全文获取类型
收费全文 | 2701805篇 |
免费 | 195175篇 |
国内免费 | 7265篇 |
专业分类
耳鼻咽喉 | 35302篇 |
儿科学 | 88644篇 |
妇产科学 | 73521篇 |
基础医学 | 387988篇 |
口腔科学 | 77092篇 |
临床医学 | 252009篇 |
内科学 | 521314篇 |
皮肤病学 | 58261篇 |
神经病学 | 215794篇 |
特种医学 | 100027篇 |
外国民族医学 | 592篇 |
外科学 | 394875篇 |
综合类 | 61715篇 |
现状与发展 | 5篇 |
一般理论 | 949篇 |
预防医学 | 214524篇 |
眼科学 | 62808篇 |
药学 | 198432篇 |
12篇 | |
中国医学 | 6869篇 |
肿瘤学 | 153512篇 |
出版年
2021年 | 21036篇 |
2019年 | 22047篇 |
2018年 | 31653篇 |
2017年 | 23948篇 |
2016年 | 26263篇 |
2015年 | 29937篇 |
2014年 | 41526篇 |
2013年 | 62299篇 |
2012年 | 85938篇 |
2011年 | 90904篇 |
2010年 | 53598篇 |
2009年 | 49767篇 |
2008年 | 83861篇 |
2007年 | 89037篇 |
2006年 | 89664篇 |
2005年 | 86010篇 |
2004年 | 82491篇 |
2003年 | 78466篇 |
2002年 | 76021篇 |
2001年 | 131308篇 |
2000年 | 134687篇 |
1999年 | 112234篇 |
1998年 | 30717篇 |
1997年 | 27118篇 |
1996年 | 27044篇 |
1995年 | 25883篇 |
1994年 | 23967篇 |
1993年 | 22272篇 |
1992年 | 86864篇 |
1991年 | 84289篇 |
1990年 | 81212篇 |
1989年 | 77759篇 |
1988年 | 71373篇 |
1987年 | 69755篇 |
1986年 | 66112篇 |
1985年 | 62910篇 |
1984年 | 46758篇 |
1983年 | 39828篇 |
1982年 | 23060篇 |
1979年 | 41842篇 |
1978年 | 29371篇 |
1977年 | 24568篇 |
1976年 | 23349篇 |
1975年 | 24319篇 |
1974年 | 29596篇 |
1973年 | 28716篇 |
1972年 | 26647篇 |
1971年 | 24715篇 |
1970年 | 22985篇 |
1969年 | 21285篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Biological fixation of porous-coated implants 总被引:1,自引:0,他引:1
R J Haddad S D Cook K A Thomas 《The Journal of bone and joint surgery. American volume》1987,69(9):1459-1466
992.
Single course versus maintenance bacillus Calmette-Guerin therapy for superficial bladder tumors: a prospective, randomized trial 总被引:1,自引:0,他引:1
M A Hudson T L Ratliff D P Gillen E O Haaff S M Dresner W J Catalona 《The Journal of urology》1987,138(2):295-298
A total of 42 patients with recurrent superficial bladder tumors or carcinoma in situ entered a prospective, randomized trial to compare the efficacy of bacillus Calmette-Guerin therapy with and without quarterly maintenance instillations of bacillus Calmette-Guerin. Maintenance therapy did not reduce further bladder tumor recurrence rates or the interval to recurrence in patients who responded to the initial course of therapy. However, prolongation of toxicity was observed with maintenance bacillus Calmette-Guerin therapy. 相似文献
993.
Kojic amine [2-(aminomethyl)-5-hydroxy-4H-pyran-4-one], an analogue of gamma-aminobutyric acid (GABA), produced dose-related, but short-lived, antinociceptive activity in the 48 degrees C [ED50 = 9.2 (8.2-10.3) mg/kg i.p.] and 55 degrees C [ED50 = 13.8 (12.2-15.7) mg/kg i.p.] hot-plate tests in the mouse. The antinociceptive activity of kojic amine at 48 degrees C was found to be insensitive to bicuculline (1.0 mg/kg i.p.) and picrotoxin (0.5 mg/kg i.p.). At this temperature, antinociception was distinctly separate from the impairment of motor function (measured by a rotorod assay) and was not significantly affected by prior treatment with the cholinergic antagonist, atropine sulfate (10.0 mg/kg i.p.). However, at 55 degrees C, the antinociceptive effect of a large dose (20 mg/kg i.p.) of kojic amine was significantly attenuated by similar pretreatment with atropine sulfate, but not by the peripheral cholinergic antagonist, atropine methylnitrate (10.0 mg/kg i.p.). Kojic amine exhibited no significant interaction with haloperidol (0.5 mg/kg i.p.) at this temperature. In animals made tolerant to morphine, THIP or baclofen, there was analgesic cross-tolerance between kojic amine, morphine and baclofen but not between kojic amine and THIP. It is suggested that kojic amine-induced antinociception is similar to that produced by both THIP and baclofen. Thus, kojic amine represents a unique tool with which to study GABA-ergic antinociceptive processes. 相似文献
994.
