全文获取类型
收费全文 | 4985篇 |
免费 | 205篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 150篇 |
妇产科学 | 109篇 |
基础医学 | 739篇 |
口腔科学 | 52篇 |
临床医学 | 360篇 |
内科学 | 716篇 |
皮肤病学 | 124篇 |
神经病学 | 391篇 |
特种医学 | 88篇 |
外科学 | 474篇 |
综合类 | 17篇 |
一般理论 | 2篇 |
预防医学 | 1122篇 |
眼科学 | 46篇 |
药学 | 521篇 |
中国医学 | 2篇 |
肿瘤学 | 264篇 |
出版年
2023年 | 29篇 |
2022年 | 70篇 |
2021年 | 124篇 |
2020年 | 84篇 |
2019年 | 95篇 |
2018年 | 121篇 |
2017年 | 89篇 |
2016年 | 102篇 |
2015年 | 112篇 |
2014年 | 130篇 |
2013年 | 201篇 |
2012年 | 271篇 |
2011年 | 283篇 |
2010年 | 147篇 |
2009年 | 124篇 |
2008年 | 187篇 |
2007年 | 205篇 |
2006年 | 212篇 |
2005年 | 188篇 |
2004年 | 199篇 |
2003年 | 183篇 |
2002年 | 169篇 |
2001年 | 108篇 |
2000年 | 100篇 |
1999年 | 79篇 |
1998年 | 26篇 |
1992年 | 74篇 |
1991年 | 61篇 |
1990年 | 66篇 |
1989年 | 68篇 |
1988年 | 53篇 |
1987年 | 68篇 |
1986年 | 66篇 |
1985年 | 74篇 |
1984年 | 48篇 |
1983年 | 44篇 |
1979年 | 60篇 |
1978年 | 53篇 |
1977年 | 33篇 |
1976年 | 25篇 |
1975年 | 26篇 |
1974年 | 71篇 |
1973年 | 54篇 |
1972年 | 52篇 |
1971年 | 56篇 |
1970年 | 60篇 |
1969年 | 51篇 |
1968年 | 46篇 |
1967年 | 50篇 |
1966年 | 45篇 |
排序方式: 共有5203条查询结果,搜索用时 0 毫秒
21.
Potent inhibition of HIV-1 entry by (s4dU)35 总被引:2,自引:0,他引:2
Horváth A Tokés S Hartman T Watson K Turpin JA Buckheit RW Sebestyén Z Szöllosi J Benko I Bardos TJ Dunn JA Fésüs L Tóth FD Aradi J 《Virology》2005,334(2):214-223
22.
Genetic variants of homocysteine metabolizing enzymes and the risk of coronary artery disease 总被引:2,自引:0,他引:2
Janosíková B Pavlíková M Kocmanová D Vítová A Veselá K Krupková L Kahleová R Krijt J Kraml P Hyánek J Zvárová J Andel M Kozich V 《Molecular genetics and metabolism》2003,79(3):167-175
It is unresolved whether elevated homocysteine in coronary artery disease (CAD) is the cause of arteriosclerosis or its consequence. In contrast, genetic variants of enzymes that metabolize homocysteine cannot be altered by arteriosclerosis. Consequently, their association with CAD would permit to imply causality. We modeled by regression analysis the effect of 11 variants in the methionine cycle upon CAD manifestation in 591 controls and 278 CAD patients. Among the examined variants only the carriership for the c.844ins68 in the cystathionine beta-synthase (CBS) gene was associated with a significantly lowered risk of CAD (OR=0.56; 95% CI=0.35-0.90 in the univariable, and OR=0.41, 95% CI=0.19-0.89 for obese people in the multivariable analysis, respectively). Healthy carriers of the c.844ins68 variant exhibited, compared to the wild type controls, significantly higher postload ratios of blood S-adenosylmethionine to S-adenosylhomocysteine (61.4 vs. 54.9, p=0.001) and of plasma total cysteine to homocysteine (8.6 vs. 7.3, p=0.004). The changes in these metabolites are compatible with an improved methylation status and with enhanced activity of homocysteine transsulfuration. In conclusion, the coincidence of clinical and biochemical effects of a common c.844ins68 CBS variant supports the hypothesis that compounds relating to homocysteine metabolism may play role in the development and/or progression of CAD. 相似文献
23.
