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   698篇
  免费   36篇
  国内免费   8篇
耳鼻咽喉   8篇
儿科学   65篇
妇产科学   24篇
基础医学   63篇
口腔科学   32篇
临床医学   69篇
内科学   160篇
皮肤病学   15篇
神经病学   49篇
特种医学   19篇
外科学   133篇
综合类   18篇
预防医学   20篇
眼科学   13篇
药学   24篇
肿瘤学   30篇
  2023年   2篇
  2022年   7篇
  2021年   12篇
  2020年   9篇
  2019年   16篇
  2018年   26篇
  2017年   14篇
  2016年   11篇
  2015年   22篇
  2014年   27篇
  2013年   50篇
  2012年   47篇
  2011年   49篇
  2010年   36篇
  2009年   36篇
  2008年   57篇
  2007年   69篇
  2006年   78篇
  2005年   60篇
  2004年   42篇
  2003年   26篇
  2002年   24篇
  2001年   1篇
  1999年   2篇
  1998年   2篇
  1997年   4篇
  1995年   2篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
排序方式: 共有742条查询结果,搜索用时 46 毫秒
131.
Heteropagous conjoined twins are rare and umbilical heteropagous conjoined twins are extremely rare. We present a case with umbilical heteropagous conjoined twins and discuss the diagnosis and management. The parasitic component of heteropagous can be separated and treated successfully in the majority of cases.  相似文献   
132.
OBJECTIVE: An endometrioid adenocarcinoma (EAC) with true trophoblastic differentiation is a rare event with a highly aggressive clinical course. CASE: We report an endometrioid adenocarcinoma of the endometrium in which there was a morphologically conventional-appearing EAC component admixed with multinucleated giant cells and large pleomorphic tumor cells that resembled a choriocarcinoma without an elevated serum level of human chorionic gonadotropin (hCG) in a 42-year-old unmarried woman with a history of abnormal uterine bleeding. A total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection were performed. Histopathologic study of the specimen showed endometrioid adenocarcinoma extended to the deep myometrium with a focus of hemorrhagic and necrotic tumor composed of multinucleated giant cells, large pleomorphic tumor cells, suggesting choriocarcinomatous differentiation (CD). Immunohistochemical studies demonstrated intense reactivity of tumor cells for human chorionic gonadotropin (hCG) confirming the diagnosis. A complete clinical workup ruled out metastatic spread to the brain, lungs, skeleton, or abdomen. The patient was alive with no evidence of disease 6 months later. CONCLUSION: Although endometrioid adenocarcinoma with choriocarcinomatous differentiation is known to behave in a more aggressive course, this disease may have a good prognosis with a clinically indolent course when it is small, and without elevated serum hCG levels.  相似文献   
133.

Background

Isolated distal vaginal agenesis is a rare anomaly and mostly becomes symptomatic after menarche. We describe an unusual presentation of this anomaly in a prepubertal girl.

Case

An 11-year-old prepubertal girl presented with recurrent urinary tract infection, pyuria, and right-sided renal agenesis. The findings of perineal inspection, ultrasonography, and magnetic resonance imaging were consistent with a distal vaginal agenesis with pyometrocolpos. Discharging pyometrocolpos with dissection of the atretic portion and a pull-through vaginoplasty were performed. A cystoscopy showed no sign of a vesicovaginal or uterine fistula.

