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41.
The unc-52 gene of Claenorhabditis elegans encodes a homologue of the basement membrane heparan sulfate proteoglycan perlecan. Viable alleles reduce the abundance of UNC-52 in late larval stages and increase the frequency of distal tip cell (DTC) migration defects caused by mutations disrupting the UNC-6/netrin guidance system. These unc-52 alleles do not cause circumferential DTC migration defects in an otherwise wild-type genetic background. The effects of unc-52 mutations on DTC migrations are distinct from effects on myofilament organization and can be partially suppressed by mutations in several genes encoding growth factor-like molecules, including EGL-17/FGF, UNC-129/TGF-beta, DBL-1/TGF-beta, and EGL-20/WNT. We propose that UNC-52 serves dual roles in C. elegans larval development in the maintenance of muscle structure and the regulation of growth factor-like signaling pathways. 相似文献
42.
43.
Shigemitsu T Ozaki S Saito Y Kuroda M Morita S Satoh S Masumura T 《Plant cell reports》2012,31(3):539-549
Rice seeds are potentially useful hosts for the production of pharmaceutical proteins. However, low yields of recombinant
proteins have been observed in many cases because recombinant proteins compete with endogenous storage proteins. Therefore,
we attempt to suppress endogenous seed storage proteins by RNA interference (RNAi) to develop rice seeds as a more efficient
protein expression system. In this study, human growth hormone (hGH) was expressed in transgenic rice seeds using an endosperm-specific
promoter from a 10 kDa rice prolamin gene. In addition, an RNAi cassette for reduction of endogenous storage protein expressions
was inserted into the hGH expression construct. Using this system, the expression levels of 13 kDa prolamin and glutelin were
effectively suppressed and hGH polypeptides accumulated to 470 μg/g dry weight at the maximum level in transgenic rice seeds.
These results suggest that the suppression of endogenous protein gene expression by RNAi could be of great utility for increasing
transgene products. 相似文献
44.
Masahiro Tsujino Masakazu Hori Takehiro Okuda Masahiro Nakaoka Tomoko Yamamoto Takashi Noda 《Population Ecology》2010,52(1):171-180
It is well known that the similarity in species composition between two communities decays with the geographic distance that
separates them. It is thus likely that the similarity in the dynamics of two communities also decays with distance, because
the distance–decay relationship is fundamental in nature. However, the distance–decay relationships of community dynamics
have not yet been revealed. We used transition matrix models to evaluate distance–decay relationships of seasonal community
dynamics (from spring to summer) in rocky intertidal sessile assemblages along the Pacific coast of Japan between 31°N and
43°N. We evaluated the distance–decay relationships of whole-community dynamics and of three dynamics-related components—recruitment,
disturbance, and species interaction (competition and facilitation)—for communities separated by distances ranging from several
meters to thousands of kilometers. The similarity of the recruitment dynamics among communities declined rapidly with distance
within the fine spatial scale, but only moderately within larger scales. The similarity of the disturbance dynamics was independent
of distance, and the similarity of species interaction declined slightly with increasing distance. The similarity of whole-community
dynamics declined rapidly with distance at a fine spatial scale and moderately at larger scales. The fact that the distance–decay
relationship of whole-community dynamics was similar to that of recruitment may suggest that recruitment processes are the
most important determinant of spatial variability of community dynamics at our study sites during the study period. 相似文献
45.
Regiane Marinho da Silva Gui Mi Ko Rinaldo Florêncio Silva Ludmila Cabreira Vieira Rafael Vicente de Paula Júlio Takehiro Marumo Amanda Ikegami Maria Helena Bellini 《Biological trace element research》2018,182(2):303-308
Acute kidney injury (AKI) is an important health problem and can be caused by number of factors. The use of aminoglycosides, such as gentamicin, is one of these factors. Recently, an effort has been made to find biomarkers to guide treatment protocols. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the contents of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn in serum and urine of the healthy, AKI, and spontaneous recovery (SR) groups of animals. The animal model of AKI and SR was validated by measuring serum and urinary urea and creatinine. The quantitative determination of the elements showed a decrease in serum levels of Ca, and Fe in the AKI group (P<0.01 vs. healthy), with a return to normal levels in the SR group, without a significant difference between the healthy and SR groups. In the urine samples, there was a decrease in P and Na levels in the AKI group (P<0.001 and P<0.01 vs. healthy), but Ca levels were increased in this group compared with the healthy and SR groups (P<0.01). These findings indicate that mineral elements might be useful as biomarkers for AKI. 相似文献
46.
