全文获取类型
收费全文 | 45364篇 |
免费 | 2235篇 |
国内免费 | 370篇 |
专业分类
耳鼻咽喉 | 468篇 |
儿科学 | 830篇 |
妇产科学 | 1315篇 |
基础医学 | 5387篇 |
口腔科学 | 1715篇 |
临床医学 | 3501篇 |
内科学 | 12717篇 |
皮肤病学 | 927篇 |
神经病学 | 3964篇 |
特种医学 | 1202篇 |
外科学 | 6895篇 |
综合类 | 172篇 |
一般理论 | 9篇 |
预防医学 | 2474篇 |
眼科学 | 720篇 |
药学 | 2450篇 |
中国医学 | 115篇 |
肿瘤学 | 3108篇 |
出版年
2024年 | 41篇 |
2023年 | 321篇 |
2022年 | 781篇 |
2021年 | 1477篇 |
2020年 | 792篇 |
2019年 | 1127篇 |
2018年 | 1555篇 |
2017年 | 1022篇 |
2016年 | 1116篇 |
2015年 | 1313篇 |
2014年 | 1797篇 |
2013年 | 2372篇 |
2012年 | 3640篇 |
2011年 | 3590篇 |
2010年 | 2020篇 |
2009年 | 1759篇 |
2008年 | 3066篇 |
2007年 | 3167篇 |
2006年 | 2967篇 |
2005年 | 2932篇 |
2004年 | 2640篇 |
2003年 | 2374篇 |
2002年 | 2096篇 |
2001年 | 306篇 |
2000年 | 209篇 |
1999年 | 313篇 |
1998年 | 373篇 |
1997年 | 330篇 |
1996年 | 288篇 |
1995年 | 282篇 |
1994年 | 224篇 |
1993年 | 169篇 |
1992年 | 147篇 |
1991年 | 106篇 |
1990年 | 109篇 |
1989年 | 88篇 |
1988年 | 73篇 |
1987年 | 60篇 |
1986年 | 76篇 |
1985年 | 73篇 |
1984年 | 77篇 |
1983年 | 68篇 |
1982年 | 94篇 |
1981年 | 68篇 |
1980年 | 72篇 |
1979年 | 41篇 |
1978年 | 49篇 |
1977年 | 38篇 |
1976年 | 36篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
David Jiménez Castro Gema Díaz David Martí Carlos Escobar Javier Ortega Sergio García-Rull Joaquin Picher Antonio Sueiro 《Blood coagulation & fibrinolysis》2007,18(2):173-177
This study aimed to determine whether a weight-adjusted dose of subcutaneous enoxaparin is as effective and safe as oral acenocoumarol for the secondary prophylaxis of pulmonary embolism. Three hundred and eighty consecutive noncancer outpatients hospitalized with an episode of symptomatic pulmonary embolism selected treatment with acenocoumarol or enoxaparin at a dose of 1 mg/kg once daily after being informed of the type of administration and expected frequency of laboratory monitoring for both medicinal products. Endpoints were symptomatic recurrent thromboembolic events evaluated by standard objective testing, and a composite endpoint of recurrent venous thromboembolism, major bleeding, and death from any cause. One hundred and ninety-nine patients (52%) chose acenocoumarol therapy and 181 chose enoxaparin monotherapy. Four patients in the enoxaparin group (2.2%) and six patients in the acenocoumarol group (3%) had an objective thromboembolic recurrence (hazard ratio, 1.35; 95% confidence interval, 0.38-4.79; P = 0.64). Nine patients in the enoxaparin group (5.0%) had a hemorrhagic complication compared with 11 in the acenocoumarol group (5.5%) (P = 0.81). The hospital length of stay was shorter with enoxaparin compared with acenocoumarol (11 versus 16 days, P = 0.0001). Enoxaparin is as effective and safe as acenocoumarol in the secondary prevention of recurrent thromboembolic disease and is associated with shorter hospitalization. 相似文献
43.
