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   1853篇
  免费   97篇
  国内免费   7篇
耳鼻咽喉   11篇
儿科学   88篇
妇产科学   21篇
基础医学   181篇
口腔科学   42篇
临床医学   118篇
内科学   373篇
皮肤病学   60篇
神经病学   102篇
特种医学   39篇
外科学   317篇
综合类   60篇
一般理论   11篇
预防医学   100篇
眼科学   124篇
药学   190篇
中国医学   8篇
肿瘤学   112篇
  2023年   21篇
  2022年   72篇
  2021年   157篇
  2020年   77篇
  2019年   104篇
  2018年   98篇
  2017年   70篇
  2016年   78篇
  2015年   85篇
  2014年   125篇
  2013年   126篇
  2012年   167篇
  2011年   137篇
  2010年   76篇
  2009年   61篇
  2008年   79篇
  2007年   60篇
  2006年   40篇
  2005年   44篇
  2004年   16篇
  2003年   24篇
  2002年   29篇
  2001年   23篇
  2000年   22篇
  1999年   14篇
  1998年   5篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   4篇
  1993年   4篇
  1992年   15篇
  1991年   15篇
  1990年   19篇
  1989年   10篇
  1988年   12篇
  1987年   3篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1982年   2篇
  1980年   4篇
  1979年   3篇
  1978年   3篇
  1977年   6篇
  1976年   6篇
  1975年   4篇
  1972年   3篇
  1966年   5篇
  1965年   3篇
排序方式: 共有1957条查询结果,搜索用时 0 毫秒
101.
Gliosarcoma, a variant of isocitrate dehydrogenase‐wildtype glioblastoma, is largely a lobar surfacing neoplasm often with dural attachment. In this biphasic neoplasm, the sarcomatous component usually takes the form of fibrosarcoma or malignant fibrous histiocytoma. Heterologous sarcomatous differentiation is a rare phenomenon. Here, we present a case of gliosarcoma with liposarcomatous and myosarcomatous differentiation in a 68‐year‐old man which was purely intraventricular. This is the first report of such a morphologic pattern in this location. Varied histological components with their immunohistochemical profile are discussed. Of note was the presence of a p53 negative giant cell glioblastoma component, as was the expression in the rest of the tumor.  相似文献   
102.
Introduction  The study was carried out to quantify the changes induced by the pandemic in plastic surgery practice and training and to study the impact of the webinars on plastic surgery education from a residents’ perspective. Methods  In this multicentric study, the number and type of surgeries, cause of injuries, and their regional variation during the coronavirus disease 2019 (COVID-19) period (February–September 2020) were compared with pre–COVID-19 time. An online survey on the impact of webinars was conducted for plastic surgery trainees across the country. Results  There was a significant reduction in total number of surgeries ( p = 0.003). The procedures for hand ( p = 0.156), faciomaxillary injuries ( p = 0.25), and replantations ( p = 0.46) were comparable; there was a significant reduction in combined orthopedic-plastic-surgical procedures ( p = 0.009) during the pandemic. There was a significant reduction in road accidents ( p = 0.007) and suicidal injuries ( p = 0.002) and increase in assault ( p = 0.03) and domestic accidents ( p = 0.01) during the COVID-19 period. A usefulness score of >8 was given for the webinars by 68.7% residents. There was no significant difference in perception of utility when correlated with the academic program at their institutes ( p = 0.109); 92% opined webinars should continue in post-COVID times. Conclusion  There was a drastic reduction in number of elective and emergency procedures during the COVID-19 time, negatively affecting resident training program. Majority of residents felt that webinars could prove a useful adjunct to training in formal training program in post-COVID-19 scenario.  相似文献   
103.
The present study was undertaken to isolate a novel antidiabetic molecule from Swietenia macrophylla seeds. The hydroalcohol extract of Swietenia macrophylla seeds was subjected for bioassay guided isolation employing glucose utilization assay by the isolated rat hemi‐diaphragm method in vitro. One tetranortriterpenoid, swietenine, isolated from the chloroform fraction exhibited significant (p < 0.01) activity and the effect was comparable to that of human insulin (p < 0.01). Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
104.
The present study describes the in vivo effects of anti-leprosy drugs on rat peritoneal macrophages and T-cell homeostasis. It was observed that BCG-elicited rat peritoneal macrophages produced more H2O2 and expressed more Ia antigen on their cell surfaces compared with resident peritoneal macrophages. Furthermore, elicited macrophages isolated from rats administered multidrug therapy (MDT), consisting of dapsone, clofazimine and rifampicin in high dose (10 x MDT) released more O2-. On the contrary, there was a significant decrease in the Ia antigen expression on these macrophages. Anti-leprosy drug treatment in high dose (10 x MDT) decreased the total number of blood T-helper (W3/25+) cells and increased the total number of blood T-suppressor (OX-8+) cells which resulted in a significant decrease in a W3/25: OX-8 ratio. Electron microscopy of elicited macrophages isolated from 10 x MDT treated rats showed development of many filipodia compared with control macrophages. These data show that 10 x MDT treatment in rats for 1 month alters the homeostasis of blood T-cell subpopulations which perhaps decreases the Ia expression on macrophages. However, the increase in O2- production and the appearance of filipodia on the macrophages is due to a direct effect of drugs on the macrophages. MDT treatment for 1 month in a therapeutic dose has no effect on the above-mentioned parameters.  相似文献   
105.
