全文获取类型
收费全文 | 1892篇 |
免费 | 142篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 137篇 |
妇产科学 | 22篇 |
基础医学 | 371篇 |
口腔科学 | 71篇 |
临床医学 | 205篇 |
内科学 | 421篇 |
皮肤病学 | 8篇 |
神经病学 | 160篇 |
特种医学 | 68篇 |
外科学 | 215篇 |
综合类 | 17篇 |
预防医学 | 171篇 |
眼科学 | 18篇 |
药学 | 61篇 |
肿瘤学 | 85篇 |
出版年
2023年 | 8篇 |
2022年 | 33篇 |
2021年 | 35篇 |
2020年 | 29篇 |
2019年 | 36篇 |
2018年 | 31篇 |
2017年 | 46篇 |
2016年 | 39篇 |
2015年 | 54篇 |
2014年 | 62篇 |
2013年 | 78篇 |
2012年 | 134篇 |
2011年 | 131篇 |
2010年 | 61篇 |
2009年 | 76篇 |
2008年 | 134篇 |
2007年 | 119篇 |
2006年 | 138篇 |
2005年 | 87篇 |
2004年 | 109篇 |
2003年 | 131篇 |
2002年 | 115篇 |
2001年 | 37篇 |
2000年 | 14篇 |
1999年 | 30篇 |
1998年 | 29篇 |
1997年 | 15篇 |
1996年 | 9篇 |
1995年 | 19篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1972年 | 8篇 |
1967年 | 3篇 |
排序方式: 共有2041条查询结果,搜索用时 15 毫秒
1.
Epilepsy After Stroke 总被引:48,自引:4,他引:44
A retrospective follow-up of 200 consecutive stroke patients [ischemic brain infarction (IBI) 157, intracerebral hemorrhage (ICH) 20, subarachnoid hemorrhage (SAH) 23] who were in need of ambulatory rehabilitation was conducted for a mean period of 40 months after stroke. Epilepsy developed in 33 (17%) patients. The occurrence of epilepsy was 14% in IBI, 15% in ICH, and 35% in SAH. Significantly more patients developed epilepsy in the SAH group than in the IBI group (8 of 23 vs. 22 of 157, p less than 0.05). Of the 33 patients, 15% had their first seizures within the first 2 weeks after stroke, and 55% developed epilepsy in 6 months. Forty-eight percent of the patients had generalized seizures. Antiepileptic drug (AED) treatment was started in 28 of 33 patients, of whom 17 still had seizures during follow-up. Epilepsy was an important consequence of stroke among patients who needed rehabilitation, especially in SAH patients. In most, this was due to arterial spasm leading to IBI. 相似文献
2.
Posterolateral diaphragmatic hernia in adults--acute symptoms, diagnosis and treatment. Case report.
V Perhoniemi J Helminen R Luosto 《Scandinavian journal of thoracic and cardiovascular surgery》1992,26(3):225-227
Acute herniation through a posterolateral diaphragmatic defect is rare in adults. Two cases in which such herniation occurred by sudden inversion, a 29-year-old man and a 17-year-old girl, are presented. The symptoms, diagnosis and treatment are discussed. 相似文献
3.
Expression of a partially deleted gene of human type II procollagen (COL2A1) in transgenic mice produces a chondrodysplasia. 总被引:13,自引:3,他引:10
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P Vandenberg J S Khillan D J Prockop H Helminen S Kontusaari L Ala-Kokko 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(17):7640-7644
A minigene version of the human gene for type II procollagen (COL2A1) was prepared that lacked a large central region containing 12 of the 52 exons and therefore 291 of the 1523 codons of the gene. The construct was modeled after sporadic in-frame deletions of collagen genes that cause synthesis of shortened pro alpha chains that associate with normal pro alpha chains and thereby cause degradation of the shortened and normal pro alpha chains through a process called procollagen suicide. The gene construct was used to prepare five lines of transgenic mice expressing the minigene. A large proportion of the mice expressing the minigene developed a phenotype of a chondrodysplasia with dwarfism, short and thick limbs, a short snout, a cranial bulge, a cleft palate, and delayed mineralization of bone. A number of mice died shortly after birth. Microscopic examination of cartilage revealed decreased density and organization of collagen fibrils. In cultured chondrocytes from the transgenic mice, the minigene was expressed as shortened pro alpha 1(II) chains that were disulfide-linked to normal mouse pro alpha 1(II) chains. Therefore, the phenotype is probably explained by depletion of the endogenous mouse type II procollagen through the phenomenon of procollagen suicide. 相似文献
4.
