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   962篇
  免费   60篇
  国内免费   26篇
耳鼻咽喉   1篇
儿科学   53篇
妇产科学   10篇
基础医学   72篇
口腔科学   26篇
临床医学   76篇
内科学   320篇
皮肤病学   22篇
神经病学   26篇
特种医学   122篇
外科学   85篇
综合类   22篇
一般理论   1篇
预防医学   28篇
眼科学   9篇
药学   78篇
肿瘤学   97篇
  2023年   2篇
  2022年   6篇
  2021年   19篇
  2020年   10篇
  2019年   8篇
  2018年   21篇
  2017年   6篇
  2016年   12篇
  2015年   15篇
  2014年   16篇
  2013年   24篇
  2012年   32篇
  2011年   26篇
  2010年   14篇
  2009年   33篇
  2008年   32篇
  2007年   53篇
  2006年   35篇
  2005年   35篇
  2004年   15篇
  2003年   28篇
  2002年   18篇
  2001年   17篇
  2000年   21篇
  1999年   16篇
  1998年   45篇
  1997年   50篇
  1996年   57篇
  1995年   41篇
  1994年   34篇
  1993年   35篇
  1992年   23篇
  1991年   20篇
  1990年   28篇
  1989年   34篇
  1988年   28篇
  1987年   18篇
  1986年   19篇
  1985年   17篇
  1984年   12篇
  1983年   13篇
  1982年   8篇
  1981年   7篇
  1980年   5篇
  1979年   5篇
  1978年   2篇
  1977年   12篇
  1976年   6篇
  1975年   9篇
  1972年   2篇
排序方式: 共有1048条查询结果,搜索用时 15 毫秒
1.
A case study of multicentric reticulohistiocytosis is presented with extensive immunohistochemical studies of the infiltrate in both paraffin and cryostat sections. These studies showed that the cells are of monocyte/macrophage origin. B- and T-cell gene rearrangement analysis of multicentric reticulohistiocytosis was also performed and showed a germline configuration.  相似文献   
2.
The clinico-pathological features of nine urethral and urinary bladder polyps with prostate-type epithelium are described. The average age of the patients was 46 years. Three patients previously had cystoscopy and the lesion was not noticed on the initial examination. The commonest presentation in this series was haematuria, dysuria and frequency of micturition. One patient presented with postmicturition dribble and another with haemospermia. The polyps contained acini and papillae lined by prostate-type epithelium which was confirmed by immunohistochemical tests for prostate specific antigen and prostate acid phosphatase. In this series no age versus location relationship could be established. Symptoms resolved following resection or initial biopsy followed by fulguration. Recurrence is extremely rare.  相似文献   
3.
One-hundred and six male children aged 6-23 months with a history of acute watery diarrhoea of less than 72 h duration were randomized to receive either folic acid in a dose of 5 mg at 8-h intervals or placebo for 5 d. There were 54 children in the folic acid group and 52 in the placebo group. The admission characteristics were comparable between the two groups. No significant differences were observed in the intake of oral rehydration solution or stool output between the groups. The mean ± SD of total stool output (g kg−1) was 532 ± 476 vs 479 ± 354 and the duration (h) of diarrhoea was 108 ± 68 vs 103 ± 53 in the folic acid vs placebo group, respectively. The findings, therefore, should have a positive influence on preventing the inappropriate use of folic acid in acute diarrhoea.  相似文献   
4.
We studied the relationship between nutritional status and infection due to specific enteropathogens in young children with diarrhoea. Overall, 26% of the children were severely underweight, 27% were severely wasted and 19% were severely stunted. Children with Shigellae and V. cholerae O1 were significantly more severely underweight, wasted and stunted than those with rotavirus diarrhoea ( p < 0:0001). Our results indicate that an effective nutrition programme for young children might have greater impact on diarrhoeal illness caused by Shigella and V. cholerae than by rotavirus diarrhoea.  相似文献   
5.
The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony- stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c- derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid- specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling.  相似文献   
6.
