全文获取类型
收费全文 | 4066篇 |
免费 | 267篇 |
国内免费 | 2篇 |
出版年
2022年 | 17篇 |
2021年 | 35篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 43篇 |
2017年 | 23篇 |
2016年 | 57篇 |
2015年 | 80篇 |
2014年 | 100篇 |
2013年 | 253篇 |
2012年 | 189篇 |
2011年 | 185篇 |
2010年 | 114篇 |
2009年 | 111篇 |
2008年 | 198篇 |
2007年 | 201篇 |
2006年 | 228篇 |
2005年 | 199篇 |
2004年 | 209篇 |
2003年 | 245篇 |
2002年 | 212篇 |
2001年 | 115篇 |
2000年 | 109篇 |
1999年 | 104篇 |
1998年 | 63篇 |
1997年 | 45篇 |
1996年 | 37篇 |
1995年 | 47篇 |
1994年 | 51篇 |
1993年 | 53篇 |
1992年 | 95篇 |
1991年 | 82篇 |
1990年 | 71篇 |
1989年 | 78篇 |
1988年 | 58篇 |
1987年 | 56篇 |
1986年 | 47篇 |
1985年 | 42篇 |
1984年 | 41篇 |
1983年 | 34篇 |
1982年 | 36篇 |
1981年 | 37篇 |
1980年 | 32篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 34篇 |
1976年 | 20篇 |
1975年 | 20篇 |
1974年 | 28篇 |
1970年 | 17篇 |
排序方式: 共有4335条查询结果,搜索用时 109 毫秒
31.
K Nagata K Hirayoshi M Obara S Saga K M Yamada 《The Journal of biological chemistry》1988,263(17):8344-8349
The synthesis of a major collagen-binding glycoprotein of molecular weight 47,000 was previously shown to be altered by malignant transformation as well as by heat shock in chick embryo fibroblasts (Nagata, K., and Yamada, K.M. (1986) J. Biol. Chem. 261, 7531-7536 and Nagata, K., Saga, S., and Yamada, K.M. (1986) J. Cell Biol. 103, 223-229). In this paper, we examined the synthesis of this heat shock protein (hsp47) in terms of possible functional precursors and its regulation after heat shock and transformation by Rous sarcoma virus. Actinomycin D inhibited the induction of hsp47 after heat shock. Messenger RNAs purified from chick embryo fibroblasts (CEF), heat-treated CEF, and transformed CEF were analyzed in an in vitro translation system. In vitro translated products readily bound to gelatin-Sepharose, and levels were increased after heat shock and decreased after transformation. The increase in mRNA after heat shock was shown more directly by Northern assay using a synthetic oligonucleotide probe. We identified two putative precursors of hsp47 using an in vitro translation/processing system and tunicamycin: one is a 42-kDa primary translation product and the second is a 41-kDa polypeptide lacking signal peptide and carbohydrate moieties. Both of these precursors are biologically active as determined by gelatin-binding activity, in contrast to the lack of binding activity of precursors in several other membrane-associated receptor systems. 相似文献
32.
A Yanai I Tange Y Bandoh K Tsuzuki H Sugino S Nagata 《Plastic and reconstructive surgery》1988,82(6):965-972
Our technique for the correction of cryptotia using both Z-plasty and the advancement flap is described. The main advantages are the simple design of the skin incision and the possibility of its application to cryptotia other than severe cartilage deformity and extreme lack of skin. 相似文献
33.
Summary Ring formed actin filaments were observed in tobacco BY-2 cells. The change of this structure during culture was followed by fluorescence microscopy. 相似文献
34.
35.
Comparative study on the distribution of six species of bitterling in a creek in Fukuoka Prefecture was carried out. The upper part of the creek was fluvial, and the lower part stagnant.Acheilognathus lanceolatus, A. tabira subsp. (b) of Nakamura (1969),A. rhombeus andRhodeus atremius showed wide distribution in the creek throughout their life.A. limbatus seemed to be a fluvial species, andR. ocellatus smithii a lentic species. In the spawning season, however, all the species of bitterling, exceptingR. o. smithii, probably possess a common spawning ground in which mussels occur at a relatively high density. Adult females ofA. lanceolatus, A. tabira subsp. (b) andR. atremius without ripe eggs aggregated in the lower, stagnant parts of the creek. Most juveniles of these species and ofA. rhombeus seemed to grow in the lower part of the creek, and then migrate upward untill their spawning season. No species among the same phylogenetic group has the same set of the life modes (spawning season, spawning sites, aggregation of females without ripe eggs in the lower part of the creek and probability of upstream migration of 0-year-old fish toward spawning sites). 相似文献
36.