24.
Lohm S Peduto-Eberl L Lagadec P Renggli-Zulliger N Dudler J Jeannin JF Juillerat-Jeanneret L 《Clinical & experimental metastasis》2005,22(4):341-349
It is recognised that stromal cells determine cancer progression. We have previously shown that active TGFβ produced by rat colon carcinoma cells modulated NO production in rat endothelial cells. To elucidate the role of TGFβ and NO in the mechanisms of interaction of colon carcinoma cells with stromal cells and in cancer progression, we transfected
REGb cells, a regressive colon carcinoma clone secreting latent TGFβ, with a cDNA encoding for a constitutively-secreted active TGFβ. Out of 20 injected rats only one tumour progressed, which was resected and sub-cultured (ReBeta cells). ReBeta cells secreted
high levels of active TGFβ. The adhesive properties of REGb and Rebeta cells to endothelial cells were similar, showing that the secretion of active
TGFβ is not involved in tumour cell adhesion to endothelial cells. ReBeta, but not REGb, cell culture supernatants inhibited cytokine-dependent
NO secretion by endothelial cells, but inhibition of NO production was similar in co-cultures of REGb or ReBeta cells with
endothelial cells. Therefore, secretion of active TGFβ regulated endothelial NO synthase activity when tumour cells were distant from, but not in direct contact with, endothelial
cells. However, only ReBeta cells inhibited cytokine-dependent secretion of NO in coculture with macrophages, indicating that
the active-TGFβ–NO axis confers an advantage for tumour cells in their interaction with macrophages rather than endothelial cells in cancer
progression. 相似文献
25.
Lafay-Cousin L Soenen V Mazingue F Preudhomme C Laï JL Andrieux J 《Cancer Genetics and Cytogenetics》2004,150(2):153-155
Recurrent chromosomal rearrangements involving the 11q23 region have been described in various hematologic malignancies. Among these rearrangements, translocations are the most common mechanism involving the mixed lineage leukemia gene (MLL). Few cases of insertion have been reported and, to our knowledge, none of them involved MLL and chromosome 1. We report a complex karyotype in a childhood acute myelomonocytic leukemia (AML M4) involving the 11q23 region with an insertion between chromosomes 1 and 11 in addition to a translocation between chromosomes 11 and 22. This translocation was clarified by fluorescence in situ hybridization (FISH) analysis: 46,XY,ins(1;11)(q22q23;q13q23),t(11;22)(q13;q11q12). This finding also underlines the complementary contribution of conventional cytogenetic and FISH analysis to detect karyotypic complex abnormalities. 相似文献
26.
Székely G. Lévai G. Matesz K. 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1983,53(1):109-117
In the frog solitarius nucleus, primary afferent terminals of the facial and glossopharyngeal-vagal nerves were identified with cobalt labelling and electron microscopy. The labelled terminals were grouped in two main categories, one with small (1-2 micron) and pale terminals, and another with large (3-5 micron) and dark terminals. The small terminals greatly outnumbered the large ones. In addition many terminals intermediate in size and staining reactions were found. All kinds of labelled boutons contained medium-size clear synaptic vesicles, among which dense-core vesicles of the smaller type frequently occurred. The labelled primary afferent terminals established axo-dendritic contacts of the asymmetric type. Close to these contact sites they were themselves very frequently contacted by a profile interpreted as presynaptic in relation to them. Such profiles contained spherical, pleomorphic (including dense-core) or flattened vesicles; a fourth kind was interpreted as presynaptic dendrites. It is concluded that viscerosensory fibres, as opposed to somatosensory fibres, predominantly generate small and lightly stained terminals. It is likely that the effect of synaptic transmission at the solitarius tract terminals is modulated in a very versatile manner by the various presynaptic profiles converging on these terminals. 相似文献
27.
