全文获取类型
收费全文 | 8436篇 |
免费 | 379篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 274篇 |
妇产科学 | 173篇 |
基础医学 | 1072篇 |
口腔科学 | 129篇 |
临床医学 | 474篇 |
内科学 | 2056篇 |
皮肤病学 | 87篇 |
神经病学 | 551篇 |
特种医学 | 269篇 |
外科学 | 1556篇 |
综合类 | 48篇 |
预防医学 | 190篇 |
眼科学 | 466篇 |
药学 | 532篇 |
中国医学 | 16篇 |
肿瘤学 | 886篇 |
出版年
2023年 | 42篇 |
2022年 | 82篇 |
2021年 | 140篇 |
2020年 | 77篇 |
2019年 | 109篇 |
2018年 | 137篇 |
2017年 | 106篇 |
2016年 | 151篇 |
2015年 | 169篇 |
2014年 | 228篇 |
2013年 | 305篇 |
2012年 | 429篇 |
2011年 | 516篇 |
2010年 | 256篇 |
2009年 | 242篇 |
2008年 | 479篇 |
2007年 | 473篇 |
2006年 | 496篇 |
2005年 | 478篇 |
2004年 | 485篇 |
2003年 | 454篇 |
2002年 | 472篇 |
2001年 | 230篇 |
2000年 | 214篇 |
1999年 | 236篇 |
1998年 | 105篇 |
1997年 | 99篇 |
1996年 | 81篇 |
1995年 | 98篇 |
1994年 | 80篇 |
1993年 | 59篇 |
1992年 | 128篇 |
1991年 | 122篇 |
1990年 | 87篇 |
1989年 | 115篇 |
1988年 | 92篇 |
1987年 | 106篇 |
1986年 | 125篇 |
1985年 | 88篇 |
1984年 | 68篇 |
1983年 | 47篇 |
1981年 | 27篇 |
1980年 | 25篇 |
1979年 | 33篇 |
1978年 | 19篇 |
1977年 | 26篇 |
1975年 | 18篇 |
1974年 | 22篇 |
1970年 | 24篇 |
1969年 | 25篇 |
排序方式: 共有8856条查询结果,搜索用时 12 毫秒
51.
A signal separation method for extracting background electroencephalogram (EEG) from EEG containing spikes was proposed. Morphological filters were designed for extracting spike waveforms, and then the background EEG was obtained by subtracting the detected spike waveforms from the EEG with spike. The proposed method was evaluated by using simulated EEG data, which consisted of a summation of EEG without spike and model waveform of typical spike. The background EEG separated by the method was processed by the automatic background EEG interpretation. 相似文献
52.
53.
A number of experiments were conducted to compare the ability of observers to extract unidirectional and bidirectional (transparent) global-motion signals. In the unidirectional condition, the noise signal consisted of purely randomly-moving dots while in the bidirectional condition, a number of the randomly moving dots were replaced by the same number of dots moving in a specific (secondary-signal) direction. The threshold measure was the minimum number of signal dots required to determine the global-motion direction. For the bidirectional condition, parameters varied were the angular separation between the global-motion and secondary-signal directions and the strength of the secondary signal. Thresholds for unidirectional and bidirectional conditions were the same when the angular difference between global-motion and secondary-signal directions were 90 degrees or greater, i.e. the ability of observers to extract a transparent signal was the same as their ability to extract a unidirectional one. Similarly, with motion-in-depth signals, thresholds for extracting a centripetal signal were not elevated by replacing a number of the randomly-moving noise dots with the same number centrifugally-moving dots. The results are interpreted as indicating that motion signals moving between 90 and 180 degrees to the global-motion direction provide uniform masking of the global-motion signal. For angular separations less than 90 degrees, a suprathreshold secondary signal resulted in threshold elevation. This result could be due, to stronger inhibition from motion units tuned to similar (< 90 degrees) directions, broad directional-tuning of the underlying motion units (changing the task from signal detection to a signal discrimination) or a combination of the two. 相似文献
54.
