全文获取类型
收费全文 | 755篇 |
免费 | 60篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 24篇 |
2014年 | 42篇 |
2013年 | 42篇 |
2012年 | 44篇 |
2011年 | 41篇 |
2010年 | 20篇 |
2009年 | 17篇 |
2008年 | 33篇 |
2007年 | 24篇 |
2006年 | 36篇 |
2005年 | 38篇 |
2004年 | 32篇 |
2003年 | 36篇 |
2002年 | 34篇 |
2001年 | 20篇 |
2000年 | 18篇 |
1999年 | 22篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1992年 | 17篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1968年 | 6篇 |
1967年 | 4篇 |
1965年 | 3篇 |
排序方式: 共有815条查询结果,搜索用时 15 毫秒
1.
Emma Bricchi Marco Fornaciari Claudia Giannoni Francesca Greco Daniela Fascini Giuseppe Frenguelli Gianfranco Mincigrucci Bruno Romano 《Aerobiologia》1992,8(3):401-406
Summary Gramineae pollination from a pollen monitoring station located in the eastern suburb of Perugia and meteorological correlations are reported. The data refers to the year 1989. Grass pollen peak pollination was from May to July; in this period the influence of relative humidity and of temperature on pollen concentration was very high. Phenological observations, to identify the time of maximum stamen extension in the most common genera in the area, are also reported. During the period of investigation the counts of pollen grains over four-hour periods showed a regular diurnal rhythm with peaks of concentration in the four-hour period 16.00–20.00. Aerosporological data and meteorological data related to four-hour periods were correlated following different criteria. 相似文献
2.
T Barreca R Franceschini C Siani A Cataldi N Francaviglia C Silvestro E Rolandi 《Hormone research》1991,35(6):239-241
Arginine vasopressin (AVP) concentrations were determined in plasma and in cerebrospinal fluid (CSF) in 8 adult male patients suffering from hydrocephalus of various etiologies, before and after intravenous administration of 10 mg metoclopramide. Metoclopramide was able to increase the plasma (2.6 +/- 0.2 ng/l in basal conditions and 6.1 +/- 0.6 ng/l at 30 min) but not the CSF AVP levels. The results suggest that the neurons which secrete AVP into the CSF may be functionally different from those secreting into the peripheral circulation. 相似文献
3.
The DNA of fifteen Italian cultivars of durum wheat (Triticum turgidum L. ssp. durum) were analyzed by in fluorescence amplified fragment length polymorphism (fAFLP) in order to obtain the characteristic fingerprintings
of genotypes and assess their genetic relatedness. Among 64 combinations of fluorescence labelled primers, three different
combinations were chosen as producing a total of 6630 AFLP fragments, 2277 (34.3 %) of them being polymorphic. By using this
fAFLP methodology a DNA fingerprinting of each durum wheat cultivar was generated for genotype identification. Analysis of
the genetic relationships show the low variability among durum wheat cultivars. 相似文献
4.
A Bobba I Munno B Greco N M Pellegrino P Riccio E Jirillo E Quagliariello 《Biochemical and biophysical research communications》1991,180(2):1125-1129
We have applied a double tagging system in order to study whether purified myelin basic protein is able to adhere to normal human peripheral T lymphocytes without the need to purify cells. Evaluation of myelin basic protein adherence to peripheral blood mononuclear cells was determined with biotinylated myelin basic protein and fluoresceinated avidin, and lymphocyte population was identified by the corresponding phycoerythrinated monoclonal antibody. The observed adherence of myelin basic protein to T lymphocytes was found to depend on protein conformation. 相似文献
5.
6.
7.
