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71.
Abstract. Settlement timing and differential settlement for the larval stage of the green sea urchin, Strongylocentrotus droebachiensis , in the southern Gulf of Maine was studied during the summer of 1996. Settlement densities on astroturf panels were highest in June and early July (13 to 37 m −2 d−1 ), and peaked in mid-June (199 m−2 d−1 ). Settlement was low to nonexistent from mid-July through August (0 to 2 m−2 d−1 ). During the peak in settlement, no selection for substrate type was observed. In the remainder of the settlement period, differential settlement occurred, with a preference for substrate covered with live coralline algae. Test diameter of newly settled urchins varied among the substrates, with urchins settling on live coralline algae having the largest test diameter (0.43 ± 0.01 mm). There were no differences in test diameter among the different weeks in which sampling was done. Sustained onshore winds occurred only during peak settlement, suggesting that wind drift currents may concentrate larvae and influence patterns of larval settlement. 相似文献
72.
73.
74.
Complex nonadditive interactions between specific alleles at multiple loci may underlie many so-called multifactorial threshold
birth defects. The open-eyelids-at-birth defect in mice is a good model for these defects, and an understanding of its genetic
complexity begins with mapping the participating loci. The open-eyelids defect can be part of a syndrome or can occur with
no other obvious phenotypic effects. Of the latter nonsyndromic forms, the lidgap series includes four extant mutations that
are considered to be alleles based on complementation tests. All show genetic complexity in segregation ratios. None has been
mapped previously. On the basis of a strategy of mapping the mutation with the simplest inheritance pattern first, we generated
an extensive exclusion map for lidgap-Gates, lg
Ga
, using morphological and protein polymorphisms. We then screened the non-excluded regions in a congenic strain, AEJ.LGG—lg
Ga
, for SSLP markers and located the differential chromosome segment containing the lg
Ga
locus in a region near the distal end of mouse Chromosome (Chr) 13. This linkage was confirmed and refined by typing SSLPs
in 64 F2 and 74 BC1 progeny of a cross of LGG/Bc (lg
Ga
/lg
Ga
) to SWV/Bc. The lg
Ga
mutation maps to a 1- to 2-cM region between D13Mit76 and D13Mit53. Integrin alpha 1 and integrin alpha 2, which map to the same general region, are possible candidate loci, based on their
embryonic expression and cellular function. Evidence is also presented for a common unlinked recessive suppressor of the open
eyelids trait caused by lg
Ga
.
Received: 3 February 1995 / Accepted: 19 February 1996 相似文献
75.
K Orchard N Perkins C Chapman J Harris V Emery G Goodwin D Latchman M Collins 《Biochemical Society transactions》1990,18(4):555-556
76.
Transient increase in phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol trisphosphate during activation of human neutrophils 总被引:13,自引:0,他引:13
A E Traynor-Kaplan B L Thompson A L Harris P Taylor G M Omann L A Sklar 《The Journal of biological chemistry》1989,264(26):15668-15673
We recently showed that phosphatidylinositol trisphosphate (PIP3) was present in a unique lipid fraction generated in neutrophils during activation. Here, we demonstrate that the band containing this fraction isolated from thin layer chromatography consists primarily of PIP3 and that only small amounts of radiolabeled PIP3 exist prior to activation. In addition, high performance liquid chromatography of deacylated phospholipids from stimulated cells reveals an increase in a fraction eluting ahead of glycerophosphoinositol 4,5-P2. After removal of the glycerol we found that it coeluted with inositol 1,3,4-P3 when resubjected to high performance liquid chromatography. Thus, we have detected a second, novel form of phosphatidylinositol bisphosphate in activated neutrophils, PI-(3,4)P2. The elevation of PIP3 through the formyl peptide receptor is blocked by pretreatment with pertussis toxin, implicating mediation of the increase in PIP3 by a guanosine triphosphate-binding (G) protein. The rise in PIP3 is not secondary to calcium elevation. Buffering the rise in intracellular calcium did not diminish the increase in PIP3. The elevation of PIP3 appears to occur during activation with physiological agonists, its level varying with the degree of activation. Leukotriene B4, which elicits many of the same responses as stimulation of the formyl peptide receptor but with minimal oxidant production, stimulates a much attenuated rise in PIP3. Isoproterenol, which inhibits oxidant production also reduces the rise in PIP3. Hence formation of PI(3,4)P2 and PIP3 (presumed to be PI(3,4,5)P3) correlates closely with the early events of neutrophil activation. 相似文献
77.
