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961.
Jun?Keun?ChangEmail author Yun?Seok?Heo Hyunwoo?Bang Keunchang?Cho Seok?Chung Chanil?Chung Dong?Chul?Han 《Biotechnology and Bioprocess Engineering》2003,8(4):233-239
For the quantitative analysis of an unknown sample a calibration curve should be obtained, as analytical instruments give
relative, rather than absolute measurements. Therefore, researchers should make standard samples with various known concentrations,
measure each standard and the unknown sample, and then determine the concentration of the unknown by comparing the measured
value to those of the standards. These procedures are tedious and time-consuming. Therefore, we developed a polymer based
microfluidic device from polydimethylsiloxane, which integrates serial dilution and capillary electrophoresis functions in
a single device. The integrated microchip can provide a one-step analytical tool, and thus replace the complex experimental
procedures. Two plastic syringes, one containing a buffer solution and the other a standard solution, were connected to two
inlet holes on a microchip, and pushed by a hydrodynamic force. The standard sample is serially diluted to various concentrations
through the microfluidic networks. The diluted samples are sequentially introduced through microchannels by electro-osmotic
force, and their laser-induced fluorescence signals measured by capillary electrophoresis. We demonstrate the integrated microchip
performance by measuring the fluorescence signals of fluorescein at various concentrations. The calibration curve obtained
from the electropherograms showed the expected linearity. 相似文献
962.
Dong?Won?Choi Woo?Gi?Lee Seong?Jin?Lim Byung?Jin?Kim Ho?Nam?ChangEmail author Seung?Teak?Chang 《Biotechnology and Bioprocess Engineering》2003,8(1):23-31
A mathematical model was formulated to simulate the long-term performance of an anaerobic bioreactor designed to digest Korean
food wastes. The system variables of various decomposition steps were built into the model, which predicts the temporal characters
of solid waste, and volatile fatty acid (VFA) in the reactor, and gas production in response to various input loadings and
temperatures. The predicted values of VFA and gas production were found to be in good agreement with experimental observations
in batch and repeated-input systems. Finally, long-term reactor performance was simulated with respect to the seasonal temperature
changes from 5°C in winter to 25°C in summer at different food waste input loadings. The simulation results provided us with
information concerning the success or failure of a process during long-term operation. 相似文献
963.
Kim SH Shin DH Choi IG Schulze-Gahmen U Chen S Kim R 《Journal of structural and functional genomics》2003,4(2-3):129-135
The dramatically increasing number of new protein sequences arising from genomics 4 proteomics requires the need for methods to rapidly and reliably infer the molecular and cellular functions of these proteins. One such approach, structural genomics, aims to delineate the total repertoire of protein folds in nature, thereby providing three-dimensional folding patterns for all proteins and to infer molecular functions of the proteins based on the combined information of structures and sequences. The goal of obtaining protein structures on a genomic scale has motivated the development of high throughput technologies and protocols for macromolecular structure determination that have begun to produce structures at a greater rate than previously possible. These new structures have revealed many unexpected functional inferences and evolutionary relationships that were hidden at the sequence level. Here, we present samples of structures determined at Berkeley Structural Genomics Center and collaborators laboratories to illustrate how structural information provides and complements sequence information to deduce the functional inferences of proteins with unknown molecular functions.Two of the major premises of structural genomics are to discover a complete repertoire of protein folds in nature and to find molecular functions of the proteins whose functions are not predicted from sequence comparison alone. To achieve these objectives on a genomic scale, new methods, protocols, and technologies need to be developed by multi-institutional collaborations worldwide. As part of this effort, the Protein Structure Initiative has been launched in the United States (PSI; www.nigms.nih.gov/funding/psi.html). Although infrastructure building and technology development are still the main focus of structural genomics programs [1–6], a considerable number of protein structures have already been produced, some of them coming directly out of semi-automated structure determination pipelines [6–10]. The Berkeley Structural Genomics Center (BSGC) has focused on the proteins of Mycoplasma or their homologues from other organisms as its structural genomics targets because of the minimal genome size of the Mycoplasmas as well as their relevance to human and animal pathogenicity (http://www.strgen.org). Here we present several protein examples encompassing a spectrum of functional inferences obtainable from their three-dimensional structures in five situations, where the inferences are new and testable, and are not predictable from protein sequence information alone. 相似文献
964.
