全文获取类型
收费全文 | 6755篇 |
免费 | 603篇 |
国内免费 | 14篇 |
专业分类
7372篇 |
出版年
2024年 | 8篇 |
2023年 | 68篇 |
2022年 | 137篇 |
2021年 | 236篇 |
2020年 | 106篇 |
2019年 | 171篇 |
2018年 | 189篇 |
2017年 | 184篇 |
2016年 | 243篇 |
2015年 | 364篇 |
2014年 | 357篇 |
2013年 | 453篇 |
2012年 | 539篇 |
2011年 | 503篇 |
2010年 | 314篇 |
2009年 | 249篇 |
2008年 | 332篇 |
2007年 | 353篇 |
2006年 | 298篇 |
2005年 | 283篇 |
2004年 | 214篇 |
2003年 | 197篇 |
2002年 | 235篇 |
2001年 | 162篇 |
2000年 | 205篇 |
1999年 | 141篇 |
1998年 | 53篇 |
1997年 | 31篇 |
1996年 | 36篇 |
1995年 | 46篇 |
1994年 | 35篇 |
1993年 | 35篇 |
1992年 | 74篇 |
1991年 | 64篇 |
1990年 | 59篇 |
1989年 | 60篇 |
1988年 | 47篇 |
1987年 | 33篇 |
1986年 | 43篇 |
1985年 | 47篇 |
1984年 | 26篇 |
1983年 | 22篇 |
1982年 | 12篇 |
1981年 | 18篇 |
1980年 | 8篇 |
1979年 | 16篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有7372条查询结果,搜索用时 15 毫秒
991.
Huang X Nguyen AT Li Z Emelyanov A Parinov S Gong Z 《Birth defects research. Part C, Embryo today : reviews》2011,93(2):173-181
The zebrafish (Danio rerio) has been an experimental model in the developmental biology and toxicology since the 1950s. In recent years, with the aid of transgenic technology, it has also gained an increasing popularity to model human diseases, including various cancers. As a feasible vertebrate model for large-scale chemical screens, the zebrafish has also given us a new option for the search of potential anticancer drugs. It is hopeful that in the near future with automation and analytical tools, drug development processes will be significantly shortened for quick and effective identification of candidate drugs. 相似文献
992.
993.
Huy NT Hamada M Kikuchi M Lan NT Yasunami M Zamora J Hirayama K 《Parasitology international》2011,60(4):347-356
Several human genetic variants, HLA antigens and alleles are reportedly linked to post-schistosomal hepatic disorder (PSHD), but the results from these reports are highly inconclusive. In order to estimate overall associations between human genetic variants, HLA antigens, HLA alleles and PSHD, we systematically reviewed and performed a meta-analysis of relevant studies in both post-schistosomal hepatic disorder and post-schistosomal non-hepatic disorder patients. PubMed, Scopus, Google Scholar, The HuGE Published Literature database, Cochrane Library, and manual search of reference lists of articles published before July 2009 were used to retrieve relevant studies. Two reviewers independently selected articles and extracted data on study characteristics and data regarding the association between genetic variants, HLA antigens, HLA alleles and PSHD in the form of 2×2 tables. A meta-analysis using fixed-effects or random-effects models to pooled odds ratios (OR) with corresponding 95% confidence intervals were calculated only if more than one study had investigated particular variation. We found 17 articles that met our eligibility criteria. Schistosoma mansoni and Schistosoma japonicum were reported as the species causing PSHD. Since human genetic variants were only investigated in one study, these markers were not assessed by meta-analysis. Thus, only HLA-genes (a total of 66 HLA markers) were conducted in the meta-analysis. Our meta-analysis showed that human leucocyte antigens HLA-DQB1*0201 (OR=2.64, P=0.018), DQB1*0303 (OR=1.93, P=0.008), and DRB1*0901 (OR=2.14, P=0.002) alleles and HLA-A1 (OR=5.10, P=0.001), A2 (OR=2.17, P=0.005), B5 (OR=4.63, P=0.001), B8 (OR=2.99, P=0.02), and B12 (OR=5.49, P=0.005) serotypes enhanced susceptibility to PSHD, whereas HLA-DQA1*0501 (OR=0.29, P≤0.001) and DQB1*0301 (OR=0.58, P=0.007) were protective factors against the disease. We further suggested that the DRB1*0901-DQB1*0201, DRB1*0901-DQB1*0303 and A1-B8 haplotypes enhanced susceptibility to PSHD, whereas DQA1*0501-DQB1*0301 linkage decreased the risk of PSHD. The result improved our understanding of the association between the HLA loci and PSHD with regard to pathogenic or protective T-cells and provided novel evidence that HLA alleles may influence disease severity. 相似文献
994.
