全文获取类型
收费全文 | 35696篇 |
免费 | 3722篇 |
国内免费 | 2194篇 |
专业分类
耳鼻咽喉 | 340篇 |
儿科学 | 483篇 |
妇产科学 | 476篇 |
基础医学 | 4271篇 |
口腔科学 | 563篇 |
临床医学 | 4550篇 |
内科学 | 5295篇 |
皮肤病学 | 367篇 |
神经病学 | 2335篇 |
特种医学 | 1308篇 |
外国民族医学 | 8篇 |
外科学 | 3908篇 |
综合类 | 5919篇 |
现状与发展 | 8篇 |
一般理论 | 8篇 |
预防医学 | 3111篇 |
眼科学 | 715篇 |
药学 | 3527篇 |
20篇 | |
中国医学 | 1711篇 |
肿瘤学 | 2689篇 |
出版年
2024年 | 117篇 |
2023年 | 491篇 |
2022年 | 1276篇 |
2021年 | 1551篇 |
2020年 | 1170篇 |
2019年 | 1070篇 |
2018年 | 1083篇 |
2017年 | 1029篇 |
2016年 | 947篇 |
2015年 | 1377篇 |
2014年 | 1844篇 |
2013年 | 1910篇 |
2012年 | 2620篇 |
2011年 | 2817篇 |
2010年 | 2061篇 |
2009年 | 1671篇 |
2008年 | 2039篇 |
2007年 | 2059篇 |
2006年 | 2012篇 |
2005年 | 1699篇 |
2004年 | 1429篇 |
2003年 | 1573篇 |
2002年 | 1294篇 |
2001年 | 873篇 |
2000年 | 800篇 |
1999年 | 615篇 |
1998年 | 407篇 |
1997年 | 327篇 |
1996年 | 261篇 |
1995年 | 213篇 |
1994年 | 196篇 |
1993年 | 144篇 |
1992年 | 199篇 |
1991年 | 217篇 |
1990年 | 206篇 |
1989年 | 174篇 |
1988年 | 184篇 |
1987年 | 136篇 |
1986年 | 174篇 |
1985年 | 143篇 |
1984年 | 105篇 |
1983年 | 100篇 |
1982年 | 59篇 |
1981年 | 66篇 |
1979年 | 78篇 |
1978年 | 59篇 |
1977年 | 59篇 |
1976年 | 58篇 |
1974年 | 61篇 |
1973年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Chromosome mapping of Rett syndrome: a likely candidate region on the telomere of Xq. 总被引:7,自引:5,他引:2 下载免费PDF全文
F Xiang Z Zhang A Clarke P Joseluiz N Sakkubai B Sarojini C D Delozier-Blanchet I Hansmann L Edstr?m M Anvret 《Journal of medical genetics》1998,35(4):297-300
Rett syndrome (RS) is a disease of neurological development. First reported 30 years ago in 1966, its biological and genetic basis remains obscure. RS is commonly thought of as an X linked dominant disorder lethal to hemizygous males. The few familial cases would arise through mosaicism or because of occasional females failing to manifest the disorder through skewed X inactivation in relevant cell types. We have one family where the mother and daughter are affected with RS, and which can be explained according to this hypothesis. If the alternative proposal of Thomas (1996) is correct, that the lack of males affected by such disorders is the result of a high male to female ratio of germline mutations rather than of gestational lethality, then the RS gene should be located on the grandpaternal chromosome. Genomic screening with markers covering the whole X chromosome has been performed. Studies using multiple informative markers indicate that the RS locus is likely to be located close to one of the X chromosome telomeres. Further investigations in eight additional families suggest the most likely region for the RS gene to be is the distal part of Xq (Xq28). 相似文献
32.