Computed tomographic (CT) scans of the brain in a child with Smith-Lemli-Opitz syndrome revealed enlargement of the ventricular system, hypoplasia of the cerebellum, and abnormal thickening of the gray matter, consistent with pachygyria. These findings have been previously noted in autopsies performed on patients with this disorder. We conclude that CT scanning is a valuable tool in the evaluation of children suspected of having the Smith-Lemli-Opitz syndrome. 相似文献
995.
996.
997.
Obesity and beta-blockers: influence of body fat on their kinetics and cardiovascular effects 总被引:2,自引:0,他引:2
F Galletti M L Fasano L A Ferrara A Groppi M Montagna M Mancini 《Journal of clinical pharmacology》1989,29(3):212-216
Beta-blockers are among the most widely used antihypertensive drugs. They differ from each other in regard to several factors such as: beta-agonist activity, beta 1-selectivity and solubility. Aim of this work was to evaluate the influence of obesity on the kinetics and the antihypertensive effect of two Beta-blockers with different solubility such as: the water-soluble, atenolol and the liposoluble, metoprolol. The study was carried out according to an open randomized cross-over design. Eight obese hypertensive patients, after a two week washout period, were randomly allocated to a four week treatment. After a two week intermediate washout period, each patient switched to the other treatment for an additional four week period. On the first and the last day of each treatment the subjects were hospitalized to collect blood samples for the assay of the two drugs and to measure cardiovascular parameters. Obesity does not exert any effect on the kinetics of the water-soluble beta-blocker, atenolol, while markedly interferes with that of the liposoluble, without any apparent influence on its anti-hypertensive effect. These findings extend to obese hypertensives the concept that the plasma concentrations of beta-blocking agents are not reliable predictors of their therapeutic effect. 相似文献
998.
Prenatal, intrapartum and postnatal factors were investigated in less than 32 gestational age preterm infants known to have periventricular haemorrhage or periventricular leukomalacia. The diagnoses were established on cranial ultrasonography and/or autopsy. Factors associated with periventricular haemorrhage were: postnatal severe hypercapnia, acidosis and hypoxia. In the periventricular leukomalacia group the incidence of antepartum and intrapartum hypoxia and/or ischaemia (antepartum haemorrhage) were significantly higher than in the control group. 相似文献
999.
Retained pacemaker leads 总被引:2,自引:0,他引:2
S Furman M Behrens C Andrews P Klementowicz 《The Journal of thoracic and cardiovascular surgery》1987,94(5):770-772
Increasingly, functionless pacemaker leads are being abandoned in place because they cannot be safely removed. One hundred eighty-nine intact or partially removed pacemaker leads were abandoned in situ in 152 patients between Jan. 1, 1965, and Dec. 31, 1985. The leads, sometimes several leads in a single patient, were deemed uninfected at the time of abandonment in 137 patients and contaminated with Staphylococcus epidermidis in 15 patients. All of the contaminated leads have remained clinically uninfected during follow-up. One clean lead became infected early after implantation and the patient died after an open cardiac operation to remove that lead and an adjacent abandoned lead that was adherent to the subclavian vein. No other patient has had a late complication during follow-up to 256 months (mean 47.6). Properly managed abandonment of an uninfected lead can carry a very low complication rate. 相似文献
1000.
Immunosuppressive activities of the newly discovered FK506, isolated from Streptomyces tsukubaensis, were examined by using cardiac allotransplantation in the rat, and the mechanisms underlying induction and maintenance of FK506-induced long-term allograft survival were studied. Male rats of WKA (RT1k) and F344 (RT1lvl) strains were used as recipients and donors, respectively, and those of BN (RT1n) strain were used as third-party donors. Treatment with FK506, beginning from the day of allografting for 14, 10, or as few as 4 days, prolonged allograft survival significantly across the major histocompatibility barrier. The minimum doses for prolonging graft survival were 0.1 mg/kg/day by intramuscular treatment and 1.0 mg/kg/day by oral treatment. Treatment with FK506 at a dose of 0.32 mg/kg/day from day 4 until day 10 resulted in all the grafts surviving indefinitely and from days 5 to 10, half the grafts survived indefinitely, suggesting that the agent inhibited ongoing rejection. On the other hand, cyclosporine treatment at a dose of 20 mg/kg/day from day 2 did not prolong graft survival time statistically significantly. Induction of prolonged graft survival was not obtained by pretreatment of the prospective donor or recipient; prolonging effects were observed only when the agent was administered after allografting. Thus, the primary effect of the agent is exerted on responder lymphocytes reacting to the donor antigens in the induction phase of long-term graft acceptance. The mechanisms underlying the maintenance of long-term grafts were analyzed by testing the capacity of lymphocytes or serum of long-term graft-bearing rats to inhibit graft rejection in irradiated grafted hosts. Transfer of 2 x 10(8) lymphocytes from FK506-induced long-term F344 graft-bearing WKA rats resulted in indefinite survival of F344 heart allografts, but it did not prolong survival of third-party BN hearts. Transfer of 2.5 ml serum from long-term graft-bearing rats also prolonged graft survival of F344 hearts, but not BN hearts. These results suggest that donor strain-specific suppressor cells and humoral factor(s) are induced by treatment with FK506 in the presence of allografts, and that they play at least partial roles in the maintenance of long-term allograft acceptance. 相似文献