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21.
Summary The influence of food quantity and quality on growth and survival of Onychiurus armatus (Tullb.) in metal polluted environments has been investigated in laboratory experiments. The Collembola was reared on five species of fungi isolated from a metal polluted soil close to a brass mill in SE Sweden.Survival of O. armatus was improved when fungal biomass was continuously added in a polluted mor (1,300 ppm Zn and 200 ppm Cu), and when specimens were fed metal polluted fungi for 1, 3 and 7 days a week, only those that were starved had increased mortality. Allometric growth, on the other hand, was significantly reduced when Collembola was given surplus of metal polluted fungi, whereas growth losses caused by metals were offset by protein rich food. Hence, sufficient food quantities alone could overcome mortality losses but not growth retardation in a metal polluted environment.Feeding preference of O. armatus was not determined by the protein content of the fungi although this was beneficial for growth. Metals changed the relative palatability of fungal species, but one of the metal tolerant species, Paecilomyces farinosus, which was also protein rich, remained reasonably attractive for O. armatus also when it was metal polluted. The mechanisms by which growth and survival of O. armatus were promoted by a combination of protein and Zn/Cu rich fungi seemed to be crucial in understanding the fate of a population of this species in a metal polluted soil. 相似文献
22.
Maris G. N. Hartmanis Henrik Åhlman Sten Gatenbeck 《Applied microbiology and biotechnology》1986,23(5):369-371
Summary
Clostridium acetobutylicum ATCC 824 was submitted to repeated subculturing at 24-hour intervals for 218 days. The organism retained its ability to form solvents, although the fermentation slowly became increasingly acidogenic during the first 200 days. Except for the initial spore inoculum, the cultures were not subjected to heat shocking between the serial transfers. When the inoculum volume was doubled from 3.3% to 6.7% after 200 days of subculturing, the product formation pattern quickly shifted back from acids to primarily butanol. Acetone production also resumed after being undetectable for more than 50 days. The relative formation of acetate and ethanol remained nearly constant throughout the experiments, while the formation of butyrate mirrored that of butanol. 相似文献
23.
A fluorescent pigment was isolated from the culture fluid of Methanobacterium thermoautotrophicum strain H. This pigment was shown to be 7,8-didemethyl-8-hydroxy-5-deazariboflavin by various spectroscopic and chromatographic techniques. This compound was previously described as the FO acid hydrolysis fragment of coenzyme F420. On the basis of the time of appearance of the pigment in the course of fermentation, it is suggested that this substance may be an over-produced biosynthetic precursor of F420. 相似文献
24.
Summary Labelling of renal tubule cytosomes with electron dense iron granules can be attained by daily intramuscular injections to mice of an iron sorbitol citric-acid compound in a total of approximately 50 mg Fe+++/100 g of body weight. The labelled cytosomes correspond to secondary lysosomes and represent heterolysosomes or ambilysosomes. The evidence suggests that tubule and lysosome function are undisturbed by the labelling procedure. The use of this method for fine structural studies of the interaction between secondary lysosomes and other cytoplasmic organelles and elements is indicated.Microbodies do not incorporate administered Fe+++. The morphological observations support the opinion that these bodies are formed in specialized portions of the smooth surfaced endoplasmic reticulum of proximal tubule cells.Supported in part by grants from the Swedish Medical Research Council (Projects No. K 67-12x-1006-2, B 67-12x-1006-02K, K 68-12x-1006-03, and B 69-12x-1006-04A). The assistance of Miss Silwa Mengarelli and Miss Britt-Marie Pettersson is gratefully acknowledged. 相似文献
25.
FURTHER STUDIES ON THE INDUCTION OF THE DRUG-HYDROXYLATING ENZYME SYSTEM OF LIVER MICROSOMES
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Sten Orrenius 《The Journal of cell biology》1965,26(3):725-733
Further studies of the induction of the liver microsomal drug-hydroxylating enzyme system by pretreatment of rats with various drugs are presented. The phenobarbital-induced increase in the microsomal content of CO-binding pigment and in the activities of TPNH-cytochrome c reductase and the oxidative demethylation of aminopyrine is proportional, within certain limits, to the amount of phenobarbital injected. Removal of the inducer results in a parallel decrease in the levels of CO-binding pigment, TPNH-cytochrome c reductase, and aminopyrine demethylation. Other inducing drugs have been investigated and shown to act similarly to phenobarbital. The early increase in these enzymes is found in the microsomal subfraction consisting of rough-surfaced vesicles, whereas repeated administration of the inducing drug results in a concentration of the enzymes in the smooth-surfaced vesicles. The phenobarbital-stimulated formation of endoplasmic membranes is reflected in increased amounts of the various microsomal phospholipid fractions as revealed by thin layer chromatography. There is no significant difference between the stimulated rates of Pi32 incorporation into phospholipids of the two different microsomal subfractions in response to phenobarbital treatment. The drug-induced enzyme synthesis is unaffected by adrenalectomy. 相似文献
26.
