全文获取类型
收费全文 | 23747篇 |
免费 | 2213篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 187篇 |
儿科学 | 888篇 |
妇产科学 | 710篇 |
基础医学 | 3282篇 |
口腔科学 | 554篇 |
临床医学 | 3200篇 |
内科学 | 4326篇 |
皮肤病学 | 276篇 |
神经病学 | 2212篇 |
特种医学 | 635篇 |
外科学 | 2375篇 |
综合类 | 490篇 |
一般理论 | 42篇 |
预防医学 | 3355篇 |
眼科学 | 435篇 |
药学 | 1425篇 |
中国医学 | 7篇 |
肿瘤学 | 1622篇 |
出版年
2023年 | 127篇 |
2022年 | 203篇 |
2021年 | 456篇 |
2020年 | 288篇 |
2019年 | 435篇 |
2018年 | 511篇 |
2017年 | 402篇 |
2016年 | 406篇 |
2015年 | 514篇 |
2014年 | 681篇 |
2013年 | 1062篇 |
2012年 | 1445篇 |
2011年 | 1546篇 |
2010年 | 848篇 |
2009年 | 724篇 |
2008年 | 1397篇 |
2007年 | 1456篇 |
2006年 | 1467篇 |
2005年 | 1406篇 |
2004年 | 1261篇 |
2003年 | 1188篇 |
2002年 | 1273篇 |
2001年 | 386篇 |
2000年 | 362篇 |
1999年 | 392篇 |
1998年 | 293篇 |
1997年 | 222篇 |
1996年 | 194篇 |
1995年 | 188篇 |
1994年 | 202篇 |
1993年 | 186篇 |
1992年 | 205篇 |
1991年 | 220篇 |
1990年 | 231篇 |
1989年 | 226篇 |
1988年 | 199篇 |
1987年 | 183篇 |
1986年 | 202篇 |
1985年 | 204篇 |
1984年 | 177篇 |
1983年 | 160篇 |
1982年 | 159篇 |
1981年 | 128篇 |
1980年 | 144篇 |
1979年 | 151篇 |
1978年 | 140篇 |
1977年 | 124篇 |
1975年 | 103篇 |
1974年 | 105篇 |
1973年 | 114篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
PTOV-1, a novel protein overexpressed in prostate cancer,shuttles between the cytoplasm and the nucleus and promotes entry into the S phase of the cell division cycle 下载免费PDF全文
Santamaría A Fernández PL Farré X Benedit P Reventós J Morote J Paciucci R Thomson TM 《The American journal of pathology》2003,162(3):897-905
PTOV1 was recently identified as a novel gene and protein during a differential display screening for genes overexpressed in prostate cancer. The PTOV1 protein consists of two novel protein domains arranged in tandem, without significant similarities to known protein motifs. By immunohistochemical analysis, we have found that PTOV1 is overexpressed in 71% of 38 prostate carcinomas and in 80% of samples with prostate intraepithelial neoplasia. High levels of PTOV1 in tumors correlated significantly with proliferative index, as assessed by Ki67 immunoreactivity, and associated with a nuclear localization of the protein, suggesting a functional relationship between PTOV1 overexpression, proliferative status, and nuclear localization. In quiescent cultured prostate tumor cells, PTOV1 localized to the cytoplasm, being excluded from nuclei. After serum stimulation, PTOV1 partially translocated to the nucleus at the beginning of the S phase. At the end of mitosis, PTOV1 exited the nucleus. Transient transfection of chimeric green fluorescent protein-PTOV1 forced the entry of cells into the S phase of the cell cycle, as shown by double fluorescent imaging for green fluorescent protein and for Ki67, and also by flow cytometry. This was accompanied by greatly increased levels of cyclin D1 protein in the transfected cells. These observations suggest that overexpression of PTOV1 can contribute to the proliferative status of prostate tumor cells and thus to their biological behavior. 相似文献
152.
