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991.
Fibroblast growth factors 总被引:1,自引:0,他引:1
Fibroblast growth factors (FGFs) make up a large family of polypeptide growth factors that are found in organisms ranging from nematodes to humans. In vertebrates, the 22 members of the FGF family range in molecular mass from 17 to 34 kDa and share 13-71% amino acid identity. Between vertebrate species, FGFs are highly conserved in both gene structure and amino-acid sequence. FGFs have a high affinity for heparan sulfate proteoglycans and require heparan sulfate to activate one of four cell-surface FGF receptors. During embryonic development, FGFs have diverse roles in regulating cell proliferation, migration and differentiation. In the adult organism, FGFs are homeostatic factors and function in tissue repair and response to injury. When inappropriately expressed, some FGFs can contribute to the pathogenesis of cancer. A subset of the FGF family, expressed in adult tissue, is important for neuronal signal transduction in the central and peripheral nervous systems. 相似文献
992.
Kajiwara H Morimoto S Fukuda N Ohtsuki I Kurihara S 《Biochemical and biophysical research communications》2000,272(1):104-110
We examined the effect of troponin I (TnI) phosphorylation by cAMP-dependent protein kinase (PKA) on the length-dependent tension activation in skinned rat cardiac trabeculae. Increasing sarcomere length shifted the pCa (-log[Ca2+])-tension relation to the left. Treatment with PKA decreased the Ca2+ sensitivity of the myofilament and also decreased the length-dependent shift of the pCa-tension relation. Replacement of endogenous TnI with phosphorylated TnI directly demonstrated that TnI phosphorylation is responsible for the decreased length-dependence. When MgATP concentration was lowered in the absence of Ca2+, tension was elicited through rigorous cross-bridge-induced thin filament activation. Increasing sarcomere length shifted the pMgATP (-log[MgATP])-tension relation to the right, and either TnI phosphorylation or partial extraction of troponin C (TnC) abolished this length-dependent shift. We conclude that TnI phosphorylation by PKA attenuates the length-dependence of tension activation in cardiac muscle by decreasing the cross-bridge-dependent thin filament activation through a reduction of the interaction between TnI and TnC. 相似文献
993.
Nobuyuki Kutsukake 《Primates; journal of primatology》2000,41(3):321-335
In many cercopithecine primates, females form linear dominance hierarchies based on kinship. It is known that female rank
follows the rules of matrilineal rank inheritance (MIR): (1) maternal rank inheritance, (2) maternal dominance, and (3) youngest
ascendancy among sisters. Although, several determining such variation remain largely unknown. In this paper, I investigate
the dominance relation-ships of 69 adult (>6 yr old) female Japanese macaques (Macaca fuscata fuscata) in a free-ranging provisioned troop living in Shiga-Heights (Nagano Prefecture, Japan) and report new evidence of intra-group
variation. Dominance relationships among high-ranking females followed MRI within kin units, those among low-ranking females
did not. Maternal rank inheritance and youngest ascendancy operated between mother/daughter dyads and sister dyads of high-rank,
but not in the dyads of low-rank. The dominance ranks of females from low-ranking kin units were dispersed and less predictable.
These findings suggest that MRI varies with absolute dominance rank, and are discussed in relation to other asymmetries between
high-and low-rank 相似文献
994.
T. Matsuda K. Hatano T. Harioka F. Taura H. Tanaka N. Tateishi S. Shan S. Morimoto Y. Shoyama 《Plant cell reports》2000,19(4):390-394
Strong activity of β-glucuronidase first appeared in the epidermal and glandular hair cells of leaf primordia regenerated
from callus of Scutellaria baicalensis Georgi. Leaf primordia matured rapidly in culture to form shoots within 1 month in which both the mesophyll cells and the
glandular hairs were deeply stained. Leaves predominantly accumulated β-glucuronidase in both glandular hair cells and mesophyll
cells. β-Glucronidase activity in leaves was higher in the summer and decreased in the winter. The stem section collected
in the summer had a different β-glucuronidase distribution pattern from that of the root in that in the former strong activity
appeared in the periderm cells and collenchyma cells which was decreasingly dispersed into the phloem layer cells. In the
winter, β-glucronidase activity decreased compared to that in summer. It can be argued that the distribution of β-glucuronidase
in this plant is closely linked with the defense against pathogens: it is a starting key enzyme which may act together with
the flavonoids, which play an important role as a proton donor for the detoxification metabolism of H2O2.
Received: 1 December 1998 / Revision received: 10 March 1999 / Accepted: 14 June 1999 相似文献
995.