Apolipoproteins J and E co-localise with amyloid in gelatinous drop-like and lattice type I corneal dystrophies 下载免费PDF全文
K. Nishida A. Quantock A. Dota N. Choi-Miura S. Kinoshita 《The British journal of ophthalmology》1999,83(10):1178-1182
AIMS: Apolipoprotein J (apoJ) and apolipoprotein E (apoE) are thought to contribute to amyloid formation in patients with Alzheimer's disease. The aim of this investigation was to discover whether or not these apolipoproteins associate with corneal amyloid in gelatinous drop-like corneal dystrophy (GDCD) and lattice corneal dystrophy type I (LCD-I). METHODS: Corneas from three eyes of three patients with GDCD and one eye of one patient with LCD-I were examined immunohistochemically using antibodies against apoJ and apoE. Two normal corneas were similarly examined. Tissue sections of brain from a patient with Alzheimer's disease were used as positive controls for the antibodies. For all negative controls, mouse IgG was used instead of the primary antibody. RESULTS: Intense apoJ and apoE immunoreactivities were found in congophilic amyloid deposits in GDCD and LCD-I. These deposits were located subepithelially in GDCD, and subepithelially and intrastromally in LCD-I. In GDCD, immunostaining of subepithelial amyloid with anti-apoJ was noticeably stronger than with anti-apoE. CONCLUSIONS: As in senile plaques in brain from a patient with Alzheimer's disease, apoJ and apoE co-localise with amyloid in corneas with GDCD and LCD-I. 相似文献
55.
Makoto Komura Yoshiaki Tsuchida Toshiro Honna Yoshiyuki Kamii Shu-ichiro Kitahara Shin-pachi Ishizone 《Pediatric surgery international》1993,8(2):157-161
A case showing many of the typical visceral features of cloacal exstrophy is reported. The patient had fn imperforate anus, a cecal-cloacal fistula, dehiscence of the pubiic symphysis, and lumbosacral spina bifida with synsingomyelia, but the lower abdominal wall was intact without any visceral extroversion. The pertinent literature was reviewed, and it was found that this case corresponded to t typical case of completely covered cloacal exstrophy. Only six cases, including the present one, have so far been reported in the literature. From a clinical viewpoint, it apparently occupies an intermediate position in the wide spectrum of cloacal anomalies between classical cloacal exstrophy and imperforate anus with recto-cloacal fistula, but anatomatically and embryologically it is definitely a variant of cloacal exstrophy. In other words, it looks like an imperforate anus with recto-cloacal exstrophy, but should be treated as a variant of loacal exstrophy. The anatomy, classification, embryology, diagnosis, and management of this peculiar surgical condition are discussed, and recognition of this entity is urged. 相似文献
56.
Honda O Nishimura M Tomiyama N Johkoh T Mihara N Kozuka T Naito H Hamada S Kagawa K Nishida T Ichikawa Y Yamamoto S Nakamura H 《Investigative radiology》2000,35(9):534-538
RATIONALE AND OBJECTIVES: To investigate whether expiratory high-resolution computed tomography (HRCT) is more useful than inspiratory HRCT for the detection of early-phase diffuse alveolar damage. METHODS: Eleven anesthetized rabbits were scanned with both inspiratory and expiratory HRCT every 30 minutes during mechanical ventilation. Ten rabbits were killed after the detection of pulmonary abnormalities on both inspiratory and expiratory HRCT. The remaining rabbit was killed when the pulmonary abnormalities appeared only on expiratory HRCT. RESULTS: In four cases (36%), the abnormal findings were detected earlier on expiratory HRCT than on inspiratory HRCT. In seven cases (64%), the abnormalities appeared simultaneously on inspiratory and expiratory HRCT. In all 11 cases, the histopathological changes of areas with abnormal CT findings corresponded to the exudative or proliferative phase of diffuse alveolar damage. CONCLUSIONS: Expiratory HRCT has the potential to detect the abnormalities of diffuse alveolar damage earlier than inspiratory HRCT. 相似文献
57.
58.
Yajima M Baba K Yanagisawa N Nishida T Yamakawa K Takemura H Nishida S Iwamoto T 《Hinyokika kiyo. Acta urologica Japonica》2000,46(4):247-250
From December 1996 to June 1998, we performed transurethral surgery of the prostate using a thick loop, VaporTome developed by Circon ACMI on 23 patients with symptomatic benign prostatic hyperplasia (BPH). The mean international prostate symptom score decreased significantly, from 22.6 at baseline to 9.0, 6.5, 4.9 and 5.3 at 1, 3, 6 and 12 months after operation, respectively. The mean quality of life index also decreased significantly, from 5.5 to 1.8, 1.8, 1.4 and 1.2, respectively. The mean peak flow rate increased significantly, from 6.2 preoperatively to 15.8, 17.1, 16.6 and 17.4 ml/sec at 1, 3, 6 and 12 months after operation, respectively. The mean prostate volume decreased significantly, from 66.9 to 24.8, 17.3, 19.0 and 18.2 ml. The mean residual urine decreased significantly, from 167.9 to 11.4, 9.4, 12.8 and 20.4 ml. As for overall efficacy, the rate of excellent and good cases at 1, 3, 6 and 12 months was 80.9, 89.4, 94.7 and 85.8%, respectively. No serious complications were observed. Our clinical results suggest that transurethral surgery for BPH using VaporTome has several potential advantages including high efficacy, minimal morbidity compared with standard transurethral resection of the prostate and lower cost compared with other minimally invasive procedures. 相似文献
59.
