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   1009篇
  免费   67篇
  国内免费   3篇
耳鼻咽喉   8篇
儿科学   53篇
妇产科学   61篇
基础医学   132篇
口腔科学   37篇
临床医学   87篇
内科学   190篇
皮肤病学   16篇
神经病学   33篇
特种医学   22篇
外科学   81篇
综合类   9篇
预防医学   58篇
眼科学   78篇
药学   94篇
中国医学   4篇
肿瘤学   116篇
  2024年   1篇
  2023年   12篇
  2022年   26篇
  2021年   57篇
  2020年   22篇
  2019年   42篇
  2018年   42篇
  2017年   27篇
  2016年   49篇
  2015年   40篇
  2014年   50篇
  2013年   52篇
  2012年   90篇
  2011年   89篇
  2010年   48篇
  2009年   34篇
  2008年   74篇
  2007年   68篇
  2006年   61篇
  2005年   46篇
  2004年   46篇
  2003年   45篇
  2002年   37篇
  2001年   5篇
  2000年   2篇
  1999年   4篇
  1998年   5篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1992年   1篇
排序方式: 共有1079条查询结果,搜索用时 78 毫秒
91.
Results of thyroid biopsy determine whether thyroid nodule resection is appropriate and the extent of thyroid surgery. At our institution we use 20/22-gauge core biopsy (CBx) in conjunction with fine-needle aspiration (FNA) to decrease the number of passes and improve adequacy. Occasionally, both ultrasound (US)-guided FNA and CBx yield unsatisfactory specimens. To justify clinical recommendations for these unsatisfactory thyroid biopsies, we compare rates of malignancy at surgical resection for unsatisfactory biopsy results against definitive biopsy results. We retrospectively reviewed a database of 1979 patients who had a total of 2677 FNA and 663 CBx performed by experienced interventional radiologists under US guidance from 2003 to 2006 at a tertiary-care academic center. In 451 patients who had surgery following biopsy, Fisher’s exact test was used to compare surgical malignancy rates between unsatisfactory and malignant biopsy cohorts as well as between unsatisfactory and benign biopsy cohorts. We defined statistical significance at P = 0.05. We reported an overall unsatisfactory thyroid biopsy rate of 3.7% (100/2677). A statistically significant higher rate of surgically proven malignancies was found in malignant biopsy patients compared to unsatisfactory biopsy patients (P = 0.0001). The incidence of surgically proven malignancy in unsatisfactory biopsy patients was not significantly different from that in benign biopsy patients (P = 0.8625). In conclusion, an extremely low incidence of malignancy was associated with both benign and unsatisfactory thyroid biopsy results. The difference in incidence between these two groups was not statistically significant. Therefore, patients with unsatisfactory biopsy specimens can be reassured and counseled accordingly.  相似文献   
92.
Juvenile nasopharyngeal angiofibrama (JNA) is a benign vascular tumour which is locally aggressive and occasionally extends intracranially. It occurs mainly in adolescent males. We report an interesting case of a targe JNA with intracranial extention encroaching on the cavernous sinus which we treated surgically by the conventional lateral rhinotomy and transpalatal approach.  相似文献   
93.
Tension pneumocephalus is an unusual, potentially life-threatening complication of frontal fossa tumors. We present an uncommon case of a frontoethmoidal osteoma causing a tension pneumocephalus and neurological deterioration prompting a combined endonasal ethmoidectomy and bifrontal craniotomy with craniofacial approach for resection. A 68-year-old man presented with a 1-week history of worsening headache, slowness of speech, and increasing confusion. Standard computed tomography scan revealed a marked tension pneumocephalus with ventricular air and 1-cm midline shift to the right. Further studies showed a calcified left ethmoid mass and a left anterior cranial-base defect. A team composed of neurosurgery and otolaryngology performed a combined endonasal ethmoidectomy and bifrontal craniotomy with craniofacial approach to resect a large frontoethmoid bony tumor. No abscess or mucocele was identified. The skull base defect was repaired with the aid of a transnasal endoscopy, a titanium mesh, and a pedunculated pericranial flap. Postoperatively, the pneumocephalus and the patient's symptoms completely resolved. Pathology was consistent with a benign osteoma. This is an uncommon case of a frontoethmoidal osteoma associated with tension pneumocephalus. Recognition of this entity and timely diagnosis and treatment, consisting of an endonasal ethmoidectomy and a bifrontal craniotomy with craniofacial approach, may prevent potential life-threatening complications.  相似文献   
94.
We report a case of primary renal carcinoid arising in a horseshoe kidney. To the best of our knowledge this is the first case to be reported in the cytology literature, which has been diagnosed by fine needle aspiration (FNA). A 32-year-old male, presented to the Emory University Hospital, with a renal mass arising in a horseshoe kidney; along with a thyroid mass. FNA of the renal mass resulted in an initial diagnosis of renal cell carcinoma, unclassified. A thyroid aspiration was attempted later, and revealed a neuroendocrine morphology. This was compared with the renal aspiration and both of them were found to have similar morphology. With the help of immunostains, a diagnosis of renal carcinoid tumor metastatic to the thyroid was made. Thus, we demonstrate that renal carcinoid, being a rare entity, can pose a diagnostic challenge.  相似文献   
