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   20739篇
  免费   1066篇
  国内免费   150篇
耳鼻咽喉   220篇
儿科学   445篇
妇产科学   195篇
基础医学   2314篇
口腔科学   367篇
临床医学   1447篇
内科学   5826篇
皮肤病学   434篇
神经病学   1591篇
特种医学   781篇
外科学   3881篇
综合类   49篇
预防医学   493篇
眼科学   395篇
药学   1098篇
中国医学   49篇
肿瘤学   2370篇
  2024年   31篇
  2023年   193篇
  2022年   390篇
  2021年   686篇
  2020年   370篇
  2019年   465篇
  2018年   620篇
  2017年   411篇
  2016年   574篇
  2015年   537篇
  2014年   761篇
  2013年   864篇
  2012年   1387篇
  2011年   1618篇
  2010年   897篇
  2009年   802篇
  2008年   1312篇
  2007年   1358篇
  2006年   1319篇
  2005年   1385篇
  2004年   1420篇
  2003年   1275篇
  2002年   1169篇
  2001年   180篇
  2000年   164篇
  1999年   194篇
  1998年   241篇
  1997年   229篇
  1996年   157篇
  1995年   136篇
  1994年   144篇
  1993年   109篇
  1992年   86篇
  1991年   73篇
  1990年   55篇
  1989年   42篇
  1988年   37篇
  1987年   39篇
  1986年   30篇
  1985年   18篇
  1984年   30篇
  1983年   18篇
  1982年   22篇
  1981年   17篇
  1980年   16篇
  1979年   10篇
  1978年   10篇
  1977年   7篇
  1976年   9篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
262.
Engineered skin substitutes are widely used in skin wound management. However, no currently available products satisfy all the criteria of usability in emergency situations, easy handling, and minimal scar formation. To overcome these shortcomings, we designed a cell‐free bandage‐type artificial skin, named “VitriBand” (VB), using adhesive film dressing, silicone‐coated polyethylene terephthalate film, and collagen xerogel membrane defined as a dried collagen vitrigel membrane without free water. We analyzed its advantages over in‐line products by comparing VB with hydrocolloid dressing and collagen sponge. For evaluation, mice inflicted with full‐thickness skin defects were treated with VB, hydrocolloid dressing, and collagen sponge. A plastic film group treated only with adhesive film dressing and silicone‐coated polyethylene terephthalate film, and a no treatment group were also compared. VB promoted epithelization while inhibiting the emergence of myofibroblasts and inflammation in the regenerating tissue more effectively than the plastic film, hydrocolloid dressing, and collagen sponge products. We have succeeded in establishing a cell‐free bandage‐type artificial skin that could serve as a promising first‐line medical biomaterial for emergency treatment of skin injuries in various medical situations.  相似文献   
263.
264.
Background:   Osteoporosis is believed to result from the interaction among multiple environmental and genetic determinants that regulate bone-mineral density (BMD).
Methods:   To investigate a potentially predisposing genetic factor in the onset of osteoporosis, we looked for a possible association between BMD in adult Japanese women and known polymorphisms in the leukemia inhibitory factor receptor gene (LIFR).
Results:   An association analysis of chromosomes from 384 volunteer subjects revealed significant correlation between the −603T > C variant of LIFR and radial BMD ( r  = 0.11, P  = 0.032) in this test population. Comparisons of mean values of adjusted radial BMD among separate genotypic groups implied an allelic dosage effect, because homozygous carriers of T alleles of that SNP had the highest adjusted BMDs (0.403 ± 0.054 g/cm2); women homozygous for the C-allele had the lowest (0.373 ± 0.042 g/cm2), and heterozygous individuals had intermediate scores (0.394 ± 0.056 g/cm2).
Conclusion:   This polymorphism in LIFR may be an important determinant of predisposition to postmenopausal osteoporosis.  相似文献   
265.
We present a patient with complication of huge hepatic subcapsular hematoma after extracorporeal shock wave lithotripsy (ESWL) for pancreatic lithotripsy. The hematoma measured 78–110 mm. Angiography showed a subcapsular hematoma, rather than a hematoma in the liver. In the arterial phase, the distal end of the small vessel showed spotty opacification similar to microaneurysma, suggesting that it was an injury caused by separation of the liver and its capsule, caused by the shock waves. The portal vein and hepatic vein were normal. After 8 weeks of conservative therapy, the hematoma was gradually absorbed and the patient was discharged. Eight months after the accident, the hematoma had decreased to 40 mm in size. After 20 months, it was completely absorbed. The reported rate of renal subcapsular hematoma after ESWL for renal or ureter stones is 0.1%–0.7%. To date, however, only five cases of hepatic subcapsular hematoma after right renal stone disintegration have been reported. This is the first report of hepatic subcapsular hematoma after ESWL for pancreatic stones. Received: September 11, 1998 / Accepted: April 16, 1999  相似文献   
266.
Typical Turcot's syndrome is characterized by the association of a brain glioma together with multiple colonic polyposis, in which the number of polypoid lesions is small and the association of colonic cancer occurs at a younger age than in familial adenomatous polyposis. We describe a family in which both the father and his son presented with typical Turcot's syndrome without parental consanguinity. This is the first report of a family that is considered to follow an autosomal dominant inheritance. After reviewing 25 documented cases in which the average age of death was 20.3 years old, it was learned that the major cause of death was brain tumor (76 percent) and the minor cause was colon cancer (16 percent). Patients were very young and, therefore, unlikely to have produced a child before their death. These facts seem to support the theory that Turcot's syndrome is an autosomal dominant disorder.  相似文献   
267.
268.
Background Because genotype A of hepatitis B virus (HBV) is not indigenous, there have been only few data on infection with it in Japan.Methods We examined clinical and virological features of the 66 Japanese patients who admitted Toranomon Hospital in Tokyo, Japan, between 1976 and 2001, who were found to have HBV/A infection. HBV genotype A was classified into subtype A (European type) and A (South African type) by phylogenetic analysis of the preS1 and preS2 regions, and the S gene sequences.Results Of the 66 patients infected with HBV/A, 14 (21%) were asymptomatic carriers, 26 (39%) presented with acute hepatitis, 22 (33%) with chronic hepatitis, and 4 (6%) with liver cirrhosis. HBV/A infection persisted for more than 6 months in 5 of the 26 (19%) patients with acute hepatitis. The frequency of acute hepatitis in patients infected with HBV/A was higher after than before 1991 (2/22 [9%] vs 24/44 [55%]; P < 0.0001). The frequency of nucleotide 1858 of T was higher in asymptomatic carriers than in patients with acute hepatitis in whom infection was resolved (5/14 [36%] vs 0/21 [0%]; P = 0.008). Of the 57 patients for whom subtypes of genotype A were determined, subtype A was identified in 53 (93%) and subtype A in only 4 (7%). All patients infected with subtype A were persistently infected with HBV.Conclusions HBV/A infection has become more frequent during recent years, predominantly presenting as acute hepatitis, and subtype A is uncommon in the Tokyo metropolitan area.  相似文献   
269.
270.
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