全文获取类型
收费全文 | 30688篇 |
免费 | 68篇 |
国内免费 | 107篇 |
专业分类
系统科学 | 117篇 |
丛书文集 | 419篇 |
教育与普及 | 86篇 |
理论与方法论 | 115篇 |
现状及发展 | 14540篇 |
研究方法 | 1102篇 |
综合类 | 14171篇 |
自然研究 | 313篇 |
出版年
2013年 | 148篇 |
2012年 | 337篇 |
2011年 | 631篇 |
2008年 | 428篇 |
2007年 | 468篇 |
2006年 | 483篇 |
2005年 | 491篇 |
2004年 | 607篇 |
2003年 | 493篇 |
2002年 | 478篇 |
2001年 | 802篇 |
2000年 | 819篇 |
1999年 | 553篇 |
1994年 | 366篇 |
1992年 | 493篇 |
1991年 | 401篇 |
1990年 | 459篇 |
1989年 | 427篇 |
1988年 | 415篇 |
1987年 | 463篇 |
1986年 | 512篇 |
1985年 | 627篇 |
1984年 | 420篇 |
1983年 | 434篇 |
1982年 | 376篇 |
1981年 | 391篇 |
1980年 | 413篇 |
1979年 | 983篇 |
1978年 | 820篇 |
1977年 | 759篇 |
1976年 | 597篇 |
1975年 | 717篇 |
1974年 | 953篇 |
1973年 | 804篇 |
1972年 | 837篇 |
1971年 | 1047篇 |
1970年 | 1232篇 |
1969年 | 992篇 |
1968年 | 1005篇 |
1967年 | 927篇 |
1966年 | 786篇 |
1965年 | 613篇 |
1964年 | 229篇 |
1959年 | 340篇 |
1958年 | 600篇 |
1957年 | 454篇 |
1956年 | 371篇 |
1955年 | 362篇 |
1954年 | 366篇 |
1948年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
731.
Analysis of the mouse transcriptome based on functional annotation of 60,770 full-length cDNAs 总被引:6,自引:0,他引:6
Okazaki Y Furuno M Kasukawa T Adachi J Bono H Kondo S Nikaido I Osato N Saito R Suzuki H Yamanaka I Kiyosawa H Yagi K Tomaru Y Hasegawa Y Nogami A Schönbach C Gojobori T Baldarelli R Hill DP Bult C Hume DA Quackenbush J Schriml LM Kanapin A Matsuda H Batalov S Beisel KW Blake JA Bradt D Brusic V Chothia C Corbani LE Cousins S Dalla E Dragani TA Fletcher CF Forrest A Frazer KS Gaasterland T Gariboldi M Gissi C Godzik A Gough J Grimmond S Gustincich S Hirokawa N Jackson IJ Jarvis ED Kanai A 《Nature》2002,420(6915):563-573
732.
733.
734.
735.
736.
Porous inorganic solids can be synthesized in complex forms, and here we describe a simple method to create an ultralight, macroporous, crystalline vanadium oxide foam by bubbling oxygen gas produced in situ through a viscous vanadium oxide gel. This foaming process could be extended to other metal oxides. 相似文献
737.
MENG Jinhong ZHANG Hui David G. Evans DUAN Xue 《科学通报(英文版)》2005,50(22):2575-2581
A novel organic-inorganic composite, sorbic acid intercalated zinc aluminum layered double hydroxides (SA-ZnAl-LDHs) has been successfully assembled by a simple direct coprecipitation method. A holistic approach including normal XRD, FT-IR, and UV-Vis measurements and simultaneous TG/DTA/MS and in situ HT-XRD techniques was employed to explore the supramolecular intercalation structure and the thermal decomposition properties of as-syntheslzed SA-ZnAl-LDHs material. 相似文献
738.
通过旅游民族志研究对当代旅游人类学所面临的一些问题进行探讨,亦即不仅在旅游人类学范围内考察有关民族志问题,而且将这些问题置于人类学的当代实践之中,包括:长期和短期的民族志研究、民族志田野作业的传统、民族志的时空策略、旅游民族志中的特殊问题等。 相似文献
739.
Microbial starch-binding domains (SBD) and granule-bound starch synthase I (GBSSI) are proteins which are accumulated in potato starch granules. The efficiency of SBD and GBSSI for targeting active luciferase reporter proteins to granules during starch biosynthesis was compared. GBSSI or SBD sequences were fused to the N- or C-terminus of the luciferase (LUC) gene, via an artificial Pro-Thr encoding linker sequence. The genes were introduced into an amylose-free (amf) potato mutant. It appeared that SBD was superior to GBSSI as a targeting sequence, mainly because the luciferase retained higher activity in the SBD-containing fusion proteins than in the GBSSI-containing ones. 相似文献
740.
Mutations in genes encoding melanosomal proteins cause pigmentary glaucoma in DBA/2J mice. 总被引:11,自引:0,他引:11
Michael G Anderson Richard S Smith Norman L Hawes Adriana Zabaleta Bo Chang Janey L Wiggs Simon W M John 《Nature genetics》2002,30(1):81-85
Pigmentary glaucoma is a significant cause of human blindness. Abnormally liberated iris pigment and cell debris enter the ocular drainage structures, leading to increased intraocular pressure (IOP) and glaucoma. DBA/2J (D2) mice develop a form of pigmentary glaucoma involving iris pigment dispersion (IPD) and iris stromal atrophy (ISA). Using high-resolution mapping techniques, sequencing and functional genetic tests, we show that IPD and ISA result from mutations in related genes encoding melanosomal proteins. IPD is caused by a premature stop codon mutation in the Gpnmb (GpnmbR150X) gene, as proved by the occurrence of IPD only in D2 mice that are homozygous with respect to GpnmbR150X; otherwise, similar D2 mice that are not homozygous for GpnmbR150X do not develop IPD. ISA is caused by the recessive Tyrp1b mutant allele and rescued by the transgenic introduction of wildtype Tyrp1. We hypothesize that IPD and ISA alter melanosomes, allowing toxic intermediates of pigment production to leak from melanosomes, causing iris disease and subsequent pigmentary glaucoma. This is supported by the rescue of IPD and ISA in D2 eyes with substantially decreased pigment production. These data indicate that pigment production and mutant melanosomal protein genes may contribute to human pigmentary glaucoma. The fact that hypopigmentation profoundly alleviates the D2 disease indicates that therapeutic strategies designed to decrease pigment production may be beneficial in human pigmentary glaucoma. 相似文献