全文获取类型
收费全文 | 7209篇 |
免费 | 533篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 224篇 |
妇产科学 | 147篇 |
基础医学 | 846篇 |
口腔科学 | 194篇 |
临床医学 | 846篇 |
内科学 | 1513篇 |
皮肤病学 | 100篇 |
神经病学 | 359篇 |
特种医学 | 308篇 |
外科学 | 988篇 |
综合类 | 191篇 |
预防医学 | 487篇 |
眼科学 | 109篇 |
药学 | 584篇 |
中国医学 | 17篇 |
肿瘤学 | 794篇 |
出版年
2023年 | 39篇 |
2022年 | 72篇 |
2021年 | 153篇 |
2020年 | 92篇 |
2019年 | 131篇 |
2018年 | 161篇 |
2017年 | 107篇 |
2016年 | 134篇 |
2015年 | 132篇 |
2014年 | 212篇 |
2013年 | 303篇 |
2012年 | 428篇 |
2011年 | 426篇 |
2010年 | 253篇 |
2009年 | 223篇 |
2008年 | 379篇 |
2007年 | 431篇 |
2006年 | 402篇 |
2005年 | 365篇 |
2004年 | 339篇 |
2003年 | 338篇 |
2002年 | 297篇 |
2001年 | 272篇 |
2000年 | 245篇 |
1999年 | 193篇 |
1998年 | 96篇 |
1997年 | 72篇 |
1996年 | 84篇 |
1995年 | 65篇 |
1994年 | 59篇 |
1993年 | 62篇 |
1992年 | 128篇 |
1991年 | 86篇 |
1990年 | 112篇 |
1989年 | 101篇 |
1988年 | 96篇 |
1987年 | 85篇 |
1986年 | 70篇 |
1985年 | 71篇 |
1984年 | 45篇 |
1983年 | 50篇 |
1982年 | 30篇 |
1981年 | 30篇 |
1980年 | 25篇 |
1979年 | 39篇 |
1978年 | 29篇 |
1977年 | 24篇 |
1975年 | 23篇 |
1974年 | 28篇 |
1971年 | 19篇 |
排序方式: 共有7781条查询结果,搜索用时 20 毫秒
11.
12.
C. W. Chow A. Poulos A. J. Fellenberg J. Christodoulou D. M. Danks 《Acta neuropathologica》1992,83(2):190-195
Summary Recognition of adrenal atrophy during a review of autopsy findings in two sisters who died at 8 months and 3 1/2 years prompted estimation of very long chain fatty acids, phytanic acid and pristanic acid on wet liver fixed in formalin for 12 years. These were shown to be markedly increased and defects in multiple peroxisomal functions and decrease in particulate catalase were shown in cultured fibroblasts, confirming an abnormality of peroxisomal biogenesis. The patients had presented with failure to thrive, recurrent diarrohea and vomiting, poor mental development, retinal pigmentation, blindness and in the older patient deafness, with only mild dysmorphic features. Autopsy in the older patient showed adrenal atrophy, cirrhosis, and foamy histiocytes in multiple organs. The brain showed no demyelination, little cytoarchitectural abnormality, occasional perivascular histiocytes in the grey matter and meninges and prominent Purkinje cells in the molecular layer of the cerebellum. In the younger patient the changes were very subtle in spite of the marked clinical similarity. Despite the young age at death the clinicopathological features are most suggestive of infantile Refsum disease. In many situations anatomical pathology can be very useful in the recognition and study of peroxisomal disorders. 相似文献
13.
A. Chan R. Shinde C. C. Chow C. S. Cockram R. Swaminathan 《Clinical endocrinology》1994,41(2):213-216
OBJECTIVE Thyrotoxic periodic paralysis (TPP) usually follows a heavy carbohydrate meal and this may be explained by hyperinsulinaemia stimulating Na+, K+ -ATPase activity. To clarify this the effect of glucose load on serum insulin concentration and platelet Na+, K+ -ATPase activity In thyrotoxic periodic paralysis (TPP) was examined. DESIGN In all subjects a standard 75-g glucose tolerance test was done and blood samples were taken at 0, 1 and 2 hours. SUBJECTS Twenty-five healthy controls (8 M and 17 F), 17 uncomplicated thyrotoxic patients (7M and 10 F), 15 TPP patients who presented with paralysis and 4 TPP patients after treatment with antithyrold drugs. MEASUREMENTS Plasma glucose was measured by the glucose oxidase method, serum insulin by radioimmunoassay and platelet Na+, K+ -ATPase by the release of phosphate from ATP. RESULTS TPP patients showed glucose intolerance (area under the curve (AUC) 16·5 ± 4·4 (mean ± SD) In TPP compared to 12·9 ± 4·5 In controls (P < 0·01) and hyperinsulinaemia (AUC 189·6 ±100·6 vs 98·5 ±53·4, P < 0·001). In uncomplicated thyrotoxicosis the results were similar to that in healthy controls. Platelet Na+, K+ -ATPase were significantly higher in thyrotoxic patients compared to controls and In TPP patients were even higher. Ingestion of glucose increased platelet Na+, K+ -ATPase in all groups. AUC for platelet Na+, K+ -ATPase in TPP patients were significantly higher than in uncomplicated thyrotoxicosis (601 ±99·3 vs 482 ± 109·4, P < 0·01) or healthy controls (320 ± 107·3). In the 4 TPP patients studied after antithyroid treatment the results were similar to healthy controls. CONCLUSION Patients with thyrotoxic periodic paralysis have hyperinsulinaemia and this is accompanied by higher Na+, K+-ATPase activity. 相似文献
14.
