全文获取类型
收费全文 | 1935篇 |
免费 | 139篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 17篇 |
妇产科学 | 11篇 |
基础医学 | 349篇 |
口腔科学 | 19篇 |
临床医学 | 225篇 |
内科学 | 481篇 |
皮肤病学 | 37篇 |
神经病学 | 135篇 |
特种医学 | 124篇 |
外科学 | 205篇 |
综合类 | 4篇 |
预防医学 | 99篇 |
眼科学 | 59篇 |
药学 | 149篇 |
中国医学 | 7篇 |
肿瘤学 | 142篇 |
出版年
2023年 | 9篇 |
2022年 | 68篇 |
2021年 | 125篇 |
2020年 | 54篇 |
2019年 | 56篇 |
2018年 | 58篇 |
2017年 | 31篇 |
2016年 | 44篇 |
2015年 | 71篇 |
2014年 | 68篇 |
2013年 | 78篇 |
2012年 | 126篇 |
2011年 | 121篇 |
2010年 | 68篇 |
2009年 | 58篇 |
2008年 | 94篇 |
2007年 | 92篇 |
2006年 | 85篇 |
2005年 | 88篇 |
2004年 | 79篇 |
2003年 | 60篇 |
2002年 | 70篇 |
2001年 | 17篇 |
2000年 | 26篇 |
1999年 | 25篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 44篇 |
1989年 | 27篇 |
1988年 | 27篇 |
1987年 | 17篇 |
1986年 | 21篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1979年 | 15篇 |
1978年 | 6篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 16篇 |
1973年 | 12篇 |
1972年 | 9篇 |
1971年 | 15篇 |
1970年 | 8篇 |
1969年 | 6篇 |
1968年 | 9篇 |
1967年 | 7篇 |
1966年 | 6篇 |
排序方式: 共有2081条查询结果,搜索用时 93 毫秒
11.
Aksana I. Hubich Alexey Y. Bondar Tatsiana U. Kastsiuk Uladimir A. Kastsiuk Fyodar A. Lakhvich Mikhail V. Sholukh 《Hepatology research》2007,37(6):416-424
Aim: The cytoprotective effects of six novel synthetic prostaglandin A(2) analogs against carbon tetrachloride (CCl(4)) as a toxic agent were studied with isolated rat liver hepatocytes in vitro. Results: It was found that hepatocytes treatment with CCl(4) induced: (i) a significant increase of lactic dehydrogenase (LDH) release from cytoplasm; (ii) leakage of glutamate dehydrogenase (GDH) and acid phosphatase from mitochondria and lysosomes, respectively; (iii) 10-fold increase of trien conjugates formation; and (iv) a reduction of free SH-groups by 50%. Prostanoids U-26, U-9 and U-34 decreased cytotoxic index of CCl(4) on average by 1.5-2.0 times and were more effective than PGI(2), the well-known hepatoprotector of prostanoids type. The protective action of the prostanoids was not a cAMP- or Ca(2+)-dependent process. However, prostanoids U-26, U-9 and U-34 normalized intracellular content of SH-groups, reduced trien conjugates formation by 60-80% and strongly prevented enzyme leakage through cellular membranes. They were also able to inhibit CCl(4) effects via decreasing cytochrome P(450)2E1 activity. Conclusion: The results obtained demonstrate that prostanoids provide cytoprotective effects on liver hepatocytes through the prevention of lipid peroxidation of the plasma and the cellular membranes and maintenance of their barrier function. 相似文献
12.
13.
Anatomical examinations (33 cadavers) for studying parasympathetic innervation of the upper abdominal organs formed the basis for developing a new variant of proximal gastric vagotomy--anterior seromyotomy of the body and fundus of the stomach in combination with posterior truncal or posterior selective vagotomy. This variant excludes mobilization of the esophagus and makes it possible to preserve the ligament apparatus of the esophago-gastric junction as well as the parasympathetic innervation of the pancreas, small and large intestine, kidneys, and adrenals, which may be a measure for the prevention of some ++post-vagotomy complications. 相似文献
14.
D F Egorov I V Poliakov N G Petrova 《Grudnaia i serdechno-sosudistaia khirurgiia / Ministerstvo zdravookhraneniia SSSR [i] Vsesoiuznoe nauchnoe obshchestvo khirurgov》1990,(9):13-15
The article generalizes 17-year experience in the organization of surgical service for patients with disturbed rhythm and conductivity of the heart in Leningrad and the northwest region of the USSR. The work of the city center of surgery of arrhythmias is analysed. Prospective calculations were made. Basically new approaches to determining the regular number of persons on the staff and the number and type or operative interventions are suggested. 相似文献
15.
Alexey V. Mazurov Dimitry V. Vinogradov Svetlana G. Khaspekova Anatoly V. Krushinsky Ludmila V. Gerdeva Sergei A. Vasiliev 《European journal of haematology》1996,57(1):38-41
Abstract: Patient B.G. is a 29-yr-old female with a lifelong bleeding disorder characterized clinically by a highly increased bleeding time, menorrhagias, long-lasting bleeding after cuts and tooth extractions and large post-traumatic haematomas. Her coagulation tests were within normal range, platelet count was 140,000–160,000 per μl, but platelet function was impaired as demonstrated by the absence of collagen-induced aggregation, although no abnormalities were detected in aggregation response to ADP and ristocetin. Morphologically her platelets were characterized by gigantic size – average profile area was about 2.5 times higher than that of control donors, and severe deficiency of α-granules – only 16% of their number in control donors. These features taken together indicated the diagnosis of grey platelet syndrome. As has been shown by quantitative immunoblotting, patient's platelets contained small amounts of α-granule membrane protein P-selectin – about 15% of that in control donors. The content of plasma membrane glycoproteins IIb–IIIa and Ib was not reduced, suggesting the specific deficiency of α-granule membrane protein. Thus, B.G. is the second patient described in the literature (see also Lages et al, J Clin Invest 1991: 87: 919–929) with combined deficiency of α-granules and P-selectin. 相似文献
16.
