全文获取类型
收费全文 | 816篇 |
免费 | 29篇 |
专业分类
845篇 |
出版年
2024年 | 5篇 |
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 30篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 27篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 31篇 |
2014年 | 39篇 |
2013年 | 51篇 |
2012年 | 45篇 |
2011年 | 36篇 |
2010年 | 28篇 |
2009年 | 19篇 |
2008年 | 49篇 |
2007年 | 44篇 |
2006年 | 44篇 |
2005年 | 46篇 |
2004年 | 46篇 |
2003年 | 34篇 |
2002年 | 50篇 |
2001年 | 17篇 |
2000年 | 11篇 |
1999年 | 20篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有845条查询结果,搜索用时 15 毫秒
1.
Makoto Sakurai Susumu Nakakoji Hisaya Manabe Shin-ichi Dewa Akihiko Shinomiya Tomoki Sunobe 《Ichthyological Research》2009,56(1):82-86
Bi-directional sex change in the deep-water gobiid fish Trimma yanagitai was examined. The gonads of all individuals consisted of ovarian and testicular elements, and an accessory gonadal structure.
In no gonads were both testicular and ovarian parts simultaneously active. Bi-directional sex changes occurred during the
rearing experiments in aquaria under conditions of which there was co-existence of two males or plural females. The sex of
individuals could be determined by their relative body size or social dominance: the largest individuals acting as male and
the remainder as female. 相似文献
2.
Sakiyama Tomoki Morimoto Junko Matsubayashi Jun Furukawa Yasuto Kondo Mami Tsuruga Hifumi Mano Tsutomu Nakamura Futoshi 《Landscape and Ecological Engineering》2021,17(3):351-362
Landscape and Ecological Engineering - Investigating factors underlying human-wildlife conflicts in agricultural landscapes is important for both preventing crop damage and wildlife conservation.... 相似文献
3.
Kosugi A Koizumi Y Yanagida F Udaka S 《Bioscience, biotechnology, and biochemistry》2001,65(3):728-731
Using a mutant defective in cysteine uptake, which is resistant to a toxic analog of cysteine, allylglycine, we searched for a gene that complements the defect in cysteine uptake in a yeast genomic library and found a DNA fragment causing the recovery of cysteine uptake and sensitivity to allylglycine. The gene in the fragment was identical to MUP1, the high affinity methionine permease gene. We conclude that Mup1 is a major permease in cysteine uptake. 相似文献
4.
Mizushima T Hirao T Yoshida Y Lee SJ Chiba T Iwai K Yamaguchi Y Kato K Tsukihara T Tanaka K 《Nature structural & molecular biology》2004,11(4):365-370
SCF(Fbs1) is a ubiquitin ligase that functions in the endoplasmic reticulum (ER)-associated degradation pathway. Fbs1/Fbx2, a member of the F-box proteins, recognizes high-mannose oligosaccharides. Efficient binding to an N-glycan requires di-N-acetylchitobiose (chitobiose). Here we report the crystal structures of the sugar-binding domain (SBD) of Fbs1 alone and in complex with chitobiose. The SBD is composed of a ten-stranded antiparallel beta-sandwich. The structure of the SBD-chitobiose complex includes hydrogen bonds between Fbs1 and chitobiose and insertion of the methyl group of chitobiose into a small hydrophobic pocket of Fbs1. Moreover, NMR spectroscopy has demonstrated that the amino acid residues adjoining the chitobiose-binding site interact with the outer branches of the carbohydrate moiety. Considering that the innermost chitobiose moieties in N-glycans are usually involved in intramolecular interactions with the polypeptide moieties, we propose that Fbs1 interacts with the chitobiose in unfolded N-glycoprotein, pointing the protein moiety toward E2 for ubiquitination. 相似文献
5.
6.