Summary and Conclusion

This rare presentation of distal vaginal agenesis reminds us that congenital malformations of the female genital tract should be considered in patients with congenital anomalies of the urinary system and/or recurrent urinary tract infection, even during the prepubertal period.  相似文献   
134.
The essential oil from the bark of Cinnamomum zeylanicum Blume was analyzed by GC–MS and bioassays were carried out. Nine constituents representing 99.24% of the oil were identified by GC–MS. The major compounds in the oil were (E)-cinnamaldehyde (68.95%), benzaldehyde (9.94%) and (E)-cinnamyl acetate (7.44%). The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against 21 bacteria and 4 Candida species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested. The cytotoxic and apoptotic effects of the essential oil on ras active (5RP7) and normal (F2408) fibroblasts were examined by MTT assay and acridine orange/ethidium bromide staining, respectively. The cytotoxicity of the oil was quite strong with IC50 values less than 20 μg/mL for both cell lines. 5RP7 cells were affected stronger than normal cells. Morphological observation of apoptotic cells indicated the induction of apoptosis at the high level of the oil, especially in 5RP7 cells. The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of cinnamon bark, indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections and neoplasms.  相似文献   
135.
Cytomegalovirus (CMV) is a ubiquitous latent human virus that often causes complications in renal transplantation recipients. Universal prophylaxis and preemptive therapy are alternative strategies to prevent CMV associated complications. This meta‐analysis aimed to assess available data comparing the effectiveness of prophylaxis and preemptive therapy for preventing adverse outcomes. We searched the PubMed, Ovid, Web of Science, Cochrane Library, and Open Grey databases using a combination of keywords. Random effects models along with the Paule‐Mandel estimator were used to synthesize pooled effect estimates. Eleven studies were eligible for the final analysis. Universal prophylaxis was better at preventing CMV disease than the preemptive approach (risk difference = ?0.0459; confidence intervals = ?0.0791, ?0.0127; P‐value = 0.0067; number needed to treat [NNT] = 22 [1/0.0459]; high, 79 [1/0.0127] patients; low, 13 [1/0.0791] patients). Subgroup analysis revealed a more consistent effect among studies published after 2010, with negligible between‐study heterogeneity. The NNT for universal prophylaxis to prevent one excess CMV disease concerning preemptive therapy was 16 (1/0.0630) patients (high, 25 [1/0.0394]; low, 12 [1/0.0867] patients) in the subgroup of studies performed after 2010. We detected no significant difference between the two strategies regarding acute rejection and graft loss, with negligible variability due to heterogeneity between studies. Although universal prophylaxis performed better than the preemptive strategy for the prevention of CMV disease, the high NNT value may discourage the use of CMV prophylaxis. Since there were no differences between the strategies concerning acute rejection and graft loss, this study supports the use of the preemptive approach as an alternative to universal prophylaxis.  相似文献   
136.
Germline biallelic mutations in one of the mismatch repair genes, mutS homolog 2, mutS homolog 6, mutL homolog 1, or postmeiotic segregation increased 2, result in one of the most aggressive cancer syndromes in humans termed as constitutional mismatch repair deficiency (CMMRD). Individuals with CMMRD are affected with multiple tumors arising from multiple organs during childhood, and these individuals rarely reach adulthood without specific interventions. The most common tumors observed are central nervous system, hematological, and gastrointestinal malignancies. The incidence of CMMRD is expected to be high in low‐resource settings due to a high rate of consanguinity in these regions, and it is thought to be underrecognized and consequently underdiagnosed. This position paper is therefore important to provide a summary of the current situation, and to highlight the necessity of increasing awareness, diagnostic criteria, and surveillance to improve survival for patients and family members.  相似文献   
137.
138.
Background: The aim of the study was to explore the differences in oxidative stress during anesthesia with desflurane/N2O or propofol/remifentanil in patients undergoing laparoscopic cholecystectomy and additionally to evaluate the differential effects of desflurane and propofol on ischemic preconditioning (IP).

Materials and methods: One hundred patients were randomly allocated to four groups. For anesthesia maintenance, the inhalation group (Group I) and the inhalation plus IP group (Group IIP) received desflurane at an end-tidal concentration of 4–6 vol% in oxygen/N2O, and the TIVA group (Group T) and TIVA plus IP group (Group TIP) received infusions of propofol and remifentanil. In Groups IIP and TIP, IP was carried out by 10?min of pneumoperitoneum followed by 10?min of deflation. Preoperative and postoperative plasma total antioxidant status (TAS), total oxidant status (TOS), paraoxonase, stimulated paraoxonase, arylesterase, ceruloplasmin, and myeloperoxidase levels were analyzed; oxidative stress index (OSI) was calculated.

Results: When oxidative stress parameters were compared between groups, myeloperoxidase values in Group I were statistically significantly lower compared to Group TIP (p?=?.004 with Bonferroni’s correction). There were no differences between preoperative and postoperative TAS, paraoxonase, stimulated paraoxonase, arylesterase, or ceruloplasmin levels (p?>?.05). In intragroup evaluations, postoperative paraoxonase and stimulated paraoxonase levels were found to be lower than preoperative values in Group TIP (p?=?.021 and .012, respectively).

Conclusion: In laparoscopic cholecystectomy lasting less than 60?min, there were no differences in the measured oxidative stress parameters between maintenance of anesthesia by desflurane/N2O and propofol/remifentanil/N2O. The addition of 10?min IP administration during both anesthesia techniques did not result in additional changes in the analyzed oxidative stress.  相似文献   
139.
Clinical and laboratory parameters usually allow an easy diagnosis of acute lymphoblastic leukemia in most cases. Difficulty arises, however, when presentation is atypical. A young child with membranous tonsillo-pharyngitis secondary to an isolated neutropenia is reported. The neutrophilic count later showed fluctuations reminiscent of cyclic neutropenia. Bone marrow examination revealed the true nature of underlying disorder.  相似文献   
140.
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