全文获取类型
收费全文 | 115332篇 |
免费 | 12438篇 |
国内免费 | 3727篇 |
专业分类
耳鼻咽喉 | 684篇 |
儿科学 | 2696篇 |
妇产科学 | 803篇 |
基础医学 | 8342篇 |
口腔科学 | 573篇 |
临床医学 | 15144篇 |
内科学 | 18966篇 |
皮肤病学 | 607篇 |
神经病学 | 4604篇 |
特种医学 | 4682篇 |
外国民族医学 | 98篇 |
外科学 | 10506篇 |
综合类 | 22412篇 |
现状与发展 | 12篇 |
预防医学 | 6863篇 |
眼科学 | 996篇 |
药学 | 10885篇 |
138篇 | |
中国医学 | 6813篇 |
肿瘤学 | 15673篇 |
出版年
2024年 | 516篇 |
2023年 | 2112篇 |
2022年 | 4319篇 |
2021年 | 5992篇 |
2020年 | 5623篇 |
2019年 | 4511篇 |
2018年 | 4082篇 |
2017年 | 4916篇 |
2016年 | 5105篇 |
2015年 | 4863篇 |
2014年 | 7973篇 |
2013年 | 7881篇 |
2012年 | 6862篇 |
2011年 | 7246篇 |
2010年 | 5873篇 |
2009年 | 5407篇 |
2008年 | 5432篇 |
2007年 | 5874篇 |
2006年 | 5173篇 |
2005年 | 4494篇 |
2004年 | 3620篇 |
2003年 | 3081篇 |
2002年 | 2583篇 |
2001年 | 2389篇 |
2000年 | 1930篇 |
1999年 | 1586篇 |
1998年 | 1336篇 |
1997年 | 1290篇 |
1996年 | 1113篇 |
1995年 | 1025篇 |
1994年 | 946篇 |
1993年 | 727篇 |
1992年 | 804篇 |
1991年 | 645篇 |
1990年 | 549篇 |
1989年 | 471篇 |
1988年 | 458篇 |
1987年 | 415篇 |
1986年 | 337篇 |
1985年 | 327篇 |
1984年 | 307篇 |
1983年 | 206篇 |
1982年 | 230篇 |
1981年 | 164篇 |
1980年 | 146篇 |
1979年 | 140篇 |
1978年 | 126篇 |
1977年 | 73篇 |
1976年 | 70篇 |
1975年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
11.
There is evidence that leukocyte contaminating red blood cells and platelet concentrates are responsible for refractoriness to platelet transfusions. The efficacy of a cotton-wool filter to remove leukocytes from red blood cells has been documented previously. The present study was designed to evaluate whether the cotton-wool filters can effectively remove leukocytes from platelet concentrates. Sixty pools of random-donor platelets and single-donor plateletpheresis products were filtered through a cotton-wool filter. The efficacy of filtration was determined by measuring the absolute numbers of leukocytes and platelets and subpopulations of mononuclear cells. The average platelet loss was 8% per pool of random platelets and 10% per plateletpheresis product. The average leukocyte removal was 99% from a pool of random platelets and plateletpheresis concentrates collected by CS-3000 and 90% from plateletpheresis concentrates harvested by single-stage COBE/IBM-2997. The filtration removed 100% of granulocytes, 95% of monocytes, 90% of B-lymphocytes, and 85% of T-lymphocytes. We conclude that filtration through a cotton-wool filter is an efficient and cost-effective method for preparation of leukocyte-poor platelets. 相似文献
12.
13.
14.
Geir Håland Kai-Håkon Carlsen Chandra Sekhar Devulapalli Morten Pettersen Petter Mowinckel Karin C. Lødrup Carlsen 《Pediatric allergy and immunology》2007,18(6):528-534
The aim of the study was to assess if lung function at birth predicts lung function at 2 yr and secondly, if lung function development was influenced by the common phenotypes of recurrent bronchial obstruction (rBO) or atopic eczema (AE) by 2 yr. Lung function was assessed at birth (n = 802) and at 2 yr within the prospective birth cohort study 'the Environment and Childhood Asthma Study' in Oslo. The 135 children with lung function measured at birth by tidal flow volume (TFV) loops and passive respiratory mechanics, who were included in a nested case-control study were reinvestigated at 2 yr with clinical examination, TFV loops (n = 90) (mean age 26.6 (3.7 s.d.) months), skin prick test and parental interview. Children were categorized into quartiles (lower, middle two, upper) according to time to peak tidal expiratory flow/total expiratory time (t(PTEF)/t(E)) at birth as well as clinical phenotype based on the presence of rBO and/or AE (ever) by 2 yr. The observed reduction in mean t(PTEF)/t(E) from birth to 2 yr within the quartiles, were not significantly different after controlling for 'regression to the mean'. t(PTEF)/t(E) at birth correlated significantly with t(PTEF)/t(E) at 2 yr, (r = 0.475, p < 0.001). Children with both rBO and AE by 2 yr had significantly lower t(PTEF)/t(E) at 2 yr (p = 0.002) and at birth (p = 0.027), compared with children with no rBO or AE. Clinical phenotype at 2 yr did not influence the change in t(PTEF)/t(E) from birth to 2 yr. This study demonstrates a clear tracking of lung function from birth, not influenced by rBO or AE by 2 yr. 相似文献
15.