Cefazolin plus ceftazidime versus imipenem/cilastatin monotherapy for treatment of CAPD peritonitis--a randomized controlled trial. 总被引:2,自引:0,他引:2
Chi-Bon Leung Cheuk-Chun Szeto Kai-Ming Chow Bonnie Ching-Ha Kwan Angela Yee-Moon Wang Siu-Fai Lui Philip Kam-Tao Li 《Peritoneal dialysis international》2004,24(5):440-446
BACKGROUND: Peritonitis is a serious complication of peritoneal dialysis (PD). We studied the efficacy of imipenem/cilastatin monotherapy in the treatment of PD-related peritonitis. METHODS: We performed an open-label, randomized control study comparing imipenem/cilastatin monotherapy (treatment group) versus cefazolin plus ceftazidime (control group) in the treatment of PD peritonitis. The result was further compared to a historic group treated with cefazolin plus netilmycin. Outcome measures were primary response rate at day 10 and complete cure rate. RESULTS: We enrolled 51 patients in the treatment group, 51 in the control group, and identified 96 in the historic group. The primary response rate to the assigned antibiotics was 49.0%, 51.0%, and 49.0% for the treatment, control, and historic groups, respectively (p = 0.97). The primary response rate allowing for change in antibiotic was 82.4%, 90.2%, and 82.3%, respectively, for the three groups (p = 0.41). The complete cure rate was 72.5%, 80.4%, and 82.3%, respectively (p = 0.60). Tenckhoff catheter removal was needed in 6 cases in the treatment group, 6 cases in the control group, and 13 cases in the historic group (p = 0.90). CONCLUSIONS: We concluded that monotherapy of imipenem/cilastatin has similar efficacy compared to the two standard regimens of cefazolin plus ceftazidime or netilmycin in the treatment of PD peritonitis. 相似文献
15.
16.
Bone marrow fat content in relation to bone remodeling and serum chemistry in intact and ovariectomized dogs 总被引:6,自引:0,他引:6
R. Bruce Martin Ph.D. Betty D. Chow Paul A. Lucas 《Calcified tissue international》1990,46(3):189-194
Summary It was previously shown that 11 months after ovariectomy the volume fraction of trabecular bone in the spine and 11th rib
medullary canal of Beagle dogs (6 control, 9 ovariectomized) was significantly reduced. In this paper it is shown that these
changes are accompanied by increased marrow fat volume in the 11th rib (59.0±9.5% vs. 44.3 ±10.0%). Conversely, the volume
fraction of functional (hematopoietic) cells in the marrow was reduced by ovariectomy. Additionally, variations in marrow
fat volume were tested for correlation with 22 other variables pertinent to bone physiology. Marrow fat volume was significantly
positively correlated with serum osteocalcin, rib trabecular bone porosity, rib cross-sectional area, and gains in body weight.
It was negatively correlated with serum estrogen concentrations and the extent of rib trabecular surfaces labeled with tetracycline. 相似文献
17.
18.
Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when "set" or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist. 相似文献
19.
Long term variation in beam symmetry as a function of gantry angle for a computer-controlled linear accelerator 总被引:2,自引:0,他引:2
Testing computer-controlled linear accelerators for patient safety and proper patient dose delivery requires that certain beam characteristics be monitored over an extended period of time. Computer-controlled conformal radiation therapy using asymmetric collimator jaw settings necessitates stable symmetric treatment beams. Long term beam symmetry measurements have been performed on a Philips SL20 dual energy computer-controlled linear accelerator. Symmetry in both the radial and transverse axis of each x-ray beam was monitored for eight gantry positions. These measurements were undertaken to determine the effectiveness of the SL20 beam steering system during dose delivery of 50 monitor units (MU) per field. Evaluation of the data shows that careful beam steering setup procedures result in x-ray beams in which fluctuations in symmetry as a function of gantry angle are within +/- 1.5%. Day to day instabilities produce a total overall variation in beam symmetry on the order of +/- 2.0%. Results suggest the measurement of symmetry as a function of gantry position become a routine quality assurance procedure for this accelerator. 相似文献
20.
Xiao Y Zhang Wing Y Chan Bruce M Whitney Dai M Fan John H S Chow Yong Liu Enders K W Ng Sheung C S Chung 《Diagnostic molecular pathology》2002,11(3):135-139
Helicobacter pylori (HP) infection induces expression of IL-8 and IL-10 in benign gastric epithelium. This study compared the expression of cytokines in CD4+ and CD8+ lymphocyte subsets of peripheral blood lymphocytes (PBL), benign mucosal lymphocytes (ML), and tumor infiltrative lymphocytes (TIL) as well as in the benign and malignant epithelial cells of the same patient, with respect to the presence of HP infection, lymph node metastases, and tumor histologic type. The mRNA of the cytokines was measured by a semiquantitative RT-PCR method. The levels were ranked and compared using the Wilcoxon sign-ranked test. Compared with CD8+ ML, the CD8+ TIL expresses higher levels of IL-6 and IL-8 but lower level of IL-4 in patients with lymph node metastases. In patients with HP infection, expression of IL-8 and IL-10 was higher in the gastric carcinoma cells than in the benign epithelial cells while expression of IL-6 and IL-8 were higher in CD8+ TIL than CD8+ ML. Overexpression of IL-8 in HP associated gastric carcinomas suggested that they might have arisen from HP-infected epithelial cells. 相似文献