A format for the structure-oriented analysis of immunoglobulin (Ig) variable region sequences is presented and applied to generate sequence profiles for comparison of heavy- and light-chain subgroups. The profile allows simultaneous evaluation of sequences and structural information and can be used for a number of different applications. 相似文献
78.
Keith M. Harris Jia-Jia Syu Owen D. Lello Y. L. Eileen Chew Christopher H. Willcox Roger H. M. Ho 《PloS one》2015,10(6)
There is considerable need for accurate suicide risk assessment for clinical, screening, and research purposes. This study applied the tripartite affect-behavior-cognition theory, the suicidal barometer model, classical test theory, and item response theory (IRT), to develop a brief self-report measure of suicide risk that is theoretically-grounded, reliable and valid. An initial survey (n = 359) employed an iterative process to an item pool, resulting in the six-item Suicidal Affect-Behavior-Cognition Scale (SABCS). Three additional studies tested the SABCS and a highly endorsed comparison measure. Studies included two online surveys (Ns = 1007, and 713), and one prospective clinical survey (n = 72; Time 2, n = 54). Factor analyses demonstrated SABCS construct validity through unidimensionality. Internal reliability was high (α = .86-.93, split-half = .90-.94)). The scale was predictive of future suicidal behaviors and suicidality (r = .68, .73, respectively), showed convergent validity, and the SABCS-4 demonstrated clinically relevant sensitivity to change. IRT analyses revealed the SABCS captured more information than the comparison measure, and better defined participants at low, moderate, and high risk. The SABCS is the first suicide risk measure to demonstrate no differential item functioning by sex, age, or ethnicity. In all comparisons, the SABCS showed incremental improvements over a highly endorsed scale through stronger predictive ability, reliability, and other properties. The SABCS is in the public domain, with this publication, and is suitable for clinical evaluations, public screening, and research. 相似文献
79.
The protein kinase inhibitors 2-aminopurine (2-AP) and 6-dimethylaminopurine (6-DMAP) were used to examine the effects of protein dephosphorylation on the control of mitosis in mammalian cells. Both 2-AP and 6-DMAP induced premature mitosis in hamster fibroblasts that were arrested in S phase. This response was characterized by changes in cell morphology, breakdown of the nuclear envelope, and premature chromosome condensation. Premature mitosis was followed by a return to interphase morphology and reformation of the nuclear envelope around decondensed and fragmented chromatin to form numerous micronuclei. The activity of both compounds was dependent upon new protein synthesis but not new RNA synthesis. 2-AP and 6-DMAP acted cooperatively with each other and with caffeine, suggesting a common mechanism of action. In exponentially growing cells, 2-AP and 6-DMAP did not induce premature mitosis but did increase the frequency of binucleated cells by blocking cytokinesis. These findings support a role for protein dephosphorylation in the control of mitosis and indicate that cell cycle perturbations can modify this regulation. 相似文献
80.
Paul W. R. Harris Margaret A. Brimble 《International journal of peptide research and therapeutics》2012,18(1):63-70
As a first step towards the preparation of a functional biomolecule, a chemical synthesis of the collagenous domain of adiponectin
is described. The 76 residue polypeptide (without post-translational modifications) could be assembled efficiently from smaller
unprotected peptides using two native chemical ligation reactions followed by a reductive desulfurisation step. In turn, the
polypeptides were synthesised in high purity by microwave enhanced solid phase synthesis. 相似文献