Choi IG Shin DH Brandsen J Jancarik J Busso D Yokota H Kim R Kim SH 《Journal of structural and functional genomics》2003,4(1):31-34
Journal of Structural and Functional Genomics - 相似文献
965.
This review describes mechanisms of action of artemisinin-related antimalarials, emphasizing the site and target of activation, pathways of generating reactive species, and possible targets of free radicals with implications for antimalarial peroxide drug design. It also presents a useful link between the mode of action of artemisinin and that of chloroquine, and highlights redox cycles involved in the interaction between the drug and vital biomolecules. 相似文献
966.
967.
Hong IS Kim YK Choi WS Seo DW Yoon JW Han JW Lee HY Lee HW 《FEMS microbiology letters》2003,225(2):177-182
We previously reported the presence of nitric oxide synthase (NOS) in Staphylococcus aureus ATCC6538P whose activity was induced by methanol. In the present study, the methanol-induced NOS was purified 900-fold from S. aureus by means of Mono Q ion exchange column, 2',5'-ADP-agarose affinity column, and Superdex 200HR gel permeation column chromatography. The purified bacterial NOS showed two protein bands with 67 and 64 kDa molecular mass on SDS-PAGE. However, the molecular mass of the NOS was 135 kDa on Superdex 200HR gel permeation column chromatography, indicating that the native enzyme exists as a heterodimer. This bacterial NOS had K(m) value of 13.4x10(-6) M for L-arginine and V(max) of 35.3 nmol min(-1) mg(-1) protein. In addition, reduced nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide, flavin mononucleotide, tetrahydrobiopterin, calmodulin and Ca(2+) were required as cofactors in the conversion of L-arginine to L-citrulline, and NOS inhibitors selectively inhibited the activity of the purified NOS. 相似文献
968.
Jun Y Yi L Yong T Jianben L Xiong C Qin Z Jiaxin D Songsheng Q Ziniu Y 《Prikladnaia biokhimiia i mikrobiologiia》2003,39(6):656-660
By using an LKB-2277 Bioactivity Monitor, ampoule mode, the heat output of Bacillus thuringiensis growth metabolism has been determined at 28 degrees C and effect of Cu2+ on B. thuringiensis growth was studied. Copper has been regarded as an essential trace element for life. Its deficiency may be the cause of diseases. Cu2+ of different concentration have different effects on B. thuringiensis growth metabolism, Cu2+ of low concentration (0-30 micrograms/ml) can promote the growth of B. thuringiensis, and Cu2+ of high concentration (40-120 micrograms/ml) is able to inhibit its growth and B. thuringiensis can't grow at all when the concentration of Cu2+ is up to 130 micrograms/ml. 相似文献
969.
970.
Structures of the alpha L I domain and its complex with ICAM-1 reveal a shape-shifting pathway for integrin regulation 总被引:7,自引:0,他引:7
Shimaoka M Xiao T Liu JH Yang Y Dong Y Jun CD McCormack A Zhang R Joachimiak A Takagi J Wang JH Springer TA 《Cell》2003,112(1):99-111
The structure of the I domain of integrin alpha L beta 2 bound to the Ig superfamily ligand ICAM-1 reveals the open ligand binding conformation and the first example of an integrin-IgSF interface. The I domain Mg2+ directly coordinates Glu-34 of ICAM-1, and a dramatic swing of I domain residue Glu-241 enables a critical salt bridge. Liganded and unliganded structures for both high- and intermediate-affinity mutant I domains reveal that ligand binding can induce conformational change in the alpha L I domain and that allosteric signals can convert the closed conformation to intermediate or open conformations without ligand binding. Pulling down on the C-terminal alpha 7 helix with introduced disulfide bonds ratchets the beta 6-alpha 7 loop into three different positions in the closed, intermediate, and open conformations, with a progressive increase in affinity. 相似文献