全文获取类型
收费全文 | 82694篇 |
免费 | 1895篇 |
国内免费 | 45篇 |
专业分类
84634篇 |
出版年
2018年 | 884篇 |
2017年 | 1064篇 |
2016年 | 2785篇 |
2015年 | 6122篇 |
2014年 | 5713篇 |
2013年 | 5444篇 |
2012年 | 4625篇 |
2011年 | 1890篇 |
2010年 | 2000篇 |
2009年 | 1967篇 |
2008年 | 477篇 |
2007年 | 437篇 |
2006年 | 476篇 |
2005年 | 6584篇 |
2004年 | 5281篇 |
2003年 | 3494篇 |
2002年 | 1057篇 |
2001年 | 1074篇 |
2000年 | 310篇 |
1999年 | 1459篇 |
1998年 | 326篇 |
1997年 | 162篇 |
1992年 | 1922篇 |
1991年 | 2008篇 |
1990年 | 2070篇 |
1989年 | 1996篇 |
1988年 | 1953篇 |
1987年 | 1810篇 |
1986年 | 1623篇 |
1985年 | 1653篇 |
1984年 | 1089篇 |
1983年 | 834篇 |
1982年 | 459篇 |
1981年 | 420篇 |
1980年 | 370篇 |
1979年 | 1075篇 |
1978年 | 766篇 |
1977年 | 610篇 |
1976年 | 629篇 |
1975年 | 873篇 |
1974年 | 995篇 |
1973年 | 1005篇 |
1972年 | 953篇 |
1971年 | 929篇 |
1970年 | 820篇 |
1969年 | 832篇 |
1968年 | 735篇 |
1967年 | 751篇 |
1966年 | 584篇 |
1965年 | 432篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
K Gromysz-Ka?kowska E Szubartowska E Kaczanowska 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1989,92(1):89-93
1. Testosterone reduces the haemolytic action of Ekatin on the morphotic blood elements by accelerating maturation of erythroblastic cells. 2. Testosterone, by accelerating the metabolism of the pesticide causes a defective defence processes of the organism by decreasing the number of macrophages. 3. Intoxication of androgenised birds with Ekatin leads to a breakdown of the systemic adaptive mechanisms by rapid and early switching on the adrenal cortex in response to the stress caused by poisoning. 相似文献
182.
E A Serbinova R A Bakalova Ts S Sto?chev V E Kagan 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(10):419-421
The efficacy of lipid peroxidation inhibition by the natural antioxidant alpha-tocopherol and 2,2,5,7,8-pentamethyl-6-hydroxy-chromane (PMC), a derivative without hydrocarbon tail, as well as by the synthetic antioxidant 4-methyl-2,6-diterbutyl phenol (BHT) and its phospholipid derivative was studied in the membranes of rat liver microsomes and mitochondria. The presence of hydrocarbon tail in the antioxidant molecule determines the decrease of antioxidant efficiency in biomembranes. PMC and BHT exert a destructive effect on biomembranes, leading to an increase in their permeability to ions. This evidence suggests that the presence of hydrocarbon tail in the molecules of natural antioxidants provides not only for a relatively high antioxidant efficiency but also for a structural stability of biomembranes. 相似文献
183.
184.
W Brandst?dter 《Folia haematologica (Leipzig, Germany : 1928)》1982,109(6):843-848
A report is presented on the results of investigations made in 188 657 prospective blood donors from 1974-1980 within the district of Magdeburg. Methods of investigation and recommendations of the International Society of Blood Transfusion for selecting blood donors are compared. A total of 12337 (= 6.53%) were not admitted as a donor and 1360 blood conserves (0.77%) could not be used for transfusion because of laboratory findings obtained afterwards. Causes are dealt with in detail. The necessity of supervising the health of donors and the existing limitations for it are pointed out. 相似文献
185.
186.
Maximal oxygen uptake, anthropometry and physical activity in a randomly selected sample of 8 and 13 year old children in Sweden 总被引:1,自引:0,他引:1
J Sunneg?rdh L E Bratteby 《European journal of applied physiology and occupational physiology》1987,56(3):266-272
Maximal oxygen uptake was assessed in 101 randomly selected 8 and 13 year old children. In both age groups a significantly higher aerobic capacity was found in boys than in girls, both in absolute terms and when maximal oxygen uptake was related to body weight, lean body mass and lean leg volume. Among girls, maximal oxygen uptake per kg body weight was lower in the older than in the younger (p less than 0.05). Estimation of spontaneous physical activity, by means of a questionnaire and the actometry method, indicated that physical activity was greater in children with a high than in those with a low aerobic capacity. 相似文献
187.
Stimulation of secretion in exocrine secretory glands leads to the phosphorylation of a 22-kDa membrane protein (protein III) whose function is still unknown [Jahn et al. (1980) Eur. J. Biochem. 112, 345-352; Jahn & S?ling (1980) Proc. Natl Acad. Sci. USA 78, 6903-6906]. This report describes the comparison of this protein with phosphorylated membrane proteins of similar molecular mass in platelets and liver. Incubation of platelets with agents which raise the intracellular cAMP concentration results in the phosphorylation of a 22-kDa protein which is also phosphorylated in membrane preparations by endogenous kinases or by exogenous cAMP-dependent protein kinase. It is shown that this protein is distinct from protein III although both proteins have the same molecular mass and are substrates of cAMP-dependent protein kinase. In contrast to platelets, protein III could be demonstrated in liver microsomes. This indicates that the function of protein III is not exclusively linked to the stimulus-secretion coupling in exocrine cells. 相似文献
188.
A G Chuchalin V A Babushkina V Ia Arion R D Aspetov T B Sha?khinova 《Biulleten' eksperimental'no? biologii i meditsiny》1984,98(7):76-78
A study was made of the effect of T-activin on the biosynthesis of immune gamma-interferon. It was shown that in 27% of patients with chronic nonspecific pulmonary diseases, production of gamma-interferon by lymphocytes was substantially reduced during exacerbation of inflammatory process in the lungs. It was discovered that T-activin was not an interferon inductor but enhanced its synthesis in patients with a low capacity of producing immune interferon even at small doses of interferon inductor. The preparation does not produce any effect on this process in normal subjects and in patients showing the normal level of gamma-interferon. Thus T-activin can be used for stimulation of interferonogenesis. 相似文献
189.
190.