Mashiko S Ishihara A Iwaasa H Moriya R Kitazawa H Mitobe Y Ito J Gomori A Matsushita H Takahashi T MacNeil DJ Van der Ploeg LH Fukami T Kanatani A 《Obesity (Silver Spring, Md.)》2008,16(7):1510-1515
Objective: To further address the function of the Y5 receptor in energy homeostasis, we investigated the effects of a novel spironolactone Y5 antagonist in diet-induced obese (DIO) mice. Methods and Procedures: Male C57BL/6 or Npy5r−/− mice were adapted to high-fat (HF) diet for 6–10 months and were submitted to three experimental treatments. First, the Y5 antagonist at a dose of 10 or 30 mg/kg was administered for 1 month to DIO C57BL/6 or Npy5r−/− mice. Second, the Y5 antagonist at 30 mg/kg was administered for 1.5 months to DIO C57BL/6 mice, and insulin sensitivity was evaluated using an insulin tolerance test. After a recovery period, nuclear magnetic resonance measurement was performed to evaluate body composition. Third, DIO mice were treated with the Y5 antagonist alone, or in combination with 10% food restriction, or with another anorectic agent, sibutramine at 10 mg/kg, for 1.5 months. Plasma glucose, insulin, and leptin levels, and adipose tissue weights were quantified. Results: The spironolactone Y5 antagonist significantly reduced body weight in C57BL DIO mice, but not in Npy5r−/− DIO mice. The Y5 antagonist produced a fat-selective loss of body weight, and ameliorated obesity-associated insulin resistance in DIO mice. In addition, the Y5 antagonist combined with either food restriction or sibutramine tended to produce greater body weight loss, as compared with single treatment. Discussion: These findings demonstrate that the Y5 receptor is an important mediator of energy homeostasis in rodents. 相似文献
47.
Takabe K Mase N Matsumura H Hasegawa T Iida Y Kuribayashi H Adachi K Yoda H Ao M 《Bioorganic & medicinal chemistry letters》2002,12(17):2295-2297
Lipase-catalyzed kinetic resolution of the N,N-dialkyl-3-benzyloxymethyl-4-hydroxybutanamide 10a,b afforded the acetate 11a,b with (R) configuration, whereas the N-monoalkyl-3-benzyloxymethyl-4-hydroxybutanamide 10c-e gave the acetate 11c-e with (S) configuration. The butanamide 10 smoothly cyclized to give chiral 4-benzyloxymethyldihydrofuran-2-one 9 without racemization, which was effectively transformed into highly stereocontrolled virginiae butanolide C (VB C). 相似文献
48.
49.
Gao SY Li CY Shimokawa T Terashita T Matsuda S Yaoita E Kobayashi N 《Cell and tissue research》2007,328(2):391-400
Intercellular adhesions between renal glomerular epithelial cells (also called podocytes) are necessary for the proper function
of the glomerular filtration barrier. Although our knowledge of the molecular composition of podocyte cell-cell contact sites
has greatly progressed, the underlying molecular mechanism regulating the formation of these cell-cell contacts remains largely
unknown. We have used forskolin, an activator of adenylyl cyclase that elevates the level of intracellular cAMP, to investigate
the effect of cAMP and three Rho-family small GTPases (RhoA, Cdc42, and Rac1) on the regulation of cell-cell contact formation
in a murine podocyte cell line. Transmission electron microscopy and the immunostaining of cell adhesion molecules and actin-associated
proteins have revealed a structural change at the site of cell-cell contact following forskolin treatment. The activity of
the Rho-family small GTPases before and after forskolin treatment has been evaluated with a glutathione-S-transferase pull-down
assay. Forskolin reinforces the integrity of cell-cell contacts, resulting in the closure of an intercellular adhesion zipper,
accompanied by a redistribution of cell adhesion molecules and actin-associated proteins in a continuous linear pattern at
cell-cell contacts. The Rho-family small GTPases Rac1 and Cdc42 are activated during closure of the adhesion zipper, whereas
RhoA is suppressed. Thus, cAMP promotes the assembly of cell-cell contacts between podocytes via a mechanism that probably
involves Rho-family small GTPases.
This study was supported in part by a grant-in-aid for scientific research from the Japanese Ministry for Education, Culture,
Sports, Science, and Technology (to N. K., no. 14570015). S-Y.G. is a recipient of a grant awarded by the Japanese government
to graduate students from foreign countries. 相似文献
50.
Narimoto T Sakurai K Okamoto A Chatani E Hoshino M Hasegawa K Naiki H Goto Y 《FEBS letters》2004,576(3):313-319
Although the stability of globular proteins has been studied extensively, that of amyloid fibrils is scarcely characterized. Beta2-microglobulin (beta2-m) is a major component of the amyloid fibrils observed in patients with dialysis-related amyloidosis. We studied the effects of guanidine hydrochloride on the amyloid fibrils of beta2-m, revealing a cooperative unfolding transition similar to that of the native state. The stability of amyloid fibrils increased on the addition of ammonium sulfate, consistent with a role of hydrophobic interactions. The results indicate that the analysis of unfolding transition is useful to obtain insight into the structural stability of amyloid fibrils. 相似文献