Yamaguchi S Tanaka Y Banks S Kosugi S Sasho T Takahashi K Takakura Y 《Journal of biomechanics》2012,45(12):2103-2108
Relatively high rates of loosening and implant failure have been reported after total ankle arthroplasty. Abnormal kinematics and incongruency of the articular surface may cause increased contact pressure and rotational torque applied to the implant, leading to loosening and implant failure. We measured in vivo kinematics of two-component total ankle arthroplasty (TNK ankle), and assessed congruency of the articular surface during the stance phase of gait. Eighteen ankles of 15 patients with a mean age of 75±6 years (mean±standard deviation) and follow-up of 44±38 months were enrolled. Lateral fluoroscopic images were taken during the stance phase of gait. 3D-2D model-image registration was performed using the fluoroscopic image and the implant models, and three-dimensional kinematics of the implant and incongruency of the articular surface were determined. The mean ranges of motion were 11.1±4.6°, 0.8±0.4°, and 2.6±1.5° for dorsi-/plantarflexion, inversion/eversion, and internal/external rotation, respectively. At least one type of incongruency of the articular surface occurred in eight of 18 ankles, including anterior hinging in one ankle, medial or lateral lift off in four ankles, and excessive axial rotation in five ankles. Among the four ankles in which lift off occurred during gait, only one ankle showed lift off in the static weightbearing radiograph. Our observations will provide useful data against which kinematics of other implant designs, such as three-component total ankle arthroplasty, can be compared. Our results also showed that evaluation of lift off in the standard weightbearing radiograph may not predict its occurrence during gait. 相似文献
7.
Murata H Babasaki K Saegusa T Takemoto K Yamada A Ohta A 《Applied and environmental microbiology》2008,74(7):2023-2031
The ectomycorrhizal basidiomycete Tricholoma matsutake produces commercially valuable fruit bodies, matsutake, in forests. Here we report a PCR system targeting retroelement integration sites to differentiate among individual Asian isolates of T. matsutake based on their geographical origins, such as Japan, the area of South Korea through North Korea, the northeastern provinces of China, and the area of the southwestern provinces of China through Bhutan. The overall misjudgment rate of the analytical system was approximately 5% based on 95 samples of T. matsutake examined including those from cultures and from commodities. We also provide evidence that T. matsutake isolates grown throughout the Far East, including the northeastern provinces of China, are closely related to each other while distinct from those in the area of the southwestern provinces of China through Bhutan. The method allows us to trace back geographical origins of Asian matsutake, thus contributing to food safety, appropriate tariffs, and proper price setting. 相似文献
8.
Jin-Suk Han Yoshitsugu Kosugi Hiroyasu Ishida Kazuhiko Ishikawa 《European journal of biochemistry》2002,269(3):969-976
A gene having high sequence homology (45-49%) with the glycerol-1-phosphate dehydrogenase gene from Methanobacterium thermoautotrophicum was cloned from the aerobic hyperthermophilic archaeon Aeropyrum pernix K1 (JCM 9820). This gene expressed in Escherichia coli with the pET vector system consists of 1113 nucleotides with an ATG initiation codon and a TAG termination codon. The molecular mass of the purified enzyme was estimated to be 38 kDa by SDS/PAGE and 72.4 kDa by gel column chromatography, indicating presence as a dimer. The optimum reaction temperature of this enzyme was observed to be 94-96 degrees C at near neutral pH. This enzyme was subjected to two-substrate kinetic analysis. The enzyme showed substrate specificity for NAD(P)H-dependent dihydroxyacetone phosphate reduction and NAD(+)-dependent glycerol-1-phosphate (Gro1P) oxidation. NADP(+)-dependent Gro1P oxidation was not observed with this enzyme. For the production of Gro1P in A. pernix cells, NADPH is the preferred coenzyme rather than NADH. Gro1P acted as a noncompetitive inhibitor against dihydroxyacetone phosphate and NAD(P)H. However, NAD(P)(+) acted as a competitive inhibitor against NAD(P)H and as a noncompetitive inhibitor against dihydroxyacetone phosphate. This kinetic data indicates that the catalytic reaction by glycerol- 1-phosphate dehydrogenase from A. pernix follows a ordered bi-bi mechanism. 相似文献
9.
Tomoki Matsuda Makoto Fujikawa Mitsuru Haruki Xiao-Feng Tang Satoshi Ezaki Tadayuki Imanaka Masaaki Morikawa Shigenori Kanaya 《Extremophiles : life under extreme conditions》2001,5(3):177-182
Interactions of TBP-interacting protein (TIP26), TBP, and TFB from a hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 with TATA-DNA were examined by electrophoretic mobility shift assay. Tk-TFB formed a ternary complex with Tk-TBP and TATA-DNA. Tk-TIP26 did not inhibit the formation of this ternary complex, but interacted with it to form a TIP26/TFB/TBP/DNA quaternary complex. This interaction is rather weak, and a large excess of Tk-TIP26 over Tk-TBP is required to fully convert the TFB/TBP/DNA ternary complex to the quaternary complex. However, determination of the concentration of Tk-TIP26 and Tk-TBP in KOD1 cells by Western blotting analysis indicated that the concentration of Tk-TIP26 is approximately ten times that of Tk-TBP, suggesting that the quaternary complex might also form in vivo. 相似文献
10.