C P Gibbons C B Summerton P G McNally R Kay C B Brown A T Raftery 《Transplantation》1986,41(4):464-467
Postoperative intrarenal pressure measurements may be an aid to the diagnosis of acute renal transplant rejection, especially in patients treated with cyclosporine. Serial measurements of intrarenal pressure were made in 38 recipients using a fine-needle technique. Thirty-two intraoperative and 207 postoperative measurements were made, and 39 clinical rejection episodes (23 confirmed by biopsy) monitored. Intraoperative pressures in grafts with immediate function (37.4 +/- 4.0 mmHg, mean +/- SEM) were not significantly different from those with delayed function (30.9 +/- 4.8 mmHg), whereas postoperative pressures were greater (P less than 0.01) in kidneys with acute tubular necrosis (29.4 +/- 1.9 mmHg) than in functioning grafts (20.4 +/- 0.9 mmHg). Pressures recorded during clinical rejection episodes (44.3 +/- 2.3 mmHg) exceeded (P less than 0.001) those during quiescent periods (23.6 +/- 1.0 mmHg). During rejection episodes, higher pressures (P less than 0.01) were recorded from tender or palpably enlarged grafts (52.5 +/- 3.0 mmHg) than in the absence of these signs (36.3 +/- 3.1 mmHg), and patients whose transplants biopsies showed cellular rejection tended to have greater pressures (50.1 +/- 4.1 mmHg) than those with concomitant vasculopathy (36.4 +/- 3.9 mmHg), but the latter did not reach statistical significance. In 7 cases of cyclosporine toxicity the intrarenal pressure was 17.8 +/- 4.2 mmHg. Using a diagnostic cut off point of 40 mmHg, the investigation failed to recognize 26% of acute rejection episodes--and, in the presence of acute tubular necrosis, it wrongly categorized 21% of nonrejectors. While its predictive capacity was limited, the test may occasionally be helpful in the differentiation of cyclosporine toxicity and rejection in functioning kidneys. 相似文献
33.
[目的]研究大豆蛋白对肾损害大鼠钙平衡的影响。[方法]选择3月龄断乳雄性SD大鼠40只.按体质量从小到大排序,采用完全随机化原则分为4组。每组10只。标准饲料对照组:喂食含有14%酪蛋白饲料;大豆蛋白饲料组:喂食含有14%大豆分离蛋白饲料;混合饲料1组:喂食含有7%酪蛋白加7%大豆分离蛋白饲料;混合饲料2组:喂食含有7%酪蛋白加14%大豆分离蛋白饲料。实验期用腺嘌呤灌胃共21d,建立肾损害大鼠模型,各组大鼠喂养相应饲料6周,测饲料消耗量、24h尿蛋白、尿钙、钙表观吸收率、储留钙量。[结果]4组实验大鼠饲料摄入量1d~30d无统计学差异,大豆蛋白饲料组和混合饲料1组实验结束时与另外两组相比,尿钙排泄量低,钙表观吸收率和储留钙量高,差异有统计学意义(P〈0.05)。[结论]蛋白质含量水平在14%条件下,含大豆蛋白的两种饲料对肾损害大鼠钙吸收、钙排泄的影响无统计学差异,有利于促进钙吸收,减少钙排泄。 相似文献
34.
Hisashi Masugata Shoichi Senda Fuminori Goda Yumiko Yoshihara Kay Yoshikawa Norihiro Fujita Hiroyuki Daikuhara Hiroyuki Nakamura Teruhisa Taoka Masakazu Kohno 《Hypertension research》2006,29(11):897-903
The purpose of the present study was to elucidate the cardiac structure and function in patients who have metabolic syndrome but no history of cardiovascular disease by analyzing echocardiographic findings. Echocardiographic examination was performed to screen for cardiovascular disease in 135 patients who were in their sixties. Patients were divided into metabolic syndrome (n=65, age: 65+/-2.7 years) and non-metabolic syndrome (n=70, age: 66+/-2.5 years) groups based on the criteria for metabolic syndrome proposed by the Japanese Society of Hypertension and seven other societies in 2005. The left ventricular (LV) wall thickness and dimension were measured by M-mode echocardiography. The relative wall thickness, LV mass index, and LV ejection fraction (LVEF) were calculated. LV diastolic function was assessed by the peak velocity of early rapid filling (E velocity) and the peak velocity of atrial filling (A velocity), and the ratio of E to A (E/A) was assessed by the transmitral flow. The Tei index, which reflects both LV diastolic and systolic function, was also calculated. There were no differences in relative wall thickness, LV mass index, or LVEF between the two groups. However, both the EIA and Tei index were significantly different between the metabolic syndrome (0.66+/-0.14 and 0.36+/-0.07, respectively) and non-metabolic syndrome (0.88+/-0.25 and 0.29+/-0.09) groups (p<0.001). These results indicate that patients with metabolic syndrome can have cardiac diastolic dysfunction even if they have neither LV hypertrophy nor systolic dysfunction. 相似文献
35.