The effects of physical exercise (running) and immobilization (splinting) on chondrocyte ultrastructure were studied in the knee joint articular cartilage of 24 young rabbits. Synthetic activity of the chondrocytes was quantified by measuring the amount of rough endoplasmic reticulum (RER) from electron micrographs using a sterologic point-counting method. Extra loading of the joint by running, or by increased weight-bearing after splinting of the contralateral limb, caused a 20% and 30% increment of RER in the middle and deep zones of the cartilage, respectively, while immobilization decreased the amount of RER by 30% in the superficial zone. Some attempts to repair and regenerate were observed, especially in the deep zone of articular cartilage. Hypertrophy of cells and organelles, and cell replication were considered as signs of reparative processes. The accumulation of fine intracytoplasmic filaments (FIF) in chondrocytes, regarded as a sign of cell degeneration, was reduced in the exercise group. FIF also decreased in the deep zone chondrocytes of the immobilized group, which could be indicative of improved or retained viability of the chondrocytes. 相似文献
5.
Petri S. Mattila Jan Schugk Hongyan Wu Olli Mkel 《European journal of immunology》1995,25(9):2578-2582
During the initial stages of B lymphocyte differentiation heavy chain variable (VH), diversity (DH) and joining (JH) gene segments recombine to form a functional heavy chain variable region (VDJ) gene. Evidence for genetic polymorphism of the human JH gene segments has been obtained from mature rearranged VDJ sequences. We conducted an analysis of the published rearranged JH gene sequences and found that the JH alleles present in the two published germ-line JH region sequences were rare (approx. 2%) in the rearranged sequences. As an attempt to explain this discrepancy a 2.5-kb strech of DNA containing all the six heavy chain JH region genes and the most 3' DH gene segment, DHQ52, was amplified by the polymerase chain reaction from 39 individuals and analyzed for restriction fragment length polymorphism. Five new JH region haplotypes were found and sequenced. These new haplotypes contained the coding segment alleles that were frequent in antibody genes. Surprisingly, a high number of interallelic differencies in the non-coding sequence was found between the new and the two previously published haplotypes implying that the haplotypes had been separated early in evolution. In this respect the JH locus resembles HLA loci. 相似文献
6.
Differences in DNA-fingerprints between remission and relapse in childhood acute lymphoblastic leukemia 总被引:1,自引:0,他引:1
DNA "fingerprint" (DNA-F) analysis, based on the polymorphism caused by numeric variations in the tandem repeats of minisatellite areas of the human genome, has a potential capacity to reveal even minor genomic changes. In this study we have applied DNA-F to the detection of residual disease in leukemia. In order to identify normal and leukemic cell populations, we used two molecular probes: Jeffrey's minisatellite probes and M13 wild type phage probe, which detect different sets of polymorphic fragments in the human genome. Comparison of varying minisatellite fragments between remission and relapse was performed by Southern blot hybridization in seven patients with acute lymphoblastic leukemia (ALL). The results suggest that Southern hybridization with DNA "fingerprint" probes can prove to be a sensitive method in the detection of minimal residual disease in ALL. 相似文献
7.
HEALTH CARE RESEARCH: WHAT IS IT ABOUT? 总被引:1,自引:0,他引:1
8.
