全文获取类型
收费全文 | 10754篇 |
免费 | 712篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 281篇 |
妇产科学 | 194篇 |
基础医学 | 1533篇 |
口腔科学 | 210篇 |
临床医学 | 1026篇 |
内科学 | 2422篇 |
皮肤病学 | 202篇 |
神经病学 | 852篇 |
特种医学 | 411篇 |
外科学 | 1643篇 |
综合类 | 92篇 |
一般理论 | 4篇 |
预防医学 | 843篇 |
眼科学 | 333篇 |
药学 | 671篇 |
中国医学 | 16篇 |
肿瘤学 | 716篇 |
出版年
2023年 | 35篇 |
2022年 | 170篇 |
2021年 | 283篇 |
2020年 | 123篇 |
2019年 | 218篇 |
2018年 | 294篇 |
2017年 | 186篇 |
2016年 | 198篇 |
2015年 | 232篇 |
2014年 | 302篇 |
2013年 | 482篇 |
2012年 | 715篇 |
2011年 | 753篇 |
2010年 | 432篇 |
2009年 | 364篇 |
2008年 | 654篇 |
2007年 | 697篇 |
2006年 | 627篇 |
2005年 | 699篇 |
2004年 | 623篇 |
2003年 | 569篇 |
2002年 | 581篇 |
2001年 | 121篇 |
2000年 | 134篇 |
1999年 | 144篇 |
1998年 | 138篇 |
1997年 | 122篇 |
1996年 | 88篇 |
1995年 | 101篇 |
1994年 | 83篇 |
1993年 | 91篇 |
1992年 | 93篇 |
1991年 | 108篇 |
1990年 | 85篇 |
1989年 | 86篇 |
1988年 | 73篇 |
1987年 | 68篇 |
1986年 | 51篇 |
1985年 | 52篇 |
1984年 | 63篇 |
1983年 | 54篇 |
1982年 | 55篇 |
1981年 | 47篇 |
1980年 | 45篇 |
1979年 | 29篇 |
1978年 | 29篇 |
1977年 | 30篇 |
1976年 | 19篇 |
1974年 | 19篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
It has been suggested that albumin reduces quinidine capillary permeability (PS) in the single-pass perfused heart preparation by reducing paracellular transport of quinidine ions. Using this preparation, we examined the effect of albumin (0.1 per cent) on quinidine PS at perfusate pHs of 7.1 and 7.9 during uptake of quinidine (19 µM) and also during washout of the drug using a randomized design. Quinidine PS was approximately 16 ml/min/g heart at pH 7.9 and was not altered by the presence of albumin in perfusate. At pH 7.1, in the absence of albumin, quinidine PS was also 16 ml/min/g, but in the presence of albumin (0.1 per cent) PS was reduced significantly to approximately 5 ml/min/g (P < 0.001). In the absence of albumin PS was the same at pH 7.1 and 7.9 in spite of a greater degree of ionisation of quinidine at pH 7.1. This suggests that there is significant uptake of ionised quinidine at pH 7.1. The greater effect of albumin on PS at pH 7.1 supports the hypothesis that albumin reduces paracellular transport of quinidine ions. 相似文献
92.
F. Labrot J. F. Narbonne P. Ville M. Saint Denis D. Ribera 《Archives of environmental contamination and toxicology》1999,36(2):167-178
The general objective of our work was to propose new reference material for chemical toxicity testing and new sentinel organisms
for environmental quality survey programs (freshwater or soils). We also wanted to provide basic toxicological data on the
environmental effects of uranium. Thus, we conducted a comparative study to establish the acute toxicity and toxicokinetics
of lead (Pb) and uranium (U) to the bivalve mollusc Corbicula fluminea and the terrestrial annelid Eisenia fetida andrei and to compare these findings with those of the well-known teleost fish Brachydanio rerio. We then measured the concentration of these metals in various tissues of the clam and the worm after two periods of exposure
(4 and 11 days) to identify the affinities of these tissues for Pb and U. Our results have shown that Pb and U are very toxic
to Eisenia and relatively nontoxic to Corbicula. By comparison, Pb was relatively nontoxic and U appeared to be very toxic to the fish. The toxicokinetic studies indicated
that the three species are able to accumulate Pb and U, the rate and level of accumulation depending both on the species and
the metal. We also found that fish and clams depurate the two metals. Data collected for the worm were conflicting: Pb was
not depurated whereas tissue concentrations of U declined after the eighth day of exposure. Our study has also shown that
the tissue distribution of Pb in the mollusc and in the earthworm differs significantly from that of U, both after 4 and 11
days exposure. In conclusion, these three species showed potential as bioindicators of environmental contamination by metals.
