全文获取类型
收费全文 | 949026篇 |
免费 | 79174篇 |
国内免费 | 9040篇 |
专业分类
耳鼻咽喉 | 13442篇 |
儿科学 | 25431篇 |
妇产科学 | 26039篇 |
基础医学 | 134412篇 |
口腔科学 | 27033篇 |
临床医学 | 88050篇 |
内科学 | 177171篇 |
皮肤病学 | 17649篇 |
神经病学 | 75176篇 |
特种医学 | 38290篇 |
外国民族医学 | 227篇 |
外科学 | 144175篇 |
综合类 | 39780篇 |
现状与发展 | 24篇 |
一般理论 | 276篇 |
预防医学 | 72552篇 |
眼科学 | 23426篇 |
药学 | 73682篇 |
102篇 | |
中国医学 | 7372篇 |
肿瘤学 | 52931篇 |
出版年
2021年 | 10118篇 |
2019年 | 8377篇 |
2018年 | 10673篇 |
2017年 | 8596篇 |
2016年 | 9295篇 |
2015年 | 11932篇 |
2014年 | 16281篇 |
2013年 | 21126篇 |
2012年 | 29106篇 |
2011年 | 31261篇 |
2010年 | 18338篇 |
2009年 | 16567篇 |
2008年 | 27003篇 |
2007年 | 28917篇 |
2006年 | 28980篇 |
2005年 | 28675篇 |
2004年 | 26373篇 |
2003年 | 25434篇 |
2002年 | 24092篇 |
2001年 | 37596篇 |
2000年 | 38388篇 |
1999年 | 32937篇 |
1998年 | 10612篇 |
1997年 | 9884篇 |
1996年 | 9552篇 |
1995年 | 9014篇 |
1994年 | 8549篇 |
1992年 | 27226篇 |
1991年 | 26581篇 |
1990年 | 26056篇 |
1989年 | 25062篇 |
1988年 | 23525篇 |
1987年 | 23146篇 |
1986年 | 21952篇 |
1985年 | 21257篇 |
1984年 | 16457篇 |
1983年 | 14039篇 |
1982年 | 8888篇 |
1979年 | 16757篇 |
1978年 | 12114篇 |
1977年 | 10181篇 |
1976年 | 9328篇 |
1975年 | 10147篇 |
1974年 | 12641篇 |
1973年 | 12136篇 |
1972年 | 11538篇 |
1971年 | 10685篇 |
1970年 | 10218篇 |
1969年 | 9909篇 |
1968年 | 8900篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Serial peritoneal macrophage function studies in new and established continuous ambulatory peritoneal dialysis patients 总被引:1,自引:0,他引:1
Peritoneal macrophages (PM) perform first-line defense activity against peritonitis, the most important complication in continuous ambulatory peritoneal dialysis (CAPD) therapy. Our longitudinal study has compared the PM function in 20 uremic patients during periods free of peritonitis since they started CAPD therapy in January 1987. The results showed that at the initiation of CAPD, there was a higher bactericidal activity, phagocytosis index, H2O2 production and interleukin-1 (IL-1), gamma-interferon (IFN-gamma) and tumor necrosis factor (TNF) production ability and MHC expression. As time went on, these progressively decreased, and by 9 months after CAPD therapy had started they were significantly lower than at the beginning. During the 1.5-year follow-up period, there was a significantly increased peritonitis rate in the period 6 months after the beginning of CAPD than in the period before the 6th month (88.3 vs. 11.7% respectively; p less than 0.001). These results indicate that PM of new CAPD patients have a more active function than those of established patients. The established patients had a greater risk of peritonitis. A comparison of the immunological profiles of PM from patients who had a peritonitis history shows that phagocytosis index, bactericidal activity and IL-1 and TNF production of PM were significantly decreased during the period free of peritonitis. This result suggests that these parameters may serve as an indicator in developing peritonitis. 相似文献
992.
Scoliosis in pediatric spinal cord-injured patients 总被引:1,自引:0,他引:1
W W Dearolf R R Betz L C Vogel J Levin M Clancy H H Steel 《Journal of pediatric orthopedics》1990,10(2):214-218
One hundred thirty children who sustained spinal cord injuries between birth and age 21 years were reviewed to determine the progression rate of paralytic scoliosis and the effects of bracing and surgery. Patients were divided into two groups: those injured before and those injured after the adolescent growth spurt. Scoliosis developed in 97 and 52%, respectively. Bracing was effective in delaying progression in the preadolescent group. The progressive paralytic spinal deformity did not appear to be related to the level of injury. The older patient is at much less risk for paralytic scoliosis, but still requires routine examination. 相似文献
993.
Acute viral myocarditis A death associated with anaesthesia 总被引:1,自引:0,他引:1
The death of a 35-year-old woman in the immediate postoperative period as a result of undiagnosed acute viral myocarditis is described. The presentation, diagnosis and course of the disease is discussed. It is recommended that wider use to be made of routine electrocardiographs as a screening test. 相似文献
994.
995.