Several V genes participate in the early phenyloxazolone response in various combinations 总被引:4,自引:0,他引:4
Seventeen monoclonal anti-2-phenyloxazolone antibodies from the early (day 7) primary response were partially sequenced with an mRNA method. Ten antibodies expressed the VH-Ox1 gene. The remaining seven express at least four but probably six different germ-line VH genes belonging to Dildrop's groups 1, 5, 6 and 7 (Immunol. Today 1984. 5: 85). Two of them have been met before in other antibodies, one (group 6) in J606 and the other (group 7) in antibodies to the influenza virus hemagglutinin. Eleven kappa chains were partially sequenced and five of them (all VH-Ox1 antibodies) express the V kappa-Ox1 gene. One expresses another germ-line gene of the V kappa-Ox1 family, one the V kappa 89.4 gene, three the V kappa 45.1 gene and one a new V kappa gene. The V kappa 45.1 gene was found to form anti-phOx antibodies with two new VH genes. The frequency of somatic mutations in day 7 antibodies was estimated by comparing germ-line sequences and antibody sequences. It is low (one mutation per 2500 nucleotides sequenced), twenty times lower than in antibodies obtained a week later. Two anti-idiotype antisera (495 and 260) are useful in the typing of monoclonal antibodies. 260 bound only to antibodies coded by both VH-Ox1 and V kappa-Ox1 genes. 495 bound strongly to antibodies coded by the VH-Ox1 gene and weakly to antibodies coded by the (related) VH101 gene regardless of the light chain partner. 相似文献
9.
Korhonen RK Wong M Arokoski J Lindgren R Helminen HJ Hunziker EB Jurvelin JS 《Medical engineering & physics》2002,24(2):99-108
Indentation testing is a widely used technique for nondestructive mechanical analysis of articular cartilage. Although cartilage shows an inhomogeneous, layered structure with anisotropic mechanical properties, most theoretical indentation models assume material homogeneity and isotropy. In the present study, quantitative polarized light microscopy (PLM) measurements from canine cartilage were utilized to characterize thickness and structure of the superficial, collageneous tissue layer as well as to reveal its relation to experimental indentation measurements. In addition to experimental analyses, a layered, transversely isotropic finite element (FE) model was developed and the effect of superficial (tangential) tissue layer with high elastic modulus in the direction parallel to articular surface on the indentation response was studied. The experimental indentation stiffness was positively correlated with the relative thickness of the superficial cartilage layer. Also the optical retardation, which reflects the degree of parallel organization of collagen fibrils as well as collagen content, was related to indentation stiffness. FE results indicated effective stiffening of articular cartilage under indentation due to high transverse modulus of the superficial layer. The present results suggest that indentation testing is an efficient technique for the characterization of the superficial degeneration of articular cartilage. 相似文献
10.
Estimation of genetic risk for type 1 diabetes 总被引:8,自引:0,他引:8
Ilonen J Sjöroos M Knip M Veijola R Simell O Akerblom HK Paschou P Bozas E Havarani B Malamitsi-Puchner A Thymelli J Vazeou A Bartsocas CS 《American journal of medical genetics》2002,115(1):30-36
The most important gene loci defining risk of type 1 diabetes mellitus (T1DM) are located within the HLA gene region. HLA-DQ molecules are of primary importance but HLA-DR gene products modify the risk conferred by HLA-DQ. The risk associated with an HLA genotype is defined by the particular combination of susceptible and protective alleles. The highest risk is associated with a combination of two different risk haplotypes (7% risk to develop T1DM in Finland) whereas protective genotypes covering 69% of population have a risk of less than 0.2%). The complicated analysis of HLA genotypes is simplified by strong linkage disequilibrium between HLA-DRB1, -DQA1 and -DQB1 loci. In many cases one can deduce the alleles of other loci based on determination of the alleles in one locus. Differences between various populations in the frequency of marker alleles and in the linkages between them has to be taken into account. We have developed PCR based typing methods that utilize blood spot samples, microtiter plate format and lanthanide labeled oligonucleotide probes to define HLA-DQ and -DR alleles relevant for T1DM risk. Typing is run stepwise so that after initial HLA-DQB1 typing only those samples will be further analyzed in which -DQA1 or -DRB1 typing is informative and expected to contribute to the risk estimation. This method has been used to screen more than 50,000 newborn infants in Finland over a time period of 6 years, and it has been able to identify most children who have developed T1D during the follow-up period. The efficiency of the procedure has also been tested in Finnish and Greek populations. 相似文献