全文获取类型
收费全文 | 30286篇 |
免费 | 1688篇 |
国内免费 | 116篇 |
专业分类
耳鼻咽喉 | 399篇 |
儿科学 | 695篇 |
妇产科学 | 797篇 |
基础医学 | 3790篇 |
口腔科学 | 1702篇 |
临床医学 | 2300篇 |
内科学 | 7756篇 |
皮肤病学 | 727篇 |
神经病学 | 2477篇 |
特种医学 | 741篇 |
外科学 | 4005篇 |
综合类 | 152篇 |
一般理论 | 6篇 |
预防医学 | 2722篇 |
眼科学 | 454篇 |
药学 | 1835篇 |
中国医学 | 196篇 |
肿瘤学 | 1336篇 |
出版年
2023年 | 287篇 |
2022年 | 673篇 |
2021年 | 1168篇 |
2020年 | 671篇 |
2019年 | 970篇 |
2018年 | 1259篇 |
2017年 | 771篇 |
2016年 | 802篇 |
2015年 | 932篇 |
2014年 | 1358篇 |
2013年 | 1571篇 |
2012年 | 2336篇 |
2011年 | 2526篇 |
2010年 | 1336篇 |
2009年 | 1119篇 |
2008年 | 1888篇 |
2007年 | 1803篇 |
2006年 | 1595篇 |
2005年 | 1583篇 |
2004年 | 1379篇 |
2003年 | 1149篇 |
2002年 | 1073篇 |
2001年 | 410篇 |
2000年 | 424篇 |
1999年 | 383篇 |
1998年 | 197篇 |
1997年 | 142篇 |
1996年 | 138篇 |
1995年 | 117篇 |
1994年 | 102篇 |
1993年 | 87篇 |
1992年 | 173篇 |
1991年 | 152篇 |
1990年 | 144篇 |
1989年 | 131篇 |
1988年 | 107篇 |
1987年 | 104篇 |
1986年 | 101篇 |
1985年 | 99篇 |
1984年 | 83篇 |
1983年 | 70篇 |
1982年 | 50篇 |
1981年 | 37篇 |
1980年 | 44篇 |
1979年 | 46篇 |
1978年 | 40篇 |
1975年 | 37篇 |
1974年 | 41篇 |
1973年 | 54篇 |
1971年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
51.
Andre d'Avila M.D. Pedro Brngada M.D. 《Pacing and clinical electrophysiology : PACE》1994,17(11):1832-1833
52.
53.
Effective high-capacity gutless adenoviral vectors mediate transgene expression in human glioma cells. 总被引:2,自引:0,他引:2
Marianela Candolfi James F Curtin Wei-Dong Xiong Kurt M Kroeger Chunyan Liu Altan Rentsendorj Hasmik Agadjanian Lali Medina-Kauwe Donna Palmer Philip Ng Pedro R Lowenstein Maria G Castro 《Molecular therapy》2006,14(3):371-381
Glioblastoma multiforme (GBM) is the most common subtype of primary malignant brain tumor. Although serotype 5 adenoviral vectors (Ads) have been used successfully in clinical trials for GBM, the capacity of Ads to infect human glioma cells and the expression of adenoviral receptors in GBM cells have been challenged. In this report, we studied the expression of three molecules that have been shown to mediate adenoviral entry into cells, i.e., coxsackie and adenovirus receptor (CAR), integrin alphavbeta3 (INT), and major histocompatibility complex class I (MHCI), in rodent glioma cell lines and low-passage primary cultures and cell lines from human GBM. We correlated levels of expression of CAR, INT, and MHCI with transduction efficiency elicited by several high-capacity helper-dependent adenoviral vectors (HC-Ads). Expression levels of adenoviral receptors were variable among the different GBM cells studied. HC-Ad-mediated therapeutic gene expression was efficient, ranging between 20 and 80% of the total target cells expressing the encoded transgenes. Our results show no correlation between the levels of CAR, INT, or MHCI molecules and the levels of transgene expression or the number of GBM cells transduced. We conclude that expression levels of adenoviral receptors do not predict their transduction efficiency or biological function. 相似文献
54.
55.
Javier R Caso María A Moro Pedro Lorenzo Ignacio Lizasoain Juan C Leza 《European neuropsychopharmacology》2007,17(9):600-607
Stress is known to be one of the risk factors of stroke. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. However, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. We have used an acute stress protocol consisting of the exposure of male Fischer rats to an acute, single exposure immobilisation protocol (6 h) prior to permanent middle cerebral artery occlusion (MCAO), and we have found that stress worsens behavioural and neurological outcomes and increased infarct size after MCAO. The possible regulatory role of the TNFalpha and IL-1beta was studied by looking at the release of these cytokines in brain. The results of the present study showed an increase in IL-1beta release in cerebral cortex after exposure to acute stress. Brain levels of IL-1beta are also higher in previously stressed MCAO rats than in MCAO animals without stress. Pharmacological blockade of IL-1beta with an antibody anti-IL-1beta led to a decrease in the infarct size as well as in neurological and behavioural deficits after MCAO. In summary, our results indicate that IL-1beta, but not TNFalpha, accounts at least partly for the worsening of MCAO consequences in brain of rats exposed to acute stress. 相似文献
56.
