全文获取类型
收费全文 | 2220篇 |
免费 | 112篇 |
国内免费 | 4篇 |
出版年
2023年 | 17篇 |
2022年 | 57篇 |
2021年 | 98篇 |
2020年 | 58篇 |
2019年 | 79篇 |
2018年 | 79篇 |
2017年 | 83篇 |
2016年 | 119篇 |
2015年 | 154篇 |
2014年 | 156篇 |
2013年 | 213篇 |
2012年 | 203篇 |
2011年 | 183篇 |
2010年 | 104篇 |
2009年 | 86篇 |
2008年 | 67篇 |
2007年 | 78篇 |
2006年 | 69篇 |
2005年 | 66篇 |
2004年 | 55篇 |
2003年 | 23篇 |
2002年 | 40篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 18篇 |
1984年 | 6篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1970年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有2336条查询结果,搜索用时 15 毫秒
21.
The HML and HMR loci carry unexpressed copies of MATa and MATα information, and a replica of that information is transposed to MAT during mating-type interchange in Saccharomyces yeasts. A negative control mechanism keeps silent the information located at the HML and HMR loci. We mapped these loci by constructing strains in which these loci are expressed. In these strains, the mating type of the segregants is dependent upon the allele at HML and HMR. This novel approach is independent of their switching function. HML is located on the left arm of chromosome III distal to his4 by about 26.8 centimorgans (cM). HMR maps on the right arm of the same chromosome distal to thr4 by about 39.8 cM and proximal to MAL2 by about 1.0 cM. The results allow the exact placement of these loci and are in accord with the observations made by Harashima and Oshima (1976). 相似文献
22.
Amar Chatterjee 《Prostaglandins & other lipid mediators》1976,12(4):525-534
A comparative assessment of the efficacy of prolactin or HCG in reversing the luteolytic property of a single dose (2.0 mg/kg) of PGF2a was conducted in pregnant (day 10) rats. It was found that prolactin maintained pregnancy in 90% of the test animals. HCG though found to maintain pregnancy in 70% of the PGF2a-treated pregnants, the fetal survival rate was, however, recorded to be 62% against the control value of 98%. Conversely, prolactin replacement maintained the fetal survival rate as high as 93.4%. Moreover, the growth of the fetuses, placentae and corpus luteum in the pregnants having prolactin in conjunction with PGF2a was also found to be greater compared to the animals which h ad a combined regimen of PGF2a and HCG, but identical to controls. On the other hand, similar combined regimen when applied to hysterectomized pregnant rats, it was observed that though the vaginal diestrus was maintained by the prolactin or HCG in the presence of PGF2a, the prolactin regimen was found to be superb compared to HCG in the maintenance of luteal weight and functional activity. It was concluded that the antifertility effect of PGF2a in the rat is primarily the consequence of luteolysis and prolactin seems to be a much more appropriate hormonal replacement compared to HCG, a long-acting LH, in antagonizing the luteolytic property of PGF2a. 相似文献
23.
Genome-wide expression profiling has revolutionized biomedical research; vast amounts of expression data from numerous studies of many diseases are now available. Making the best use of this resource in order to better understand disease processes and treatment remains an open challenge. In particular, disease biomarkers detected in case–control studies suffer from low reliability and are only weakly reproducible. Here, we present a systematic integrative analysis methodology to overcome these shortcomings. We assembled and manually curated more than 14 000 expression profiles spanning 48 diseases and 18 expression platforms. We show that when studying a particular disease, judicious utilization of profiles from other diseases and information on disease hierarchy improves classification quality, avoids overoptimistic evaluation of that quality, and enhances disease-specific biomarker discovery. This approach yielded specific biomarkers for 24 of the analyzed diseases. We demonstrate how to combine these biomarkers with large-scale interaction, mutation and drug target data, forming a highly valuable disease summary that suggests novel directions in disease understanding and drug repurposing. Our analysis also estimates the number of samples required to reach a desired level of biomarker stability. This methodology can greatly improve the exploitation of the mountain of expression profiles for better disease analysis. 相似文献
24.
