全文获取类型
收费全文 | 2293篇 |
免费 | 104篇 |
国内免费 | 1篇 |
出版年
2023年 | 20篇 |
2022年 | 17篇 |
2021年 | 65篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 68篇 |
2017年 | 54篇 |
2016年 | 84篇 |
2015年 | 132篇 |
2014年 | 163篇 |
2013年 | 221篇 |
2012年 | 208篇 |
2011年 | 220篇 |
2010年 | 115篇 |
2009年 | 105篇 |
2008年 | 122篇 |
2007年 | 136篇 |
2006年 | 114篇 |
2005年 | 88篇 |
2004年 | 75篇 |
2003年 | 77篇 |
2002年 | 66篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有2398条查询结果,搜索用时 15 毫秒
11.
Narendra S. Goel Carlos F. Doggenweiler Richard L. Thompson 《Bulletin of mathematical biology》1986,48(2):167-187
A model based upon minimization of surface energy is proposed as an explanation for compaction and internalization of cells
during mammalian embryo development. The model is used to simulate and graphically display these phenomena on a computer. 相似文献
12.
The effect of foliar sprays of the growth regulator 2-(3,4 dichlorophenoxy)-triethylamine (DCPTA) on net photosynthesis (Pn) by intact bean plants depended upon concentration and the stage of development of the leaves. A single foliar spray of 2.0 mM DCPTA reduced Pn when applied to young expanding leaves but had little effect on fully expanded leaves. Lower DCPTA concentrations (0.2 to 0.8 mM) had no effect on Pn, unless applied more than once which resulted in reduced Pn. The DCPTA-induced inhibition of Pn was associated with chlorosis and aberrations in chloroplast ultrastructure. DCPTA did not affect stomatal resistance. When applied to detached leaf disks in the dark, DCPTA retarded the normal loss of chlorophyll suggesting that DCPTA may have anti-seneseent properties.Abbreviations DCPTA
2-(3,4 dichlorophenoxy)-triethylamine
- Pn
net photosynthesis
- Is
stomatal diffusive resistance 相似文献
13.
The witches' broom disease has been recently observed on poplars in Paris and its suburbs. The incidence of the disease appeared to be considerably high along main roads. The electron microscopic examination of 350 nm thick sieve tube sections revealed the presence of wall-less mycoplasmalike organisms (MLOs) in diseased samples of Populus alba var. nivea Wesm. They could not be found in their healthy counterparts. 相似文献
14.
Mycopathologia - A new entomogenous species ofPhoma, P. aspidioticola, has been described on a scale insect (Aspidiotus destructor Sign.) from India on the basis of morphological characters and... 相似文献
15.
Purification and characterization of the inositol 1,4,5-trisphosphate receptor protein from rat vas deferens 总被引:5,自引:0,他引:5 下载免费PDF全文
Robert J. Mourey Ajay Verma Surachai Supattapone Solomon H. Snyder 《The Biochemical journal》1990,272(2):383-389
Among rat peripheral tissues examined, Ins(1,4,5)P(3) receptor binding is highest in the vas deferens, with levels about 25% of those of the cerebellum. We have purified the InsP(3) receptor binding protein from rat vas deferens membranes 600-fold. The purified protein displays a single 260 kDa band on SDS/PAGE, and the native protein has an apparent molecular mass of 1000 kDa, the same as in cerebellum. The inositol phosphate specificity, pH-dependence and influence of various reagents are the same for purified vas deferens and cerebellar receptors. Whereas particulate InsP(3) binding in cerebellum is potently inhibited by Ca(2+), particulate and purified vas deferens receptor binding of InsP(3) is not influenced by Ca(2+). Vas deferens appears to lack calmedin activity, but the InsP(3) receptor is sensitive to Ca(2+) inhibition conferred by brain calmedin. The vas deferens may prove to be a valuable tissue for characterizing functional aspects of InsP(3) receptors. 相似文献
16.