The circadian rhythm of the N-terminus and C-terminus of the atrial natriuretic factor prohormone 总被引:1,自引:0,他引:1
D L Vesely E L Kanabrocki R B Sothern L E Scheving T H Tsai J Greco D L Bushell E Kaplan J Rumbyrt R P Sturtevant 《Chronobiology international》1990,7(1):51-57
Circadian variation in the circulating concentrations of the N-terminal and C-terminal portions of the atrial natriuretic factor prohormone (pro ANF) was evaluated in 8 men, ages 41-47, who have been followed for 19 years with respect to circadian variation in physiological variables including blood pressure and clinical chemistries. The N-terminus of the ANF prohormone contains two peptides consisting of amino acids 1-30 and 31-67 while the C-terminus contains 1 peptide (amino acids 99-126) of this 126 amino acid prohormone which lower blood pressure and have natriuretic properties. To determine if either the N-terminus and/or the C-terminus of the prohormone have a circadian variation in their circulating plasma concentrations these 8 men had blood samples obtained for radiommunoassay every 3 hr during a 24-hr period. Three radiommunoassays which immunologically recognize (1) the whole N-terminus (i.e. amino acids 1-98), (2) the midportion of the N-terminus (amino acids 31-67) and (3) the C-terminus (amino acids 99-126) of the ANF prohormone were utilized. The whole N-terminus, the midportion of the N-terminus which circulates after being proteolytically cleaved from the rest of the N-terminus, and the C-terminus each had a peak circulating concentration between 0400 and 0700 which were significantly (P less than 0.001) higher than their concentrations at any other time throughout the 24-hr period.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
E. L. Kanabrocki R. B. Sothern L. E. Scheving F. Halberg J. E. Pauly J. J. Greco B. A. Nemchausky M. Debartolo E. Kaplan J. B. McCormick J. H. Olwin G. E. Marks T. Bird D. P. Redmond R. C. Graeber A. Ferrara W. J. M. Hrushesky 《Chronobiology international》1988,5(3):237-284
At 3-hr intervals over a 24-hr span, 36 systemic, serologic and urinary variables were examined in 7 men in their mid 20's in the Spring of 1969, and again in the same 7 men in the Spring of 1979 under a similar chronobiologic protocol, using the same chemical and numerical analytical procedures. The variables examined for rhythms by cosinor were: vital signs--blood pressure (systolic, diastolic, pulse pressure and mean arterial pressure), heart rate, intraocular pressure (left and right), oral temperature; serum components--albumin, albumin/globulin ratio, total bilirubin, calcium, carbon dioxide, chlorides, bilirubin, cholesterol, globulin, glucose, potassium, sodium, sodium/potassium ratio, transaminase, triglycerides, total protein, urea nitrogen; and urine components--calcium, calcium/magnesium ratio, creatinine, magnesium, pH, potassium, sodium, sodium/potassium ratio, urea clearance, urea nitrogen, volume and zinc. Although all subjects appeared clinically healthy in 1969 and in 1979, certain inter-study differences were observed in a number of rhythm parameters of different variables. Statistically significant increases in mesor for the group as a whole were observed for serum Ca, cholesterol, Cl, CO2, K, Na, and while statistically significant mesor decreases for a group as a whole were noted in serum glucose and transaminase. Statistically significant increases in amplitude for the group as a whole were observed in serum chloride and urinary Na/K ratio, while statistically significant decreases were observed in amplitude for blood pressure, heart rate, serum albumin, A/G ratio, globulin, glucose, protein, sodium and transaminase.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
Anna Maria Greco Pasquale Gambardella Raffaella Sticchi Diego D'aponte Pietro De Franciscis 《Chronobiology international》1988,5(3):217-225
Circadian rhythms of serotonin (5HT), its precursors tryptophan (TP) and 5-hydroxy-tryptophan (5HTP) and its acid catabolite 5-hydroxy-indoleacetic acid (5HIAA), were determined in the hypothalamus of control rats and rats which had been treated continuously with subcutaneous imipramine (10 mg/kg/day) for 2 weeks.
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.
Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations. 相似文献
10.
M H Carstens R J Greco D J Hurwitz D E Tolhurst 《Plastic and reconstructive surgery》1991,87(4):615-626
The anatomic boundaries and vascular supply of the subgaleal fascia have been described previously. The thin and malleable subgaleal fascia was selected for difficult reconstructive problems in seven patients. This flap has been based on either the supraorbital or the superficial temporal vascular leash. The subgaleal fascia is readily dissected from superficial galea and deep periosteum, leaving behind a well-vascularized scalp and a skin-graftable calvarium. The flap conforms to a cartilage framework for ear reconstruction. It takes a skin graft well. The subgaleal fascia can patch dural defects and fill sinus dead space. It has been used to augment facial contour. Free vascularized transfer of the subgaleal fascia has included the temporoparietal fascia, which was partially split from the subgaleal fascia for bilobed flap resurfacing of the hand. The subgaleal fascial flap should be considered when ultrathin, vascularized coverage is needed. 相似文献