Seiichi Saito Shunichi Namiki Kenji Numahata Makoto Satoh Shigeto Ishidoya Akihiro Ito Haruo Nakagawa Yasuhiro Kaiho Takehiko Sanada Atsushi Yamada Yoichi Arai 《International journal of urology》2007,14(2):133-139
PURPOSE: To determine the effect of an interposition nerve graft on sexual function after radical prostatectomy. METHODS: This study includes 64 patients, without hormonal therapy, who underwent a radical prostatectomy and intraoperative electrophysiological confirmation of cavernous nerve preservation. Twelve patients underwent a unilateral interposition sural nerve graft (UNG) for the resected neurovascular bundle. Twenty-one and 31 patients underwent bilateral nerve-sparing (BNS) and unilateral nerve-sparing (UNS) surgery without a nerve graft, respectively. As the age of patients was significantly younger in the UNG group than in the other groups, age-matched analysis also was conducted. Sexual function, evaluated by a self-administered questionnaire using the University of California Los Angeles-Prostate Cancer Index, was compared statistically among the three groups. RESULTS: In the age-matched analysis, the postoperative sexual function (SXF) score of the UNG group showed an intermediate level of recovery between those of the BNS and UNS groups at 12 months and reached the same level as the score at 12 months of the BNS group at 18 months postoperatively. The difference in the SXF score between the UNG and UNS groups began to appear after 6 months postoperatively and increased steadily with time. However, the background factors, such as the baseline SXF score, the usage rate of phosphodiesterase 5 inhibitors, and the rate of comorbidities were different between the UNG and UNS groups. CONCLUSIONS: The difference of the SXF score between the UNG and UNS groups increased with time after 6 months postoperatively. However, it might be difficult at present to attribute a better recovery of the SXF score to the nerve graft because of the difference in the background factors between the groups. 相似文献
16.
L. C. Scott G. K. Wright G. S. Rai A. N. Exton-Smith J. M. Gardiner 《International journal of geriatric psychiatry》1991,6(8):583-588
Memory performance of elderly patients in the early stages of Alzheimer's disease (DAT) was compared with that of elderly control subjects. In explicit tests of recognition memory, which involve conscious recollection, the DAT patients were grossly impaired. In implicit tests of anagram solution and wordstem completion, which do not require conscious recollection, the DAT patients were not impaired. These findings further support the idea that a separate memory system, episodic memory, underlies conscious recollection, that it is this system which is most commonly damaged in amnesia, and that memory systems not involving conscious recollection may be spared in the early stages of Alzheimer's disease. 相似文献
17.
18.
The urinary cyclic AMP response to bovine parathyroid hormone and urinary concentrating ability (max Uosm) after des-amino-D -arginine vasopressin were studies in nine volunteers and seven patients receiving long-term neuroleptic treatment. Max Uosm was lower in the patient group (770 ± 70 mosmol/kg) compared with the controls (948 ± 152 mosmol/kg) but the trend to a lower cAMP response to bovine PTH was not statistically significant. These results suggest that, although adenylate cyclase inhibition may contribute, other mechanisms are also important in the genesis of reduced uring concentrating ability in patients treated with psychotropic drugs. 相似文献
19.
The case of a 75-year-old man with three synchronous carcinomas of the lung (large cell carcinoma, adenocarcinoma, and small cell carcinoma) is reported. This is the eighth well-documented case report in the literature; however, our case is the first to be reported with the newly described histological combination. 相似文献
20.
Dr. J. Tajti MD PhD ; Dr. K. Sas MD ; Dr. D. Szok MD ; Dr. E. Vörös MD ; Dr. L. Vécsei MD DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache. 相似文献