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   760篇
  免费   82篇
  国内免费   1篇
耳鼻咽喉   9篇
儿科学   32篇
妇产科学   8篇
基础医学   145篇
口腔科学   12篇
临床医学   78篇
内科学   127篇
皮肤病学   35篇
神经病学   66篇
特种医学   21篇
外科学   112篇
综合类   11篇
预防医学   26篇
眼科学   13篇
药学   81篇
中国医学   6篇
肿瘤学   61篇
  2023年   5篇
  2022年   2篇
  2021年   25篇
  2020年   27篇
  2019年   33篇
  2018年   28篇
  2017年   22篇
  2016年   31篇
  2015年   30篇
  2014年   43篇
  2013年   36篇
  2012年   59篇
  2011年   50篇
  2010年   39篇
  2009年   33篇
  2008年   47篇
  2007年   46篇
  2006年   53篇
  2005年   26篇
  2004年   34篇
  2003年   18篇
  2002年   30篇
  2001年   16篇
  2000年   13篇
  1999年   8篇
  1998年   3篇
  1997年   3篇
  1996年   9篇
  1995年   5篇
  1994年   2篇
  1992年   4篇
  1991年   5篇
  1990年   8篇
  1989年   10篇
  1988年   4篇
  1986年   6篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1979年   2篇
  1978年   3篇
  1977年   2篇
  1974年   3篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
  1968年   1篇
  1965年   1篇
  1962年   1篇
  1961年   1篇
排序方式: 共有843条查询结果,搜索用时 31 毫秒
1.
Brachial plexus palsy is a surgically manageable condition. Re-animating the shoulder is a high priority for restoring upper extremity function. Methods for reinnervating injured nerves include the transfer of a healthy nerve or fascicle distal to the site of injury, or grafting a healthy sensory nerve to restore motor function. Studies aiming to compare these two techniques for restoring shoulder abduction have yielded conflicting results. We conducted a systematic review and meta-analysis following the PRISMA guidelines. We reviewed the PubMed database for studies comparing nerve transfer and nerve grafting for shoulder abduction published by December 2018. Outcomes using the Medical Research Scale (MRC) for muscle strength were assessed using a random effects model meta-analysis. Five studies comprising a total of 212 patients (n = 158, nerve transfer; n = 54, nerve grafts) were used for the analysis. The rate of functional recovery of shoulder function was slightly better for nerve transfer (n = 114/158, 72%) than for nerve graft patients (n = 36/54, 67%). However, this was not statistically significant (OR 1.34, 95% CI 0.27–6.72, I2 = 62.9%). Nerve transfer and grafting are similarly effective in terms of shoulder abduction. Future prospective studies are needed to validate our results and identify the optimal shoulder re-animation strategy in patients with brachial plexus injuries.  相似文献   
2.
We report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5-mm pink-blue macule over the right zygomatic arch in an 85-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART-1, with high Ki-67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan-cytokeratin and Ber-EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease-free at 9 months after the initial diagnosis. The second tumor presented as a 6-mm pink-brown crusted papule on the right forehead in an 89-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART-1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM-SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic-epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.  相似文献   
3.
Disseminated histoplasmosis most commonly occurs in immunosuppressed individuals and involves the skin in approximately 6% of patients. Cutaneous histoplasmosis with an intraepithelial‐predominant distribution has not been described. A 47‐year‐old man was admitted to our institution with fever and vancomycin‐resistant enterococcal bacteremia. He had been diagnosed with T‐cell prolymphocytic leukemia 4 years earlier and had undergone matched‐unrelated‐donor stem cell transplant 2 years earlier; on admission, he had relapsed disease. His medical history was significant for disseminated histoplasmosis 6 months before admission, controlled with multiple antifungal regimens. During this final hospitalization, the patient developed multiple 2–5 mm erythematous papules, a hemorrhagic crust across the chest, shoulders, forearms, dorsal aspect of the fingers, abdomen and thighs. Skin biopsy revealed clusters of oval yeast forms mostly confined to the cytoplasm of keratinocytes and within the stratum corneum; scattered organisms were present in the underlying superficial dermis without any significant associated inflammatory infiltrate. Special stains and immunohistochemical studies confirmed these to be Histoplasma organisms. We highlight this previously unrecognized pattern of cutaneous histoplasmosis to ensure its prompt recognition and appropriate antifungal therapy.  相似文献   
4.
