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91.
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目的:研究胰岛素样生长因子I(IGF I)和人绒毛膜促性腺激素(hCG)对成年大鼠睾丸Leydig细胞中葡萄糖转运蛋白(GLUT)基因表达的影响,为进一步探讨Leydig细胞中睾酮的合成、分泌与葡萄糖代谢的关系提供依据。方法:采用改良的Klinefelter方法从成年大鼠睾丸中分离获得Leydig细胞;用反转录聚合酶链技术检测IGF I和hCG对原代培养的Leydig细胞中GLUT基因表达的调控作用。结果:分离得到纯度为98%的大鼠Leydig细胞,并与对照组比较,hCG可显著增加Leydig细胞中GLUT8基因mRNA的表达水平(P<0.001),且此作用具有剂量依赖性与时效性。当在试验组细胞中单独加入IGF I或IGF I和hCG作用于细胞后,发现IGF I(100ng mL)可显著增加Leydig细胞中GLUT8基因mRNA的表达(P<0.01),也可与hCG协同作用显著提高GLUT8基因的mRNA表达,该结果与IGF I(100ng mL)和hCG(10ng mL)能协同作用极显著增加睾酮合成水平(P<0.001)的结果是相吻合的。在大鼠Leydig细胞中,无论10ng mL或100ng mL还是两者同时作用于细胞,都不能影响GLUT1和GLUT3基因的mRNA水平。结论:在成年大鼠Leydig细胞中,IGF I和hCG对细胞中的GLUT8基因表达的调节作用具有特异性,其协同作用能显著提高细胞中GLUT8基因mRNA水平,增强细胞摄取葡萄糖的能力,给细胞提供更多的代谢能源,最终增加Leydig细胞睾酮的合成与分泌。 相似文献
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de Roode DF Balk L Koeman JH 《Archives of environmental contamination and toxicology》2000,39(3):386-391
A test system was developed to examine the effects of environmental contaminants on thiamine homeostasis in bird embryos.
This system employs fresh chicken egg yolk lipids as a vehicle for use in egg injection studies. Furazolidone, an antibiotic
suspected to interfere with thiamine metabolism, was used as a positive control to evaluate the utility of the test system.
It was determined that fresh chicken egg yolk lipids were preferable over chemical vehicles as it resulted in lower mortality
rates (16% versus 23–62%) and did not induce any observable effects in the embryo. Injection of 1 mg/egg of furazolidone at
day 0 of development resulted in decreased respiration followed by death, with mortality rates being twice as high as in carrier
controls. In addition, transketolase activity, which was measured as an indicator of thiamine availability in the body, was
decreased 25% in brains of 19-day-old embryos. This mechanism may be of importance for effects of environmental contaminants
in wild bird populations.
Received: 3 November 1999/Accepted: 29 March 2000 相似文献
95.
AS Grumach RC Carmona D Lazarotti MA Ribeiro RB Rozentraub ML Racz A Weinberg MMS Carneiro-Sampaio 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(3):284-290
Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n=16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight ( n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages. 相似文献
96.
A.J. Ouwehand C.C. Baan L.M.B. Vaessen N.H.P.M. Jutte A.H.M.M. Balk E. Bos F.H.J. Claas W. Weimar 《Transplant international》1992,5(Z1):S673-S675
We studied the influence of HLA mismatches on T lymphocyte cultures that were derived from endomyocardial biopsies (EMB) from 118 heart transplant recipients. From patients with DR mismatches, the majority of the EMB-derived cultures were dominated by CD4, while in patients without DR mismatches, CD8 was the predominant T cell subset. The majority (75) of the cultures were cytotoxic against donor antigens. A significantly (P < 0.005) lower proportion of the cultures showed cytotoxicity (36 %) against HLA-A antigens when compared to HLA-B (53 %) or HLA-DR (49 %). A dose effect phenomenon was detected for all HLA antigens, including HLA-A: a higher number of A, B or DR mismatches resulted in a higher number of cytotoxic cultures directed against these antigens. B and DR matching had the greatest influence on 6 month freedom from rejection. Both our experimental and clinical data indicated that HLA matching played a role in the immune response against a transplanted heart. 相似文献
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N. M. van Besouw C. R. Daane P. de Kuiper T. van Gelder B. Mochtar A. H. M. M. Balk L. M. B. Vaessen W. Weimar 《Transplant international》1998,11(S1):S364-S366
Abstract Cellular mechanisms may play a role in the development of graft vascular disease (GVD). We previously demonstrated that GVD correlated with an increase of donor-specific T-helper 1 cytokine production by graft-infiltrating lymphocytes but not by peripheral blood mononuclear cells (PBMC). These T-helper 1 cytokines aid the generation of cytotoxic T-lymphocytes (CTL). In the present report, we investigated whether there is a relationship between the frequency of donor-specific CTL precursors (pCTL) in PBMC and the development of GVD. We tested PBMC samples of five patients with GVD and five patients without GVD in the periods 3–6 months, 1 year, and 3 years after heart transplantation. At all time points, GVD was not related to the number of pCTL. In conclusion, donor-specific cellular tests in peripheral blood could not be related to GVD. Apparently, donor-specific reactions associated with the induction of GVD can only be monitored in the graft. 相似文献
100.