全文获取类型
收费全文 | 3521598篇 |
免费 | 266082篇 |
国内免费 | 6885篇 |
专业分类
耳鼻咽喉 | 49735篇 |
儿科学 | 112118篇 |
妇产科学 | 94661篇 |
基础医学 | 495717篇 |
口腔科学 | 103128篇 |
临床医学 | 320719篇 |
内科学 | 681240篇 |
皮肤病学 | 74903篇 |
神经病学 | 286202篇 |
特种医学 | 136557篇 |
外国民族医学 | 1084篇 |
外科学 | 531087篇 |
综合类 | 84000篇 |
现状与发展 | 5篇 |
一般理论 | 1394篇 |
预防医学 | 278443篇 |
眼科学 | 84220篇 |
药学 | 262397篇 |
11篇 | |
中国医学 | 7487篇 |
肿瘤学 | 189457篇 |
出版年
2018年 | 37581篇 |
2017年 | 28726篇 |
2016年 | 31772篇 |
2015年 | 36006篇 |
2014年 | 51171篇 |
2013年 | 76930篇 |
2012年 | 104774篇 |
2011年 | 110746篇 |
2010年 | 65591篇 |
2009年 | 61944篇 |
2008年 | 104130篇 |
2007年 | 110915篇 |
2006年 | 111870篇 |
2005年 | 108520篇 |
2004年 | 104550篇 |
2003年 | 100315篇 |
2002年 | 98097篇 |
2001年 | 166755篇 |
2000年 | 172007篇 |
1999年 | 144798篇 |
1998年 | 41123篇 |
1997年 | 36680篇 |
1996年 | 36344篇 |
1995年 | 35162篇 |
1994年 | 32824篇 |
1993年 | 30426篇 |
1992年 | 114834篇 |
1991年 | 111169篇 |
1990年 | 107273篇 |
1989年 | 103618篇 |
1988年 | 95685篇 |
1987年 | 93982篇 |
1986年 | 88846篇 |
1985年 | 84752篇 |
1984年 | 63812篇 |
1983年 | 54377篇 |
1982年 | 32215篇 |
1981年 | 28771篇 |
1979年 | 58790篇 |
1978年 | 41064篇 |
1977年 | 34890篇 |
1976年 | 32650篇 |
1975年 | 34467篇 |
1974年 | 42421篇 |
1973年 | 40474篇 |
1972年 | 37889篇 |
1971年 | 34987篇 |
1970年 | 32871篇 |
1969年 | 30587篇 |
1968年 | 28086篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
J Somerville 《British journal of hospital medicine》1990,43(2):132-136
'Grown-up' congenital cardiac patients are an increasing medical community, not at present being properly cared for in any country. Information on over 2000 patients aged 15-65 years with congenital heart disease who have been treated in the National Heart Hospital provides the data for this report. 相似文献
992.
1. Effects of a novel imidazoindole derivative on cholinergic function were studied in isolated tissue preparations. 2. The compound demonstrated a dose-dependent (10(-11)-10(-9) potentiation (20-60%) of acetylcholine induced tension in guinea pig ileal tissue. 3. Increases in the size of end-plate potentials and nerve evoked muscle twitches were observed in frog nerve-skeletal muscle preparations. 4. Cholinesterase activity was not inhibited. 5. The results suggest that the compound has actions at the post-synaptic muscarinic receptor complex in smooth muscle and causes pre-synaptic increases in ACh release at the neuromuscular junction. 相似文献
993.
Absorption mechanism and absorption site of a prodrug of L-DOPA, L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (NB-355, 1) was investigated using rats. Prodrug 1 (0.5 mM) was taken up by intestinal tissue segments time-dependently in vitro at pH 6.0. However, the rate of uptake was less than that of L-dopa. Inhibitors of the amino acid active transport system (L-Phe, dinitrophenol, ouabain) had no effect on the uptake of prodrug 1. In the intestinal tissue segments, prodrug 1 was extensively hydrolyzed by diisopropylfluorophosphate-sensitive esterase(s). To characterize the absorption site, gastrointestinal tracts were ligated to make acute loops in situ and prodrug 1 or L-dopa was injected into the loops. L-dopa disappeared rapidly from the lumen of the jejunum. In contrast, prodrug 1 disappeared rapidly from the ileum rather than the duodenum or jejunum. From these results, it was suggested that prodrug 1 was slowly absorbed primarily from the lower small intestine. 相似文献
994.
A novel method for culturing sweat gland epithelia: comparison of normal and cystic fibrosis tissues. 下载免费PDF全文
A new method is described to produce epithelial sheets by direct explantation of human sweat glands onto matrigel-coated millipore filters. The method is applicable to whole glands, separated coils or ducts and to normal and CF tissues. Electrogenic transport studies show that epithelia develop sodium transporting capability, even when explants are derived from secretory coils. 相似文献
995.