Monica Conciatori Christopher J Stodgell Susan L Hyman Melanie O'Bara Roberto Militerni Carmela Bravaccio Simona Trillo Francesco Montecchi Cindy Schneider Raun Melmed Maurizio Elia Lori Crawford Sarah J Spence Lucianna Muscarella Vito Guarnieri Leonardo D'Agruma Alessandro Quattrone Leopoldo Zelante Daniel Rabinowitz Tiziana Pascucci Stefano Puglisi-Allegra Karl-Ludvig Reichelt Patricia M Rodier Antonio M Persico 《Neuropsychopharmacology》2004,55(4):413-419
BACKGROUND: The HOXA1 gene plays a major role in brainstem and cranial morphogenesis. The G allele of the HOXA1 A218G polymorphism has been previously found associated with autism. METHODS: We performed case-control and family-based association analyses, contrasting 127 autistic patients with 174 ethnically matched controls, and assessing for allelic transmission disequilibrium in 189 complete trios. RESULTS: A, and not G, alleles were associated with autism using both case-control (chi(2) = 8.96 and 5.71, 1 df, p <.005 and <.025 for genotypes and alleles, respectively), and family-based (transmission/disequilibrium test chi(2) = 8.80, 1 df, p <.005) association analyses. The head circumference of 31 patients carrying one or two copies of the G allele displayed significantly larger median values (95.0th vs. 82.5th percentile, p <.05) and dramatically reduced interindividual variability (p <.0001), compared with 166 patients carrying the A/A genotype. CONCLUSIONS: The HOXA1 A218G polymorphism explains approximately 5% of the variance in the head circumference of autistic patients and represents to our knowledge the first known gene variant providing sizable contributions to cranial morphology. The disease specificity of this finding is currently being investigated. Nonreplications in genetic linkage/association studies could partly stem from the dyshomogeneous distribution of an endophenotype morphologically defined by cranial circumference. 相似文献
44.
45.
46.
Abstract: The use of neuromuscular electrical stimulation (NMES) for rehabilitation of gait in spinal patients is widely known. The best results can be obtained with the use of biomechanical sensors and a closed loop NMES system. One of the biggest problems faced in the design of control systems for closed-loop operation, in gait rehabilitation, is the variation of the mechanical conditions during the phases of gait. This work presents a new approach to ease the design of rule-based closed loop systems for operation in conditions such as gait rehabilitation. 相似文献
47.
Basilio Pispisa Mariano Venanzi Antonio Palleschi Maria D'Alagni 《Macromolecular chemistry and physics.》1995,196(9):2809-2825
The photophysics of protoporphyrin-naphthyl (P-N) pairs covalently and randomly bound to the ε-amino groups of the side-chains of poly(L -lysine) (PL) were investigated by steady-state and time-resolved fluorescence measurements. The results indicate that quenching of excited naphthalene (λex = 280 nm) chiefly occurs by interconversion to the triplet state when the polymeric matrix is in random coil (pH ≈ 7) and by intramolecular electron transfer from ground-state porphyrin, P → 1N*, when the polypeptide is in α-helical conformation (pH ≈ 11), the specific rate constant of the electron transfer being 3,1 · 107 s?1 (25°C). PNPL exhibits very little exciplex fluorescence, whatever the pH, suggesting both a reduced internal Brownian motion of the chromophores, owing to the amide bond in the substituted side-chains, and a relatively large average interprobe separation distance. This agrees with polarized fluorescence data and with the results of a conformational statistics analysis on the fully ordered PNPL, indicating that the average interchromophoric distance for which the electron transfer has the highest probability to occur is around 12 Å. The computational results allowed us to reproduce the experimental fluorescence decay curves and estimate the parameters governing the electron transfer process. Implications of these findings on the relaxation time of the heli-xcoil transition in PNPL are briefly discussed. 相似文献
48.
