全文获取类型
收费全文 | 231616篇 |
免费 | 15801篇 |
国内免费 | 52篇 |
专业分类
247469篇 |
出版年
2021年 | 1914篇 |
2019年 | 1828篇 |
2018年 | 3294篇 |
2017年 | 3215篇 |
2016年 | 3971篇 |
2015年 | 3648篇 |
2014年 | 4881篇 |
2013年 | 6873篇 |
2012年 | 8135篇 |
2011年 | 8602篇 |
2010年 | 6160篇 |
2009年 | 5242篇 |
2008年 | 7625篇 |
2007年 | 7876篇 |
2006年 | 7517篇 |
2005年 | 7079篇 |
2004年 | 7205篇 |
2003年 | 6911篇 |
2002年 | 6836篇 |
2001年 | 9342篇 |
2000年 | 9000篇 |
1999年 | 7066篇 |
1998年 | 2192篇 |
1997年 | 2014篇 |
1996年 | 1882篇 |
1992年 | 5517篇 |
1991年 | 5711篇 |
1990年 | 5691篇 |
1989年 | 5662篇 |
1988年 | 5246篇 |
1987年 | 4893篇 |
1986年 | 4479篇 |
1985年 | 4698篇 |
1984年 | 3736篇 |
1983年 | 3055篇 |
1982年 | 2050篇 |
1980年 | 1758篇 |
1979年 | 3364篇 |
1978年 | 2601篇 |
1977年 | 2396篇 |
1976年 | 2354篇 |
1975年 | 2851篇 |
1974年 | 3133篇 |
1973年 | 3101篇 |
1972年 | 2757篇 |
1971年 | 2622篇 |
1970年 | 2223篇 |
1969年 | 2168篇 |
1968年 | 2039篇 |
1967年 | 1806篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
171.
The use of the probiotic Acylact in combination with Viferone containing human recombinant interferon-alpha 2 in the treatment of intestinal dysbacteriosis in children with insulin-dependent diabetes mellitus (IDDM) was shown to be highly efficient. Elimination of microecologic disorders in the intestine was accompanied in all the children by immune rearrangements. The quantity of secretory and serum immunoglobulins and complement increased and the white blood cell chemiluminescence proved to be higher. The correction of the immune status of the children with IDDM resulted in a certain decrease of glycemia. The data are indicative of the fact that such a treatment of intestinal dysbacteriosis in children with IDDM is promising. 相似文献
172.
173.
A new micronucleus test using peripheral blood erythrocytes of the newt Pleurodeles waltl to detect mutagens in fresh-water pollution 总被引:4,自引:0,他引:4
A model micronucleus test system using peripheral blood erythrocytes from larvae of Pleurodeles waltl is described. The most suitable larval stage for testing chemical treatments was determined. Larvae were reared in water containing one of the 4 compounds: benzo[a]pyrene (BaP), ethyl methanesulphonate (EMS), diethyl sulphate (DES) and N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). Response curves as a function of treatment duration over a period of 16 days were plotted for 3 different concentrations of the 4 compounds in order to optimize conditions for a low dose micronucleus test. This model can be used as a monitoring system for the detection of fresh water pollution and can also be employed for clastogen screening of chemical compounds. The test is sensitive, reliable and easy to use. 相似文献
174.
175.
176.
E Lendaro R Ippoliti A Brancaccio A Bellelli B Vallone G Ivaldi G V Sciarratta C Castello S Tomova M Brunori 《Biochimica et biophysica acta》1992,1180(1):15-20
Hemoglobin Dallas, an alpha-chain variant with a substitution of lysine for asparagine at position 97(G4), was found to have increased oxygen affinity (p1/2 = 1 mmHg at pH 7.3 and 20 degrees C), diminished cooperativity (n, the Hill coefficient = 1.7) and reduced Bohr effect (about 50%). Addition of allosteric effectors (such as 2,3-diphosphoglycerate, inositol hexakisphosphate and bezafibrate) led to a decrease in oxygen affinity and increase in cooperative energy. Kinetic studies at pH 7.0 and 20 degrees C revealed that (i), the overall rate of oxygen dissociation is 1.4-fold slower than that for HbA and (ii), the carbon monoxide dissociation rate is unaffected. The abnormal properties of this hemoglobin variant can be attributed to a more 'relaxed' T-state. 相似文献
177.
A F Frolov V E Rychnev V M Frolov M A Bala 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(11):93-96
The dynamics of circulating immune complexes (CIC) in comparison with the level of SH-groups of serum deproteinate and other characteristics of cell-mediated and humoral immunity (the reaction of the inhibition of antibodies, the levels of T-cells and their main subpopulations) was studied in 103 erysipelas patients and in 46 persons having had the disease at the acute period of this infection and at the periods between relapses. The elevated levels of CIC and SH-groups of serum deproteinate were found to be directly correlated with the inhibition index. The study showed that, as a rule, in patients with the elevated level of CIC the frequently relapsing form of erysipelas, accompanied by the formation of relative hypersuppressor-type secondary immunodeficiency and by a decrease in the functional activity of dermal macrophages, was observed. 相似文献
178.
179.
L F Adigamov L I Smirnova V D Nifontov M P Chernikov 《Biulleten' eksperimental'no? biologii i meditsiny》1985,99(6):687-689
The levels of thyroid, pituitary and steroid hormones-thyroxine, triiodothyronine and 11-hydroxycorticosteroids in the blood serum, somatotropin in the pituitary, and processes of protein assimilation were studied in rats in the early postnatal period. The highest endogenous production of thyroxine, triiodothyronine and somatotropin was detected in 15-day-old rats. The highest level of protein utilization was detected in 7 to 15-day-old rats, followed by the lowering of the utilization on changing over to definitive nutrition. Endogenous production of the anabolic hormones thyroxine, triiodothyronine and somatotropin was found to correlate with a high level of protein utilization in rats within the first days of life after birth. 相似文献
180.