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51.
52.
Franz Boas's study of the changes in bodily form of descendants of immigrants has stood for over ninety years as proof of environmental influences on cranial form. Recent reanalysis of his data have shown differing interpretations of the importance of his findings. Here, we explore the historical, political, and social setting of the study that could have led Boas to overstate the importance of his findings. We also include a discussion of the issue at large with respect to the study of modern and prehistoric human variation. Given the current state of population research using craniometric data we conclude, as many of Boas's early criticism have, that while some of the changes observed by Boas have statistical credibility, they generally lack biological meaning when considered in the scope of the degree of modern human variation. [Keywords: plasticity, immigration, craniometries, cranial index, human variation] 相似文献
53.
Yates IE Widstrom NW Bacon CW Glenn A Hinton DM Sparks D Jaworski AJ 《Mycopathologia》2005,159(1):65-73
Fusarium verticillioides is an important fungus occupying dual roles in the maize plant. The fungus functions as an endophyte, a fungal/host interaction beneficial to the growth of some plants. At other times, the fungus may function as a mycotoxin producing pathogen. The advantages and/or disadvantages of the endophytic relationship must be established in order to target appropriate sites for controlling diseases and mycotoxins in maize. One possibility could be to ensure seed maize is fungal free prior to planting. Reciprocal inoculations were made with two fungal isolates on seed of two maize genotypes. Yield was measured at harvest by ear and seed characters and vegetative growth at one-month intervals for plant survival, height, weight and stem diameter. Yield and vegetative growth differed among mature plants only once based on seed inoculation status. In 1998, plant weight was reduced and seed weight per ear was increased for the dent maize, GT-MAS: gk, grown from F. verticillioides RRC 374- inoculated seed compared to other seed treatments. Most vegetative characters were reduced at the first collection for Silver Queen plants grown from F. verticillioides-inoculated seed in 1997 and 1999, but not in 1998. However, no significant differences occurred among mature Silver Queen plants during any of the three growing seasons. In conclusion, yield and vegetative growth of mature maize plants grown from F. verticillioides-inoculated seed were equal to or greater than plants grown from non-inoculated seed under south Georgia field conditions during 1997, 1998, and 1999. 相似文献
54.
Prostaglandin H synthase (PGHS) is an autocatalytic enzyme which plays a key role in the arachidonic acid metabolic pathway.
PGHS mediates the formation of prostaglandin H2, the precursor for a number of prostaglandins which are important in a wide variety of biological processes, including inflammation,
blood clotting, renal function, and tumorigenesis. Here we present a Michaelis-Menten-style model for PGHS. A stability analysis
determines when the reaction becomes self-sustaining, and can help explain the regulation of PGHS activity in vivo. We also
consider a quasi-steady-state approximation (QSSA) for the model, and present conditions under which the QSSA is expected
to be a good approximation. Applying the QSSA for this model can be useful in computationally intensive modeling endeavors
involving PGHS. 相似文献
55.
J.C.?WilliEmail author J.O.?Mountford T.H.?Sparks 《Biodiversity and Conservation》2005,14(13):3215-3233
The last five decades have witnessed an intensification of agriculture with a marked increase in the use of agrochemicals.
This study investigated whether arable edges affect ancient woods and the extent of any modifications to the ground flora.
Plant species were recorded from a total of 84 transects into the centre of the woods, of which 59 were taken from the arable–woodland
interface and 25 were taken from non-arable land or woodland rides. Ellenberg indicator and CSR values were used to infer
fertility and features of the environment. Results suggested that, after adjusting for light and moisture conditions, elevated
nitrogen levels might occur in ancient woodlands to a distance of at least 100 m from arable farmland. Furthermore, the transects
from the arable fields had a substantially altered herb-layer with respect to species composition, notably a greater percentage
cover of ruderal and nitrophilous species, and a lower cover of stress tolerator species. Smaller woods contained a greater
cover of competitor and nitrophilous species and a lower cover of stress tolerators and ancient woodland indicator species.
We conclude that farming may be unwittingly modifying the ground flora of ancient woodlands adjacent to arable land and that
small and irregularly shaped woods are most at risk. It is recommended that farmers apply agrochemicals in such a way that
drift is minimised, and that large, valuable ancient woods be protected by a substantial buffer zone. 相似文献
56.
