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   512篇
  免费   30篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   9篇
基础医学   63篇
口腔科学   10篇
临床医学   65篇
内科学   107篇
皮肤病学   11篇
神经病学   14篇
特种医学   17篇
外科学   59篇
综合类   21篇
预防医学   29篇
眼科学   3篇
药学   44篇
中国医学   1篇
肿瘤学   80篇
  2023年   4篇
  2022年   6篇
  2021年   21篇
  2020年   11篇
  2019年   11篇
  2018年   9篇
  2017年   6篇
  2016年   16篇
  2015年   18篇
  2014年   27篇
  2013年   17篇
  2012年   29篇
  2011年   46篇
  2010年   14篇
  2009年   26篇
  2008年   33篇
  2007年   36篇
  2006年   36篇
  2005年   36篇
  2004年   32篇
  2003年   24篇
  2002年   28篇
  2001年   1篇
  2000年   1篇
  1999年   3篇
  1998年   5篇
  1997年   6篇
  1996年   7篇
  1995年   6篇
  1994年   4篇
  1993年   3篇
  1992年   2篇
  1991年   6篇
  1987年   3篇
  1986年   5篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1978年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有547条查询结果,搜索用时 0 毫秒
51.
A convenient one step synthesis of chlorotrifluoroalkyl olefins starting from aldehydes was developed. The stable reagent 2-((1-chloro-2,2,2-trifluoroethyl)sulfonyl)benzothiazole was prepared from readily available benzothiazole-2-thiol and halothane. This method comprises using stable 2-((1-chloro-2,2,2-trifluoroethyl)sulfonyl)benzothiazole according to the Julia procedure and presents new opportunities for the synthesis of trifluoroalkylidene derivatives.

A convenient one step synthesis of chlorotrifluoroalkyl olefins starting from aldehydes was developed.  相似文献   
52.
Human herpesvirus (HHV)--6 infections are ubiquitous, but infection or reactivation under immunocompromised conditions, such as bone marrow or solid organ transplantation, can often result in serious clinical manifestations. Two HHV-6 subtypes are known. Most primary HHV-6 infections are caused by subtype 6B, but little information is available about the prevalence, distribution, and clinical divergence of 6A and 6B. To study this, we have developed a highly sensitive and specific real-time polymerase chain reaction (PCR) assay that can detect, quantitate, and reliably differentiate HHV-6A and -6B in clinical specimens. Exploiting a single-base variation in the DNA polymerase gene of these respective subtypes, we used melting curve analysis for subtype discrimination. Moreover, this assay's ability to discriminate HHV-6 subtypes was confirmed by PCR/restriction fragment length polymorphism analysis of the HHV-6 large tegument protein gene and PCR amplicon size-discrimination analysis of the HHV-6 immediate-early gene. Using this assay, we present our findings about the prevalence and distribution of these subtypes in bone marrow transplant patients. Of 803 plasma specimens tested from 353 patients, 136 specimens (17%) from 60 patients were determined to be HHV-6 positive. We analyzed these HHV-6--positive patients for subtype identification by using our newly developed assay and determined that 58 patients (97%) were HHV-6B positive and 2 patients (3%) were HHV-6A positive. No patient was coinfected with both subtypes. This assay can be a sensitive, genotype-specific, rapid method to reliably diagnose life-threatening HHV-6 infections in immunocompromised patients and can be useful in guiding and monitoring specific therapy.  相似文献   
53.
A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl3 carrier with carrier added [32P]H3PO4 in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1–10 μm as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation.  相似文献   
54.
55.
Fcgamma receptor-mediated phagocytosis is a model for the study of immunoreceptor (immunoreceptor tyrosine-based activation motif [ITAM]) signaling and involves the activation of protein tyrosine kinases, protein tyrosine phosphatases, and downstream effectors including phosphatidylinositol-3 (PI-3) kinase. Relatively little is known of the role of lipid phosphatases in the control of ITAM signaling and inflammation. A heterologous COS7 cell system was used to examine the roles played by PI-3 kinase and the dual-specificity phosphatase, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), in the signal transduction pathway leading to Fcgamma receptor IIA-mediated phagocytosis and the activation of Rac. The expression of wildtype PTEN completely abrogated the phagocytosis of immunoglobulin-G-sensitized sheep red blood cells, as compared with the catalytically inactive mutant of PTEN, which had no effect. This is the first direct evidence that PTEN, an inositol 3' phosphatase, regulates Fcgamma receptor-mediated phagocytosis, an ITAM-based signaling event. The data suggest that PTEN exerts control over phagocytosis potentially by controlling the downstream conversion of guanosine diphosphate-Rac to guanosine triphosphate-Rac following ITAM stimulation.  相似文献   
56.
Visual inspection after acetic acid application (VIA) and human papillomavirus (HPV) detection tests have been recommended to screen women for cervical cancer in low and middle income countries. A demonstration project in rural India screened 39,740 women with both the tests to compare their accuracies in real population setting. The project also evaluated the model of screening women in the existing primary health care facilities, evaluating the screen positive women with colposcopy (and biopsy) in the same setup and recalling the women diagnosed to have disease for treatment at tertiary center. Accuracy of VIA and HPV test used sequentially was also studied. VIA was performed by trained health workers and Hybrid Capture II (HC II) assay was used for oncogenic HPV detection. Test positivity was 7.1% for VIA and 4.7% for HC II. Detection rate of CIN 3+ disease was significantly higher with HC II than VIA. Sensitivities of VIA and HC II to detect 162 histology proved CIN 3+ lesions were 67.9 and 91.2%, respectively after adjusting for verification bias. Specificity for the same disease outcome and verification bias correction was 93.2% for VIA and 96.9% for HC II. Triaging of VIA positive women with HPV test would have considerably improved the positive predictive value (4.0 to 37.5% to detect CIN 3+) without significant drop in sensitivity. All VIA positive women and 74.0% of HC II positive women had colposcopy. There was high compliance to treatment and significant stage‐shift of the screen‐detected cancers towards more early stage.  相似文献   
57.
58.
A study was conducted to evaluate the potential of autologous bone marrow-derived cells in comparison with buffy coat of autologous blood for rapid cutaneous wound healing in rabbit model. Three square full-thickness skin excisional wounds were created in 15 selected experimental animals (rabbit) divided randomly into three groups. The wound was treated with autologous bone marrow cells in plasma (group 1), buffy coat of blood in plasma (group 2) and autologous plasma as control (group 3). Wounds were observed for 30 days for granulation tissue formation, biochemical, histomorphological and histochemical evaluation. In this study, granulation tissue appeared significantly lesser in wounds of group 3 animals followed by group 2 and 1 animals. Neovascularisation, granulation tissue formation, denser, thicker and better arranged collagen fibres, reticulin fibres and elastin fibres formation was more in group 1 as compared with other groups. It was concluded that the application of bone marrow-derived nucleated cells into the wound margins resulted in early and significantly faster rate of complete healing as compared with buffy coat of autologous blood and autologous plasma (control). This approach may be beneficial in various surface wounds that heal at a slower rate and recommended for healing of various complicated wound in future.  相似文献   
59.