Purpose:To find the agreement and repeatability of Icare ic100 tonometer.Methods:We included 150 subjects above the age of 18 years for this cross-sectional, multicenter study with intraocular pressure (IOP) ≥7 mmHg. After the initial ophthalmic examination, two masked examiners took five IOP measurements using three different instruments; Icare ic100, Icare TA01i, and Goldmann applanation tonometer (GAT) in only one eye of the participants. Comparison of agreement of IOP using different instruments was quantified with intraclass correlation coefficient (ICC) using the two-way random effects models of absolute agreement and Cronbach''s alpha. The test-retest variability of the instruments was assessed by deriving repeatability coefficient (RC) and coefficient of variation (CV).Results:Agreement between the tonometers across the different IOP groups had no statistically significant difference in their mean IOP. Icare ic100 was found to have good reliability across all IOP groups (ICC value >0.78) when compared with Icare TA01i. In comparison with GAT, Icare ic100 showed good reliability across all IOP groups (ICC >0.87) except >16 to <23 mmHg group where it showed moderate reliability (ICC = 0.52). Icare ic100 showed good repeatability with RC and CV of 2.67 and 4.89, respectively.Conclusion:Icare ic100 rebound tonometer can measure IOP with relatively small measurement error and can provide a reliable and repeatable reading in comparison with GAT across a wide pressure range without hampering corneal health.  相似文献   
5.
Solution‐processable poly(dibenzalacetone) and poly(dibenzalcyclohexanone) are prepared by the condensation of 1,4‐dialkoxy‐bisbenzaldehyde and acetone/cyclohexanone using classic Claisen–Schmidt condensation. The prepared polymers are readily soluble in common organic solvents due to the presence of alkoxy chains present on the aromatic ring. The availability of α,β‐unsaturated ketone on the backbone is readily functionalized with hydrazine hydrate to obtain poly(pyrazoline acetate), a nonconjugated polymer on the backbone, which shows enhanced emission characteristics on comparison with the pristine polymer and small molecule analogues. The highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) of levels of poly(pyrazolines) has a band gap of 1.54 eV as calculated from cyclic voltammetry and UV–vis studies. Uniform thin film is obtained by spin casting as 1% solution on chlorobenzene and annealing under vacuum. Atomic force microscopy analysis shows fine morphology of the thin film. I–V characterization of the film shows low turn‐on voltage of 5.3 V. HOMO–LUMO is calculated by density functional theory and the result suggests that these molecules have great potential toward polymer organic light‐emitting diode applications.  相似文献   
6.
The tmRNA (transfer messenger RNA), encoded by ssrA gene, is involved in rescuing of stalled ribosomes by a process called trans-translation. Additionally, regions of the ssrA gene (coding for tmRNA) were reported to serve as integration sites for various bacteriophages. Though variations in ssrA genes were reported, their functional relevance is less studied. In this study, we investigated the horizontal gene transfer (HGT) of ssrA among the members of Enterobacteriaceae. This was done by predicting recombination signals in ssrA gene (belonging to Enterobacteriaceae) using RDP5 (Recombination Detection Program 5). Our results revealed 7 recombination signals in ssrA gene belonging to different species. We further showed that the recombination signals were more in the domains present in the 3′ end than 5′ end of tmRNA. Of note, the mRNA region was reported in many recombination signals. Further, members belonging to genera Yersinia, Erwinia, Dickeya and Enterobacter were highly represented in the recombination signals. Sequence analysis revealed the presence of integration sites for different class of bacteriophages in ssrA gene. The locations of phage recognition sites are comparable with recombination signals. Taken together, our results revealed a diverse nature of HGT and recombination which possibly due to transduction mediated by phages.  相似文献   
7.
