future development of new biophysical strategies in cell research. 相似文献