Jos Meseguer Antonio Lpez-Ruiz Alfonsa Garcí-Ayala 《Anatomical record (Hoboken, N.J. : 2007)》1995,241(3):303-309
Background: Head-kidney, considered the major fish lympho-haemopoietic tissue, consists of cells of the different haemopoietic series supported by a network of stromal cells whose morphofunctional properties have not been established. We report the ultrastructure and cytochemical features of the reticulo-endothelial stroma of the head-kidney from the seawater teleost gilthead seabream (Sparus aurata L.). Methods: Samples of head-kidney were processed for electron microscopic study. Some of the samples were incubated for acid and alkaline phosphatase, peroxidase, glucose-6-phosphatase, or ATPase. Results: The reticulo-endothelial stroma of gilthead seabream head-kidney consists of sinusoidal cells (endothelial and adventitial cells) and reticular cells (macrophage-type reticulum and fibroblast-like reticular cells). Transcytosis vesicles and rounded medium electron-dense granules were observed in the cytoplasm of the endothelial cells. The adventitial cells partially covered the outside surface of the endothelial cells and were joined by desmosomes. The macrophage-type reticulum cells were characterized by their cytoplasmic processes and acid phosphatase positive lysosomes. The fibroblast-like reticular cells were joined by desmosomes and formed an extensive network between the haemopoietic parenchyma. They were peroxidase negative and acid and alkaline phosphatase, glucose-6-phosphatase, β-glucuronidase, and ATPase positive. Conclusions: The ultrastructural and cytochemical features of the reticulo-endothelial stroma of the gilthead seabream head-kidney are similar to those of mammalian bone marrow, suggesting phylogenetic analogies between both tissues. © 1995 Wiley-Liss, Inc. 相似文献
49.
50.
Successful Liver and Kidney Transplantation From Cadaveric Donors With Left-Sided Bacterial Endocarditis 总被引:1,自引:0,他引:1
Francisco Caballero Antonio Lopez-Navidad Milagrosa Perea Catiana Cabrer Lluis Guirado Ricard Solà 《American journal of transplantation》2005,5(4):781-787
Bacterial infections are frequent in cadaveric organ donors and can be transmitted to the transplantation recipient, which could have devastating consequences for the recipients if adequate preventive measures are not adopted.
From the 355 consecutive brain dead cadaveric organ donors procured at our center in the last four years, 2000–2003, four of them (1.1%) had bacterial endocarditis as cause of death. The bacteria responsible for the endocarditis were Staphylococcus epidermidis, coagulase-negative Staphylococcus , Staphylococcus hominis and Streptococcus viridans , respectively. We performed five kidney and two liver transplantations on seven recipients. All donors and recipients received antibiotic treatment against the germ causing the respective endocarditis.
Infection by the bacteria responsible for the endocarditis in the respective donors was not transmitted to any of the recipients. Six of the seven recipients were alive with normal-functioning grafts after between 13 and 24 months' follow-up. Transplantectomy was performed on one kidney recipient due to thrombosis of the renal vein of the graft not related to the endocarditis.
Liver and kidney transplantation from donors dying from bacterial endocarditis can be performed without causing the transmission of infection to the recipient or the dysfunction of the graft. 相似文献
From the 355 consecutive brain dead cadaveric organ donors procured at our center in the last four years, 2000–2003, four of them (1.1%) had bacterial endocarditis as cause of death. The bacteria responsible for the endocarditis were Staphylococcus epidermidis, coagulase-negative Staphylococcus , Staphylococcus hominis and Streptococcus viridans , respectively. We performed five kidney and two liver transplantations on seven recipients. All donors and recipients received antibiotic treatment against the germ causing the respective endocarditis.
Infection by the bacteria responsible for the endocarditis in the respective donors was not transmitted to any of the recipients. Six of the seven recipients were alive with normal-functioning grafts after between 13 and 24 months' follow-up. Transplantectomy was performed on one kidney recipient due to thrombosis of the renal vein of the graft not related to the endocarditis.
Liver and kidney transplantation from donors dying from bacterial endocarditis can be performed without causing the transmission of infection to the recipient or the dysfunction of the graft. 相似文献