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   11628篇
  免费   499篇
  国内免费   13篇
耳鼻咽喉   59篇
儿科学   375篇
妇产科学   574篇
基础医学   1128篇
口腔科学   86篇
临床医学   1338篇
内科学   2183篇
皮肤病学   139篇
神经病学   1183篇
特种医学   558篇
外科学   1600篇
综合类   43篇
一般理论   6篇
预防医学   1111篇
眼科学   92篇
药学   1088篇
中国医学   4篇
肿瘤学   573篇
  2023年   236篇
  2022年   303篇
  2021年   346篇
  2020年   330篇
  2019年   290篇
  2018年   284篇
  2017年   304篇
  2016年   305篇
  2015年   296篇
  2014年   668篇
  2013年   704篇
  2012年   474篇
  2011年   432篇
  2010年   425篇
  2009年   450篇
  2008年   479篇
  2007年   445篇
  2006年   451篇
  2005年   397篇
  2004年   346篇
  2003年   358篇
  2002年   353篇
  2001年   334篇
  2000年   338篇
  1999年   324篇
  1998年   135篇
  1997年   114篇
  1996年   127篇
  1995年   50篇
  1994年   54篇
  1993年   42篇
  1992年   227篇
  1991年   240篇
  1990年   228篇
  1989年   226篇
  1988年   215篇
  1987年   102篇
  1986年   22篇
  1985年   63篇
  1984年   69篇
  1983年   69篇
  1982年   64篇
  1981年   64篇
  1980年   60篇
  1979年   49篇
  1978年   37篇
  1977年   33篇
  1976年   37篇
  1974年   29篇
  1973年   27篇
排序方式: 共有10000条查询结果,搜索用时 264 毫秒
1.
2.
Background: Individuals with cerebral palsy (CP) are at increased risk for obesity and obesity-related complications. Studies of total body fat in those with CP are inconsistent and studies of abdominal fat are lacking in children with CP. The objective of this study was to determine if ambulatory children with spastic CP have greater central adiposity compared to typically developing children. Methodology: Eighteen ambulatory children with spastic CP (n = 5 girls; 8.6 ± 2.9 yr) and 18 age-, sex-, and race-matched typically developing children (controls; 8.9 ± 2.1 yr) participated in this cross-sectional study. Children with CP were classified as I or II using the Gross Motor Function Classification System. Dual-energy X-ray absorptiometry assessed body composition, including total body, trunk and abdominal fat mass, fat-free mass, fat mass index (FMI), and fat-free mass index (FFMI). Results: There were no group differences in fat mass, fat-free mass, FMI, and FFMI in the total body, fat mass, fat-free mass, and FFMI in the trunk, or fat mass, visceral fat mass, and subcutaneous fat mass in the abdomen (p > 0.05). Compared to controls, children with CP had higher trunk FMI, abdominal FMI, and visceral FMI (p < 0.05). Although marginally insignificant (p = 0.088), children with CP had higher subcutaneous FMI. Conclusions: Ambulatory children with spastic CP have elevated central adiposity, especially in the visceral region, despite no differences in measures of total body fat. How this relates to cardiometabolic disease progression in those with CP requires further investigation.  相似文献   
3.
Behçet disease is a complex, multisystem disease characterized by recurrent oral and genital ulcerations. It rarely occurs in infants or children. Neonatal Behçet disease has been reported in infants whose ulcers resolve at or before 9 weeks of age. Few cases of neonatal Behçet disease persisting into childhood have previously been reported. We report the case of a 1‐month‐old infant who presented with severe recurrent genital ulcerations and at 6 months developed recurrent oral ulcerations. Her orogenital ulcerations continue to recur. Human leukocyte antigen testing revealed HLA‐B51 and B44 positivity. This is a case of pediatric Behçet disease in the neonatal period. Behçet disease should be considered in the differential diagnosis of recurrent genital and oral ulcerations in infants and children.  相似文献   
4.
5.
We evaluated the performance of the Luminex ARIES® C. difficile Assay on 984 stool specimens prospectively collected from patients being tested for CDI at 4 clinical laboratories in the United States. Results were compared to direct and enriched toxigenic culture. Positive percent agreement (PPA) of the ARIES® C. difficile Assay was 98.1% versus direct toxigenic culture, and sensitivity versus direct plus enriched toxigenic culture was 90.5%. Negative percent agreement (NPA) of the ARIES® C. difficile Assay against direct culture was 92.6%, and specificity versus direct plus enriched toxigenic culture was 95.8%. The ARIES® C. difficile Assay was also compared to the results of routine (molecular, antigen, and/or toxin) methods for C. difficile testing used at each institution. The PPA of the ARIES® C. difficile Assay ranged from 82.9% to 100%. NPA values against these commercial assays ranged from 94.5% to 100%.  相似文献   
6.
