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981.
Angie Rizzino Alan B. Blumenthal 《In vitro cellular & developmental biology. Plant》1978,14(5):437-442
Summary We synchronized Drosophila cell lines (Schneider's line 2 and Kc) by allowing the cells to enter the stationary phase of growth and then diluting them into fresh culture medium. The cells
of both cell lines entered S phase, after an 8- to 14-hr delay, in a state of partial synchrony; 60 to 80% of the cell population
accumulated in S phase. Measurements of the cell cycle phases of Schneider's line 2 cells (S=14 to 16 hr; G2=6 to 8 hr; M=0.4 hr) were similar to those of Kc cells.
This work was performed under the auspices of the U.S. Energy Research and Development Administration. A.R. was supported
by an NIH post-doctoral fellowship, No. CA01060. 相似文献
982.
R. H. Goodwin G. J. Tompkins P. McCawley 《In vitro cellular & developmental biology. Plant》1978,14(6):485-494
Summary A series of cell lines unique in insect virus susceptibility pattern have been isolated from the ovaries of the gypsy moth
(Lymantria dispar: Lepidoptera: Lymantriidae) on a synthetic medium with mammalian and avian serum supplementation. Growth curves showed the
poorest growth occurring on peptone-based media with somewhat better growth on amino-acid-based media. The best growth was
obtained with combined media. Serological study distinguished the present cell lines from one another and from cell lines
derived from other insect species grown routinely in the same laboratory. Baculovirus susceptibility among the new lines varied
from no response to a specific complete replication response upon challenge by the homologous (gypsy moth) nuclear polyhedrosis
virus.
This research was funded in part through a reimbursable agreement with the U.S. Forest Service. 相似文献
983.
Lightbody James J. Peterson Ward D. Poulik M. D. 《In vitro cellular & developmental biology. Plant》1978,14(5):465-468
Summary The DAUDI lymphoblast cell line derived from a patient with Burkitt lymphoma was obtained from two different sources. One
of these (DAUDI-I) produced a factor that inhibited lymphocyte proliferation in both human and mouse regardless of the stimulator,
i.e. allogeneic lymphocytes or mitogens. Glutaraldehyde treatment eliminated production of the factor and demonstrated that
DAUDI-I was capable of stimulating normal lymphocytes in MLR. A second DAUDI cell line (DAUDI-S) did not produce the inhibitory
factor and was capable of MLR stimulation.
Supported by the Children's Leukemia Foundation of Michigan, NIH Grants AI 11013 and AI 11335, and the Kidney Foundation of
Michigan. 相似文献
984.
Ubaldo Armato Paola G. Andreis Enrica Draghi Loreta Mengato 《In vitro cellular & developmental biology. Plant》1978,14(6):479-484
Summary Studies employing [3H]thymidine and radioautography as well as colchicine and Feulgen staining of DNA showed that up to 19-fold increases in the
degree of cell crowding in vitro, i.e. from 1.45 to 27.55×104 cells per specimen, did not change the rates of entry into DNA synthesis and mitosis of cultivated primary neonatal rat hepatocytes. 相似文献
985.
986.
SYNOPSIS Triplet conjugants of Paramecium caudatum which appeared naturally in mating mixtures and those of Paramecium multimicronucleatum which were produced by conjugation-inducing chemicals were isolated. Triplet conjugants lasting for more than 3 h were stained to examine macronuclear events. In P. caudatum , only 2 triplets among 182 (1%) contained macronuclear fragmentation in all 3 members. The most frequently occurring triplets (79%) were those producing 1 cell without and 2 cells with macronuclear fragments. There were also triplets (17%) producing 1 cell with, and 2 without macronuclear fragments, and some (3%) with 3 cells that contained no fragments. The length of persistence of the triplet was not responsible for the occurrence of macronuclear fragmentation in the 3rd cell of the triplet. In P. multimicronucleatum , the same 4 classes of triplets occurred, but the most frequently occurring class was that consisting of 3 cells (91%) with macronuclear fragments. Induction of nearly 100% of triplets with 3 such cells was possible by isolating the triplets' from a culture which was treated chemically at about 24 h after the last feeding. Treatment with chemicals in starved cultures resulted in triplets with incompletely fragmented or nonfragmented macronuclei. Further, in P. multimicronucleatum , chemicallyinduced triplets involving only holdfast pairs to which the 3rd cells were uniting often produced 3 cells with fragmented macronuclei. 相似文献
987.