Myelodysplastic syndromes: a scoring system with prognostic significance   总被引:7,自引:1,他引:7  
141 patients with MDS were classified according to the FAB criteria and followed up for a period of 4-192 months. It was recognized that patients with RAEBT had a uniformly poor prognosis. However, there was a wide variation in survival among the other subgroups. A score of 1 was assigned to each of the following presenting haematological features: bone marrow blasts greater than or equal to 5%, platelets less than or equal to 100 X 10(9)/l, neutrophils less than or equal to 2.5 X 10(9)/l and Hb less than or equal to 10.0 g/dl. Therefore the score for each patient ranged between 0 and 4. There were no statistically significant differences between those patients who scored 0 or 1, or between those who scored 2 and 3. Therefore patients were put into three groups: Group A (score 0 or 1), Group B (score 2 or 3), Group C (score 4). The differences in survival between each of the three groups are highly significant (P less than 0.00001). This system further separates patients with RA, RAS, RAEB into good and bad prognostic groups. This study also confirms that deaths due to cytopenias are more common than those due to transformation to AML. The use of this scoring system in conjunction with the FAB criteria for MDS should serve as a prognostic tool on which to base treatment.  相似文献   
7.
8.
9.
de Vries Reilingh  TS  van Geldere  D  Langenhorst  BLAM  de Jong  D  van der Wilt  GJ  van Goor  H  Bleichrodt  RP 《Hernia》2004,8(1):56-59
Polypropylene mesh is widely used for the reconstruction of incisional hernias that cannot be closed primarily. Several techniques have been advocated to implant the mesh. The objective of this study was to evaluate, retrospectively, early and late results of three different techniques, onlay, inlay, and underlay. The records of 53 consecutive patients with a large midline incisional hernia — 25 women and 28 men, mean age 60.4 (range 28–94) — were reviewed. Polypropylene mesh was implanted using the onlay technique in 13 patients, inlay in 23 patients, and underlay in 17 patients. Either the greater omentum or a polyglactin mesh was interponated between the mesh and the viscera. The records of these 53 patients were reviewed with respect to: size and cause of the hernia, pre- and postoperative mortality and morbidity, with special attention to wound complications. Patients were invited to attend the outpatient clinic at least 12 months after implantation of the mesh for physical examination of the abdominal wall. Postoperative complications occurred in 14 (26.4%) patients. The onlay technique had significantly more complications, as compared to both other techniques. Reherniation occurred in 15 (28.3%) patients. The reherniation rate of the inlay technique was significantly higher than after the underlay technique (44% vs 12%, P=0.03) and tended to be higher than the onlay technique (44% vs 23%, P=0.22). Repair of large midline incisional hernias with the use of a polypropylene mesh carries a high risk of complications and has a high reherniation rate. The underlay technique seems to be the better technique.  相似文献   
10.
T1G3 bladder cancer--indications for early cystectomy   总被引:1,自引:0,他引:1  
OBJECTIVES: To review our experience with early radical cystectomy in patients with T1G3 Transitional Cell Carcinoma of bladder (TCC). PATIENTS AND METHODS: Thirty patients, who underwent early radical cystectomy over a 10-year period for clinical stage T1G3 TCC bladder, were studied. Of these 21 (70%) had radical cystectomy without treatment with intravesical chemo/immunotherapy. The number of tumours, presence or absence of Carcinoma In-Situ (CIS) and the pathological stage of the cystectomy specimen were recorded in each patient. Disease specific survival was determined in the subgroups using Kaplan-Meier estimates. RESULTS: Seventeen patients underwent radical surgery for a single tumour without concomitant CIS (Group A). The other 13 had multiple tumours with or without concomitant CIS or a single tumour with CIS (Group B). The disease was upstaged after cystectomy in 1 (6%) patient in Group A compared to 7 (55%) in Group B, (p = 0.009). Nine (53%) had pT0 disease in Group A compared to 0% in Group B, (p = 0.0017). The 5-year cancer specific survival rates were 92% in Group A and 82% in Group B. CONCLUSIONS: In patients with multiple T1G3 tumours with or without associated CIS, or in those with single T1G3 tumour with associated CIS the incidence of the disease being already muscle invasive at the time of clinical diagnosis is 55%. Early radical cystectomy should be advocated in this group. Conversely, for a single T1G3 tumour without associated CIS, conservative bladder preserving strategy with immuno-chemotherapy and close surveillance is justified.  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