153.
154.
Thomson KL Gloyn AL Colclough K Batten M Allen LI Beards F Hattersley AT Ellard S 《Human mutation》2003,22(5):417
Maturity-onset diabetes of the young (MODY) resulting from mutations in the glucokinase (GCK) gene accounts for approximately 20% of MODY in the UK. We have performed fluorescent single stranded conformation polymorphism (F-SSCP) analysis or direct sequencing of the GCK gene in 212 patients referred as part of a research cohort or for diagnostic molecular genetic testing. Mutation screening has identified 43 different mutations in 61 individuals, of which 21 are novel. This report details the mutations identified and their associated clinical features. 相似文献
155.
H. P. Friedl D. J. Smith G. O. Till P. D. Thomson D. S. Louis P. A. Ward 《The American journal of pathology》1990,136(3):491-495
We evaluated effluent blood from extremities of human patients undergoing reconstructive surgical treatment, which is routinely accompanied by upper-extremity exsanguination and application of a tourniquet, resulting in total interruption of arterial blood flow to one upper extremity. After tourniquet release (reperfusion), there were immediate increases in the plasma levels of xanthine oxidase activity, uric acid, and histamine in the ipsilateral limb and much smaller increases, if any, in levels of the same materials in plasma obtained from the contralateral extremity. There was no detectable xanthine dehydrogenase activity in plasma from either limb. Plasma also contained evidence of products consistent with the formation of oxygen-derived free radicals, namely, the appearance predominantly in the reperfused limb of hemoglobin and fluorescent compounds. These data indicate for the first time in humans that ischemia-reperfusion events are associated with the appearance of xanthine oxidase activity and its products in the plasma effluent. 相似文献
156.
Isaac Ginsburg Ruth Borinski Milu Sadovnic Yael Eilam Kim Rainsford 《Inflammation》1987,11(3):253-277
Poly-l-histidine (PHSTD) of molecular weight 26,000 induced the generation of large amounts of Superoxide (O
2
–
) and hydrogen peroxide (H2O2) in human neutrophils (PMNs). Despite its low solubility at neutral pH, PHSTD was bound very rapidly to the PMN surfaces. Maximal generation of O
2
–
took place with 4–5 ×10–6 M of PHSTD, starting after a lag of about 25 sec and proceeding for 15–17 min at a rate of 150 nmol/107 PMNs/min, suggesting that this polycation is one of the most potent stimulators of O
2
–
generation known, PHSTD was found to be non-toxic for PMNs even at millimolar concentrations. Generation of O
2
–
by PHSTD depended on extracellular calcium; it was inhibited by calcium channel blockers and by trifluoperazine, and it triggered a sharp rise in intracellular calcium as determined by the Quin 2 fluorescence technique. The generation of both O
2
–
and H2O2 by PHSTD was partially inhibited by cytochalasin B or (CYB, CYE). On the other hand, CYB markedly enhanced the generation of both O
2
–
and H2O2 following stimulation of PMNs either by PHSTD, polyarginine, histone, or by antibody-opsonized group A streptococci. Electron microscopic analysis and NBT reduction tests revealed that both PHSTD and PHSTD-opsonized streptococci were avidly phagocytosed by PMNs. Since CYB totally inhibited internalization of both PHSTD and the PHSTD-opsonized streptococci, it was suggested that these agents stimulated oxygen radical generation mainly on the leukocyte surfaces. Complexes (CX) formed between PHSTD and polyanethole sulfonate (a strong polyanion) or between histone and the polyanion mimicked immune CX in their ability to trigger the generation of large amounts of O
2
–
which were inhibited by CYB. Generation of O
2
–
and chemiluminescence either by PHSTD or by PHSTD-opsonized streptococci were markedly inhibited by poly-l-glutamate, suggesting that PHSTD acted as a cationic agent which interacted via electrostatic forces with some negatively charged sites in the leukocyte membrane. Generation of H2O2 by PHSTD was also markedly inhibited by deoxyglucose, KCN, DASA, as well as by the lipoxygenase inhibitors nordihydroguaiaretic acid, phenidone, and propylgallate. On the other hand, cyclooxygenase inhibitors such as aspirin, indomethacin, and piroxicam were inactive, suggesting that arachidonic acid metabolism via lipoxygenase pathway might have been involved in the activation by PHSTD of the NADPH oxidase in PMNs. PHSTD may mimic the effects of antibodies both as an opsonin and as a potent stimulator of the respiratory burst in PMNs and may thus serve as a model for further study of leukocyte-bacteria interactions in infectious and inflammatory sites and of the pathogenicity of immune complexes.Supported by a research grant from Dr. S. M. Robbins of Cleveland, Ohio. 相似文献
157.
