全文获取类型
收费全文 | 2374681篇 |
免费 | 195047篇 |
国内免费 | 4209篇 |
专业分类
耳鼻咽喉 | 34264篇 |
儿科学 | 72751篇 |
妇产科学 | 62931篇 |
基础医学 | 334871篇 |
口腔科学 | 67522篇 |
临床医学 | 215516篇 |
内科学 | 468584篇 |
皮肤病学 | 47931篇 |
神经病学 | 200775篇 |
特种医学 | 95957篇 |
外国民族医学 | 886篇 |
外科学 | 360425篇 |
综合类 | 56219篇 |
现状与发展 | 1篇 |
一般理论 | 977篇 |
预防医学 | 190602篇 |
眼科学 | 55462篇 |
药学 | 177521篇 |
4篇 | |
中国医学 | 4366篇 |
肿瘤学 | 126372篇 |
出版年
2018年 | 24204篇 |
2016年 | 20577篇 |
2015年 | 23278篇 |
2014年 | 33534篇 |
2013年 | 50831篇 |
2012年 | 68740篇 |
2011年 | 72277篇 |
2010年 | 42472篇 |
2009年 | 40864篇 |
2008年 | 68762篇 |
2007年 | 73093篇 |
2006年 | 73996篇 |
2005年 | 72033篇 |
2004年 | 69332篇 |
2003年 | 67010篇 |
2002年 | 66258篇 |
2001年 | 112450篇 |
2000年 | 116525篇 |
1999年 | 98333篇 |
1998年 | 27858篇 |
1997年 | 25522篇 |
1996年 | 25447篇 |
1995年 | 24609篇 |
1994年 | 23159篇 |
1993年 | 21552篇 |
1992年 | 79386篇 |
1991年 | 76393篇 |
1990年 | 73575篇 |
1989年 | 70841篇 |
1988年 | 65847篇 |
1987年 | 64803篇 |
1986年 | 61337篇 |
1985年 | 58400篇 |
1984年 | 44224篇 |
1983年 | 37657篇 |
1982年 | 22888篇 |
1981年 | 20333篇 |
1980年 | 19035篇 |
1979年 | 41300篇 |
1978年 | 28986篇 |
1977年 | 24348篇 |
1976年 | 22835篇 |
1975年 | 23965篇 |
1974年 | 29638篇 |
1973年 | 28043篇 |
1972年 | 26228篇 |
1971年 | 24156篇 |
1970年 | 22752篇 |
1969年 | 21089篇 |
1968年 | 19137篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
J. Duteil FA Rambert AM Pointeau P. Mangiameli and E. Assous 《Fundamental & clinical pharmacology》1991,5(8):695-708
The potential antidepressant effect of flerobuterol (dl-(fluoro-2 phenyl)-1 t-butylamino-2 ethanol), a new drug related to beta-adrenoceptor agonists, was evaluated and compared with imipramine and salbutamol using classical psychopharmacological tests in mice. Like imipramine and salbutamol, flerobuterol (0.5-32 mg kg-1, ip) fully prevented apomorphine (16 mg kg-1, sc)- and partly reversed reserpine- and oxotremorine-induced hypothermia. At higher doses (16-32 mg kg-1), flerobuterol enhanced the toxic effects of yohimbine. Unlike imipramine, flerobuterol and salbutamol did not reduce immobility duration in the behavioural despair test. Salbutamol and flerobuterol decreased locomotor activity. Flerobuterol did not induce mydriasis, did not prevent oxotremorine-induced tremors or salivary and lacrimal gland secretion and did not reduce reserpine-induced palpebral ptosis. Propranolol (8 mg kg-1, ip) but not alpha-methyl-paratyrosine (75 mg kg-1, ip) prevented the flerobuterol-induced antagonism of apomorphine-induced hypothermia. Our results suggest that flerobuterol demonstrates potential antidepressant activity, which could be related to beta-adrenoceptor activation in mice. 相似文献
992.
Lack of effect of the calcium antagonist isradipine on cyclosporine pharmacokinetics in renal transplant patients. 总被引:1,自引:0,他引:1
L Endresen S Bergan H Holdaas T Pran B Sinding-Larsen K J Berg 《Therapeutic drug monitoring》1991,13(6):490-495
Hypertension has emerged as a frequent side effect in transplant recipients on effective doses of cyclosporine (CsA). To control hypertension in renal transplant patients, calcium channel blockers have been used; some of these, however, have been shown to cause significant increases in CsA levels. These findings point out that possible interactions of each calcium antagonist with CsA deserve investigation. We performed an open, placebo-controlled study in 12 stable renal transplant recipients to determine whether short-term isradipine influences CsA pharmacokinetics. All patients had mild to moderate hypertension and received triple immunosuppressive therapy with CsA, azathioprine, and prednisolone. Throughout a 4-week period of isradipine treatment, blood CsA levels (specific and nonspecific monoclonal antibodies) remained stable. The mean trough specific level was 121 +/- 14 micrograms/L following placebo, compared to 120 +/- 14 micrograms/L during isradipine. Corresponding non-specific values were 465 +/- 68 and 474 +/- 63 micrograms/L. Also, values for Cmax, AUC, and t1/2 were not significantly changed following 4 weeks of isradipine. Mean arterial pressure was significantly reduced at the end of the study. This study implies that isradipine does not influence CsA metabolism. Further studies should be carried out to determine its long-term effects on CsA pharmacokinetics and renal function in transplanted patients. 相似文献
993.