No Improvement of Adult Height in Non-growth Hormone (GH) Deficient Short
Children with GH Treatment
Toshiaki Tanaka Kenji Fujieda Susumu Yokoya Akira Shimatsu Katsuhiko Tachibana Hiroyuki Tanaka Takakuni Tanizawa Akira Teramoto Toshiro Nagai Yoshikazu Nishi Yukihiro Hasegawa Kunihiko Hanew Keinosuke Fujita Reiko Horikawa Goro Takada Masao Miyashita Tadashi Ohno Kazuo Komatsu 《Clinical Pediatric Endocrinology》2006,15(1):15-21
It is still in doubt whether the standard-dose growth hormone (GH) used in Japan (0.5
IU/kg/week, 0.167 mg/kg/week) for growth hormone deficiency is effective for achieving
significant adult height improvement in non-growth hormone deficient (non-GHD) short
children. We compared the growth of GH-treated non-GHD short children with that of
untreated short children to examine the effect of standard-dose GH treatment on non-GHD
short children. GH treatment with recombinant human growth hormone (rhGH) was started
before the age of 11 yr in 64 boys and 76 girls with non-GHD short stature registered at
the Foundation for Growth Science who have now reached their adult height. In 119
untreated boys and 127 untreated girls whose height standard deviation score (SDS) was
below –2 SD at the age of 6 yr, height growth was followed until 17 yr. Height SDS was
significantly lower before GH treatment in the GH-treated group than at the age of 6 yr in
the untreated group, in both sexes. Adult height and adult height SDS were significantly
greater in the untreated group than in the GH-treated group, in both sexes, although the
change in height SDS did not differ significantly. Height SDS was significantly lower
before GH treatment in the GH-treated group than at the age of 6 yr in the untreated
group, so 57 boys and 57 girls whose height SDS at the age of 6 yr in the untreated group
closely matched the height SDS before GH treatment in the GH-treated group were chosen for
comparison. Height SDS did not differ significantly between the GH-treated group before GH
treatment and the untreated group at the age of 6 yr, nor were there differences between
these subgroups in adult height, adult height SDS, or height SDS change, in either sex.
The effect of GH treatment is reported to be dose-dependent and doses over 0.23 mg/kg/week
are reported to be necessary to improve adult height in non-GHD short children. Currently,
the GH dose is fixed at 0.175 mg/kg/week in Japan, and we expected to find, and indeed
concluded, that ordinary GH treatment in Japanese, non-GHD short children does not improve
adult height. 相似文献
60.
Shin-ichi Fukumoto Naoko Yamauchi Hisashi Moriguchi Yoshitaka Hippo Akira Watanabe Junji Shibahara Hirokazu Taniguchi Shumpei Ishikawa Hirotaka Ito Shogo Yamamoto Hiroko Iwanari Mitsugu Hironaka Yuichi Ishikawa Toshiro Niki Yasunori Sohara Tatsuhiko Kodama Masaharu Nishimura Masashi Fukayama Hirotoshi Dosaka-Akita Hiroyuki Aburatani 《Clinical cancer research》2005,11(5):1776-1785
PURPOSE: Squamous cell carcinoma (SCC) and adenocarcinoma of the lung are currently subject to similar treatment regimens despite distinct differences in histology and epidemiology. The aim of this study is to identify a molecular target with diagnostic and therapeutic values for SCC. EXPERIMENTAL DESIGN: Genes specifically up-regulated in SCC were explored through microarray analysis of 5 SCCs, 5 adenocarcinomas, 10 small cell lung carcinomas, 27 normal tissues, and 40 cancer cell lines. Clinical usefulness of these genes was subsequently examined mainly by immunohistochemical analysis. RESULTS: Seven genes, including aldo-keto reductase family 1, member B10 (AKR1B10), were identified as SCC-specific genes. AKR1B10 was further examined by immunohistochemical analysis of 101 non-small cell lung carcinomas (NSCLC) and its overexpression was observed in 27 of 32 (84.4%) SCCs and 19 of 65 (29.2%) adenocarcinomas. Multiple regression analysis showed that smoking was an independent variable responsible for AKR1B10 overexpression in NSCLCs (P < 0.01) and adenocarcinomas (P < 0.01). AKR1B10 staining was occasionally observed even in squamous metaplasia, a precancerous lesion of SCC. CONCLUSION: AKR1B10 was overexpressed in most cases with SCC, which is closely associated with smoking, and many adenocarcinoma cases of smokers. These results suggest that AKR1B10 is a potential diagnostic marker specific to smokers' NSCLCs and might be involved in tobacco-related carcinogenesis. 相似文献