全文获取类型
收费全文 | 179216篇 |
免费 | 12436篇 |
国内免费 | 32篇 |
专业分类
191684篇 |
出版年
2023年 | 982篇 |
2022年 | 1187篇 |
2021年 | 2480篇 |
2020年 | 2018篇 |
2019年 | 2316篇 |
2018年 | 4468篇 |
2017年 | 4072篇 |
2016年 | 5556篇 |
2015年 | 7754篇 |
2014年 | 8217篇 |
2013年 | 10913篇 |
2012年 | 12909篇 |
2011年 | 12050篇 |
2010年 | 7982篇 |
2009年 | 6350篇 |
2008年 | 9830篇 |
2007年 | 9612篇 |
2006年 | 8919篇 |
2005年 | 8036篇 |
2004年 | 7714篇 |
2003年 | 7006篇 |
2002年 | 6506篇 |
2001年 | 4035篇 |
2000年 | 3906篇 |
1999年 | 3307篇 |
1998年 | 1580篇 |
1997年 | 1232篇 |
1996年 | 1137篇 |
1995年 | 1115篇 |
1994年 | 1009篇 |
1993年 | 856篇 |
1992年 | 2030篇 |
1991年 | 1853篇 |
1990年 | 1678篇 |
1989年 | 1601篇 |
1988年 | 1475篇 |
1987年 | 1323篇 |
1986年 | 1207篇 |
1985年 | 1250篇 |
1984年 | 1136篇 |
1983年 | 915篇 |
1982年 | 768篇 |
1981年 | 672篇 |
1980年 | 624篇 |
1979年 | 905篇 |
1978年 | 732篇 |
1977年 | 619篇 |
1975年 | 709篇 |
1974年 | 773篇 |
1973年 | 770篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
L Chrobák D Radochová K Smetana F Mat?ja M Kout J Polák P Dít? J Pribrosky I Dvorácková 《Folia haematologica (Leipzig, Germany : 1928)》1980,107(4):628-640
These siblings of a Czech family aged 21, 19 and 6 years, respectively, with congenital dyserythropoietic anemia, type II, (HEMPAS) are reported. In two elder siblings ferrokinetic studies revealed a rapid plasma 59Fe clearance, markedly decreased erythrocyte incorporation and shortened 51Cr red-cell survival. Direct anti-globulin test was found positive in one of them. Further investigations revealed low values of blood plasma cholesterol, total lipids, beta-lipoproteins, beta-carotine and vitamin E and A as well as low values of the prothrombin complex. Liver biopsy demonstrated siderosis and disseminated intravascular coagulation in the liver in both patients. The possible reasons for these humoral aberrations are discussed. 相似文献
43.
44.
D J Méwissen J H Rust J Rust 《Comptes rendus des séances de la Société de biologie et de ses filiales》1987,181(4):439-444
A total of 2,377 C 57 Bl/6M mice were assigned to control groups and experimental groups exposed to tritiated water administered as a pulse injection or in drinking water, at a dose of 1.0 microCi per injection or per ml of drinking water. Weanlings were observed for the duration of life span. Data analysis was based on two coefficient estimates (1) individual carcinogenic induction coefficient and (2) specific tumorigenic induction coefficient. The carcinogenic potency of tritium was found to be dual in nature in enhancing the absolute induction of lymphocytic lymphomas in both sexes as well as their relative induction in competition with reticulo-endothelial tumors of other types. 相似文献
45.
46.
47.
B Alexandre F Thiébaut M Allary E Boschetti C Séné J Saint-Blancard 《Revue fran?aise de transfusion et immuno-hématologie》1987,30(1):57-66
In this work the human plasma fibronectin was purified by affinity chromatography using a tandem column system. The first affinity column was filled with gelatin-Trisacryl whereas the second one contained heparin-Trisacryl. This double affinity chromatography demonstrated its high efficiency in term of purity and yield. Several analytical methods (electrophoresis, immunoelectrophoresis, F.P.L.C. and adhesion assay on cultured eucaryotic cells) evidenced in fact the high purity of the preparation as well as its biological behaviour in term of cell adhesion and spreading. The performances of the sorbents used facilitate the scaling up when large quantities of FNP are needed. 相似文献
48.
F Krizsa Z Borbényi E Arokszállásy I Cserháti 《Folia haematologica (Leipzig, Germany : 1928)》1980,107(4):683-687
The thrombopoietic serum activity was examined in rats during thrombocytopenia produced by bleeding or after treatment with antithrombocyte serum (ATS). 6 hours after both treatments the thrombopoietic activity of the serum, i.e. its content of thrombopoietin, is increased. After the ATS treatment of nephrectomized animals a similar increase of thrombopoietic activity as in normal animals could be achieved. In contrast to that, no similar increase of thrombopoietic activity was observed in nephrectomized animals after blood loss. According to the results of the authors the increase of thrombopoietic activity produced by different stimuli can be attributed to different mechanisms. 相似文献
49.
50.