37.
H-2RIIBP (RXR beta) heterodimerization provides a mechanism for combinatorial diversity in the regulation of retinoic acid and thyroid hormone responsive genes. 总被引:70,自引:10,他引:60
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M S Marks P L Hallenbeck T Nagata J H Segars E Appella V M Nikodem K Ozato 《The EMBO journal》1992,11(4):1419-1435
38.
Kojiro Kurisu Yasuyoshi Ohsaki Kengo Nagata Tetsuichiro Inai Toshio Kukita 《Cell and tissue research》1992,267(3):429-435
Summary In order to examine the intracellular distribution of precursors of type I and type III collagen and fibronectin in the palatal mesenchymal (MEPM) cells of the mouse embryo cultured under ascorbate-deficient conditions, immuno-electron-microscopic studies were carried out by use of affinity purified antibodies for these proteins. MEPM cells were obtained from the palatal shelves of 14-day-old mouse fetuses and cultured for 3–7 days in medium, either with or without 50 ng/dish/day ascorbic acid. Results obtained were as follows: (1) Although the rough endoplasmic reticulum (rER) of MEPM cells cultured for 5 days in ascorbate-supplemented medium was flattened, that in cells cultured in ascorbate-deficient medium had a distended or vesicular appearance. (2) Vesicular or distended rER showed heterogeneous staining for both type I and type III collagen, namely, some parts of rER showed positive staining for both types of collagen, while others showed negative staining. (3) Both type I and type III collagen showed codistribution in the same vesicular rER. (4) Vesicular rER showed negative or very faint labelling for fibronectin. These results may suggest regional differences in the function of rER. 相似文献
39.
Motoki Tagami Kazuo Yamagata Hideaki Fujino Akiyoshi Kubota Yasuo Nara Yukio Yamori 《Cell and tissue research》1992,268(2):225-232
Summary In this study bovine aortic endothelial cells were co-cultured with astrocytes from fetal Wistar Kyoto rats. Endothelial cells growing on type-I collagen, development. Although some cells appeared to be mature, horseradish peroxidase penetrated within 1 min of incubation through the intercellular junctions of these endothelial elements maintained on type-I collagen. In contrast, endothelial cells on type-IV collagen, co-cultured with astrocytes, were well developed; their intercellular junctions were well established, and plasmalemmal vesicles reduced in number. As a result, horseradish peroxidase was unable to penetrate through the endothelial cells grown on type-IV collagen and co-cultured with astrocytes because of the reduced extent of the junctional and vesicular transport. These findings reveal that (1) type-IV collagen is essential for the differentiation of endothelial cells, (2) endothelial cell-astrocyte interactions occur during co-culture, and (3) endothelial permeability depends on astrocyte-produced factors, in addition to type-IV collagen. 相似文献
40.
Systematic sequencing of the Escherichia coli genome: analysis of the 0-2.4 min region. 总被引:23,自引:7,他引:16
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
T Yura H Mori H Nagai T Nagata A Ishihama N Fujita K Isono K Mizobuchi A Nakata 《Nucleic acids research》1992,20(13):3305-3308
A contiguous 111,402-nucleotide sequence corresponding to the 0 to 2.4 min region of the E. coli chromosome was determined as a first step to complete structural analysis of the genome. The resulting sequence was used to predict open reading frames and to search for sequence similarity against the PIR protein database. A number of novel genes were found whose predicted protein sequences showed significant homology with known proteins from various organisms, including several clusters of genes similar to those involved in fatty acid metabolism in bacteria (e.g., betT, baiF) and higher organisms, iron transport (sfuA, B, C) in Serratia marcescens, and symbiotic nitrogen fixation or electron transport (fixA, B, C, X) in Azorhizobium caulinodans. In addition, several genes and IS elements that had been mapped but not sequenced (e.g., leuA, B, C, D) were identified. We estimate that about 90 genes are represented in this region of the chromosome with little spacer. 相似文献