Summary To investigate whether anti-(carcinoembryonic antigen) monoclonal antibodies (mAb) react with single or repeated epitopes, sandwich radioimmunoassays in homologous and heterologous combinations were performed. Four mAb (I-27, I-47, II-17 and to some degree II-16) gave homologous binding while two mAb (I-38S1 and II-10) did not. Taken together with previous immunoprecipitation studies we conclude that all these mAb except II-10 react with repeated epitopes. The relative positions of the epitopes recognized by these mAb and of three additional mAb (II-6, II-7 and CB-CEA-1) were investigated using a plate antibody competition test with enzyme-labelled carcinoembryonic antigen (CEA). mAb I-38S1, II-6, II-7, II-10, II-16 and CB-CEA-1 were mutually cross-reactive, and were classified as belonging to one epitope group. mAb I-27 and I-47 fell outside this group and did not interfere with the binding of CEA conjugate to mAb II-17 either. They therefore represent a second epitope group. mAb II-17 showed no interference with the binding of CEA to any of the other mAb and must therefore represent a third epitope group. The slopes of the plate antibody competition curves were used for calculation of a correlation matrix, which in turn was used to depict the relative positions of the epitopes recognized by the mAb in the large group. 相似文献
27.
Morphological variability of geographically distinct populations of the estuarine copepod Acartia Tonsa 总被引:1,自引:1,他引:0
Garmew Tanya G. Hammond Susan Mercantini Amy Morgan Jessica Neunert Cindy Fornshell John A. 《Hydrobiologia》1994,(1):149-156
Variations in the number of spines on the left and right posterior dorsal and posterior margins of the prosome as well as the length of the prosome of Acartia tonsa from three estuaries, the upper western side of the Chesapeake Bay, Montauk Bay near the eastern end of Long Island Sound and the coast of Peru were determined. The length of the prosome and number of spines in each of the four locations were used as an indication of morphological similarity between the populations. 相似文献
28.
Jessica N. Hightower Dolly L. Crawford Wayne E. Thogmartin Kyle R. Aldinger Sara Barker Swarthout David A. Buehler John Confer Christian Friis Jeffery L. Larkin James D. Lowe Martin Piorkowski Ronald W. Rohrbaugh Kenneth V. Rosenberg Curtis Smalling Petra B. Wood Rachel Vallender Amber M. Roth 《Diversity & distributions》2023,29(2):254-271
Aim
Climate change is affecting the distribution of species and subsequent biotic interactions, including hybridization potential. The imperiled Golden-winged Warbler (GWWA) competes and hybridizes with the Blue-winged Warbler (BWWA), which may threaten the persistence of GWWA due to introgression. We examined how climate change is likely to alter the breeding distributions and potential for hybridization between GWWA and BWWA.Location
North America.Methods
We used GWWA and BWWA occurrence data to model climatically suitable conditions under historical and future climate scenarios. Models were parameterized with 13 bioclimatic variables and 3 topographic variables. Using ensemble modeling, we estimated historical and modern distributions, as well as a projected distribution under six future climate scenarios. We quantified breeding distribution area, the position of and amount of overlap between GWWA and BWWA distributions under each climate scenario. We summarized the top explanatory variables in our model to predict environmental parameters of the distributions under future climate scenarios relative to historical climate.Results
GWWA and BWWA distributions are projected to substantially change under future climate scenarios. GWWA are projected to undergo the greatest change; the area of climatically suitable breeding season conditions is expected to shift north to northwest; and range contraction is predicted in five out of six future climate scenarios. Climatically suitable conditions for BWWA decreased in four of the six future climate scenarios, while the distribution is projected to shift east. A reduction in overlapping distributions for GWWA and BWWA is projected under all six future climate scenarios.Main Conclusions
Climate change is expected to substantially alter the area of climatically suitable conditions for GWWA and BWWA, with the southern portion of the current breeding ranges likely to become climatically unsuitable. However, interactions between BWWA and GWWA are expected to decline with the decrease in overlapping habitat, which may reduce the risk of genetic introgression. 相似文献29.
30.
David Julian Arias-Chávez Patrick Mailloux-Salinas Jessica Ledesma Aparicio Elihu Campos-Pérez Omar Noel Medina-Campos José Pedraza-Chaverri Guadalupe Bravo 《Journal of cellular and molecular medicine》2023,27(20):3147-3156
Benign prostatic hyperplasia (BPH) is the most common adenoma in old men. Tomatoes are a rich source of bioactive compounds that, as well as selenium (Se), possess antioxidant and antiproliferative activity. The aim was to evaluate the therapeutic effect of Se in combination with a tomato extract in aged rats with BPH. Aged male Wistar rats were divided in the following groups (n = 10 rats/group): Control (C), BPH, BPH + Finasteride (BPH + F), BPH + Tomato Lipidic Extract (BPH + E), BPH + Selenium (BPH + S) and BPH plus E plus S (BPH + E + S). After 4 weeks of treatment, prostate weight, diuresis, antioxidants enzymes, prooxidants and inflammatory markers, growth factors and androgens were determined. BPH + E + S reduced prostate weight by 59.29% and inhibited growth by 99.35% compared to BPH + F which only decreased weight and inhibited growth by 15.31% and 57.54%, respectively. Prooxidant markers were higher with BPH + F (49.4% higher vs. BPH), but BPH + E + S decreased these markers (94.27% vs. BPH) and increased antioxidant activity. Finally, diuresis was higher with the BPH + E + S combination and markers of inflammation and growth factors were significantly lower with respect to BPH + F. Our findings provide a beneficial and protective therapeutic option of E + S directed against androgens, oxidative stress and inflammation that regulates cell proliferation in the prostate gland. 相似文献