36.
Protein concentration and acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were assayed in the cerebrospinal fluid (CSF) of 26 healthy normal subjects (20-86 years old), 27 patients with dementia of the Alzheimer type (DAT), and 10 patients with dementia of the Alzheimer type with extrapyramidal signs (EDAT). In normal subjects, there was an age-related increase in CSF protein and AChE activity and a significant correlation (p less than 0.001) between CSF protein and BChE activity. In the DAT and EDAT groups, CSF AChE activities (mean +/- SD = 17.5 +/- 3.6 and 15.3 +/- 4.4 nmol/min/ml, respectively) were significantly lower (p less than 0.05) than in 13 age-matched control subjects (21.5 +/- 5.6 nmol/min/ml). In contrast, neither CSF protein concentration, BChE activity, nor the ratio of AChE/BChE differed significantly between groups. In patients with DAT, CSF AChE activity was significantly lower (p less than 0.05) in subjects with an early onset compared to those with a late onset (16.4 +/- 3.4 and 19.7 +/- 2.8 nmol/min/ml, respectively), and activity in the latter group did not differ significantly from control values. CSF AChE activity was not related to dementia severity and did not change significantly over an 18-month period. Although these results confirm a cholinergic deficit in patients with DAT, the considerable overlap of CSF AChE activity between groups and the nonsignificant correlation between AChE activity and dementia severity limit the usefulness of CSF AChE as a diagnostic marker of this disorder. 相似文献
37.
38.
OBJECTIVE: To study the expression of neuron-specific enolase (NSE) and olfactory marker protein (OMP) in the developing olfactory mucosa of human fetuses. METHOD: The expression of NSE and OMP in the olfactory mucosa of 6 human fetuses (12, 16, 20, 24, 28 and 34 weeks) was studied using the technique of immunohistochemistry. RESULTS: NSE immunological positive reactions were seen in all 6 fetal mucosa from gestational 12 (G12) to G34, with plenty of positive-stained dual-pole neuron cells. At G12, the positive cells aligned tightly, the cell bodies were localized in the lower portion of olfactory epithelium and the positive-stained area occupied upper 2/3 of fetal nasal mucosa. With the development, the positive cells gradually became multilayer, but the density and the relative area of positive-cells reduced. At G34, the positive cells were located only in upper 1/3 of nasal mucosa. OMP-positive reactions were localized in a few dual-pole neurons at G12, the number was much less than NSE-positive cells in the same fetus. With the development, the OMP-positive cells gradually increased with most of the cell bodies located in the upper portion of epithelium, but number still relatively less than the NSE-positive cells at the same age. CONCLUSION: At G12, there were lots of olfactory neuron in the olfactory mucosa and only a few olfactory neurons had became mature. With the development, the olfactory epithelial area reduced but the number of mature olfactory neurons increased. At the last trimester, fetal olfactory sensor was almost matured. 相似文献
39.
Primary cultures of adult rat hepatocytes were used to investigate the effects of two putative therapeutic agents, dithioerythritol and silymarin on microcystin-LR-induced hepatotoxicity. Cell injury was assessed by the extent of cellular [14C]adenine nucleotides and lactate dehydrogenase (LDH) release into the medium and the extent of hepatocyte detachment from monolayers. Microcystin-LR (1 µM) induced a significant release of both 14C-labeled nucleotides and LDH from hepatocytes as well as significant detachment of cells from monolayers. Although both dithioerythritol (0.63–5 mM) and silymarin (25–200 µM) reduced the amount of marker release and cell detachment from microcystin-LR-treated wells, silymarin provided significantly greater protection than dithioerythritol at one-tenth the concentration. Furthermore, silymarin and dithioerythritol treatment prevented morphological deformations and detachment of cells. 相似文献
40.
目的 :探讨胫腓骨远端骨折治疗术式的选择、术中术后应注意的问题及其疗效。方法 :对不同类型的胫腓骨远端骨折 36例进行 8~ 18个月的随访 ,并结合临床及影像学资料 ,对其诊断、手术方法及治疗效果进行分析总结。结果 :本组术后 2 5~ 3 5个月骨折均愈合。踝关节功能优良率 77 7%。结论 :熟悉骨折的分型及相应内固定术式的选择 ;注重踝穴骨折的解剖复位及固定和踝关节的功能位固定及早期功能锻炼。 相似文献