57.
The trajectory, mass fluxes, and deposition of aerosolized particles in a complex tubular system have been predicted. A procedure based on Lagrangian stochastic modeling is proposed to enable the anticipation of such phenomena, taking advantage of experimental results to characterize the air flow. The predictions have been obtained for pharmaceutical aerosols delivered by dry powder inhalers. A critical assessment of the dispersion model has been carried out using data available in the literature. The procedure assumes a low volume fraction of particles in the simulation of turbulent dispersion, but deposition is physically based on the interaction between the particles and both solid and liquid surfaces. The results were confirmed by experimental tests of powder deposition, run according to the European Pharmacopoeia. A parametric study was also carried out with the aim of providing a more complete evaluation of the model’s performance. The comparison between predictions and experimental results has shown that the model properly describes the deposition of aerosolized particles. 相似文献
58.
E. J. Ramos H. S. Pollinger M. D. Stegall J. M. Gloor A. Dogan J. P. Grande 《American journal of transplantation》2007,7(2):402-407
Rituximab, intravenous immunoglobulin (IVIG) and rabbit antithymocyte globulin (rATG) all have been suggested to have an effect on antibody producing cells, however, supporting data are lacking. To assess the impact of these agents on splenic B‐cell populations in vivo, we retrospectively examined 25 spleens removed from patients treated with these agents as part of desensitization protocols in either ABO incompatible or positive crossmatch living donor kidney transplantation. These were compared to control (CTL) spleens removed for trauma. CTLs and spleens removed at transplant after multiple pretransplant plasmaphereses (PP) plus low‐dose IVIG showed similar large numbers of naïve B cells (CD20+ and CD79+), plasma cells (CD138+) and memory B cells (CD27+ cells). Adding rituximab to this PP/IVIG regimen reduced the number naïve B cells, but had no effect on memory or plasma cells. Combination treatment (PP/IVIG, rituximab and rATG) showed a trend toward the reduction of CD27+ cells, but again plasma cells were unchanged. We conclude that none of these protocols reduces splenic plasma cells in vivo. PP/low‐dose IVIG does not alter splenic B cells, but the addition of rituximab decreases mature B cells. Memory B cells may be affected by combination therapy including rATG and requires further study. 相似文献
59.
Dalton A Anjos Elba C S C Etchebehere Celso D Ramos Allan O Santos César Albertotti Edwaldo E Camargo 《Journal of nuclear medicine》2007,48(5):764-770
PET with (18)F-FDG has been considered of limited value for detection of bladder cancer because of the urinary excretion of the tracer. The purpose of this study was to investigate the role of PET/CT in the detection and restaging of bladder cancer using furosemide and oral hydration to remove the excreted (18)F-FDG from the bladder. METHODS: Seventeen patients with bladder cancer (11 without cystectomy, 6 with total cystectomy and urinary diversion) underwent (18)F-FDG PET/CT from head to the upper thighs 60 min after the intravenous injection of 370 MBq of (18)F-FDG. Additional pelvic images were acquired 1 h after the intravenous injection of furosemide and oral hydration. PET/CT findings were confirmed by MRI, cystoscopy, or biopsy. RESULTS: PET/CT was able to detect bladder lesions in 6 of 11 patients who had not undergone cystectomy. These images changed the PET/CT final reading in 7 patients: Recurrent bladder lesions were detected in 6 patients, pelvic lymph node metastases in 2 patients, and prostate metastasis in 1. This technique overcame the difficulties posed by the urinary excretion of (18)F-FDG. Hypermetabolic lesions could be easily detected by PET and precisely localized in the bladder wall, pelvic lymph nodes, or prostate by CT. Seven of 17 patients (41%) were upstaged only after delayed pelvic images. CONCLUSION: Detection of locally recurrent or residual bladder tumors can be dramatically improved using (18)F-FDG PET/CT with delayed images after a diuretic and oral hydration. 相似文献
60.
Marcos Barbosa-Ferreira Maria Lúcia Zaidan Dagli Paulo César Maiorka Silvana Lima Górniak 《Food and chemical toxicology》2005,43(4):497-503
Senna occidentalis (So) is a weed that grows in pastures along fences and in fields cultivated with cereals such as corn and soybean, and many reports have been showing intoxication with this plant in different animal species. It is also used in many medicinal purposes. The objective of the present study was to better evaluate the toxic effects of prolonged administration of So seeds to rats. Forty male Wistar rats were divided into four groups of 10 animals each, three of them respectively fed rations containing 1%, 2% and 4% So seeds, and the last one (control) fed commercial ration for a period of 2 weeks. Fourteen rats were also used in a pair-feeding (PF) experiment. The rats of the experimental groups showed lethargy, weakness, recumbency, depression and emaciation. Two rats of the 4% group and two of the PF group died during the experiment. Histopathological study showed fiber degenerations in the skeletal (Tibial, pectoral and diaphragm) and cardiac muscles. In the liver parenchyma, was observed vacuolar degeneration and, in the kidney, mild nefrosis in the proximal convoluted tubules. All of these alterations occurred in a dose-dependent fashion. Moderate to severe degeneration and spongiosis in the central nervous system, especially in cerebellum. Electron microscopy revealed mitochondrial lesions in all analyzed tissues. 相似文献