全文获取类型
收费全文 | 1447篇 |
免费 | 71篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 72篇 |
妇产科学 | 14篇 |
基础医学 | 191篇 |
口腔科学 | 26篇 |
临床医学 | 191篇 |
内科学 | 317篇 |
皮肤病学 | 67篇 |
神经病学 | 38篇 |
特种医学 | 306篇 |
外科学 | 96篇 |
综合类 | 28篇 |
预防医学 | 72篇 |
眼科学 | 22篇 |
药学 | 74篇 |
中国医学 | 2篇 |
肿瘤学 | 57篇 |
出版年
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 12篇 |
2018年 | 21篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 25篇 |
2013年 | 53篇 |
2012年 | 33篇 |
2011年 | 24篇 |
2010年 | 47篇 |
2009年 | 68篇 |
2008年 | 26篇 |
2007年 | 63篇 |
2006年 | 37篇 |
2005年 | 30篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 22篇 |
2000年 | 24篇 |
1999年 | 31篇 |
1998年 | 78篇 |
1997年 | 82篇 |
1996年 | 101篇 |
1995年 | 62篇 |
1994年 | 60篇 |
1993年 | 54篇 |
1992年 | 26篇 |
1991年 | 21篇 |
1990年 | 27篇 |
1989年 | 44篇 |
1988年 | 43篇 |
1987年 | 39篇 |
1986年 | 51篇 |
1985年 | 44篇 |
1984年 | 10篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 14篇 |
1938年 | 9篇 |
1937年 | 6篇 |
1933年 | 15篇 |
排序方式: 共有1574条查询结果,搜索用时 859 毫秒
91.
Bianchi J Douglas WS Dawe RS Lucke TW Loney M McEvoy M Urcelay M 《Journal of wound care》2000,9(3):109-112
The objective of the study was to investigate pulse oximetry as a guide to assessing patients with leg ulcers before treatment. Graduated elastic compression is the treatment of choice for uncomplicated venous leg ulcers, but is contra-indicated in patients with significant arterial disease. The standard assessment of arterial insufficiency by Doppler ultrasound ankle branchial pressure index (ABPI) has shortcomings which prompted this investigation of pulse oximetry as a possible additional, or alternative, method of assessment of patients with leg ulcers, prior to treatment with compression. The study, carried out on a population of patients attending hospital leg ulcer clinics, was designed to evaluate pulse oximetry assessment in the selection and monitoring of patients with venous leg ulceration leading to a prospective controlled study of ulcer healing in groups of patients with reduced and normal ABPI, selected for compression therapy by pulse oximetry criteria. Outcome measurement required follow-up of patients selected for compression therapy by pulse oximetry to record time to healing and rate of healing of leg ulcers. Results from the study show a fair correlation between the toe-finger oximetry index (TFOI) and Doppler ABPI. There is no difference between ulcer healing in patients with reduced and normal ABPI selected for treatment on the basis of pulse oximetry maximum compression pressure (MCP). In conclusion, pulse oximetry is an aid to the selection of patients who will benefit from compression therapy, but would be excluded on the basis of Doppler ABPI. 相似文献
92.
Cytogenetic and molecular genetic analysis of tumorigenic human bronchial epithelial cells induced by radon alpha particles 总被引:4,自引:1,他引:4
To establish a cell culture model for lung carcinogenesis, independent
populations of the human papillomavirus 18-immortalized human bronchial
epithelial cell line BEP2D were treated with high linear energy transfer
radon-simulated alpha-particles, expanded and xenotransplanted into Nu/Nu
mice. Six independent cell lines were established from tumors that
developed from three separate radiation treatments as follows: treatment
(Tx) 1 (30 cGy--two doses), H2BT, Tx 2 (30 cGy-- single dose), R30T1L,
R30T2 and R30T3L, Tx 3 (30 cGy--single dose), H1ATN and H1ATBA1.
Cytogenetic analysis revealed common changes in all tumor lines: loss of
the Y chromosome (ch), one of three copies of ch8, one of three copies of
ch14, and one of two copies of ch4p16-pter and ch11p15-pter. Analysis of
polymerase chain reaction-amplified short tandem repeats of informative
loci confirmed the loss of chY in all lines and loss of heterozygosity
(LOH) at eight loci spanning the length of ch8 in all lines from Tx's 1 and
2. Our data support previous studies indicating the presence of tumor
suppressor genes on ch8. LOH also was confirmed on ch14 at locus D14S306 in
all cell lines from Tx 2 and in one of two lines from Tx 3. This region,
14q12-q13, may contain changes in one of the five known somatostatin
receptor genes (SSTR1). No LOH was detected at any of the informative loci
tested for on ch4 or ch11.
相似文献
93.