Herzog BA Ott PA Dittrich MT Quast S Karulin AY Kalbacher H Karges W Tary-Lehmann M Lehmann PV Boehm BO Durinovic-Belló I 《Journal of autoimmunity》2004,23(1):45-54
Active T cell recognition of islet antigens has been postulated as the pathogenic mechanism in human type 1 diabetes, but evidence is scarce. If T cells are engaged, they are expected to display increased clonal size and exhibit a T helper (Th)1/Th2 differentiation state. We used a peptide library that covers tyrosine phosphatase IA-2, a target antigen expressed in pancreatic beta cells, to probe 8 diabetic patients and 5 HLA-matched controls. When tested in a high resolution IFNgamma/IL-4 double color ELISPOT assay directly ex vivo, the number of IA-2-reactive IFNgamma producing cells was 17-fold higher in patients than in controls and IL-4 producing cells were not present. An average of 9 peptides was recognized in the patients vs. one in the controls. Determinant recognition primarily involved CD4+ cells and showed high variability among the patients. Furthermore, anti-CD28 antibody signal enhances quantitative assessment of effector T cells in T1D patients. In vitro expansion with peptides and IL-2 results in detection of responding cells in the controls and loss of disease specificity of the T cell response. Together these data provide strong evidence for the active targeting of IA-2 by Th1 memory effector cells in human type 1 diabetes. 相似文献
17.
Seyrantepe V Poupetova H Froissart R Zabot MT Maire I Pshezhetsky AV 《Human mutation》2003,22(5):343-352
Lysosomal sialidase (EC 3.2.1.18) has a dual physiological function; it participates in intralysosomal catabolism of sialylated glycoconjugates and is involved in cellular immune response. Mutations in the sialidase gene NEU1, located on chromosome 6p21.3, result in autosomal recessive disorder, sialidosis, which is characterized by the progressive lysosomal storage of sialylated glycopeptides and oligosaccharides. Sialidosis type I is a milder, late-onset, normosomatic form of the disorder. Type I patients develop visual defects, myoclonus syndrome, cherry-red macular spots, ataxia, hyperreflexia, and seizures. The severe early-onset form, sialidosis type II, is also associated with dysostosis multiplex, Hurler-like phenotype, mental retardation, and hepatosplenomegaly. We summarize information on the 34 unique mutations determined so far in the sialidase gene, including four novel missense and one novel nonsense mutations found in two Czech and two French sialidosis patients. The analysis of sialidase mutations in sialidosis revealed considerable molecular heterogeneity, reflecting the diversity of clinical phenotypes that make molecular diagnosis difficult. The majority of sialidosis patients have had missense mutations, many of which have been expressed; their effects on activity, stability, intracellular localization, and supramolecular organization of sialidase were studied. A structural model of sialidase allowed us to localize mutations in the sialidase molecule and to predict their impact on the tertiary structure and biochemical properties of the enzyme. 相似文献
18.
Myakov A Nieman L Wicky L Utzinger U Richards-Kortum R Sokolov K 《Journal of biomedical optics》2002,7(3):388-397
We present the design and construction of a fiber optic probe for elastic light scattering spectroscopy in vivo with polarized excitation and polarization sensitive detection. The performance of the fiber probe is evaluated using a suspension of polystyrene spheres placed atop a diffusely scattering substrate, and it demonstrates that the size-dependent characteristics of the scatterers can be extracted in the presence of a highly diffusely scattering background using a linear combination of forward and backward Mie scattering components of the scatterers. Subsequently, Mie theory calculations are performed over a broad range of diagnostically relevant parameters of nuclei-mean diameter, size distribution, and relative refractive index-to understand how the polarized reflectance measurements with the fiber probe can be used to extract morphological information about epithelial tissue. Finally, the feasibility of in vivo measurements with the fiber optic based polarization sensitive light scattering spectroscopy is demonstrated. 相似文献
19.
We propose a method for estimating the evolutionary distance between DNA sequences in terms of insertions and deletions (indels), defined as the per site number of indels accumulated in the course of divergence of the two sequences. We derive a maximal likelihood estimate of this distance from differences between lengths of orthologous introns or other segments of sequences delimited by conservative markers. When indels accumulate, lengths of orthologous introns diverge only slightly slower than linearly, because long indels occur with substantial frequencies. Thus, saturation is not a major obstacle for estimating indel-based evolutionary distance. For introns of medium lengths, our method recovers the known evolutionary distance between rat and mouse, 0.014 indels per site, with good precision. We estimate that mouse-human divergence exceeds rat-mouse divergence by a factor of 4, so that mouse-human evolutionary distance in terms of selectively neutral indels is 0.056. Because in mammals, indels are approximately 14 times less frequent than nucleotide substitutions, mouse-human evolutionary distance in terms of selectively neutral substitutions is approximately 0.8. 相似文献
20.
The term microtubule dynamics is often used to describe assembly/disassembly characteristics of this important cytoskeletal polymer. The ability to image microtubules in live Dictyostelium cells has revealed additional dynamic components, acting on the individual assembled tubules. At least two separate forces are involved, in generation of pronounced bending motions during interphase and in creating tension with the cell cortex. This review attempts to summarize what is known about conventional microtubule dynamics in Dictyostelium as well as to describe these two additional motility components. We propose that these forces are important both in maintaining the overall structure of the microtubule array and in supporting intracellular traffic. 相似文献