The purpose of the study was to characterize the renal TxA2, PGI2 and PGF2 alpha release in response to arterial blood pressure (BP) fall induced by systemic and intrarenal vasorelaxation in subjects with essential hypertension. Significantly enhanced TxB2- and PGF2 alpha excretion and no change in ratio TxB2/6-keto-PGF1 alpha were found in urine in hypertensive patients after administration of the Ca++ entry blocker gallopamil, used to induce BP fall. This response was associated with significant PRA elevation in peripheral venous samples. In in vitro experiments, direct and indirect effects of gallopamil on renal tissue could be distinguished. Gallopamil resulted in significant diminution of TxA2 production and a decrease in TxB2/6-keto PGF1 alpha ratio in incubated rat kidney slices. This model was also used to test biochemically the effect of reflex sympathetic activation on prostanoid generation in kidney. It was concluded that this mechanism was only one among the indirect mechanisms by which gallopamil could induce that renal prostanoid response in hypertensive subjects. The response in urinary TxB2- and PGF2 alpha excretion was found to be significantly related to the changes in sodium reabsorption. These results suggested, that the increase in renal TxA2 and PGF2 alpha production in response to systemic and intrarenal "vasodilation" induced by gallopamil in hypertensive subjects can be interpreted as part of counteraction of the kidneys to BP fall. 相似文献
28.
L cells (L-As subline) have been adapted to a temperature of 4 degrees C. In the cold-adapted cells, designated LC3, greater amounts of infectious herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) were synthesized than in the original L-As cells or in another control L-cell line. Two strains of HSV-1 reached higher infectious titres in LC3 cells grown at 36 degrees C than in those grown at 32 degrees C. The HSV-2 strain tested replicated in LC-3 cells grown at 32 degrees C better than at higher temperature. Increased reproduction of HSV in LC3 cells was not due to enhanced adsorption of virions on the cells as compared with control L cells. The multiplication of cold-adapted LC3 cells was and was not more intensive than of L-As and control L cells, respectively. The virological results are confronted with known physiological properties of cold-adapted cells. 相似文献
29.
Interaction of heart glycosides and viruses 总被引:1,自引:0,他引:1
30.
Garaczi E Széll M Jánossy T Koreck A Pivarcsi A Buzás E Pos Z Falus A Dobozy A Kemény L 《International immunology》2004,16(12):1781-1788
Histamine plays an important role in the regulation of various immunological functions. To evaluate the role of histamine in contact hypersensitivity, contact dermatitis was induced with dinitrofluorobenzene (DNFB) in histidine decarboxylase knockout (HDC-/-) histamine-deficient and wild-type mice. The DNFB-induced increase of the ear thickness was significantly higher in HDC-/- mice than in wild-type mice. Using flow cytometry, significantly lower percentages of CD4+ Th and CD8+ Tc cells, and significantly higher percentages of CD45R+ B cells were observed in the regional lymph nodes in HDC-/- mice than in wild-type mice. In the ear specimens of both groups, the majority of the infiltrating cells were neutrophils and macrophages at 24 and 48 h after challenge. Using immunohistochemistry, we observed significantly more CD45+ leukocytes in HDC-/- mice than in wild-type mice. The expression of Th1 (IL-2, IFN-gamma, TNF-alpha) and Th2 (IL-4) mRNAs was examined by quantitative real time RT-PCR in the ear samples. The levels of Th1 cytokine mRNAs both at 24 and 48 h after challenge and IL-4 mRNA at 48 h showed a significantly higher increase in HDC-/- mice than in wild-type mice. These results suggest that histamine plays a negative immunoregulatory role in DNFB-induced contact hypersensitivity. 相似文献