Purpose

Various surgical modalities have been used in the surgical management of oral submucous fibrosis with variable results. This prospective study evaluates the efficacy of nasolabial flap in the reconstruction of fibrotomy defect in surgical treatment of oral submucous fibrosis in terms of functional and esthetic outcomes.

Material and method

In this prospective study, we treated 20 patients of oral submucous fibrosis surgically. The surgical protocol was consisting of bilateral fibrotomy, temporal myotomy, and coronoidotomy or coronoidectomy followed by reconstruction of fibrotomy defect with bilateral extended nasolabial flaps. All patients were prescribed with nutritional supplements and antioxidants. Vigorous mouth opening exercise was made compulsory for every patient. Preoperative and postoperative evaluation was done for interincisal mouth opening, function of mastication, and cosmetic results. Patient’s regular follow-up was done for 2 years.

Results

Postoperatively, we noted excellent increase in the interincisal mouth opening relieving trismus. Patient’s ability to chew solid food was increased significantly. Extraoral scar was minimal and well accepted by all the patients. There was no morbidity of the donor site. There was no injury to the facial nerve in all cases. The only drawback was intraoral hair growth which went on reducing with mucosalization of the graft tissue.

Conclusion

Random pattern nasolabial flap is a very good option for intraoral reconstruction of fibrotomy defect in surgical treatment of oral submucous fibrosis with excellent functional and cosmetic results with minimal complications.
  相似文献   
60.
p63 regulates commitment to the prostate cell lineage   总被引:9,自引:0,他引:9       下载免费PDF全文
Molecular mechanisms underlying prostate and urothelial development remain unclear. This situation presents major limitations in identifying the cell type(s) and molecular events involved in the development of prostate and bladder cancer. It has been shown that mice lacking the basal cell marker p63 present several epithelial defects, including epidermis and prostate buds agenesis and urothelial abnormalities. Here, we use the p63-/- mouse as a tool to define cell lineages in the prostate epithelium and urothelium. By complementing p63-/- blastocysts with p63+/+ beta-galactosidase (beta-gal)-positive ES cells, we show that secretory cells of the prostate originate from p63-positive basal progenitor cells. Importantly, our urogenital sinus transplantation studies demonstrate that p63 prevents intestinal differentiation of the urogenital sinus endoderm and is therefore required to maintain commitment to the prostate cell lineage. Finally, in contrast with the prostate findings, analysis of the urothelium from rescued p63-/- chimeras shows that umbrella (superficial) cells can develop and be maintained independently from p63-positive basal and intermediate cells.  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