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941.
Jason A. Able Carl Rathus Ian D. Godwin 《In vitro cellular & developmental biology. Plant》2001,37(3):341-348
Summary This report outlines the development of optimized particle inflow gun (PIG) parameters for producing transgenic sorghum (Sorghum bicolor (L.) Moench). Both transient and stable expression were examined when determining these parameters. The uidA reporter gene (GUS) encoding β-glucuronidase was used in transient experiments and the green fluorescent protein (GFP) used
to monitor stable expression. Initially, optimization was conducted using leaf segments, as the generation of sorghum callus
in sufficiently large quantities is time-consuming. Following leaf optimization, experiments were conducted using callus,
identifying a high similarity between the two tissue types (r
s=0.83). High levels of GUS expression were observed in both leaf and callus material when most distant from the DNA expulsion
point, and using a pressure greater than 1800 kPa. A higher level of expression was also observed when the aperture of the
helium inlet valve was constricted. Using the optimized conditions (pressure of 2200 kPa, distance to target tissue of 15
cm from the expulsion point, and the aperture of the helium inlet valve at one full turn), three promoters (Ubiquitin, Actinl and CaMV 35S) were evaluated over a 72-h period using GUS as the reporter gene. A significantly higher number of GUS foci were counted
with the Ubiquitin construct over this period, compared to the Actinl and CaMV 35S constructs. Stable callus sectors (on 2 mg 1−1 bialaphos) with GFP expression were visualized for as long as 6 wk post-bombardment. Using this optimized protocol, several
plants were regenerated after having been bombarded with the pAHC20 construct (containing the bar gene), with molecular evidence confirming integration. 相似文献
942.
Effects of medium composition on the morphology and function of rat hepatocytes cultured as spheroids and monolayers 总被引:4,自引:0,他引:4
Geraldine A. Hamilton Carl Westmoreland Elisabeth George 《In vitro cellular & developmental biology. Animal》2001,37(10):656-667
Primary hepatocytes cultured as monolayers or as spheroids were studied to compare the effects of four different culture media (Williams' E, Chee's, Sigma Hepatocyte, and HepatoZYME medium). Rat hepatocytes were cultured as conventional monolayers for 3 d or as spheroids for 2 wk. For spheroid formation a method was emplOyed that combined the use of a nonadherent substratum with rotation of cultures. Hepatocyte integrity and morphology were assessed by light and electron microscopy and by reduced glutathione content. Hepatocyte function was measured by albumin secretion and 7-ethoxycoumarin metabolism. Chee's medium was found to be optimal for maintenance of hepatocyte viability and function in monolayers, but it failed to support spheroid formation. For spheroid formation and for the maintenance of spheroid morphology and function, Sigma HM was found to be optimal. These results demonstrate that the medium requirements of hepatocytes differ markedly depending on the culture model employed. Spheroid culture allowed better preservation of morphology and function of hepatocytes compared with conventional monolayer culture. Hepatocytes in spheroids formed bile canaliculi. and expressed an actin distribution resembling that found in hepatocytes in vivo. Albumin secretion was maintained at the same level as that found during the first d in primary culture, and 7-ethoxycoumarin metabolism was maintained over 2 wk in culture at approximately 30% of the levels found in freshly isolated hepatocytes. The improved morphology and function of hepatocyte cultures as spheroids may provide a more appropriate in vitro model for certain applications where the maintenance of liver-specific functions in long-term culture is crucial. 相似文献
943.
Carl J. Carrano Megan Jordan Hartmut Drechsel Dietmar G. Schmid Günther Winkelmann 《Biometals》2001,14(2):119-125
We report here on a new class of siderophores isolated from Rhodococcus erythropolis IGTS8, the first structurally characterized from any species of Rhodococcus and for which we suggest the name heterobactins. These siderophores consist of a tripeptide of sequence (N-OH)-L-Orn-Gly-D-Orn-(delta-N-dihydroyxbenzoate). The alpha amino group of the D-Orn is derivatized either as a 2-hydroxybenzoxazolate in heterobactin A or remains free in heterobactin B. The structures were determined by a combination of amino acid analysis, mass spectrometry and NMR methods. The two new compounds are true siderophores in that they relieve iron limited growth in the producing strain. The heterobactins are also transported by other non-producing bacteria. Growth promotion tests using various transport mutants revealed that in E. coli heterobactin A is only recognized by the catecholate receptor Cir while heterobactin B is taken up in both E.coli and A. flavescens JG9 via a hydroxamate transport system. 相似文献
944.
945.
Goedele Paternot Johanna Devroe Sophie Debrock Thomas M D'Hooghe Carl Spiessens 《Reproductive biology and endocrinology : RB&E》2009,7(1):105-6
Background
The aim of this study was to determine the intra- and inter-observer variability in the evaluation of embryo quality. Multilevel images of embryos on day 1, day 2 and day 3, were analysed using different morphological parameters. 相似文献946.
947.
948.
Agmenellum quadruplicatum strain PR-6 and Oscillatoria sp. strain JCM grown photoautotrophically in the presence of aniline metabolized the aromatic amine to formanilide, acetanilide and p-aminophenol. The metabolites were isolated by either thin-layer, gas-liquid or high pressure liquid chromatography and identified by comparison of their chromatographic, ultraviolet absorbance and mass spectral properties with those of authentic compounds. The toxicity of aniline derivatives towards Agmenellum quadruplicatum strain PR-6 indicated that the cyanobacterium was extremely sensitive to o-, m- and p-aminophenols, and phenylhydroxylamine.Abbreviations TLC
thin layer chromatography
- HPLC
high pressure liquid chromatography
- GC/MS
gas chromatography/mass spectrometry
- m/e
mass to charge ratio 相似文献
949.
950.