全文获取类型
收费全文 | 8048篇 |
免费 | 33篇 |
国内免费 | 36篇 |
专业分类
系统科学 | 77篇 |
丛书文集 | 57篇 |
教育与普及 | 4篇 |
理论与方法论 | 73篇 |
现状及发展 | 4284篇 |
研究方法 | 463篇 |
综合类 | 3032篇 |
自然研究 | 127篇 |
出版年
2018年 | 69篇 |
2017年 | 70篇 |
2016年 | 71篇 |
2013年 | 58篇 |
2012年 | 179篇 |
2011年 | 299篇 |
2010年 | 87篇 |
2008年 | 203篇 |
2007年 | 206篇 |
2006年 | 209篇 |
2005年 | 200篇 |
2004年 | 191篇 |
2003年 | 166篇 |
2002年 | 176篇 |
2001年 | 194篇 |
2000年 | 202篇 |
1999年 | 131篇 |
1992年 | 114篇 |
1991年 | 90篇 |
1990年 | 94篇 |
1989年 | 77篇 |
1988年 | 63篇 |
1987年 | 100篇 |
1986年 | 86篇 |
1985年 | 152篇 |
1984年 | 101篇 |
1983年 | 79篇 |
1982年 | 89篇 |
1981年 | 78篇 |
1980年 | 99篇 |
1979年 | 212篇 |
1978年 | 191篇 |
1977年 | 222篇 |
1976年 | 142篇 |
1975年 | 170篇 |
1974年 | 236篇 |
1973年 | 190篇 |
1972年 | 202篇 |
1971年 | 219篇 |
1970年 | 314篇 |
1969年 | 245篇 |
1968年 | 205篇 |
1967年 | 251篇 |
1966年 | 199篇 |
1965年 | 135篇 |
1964年 | 61篇 |
1959年 | 74篇 |
1958年 | 91篇 |
1957年 | 88篇 |
1954年 | 59篇 |
排序方式: 共有8117条查询结果,搜索用时 62 毫秒
961.
Summary Three alicyclic organic phosphonium salts with an oxo and a morpholino group were found to exhibit a substantial antiarrhythmic action. The different activity levels were tentatively related to the structural modifications that they could induce in the cardiac cell membrane.Acknowledgment. We thank M. Adamantidis for the pharmacological testing. 相似文献
962.
F Delbarre C Mery J P Nakache A de Géry C Chastang 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,287(10):967-970
Comparison of 5 antiinflammatory drugs and placebo in a double blind, short term, cross-over trial conducted in patients suffering from rheumatoid arthritis. 15 measurements were used and studied. With classical unidimensional statistical tests it was not possible to discriminate active drugs between them. Multidimensional analysis (correspondance analysis and discriminant analysis) are more sensitive and allow us to distinguish active drugs with only 11 criterion. 相似文献
963.
H. -G. Meyer-Brunot A. Schweizer Béatrice Unterseh 《Cellular and molecular life sciences : CMLS》1980,36(4):389-391
Summary The content of blood in bone homogenates can be determined quantitatively by estimation of the haemin in the homogenate and in a sample of peripheral blood taken at the same time. Haem is completely split from the haemoglobin molecule by reaction with hydrochloric acid-acetone and converted to haemin, which can be analyzed spectrophotometrically. The blood content can be calculated from the amount of haemin in the homogenate in relation to that of the peripheral blood. This method is useful to determine the real amount of drugs in bone tissue.Acknowledgment. Thanks are due to Dr N. Walker and Dr H. Stuflesser, Balgrist, Orthopaedic University Hospital, Zürich, for kindly supplying the heads of femora removed at surgery. 相似文献
964.
A. Dobozy L. Kemény M. Csató J. Hunyadi A. Sz. Kenderessy N. Simon 《Cellular and molecular life sciences : CMLS》1984,40(12):1403-1404
Summary An enhancement effect of mouse erythrocyte rosette forming (MERF) cells on the production of migration inhibitory factor, chemotactic factor for neutrophils and skin reactive factor in T-lymphocyte cultures stimulated with the purified protein derivative of tuberculin was observed. We consider it likely that the MERF cells, possessing the appropriate cell surface constituents to construct an immunogenic moiety, present antigen on their surfaces to elicit lymphokine production.This work was supported by the Scientific Research Council, Ministry of Health, Hungary, Code No. 421030401 1/s 相似文献
965.
A. M. Bobst T. V. Wang P. A. Cerutti 《Cellular and molecular life sciences : CMLS》1981,37(6):597-598
Summary Scavenging studies are supporting the notion that triplet radical cations are formed during the binding of the carcinogen N-acetoxy-2-acetylamino-fluorene to native DNA in vitro.This work was supported by Grant No.3305.78 of the Swiss National Science Foundation and by a grant from The Roche Research Foundation. 相似文献
966.
A. Laubscher A. Pletscher C. G. Honegger J. G. Richards V. Colombo 《Cellular and molecular life sciences : CMLS》1979,35(8):1081-1083
Summary Myelin basic protein (MBP) isolated from bovine spinal cord caused a marked shape change reaction of human blood platelets which was not accompanied by the release reaction and not inhibited by methysergide and spiroperidol. Only those basic proteins, including MBP, which had previously shown to exert neuronal depolarisation also induced the shape change reaction. Therefore, these findings may extend the use of platelets as neuronal models.Acknowledgment. We thank Miss B. Gieux and Miss M. Handschin for skilful technical assistance. 相似文献
967.
The superior cervical ganglia of the rat have been incubated in vitro for 1 h in basal medium Eagle (BME) with Hanks' salts, BME with Earle's salts, Kreb's solution and NCTC 109 medium. Comparison of the cell areas, established by a semi-automatic quantitative method, shows that the three former induce a 30--35% neuronal retraction, whereas NCTC 109 has no effect. Thus this latter medium seems the best one for studies using incubation of these cells. 相似文献
968.
The distribution of fast, intermediate and slow renaturing fractions of Rhynchosciara americana DNA was examined in the polytene salivary gland chromosomes by in situ hybridization. Heterochromatic areas readily hybridized but hybrid formation in the euchromatin depended more on the repetitiveness of the RNA probe. 相似文献
969.
Summary In rats undergoing unilateral extirpation of the pelvic ganglion, the adrenergic innervation disappeared on the ipsilateral side of the urinary bladder. It had reappeared after 6–9 weeks.This work was supported by grants from the Faculty of Medicine in Lund to M.E. 相似文献
970.