The Nile catfish, Clarias lazera was found to concentrate radioactive cesium-134 and cobalt-6o from the aquatic environment. For cesium-134 the rate of uptake increased by increase of exposure time, while for cobalt-6o maximum uptake occurred after one day of exposure. The corresponding concentration factors at maximum uptake levels were 0.37 and 0.36 for cesium and cobalt respectively.The internal distribution of these radionuclides in the different tissues and organs of the fish due to uptake from the aquatic environment followed the decreasing order:For 134Cs: muscle, bone, gills, stomach, kidneys, intestine and liver.For 60Co: bone, muscle, gills, intestine, kidneys, stomach and liver.The internal distribution due to ingestion of these radionuclides followed nearly the same order as was found in case of uptake from the aquatic environment. 相似文献
988.
The ultrastructure of 4 species of the calcareous, siphonaceous alga Halimeda (H. cylindracea Decaisne, H. discoidea Decaisne, H. macroloba Decaisne and H. tuna (Ellis & Solander) Lamour) has been studied, and the observed changes during growth and development are related to changes in the degree of calcification. A distinct gradient in the types and quantities of cell organelles exists in a growing apical filament. As these filaments grow, branch, and eventually develop into a mature segment, changes in the organization of organelles such as mitochondria and chloroplasts are observed. Calcification begins when the chloroplasts reach structural maturity and when the peripheral utricles adhere (fuse). This adhesion of the peripheral utricles isolates the intercellular space (ICS) in which calcification occurs from the external seawater. Calcification begins in the outermost (pilose) cell wall layer of the walls facing into the ICS. The cell walls at the thallus exterior undergo extensive changes after utricular fusion; the pilose layer is lost, the cuticles of adjacent utricles fuse forming a ridge at their junction, and multiple cuticles are formed. The aragonite (CaCO3) crystals which are initially precipitated within the pilose wall layer, rapidly increase in size and number, eventually filling much of the ICS. Only the initial nucleation of aragonite is associated with the pilose wall layer, the later precipitation of aragonite is totally independent of the pilose layer. In older segments secondary deposition of CaCO3 also occurs around existing aragonite needles. 相似文献
989.
Edward G. Durbin 《Journal of phycology》1977,13(2):150-155
The effect of cell size on growth rates and some cellular contents of Thalassiosira nordenskioeldii Cleve has been measured at 0 and 10 C. At 0 C the growth rate did not vary with cell size. The 2 smallest clones at this temperature had reduced growth rates because of the induction of sexuality in that size range. The clones grown at 10 C showed a significant negative relationship between growth rate and valve diameter with the cell surface area/volume ratio positively related to growth rate. At both temperatures the smaller cells had proportionately more carbon and nitrogen/unit cell volume. The amount of chlorophyll a and silica/unit cell surface area increased with increasing cell surface area at both 0 and 10 C. Both the C/N and C/chl a ratios showed no significant change with cell size at either temperature but there was a significant increase in the C/chl a ratio at 0 C. The C/Si ratio decreased with increasing cell size at both 0 and 10 C. 相似文献
990.
Alonzo H. Ross Harden M. McConnell 《Biochemical and biophysical research communications》1977,74(4):1318-1325
Band 3, the erythrocyte membrane protein thought to be responsible for anion transport, was purified to near homogeneity using a Concanavalin A affinity column. Band 3 was then combined with egg lecithin, erythrocyte lipid, cholesterol, and glycophorin, the major erythrocyte sialoglycoprotein, to form vesicles capable of rapid sulfate transport. The transport activity was sensitive to prior treatment of the erythrocytes with pyridoxal phosphate-NaBH4, a potent inhibitor of anion transport in these cells. 相似文献