Development of grating acuity in infants with regressed stage 3 retinopathy of prematurity 总被引:4,自引:0,他引:4
The acuity card procedure was used to measure grating acuity in 17 infants with regressed Stage 3 retinopathy of prematurity (ROP) who had no lasting anatomic changes in the retina or optic nerve. Results were compared with those of 28 healthy preterm infants and 28 infants matched by birth weight and gestational age who did not have Stage 3 ROP. Infants in the ROP group showed delayed grating acuity development until 2 years of age. This difference among groups was significant at the 3-5- and 10-12-month test ages but not at the 0-1-, 8-9-, and 16-18-month test ages. Post hoc analyses indicated that the delay in acuity development shown by the ROP group was due to the poor acuity scores of the infants in that group who had central nervous system abnormalities of periventricular leukomalacia or severe (Grade III or IV) intraventricular hemorrhage. When the data of these infants were removed from the analysis, the ROP group showed acuity development similar to that of both the healthy preterm group and the group of infants with matched birth weights and gestational ages who did not have Stage 3 ROP. 相似文献
996.
A B Fulton J Dodge J L Schremser A Armstrong F Lanier W W Dawson T P Williams 《Current eye research》1990,9(12):1211-1216
The content of rhodopsin in the eyes of 15 donors (30 eyes) was determined. Both retinal and pigment epithelial fractions were collected from each globe, extracted using 1% CTAB, and the rhodopsin difference spectrum of each fraction was obtained separately. The total amount of rhodopsin, obtained by summing the amounts recovered from the retinal and PE fractions, ranged from 2.00 to 11.94 (median: 6.40) nmoles/eye. Previously reported mean values of about 3.5 to 4.0 nmoles per retina have been obtained using a variety of methods. The present higher values, perhaps largely dependent on procedural details described herein, appear plausible given the known concentrations of rhodopsin in rod outer segments, rod outer segment volumes, and number of rods in the human retina. 相似文献
997.
Relaxing retinotomies. Analysis of anatomic and visual results 总被引:6,自引:0,他引:6
The authors analyzed 100 consecutive eyes undergoing relaxing retinotomies to determine the anatomic and visual results associated with the use of this procedure. With a minimum follow-up of 6 months, 58 eyes were completely attached, 8 were partially attached (macula on), and 34 were detached. Thirty-four percent of all eyes and 50% of attached eyes obtained a visual acuity of 5/200 or greater at 6 months. At last examination, 29% of all eyes and 43% of attached eyes had a visual acuity of at least 5/200. Eyes that had circumferential relaxing retinotomies involving the entire temporal quadrant generally had lower visual acuities when compared with eyes that had relaxing retinotomies sparing the entire temporal quadrant. The use of a radial relaxing retinotomy also was associated with lower final visual acuity. The length of the relaxing retinotomy or the placement of the relaxing retinotomy either anterior or posterior to the encircling scleral buckle did not appear to influence the anatomic or visual results. Hypotony (intraocular pressure less than 5 mmHg) was seen in 43% of reattached eyes. 相似文献
998.
The intraocular pressure and the anteroposterior length of the eye are of great clinical importance for the diagnosis and management, before and after surgery, of congenital glaucoma. It is well-known that normal intraocular pressure in children is different from the normal levels in adults. We performed measurements of intraocular pressure and axial length in 141 children who had been admitted for eye problems other than glaucoma. The intraocular pressures were measured with the Perkins hand-held applanation tonometer at the beginning of general anesthesia. Simultaneously, A-scan ultra-sound measurements of the axial lengths of the eyes were made. In 10 children under the age of two years, the intraocular pressure was 11.85 +/- 1.35 mmHg. In 79 children from two to seven years, the intraocular pressure was 12.80 +/- 1.73 mmHg. In 52 children from seven to 15 years, the intraocular pressure was 13.31 +/- 1.79 mmHg. The axial lengths of the eyes in children under the age of two years, from two to seven years, and from seven to 15 years, were 21.31 +/- 0.97 mm, 22.04 +/- 0.92 mm, and 23.22 +/- 1.00 mm, respectively. These results were considered to be guidelines for measuring intraocular pressure and axial length in children suspected of having congenital glaucoma. The differences of intraocular pressures stated by other authors are due to early measurement of the intraocular pressure at the beginning of general anesthesia. 相似文献
999.
Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study. 总被引:1,自引:0,他引:1
The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma. 相似文献
1000.
The effect of concomitant disorders in childhood depression on predicting treatment response 总被引:2,自引:0,他引:2
C W Hughes S H Preskorn E Weller R Weller R Hassanein S Tucker 《Psychopharmacology bulletin》1990,26(2):235-238
Children with pure depression or depression plus an anxiety-related disorder (n = 14) had a higher drug response rate (57%) and a lower placebo response rate (20%) when compared to children with depression plus a concomitant conduct or oppositional disorder (n = 17) (33% drug response rate and 67% placebo response rate). These findings could explain why studies of prepubertal-onset depression found no differences between drug and placebo treatment assuming that a large percentage of the studies' subjects had concomitant conduct or oppositional disorders. The children with pure depression or depression plus an anxiety-related disorder had different symptom clusters from those with depression plus a concomitant conduct or oppositional disorder. The former had more severe CDRS ratings on sleep, appetite disturbance, depressed feelings, and psychomotor retardation. In contrast, those with a concomitant conduct or oppositional disorder had shorter attention spans and were more likely to disturb other children (based on Conners scale scores). 相似文献