全文获取类型
收费全文 | 29070篇 |
免费 | 2455篇 |
国内免费 | 21篇 |
出版年
2023年 | 80篇 |
2022年 | 178篇 |
2021年 | 469篇 |
2020年 | 273篇 |
2019年 | 348篇 |
2018年 | 430篇 |
2017年 | 368篇 |
2016年 | 607篇 |
2015年 | 1076篇 |
2014年 | 1291篇 |
2013年 | 1534篇 |
2012年 | 2021篇 |
2011年 | 2043篇 |
2010年 | 1329篇 |
2009年 | 1144篇 |
2008年 | 1786篇 |
2007年 | 1842篇 |
2006年 | 1691篇 |
2005年 | 1635篇 |
2004年 | 1661篇 |
2003年 | 1582篇 |
2002年 | 1478篇 |
2001年 | 336篇 |
2000年 | 260篇 |
1999年 | 358篇 |
1998年 | 396篇 |
1997年 | 296篇 |
1996年 | 252篇 |
1995年 | 242篇 |
1994年 | 252篇 |
1993年 | 257篇 |
1992年 | 244篇 |
1991年 | 245篇 |
1990年 | 201篇 |
1989年 | 186篇 |
1988年 | 196篇 |
1987年 | 182篇 |
1986年 | 180篇 |
1985年 | 208篇 |
1984年 | 201篇 |
1983年 | 211篇 |
1982年 | 227篇 |
1981年 | 201篇 |
1980年 | 175篇 |
1979年 | 142篇 |
1978年 | 143篇 |
1977年 | 115篇 |
1976年 | 105篇 |
1975年 | 85篇 |
1974年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
Timothy Ipoola Olabiyi Jonathan Jeremiah Atungwu Betty Izuogu John Akintola Stephen Abolusoro 《Archives Of Phytopathology And Plant Protection》2013,46(18):2253-2258
The effects of neem compost on root knot nematode, Meloidogyne incognita, pest of Lagos spinach, Celosia argentea, cv. TLV 8, was studied during 2010 and 2011 planting seasons on the field. The trial was conducted at the Teaching and Research Farm of Ladoke Akintola University of Technology, Ogbomoso, Nigeria. There were four treatments, replicated five times fitted into randomised complete block design. Neem compost was applied at 1.0, 1.5 and 2.0?tonnes/ha. Experimental plots, where no compost was applied served as the control. The result obtained shows that Lagos spinach treated with neem compost significantly (p?<?0.05) reduced the final soil nematode population and root infections (damage), with resultant improvement on crop growth and yield. The result of the chemical analysis of the neem compost revealed the presence of flavonoids, sterols, glycosides, alkaloids and saponins. 相似文献
973.
Mateusz Siedlinski Dustin Tingley Peter J. Lipman Michael H. Cho Augusto A. Litonjua David Sparrow Per Bakke Amund Gulsvik David A. Lomas Wayne Anderson Xiangyang Kong Stephen I. Rennard Terri H. Beaty John E. Hokanson James D. Crapo Christoph Lange Edwin K. Silverman 《Human genetics》2013,132(4):431-441
Cigarette smoking is the major environmental risk factor for chronic obstructive pulmonary disease (COPD). Genome-wide association studies have provided compelling associations for three loci with COPD. In this study, we aimed to estimate direct, i.e., independent from smoking, and indirect effects of those loci on COPD development using mediation analysis. We included a total of 3,424 COPD cases and 1,872 unaffected controls with data on two smoking-related phenotypes: lifetime average smoking intensity and cumulative exposure to tobacco smoke (pack years). Our analysis revealed that effects of two linked variants (rs1051730 and rs8034191) in the AGPHD1/CHRNA3 cluster on COPD development are significantly, yet not entirely, mediated by the smoking-related phenotypes. Approximately 30 % of the total effect of variants in the AGPHD1/CHRNA3 cluster on COPD development was mediated by pack years. Simultaneous analysis of modestly (r 2 = 0.21) linked markers in CHRNA3 and IREB2 revealed that an even larger (~42 %) proportion of the total effect of the CHRNA3 locus on COPD was mediated by pack years after adjustment for an IREB2 single nucleotide polymorphism. This study confirms the existence of direct effects of the AGPHD1/CHRNA3, IREB2, FAM13A and HHIP loci on COPD development. While the association of the AGPHD1/CHRNA3 locus with COPD is significantly mediated by smoking-related phenotypes, IREB2 appears to affect COPD independently of smoking. 相似文献
974.