95.
HIV-1 Vif regulates viral infectivity by inhibiting the encapsidation of APOBEC3G (APO3G) through proteasomal degradation of the protein. Here we compared various Vif proteins for their ability to induce APO3G degradation and rescue viral infectivity. We found that Vif expressed from proviral vectors caused relatively inefficient degradation of APO3G in HeLa cells yet was very effective in inhibiting APO3G's antiviral activity. On the other hand, Vif expressed autonomously from a codon-optimized vector caused very efficient APO3G degradation and also effectively inhibited APO3G's antiviral effects. In contrast, a Vif chimera containing an N-terminal fluorescent tag efficiently induced APO3G degradation but was unable to restore viral infectivity. The lack of a direct correlation between APO3G degradation and rescue of viral infectivity suggests that these two properties of Vif are functionally separable. Our data imply that intracellular degradation of APO3G may not be the sole activity of Vif required for the production of infectious virions from APO3G-expressing cells.  相似文献   
96.
Providing safe water to >1 billion people in need is a major challenge. To address this need, the Safe Water System (SWS) - household water treatment with dilute bleach, safe water storage, and behavior change - has been implemented in >20 countries. To assess the potential sustainability of the SWS, we analyzed costs in Zambia of "Clorin" brand product sold in bottles sufficient for a month of water treatment at a price of $0.09. We analyzed production, marketing, distribution, and overhead costs of Clorin before and after sales reached nationwide scale, and analyzed Clorin sales revenue. The average cost per bottle of Clorin production, marketing and distribution at start-up in 1999 was $1.88 but decreased by 82% to $0.33 in 2003, when >1.7 million bottles were sold. The financial loss per bottle decreased from $1.72 in 1999 to $0.24 in 2003. Net program costs in 2003 were $428,984, or only $0.04 per person-month of protection. A sensitivity analysis showed that if the bottle price increased to $0.18, the project would be self-sustaining at maximum capacity. This analysis demonstrated that efficiencies in the SWS supply chain can be achieved through social marketing. Even with a subsidy, overall program costs per beneficiary are low.  相似文献   
97.
OBJECTIVE: We report the clinical concerns of US veterans of Operations Iraqi Freedom and Enduring Freedom evaluated at the New Jersey War-Related Illness and Injury Study Center (NJ WRIISC) between June 2004 and January 2006. METHODS: We conducted a retrospective chart review of veterans' health and exposure concerns. RESULTS: Veterans (n=56) reported an average of 4 (standard deviation [SD] = 2.1; range, 0-9) physical health concerns, and 2.7 (SD=2.3; range, 0-10) exposure concerns. The majority of veterans (55%) had a mental health concern, most commonly, posttraumatic stress disorder. The most common exposure concerns were depleted uranium, multiple vaccinations, and poor air quality. Greater proportions of Reserve veterans reported genitourinary concerns and exposure to smoke from burning trash than active duty veterans. CONCLUSIONS: Veterans of military operations in Southwest Asia have deployment-related health and exposure concerns that will need to be addressed by their ambulatory care physicians.  相似文献   
98.
BackgroundPatients with multiple myeloma (MM) aged ≤ 65 to 70 years, with a good Eastern Cooperative Oncology Group performance status and no major comorbid conditions, are considered potential candidates for autologous stem cell transplant (ASCT) and will be treated with novel agent-based induction therapy for 4 to 6 cycles before ASCT.Patients and MethodsWe analyzed the data from 326 patients with MM who had received novel agent-based induction before ASCT at our center to evaluate the effect of induction therapy on ASCT response, stem cell mobilization, engraftment characteristics, and survival. The median age was 52 years (range, 29-72 years), 216 patients were men (66.3%), 32.7% had stage III using the Revised Multiple Myeloma International Staging System, and 15.8% had high-risk cytogenetics. Of the 326 patients, 75 (23.0%) had undergone ASCT in second remission after salvage therapy for relapse. Also, 194 patients (59.5%) had received doublet induction therapy and 132 (40.5%) had received triplet induction therapy.ResultsTriplet-based induction therapy was superior to doublet-based therapy for response (95.4% vs. 84.02%; P < .003), stem cell mobilization (CD34+ ≥ 2 × 106/kg; 88.6% vs. 76.8%; P < .005), and lower 100-day transplant-related mortality (P < .001). The ≥100 day post-ASCT overall response (97.4% vs. 91.7%; P = .124) and complete response (72.5% vs. 68.0%; P = .38) rates were similar. At a median follow-up of 62.5 months, the overall survival (97.5 months vs. 100.0 months; P = .606) and progression-free survival (54.5 months vs. 57 months; P = .515) were similar between the triplet and doublet induction groups.ConclusionAn initial response (chemosensitivity) to induction therapy will prepare patients better for subsequent consolidation therapy and ASCT, leading to favorable outcomes.  相似文献   
99.