Inhibition of contact sensitivity reactions to DNFB by topical cyclosporin application in the guinea-pig. 总被引:2,自引:1,他引:2 下载免费PDF全文
R D Aldridge A W Thomson R Rankin P H Whiting C Cunningham J G Simpson 《Clinical and experimental immunology》1985,59(1):23-28
Contact sensitivity skin reactions to dinitrofluorobenzene (DNFB) were inhibited by twice daily topical application of cyclosporin (CsA, 2%) in normal guinea-pigs and in those with enhanced contact sensitivity reactions following pre-treatment with cyclophosphamide. In contrast to oral administration of CsA (25 mg/kg) for 4 days, topical application of the drug over the same period did not result in systemic absorption (as measured by radioimmunoassay) or in any evidence of nephrotoxicity. 相似文献
158.
Summary Our previous studies have shown that a breakdown in tight junctions in the dystrophic retinal pigment epithelium (RPE) of Royal College of Surgeons' rats is accompanied by changes in intramembrane structure which suggest a redistribution of intramembrane particles. We have now investigated, using thep-nitrophenyl phosphate technique, the possibility that a specific membrane protein, Na-K-ATPase, is redistributed as tight junctions break down in the dystrophic RPE. In the normal RPE, Na-K-ATPase activity is restricted to the apical membrane. Junctional membranes and membranes around phagosomes are free of enzyme activity, suggesting a segregation of the transport enzyme from the Junctional and phagocytic membrane. In the dystrophic RPE, prior to changes in tight junctions, enzyme activity is restricted to the apical membrane. During the initial stages of Junctional breakdown, Junctional membranes and membranes around cytoplasmic inclusions are also labelled. As the breakdown progresses, Na-K-ATPase activity is often present laterally and basolaterally and is sometimes absent apically. Enzyme activity is seen basally only where RPE cells have detached from Bruch's membrane and are superimposed over each other. These changes suggest that Na-K-ATPase redistributes during junctional breakdown, but that attachments between the RPE and Bruch's membrane may restrict the redistribution. The apparent reduction of enzyme activity apically suggests that active transport across the dystrophic RPE may be reduced as the tight junctions break down. 相似文献
159.
Monoclonal Antibodies to Trypanosoma cruzi Inhibit Motility and Nucleic Acid Synthesis of Culture Forms 总被引:2,自引:1,他引:2 下载免费PDF全文
Maria Julia Manso Alves Masamichi Aikawa Ruth S. Nussenzweig 《Infection and immunity》1983,39(1):377-382
Monoclonal antibodies were raised against the surface of epimastigotes and metacylic trypomastigotes of Trypanosoma cruzi, as shown by electron microscopy, agglutination, and immunofluorescence. The antibodies were stage specific but not strain specific. A deleterious effect of the antibodies on T. cruzi culture forms was shown by the drastic reduction of parasite motility and incorporation of nucleic acid precursors. Some fraction of the parasite population, however, was viable and replicated and infected mouse macrophages in culture. The antibodies were found to also mediate complement-induced lysis of culture forms of T. cruzi. 相似文献
160.