首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   56577篇
  免费   2699篇
  国内免费   179篇
耳鼻咽喉   734篇
儿科学   1705篇
妇产科学   1546篇
基础医学   7630篇
口腔科学   2498篇
临床医学   4755篇
内科学   12608篇
皮肤病学   1163篇
神经病学   4778篇
特种医学   1580篇
外科学   6796篇
综合类   286篇
一般理论   22篇
预防医学   5404篇
眼科学   1067篇
药学   3955篇
中国医学   259篇
肿瘤学   2669篇
  2023年   461篇
  2022年   531篇
  2021年   1365篇
  2020年   808篇
  2019年   1275篇
  2018年   1990篇
  2017年   1338篇
  2016年   1399篇
  2015年   1621篇
  2014年   1884篇
  2013年   2555篇
  2012年   4127篇
  2011年   4333篇
  2010年   2093篇
  2009年   1703篇
  2008年   3412篇
  2007年   3604篇
  2006年   3310篇
  2005年   3316篇
  2004年   2974篇
  2003年   2833篇
  2002年   2668篇
  2001年   1132篇
  2000年   1178篇
  1999年   962篇
  1998年   305篇
  1997年   223篇
  1996年   204篇
  1995年   203篇
  1994年   167篇
  1993年   144篇
  1992年   545篇
  1991年   441篇
  1990年   371篇
  1989年   398篇
  1988年   313篇
  1987年   325篇
  1986年   297篇
  1985年   275篇
  1984年   191篇
  1983年   161篇
  1979年   153篇
  1978年   110篇
  1977年   111篇
  1976年   95篇
  1975年   118篇
  1974年   139篇
  1973年   109篇
  1972年   97篇
  1969年   94篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Primary pregnancy in the liver. A case report   总被引:1,自引:0,他引:1  
A case of intra-hepatic pregnancy is reported. The patient was 32 years old and presented with an acute intra-abdominal hemorrhage. At surgery a spongy 3 x 2 x 1.5 cm mass was removed from the right liver lobe. Microscopically, well developed chorionic villi appeared invading the liver tissue. The patient had a relatively uneventful recovery.  相似文献   
82.
We investigated the expression kinetics of several cytokines in trigeminal ganglia (TG) and in brains of BALB/c mice during the course of ocular herpes simplex virus type 1 (HSV-1) infection. All mice recovered from the infection within 2 weeks. The quantitative rapid real-time RT-PCR method was used to analyze interleukin-4 (IL-4), interferon-gamma (IFN-gamma), IL-12p35, IL-12p40, and the recently described IL-23 (p19) mRNA in TG, brain, and splenocyte samples. In TG, we found elevated expression of mRNA for IL-23 (p19) from early acute infection (day 3) to the beginning of the latent phase (day 14). The increase was not detected in brain or in the spleen. IL-4 expression occurred in both TG and brain from the beginning of the experiment to the latent phase. During the latent phase (days 14 and 31), IL-4 expression was significantly elevated in the brain when compared with the uninfected controls (p < 0.05). Considerable expression of IFN-gamma mRNA was detected in TG of mice during acute HSV-1 infection. The expression of IL-23 was detected also in the brains of the mice, even though no significant changes were found during the acute HSV-1 infection. This is, to our knowledge, the first report to show elevated expression of IL-23 (p19) mRNA (p < 0.05) during viral infection in TG of mice.  相似文献   
83.
84.
25 synovial sarcomas in patients with various duration of life were studied electron-microscopically. Quantitative correlation between dark and clear tumour cells is the most informative prognostic index in patients operated on because of these sarcomas: the more numerous are dark cells in the tumour, the worse is the prognosis. The appearance of intermediate filaments in the cytoplasm of epithelioid tumour cells and the presence of secretory material in the intercellular spaces are the sign of a less favourable prognosis.  相似文献   
85.
Between November 1984 and January 1994 in our department, a total of 2500 patients were treated with totally absorbable internal fixation devices. We studied these patients and analyzed results with regard to the volume of the absorbable implants and the development of wound infection. Of the 2500 patients 2044 were trauma patients and 456 were operated on for orthopedic disease. In 1466 patients treated with implants made of self-reinforced polyglycolic acid (SR-PGA) only, the patients who developed wound infection had a higher implant volume (P=0.07) than those who did not; this difference was close to statistical significance. In the 446 patients who received only implants made of self-reinforced poly-l-lactic acid (SR-PLLA), the 5 who developed wound infection had a mean implant volume more than three times that of the non-infected patients (P=0.01). We found that in the patients treated with the earlier SR-PGA implants, which contained a green staining material, there was no correlation between implant volume and incidence of wound infections. On the other hand, both the non-stained SR-PGA implants, which have been in clinical use since 1989, and the SR-PLLA implants, seem to be more predictable in terms of wound infections. We believe that this difference, is largely due to the lower level of tissue reactions with these newer implants.  相似文献   
86.
Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise99mTc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.  相似文献   
87.
Altogether twenty-six elderly subjects (aged 65-74 years) with persistent impaired glucose tolerance (World Health Organization (1985) criteria) identified in a population-based study, were randomly treated either with chromium-rich yeast (160 micrograms Cr/d) or with placebo for 6 months. The 24 h urinary Cr increased from 0.13 (SE 0.03) to 0.40 (SE 0.06) micrograms/d in the Cr group (n 13) but no change was found in the placebo group (n 11) (0.13 (SE 0.02) v. 0.11 (SE 0.02) micrograms/d). No significant change was observed in the oral glucose tolerance test (glucose dose 75 g; 0, 1 and 2 h blood glucose respectively): 5.3 (SE 0.1), 9.3 (SE 0.3), 8.2 (SE 0.3) mmol/l v. 5.0 (SE 0.1), 8.5 (SE 0.4), 7.3(SE 0.5) mmol/l in the Cr group; 4.9 (SE 0.2), 9.2 (SE 0.6), 8.1 (SE 0.3) mmol/l v. 4.8 (SE 0.2), 8.5 (SE 0.5), 7.0 (SE 0.6) mmol/l in the placebo group (baseline v. 6 months). Glycosylated haemoglobin, plasma insulin, C-peptide and apolipoprotein A1 and B levels remained unchanged, and no improvement was seen in serum total cholesterol (6.2 (SE 0.3) v. 6.4 (SE 0.3) mmol/l for the Cr group, 6.2 (SE 0.4) v. 6.5 (SE 0.3) mmol/l for the placebo group), high-density-lipoprotein-cholesterol (1.1 (SE 0.1) v. 1.2 (SE 0.1) mmol/l for the Cr group, 1.0 (SE 0.1) v. 1.1 (SE 0.1) mmol/l for the placebo group) or triacylglycerols (2.5 (SE 0.4) v. 2.0 (SE 0.4) mmol/l for the Cr group, 2.4 (SE 0.2) v. 2.5 (SE 0.2) mmol/l for the placebo group). The present results indicate that Cr supplementation does not improve glucose tolerance or serum lipid levels in elderly subjects with stable impaired glucose tolerance.  相似文献   
88.
Detectable TNF levels in sera 33% of patients with sepsis following pancreatitis have been found. No correlation was observed between serum TNF concentration and the severity of illness. However, monocytes and granulocytes of septic patients exerted higher TNF-mediated cytotoxicity than leukocytes of normal blood donors. The in vitro TNF-producing capacity was also higher in the patients in the study group, and it decreased only before fatal outcoming of sepsis. Our results suggest that determination of the TNF-producing capacity of leukocytes might be more informative than measurement of the serum TNF level in the evaluation of the severity or prognosis of sepsis.  相似文献   
89.
The authors present the results of hip arthroplasty of 67 patients treated after failed internal fixation of the osteoporotic, trochanteric fractures of the femur, which were primary stabilised with angular plate AO in 39 patients and with dynamic hip screw (DHS) in 28 patients. In the discussed material 16 persons were male and 51 female, in the age between 51 and 83 years old. According to the Evans classification in 4 cases we diagnosed type I of fracture, in 10--type II, 31--type III and in 22--type IV. Hip arthroplasty was made from the 3rd to the 39th week after primary fixation of the fracture. In 42 patients we made total hip arthroplasty, in 14 cases Austin-Moore hemiarthroplasty, and in 11 patients bipolar arthroplasty. According to the Postel and Merle d'Aubigne classification there were obtained 29 very good, 21 good and 17 satisfactory results.  相似文献   
90.
A wide variety of biological and alloplastic injectable biomaterials are available for soft tissue augmentation, but the ideal material has not yet been discovered. Biological materials such as collagen and hyaluronan yield temporary results, while injectable alloplasts are apt to cause varying degrees of foreign body reactions that may result in lumps and chronic inflammation.We present two cases (one is the first filed case in the world) of migratory subcutaneous inflammatory masses secondary to injection of acrylic hydrogel (DermaLive), which is an alloplastic biomaterial recently introduced into the market in Europe. Histology revealed foreign body reaction to acrylic hydrogel with granuloma formation containing multinucleated giant cells. Following this, further reports on complications have been reported elsewhere in Europe. The use and development of injectable materials, as well as alternative methods and future directions are reviewed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号