全文获取类型
收费全文 | 691篇 |
免费 | 42篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 41篇 |
妇产科学 | 12篇 |
基础医学 | 96篇 |
口腔科学 | 30篇 |
临床医学 | 44篇 |
内科学 | 124篇 |
皮肤病学 | 16篇 |
神经病学 | 12篇 |
特种医学 | 144篇 |
外国民族医学 | 1篇 |
外科学 | 41篇 |
综合类 | 50篇 |
预防医学 | 37篇 |
眼科学 | 6篇 |
药学 | 35篇 |
中国医学 | 17篇 |
肿瘤学 | 32篇 |
出版年
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 18篇 |
2013年 | 35篇 |
2012年 | 27篇 |
2011年 | 20篇 |
2010年 | 43篇 |
2009年 | 48篇 |
2008年 | 24篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 13篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 35篇 |
1997年 | 33篇 |
1996年 | 34篇 |
1995年 | 36篇 |
1994年 | 24篇 |
1993年 | 20篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 17篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1955年 | 1篇 |
1950年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有739条查询结果,搜索用时 15 毫秒
61.
62.
63.
AA Lapillonne FH Glorieux BL Salle PM Braillon M Chambon J Rigo G Putet J Senterre 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(S405):117-122
Fat and mineral metabolic balance studies were performed in 25 normal very low-birth-weight infants ( 1500 g at birth) fed either pooled pasteurized human milk supplemented with calcium, phosphorus and magnesium, or a preterm formula. Calcium, phosphorus and magnesium intake were similar in both groups and averaged 100mg/kg/day, 72 mg/kg/day and 8 mg/kg/day, respectively. Calcium and phosphorus retention was higher in the subjects fed fortified human milk than in those receiving a preterm formula (65±14 and 62±9mg/kg/day versus 55±12 and 47±7mg/kg/day respectively). The difference was only significant for phosphorus. Magnesium retention was similar in the two groups and averaged 3 mg/kg/day. Fat intake and absorption was significantly higher in the preterm formula fed group than in the one fed fortified human milk (5.5±0.4 g/kg/day and 88±4% versus 4.2±1 g/kg/day, 79±6% respectively). Assessment of the whole body bone mineral content by dual energy X-ray absorptiometry was performed at 3 and 6 months of age in another group of 25 low-birth-weight infants fed either fortified human milk or a preterm formula. Whole body bone mineral content (BMCt) was low (43.3±30.8 g of hydroxyapatite) at 3 months of age (theoretical term) compared to normal full-term newborns at birth. There was no significant influence of the diet. At 6 months of age, BMCt reached 168.6±36.6g, a value similar to that of full-term newborns, with no significant difference between the two regimen groups. The deficit in the 12 subjects who had a BMCt under 30 g at 3 months of age had been corrected at age 6 months. Premature babies fed a pooled pasteurized human milk enriched with calcium, phosphorus and magnesium favored a better retention of calcium and phosphorus. However, no significant influence of the two diets studied was observed on the gain in BMCt over the first 6 months of life. 相似文献
64.
C. Boulanger NA Flavahan ZS Katusic K. Komori AA Vos and PM Vanhoutte MD Director 《Fundamental & clinical pharmacology》1990,4(5):525-538
Experiments were designed to determine the effect of CRL 41034, a buflomedil analogue, on the adrenergic responsiveness of canine veins. Rings of saphenous vein (without endothelium) were suspended for isometric tension recording in modified Krebs-Ringer bicarbonate solution at 37 degrees C. CRL 41034 produced a concentration-dependent inhibition of the contractions evoked by the alpha adrenergic agonists norepinephrine, phenylephrine and UK 14304 which was insensitive to the blockade of neuronal uptake by cocaine. CRL 41034 was more potent in inhibiting the concentration-dependent contractions evoked by UK 14304 than those by phenylephrine and the antagonism it caused against the response to UK 14304 fulfilled the criteria for competitivity. CRL 41034, at 10(-5) M significantly depressed, and at 10(-4) M abolished the contractions induced by electrical stimulation of the adrenergic nerves and those evoked by the indirect sympathomimetic amine tyramine. Strips of canine saphenous vein were superfused after incubation with [3H] norepinephrine. During sympathetic nerve activation, CRL 41304 increased the stimulation-evoked overflow of [3H] norepinephrine and 3-methoxy-4-dihydroxyphenylglycol; in the presence of rauwolscine the compound only increased the stimulation-evoked overflow of 3,4-dihydroxyphenylglycol. These experiments suggest that the major vascular effects of CRL 41034 in canine veins are blockade of alpha 2-adrenoceptors on vascular smooth muscle, and inhibition of prejunctional alpha 2-adrenoceptors on adrenergic nerve endings. 相似文献
65.
66.
