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   19554篇
  免费   1369篇
  国内免费   56篇
耳鼻咽喉   179篇
儿科学   537篇
妇产科学   434篇
基础医学   2524篇
口腔科学   593篇
临床医学   2063篇
内科学   4307篇
皮肤病学   484篇
神经病学   2282篇
特种医学   488篇
外科学   2183篇
综合类   78篇
一般理论   18篇
预防医学   1903篇
眼科学   234篇
药学   1074篇
  1篇
中国医学   32篇
肿瘤学   1565篇
  2024年   46篇
  2023年   297篇
  2022年   478篇
  2021年   923篇
  2020年   573篇
  2019年   831篇
  2018年   926篇
  2017年   630篇
  2016年   665篇
  2015年   696篇
  2014年   917篇
  2013年   1172篇
  2012年   1676篇
  2011年   1637篇
  2010年   850篇
  2009年   711篇
  2008年   1137篇
  2007年   1093篇
  2006年   1009篇
  2005年   987篇
  2004年   815篇
  2003年   717篇
  2002年   705篇
  2001年   126篇
  2000年   100篇
  1999年   117篇
  1998年   139篇
  1997年   97篇
  1996年   100篇
  1995年   85篇
  1994年   72篇
  1993年   59篇
  1992年   58篇
  1991年   55篇
  1990年   56篇
  1989年   51篇
  1988年   34篇
  1987年   39篇
  1986年   40篇
  1985年   29篇
  1984年   26篇
  1983年   29篇
  1982年   25篇
  1981年   12篇
  1980年   25篇
  1979年   16篇
  1976年   13篇
  1974年   9篇
  1971年   8篇
  1970年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
BackgroundShort gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis.MethodsFemale juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature.ResultsA statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ± 0.7 vessels, after: 4.7 ± 1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ± 3.0 vessels/mm, spring: 7.0 ± 9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ± 3.0 vessels/mm, spring: 8.0 ± 8.0 vessels/mm, p = 0.003).ConclusionIntestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine.Level of evidenceN/AType of studyTreatment study.  相似文献   
92.
93.
94.
PurposeMetastatic recurrence occurs in over 25% of upper tract urothelial carcinoma patients treated with radical nephroureterectomy. While metastatic recurrence suggests poor prognosis, the impact of the specific site of recurrence on prognosis is not well documented.Materials and methodsWe retrospectively analyzed 188 patients who underwent radical nephroureterectomy for high-grade, node-negative upper tract urothelial carcinoma at our institution from 2003 to 2018 without receiving neoadjuvant or adjuvant chemotherapy. Competing-risks survival analysis was performed to evaluate the cumulative incidence and predictors of metastatic recurrence. The Kaplan-Meier method and log-rank test were used to estimate and compare recurrence site-specific survival probabilities following metastatic recurrence. Cox regression analyses were performed to assess site-specific prognoses.ResultsOf the 188 patients, 47 (25%) developed metastatic recurrence over a median follow-up of 30 months (interquartile range: 10.5–58.5 months). The 1- and 2-year cumulative incidences of metastatic recurrence were 13.6% and 23.6%, respectively. On multivariable analysis, lymphovascular invasion was significantly predictive of metastatic recurrence (subhazard ratio: 2.6, P = 0.01). Of the 47 patients who developed recurrence, 38 (80.9%) died over a median follow-up of 10 months (interquartile range: 5–20 months). Metastatic recurrence was most common in the lungs (n= 13, 28%) and at multiple sites (n= 14, 30%). Median time to recurrence was shorter for recurrences at multiple sites (6.5 months) and those in the liver (13 months) and bone (18 months) compared to other sites. Patients who recurred in the liver (hazard ratio: 6.3, P = 0.007), bone (hazard ratio: 4.9, P = 0.02), and multiple sites (hazard ratio: 4.6, P = 0.01) had significantly worse prognosis compared to those who recurred in lymph nodes. Statistical significance persisted after adjusting for treatment with salvage therapy.ConclusionsA significant proportion of high-grade upper tract urothelial carcinoma patients recur systemically after radical nephroureterectomy. Lymphovascular invasion is a predictor of metastatic recurrence and may inform decisions regarding perioperative chemotherapy. Hepatic and osseous recurrences have relatively quicker onset and less favorable prognosis compared to other sites. These findings may benefit future efforts to develop recurrence site-specific treatment plans and highlight the necessity of subsequent endeavors to explore the genetic associations of recurrence in upper tract urothelial carcinoma.  相似文献   
95.
Objective: Intravesical Bacillus Calmette-Guèrin (BCG) is an effective treatment in non––muscle-invasive bladder cancer, however, extravesical BCG infection may occur in remote organs as a potentially serious complication. Researchers aimed to assess whether a different timing of BCG infection after intravesical administration of BCG could be identified and estimated for each single involved organ. Methods: We performed a systematic literature review over systemic and genitourinary BCG infection case reports, including 271 published case reports for a total of 307 patients. Demographic data, clinical features, and timing of BCG infection development were collected and analyzed for each patient. Results: BCG infection developed with a different timing from last instillation, depending on the involved organ. Among the genitourinary complications, penile lesions occurred as early as 1 (1;3) weeks, while orchiepididymitis occurred as late as 56 (6.25;156) weeks. At the same time, granulomatous hepatitis and lungs involvement such as miliary pulmonary BCG infection occurred earlier, with a median time of 1 (1;4) and 1 (1;6) weeks respectively, whereas vascular, osteoarticular, and muscular complications developed with a median timing from last instillation of 52 (20;104), 68 (14;156), and 93 (29;156) weeks, respectively. The analysis detected a cluster between lungs, liver, and bone marrow complications on one side and muscular and osteoarticular or vascular complications on the other side was also observed. Conclusions: BCG infection after intravesical BCG for bladder cancer may develop even several months or years after the last instillation, depending on the involved organs. When BCG infection interests one or more organ, 2 main associative patterns are common: one involving lungs, liver, and bone marrow, with earlier occurrence but lower rates of microbiological diagnosis achievement, and one involving muscular and osteoarticular or vascular districts, with later occurrence but higher rates of microbiological evidence.  相似文献   
96.