Nguyen H. Dung Zhi Qiang Ou Luana Caron Lian Zhang Dinh T. Cam Thanh Gilles A. de Wijs Rob A. de Groot K. H. Jürgen Buschow Ekkes Brück 《Liver Transplantation》2011,1(6):1215-1219
The efficient coupling between lattice degrees of freedom and spin degrees of freedom in magnetic materials can be used for refrigeration and energy conversion. This coupling is enhanced in materials exhibiting the giant magnetocaloric effect. First principle electronic structure calculations on hexagonal MnFe(P, Si) reveal a new form of magnetism: the coexistence of strong and weak magnetism in alternate atomic layers. The weak magnetism of Fe layers (disappearance of local magnetic moments at the Curie temperature) is responsible for a strong coupling with the crystal lattice while the strong magnetism in adjacent Mn‐layers ensures Curie temperatures high enough to enable operation at and above room temperature. Varying the composition on these magnetic sublattices gives a handle to tune the working temperature and to achieve a strong reduction of the undesired thermal hysteresis. In this way we design novel materials based on abundantly available elements with properties matched to the requirements of an efficient refrigeration or energy‐conversion cycle. 相似文献
995.
996.
So MT Leon TY Cheng G Tang CS Miao XP Cornes BK Diem NN Cui L Ngan ES Lui VC Wu XZ Wang B Wang H Yuan ZW Huang LM Li L Xia H Zhu D Liu J Nguyen TL Chan IH Chung PH Liu XL Zhang R Wong KK Sham PC Cherny SS Tam PK Garcia-Barcelo MM 《PloS one》2011,6(12):e28986
Rare (RVs) and common variants of the RET gene contribute to Hirschsprung disease (HSCR; congenital aganglionosis). While RET common variants are strongly associated with the commonest manifestation of the disease (males; short-segment aganglionosis; sporadic), rare coding sequence (CDS) variants are more frequently found in the lesser common and more severe forms of the disease (females; long/total colonic aganglionosis; familial).Here we present the screening for RVs in the RET CDS and intron/exon boundaries of 601 Chinese HSCR patients, the largest number of patients ever reported. We identified 61 different heterozygous RVs (50 novel) distributed among 100 patients (16.64%). Those include 14 silent, 29 missense, 5 nonsense, 4 frame-shifts, and one in-frame amino-acid deletion in the CDS, two splice-site deletions, 4 nucleotide substitutions and a 22-bp deletion in the intron/exon boundaries and 1 single-nucleotide substitution in the 5' untranslated region. Exonic variants were mainly clustered in RET the extracellular domain. RET RVs were more frequent among patients with the most severe phenotype (24% vs. 15% in short-HSCR). Phasing RVs with the RET HSCR-associated haplotype suggests that RVs do not underlie the undisputable association of RET common variants with HSCR. None of the variants were found in 250 Chinese controls. 相似文献
997.
Nguyen HP Hanson J Bethell D Nguyen TH Tran TH Ly VC Pham PL Dinh XS Dondorp A White N Tran TH Day N 《PloS one》2011,6(10):e25523
Background
Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults.Methods
Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation.Results
43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m2 (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: −0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (rs = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO2/FiO2 ratio). There was no correlation between the oxygen delivery (DO2) and base deficit at the 63 time-points where they were assessed simultaneously (rs = −0.09, p = 0.46).Conclusions
In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs. 相似文献998.
Background
Neuromuscular (NM) synaptogenesis is a tightly regulated process. We previously showed that in flies, Drosophila Nedd4 (dNedd4/dNedd4S) is required for proper NM synaptogenesis by promoting endocytosis of commissureless from the muscle surface, a pre-requisite step for muscle innervation. DNedd4 is an E3 ubiquitin ligase comprised of a C2-WW(x3)-Hect domain architecture, which includes several splice isoforms, the most prominent ones are dNedd4-short (dNedd4S) and dNedd4-long (dNedd4Lo).Methodology/Principal Findings
We show here that while dNedd4S is essential for NM synaptogenesis, the dNedd4Lo isoform inhibits this process and causes lethality. Our results reveal that unlike dNedd4S, dNedd4Lo cannot rescue the lethality of dNedd4 null (DNedd4T121FS) flies. Moreover, overexpression of UAS-dNedd4Lo specifically in wildtype muscles leads to NM synaptogenesis defects, impaired locomotion and larval lethality. These negative effects of dNedd4Lo are ameliorated by deletion of two regions (N-terminus and Middle region) unique to this isoform, and by inactivating the catalytic activity of dNedd4Lo, suggesting that these unique regions, as well as catalytic activity, are responsible for the inhibitory effects of dNedd4Lo on synaptogenesis. In accord with these findings, we demonstrate by sqRT-PCR an increase in dNedd4S expression relative to the expression of dNedd4Lo during embryonic stages when synaptogenesis takes place.Conclusion/Significance
Our studies demonstrate that splice isoforms of the same dNedd4 gene can lead to opposite effects on NM synaptogenesis. 相似文献999.
1000.
Lazaro E Tram LT Bellecave P Guidicelli GL Anies G Thu HH Debelleix MP Vray M Recordon-Pinson P Taupin JL Lien TT Fleury H 《PloS one》2011,6(10):e26244