全文获取类型
收费全文 | 141691篇 |
免费 | 8649篇 |
国内免费 | 959篇 |
专业分类
耳鼻咽喉 | 1679篇 |
儿科学 | 3977篇 |
妇产科学 | 3445篇 |
基础医学 | 19328篇 |
口腔科学 | 3507篇 |
临床医学 | 12809篇 |
内科学 | 30835篇 |
皮肤病学 | 2731篇 |
神经病学 | 13391篇 |
特种医学 | 5316篇 |
外国民族医学 | 23篇 |
外科学 | 19156篇 |
综合类 | 1962篇 |
一般理论 | 89篇 |
预防医学 | 8856篇 |
眼科学 | 2263篇 |
药学 | 10855篇 |
4篇 | |
中国医学 | 566篇 |
肿瘤学 | 10507篇 |
出版年
2023年 | 690篇 |
2022年 | 1542篇 |
2021年 | 2783篇 |
2020年 | 1811篇 |
2019年 | 2486篇 |
2018年 | 3083篇 |
2017年 | 2499篇 |
2016年 | 2749篇 |
2015年 | 3049篇 |
2014年 | 4047篇 |
2013年 | 5943篇 |
2012年 | 8323篇 |
2011年 | 8690篇 |
2010年 | 5433篇 |
2009年 | 4843篇 |
2008年 | 7454篇 |
2007年 | 7950篇 |
2006年 | 7353篇 |
2005年 | 7212篇 |
2004年 | 7325篇 |
2003年 | 6996篇 |
2002年 | 6815篇 |
2001年 | 4101篇 |
2000年 | 3990篇 |
1999年 | 3415篇 |
1998年 | 1653篇 |
1997年 | 1317篇 |
1996年 | 1194篇 |
1995年 | 1105篇 |
1994年 | 969篇 |
1993年 | 943篇 |
1992年 | 1995篇 |
1991年 | 1974篇 |
1990年 | 1691篇 |
1989年 | 1648篇 |
1988年 | 1504篇 |
1987年 | 1341篇 |
1986年 | 1335篇 |
1985年 | 1234篇 |
1984年 | 932篇 |
1983年 | 852篇 |
1982年 | 630篇 |
1981年 | 534篇 |
1980年 | 486篇 |
1979年 | 674篇 |
1978年 | 533篇 |
1977年 | 497篇 |
1975年 | 532篇 |
1974年 | 559篇 |
1973年 | 526篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
I Patty S Benedek G Deák T Jávor P Kenéz F Morón L Nagy L Simon F Tárnok G Mózsik 《International journal of tissue reactions》1983,5(3):301-307
The effects of vitamin A were studied on the basal and maximal gastric secretory responses of 12 patients; and on healing in 60 patients with chronic gastric ulcer. The effect of vitamin A on ulcer healing was evaluated by a multiclinical, multicentre, randomized, prospective study in which the patients were divided into three groups. In group A the patients were treated with antacids only; in group B the patients were given antacids plus vitamin A (in doses of 3 X 50.000 U orally); and in group C the patients received antacids, vitamin A plus cyproheptadine (in doses of 3 X 4 mg orally). The treatment lasted four weeks. At the beginning and the end of treatment endoscopies were performed and ulcer sizes were measured planimetrically. Various other parameters such as ulcer index, antacid consumption and laboratory parameters were also evaluated during the four-week treatment. It was observed that: (i) vitamin A (given in doses of 100.000 U i.m.) decreased neither basal nor maximal gastric secretory responses; (ii) the number of patients with completely healed gastric ulcer was significantly higher (P less than 0.05) in groups B and C than in group A; (iii) the extent of ulcer reduction was significantly higher (P less than 0.01) in groups B and C than in group A; (iv) no significant changes were observed in ulcer index and antacid consumption during the four-week treatment in the different groups of patients; (v) the reduction of ulcer size was significantly greater (P less than 0.01) in the group treated with antacids plus vitamin A than in the group treated with antacids only, at two weeks of treatment.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
992.