Alterations in cell membrane structure and expression of a membrane-associated protein after adaptation to osmotic stress 总被引:3,自引:0,他引:3
17.
Renu Tuteja Narendra Tuteja Franco Lilliu Bruno Bembi Renzo Galanello Antonio Cao Francisco E. Baralle 《Human genetics》1994,94(3):314-315
We report a novel mutation in exon 9 of the glucocerebrosidase gene of a patient with Gaucher disease and of Sardinian origin. 相似文献
18.
Candidiasis was experimentally produced in young Japanese quail by oral administration ofCandida albicans cells. Lesions were confined to upper digestive tract with most characteristic changes occurring on the mucosa of crop. No lesions were observed in other tissues of the body. The initial changes in the crop were characterized by thickening and yellowish-white necrotic plaques on the mucosa. From 10th day onwards, there was marked thickening and corrugations of the crop mucosa giving it a typical turkish towel appearance. Varying degree of mucosal swelling was also observed in the oesophagus and proventriculus. Two of the infected birds also revealed yellowish-white necrotic plaques on the tongue at 7th and 10th day post-infection. The prominent microscopic lesions in the crop and tongue consisted of hyperkeratosis and parakeratosis with congestion of the subepithelial tissues. Varying degree of parakeratosis and epithelial hyperplasia coupled with subepithelial oedema and hypertrophy of glands was observed in the oesophagus. The proventriculus and small intestine revealed congestion, oedema, mild to marked goblet cell hyperplasia and focal epithelial sloughing. Fungal elements could be demonstrated in the sections of tongue upto 10 days while in crop upto 14 days post-infection. Reisolation of the fungus was consistently achieved from the crop of infected birds throughout the duration of the experiment. 相似文献
19.
Pornanong Aramwit Qiuran Jiang Supritha Muppuri Narendra Reddy 《Biotechnology and bioengineering》2023,120(10):2827-2839
Transgenic modification of Bombyx mori silkworms is a benign approach for the production of silk fibers with extraordinary properties and also to generate therapeutic proteins and other biomolecules for various applications. Silk fibers with fluorescence lasting more than a year, natural protein fibers with strength and toughness exceeding that of spider silk, proteins and therapeutic biomolecules with exceptional properties have been developed using transgenic technology. The transgenic modifications have been done primarily by modifying the silk sericin and fibroin genes and also the silk producing glands. Although the genetic modifications were typically performed using the sericin 1 and other genes, newer techniques such as CRISPR/Cas9 have enabled successful modifications of both the fibroin H-chain and L-chain. Such modifications have led to the production of therapeutic proteins and other biomolecules in reasonable quantities at affordable costs for tissue engineering and other medical applications. Transgenically modified silkworms also have distinct and long-lasting fluorescence useful for bioimaging applications. This review presents an overview of the transgenic techniques for modifications of B. mori silkworms and the properties obtained due to such modifications with particular focus on production of growth factors, fluorescent proteins, and high performance protein fibers. 相似文献
20.
Narendra Tuteja Ning Wu Huang Doris Skopac Renu Tuteja Sara Hrvatic Jianwen Zhang Sandor Pongor Grard Joseph Christian Faucher Franois Amalric Arturo Falaschi 《Gene》1995,160(2):143-148
The cDNA encoding human DNA helicase IV (HDH IV), a 100-kDa protein which unwinds DNA in the 5′ to 3′ direction with respect to the bound strand, was cloned and sequenced. It was found to be identical to the human cDNA encoding nucleolin, a ubiquitous eukaryotic protein essential for pre-ribosome assembly. HDH IV/nucleolin can unwind RNA-RNA duplexes, as well as DNA-DNA and DNA-RNA duplexes. Phosphorylation of HDH IV/nucleolin by cdc2 kinase and casein kinase II enhanced its unwinding activity in an additive way. The Gly-rich C-terminal domain possesses a limited ATP-dependent duplex-unwinding activity which contributes to the helicase activity of HDH IV/nucleolin. 相似文献