Biopolymers are playing a vital role in biomedical applications. Among them, protein‐based biopolymers are utilized for the fabrication of tissue‐engineering constructs, therapeutic molecule delivery carriers, emulsifiers, and food packaging materials. Wide ranges of proteins are extracted from animal or plant sources and are being utilized for the fabrication of scaffolds for regenerative tissue‐engineering application. Here, an overview about the protein structure, extraction procedure, solubility, and various formulation‐based proteins found in the literature are discussed. Biopolymers display several advantages such as biocompatibility and degradability by enzymes. Methods to overcome the disadvantages of these proteins such as immunogenicity, antigenicity, and solubility are reported. Various crosslinking reagents specific to protein chemistry are discussed as well.  相似文献   
8.
Massive inguinoscrotal hernias extending below the midpoint of the inner thigh, in the standing position constitute giant inguinoscrotal hernias. We report a patient who presented with giant right inguinal hernia with bilateral hydrocele for 25 years. He had no cardiorespiratory illnesses. He was taken up for surgery under general anesthesia after preoperative respiratory exercises. Sliding hernia with entire greater omentum, small bowel, and appendix as contents was identified. Meshplasty after omentectomy with bilateral subtotal excision of sac, right orchidectomy, and scrotoplasty were done. Giant inguinoscrotal hernias pose significant problems while replacing bowel contents because of the increase in intraabdominal and intrathoracic pressures. Recurrence is another complication seen after successful surgical management. Various techniques such as preoperative pneumoperitoneum, debulking abdominal contents with extensive bowel resections, or omentectomy and phrenectomy have been tried. Postoperative elective ventilation is also needed in many cases. We describe simple reduction with omentectomy as a viable technique in this patient. He did not need elective ventilation due to preoperative respiratory exercises and preparation and review of the literature.Key words: Debulking, Giant inguinoscrotal hernia, Massive inguinoscrotal hernia, Phrenectomy, VentilationGiant inguinoscrotal hernias are defined as those extending below the midpoint of the inner thigh, in the standing position.1 These hernias are rare and usually the result of neglect or fear of surgical procedures and are prevalent in the rural population.2 These massive hernias pose significant problems resulting from cardiorespiratory compromise following sudden increase in intra-abdominal pressure during replacement of herniated viscera.3 In order to circumvent these complications, techniques such as debulking, phrenectomy, and progressive pneumoperitoneum have been described.3 Here, we present a patient with giant inguinoscrotal hernia where simple reduction with omentectomy was successful, and we review the literature.  相似文献   
9.
Multiple primary malignant neoplasm is the occurrence of a second primary malignancy in the same patient within 6 months of the detection of first primary (synchronous), or 6 months or more after primary detection (metachronous). Multiple primary malignant neoplasms are not very frequently encountered in clinical practice. The relative risk for a second primary malignancy increases by 1.111-fold every month from the detection of the first primary malignancy in any individual. We present 2 patients treated for carcinoma of the breast who developed a metachronous primary malignancy in the stomach to highlight the rare occurrence of multiple primary malignant neoplasms. These tumors were histologically dissimilar, with distinct immunohistochemical parameters. The importance lies in carefully identifying the second primary malignancies, not dismissing them as metastases, and treating them accordingly.Key words: Breast neoplasms, Stomach neoplasms, Neoplasms, Second primaryBreast cancer is the most common malignancy among women worldwide. With proper screening, earlier detection, and improved treatment, survival has greatly increased, with the result that there is now a large population of women with a present or past history of breast cancer. This has led to an increased detection of second primary malignancies among these women. The relative risk for a second primary malignancy increases by 1.111-fold every month from the detection of the first primary malignancy in any individual.1 Several authors have reported on a lesion in the stomach being labeled as a second primary malignancy and subsequently found to be metastasis. When the primary breast tumor is positive for estrogen and progesterone receptors (ER/PRs) and the stomach tumor is ER/PR negative, the diagnosis is established easily.2 However, studies have shown that some primary gastric cancers can have ER/PR positivity. Further, if the primary breast lesion is ER/PR negative, the same cannot be used as a marker. Here, we present 2 breast cancer patients who developed second primary malignancies in the stomach and the final diagnosis was established based on histopathology and immunohistochemistry.  相似文献   
10.
Thymomas are exceedingly rare tumours of the anterior mediastinum in children. An early awareness helps timely surgical intervention. Thymomas can occasionally be extremely aggressive. The loss of contour on chest X-Ray, to be confirmed as a large anterior mediastinal mass at computerised tomography, serves identification of a typical bilobed thymic tumour.  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