Effects of hypothermia on testicular ischemia 总被引:14,自引:0,他引:14
The ischemic effects of prolonged testicular torsion have been well documented; however, prevention or arrest of the damaging effects of prolonged ischemia has been incompletely studied. Two groups of Sprague-Dawley rats were subjected to varying lengths of bilateral testicular ischemia. Group I underwent normothermic ischemia for two, four, and six hours. Likewise, Group II underwent similar time periods of ischemia, however, after thirty minutes of normothermic ischemia the scrotum of each animal was placed into an ice bath maintained at 4C. Two weeks postoperatively, bilateral orchiectomy was performed. Histology of the testes of the two groups was compared. Neither group revealed significant destruction of the germinal epithelium after two hours of ischemia. Group I revealed only 25% preservation of the germinal epithelium at four hours and only 8% preservation at six hours of ischemia. In contrast, Group II which received ice showed 90% preservation of germinal epithelium at four hours and 85% preservation at six hours of ischemia. We conclude that external ice application significantly preserves seminiferous tubules at four and six hours of ischemic injury in the rat testicle. 相似文献
996.
We report a case of recurrent calculi in a Kock pouch continent urinary diversion. An open operation was avoided by successfully excising the Marlex mesh and removing it with the associated calculi in an endoscopic fashion. 相似文献
997.
998.
K Y Mumcuoglu J Miller R Gofin B Adler F Ben-Ishai R Almog D Kafka S Klaus 《Public health reviews》1990,18(4):335-344
BACKGROUND: The aim was to determine the influence of the socioeconomic status of the family and the hygienic practices in the home on the prevalence of head lice infestation in children. METHODS: The study was carried out by analyzing the answers to a standardized epidemiological questionnaire given to parents of school children aged 4-17 in Bet Shemesh, a medium-sized urban town 25 km from Jerusalem. RESULTS: Of 3,000 questionnaires distributed, 958 (31.9%) were completed and returned. The majority of the children (72.4%) had been previously infested with lice. Half of them had other family members, mainly brothers and sisters, who had been infested in the past with lice. In 97.5% of the families the mother was responsible for examining the children for lice, and for carrying out treatment when infestation was present. An association was found between presence of lice infestation and mother's education, age of child, and frequency of shampooing, combing, and examination for lice. There was no association between infestation rates and mother's country of origin, crowding in the home, and the sharing of combs, brushes, hats, scarves, towels, and clothes. CONCLUSIONS: There is evidence that the incidence of lice infestation depends on the hygienic practices in the home rather than on the socioeconomic status of the family or sharing of personal articles among family members. 相似文献
999.
Studies were undertaken to determine if computed tomography (CT) could reliably assist physical examination in the initial assessment of blunt abdominal trauma, and also to examine how various abdominal injuries were managed with the guidance of CT. A total of 255 patients underwent emergency abdominal CT following blunt abdominal trauma over a period of seven years. One hundred and fifty two patients had abnormal CT scans, including 58 hepatic, 36 renal, 25 splenic and 9 pancreatic injuries as well as 67 patients with intra-abdominal hemorrhage and 21 patients with free abdominal air. A comparative study on the detection of pneumoperitoneum revealed CT to be far superior to plain radiography. One hundred and three patients had normal CT scans, all of whom were managed nonoperatively, except for three false-negative cases and two nontherapeutic cases. The patients with injury to the parenchymal organs were given nonoperative treatment if they had stable vital signs and no evidence of associated injuries demanding immediate surgery and the majority of these patients were managed well nonoperatively. CT was thus found to be a useful adjunct in the management of victims of blunt abdominal trauma, since in a rapid and noninvasive fashion, CT accurately defined the extent of parenchymal organ injury and also disclosed any other abdominal injuries. 相似文献
1000.
R D Perrone T I Steinman G J Beck C I Skibinski H D Royal M Lawlor L G Hunsicker 《American journal of kidney diseases》1990,16(3):224-235
Assessment of glomerular filtration rate (GFR) with inulin is cumbersome and time-consuming. Radioisotopic filtration markers have been studied as filtration markers because they can be used without continuous intravenous (IV) infusion and because analysis is relatively simple. Although the clearances of 99mTc-diethylenetriamine-pentaacetic acid (DTPA), 169Yb-DTPA, and 125I-iothalamate have each been compared with inulin, rarely has the comparability of radioisotopic filtration markers been directly evaluated in the same subject. To this purpose, we determined the renal clearance of inulin administered by continuous infusion and the above radioisotopic filtration markers administered as bolus injections, simultaneously in four subjects with normal renal function and 16 subjects with renal insufficiency. Subjects were studied twice in order to assess within-study and between-study variability. Unlabeled iothalamate was infused during the second half of each study to assess its effect on clearances. We found that renal clearance of 125I-iothalamate and 169Yb-DTPA significantly exceeded clearance of inulin in patients with renal insufficiency, but only by several mL.min-1.1.73m-2. Overestimation of inulin clearance by radioisotopic filtration markers was found in all normal subjects. No differences between markers were found in the coefficient of variation of clearances either between periods on a given study day (within-day variability) or between the two study days (between-day variability). The true test variability between days did not correlate with within-test variability. We conclude that the renal clearance of 99mTc-DTPA, 169Yb-DTPA, or 125I-iothalamate administered as a single IV or subcutaneous injection can be used to accurately measure GFR in subjects with renal insufficiency; use of the single injection technique may overestimate GFR in normal subjects. 相似文献