Satoshi Ohmori Teruaki Hayashi Masami Kawase Setsuo Saito Yasunori Morimoto 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2000,740(2):253-263
The extraordinarily strong analgesic dihydroetorphine (DHE) was registered as one of the most strictly controlled narcotic drugs by the United Nations in 1999. However, an effective detection method for DHE in biological samples has not yet been established. We developed a quantitative method for assay of DHE in rat plasma and brain by liquid chromatography–tandem mass spectrometry equipped with an ionspray interface. A 0.5-ml volume of plasma and brain homogenate spiked with buprenorphine (internal standard) was purified by the solid-phase extraction column Bond Elute Certify. DHE produced numerous weak fragment ions by collision induced dissociation. Therefore, collision energy was utilized to decompose the interferences, and the protonated molecular ion was used for both precursor and product ion monitoring. As a result of the method validation, the dynamic concentration range was determined as 0.05–10 ng/ml. DHE in these samples was stable for 2 months at −4°C and for 24 h at ambient temperatures. Using the present method, DHE was detected in rat plasma and brain tissue after intravenous injection (0.5 μg/kg). 相似文献
996.
During meiosis, the rapid movement of telomeres along the nuclear envelope (NE) facilitates pairing/synapsis of homologous chromosomes. In mammals, the mechanical properties of chromosome movement and the cytoskeletal structures responsible for it remain poorly understood. Here, applying an in vivo electroporation (EP) technique in live mouse testis, we achieved the quick visualization of telomere, chromosome axis and microtubule organizing center (MTOC) movements. For the first time, we defined prophase sub-stages of live spermatocytes morphologically according to GFP-TRF1 and GFP-SCP3 signals. We show that rapid telomere movement and subsequent nuclear rotation persist from leptotene/zygotene to pachytene, and then decline in diplotene stage concomitant with the liberation of SUN1 from telomeres. Further, during bouquet stage, telomeres are constrained near the MTOC, resulting in the transient suppression of telomere mobility and nuclear rotation. MTs are responsible for these movements by forming cable-like structures on the NE, and, probably, by facilitating the rail-tacking movements of telomeres on the MT cables. In contrast, actin regulates the oscillatory changes in nuclear shape. Our data provide the mechanical scheme for meiotic chromosome movement throughout prophase I in mammals. 相似文献
997.
Suguru Miyagawa Toshifumi Mihashi Hiroyuki Kanda Yoko Hirohara Takao Endo Takeshi Morimoto Tomomitsu Miyoshi Takashi Fujikado 《PloS one》2014,9(8)
To investigate the changes in the wavefront aberrations and pupillary shape in response to electrical stimulation of the branches of the ciliary nerves in cats. Seven eyes of seven cats were studied under general anesthesia. Trains of monophasic pulses (current, 0.1 to 1.0 mA; duration, 0.5 ms/phase; frequency, 5 to 40 Hz) were applied to the lateral or medial branch of the short ciliary nerve near the posterior pole of the eye. A pair of electrodes was hooked onto one or both branch of the short ciliary nerve. The electrodes were placed about 5 mm from the scleral surface. The wavefront aberrations were recorded continuously for 2 seconds before, 8 seconds during, and for 20 seconds after the electrical stimulation. The pupillary images were simultaneously recorded during the stimulation period. Both the wavefront aberrations and the pupillary images were obtained 10 times/sec with a custom-built wavefront aberrometer. The maximum accommodative amplitude was 1.19 diopters (D) produced by electrical stimulation of the short ciliary nerves. The latency of the accommodative changes was very short, and the accommodative level gradually increased up to 4 seconds and reached a plateau. When only one branch of the ciliary nerve was stimulated, the pupil dilated asymmetrically, and the oblique astigmatism and one of the asymmetrical wavefront terms was also altered. Our results showed that the wavefront aberrations and pupillary dilations can be measured simultaneously and serially with a compact wavefront aberrometer. The asymmetric pupil dilation and asymmetric changes of the wavefront aberrations suggest that each branch of the ciliary nerve innervates specific segments of the ciliary muscle and dilator muscle of the pupil. 相似文献
998.
999.
1000.
Nobuyuki Mase Azusa Inoue Masaki Nishio Kunihiko Takabe 《Bioorganic & medicinal chemistry letters》2009,19(14):3955-3958
Optically active lactones are important synthons in perfume and aroma manufacturing. Therefore, developments of efficient asymmetric syntheses are desired. Organocatalytic asymmetric α-hydroxymethylations of cyclopentanone with aqueous formaldehyde have been developed, to furnish the corresponding α-(hydroxymethyl)cyclopentanone with high enantioselectivity. Further chemical transformation of α-(hydroxymethyl)cyclopentanone gave the key intermediate for jasmine lactone, which is widely found in fruits and flowers. 相似文献