BackgroundHeavy metal contamination has become a serious issue in this century especially detected in fish organs. Due to the presence of radioactive compounds in agricultural and sewage effluent, which destroys aquatic ecosystems, threatening human livelihoods. Health hazards associated with low and high consumption consumers assessed in five commercial fish species collected from Hurghada City, Egypt, during winter and summer, 2020. Atomic absorption spectrophotometer technique used for determination heavy meals in different organs and expressed as μg/g wet weight.ResultsHeavy metal concentrations in muscle ranged between:(0.054–0.109), (0.260–1.043), (0.264–0.897), (5.895–11.898), (0.381–0.970), (13.582–29.133) and (0.332–0.589) µg/g for Cd, Pb, Mn, Zn, Cu, Fe and Ni respectively, which were lower than those of gills and liver. These concentrations were within WHO, FAO/WHO, and EU standards. Consumption of edible species was lower than the (TDIs) established by the (JECFA) and Egyptian Standards. Even though THQ and TTHQ values were < 1 while, in children with highly consumer were> 1.ConclusionThis study concluded that intake of Red Sea fish is safe for human health. It is critical for consumers to be aware of the consequences of excessive fish consumption, particularly children with highly consumer, which represent possible health risks.  相似文献   
7.
Management of rectal cancer has evolved extensively over the last 30 years. Treatment of locally advanced rectal cancer currently incorporates surgery, chemotherapy, and radiation. Radiation was initially utilized as a salvage method as historic surgical practices were associated with high morbidity rates. In present day, multiple studies have demonstrated that the use of radiation as an adjunct to surgery decreases local recurrence rates. The now routine practice of total mesorectal excision during rectal cancer surgery has further improved outcomes. Numerous studies have evaluated the chemotherapeutic regimens as adjuncts to radiation therapy. Currently, fluorouracil-based regimens are commonly incorporated into neoadjuvant therapy for locally advanced rectal cancer, whereas oxaliplatin has not been incorporated due to more recent studies demonstrating increased toxicity and no clear oncologic benefit. Presently, trials are underway that aim to tailor therapies to specific patterns of disease, in hopes of allowing clinicians to selectively omit components of therapy to limit toxicity and morbidity while maintaining or improving oncologic outcomes. Thus, rectal cancer treatment continues to evolve, and decision-making surround treatment remains highly individualized and nuanced.  相似文献   
8.
Immune thrombotic thrombocytopenic purpura (iTTP) is a chronically relapsing, humorally-mediated autoimmune disorder characterized by unpredictable episodes of microangiopathic hemolytic anemia and thrombocytopenia, commonly associated with neurologic dysfunction, kidney injury, and fever. Episodes are caused by immune destruction or inhibition of the von Willebrand Factor (vWF) cleaving protease ADAMTS13. Currently, the standard of care is therapeutic plasma exchange (TPE), and most add immunosuppression with corticosteroids - a standard that is unchanged for nearly 30 years. There are multiple strategies for adding corticosteroids to TPE and the limited data available suggests that corticosteroids reduce the duration of ADAMTS13 deficiency in iTTP. Rituximab is also frequently used in the treatment of iTTP and evidence suggests that while it may not reduce the number TPE procedures required to induce remission, it likely increases relapse-free survival. Novel approaches to immunosuppression that have been reported include low-dose rituximab (also currently in clinical trials) and proteasome inhibition. A more targeted approach includes the anti-vWF nanobody, caplacizumab, recently approved for iTTP in Europe and United States, which in two large randomized controlled trials significantly shortened the time to normalization of platelet count, appreciably lowered the 30-day recurrence rate, and decreased the rate of the composite endpoint of death, recurrence, and major thromboembolic events. Recombinant ADAMTS13 has been tested in congenital TTP and could be tested in iTTP as well, along with novel approaches of modifying the enzyme to avoid the immune response or leveraging other vWF cleaving proteases such as plasmin to bypass ADAMTS13. Also, therapies that target preformed antibodies that are currently being tested in other humorally-mediated disorders could cross over to iTTP. Finally, progress has long been hampered in iTTP due to difficulty with accrual and disagreement about trial design. A good surrogate endpoint for relapse-free survival is also needed. Despite these challenges, a new era of precision medicine is likely soon emerging for treatment of iTTP, and with it comes the opportunity to further improve outcomes in this rare and deadly disease.  相似文献   
9.
Deoxynivalenol (DON) has broad toxicity in animals and humans. In this study the impact of DON treatment on apoptotic pathways in PC12 cells was determined. The effects of DON were evaluated on (i) typical indicators of apoptosis, including cellular morphology, cell activity, lactate dehydrogenase (LDH) release, and apoptosis ratio in PC12 cells, and on (ii) the expression of key genes and proteins related to apoptosis, including Bcl-2, Bax, Bid, cytochrome C (Cyt C), apoptosis inducing factor (AIF), cleaved-Caspase9, and cleaved-Caspase3. DON treatment inhibited proliferation of PC12 cells, induced significant morphological changes and apoptosis, promoted the release of Cyt C and AIF from the mitochondria, and increased the activities of cleaved-Caspase9 and cleaved-Caspase3. Bcl-2 expression decreased with increasing DON concentrations, in contrast to Bax and Bid, which were increased with increasing DON concentration. These data demonstrate that DON induces apoptosis in PC12 cells through the mitochondrial apoptosis pathway.  相似文献   
10.
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