Kloek J. Van Ark I. De Clerck F. Bloksma N. Nijkamp F. P. Folkerts G. 《Inflammation research》2003,52(3):126-131
OBJECTIVE AND DESIGN: Since oxidative stress contributes to the pathogenesis of asthma, this study addressed the question whether supplementing the endogenous antioxidant, glutathione (GSH), would alleviate features of allergic asthma in the mouse. MATERIAL AND METHODS: Ovalbumin-sensitized mice received aerosols of the GSH-donors, glutathione-ethyl ester (GSEt) or N-acetylcysteine, before or during respiratory allergen challenges, or during methacholine challenges given one day after the last allergen challenge. Lung GSH levels were measured shortly after allergen or methacholine challenge. In addition, the effect of GSH supplements on airway hyperresponsiveness and inflammatory cell numbers in the airway lumen was assessed. RESULTS: GSEt decreased allergen-induced airway hyperresponsiveness when given in combination with methacholine. However, when given before or during allergen challenge, both GSH-donors failed to decrease the methacholine-induced airway contractility, change cell numbers in the airway lumen, or increase lung GSH levels. In addition, allergen challenges of sensitized mice did not decrease lung GSH levels. CONCLUSION: In contrast to guinea pigs and humans, allergen challenges in mice does not lead to acute oxidative stress. 相似文献
993.
The effects of postnatal protein malnutrition on juvenile social behaviors were investigated in male and female Wistar rats. During the lactation period (21 days), each litter (six male and two female pups) was provided with 16% (control) or 6% (low protein) casein diets. At weaning, the control group (W) continued to receive the 16% protein diet and the malnourished group was divided into two groups: one continuing to receive a 6% protein diet (malnourished group - M) and the other shifted to a 16% protein diet (previously malnourished group - PM). These conditions lasted until 38 days of age when the behavioral tests ended. To assess social interaction, pairs of rats of the same nutritional condition and same gender were placed in a familiar arena for 3 consecutive days. Playful social behavior (pin), nonplayful social behavior (anogenital sniff, walk-over, side-mount and allogroom) and nonsocial behavior (rear) were recorded in three 10-min sessions. Postnatal protein malnutrition significantly decreased playful social behavior, nonsocial behavior (rear) and nonplayful social behaviors such as side-mount and walk-over. Anogenital sniff and allogroom were increased by early malnutrition. Nutritional rehabilitation from weaning reversed the changes produced by protein malnutrition in nonplayful (side-mount, walk-over, anogenital sniff and allogroom) and nonsocial behaviors (rear) but increased playful social behavior (pin). Gender effects were observed only on side-mount (higher incidence in males) and walk-over (higher incidence in females) indicating that playful behavior and nonsocial behavior were not affected by sex. The present results suggest that behavioral differences described in adulthood may result from changes in social behaviors of juvenile rats induced by early protein malnutrition. 相似文献
994.
Mangweth B Kemmler G Ebner C De Col C Kinzl J Biebl W Vingerhoets A 《Psychotherapy and psychosomatics》1999,68(6):319-324
BACKGROUND: The aim of the study was to examine the proneness, the functions and triggering situations of weeping in anorexic and bulimic women. METHODS: Participants were 36 anorexic and 31 bulimic female patients and 56 age-matched female controls. All women completed the Questionnaire on Adult Crying. We limited our study to results on 'crying proneness', 'functions of crying' and 'determining factors of crying'. RESULTS: Bulimic patients reported to have cried significantly more often in the last 4 weeks, to be more likely to cry in situations of distress and to have used weeping significantly more often as a manipulative behavior than control women. Anorexic patients rated their tendency to cry significantly lower and experienced weeping as significantly more negative than controls. CONCLUSIONS: Compared to control women, anorexic patients associated weeping with negative feelings as opposed to bulimic patients who appeared to use weeping on an intentional basis. These deviations from control women seem to mirror the introvert character of anorexic patients and the extrovert impulsive personality of patients with bulimia nervosa, respectively. 相似文献
995.