Hinsch E; Ponce AA; Hagele W; Hedrich F; Muller-Schlosser F; Schill WB; Hinsch KD 《Human reproduction (Oxford, England)》1997,12(8):1673-1681
Binding of mammalian spermatozoa to the zona pellucida and the induction of
the acrosome reaction are prerequisites for successful oocyte
fertilization. It has been postulated that xenobiotics that are released in
the environment as well as exposure to pharmaceutical medications may be
associated with reproductive problems in men and wildlife. Examining
physiological and non-physiological effects of particular compounds on
sperm functions requires high quality in-vitro test systems. We established
a reliable combined in-vitro test system with bovine gametes and evaluated
if aliquots of pooled post-thaw spermatozoa are suitable for examining
essential sperm functions. Using cryopreserved semen, the PSA-FITC/Hoechst
33258 staining procedure was applicable to evaluate the acrosomal status
and cell viability. In the bovine hemizona assay, hemizona indices revealed
no differences between cryopreserved and fresh semen. Treatment of
post-thaw bovine spermatozoa with progesterone (1 microM or bovine
follicular fluid (20%) induced the acrosome reaction from 12% (untreated
spermatozoa) to 25% (P < 0.001) and to 22% [corrected] (P < 0.01),
respectively. Incubation of both compounds (1 microM progesterone and 20%
follicular fluid) raised the percentage of acrosome-reacted spermatozoa to
30% (P < 0001). Our results demonstrate that cryopreserved semen can be
integrated into an in-vitro screening model for reproductive toxicology
testing. Pooled, cryopreserved bovine spermatozoa will thus permit
reproducible experiments for clinical and basic science purposes and may
also be applicable for the human system.
相似文献
67.
68.
Cloning, functional activities and in vivo tissue distribution of rat NKR-P1+ TCR alpha beta + cells
Knudsen E; Seierstad T; Vaage JT; Naper C; Benestad HB; Rolstad B; Maghazachi AA 《International immunology》1997,9(7):1043-1051
We have successfully cloned nine NKR-P1+ TCR alpha beta + cells from PVG
rat spleens, utilizing murine macrophage inflammatory protein-1 alpha
(MIP-1 alpha) and IL-2. These clones are either double negative (DN,
CD4-CD8-), which included clones 3.31, 3.71, 4.19, 4.59 and 4.65, or single
positive (SP, CD4+CD8-), which included clones 1.64, 3.8, 3.76 and 3.78. No
CD8+ clone was recovered. All nine clones are restricted in terms of their
expression of the V beta antigens, since they express V beta 8.2 but not V
beta 8.5, V beta 10 or V beta 16. These clones are agranular and they fall
to generate NK or LAK activity upon incubation with IL-2, IL-12 or their
combination. On the basis of their production of intracellular cytokines
they can be divided into three categories: (I) SP clones (1.64, 3.8, 3.76
and 3.78) do not produce IL-2 or IL-4, but produce IFN-gamma and IL-12, and
they vary in their production of IL-1, RANTES or tumor necrosis factor
(TNF)-alpha; (II) DN clones 4.59 and 4.65 produce IL-1 alpha and IFN-gamma
only, and fall to produce other cytokines; and (III) DN clones 3.31, 3.71
and 4.19 produce IL-1 alpha, IL-1 beta, IL-2, IL-12, IFN-gamma, RANTES and
TNF-alpha. From all the clones examined only DN clones 3.31 and to a lesser
degree 4.19 produce IL-4. In vivo tissue localization of clones 3.8, 3.31
and 4.59 shows that these cells distribute into the liver and bone marrow
24 h post i.v. administration. Their accumulation in the liver and bone
marrow along with their ability to secrete various cytokines suggest that
these cells may influence the generation, differentiation or apoptosis of
immune or hematopoietic cells.
相似文献
69.
70.
Stimulation of eosinophil production in vitro by eosinophilopoietin and spleen-cell-derived eosinophil growth-stimulating factor 总被引:4,自引:0,他引:4
Eosinophilopoietin (EPP) was previously characterized by the ability to stimulate eosinophil production in vivo, but these studies could not ascertain whether EPP had a direct effect on the bone marrow or acted indirectly by causing release of eosinophilopoietic activity by other tissues. The present studies demonstrate that EPP stimulates eosinophil growth in liquid culture of mouse bone marrow in vitro. The timing of stimulation by EPP in vivo and in vitro were parallel, with maximal eosinophil growth after 48 hr. Moreover, EPP appears similar to, and possible identical with, the eosinophil growth-stimulating substance (EO-GSF) released by antigenic stimulation of immune nonadherent spleen cells. Both EPP and EO-GSF are of low molecular weight, both produce stimulation of eosinophil growth with identical kinetics, and both produced similar dose-response curves in the liquid culture system. 相似文献