HM Goodyear JC Moore-Gillon EH Price VF Larcher MO Savage CB Wood 《Archives of disease in childhood》1993,69(2):229-231
Childhood tuberculosis is perceived by many as a disease of the past. Experience in a children's hospital serving a deprived population suggested that tuberculosis and other mycobacterial infections were not declining in clinical practice. Fifty three tuberculous and 11 atypical mycobacterial infections were identified between 1978 and 1992. There was no decline in tuberculosis and nine of the 11 atypical infections occurred in the last five years. Altogether 40% of cases of tuberculosis were in non-Asian children; 32% had arrived in the UK or visited family overseas in the previous year; and 38% had a history of tuberculosis contact, usually a close adult relative. Nationally, the previous decline in tuberculosis in all ages has reversed. In the local health districts in London's east end, childhood tuberculosis has also stopped declining and seems to be increasing. It is regrettable that BCG vaccination has been abolished by some districts in the UK, against current recommendations. Childhood tuberculosis is still common in the practice described here, including among children who do not fall into conventionally recognised high risk groups. Inner city dwellers and junior doctors are both highly mobile populations, adding to the risk that paediatricians, particularly those in training, may encounter tuberculosis with little or no previous experience of the condition. 相似文献
94.
95.
Hale JD; Valk PE; Watts JC; Kaufman L; Crooks LE; Higgins CB; Deconinck F 《Radiology》1985,157(3):727-733
Multisection, dual-echo magnetic resonance (MR) transaxial images of blood vessels contain both anatomic and qualitative information about flow. Even so, the images are produced as a series of two-dimensional tomographic sections from which full visualization of connected structures is difficult. A computer algorithm was developed that automatically detects flowing blood based on pixel intensity and calculated T2 and provides reconstructed views of vessels while analyzing and displaying flow characteristics. Images of abdominal vessels, aortic aneurysms, and the heart were encoded by flow and color to demonstrate depth. In addition, these data were reconstructed to derive a more accurate assessment of patency. With this technique, transaxial images can be used to analyze flow patterns, determine patent areas, and visualize all levels of vessels in a single image. 相似文献
96.
IT services in a completely digitized radiological department: value and benefit of an in-house departmental IT group 总被引:1,自引:1,他引:0
Treitl M Wirth S Lucke A Villain S Rieger J Pfeifer KJ Reiser M 《European radiology》2005,15(7):1485-1492
To analyze the benefit of a departmental IT group in comparison to support by hospital IT groups or system manufacturers in a completely digitized radiological department. The departmental IT group comprises a fulltime IT specialist, two student assistants and four clinical employees participating 1 day/week. For 18 months IT problems were quantified and specified according to urgency, responsibility and affected system by use of an intranet-based reporting system. For each IT service provider the performance and duration of problem solution was evaluated. In 18 months 3,234 IT problems emerged. 88.7% were solved by the departmental IT group. In 474 cases (14.7%) a solution within 2 h was required. The departmental IT group solved 35.8% within 30 min, system manufacturers needed 18 h 38 min in mean. The departmental IT group solved 90.2% of the problems within a time limit. System manufacturers met the limit in 60.1% with a mean duration of 7 days 21 h. In 6.7% of the cases, support by system manufacturers was indispensable. A considerable proportion of IT problems in completely digitized radiological departments can be solved by a departmental IT group, providing a fast and cost-efficient first-level IT support with effective prevention of major breaks in the workflow. In a small number of cases support by system manufacturers remains necessary.This work was orally presented on ECR 2004 in Vienna. 相似文献
97.
Carcinoma of the papilla of Vater. A review of fifty-seven cases 总被引:3,自引:0,他引:3
Fifty-seven cases of carcinoma of the papilla of Vater are reviewed. Clinical and pathologic features as well as results of various surgical treatments are summarized. The Whipple operation may be the operation of choice for cancer of the papilla of Vater, offering a chance for cure and obviating further surgery. 相似文献
98.
Herbert Brown was Consultant Dermatologist to the Victoria Infirmary, Glasgow during the first half of the 20th Century. He was a keen amateur photographer, and his large archive of photographs illustrates comprehensively the work of a clinical dermatologist in that era. 相似文献
99.
OBJECTIVE: To determine whether children's food consumption is increased by the size of the group of children in which they are eating. DESIGN: Crossover study. SETTING: University based preschool. PARTICIPANTS: 54 children, aged 2.5-6.5 years. INTERVENTIONS: Each child ate a standardised snack in a group of three children, and in a group of nine children. MAIN OUTCOME MEASURES: Amount each individual child consumed, in grams. RESULTS: Amount eaten and snack duration were correlated (r = 0.71). The association between group size and amount eaten differed in the short (<11.4 min) versus the long (> or =11.4 min) snacks (p = 0.02 for the interaction between group size and snack duration). During short snacks, there was no effect of group size on amount eaten (16.7 (SD 11) g eaten in small groups vs 15.1 (6.6) g eaten in large groups, p = 0.42). During long snacks, large group size increased the amount eaten (34.5 (16) vs 26.5 (13.8), p = 0.02). The group size effect was partially explained by a shorter latency to begin eating, a faster eating rate and reduced social interaction in larger groups. CONCLUSIONS: Children consumed 30% more food when eating in a group of nine children than when eating in a group of three children during longer snacks. Social facilitation of food consumption operates in preschool-aged children. The group size effect merits consideration in creating eating behaviour interventions. 相似文献
100.
Volumetric rendering of MR images 总被引:1,自引:0,他引:1
The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis. 相似文献