全文获取类型
收费全文 | 14962篇 |
免费 | 1354篇 |
国内免费 | 18篇 |
出版年
2022年 | 69篇 |
2021年 | 205篇 |
2020年 | 102篇 |
2019年 | 149篇 |
2018年 | 203篇 |
2017年 | 142篇 |
2016年 | 292篇 |
2015年 | 473篇 |
2014年 | 545篇 |
2013年 | 737篇 |
2012年 | 946篇 |
2011年 | 977篇 |
2010年 | 637篇 |
2009年 | 625篇 |
2008年 | 840篇 |
2007年 | 853篇 |
2006年 | 832篇 |
2005年 | 836篇 |
2004年 | 863篇 |
2003年 | 871篇 |
2002年 | 896篇 |
2001年 | 199篇 |
2000年 | 119篇 |
1999年 | 168篇 |
1998年 | 233篇 |
1997年 | 173篇 |
1996年 | 129篇 |
1995年 | 125篇 |
1994年 | 135篇 |
1993年 | 166篇 |
1992年 | 116篇 |
1991年 | 127篇 |
1990年 | 118篇 |
1989年 | 87篇 |
1988年 | 102篇 |
1987年 | 105篇 |
1986年 | 93篇 |
1985年 | 130篇 |
1984年 | 111篇 |
1983年 | 113篇 |
1982年 | 135篇 |
1981年 | 143篇 |
1980年 | 119篇 |
1979年 | 76篇 |
1978年 | 96篇 |
1977年 | 92篇 |
1976年 | 82篇 |
1975年 | 62篇 |
1974年 | 100篇 |
1973年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Screening for content--the evolution of high throughput 总被引:4,自引:0,他引:4
Dove A 《Nature biotechnology》2003,21(8):859-864
992.
993.
994.
We describe the occurrence of special kinds of hyphae that create anastomoses directly between conidia. They can be found both in the laboratory and on infected plants. They first appear within asexual fruiting bodies approximately 15 days after conidiation has begun leading to the appearance of chains of connected conidia. Coincident with this we demonstrate in Colletotrichum lindemuthianum nuclear dynamics, including fragmentation, with cytoplasmic flow and passage of nuclei and organelles between conidia through the anastomosis tubes. We propose that conidial anastomosis tubes play an important role in the life cycle of these fungi. 相似文献
995.
Thangavelu M James AB Bankier A Bryan GJ Dear PH Waugh R 《Plant biotechnology journal》2003,1(1):23-31
HAPPY mapping is an in vitro approach for defining the order and spacing of DNA markers directly on native genomic DNA. This cloning-free technique is based on analysing the segregation of markers amplified from high molecular weight genomic DNA which has been broken randomly and 'segregated' by limiting dilution into subhaploid samples. It is a uniquely versatile tool, allowing for the construction of genome maps with flexible ranges and resolutions. Moreover, it is applicable to plant genomes, for which many of the techniques pioneered in animal genomes are inapplicable or inappropriate. We report here its demonstration in a plant genome by reconstructing the physical map of a 1.9 Mbp region around the FCA locus of Arabidopsis thaliana. The resulting map, spanning around 10% of chromosome 4, is in excellent agreement with the DNA sequence and has a mean marker spacing of 16 kbp. We argue that HAPPY maps of any required resolution can be made immediately and with relatively little effort for most plant species and, furthermore, that such maps can greatly aid the construction of regional or genome-wide physical maps. 相似文献
996.
The morbidity caused by schistosomiasis has been controlled in China, Egypt and the Philippines mainly by the widespread use of the safe and efficacious drug praziquantel (PZQ), and by oxamniquin and PZQ in Brazil. To date, there is no evidence of development of clinically relevant resistance. Thanks to the commitment of national governments at the World Health Assembly in 2001, and the emergence of significant funding for control, it is predicted that there will soon be more widespread use of PZQ in sub-Saharan Africa, where morbidity due to schistosomiasis is most prevalent. There are currently no available alternative drugs to PZQ (with the possible exception of oxamniquin), although perhaps PZQ analogues could be developed. Artemether, used to control malaria, is effective against immature schistosomes, but is less effective against adult worms. The efficacy of myrrh, recently marketed as an antischistosomacide in Egypt, has not been independently confirmed. 相似文献
997.
Frederique Ponchel Carmel Toomes Kieran Bransfield Fong T Leong Susan H Douglas Sarah L Field Sandra M Bell Valerie Combaret Alain Puisieux Alan J Mighell Philip A Robinson Chris F Inglehearn John D Isaacs Alex F Markham 《BMC biotechnology》2003,3(1):1-13
Background
Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive.Results
We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells); the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy.Conclusion
Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting. 相似文献998.
A two-step method was developed to homogeneously insert carbonic anhydrase (CA, E.C. 4.2.1.1) into Michael-adduct-based coatings. CA was first covalently coupled to an N-vinylformamide-based water-soluble polymer. Unlike native CA, the resulting polymer/CA system could be dispersed within a film matrix. The enzyme-containing coating (ECC) hydrolyzes p-nitrophenyl propionate in buffered media at high rates retaining approximately 7% apparent activity. In comparison, other two-step techniques for the chemical coupling of CA to the coating surface were less efficient and led to coatings with significantly less activity. A three-step immobilization process coupling the enzyme to the surface of a partially hydrolyzed coating also raised retention of activity after coating synthesis. CA-ECC is stable under ambient conditions retaining 45% activity after 90 days of storage at room temperature. 相似文献
999.
Ng PS Pingle MR Balasundarum G Friedman A Zu X Bergstrom DE 《Nucleosides, nucleotides & nucleic acids》2003,22(5-8):1635-1637
The syntheses of endcaps for covalently linking the 3' and 5' hydroxyl groups of blunt end double-stranded DNA are described. Endcap diols were converted into DMTr protected phosphoramidites and incorporated between nucleotides 4 and 5 of a self-complementary octamer. The stabilizing effect of the endcaps on duplex DNA was determined by Tm experiments on the self-complementary octamer. 相似文献
1000.