Sparks AK 《Journal of invertebrate pathology》2005,89(1):67-77
This paper discusses diseases of commercially important non-insect invertebrates from both a historical and a personal perspective. Early studies of curious scientists such as Metchnikoff using invertebrate systems led to important discoveries with much wider impact. As commercial culture of oysters, shrimp, and other invertebrates grew, so did studies of their diseases. Here, the impact of pioneering scientists and important new techniques on our understanding of these diseases is described. 相似文献
57.
Woods YL Xirodimas DP Prescott AR Sparks A Lane DP Saville MK 《The Journal of biological chemistry》2004,279(48):50157-50166
Here we demonstrate a novel p53-independent interaction between the nucleolar tumor suppressors, p14 Arf and Werners helicase (WRN). Binding of p14 Arf to WRN is multivalent and resembles the binding of p14 Arf to Mdm2. Residues 2-14 and 82-101 of p14 Arf and residues in the central region and C terminus of WRN have particular importance for binding. p14 Arf promotes small ubiquitin-like modifier (SUMO) modification of WRN in a synergistic manner with the SUMO-conjugating enzyme, UBCH9. p14 Arf causes redistribution of WRN within the nucleus, and this effect is reversed by expression of a SUMO-specific protease, thus implicating the SUMO conjugation pathway in WRN re-localization. We establish that the ability to promote SUMO conjugation is a general property of the p14 Arf tumor suppressor. 相似文献
58.
Objective: Previous research has addressed the relationship between BMI and chronic disease in primary care; however, little has been done with regard to the association between obesity and depression in primary care. The purpose of this paper is to assess the relationship between obesity and chronic conditions including depression. Research Methods and Procedures : Data from primary care patients seen at a university‐based family medicine clinic in the southeastern United States were extracted for the time between January 1, 1999 and January 1, 2002. Data extracted included most recent height and weight, age, ethnicity, pregnancy status, number of office visits, blood pressure, cholesterol, hemoglobin A1C, current diagnoses, and medications. Results : A total of 8197 patients were included in the analysis. Sixty‐nine percent of patients seen in a 3‐year period were either overweight or obese. Comparing blood pressure, cholesterol, diagnoses, and medications between BMI groups found differences in virtually all categories. Diagnoses of high cholesterol, hypertension, diabetes, and depression significantly increased for obese patients. Discussion : Obese patients are over‐represented in primary care, and this over‐representation of obesity correlates with several diagnoses, including depression. Depression is a chronic disease that may interfere with health‐related behaviors and must be addressed within the health care system. 相似文献
59.
Ala PJ Gonneville L Hillman M Becker-Pasha M Yue EW Douty B Wayland B Polam P Crawley ML McLaughlin E Sparks RB Glass B Takvorian A Combs AP Burn TC Hollis GF Wynn R 《The Journal of biological chemistry》2006,281(49):38013-38021
Structural analyses of the protein-tyrosine phosphatase 1B (PTP1B) active site and inhibitor complexes have aided in optimization of a peptide inhibitor containing the novel (S)-isothiazolidinone (IZD) phosphonate mimetic. Potency and permeability were simultaneously improved by replacing the polar peptidic backbone of the inhibitor with nonpeptidic moieties. The C-terminal primary amide was replaced with a benzimidazole ring, which hydrogen bonds to the carboxylate of Asp(48), and the N terminus of the peptide was replaced with an aryl sulfonamide, which hydrogen bonds to Asp(48) and the backbone NH of Arg(47) via a water molecule. Although both substituents retain the favorable hydrogen bonding network of the peptide scaffold, their aryl rings interact weakly with the protein. The aryl ring of benzimidazole is partially solvent exposed and only participates in van der Waals interactions with Phe(182) of the flap. The aryl ring of aryl sulfonamide adopts an unexpected conformation and only participates in intramolecular pi-stacking interactions with the benzimidazole ring. These results explain the flat SAR for substitutions on both rings and the reason why unsubstituted moieties were selected as candidates. Finally, substituents ortho to the IZD heterocycle on the aryl ring of the IZD-phenyl moiety bind in a small narrow site adjacent to the primary phosphate binding pocket. The crystal structure of an o-chloro derivative reveals that chlorine interacts extensively with residues in the small site. The structural insights that have led to the discovery of potent benzimidazole aryl sulfonamide o-substituted derivatives are discussed in detail. 相似文献
60.