全文获取类型
收费全文 | 1695篇 |
免费 | 152篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 138篇 |
妇产科学 | 23篇 |
基础医学 | 190篇 |
口腔科学 | 58篇 |
临床医学 | 161篇 |
内科学 | 312篇 |
皮肤病学 | 80篇 |
神经病学 | 107篇 |
特种医学 | 235篇 |
外科学 | 102篇 |
综合类 | 59篇 |
一般理论 | 1篇 |
预防医学 | 161篇 |
眼科学 | 8篇 |
药学 | 89篇 |
肿瘤学 | 141篇 |
出版年
2022年 | 18篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 27篇 |
2017年 | 24篇 |
2016年 | 18篇 |
2015年 | 25篇 |
2014年 | 33篇 |
2013年 | 48篇 |
2012年 | 57篇 |
2011年 | 57篇 |
2010年 | 45篇 |
2009年 | 38篇 |
2008年 | 51篇 |
2007年 | 53篇 |
2006年 | 40篇 |
2005年 | 50篇 |
2004年 | 47篇 |
2003年 | 46篇 |
2002年 | 39篇 |
2001年 | 49篇 |
2000年 | 48篇 |
1999年 | 49篇 |
1998年 | 56篇 |
1997年 | 54篇 |
1996年 | 51篇 |
1995年 | 49篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 30篇 |
1991年 | 35篇 |
1990年 | 35篇 |
1989年 | 54篇 |
1988年 | 49篇 |
1987年 | 62篇 |
1986年 | 39篇 |
1985年 | 30篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 26篇 |
1980年 | 22篇 |
1979年 | 18篇 |
1978年 | 17篇 |
1977年 | 13篇 |
1976年 | 26篇 |
1975年 | 18篇 |
1973年 | 15篇 |
1968年 | 11篇 |
排序方式: 共有1869条查询结果,搜索用时 18 毫秒
1.
2.
BACKGROUND: Paediatric audiology services and screening programmes are currently under review. AIMS AND METHODS: To investigate current practice and performance of the school hearing screening programme (SHSP) by means of a questionnaire. RESULTS: SHSP was found to detect previously unrecognised hearing loss at low cost. Wide variation in practice was shown, and the majority of services had no computerised system for data collection. CONCLUSION: There is a need for nationally agreed protocols and quality assurance procedures. 相似文献
3.
4.
The long-term consequences for infants with problems of feeding and crying behavior remain unknown. The purpose of this research was to determine whether such children are later perceived by their parents as vulnerable and more often have behavior problems and have different personalities than children without problems in infancy. The implications of managing such problems by changing milk formulas is explored. Mothers of 379 infants were enrolled in the postpartum period. Information about problems of feeding and crying behavior was obtained at 4 months. Thirty-six percent of the infants had problems and the formula had been changed for 17%. At 3 1/2 years, 320 (84%) mothers completed a questionnaire. Children who had had problems were more often perceived as vulnerable (relative risk [RR] 1.86; 95% confidence interval [CI] 1.09, 3.19) and more often had behavior problems (RR 1.78; 95% CI 1.03, 3.07). There were no differences in personality. Children whose problems had been managed by changing milk formulas were more often perceived as vulnerable (RR 2.18; 95% CI 1.05, 4.53). Although allergies were reported significantly more often for those children who had had problems, there were no differences in the prevalence of asthma or eczema. Problems of feeding and crying behavior in early infancy and the way they are managed may have long-term implications for the child. 相似文献
5.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
6.
Yoshimitsu Kuroyanagi DR. ENG DR. SCI DR. MED ; Akihiko Shiraishi MD ; Yoshiteru Shirasaki MD ; Nobuaki Nakakita MD ; Yoshiaki Yasutomi MD ; Yasuo Takano MD ; Nobuyuki Shioya MD FACS 《Wound repair and regeneration》1994,2(2):122-129
A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved. 相似文献
7.
DR Foster 《Journal of Medical Imaging and Radiation Oncology》1995,39(4):399-400
The use of self-expanding prostheses in the management of malignant oesophageal strictures has become well established. The majority of benign peptic oesophageal strictures can be successfully managed using endoscopic or fluoroscopically guided balloon oesophageal dilatation combined with long-term drug therapy, particularly using proton pumper inhibitors. Although endoscopic oesophageal dilatation can be performed on an outpatient basis, it requires repeated hospital visits. There is a small risk of oesophageal perforation whilst cardio-respiratory complications may be encountered during the use of intravenous sedation in an elderly population. The use of a self-expanding Strecker stent in a 98 year old woman with a benign oesophageal stricture is described. 相似文献
8.
In 260 asbestos-exposed individuals evaluated by means of computed tomography (CT), 43 unsuspected pulmonary masses were found in 27 individuals. The masses included fissural pleural plaques (n = 10), dense fibrotic bands (n = 3), round atelectasis (n = 11), carcinomas (n = 3), and other presumed benign masses (n = 16). The most helpful features in the diagnosis of rounded atelectasis with CT were (a) contiguity to areas of diffuse pleural thickening, (b) a lentiform or wedge-shaped outline, (c) evidence of volume loss in the adjacent lung, and (d) a characteristic "comet tail" of vessels and bronchi sweeping into the margins of the mass. Less advanced areas of focal atelectasis had fewer classic features. Intrafissural pleural plaques were readily identified with high-resolution CT. In asbestos-related masses, the demonstration of stability over time is necessary. Careful interpretation of CT and high-resolution CT features and close surveillance can obviate the need for biopsy in the majority of instances. 相似文献
9.
New epidemiologic evidence confirming that bias does not explain the aspirin/Reye's syndrome association 总被引:1,自引:0,他引:1
B W Forsyth R I Horwitz D Acampora E D Shapiro C M Viscoli A R Feinstein R Henner N B Holabird B A Jones A D Karabelas 《JAMA》1989,261(17):2517-2524
To determine the validity of the aspirin/Reye's syndrome association, we developed an epidemiologic investigation to assess the effects of five potential sources of bias. A case-control study incorporated procedures to avoid temporal precedence and susceptibility bias. These included classifying cases as having monophasic or biphasic patterns of illness and matching for severity of symptoms at zero-time. To evaluate the effect of a potential recall bias, an "alternate-condition" control group was enrolled. A medical record review study was conducted to assess the potential for diagnostic bias, and a blanket surveillance of all hospitals in a region was conducted to evaluate reporting bias. Twenty-four case subjects and 48 matched controls were enrolled. Eight-eight percent of case subjects and only 17% of controls had received aspirin prior to the onset of Reye's syndrome (matched odds ratio, 35; 95% confidence interval, 4.2 to 288). Further analyses demonstrated that the association could not be attributed to the five potential sources of bias. 相似文献
10.