全文获取类型
收费全文 | 1795篇 |
免费 | 147篇 |
国内免费 | 2篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 32篇 |
2020年 | 9篇 |
2019年 | 29篇 |
2018年 | 46篇 |
2017年 | 32篇 |
2016年 | 51篇 |
2015年 | 87篇 |
2014年 | 78篇 |
2013年 | 119篇 |
2012年 | 145篇 |
2011年 | 120篇 |
2010年 | 83篇 |
2009年 | 75篇 |
2008年 | 95篇 |
2007年 | 133篇 |
2006年 | 112篇 |
2005年 | 104篇 |
2004年 | 114篇 |
2003年 | 110篇 |
2002年 | 92篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 21篇 |
1998年 | 32篇 |
1997年 | 25篇 |
1996年 | 9篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 10篇 |
1978年 | 2篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有1944条查询结果,搜索用时 27 毫秒
21.
22.
23.
24.
25.
26.
Bernard Rousset Chantal Poncet Rene Mornex 《Biochimica et Biophysica Acta (BBA)/General Subjects》1976,437(2):543-561
Isolated thyroid cells prepared from hog thyroid glands by tryptic dispersion were incubated with 131I− for 1–6 h. Free [131I]thyroxine was identified in the incubation medium by three chromatographic methods. Neither [131I]iodotyurosines nor [131I]triiodothyronine were detected. The [131I]thyroxine released in the medium by 100 μl of cells (packed cell volume) after a 6-h incubation period amounted to 1.16% (S.E. = ± 0.39) of the total radioactivity. The medium [131I]thyroxine represented 15–25% of the total [131I]thyroxine synthesized during the 6 h of incubation. Thyrotropin, 1–60 munits/ml, increased the medium [131I]thyroxine content 2–4 fold. Dibutyryl cyclic AMP mimicked the effect of thyrotropin. The amount of medium [131I]thyroxine was strictly related to the amount of incubated cells but was independent of the volume of the incubation medium. When prelabeled cells were incubated in the presence of methimazole the increase in medium [131I]thyroxine was quantitatively related to a decrease in the intracellular [131I]thyroxine. Addition of dinitrotyrosine, an inhibitor of the deiodinase activity, induced the release of iodotyrosines in the incubation medium. That the incubation supernatant of isolated thyroid cells did contain free thyroxine but no iodotyrosines suggests that the normal mechanisms of proteolysis of thyroglobulin and deiodination of iodotyrosines inside the cells are preserved. From these data, it was concluded that the thyroxine release by isolated cells represents a real secretion. 相似文献
27.
Chantal N. van Dijk Merel van Witteloostuijn Nada Vasi? Sergey Avrutin Elma Blom 《PloS one》2016,11(3)
When sending text messages on their mobile phone to friends, children often use a special type of register, which is called textese. This register allows the omission of words and the use of textisms: instances of non-standard written language such as 4ever (forever). Previous studies have shown that textese has a positive effect on children’s literacy abilities. In addition, it is possible that children’s grammar system is affected by textese as well, as grammar rules are often transgressed in this register. Therefore, the main aim of this study was to investigate whether the use of textese influences children’s grammar performance, and whether this effect is specific to grammar or language in general. Additionally, studies have not yet investigated the influence of textese on children’s cognitive abilities. Consequently, the secondary aim of this study was to find out whether textese affects children’s executive functions. To investigate this, 55 children between 10 and 13 years old were tested on a receptive vocabulary and grammar performance (sentence repetition) task and various tasks measuring executive functioning. In addition, text messages were elicited and the number of omissions and textisms in children’s messages were calculated. Regression analyses showed that omissions were a significant predictor of children’s grammar performance after various other variables were controlled for: the more words children omitted in their text messages, the better their performance on the grammar task. Although textisms correlated (marginally) significantly with vocabulary, grammar and selective attention scores and omissions marginally significantly with vocabulary scores, no other significant effects were obtained for measures of textese in the regression analyses: neither for the language outcomes, nor for the executive function tasks. Hence, our results show that textese is positively related to children’s grammar performance. On the other hand, use of textese does not affect—positively nor negatively—children’s executive functions. 相似文献
28.
Michael Haley Chantal Parent Xizhong Cui Andre Kalil Yvonne Fitz Rosaly Correa-Araujo Charles Natanson Robert L Danner Steven M Banks Peter Q Eichacker 《Journal of applied physiology》2005,98(6):2155-2162
Both route and severity of infection may influence immunomodulator agents in sepsis. We studied the effect of each variable on HRL-3, an L-selectin-directed MAb that inhibits neutrophil function, in a rat sepsis model. Animals (n = 800) were randomized to be treated with either HRL-3 or placebo and to receive Escherichia coli either intravenously (IV) or intrabronchially (IB) in doses producing low or high mortality rates. Animals received antibiotics and were observed for 168 h. Route but not dose of E. coli altered the effects HRL-3 on mortality rate (mean hazards ratio +/- SE). With IV E. coli, compared with control, HRL-3 was beneficial and reduced the hazards ratio both early (0 to 6 h; -0.75 +/- 0.23) and late (6 to 168 h; -0.72 +/- 0.36) (P = 0.001 and 0.04, respectively, over all E. coli doses). In contrast, with IB E. coli HRL-3 reduced the hazards ratio early (-1.1 +/- 0.36) but worsened it late (0.87 +/- 0.23) (P = 0.002 for both effects over all E. coli doses) in patterns significantly different from IV E. coli (P < 0.0001). Compared with control, although HRL-3 did not alter lung neutrophil numbers or injury score at 6 or 168 h with IV E. coli (P = ns for all), it reduced both early and increased them late with IB E. coli (P = 0.05 for all comparing 6 with 168 h). Thus immunomodulators inhibiting neutrophil function, although potentially beneficial with sepsis due to intravascular infection, may be harmful with extravascular infection regardless of severity. 相似文献
29.
30.