When human divers and experimental animals are exposed to an increasing environmental pressure, they develop the high pressure neurological syndrome (HPNS) characterized by electroencephalographic changes and sleep and behavioral disturbances. In rats, behavioral disturbances essentially include hyperlocomotor activity (HLA), tremor and myoclonia. Moreover, HLA has recently been demonstrated to be linked to a pressure-induced striatal increase of dopamine (DA). In these experiments, it was proposed to investigate in rats, at the behavioral level, the role of DA receptors in the occurrence of the pressure-induced DA disturbances. DA receptor agonists were found to induce no significant changes in the development of HLA, tremor, and myoclonia. Alternatively, HLA was found to be dramatically antagonized by the use of DA receptor antagonists (SCH 23390, sulpiride, and haloperidol), while tremor and myoclonia only decreased in SCH 23390 experiments. 相似文献
994.
995.
A review of lacrimal drainage surgery 总被引:3,自引:0,他引:3
The advent of improved silicone intubation sets, increased understanding of lacrimal and nasal anatomy and physiology, and refinements in surgical instrumentation and technique have led to higher success rates in lacrimal surgery. Recent clinical studies, combined with new techniques in canalicular reconstruction, have helped identify which patients will benefit from surgical intervention and which techniques are indicated. Fortunately, this has greatly reduced the number of CDCRs necessary. 相似文献
996.
R Menningen M Günther N B?nninghoff C D Stahlknecht I Kubitza J Kusche 《Agents and actions》1986,18(1-2):38-40
In the operative treatment of appendicitis the so called negative appendectomy is an important issue because of its increased morbidity. From the hypothesis that the intestinal diamine oxidase activity is a suitable marker of mucosal integrity, the distribution pattern of the enzyme in appendices histologically classified as inflamed or not inflamed was studied. Histologically apparent inflammation of the appendix was connected with a significant reduction of diamine oxidase activity. The determination of this enzymic activity may be a simple and sensitive test for mucosal inflammation of the appendix even at a very early state. This could reduce the rate of negative appendectomies and influence thereby risk-cost-benefit calculations. 相似文献
997.
A López Bernal D J Hansell S Alexander A C Turnbull 《British journal of obstetrics and gynaecology》1987,94(11):1052-1058
The production of progesterone from pregnenolone, of cortisol from cortisone and of prostaglandin E (PGE) under basal and arachidonic acid-stimulated conditions was measured in cells dispersed from chorion and decidua. The cells were obtained after delivery from four groups of women: following spontaneous labour at term (38-42 weeks gestation), at elective caesarean section at term before the onset of labour, after induced labour at term, and after uncomplicated preterm (27-36 weeks) labour. Chorionic cells had a high progesterone output with relatively low cortisol and PGE production, whereas decidual cells had a high cortisol and PGE production rate. Free arachidonic acid stimulated PGE production in both decidual and chorionic cells. There were no significant differences in either steroid or PGE production among the four groups studied. These data suggest that steroid dehydrogenase activity in choriodecidual cells is not related to the mode of onset of labour and that the increased prostaglandin production in intrauterine tissues associated with parturition is due to enhanced availability of arachidonic acid. 相似文献
998.
999.
An extensive field survey allowed us to expand the geographical distribution of the scorpion Tityus perijanensis in the Perijá range, western Zulia State, Venezuela, including areas where adult cases of severe scorpionism have been reported. 16S ribosomal RNA (rRNA) gene sequencing, DL(50) determination, and native PAGE suggest low genetic and venom proteomic divergence across the distribution range. The results also indicate phylogenetic divergence between T. perijanensis and T. discrepans, the species prevalent in northcentral Venezuela. T. perijanensis venom lethality (0.91-0.94 mg/kg) is comparable to that of the Brazilian T. serrulatus and ranks highest among toxic Venezuelan Tityus studied so far. The data indicate that the Perijá range should be included amongst the endemic areas of scorpionism of Venezuela and Colombia. 相似文献
1000.
Birgit T Priest Kenneth M Blumenthal Jaime J Smith Vivien A Warren McHardy M Smith 《Toxicon》2007,49(2):194-201
The tarantula venom peptides ProTx-I and ProTx-II inhibit voltage-gated sodium channels by shifting their voltage dependence of activation to a more positive potential, thus acting by a mechanism similar to that of potassium channel gating modifiers such as hanatoxin and VSTX1. ProTx-I and ProTx-II inhibit all sodium channel (Nav1) subtypes tested with similar potency and represent the first potent peptidyl inhibitors of TTX-resistant sodium channels. Like gating modifiers of potassium channels, ProTx-I and ProTx-II conform to the inhibitory cystine knot motif, and ProTx-II was demonstrated to bind to sodium channels in the closed state. Both toxins have been synthesized chemically, and ProTx-II, produced by recombinant means, has been used to map the interaction surface of the peptide with the Nav1.5 channel. In comparison, beta-scorpion toxins activate sodium channels by shifting the voltage dependence of activation to more negative potentials, and together these peptides represent valuable tools for exploring the gating mechanism of sodium channels. 相似文献