106.
107.
The most common cause of proximal radioulnar synostosis in adults is traumatic, usually after forearm fractures. Disabling complications are mainly loss of rotatory movements of the forearm. Various surgical procedures have been described in the literature to end up in forearm synostosis as a complication. We here presented a rare case of proximal forearm synostosis following a common but improper surgical technique for an olecranon fracture complicated by implant infection. The synostosis was treated by resection and fascia lata interposition graft.  相似文献   
108.
India is endemic for foot-and-mouth disease (FMD) and in recent years a unique group within serotype A, carrying a codon deletion at an antigenically critical site in capsid protein VP3 has emerged (VP359-deletion group). This tempted us to analyze the noncoding region, which is an under represented area, though critically associated with virus biology and pathogenesis. Analysis of the large fragment of 5′ untranslated region (LF-5′ UTR) of type A FMD virus revealed discrepancy in the overall tree topology between LF-5′ UTR and 1D region possibly due to independent evolution of coding and noncoding regions. The VP359-deletion group maintained its phylogenetic distinctness even at the LF-5′ UTR. Eighteen lineage specific signatures detected here support independent evolutionary paths for the lineages. Extensive deletions of 45 and 89 nucleotides corresponding to the pseudoknot region were noticed. Conservation pattern in the ‘A253AACA’ motif in the cre/bus stem-loop indicates the importance of first three ‘A’ residues in VPg uridylylation. Of the three polypyrimidine tract binding protein (PTB) binding sites mapped on the internal ribosome entry site (IRES), the pyrimidine tract (Py tract) in the loop of domain 2 was found to be maximally conserved and it might be the major PTB binding site. Strikingly, a deletion group lineage specific transversion was noticed in the Py tract at the 3′ end of IRES without significantly affecting its in vitro infectious titer. Hence, we presume that for efficient cap-independent viral translation, either a minimum number of pyrimidine residues rather than a complete Py tract or a Py tract tolerating transversions only at specific locations and a core motif ‘CUUU’ within the Py tract is essential.  相似文献   
109.
Mucormycosis of the anterior abdominal wall is an uncommon disease and it is very rare to find this disease in immunocompetent, non-diabetic patients which usually affects patients with trauma, with contaminated wounds, patients with underlying malignancies or patients with immunocompromised state, e.g., diabetics. We herein report a case of primary cutaneous mucormycosis in an immunocompetent and non-diabetic patient. Our patient was a 48-year-old female, executive by profession. She was diagnosed to have cutaneous mucormycosis of the anterior abdominal wall, and was managed with multiple debridements of the wound and intravenous amphotericin B therapy. She was administered a total of 1500 mg of liposomal amphotericin B and when fully healed, split skin grafting was done. We would like to emphasize the importance of high index of suspicion and early start of therapy in a condition with high rate of mortality.  相似文献   
110.
ObjectiveTo estimate the overall quality-adjusted life-years (QALYs) gained by averting 1 coronavirus disease 2019 (COVID-19) infection over the duration of the pandemic.MethodsA cohort-based probabilistic simulation model, informed by the latest epidemiological estimates on COVID-19 in the United States provided by the Centers for Disease Control and Prevention and literature review. Heterogeneity of parameter values across age group was accounted for. The main outcome studied was QALYs for the infected patient, patient’s family members, and the contagion effect of the infected patient over the duration of the pandemic.ResultsAverting a COVID-19 infection in a representative US resident will generate an additional 0.061 (0.016-0.129) QALYs (for the patient: 0.055, 95% confidence interval [CI] 0.014-0.115; for the patient’s family members: 0.006, 95% CI 0.002-0.015). Accounting for the contagion effect of this infection, and assuming that an effective vaccine will be available in 3 months, the total QALYs gains from averting 1 single infection is 1.51 (95% CI 0.28-4.37) accrued to patients and their family members affected by the index infection and its sequelae. These results were robust to most parameter values and were most influenced by effective reproduction number, probability of death outside the hospital, the time-varying hazard rates of hospitalization, and death in critical care.ConclusionOur findings suggest that the health benefits of averting 1 COVID-19 infection in the United States are substantial. Efforts to curb infections must weigh the costs against these benefits.  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