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91.
Robin Zuluaga Jean-Luc Putaux Adriana Restrepo Iñaki Mondragon Piedad Gañán 《Cellulose (London, England)》2007,14(6):585-592
Cellulose microfibrils have been prepared from banana rachis using a combination of chemical and mechanical treatments. The
morphology and structure of the samples were characterized using transmission electron microscopy, atomic force microscopy,
and X-ray diffraction. Fourier-transformed infrared spectroscopy (FTIR) was used to characterize the chemical modifications
of the samples after each treatment. Suspensions of bundled or individualized 5-nm-wide microfibrils were obtained after homogenization
(PH) whereas an organosolv (PO) treatment resulted in shorter aggregates of parallel cellulose microcrystallites. The sharper
rings in the X-ray diffraction pattern of the PO-treated sample suggest a higher crystallinity due to a more efficient removal
of hemicelluloses and dissolution of amorphous zones by the acid treatment. Both microfibrils and microcrystals prepared by
both methods can be used as reinforcing filler in nanocomposite materials. 相似文献
92.
Thyme (Thymus vulgaris) has been known, long time ago, for its aromatic properties. It contains essential oils and polymers such as cellulose (mixture of hemicellulose and cellulose) and lignin. The thyme, studied in this work, was gathered from the same place, in the period from November 1999 to October 2000. The chemical analysis (water, total ash, essential oils, extractive substances, cellulose, holocellulose and lignin) can be used roughly in the characterisation of the four periods that correspond to the four seasons of the year. The cellulose level was found to be more than lignin level in the wet periods (growth of the plant). The opposite was found in the dry periods. The total ash and essential oil levels were found to be high during the period of high pluviometry. The thermal decomposition of cellulose and holocellulose was found to fit well with the first-order kinetics. The activation energy, under air flow, was 185 and 196 kJ mol−1 for cellulose and holocellulose, respectively. The maximum decomposition rate and thermal analysis heating rate of lignin were found to have a direct linear relationship. 相似文献
93.
The effects of adding millimolar quantities of a series of compounds containing the carbonyl function on the conductances of solutions (0.2 mM) of tri-n-butylammonium picrate ino-dichlorobenzene solvent at 25°C have been measured. Values of the complex formation constants K
1
+
for 1:1 cation-ligand complexes are derived from these data. The corresponding values of –G
1
0
at 25°C are (in kcal-mole
–1
): 4-butyrolactone, 4.29; propylene carbonate, 3.87; ethylene carbonate, 3.59; cyclopentanone, 3.42; ethyl acetate, 2.84; and diethyl carbonate, 2.78. These results together with earlier results from this laboratory are discussed in terms of the effects of structure on cation-ligand affinity. 相似文献
94.
利用色相色谱/质谱联用技术,傅立叶红外及裂解-气相色谱/质谱联用技术,对印刷用上光油的关键成分进行了分析,共鉴定出7种挥发性组分,2种高分子聚合物。 相似文献
95.
96.
97.
Studies were carried out on saccharification of pretreated tapioca waste and water hyacinth under two different conditions:
using microbial enzymes (cellulase fromMyrothecium verrucaria, Coprinus comatus,Pleurotus florida, andCellulomonas sp.) and solid-state fermentation. The rate of saccharification was determined at different temperatures, pH, substrate concentration,
and incubation period. It was found that as the source of the enzyme varies, the optimal temperature and pH for the saccharification
varies. Among the two different treatments, enzymatic saccharification was found to be the most efficient. Among the various
cellulase sources tested, M.verrucaria cellulase was found to be the most efficient one followed byC. comatus, P. florida, and finallyCellulomonas sp. 相似文献
98.
R.?Mitchell C.?M.?CarrEmail author M.?Parfitt J.?C.?Vickerman C.?Jones 《Cellulose (London, England)》2005,12(6):629-639
The surface chemical composition of raw unscoured cotton was successfully investigated by the surface analytical techniques
X-ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The presence of non-cellulosic
material at the fibre surface was established and determined to be a complex mixture of fatty acids, alcohols, alkanes, esters
and glycerides. The effect of scouring and bleaching was to reduce the surface concentration of these materials but even after
aqueous processing some non-cellulosic material residue was still detected at the fibre surface. 相似文献
99.
100.