Shivani Srivastava David Pelloso Hailin Feng Larry Voiles David Lewis Zdenka Haskova Margaret Whitacre Stephen Trulli Yi-Jiun Chen John Toso Zdenka L. Jonak Hua-Chen Chang Michael J. Robertson 《Cancer immunology, immunotherapy : CII》2013,62(6):1073-1082
The antitumor activity of monoclonal antibodies is mediated by effector cells, such as natural killer (NK) cells, that express Fc receptors for immunoglobulin. Efficacy of monoclonal antibodies, including the CD20 antibody rituximab, could be improved by agents that augment the function of NK cells. Interleukin (IL)-18 is an immunostimulatory cytokine that has antitumor activity in preclinical models. The effects of IL-18 on NK cell function mediated through Fcγ receptors were examined. Human NK cells stimulated with immobilized IgG in vitro secreted IFN-γ as expected; such IFN-γ production was partially inhibited by blocking CD16 with monoclonal antibodies. IL-18 augmented IFN-γ production by NK cells stimulated with immobilized IgG or CD16 antibodies. NK cell IFN-γ production in response to immobilized IgG and/or IL-18 was inhibited by chemical inhibitors of Syk and several other kinases involved in CD16 signaling pathways. IL-18 augmented antibody-dependent cellular cytotoxicity (ADCC) of human NK cells against rituximab-coated Raji cells in vitro. IL-18 and rituximab acted synergistically to promote regression of human lymphoma xenografts in SCID mice. Inasmuch as IL-18 costimulates IFN-γ production and ADCC of NK cells activated through Fc receptors in vitro and augments antitumor activity of rituximab in vivo, it is an attractive cytokine to combine with monoclonal antibodies for treatment of human cancer. 相似文献
975.
Joseph F. Boland Charles C. Chung David Roberson Jason Mitchell Xijun Zhang Kate M. Im Ji He Stephen J. Chanock Meredith Yeager Michael Dean 《Human genetics》2013,132(10):1153-1163
We assessed the performance of the new Life Technologies Proton sequencer by comparing whole-exome sequence data in a Centre d’Etude du Polymorphisme Humain trio (family 1463) to the Illumina HiSeq instrument. To simulate a typical user’s results, we utilized the standard capture, alignment and variant calling methods specific to each platform. We restricted data analysis to include the capture region common to both methods. The Proton produced high quality data at a comparable average depth and read length, and the Ion Reporter variant caller identified 96 % of single nucleotide polymorphisms (SNPs) detected by the HiSeq and GATK pipeline. However, only 40 % of small insertion and deletion variants (indels) were identified by both methods. Usage of the trio structure and segregation of platform-specific alleles supported this result. Further comparison of the trio data with Complete Genomics sequence data and Illumina SNP microarray genotypes documented high concordance and accurate SNP genotyping of both Proton and Illumina platforms. However, our study underscored the problem of accurate detection of indels for both the Proton and HiSeq platforms. 相似文献
976.
977.
978.
979.
980.
Amaia Artal-Martinez de Narvajas Timothy S. Gomez Jin-San Zhang Alexander O. Mann Yoshiyuki Taoda Jacquelyn A. Gorman Marta Herreros-Villanueva Thomas M. Gress Volker Ellenrieder Luis Bujanda Do-Hyung Kim Alan P. Kozikowski Alexander Koenig Daniel D. Billadeau 《Molecular and cellular biology》2013,33(20):3983-3993