Introduction

Sporadic reports on individual ossified ligaments of the middle cranial fossa (MCF) fail to do justice to their grave clinical consequences. The present study attempts a comprehensive search for all ossified ligaments and associated accessory foramina in relation to MCF, in order to standardize baseline prevalence pertinent for the Indian subcontinent.

Methods

Fifty well-preserved and intact, adult (age >20 yrs), dry, macerated skulls were obtained from the Anatomy departments of medical colleges in Delhi, including the All India Institute of Medical Sciences. All the skulls were subjected to a meticulous, bilateral examination and digital photography of internal & external aspects of the skull base, to look for presence of partially or completely ossified ligaments and resulting accessory foramina.

Results

The incidence values recorded from the present sample (n = 50 × 2) for completely (C) and incompletely (IC) ossified MCF ligaments are as follows: Caroticoclinoid: C = 6 (6%), IC = 2 (2%); Interclinoid: C = 3 (3%), IC = 2 (2%); Pterygospinous: C = 2 (2%), IC = 3 (3%); Pterygoalar: C = 1 (1%), IC = 2 (2%); Petrosphenoid/petroclinoid: C = 2 (2%), IC = 0 (0%). All completely ossified ligaments were found to be associated with accessory foramina.

Discussion

Presence of ossified MCF ligaments cannot be overlooked in patients with symptoms arising from compression of neurovascular structures and those undergoing skull-base neurosurgery, necessitating pre-surgical screening for presence of calcified ligaments in close proximity to vital structures ? a scenario that may influence surgical outcome.  相似文献   
100.
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