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991.
Jung-Kyen Moon Jung-Won Park Woo Song Lee Young-Jin Kang Hyun-A Chung Mi-Seon Shin Yong-Jin Yoon Ki Hun Park 《Journal of heterocyclic chemistry》1999,36(3):793-798
This paper presents the synthesis of 2-amino-, 2-acetamido- and 2-benzamidothioxanthones and their 10,10-dioxides. 相似文献
992.
993.
The purpose of this paper is to generalize Yalçin's result [Trans. Amer. Math. Soc. 352 , 2689–2700 (2000)] from tori to solvmanifolds. As a result, we prove that if (?p)r acts freely on a solvmanifold M of dimension n, then r ≤ n (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
994.
Jong Taek Cho 《Monatshefte für Mathematik》2010,160(4):347-357
As a real hypersurface in a complex space, we prove two criterion inequalities for an odd-dimensional sphere in terms of the shape operator, the Reeb vector field and its associated 1-form. Also, we determine a real hypersurface in a complex space which admits a Ricci soliton with the Reeb vector field the potential vector field. 相似文献
995.
Saram Lee Segyeong Joo Sejin Park Soyoun Kim Hee Chan Kim Taek Dong Chung 《Electrophoresis》2010,31(10):1623-1629
In this study, in situ surface‐enhanced Raman scattering (SERS) decoding was demonstrated in microfluidic chips using novel thin micro gold shells modified with Raman tags. The micro gold shells were fabricated using electroless gold plating on PMMA beads with diameter of 15 μm. These shells were sophisticatedly optimized to produce the maximum SERS intensity, which minimized the exposure time for quick and safe decoding. The shell surfaces produced well‐defined SERS spectra even at an extremely short exposure time, 1 ms, for a single micro gold shell combined with Raman tags such as 2‐naphthalenethiol and benzenethiol. The consecutive SERS spectra from a variety of combinations of Raman tags were successfully acquired from the micro gold shells moving in 25 μm deep and 75 μm wide channels on a glass microfluidic chip. The proposed functionalized micro gold shells exhibited the potential of an on‐chip microfluidic SERS decoding strategy for micro suspension array. 相似文献
996.
Sung Joong Lee Semin Park Jin Young Choi Jae‐Han Shim Eun‐Ho Shin Jeong‐Heui Choi Soo Taek Kim A. M. Abd El‐Aty Jong Sung Jin Dong Won Bae Sung Chul Shin 《Biomedical chromatography : BMC》2009,23(7):719-731
It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean‐up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB‐C18 column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100γij (%). A high matrix effect (30%) was detected for the seven polar pesticides, namely thiamethoxam, clothianidin, acetamiprid, aldicarb, thiacloprid, pirimicarb and methabenzthiazuron. The limits of detection were in the range of 0.1–8.1 µg/kg, indicating a good sensitivity. Most of the recoveries ranged from 70 to 131% with RSDs ≤ 20%. The current method allowed rapid quantitation and identification of low pesticide levels in the cooked vegetable samples. Of the screened pesticide residues, only fluquinconazole and dimethomorph below the maximum residue levels established by the KFDA were detected in onion and cucumber samples. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
997.
Jaehyun Moon Yong-Hae Kim Choong-Heui Chung Su-Jae Lee Dong-Jin Park Yoon-Ho Song 《Applied Surface Science》2008,254(20):6422-6427
The growth of Si oxide by means of a cyclic radio-frequency (rf) plasma oxidation process has been explored in a low temperature range of 100-200 °C. The growth mechanism exhibits Cabrera-Mott (CM) oxidation, that is, the transport of mobile ionic species is assisted by an electric field. The low activation energy of 0.3 eV is attributed to the small size of O− and the assistance of the electric field. The oxide becomes off-stoichiometric as one approaches to the exterior surface of the oxide layer. 相似文献
998.
Soojin Park Wha‐Keun Ahn Sunyoung Lee Sang Yun Han Bum Ku Rhee Han Bin Oh 《Rapid communications in mass spectrometry : RCM》2009,23(23):3609-3620
Ultraviolet (UV) photodissociation (PD) experiments using 266 nm light were performed for a series of phosphopeptide cations in a Fourier transform mass spectrometer. The objective of the experiments was to determine whether 266 nm UV irradiation on the phosphopeptide cations would induce unique peptide backbone dissociation. In addition, the general behavior of the phosphate loss (?80 or ?98 Da) was monitored, particularly for those phosphopeptides with a phosphotyrosine residue that itself is a UV chromophore. For phosphopeptides with a UV chromophore, their photodissociation behavior was very similar to that of low‐energy sustained off‐resonance irradiation collisionally activated dissociation (SORI‐CAD), with a few exceptions. For example, b‐ and y‐type peptide backbone fragments were prevalent, and their dephosphorylation behavior was consistent with that of the SORI‐CAD results. For phosphoserine peptides, the loss of a phosphate group was always observed. On the other hand, for phosphotyrosine peptides, the phosphate loss was found to be dependent on the presence of a basic amino group in the sequence and the charge state of the precursor ions, in agreement with the CAD results in the literature. However, hydrogen atom loss or aromatic side chain loss, which is known to be the excited state specific fragmentation pathway, was rarely observed in our 266 nm UV PD experiments, in contrast to the previous UV PD literature (particularly at 220 nm). The mechanism for these observations is described in terms of dominant internal conversion followed by intramolecular vibrational energy redistribution (IVR). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
999.
1000.
A series of crosslinked polymer electrolyte membranes were prepared by blending cellulose and sulfosuccinic acid (SA) for
fuel cell applications. The crosslinking reaction of membranes occurred via the esterification between –OH of cellulose and
–COOH of SA, as confirmed by FT-IR spectroscopy. Both the ion exchange capacity and the proton conductivity increased in proportion
to the increase of SA concentrations due to the increasing portion of charged groups in the membrane. In contrast, the water
uptake linearly increased up to 25 wt.% of SA concentration, above which it decreased abruptly. The maximum behavior of water
uptake may be a result of competitive effect between the increasing number of ionic sites and the increasing degree of crosslinking
with the SA concentrations. Wide angle X-ray scattering also showed that the crystalline structures of cellulose disappeared
upon the introduction of SA. The mechanical properties of cellulose/SA membranes, i.e., tensile strength at break and Young’s
modulus, showed a maximum at 15 wt.% of SA, as revealed by universal testing machine. These membranes exhibited good thermal
stability up to 250 °C, as revealed by thermal gravimetric analysis. 相似文献