Indeed, they could be used in conjunction to test different compartments of an ecosystem: worms for soils, fish for the water
column, and clams for the water/sediment interface.
Received: 30 October 1996/Accepted: 1 September 1998 相似文献
93.
Pretreatment of rats with the extract of Ginkgo biloba termed EGb761 reduced the behavioral sensitization induced by successive
-amphetamine administrations (0.5 mg/kg) as estimated by increasing values of locomotor activity. EGb761 pretreatment also prevented the reduced density of [3H]dexamethasone binding sites in the dentate gyrus and the CA1 hippocampal regions of
-amphetamine treated animals. These observations suggest that EGb761, by reducing glucocorticoid levels, could modulate the activity of the neuronal systems involved in the expression of the behavioral sensitization. 相似文献
94.
95.
After noting a striking difference in the dosing practices of two treating psychiatrists, each responsible for the operation of a clozapine unit in a state psychiatric hospital, the authors conducted a retrospective chart review to assess the clinical efficacy of low dose
mg. per day) versus high dose (
mg. per day) clozapine treatment for a cohort of 31 inpatients. Levels of psychopathology, behavior, and social functioning were assessed six months pre and during clozapine treatment for 16 patients who received low dose clozapine treatment and 15 patients who received high dose clozapine treatment. Patients on both units demonstrated significant reductions in their levels of psychopathology, improved social functioning and improvement in their behavior following six months clozapine treatment. This naturalistic study suggests that the use of low dose clozapine provides effective treatment for chronic, severely treatment resistant inpatients with schizophrenia or schizo-affective illness, at the same time reducing the potential for significant side effects. 相似文献
96.
Sally Betz Corradin Jacques Mauël Susanne Denis Donini Emilia Quattrocchi Paola Ricciardi-Castagnoli 《Glia》1993,7(3):255-262
Nitric oxide (NO) is a short-lived diffusable molecule now believed to participate in multiple physiologic functions in the CNS including neurotransmission and the maintenance of vascular tone. Previously, we reported that cell lines obtained by retroviral immortalization of tissue macrophages (M?;) could be induced to synthesize nitrite (NO), a stable end product of the NO synthetic pathway. We have further characterized the induction and activity of this pathway in a panel of seven microglial clones derived from primary embryonic mouse brain cultures. Like M?;, these clones were found to release high levels of NO-2 in response to recombinant interferon-γ (rIFN-γ) as a priming signal together with either bacterial lipopolysaccharide (LPS) or exogenous recombinant tumor necrosis factor-α (rTNF-α). As previously demonstrated for M?;, phagocytosis of zymosan particles during induction of enzyme activity enhanced subsequent NO production, which is of interest in light of the postulated phagocytic role of microglia within the CNS. Biochemical characterization of enzyme activity in intact microglial clones and in isolated cytosolic fractions indicates that the microglial NO synthase present in these murine cell clones represents the M?;-like isotype. These findings suggest that microglial cells could represent a major source of NO within the CNS. 相似文献
97.
98.
Denis JL Champagne F Contandriopoulos AP Cazale L 《The International journal of health planning and management》1992,7(2):79-101
This article reports the results of a case study, spanning a period of 10 years, of the merger of two hospitals in a publicly-funded health system. A political economy model was used to analyse the determinants of the merger. Results show that external political economy factors, mainly pressure from the state to rationalize health services and the organization's needs to acquire critical resources, significantly contributed to the merger decision. At the internal political economy level, groups and individual strategies also played a determinant role. Our study suggests that merger in the public sector may not necessarily result from efficiency motives. 相似文献
99.
Summary A method is described for the growth of calcium oxalate dihydrate in normal urine. Soluble chlorophyllin, at a concentration of 20 g/ml inhibited the crystallisation and the growth kinetics of the dihydrate crystals. The inhibitory capacity of chlorophyllin was compared with previous results. Data obtained suggest that the food and drug colourant chlorophyllin might be useful in the treatment of calcium oxalate stone disease. 相似文献
100.