BackgroundOur aim in this study was to identify the fibular footprint of the Anterior Inferior Tibiofibular Ligament (AITFL) and its relation to Wagstaffe fracture fragment size.MethodsWe examined 25 cadaveric lower limbs which were carefully dissected to identify the lateral ankle ligaments. The AITFL anatomy was compared to 40 Wagstaffe fractures identified from our ankle fracture database.ResultsThe AITFL origin was from the anterior fibular tubercle with an average length of 21.61 mm (95% CI 20.22, 22.99). The average distance of the distal aspect of the AITFL footprint to the distal fibula margin was 11.60 mm (95% CI 10.49, 12.71). In the ankle fractures analyzed, the average length of the Wagstaffe fragment was 17.88 mm (95% CI 16.21, 19.54). The average distance from the distal tip of the fibula to the Wagstaffe fracture fragment was 21.40 mm (95% CI 19.78, 23.01).In total there were 22 syndesmosis injuries. There was no statistical difference in Wagstaffe fragment size between stable and unstable groups.ConclusionThe AITFL fibular origin was both larger and more distal than the Wagstaffe fracture fragments seen in our institution. Therefore, this suggests that a ligamentous failure will also have to occur to result in syndesmotic instability. The size of fracture fragment also did not confer to syndesmotic instability on testing.Level of Evidence - 3  相似文献   
97.
Multifocal cystic oncocytosis (MCO) is a rare, benign process accounting for approximately 0.1% of salivary gland lesions. Salivary oncocytosis is characterized by multiple unencapsulated solid nodules of oncocytic cells derived from transformed striated ducts. MCO is a variant of salivary oncocytosis which manifests as cystically dilated striated ducts. It is difficult to obtain a definitive preoperative diagnosis of MCO; therefore, these lesions are commonly treated with surgery. We report the unique case of a 66-year-old male who previously underwent a superficial left parotidectomy for a pleomorphic adenoma. Four years later, he presented with clinical and radiographic suspicion of a multifocal recurrent pleomorphic adenoma. The patient subsequently underwent a revision parotidectomy. However, final pathology confirmed a diagnosis of MCO. Although MCO is commonly treated with surgery due to lack of a definitive preoperative diagnosis, surgery is unnecessary outside of diagnostic, functional or cosmetic considerations. Thus, if a patient with parotid oncocytosis treated by superficial parotidectomy develops disease re-manifestation in the residual deep lobe, further surgery is not indicated. There is no risk of malignant progression in this process. We report on this unusual entity as it may mimic salivary malignancy or, as in this case, recurrence of benign disease.  相似文献   
98.

While often included in the spectrum of sexual minority identities, asexuality receives comparatively little attention. Awareness and understanding remains limited, and knowledge has been generated primarily from adult populations. This paper employs a sample of 711 self-identified asexual youth (aged 14–24, M?=?17.43 years) who identified as members of the LGBTQ+?community to consider the implications of a number of different areas for service provision. Two-thirds (66.8%) of participants identified as gender minorities within the spectrum of transgender and non-binary identities. Findings include aspects of participants’ LGBTQ+?developmental processes, including that only 14.3% had disclosed their LGBTQ+?status to everyone in their lives. However, just 2.4% had disclosed to no one. Their attraction and sexual activity were also explored, with 27.1% having never experienced any kind of romantic or sexual attraction and 20.6% having ever been sexually active. Findings regarding participants’ accessing of LGBTQ+?health information and engagement in a range of offline and online LGBTQ+?community activities are also provided. Participants acquired more health information online than offline—including sexual health information. Recommendations for service provision, particularly implications for sexual health and Internet-based services, are discussed.

  相似文献   
99.
ObjectiveWe sought to assess how women interpret the information they find online about the overall safety and risk of infertility associated with abortion and cesarean delivery (CD).MethodsWe conducted an exploratory, prospective study tracking the internet searches of 100 reproductive-aged individuals who identify as women. We directed participants to search for information about either (1) whether surgical abortion or CD is safe or (2) the risk of infertility following surgical abortion or CD. Our data collection had 3 phases: baseline survey, directed internet search, and a postsearch survey. We analyzed participants’ pre- and postsurvey responses using bivariate tests and analyzed within-subject changes. We evaluated the sites they visited based on expert ratings of site content based on trustworthiness and slant.ResultsWomen perceived abortion as safer and less likely to cause infertility after their web searches than before (70% perceived abortion in the United States as very/completely safe presearch vs 92% postsearch; p < 0.02). Women's perceptions about CD did not change. Participants sought information from web pages that experts largely deemed trustworthy and lacking in slant.ConclusionsWomen's perceptions about abortion safety and risk can be influenced by information they find online; perceptions about CD safety and risk may be less influenced by online information.ImplicationsDisseminating high quality, user-friendly abortion information on highly ranked and easily findable websites can help women find evidence-based information and influence knowledge about abortion.  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