Mashitoh Abd Rahman Faiqah Ramli Hamed Karimian Firouzeh Dehghan Noraziah Nordin Hapipah Mohd Ali Syam Mohan Najihah Mohd Hashim 《PloS one》2016,11(3)
Artonin E is a prenylated flavonoid isolated from the stem bark of Artocarpus elasticus Reinw.(Moraceae). This study aimed to investigate the apoptotic mechanisms induced by artonin E in a metastatic human ovarian cancer cell line SKOV-3 in vitro. MTT assay, clonogenic assay, acridine orange and propidium iodide double staining, cell cycle and annexin V analyses were performed to explore the mode of artonin E-induced cell death at different time points. DNA laddering, activation of caspases-3, -8, and -9, multi-parametric cytotoxicity-3analysis by high-content screening, measurement of reactive oxygen species generation, and Western blot were employed to study the pathways involved in the apoptosis. MTT results showed that artonin E inhibited the growth of SKOV-3 cells, with IC50 values of 6.5±0.5μg/mL after 72 h treatment, and showed less toxicity toward a normal human ovarian cell lineT1074, with IC50 value of 32.5±0.5μg/mL. Results showed that artonin E induced apoptosis and cell cycle arrest at the S phase. This compound also promoted the activation of caspases-3, -8, and -9. Further investigation into the depletion of mitochondrial membrane potential and release of cytochrome c revealed that artonin E treatment induced apoptosis via regulation of the expression of pro-survival and pro-apoptotic Bcl-2 family members. The expression levels of survivin and HSP70 proteins were also down regulated in SKOV-3 cells treated with artonin E. We propose that artonin E induced an antiproliferative effect that led to S phase cell cycle arrest and apoptosis through dysregulation of mitochondrial pathways, particularly the pro- and anti-apoptosis signaling pathways. 相似文献
25.
Amirah Hurzaid Tin-Yam Chan Siti Azizah Mohd Nor Zainal Abidin Muchlisin Wei-Jen Chen 《Zoologica scripta》2020,49(5):596-613
The decapod family Penaeidae comprises most of the economically important marine shrimp species. Its members are widespread throughout the world, with its highest species diversity centred in the Indo-West Pacific region. Despite this importance, their taxonomy, classification and phylogeny are not yet settled due in part to incongruence among hypotheses proposed from molecular versus morphological studies. In this study, using a thorough taxonomic sampling of especially the South-East Asian species, we aim to (a) utilize a reconstructed phylogeny to test the monophyly of the Penaeidae and its currently recognized genera and (b) explore its species diversity in South-East Asian waters. To infer the phylogeny, a combined gene data set (including 109 ingroup and six outgroup taxa) of mitochondrial genes, COI and 16S rRNA, and two nuclear genes, NaK and PEPCK, was utilized. To explore its diversity, another data set that included 371 COI gene sequences (231 newly generated and 140 retrieved from public sources) was compiled and subsequently analysed with two different tools (ABGD and bPTP) for species delimitation. Other than supporting the non-monophyly of the Penaeidae with the Sicyoniidae nested within the penaeid tribe Trachypenaeini, the genera Penaeus, Mierspenaeopsis and Parapenaeopsis were also revealed to be polyphyletic. Our species delimitation analysis inferred that 94 putative species actually existed within the 71 morphospecies reviewed, indicating an underestimated biodiversity in this family and the potential presence of new species within the following morphospecies: Kishinouyepenaeopsis cornuta, K. incisa, Mierspenaeopsis sculptilis, M hardwicki, Parapenaeopsis coromandelica and Penaeus monodon. 相似文献
26.
Parmar Heena Hati Subrota Panchal Gauravkumar Sakure Amar A. 《International journal of peptide research and therapeutics》2020,26(2):997-1011
International Journal of Peptide Research and Therapeutics - In the study, five different Lactobacillus cultures i.e. L. rhamnosus (NK2) (KR080695), L. casei (NK9) (KR732325), L. fermentum (M5)... 相似文献
27.
28.
29.
30.
Russian Journal of Bioorganic Chemistry - Pyridazines hold considerable interest relative to pharmacologically active molecules. The pyridazine compounds are exhibited different types of... 相似文献