Female reproductive health in two lamp factories: effects of exposure to inorganic mercury vapour and stress factors 总被引:1,自引:0,他引:1
F De Rosis S P Anastasio L Selvaggi A Beltrame G Moriani 《British journal of industrial medicine》1985,42(7):488-494
To evaluate the possible influence of mercury vapour on female reproduction, 153 women working in a mercury vapour lamp factory have been compared with 193 women employed in another factory of the same company, where mercury was not used. Both groups of subjects were exposed to stress factors (noise, rhythms of production, and shift work). The production process has been analysed by inspection of the plants and by collective discussions with "homogeneous groups" of workers; a retrospective inquiry into work history and reproductive health events has been subsequently performed by an individual interview. Women exposed to mercury vapour currently not exceeding the time weighted average air concentration of 0.01 mg/m3 declared higher prevalence and incidence rates of menstrual disorders, primary subfecundity, and adverse pregnancy outcome; however, the progression of these problems with the level of exposure to mercury inside the same factory was not always clear. The results of this study neither prove nor exclude the possibility that occupational exposure to this concentration of mercury has a negative effect on female reproduction. 相似文献
996.
P. E. R. Rhemrev W. A. A. Van Os J. Kleinhout C. C. A. De Nooyer 《Advances in Contraception》1985,1(1):31-36
A comparative study was made of three differently loaded Multiload intrauterine contraceptive devices. The IUDs were used by 450 women for 3 years unless the device was removed earlier. The reasons for IUD removal (pregnancy, bleeding and/or pain, and other) were recorded, and the data analyzed after 1 year and after 3 years using the log-rank method. No statistically significant differences could be found among the three devices either in rate of pregnancy nor IUD removal for any reason.
Resumen Se hizo un estudio comparativo de tres anticonceptivos intrauterinos Multiload con tres cargas diferentes. Durante tres años, 450 mujeres usaron los DIU a menos que el dispositivo hubiera sido quitado antes. Las razones para la remoción de los DIU (embarazo, sangrado y/o dolor y otras) fueron registradas y los datos se analizaron después de l año y de 3 años, usando el método log-rank. No se pudo encontrar ninguna diferencia estadísticamente significativa entre los tres dispositivos sea en la tasa de embarazos o en la remoción de los DIU por cualquier razón.
Resumé On a conduit une étude pour comparer 3 DIU multichargés, de charge différente. Ces DIU ont été utilisés par 450 femmes pendant 3 ans, sauf retrait plus précoce. On a relevé les motifs de retrait du DIU (grossesse, hémorragie et/ou douleurs et autres motifs) et analysé les données au bout de 1 an et de 3 ans, par la méthode des rangs logarithmiques. Aucune différence statistiquement significative n'a été constatée entre les 3 DIU; ni sur le plan du taux de grossesse ni sur celui du taux de retrait, pour un motif quelconque.相似文献
997.
S. Bondesen MD H. Christensen MD K. Lindorff-Larsen MD Dr. O. B. Schaffalitzky De Muckadell MD 《Digestive diseases and sciences》1985,30(5):440-444
The effect of exogenous bile salts on plasma concentrations of secretin was studied by infusion of chenodeoxycholate, cholate, glycocholate, and taurocholate into the duodenum of normal subjects. The effect of endogenous bile on plasma secretin was studied by ingestion of a liquid test meal, by reinfusion of postprandial duodenal aspirates with known contents of bile salts, and by stimulation of gallbladder contraction by cholecystokinin. Each experiment was performed in groups of seven subjects. The relative secretin-releasing potencies of glycocholate, cholate, taurocholate and chenodeoxycholate (2.25 mmol) were 1.01.31.93.2. Hydrochloric acid (0.5 mmol) was, on a molar basis, approximately ten times more potent than sodium cholate. The effect of taurocholate was diminished when a liquid meal was used as vehicle instead of saline. Endogenous bile did, in no circumstance, elicit release of secretin. It is concluded that although bile salts have the ability to stimulate secretin release, endogenous secretin release is of minor, if any, importance for secretin release when physiological conditions are approached.This study was supported by grants from the Danish Hospital Foundation for Medical Research, Region of Copenhagen, The Faroe Islands and Greenland (J.nr. 78/45 and 79/48) and Borgen Legatet. 相似文献
998.
P. Van de Perre N. Clumeck M. Steens G. Zissis M. Carapl R. Lagasse S. De Wit T. Lafontaine P. De Mol J. P. Butzler 《European journal of epidemiology》1987,3(1):14-18
A seroepidemiological study was performed on HTLV-III, T. pallidum, C. trachomatis and Hepatitis B virus (HBV), in Butare, Rwanda, among 33 female prostitutes, 25 male customers of prostitutes, and 60 male and female controls. As compared with female controls the prostitutes had a higher prevalence of antibodies to HTLV-III (29/33 versus 4/33, p<0.001), T. pallidunz (TPHA: 27/33 versus 6/33, p<0.001; RPR: 19/33 versus 233, p<0.001; FTA-Abs: 27/33 versus 5/33, p<0:001) and C. trachomatis (IgG IF: 31/33 versus 13/33, p<0.001). HBV serological markers were more often detected in the prostitutes than in the female controls (31/33 versus 18/33, p<0.001) although HBs antigen carriage rate was similar in both groups. As compared with male controls, the male customers of prostitutes had more frequently detectable antibodies to HTLV-III (7/25 versus 2/27, p = 0.05), and a positive RPR (10/25 versus 1/27, p<0.01). Among the 118 individuals studied, odds ratios and trend analysis disclosed a significant association between HTLV-III seropositivity and a positive TPHA, RPR, FTA-Abs, Chlamvdia IgG IF test and serological markers to HBV. No association was found between HTLV-III seropositivity and IIBs Ag carriage. This study suggests that HTLV-III has to be considered as an infectious agent transmitted among promiscuous Central African heterosexuals by sexual contact and/or parenteral contact with unsterile needles used for STD treatments. 相似文献
999.
Patients' use of a newly prescribed inhaler was evaluated on the basis of pulmonary function test (PFT) results and the number of steps of an 11-step inhaler sequence that were completed correctly. Adult male outpatients with mild to moderate chronic obstructive pulmonary disease were assigned to a counseled (n = 10) or noncounseled (n = 9) group. Patient characteristics were similar in both groups. The counseled group was instructed by a pharmacist on the correct use of the inhaler; the noncounseled group was not. Counseled patients had a significantly higher mean percentage change in forced expiratory volume in one second (FEV1) after inhaler use than did the noncounseled group. The mean number of steps missed was significantly greater for the noncounseled group, and there was a significant negative correlation between the number of steps missed and the percentage change in FEV1. Evaluation of the 11-step inhaler sequence identified three steps ("shake the inhaler," "use one puff at a time," and "shake between puffs") that correlated with PFT results and appeared to contribute to improved bronchodilation. Of the five patients who achieved adequate response, only four (all in the counseled group) performed these steps correctly. Instruction with demonstration and practice resulted in better patient understanding and performance of the correct steps for inhaler use, with improved bronchodilation as measured by PFTs. 相似文献
1000.
Godefridus J. Peters Cees J. van Groeningen Emile Laurensse Ineke Kraal Albert Leyva Jan Lankelma Herbert M. Pinedo 《Pharmaceutical research》1987,4(2):113-119
The effect of high-dose uridine on body temperatures of rabbits and man has been studied in relation to plasma concentrations of uridine and its catabolite uracil. Uridine induced fever in both rabbits and man. High-dose cytidine had no influence on body temperature in rabbits. Plasma concentrations of uridine were between 1 and 1.5 mM at 30 min after an iv bolus injection of 400 mg uridine/kg in rabbits and reached peak levels of 2 mM after a 1-hr infusion of 12 g uridine/m2 in man. The plasma concentration of cytidine in rabbits was about 0.5 mM and that of uridine was 0.30 mM at 30 min after an iv bolus injection of 400 mg cytidine/kg. The mean residence time for uridine in patients and rabbits varied between 80 and 195 min. The area under the plasma concentration–time curve (AUC) for uridine in rabbits was 2.0 mmol · hr/liter, and that for cytidine was 0.6 mmol · hr/liter. A large AUC for uridine indicates a prolonged exposure of tissues to uridine, which might lead to extensive formation of degradation products. The administration of some of these catabolites, dihydrouracil (at 20–40 mg/kg), carbamyl--alanine (at 60 mg/kg), and -alanine (at 300–400 mg/kg), resulted in a significant increase in body temperature. It is concluded that the change in body temperature associated with uridine administration was not due to bacterial pyrogens but that one of the degradation products might be involved in thermoregulation. 相似文献