全文获取类型
收费全文 | 34407篇 |
免费 | 2686篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 344篇 |
儿科学 | 1096篇 |
妇产科学 | 768篇 |
基础医学 | 4465篇 |
口腔科学 | 692篇 |
临床医学 | 3663篇 |
内科学 | 7421篇 |
皮肤病学 | 431篇 |
神经病学 | 2958篇 |
特种医学 | 1231篇 |
外国民族医学 | 2篇 |
外科学 | 4573篇 |
综合类 | 638篇 |
一般理论 | 14篇 |
预防医学 | 3267篇 |
眼科学 | 1080篇 |
药学 | 2129篇 |
中国医学 | 52篇 |
肿瘤学 | 2348篇 |
出版年
2023年 | 231篇 |
2022年 | 385篇 |
2021年 | 877篇 |
2020年 | 479篇 |
2019年 | 765篇 |
2018年 | 884篇 |
2017年 | 641篇 |
2016年 | 646篇 |
2015年 | 771篇 |
2014年 | 1061篇 |
2013年 | 1452篇 |
2012年 | 2202篇 |
2011年 | 2162篇 |
2010年 | 1261篇 |
2009年 | 1105篇 |
2008年 | 1863篇 |
2007年 | 1943篇 |
2006年 | 1775篇 |
2005年 | 1730篇 |
2004年 | 1679篇 |
2003年 | 1486篇 |
2002年 | 1484篇 |
2001年 | 697篇 |
2000年 | 681篇 |
1999年 | 636篇 |
1998年 | 320篇 |
1997年 | 301篇 |
1996年 | 257篇 |
1995年 | 279篇 |
1994年 | 250篇 |
1993年 | 236篇 |
1992年 | 466篇 |
1991年 | 462篇 |
1990年 | 452篇 |
1989年 | 420篇 |
1988年 | 375篇 |
1987年 | 356篇 |
1986年 | 380篇 |
1985年 | 351篇 |
1984年 | 278篇 |
1983年 | 245篇 |
1982年 | 191篇 |
1981年 | 164篇 |
1980年 | 165篇 |
1979年 | 210篇 |
1978年 | 160篇 |
1977年 | 165篇 |
1976年 | 138篇 |
1974年 | 163篇 |
1973年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
11.
12.
13.
Renaud Snanoudj Nassim Kamar Elisabeth Cassuto Sophie Caillard Marie Metzger Pierre Merville Antoine Thierry Isabelle Jollet Philippe Grimbert Dany Anglicheau Marc Hazzan Gabriel Choukroun Bruno Hurault De Ligny Bénedicte Janbon Vincent Vuiblet Anne Devys Yann Le Meur Michel Delahousse Jean-Luc Taupin 《Kidney international》2019,95(6):1471-1485
14.
Sebastian Bonner Thomas Matte Mitchell Rubin Joanne K Fagan Jennifer Ahern David Evans 《The Journal of asthma》2006,43(1):31-35
Although studies have documented underuse of controller medications and overuse of short-acting inhaled ss(2)-agonist among children with persistent asthma in disadvantaged communities, the persistence of oral ss(2)-agonist use in pediatric practice has not been studied since inhaled short-acting ss(2)-agonists became widespread. We describe medications used to treat asthma among children 3 to 5 years of age at 10 Head Start and other subsidized preschool centers in East and Central Harlem, New York City. We interviewed 149 parents/guardians of children who were identified as having probable asthma based on physician's diagnosis, persistent symptoms, hospitalization, and medication use. We classified 86 of the 149 children (58%) as having current persistent asthma. Only 15 of them (17%) were reported to have used controller medications at least 5 days/week in the last 4 weeks-only 2 of whom used inhaled corticosteroids. By contrast, 53 children (62%) used oral ss(2)-agonist in the last 4 weeks, often (72%) in conjunction with nebulized or inhaled short-acting ss(2)-agonist. Use of oral ss(2)-agonist was associated with more severe symptoms. This study documents the continued widespread use of oral ss(2)-agonist for treatment of children in a low-income community with high prevalence of asthma. 相似文献
15.
16.
17.
A Sharma H L Goh N Asokananthan A Bakker G A Stewart H W Mitchell 《The European respiratory journal》2006,27(1):20-28
Mucosal trypsin, a protease-activated receptor (PAR) stimulant, may have an endogenous bronchoprotective role on airway smooth muscle. To test this possibility the effects of lumenal trypsin on airway tone in segments of pig bronchus were tested. Bronchial segments from pigs were mounted in an organ chamber containing Kreb's solution. Contractions were assessed from isovolumetric lumen pressure induced by acetylcholine (ACh) or carbachol added to the adventitia. Trypsin, added to the airway lumen (300 microg x mL(-1)), had no immediate effect on smooth muscle tone but suppressed ACh-induced contractions after 60 min, for at least 3 h. Synthetic activating peptides (AP) for PAR1, PAR2 or PAR3 were without effect, but PAR4 AP caused rapid, weak suppression of contractions. Lumenal thrombin was without effect and did not prevent the effects of trypsin. Effects of trypsin were reduced by N(omega)-nitro-L-arginine methyl ester but not indomethacin. Trypsin, thrombin and PAR4 AP released prostaglandin E2. Adventitially, trypsin, thrombin and PAR4 AP (but not PAR2 AP) relaxed carbachol-toned airways after <3 min. The findings of this study show that trypsin causes delayed and persistent bronchoprotection by interacting with airway cells accessible from the lumen. The signalling mechanism may involve nitric oxide synthase but not prostanoids or protease-activated receptors. 相似文献
18.
19.
Chronic hepatitis C in patients with persistently normal alanine transaminase levels. 总被引:2,自引:0,他引:2
Mitchell L Shiffman Moisés Diago Albert Tran Paul Pockros Robert Reindollar Daniele Prati Maribel Rodríguez-Torres Pilar Lardelli Steven Blotner Stefan Zeuzem 《Clinical gastroenterology and hepatology》2006,4(5):645-652
BACKGROUND & AIMS: Many patients with chronic hepatitis C virus (HCV) have persistently normal serum alanine transaminase (ALT) levels. We compared characteristics of chronic hepatitis C patients with patients with normal and elevated ALT levels using data from 3 randomized phase III trials of peginterferon alfa-2a (40 kDa). METHODS: The characteristics of 480 patients with normal ALT values (on >or=3 occasions without any increases in ALT level over a 6- to 18-month period) and 1993 patients with elevated ALT levels were compared. Sixty-eight of the 480 patients with normal ALT levels were randomized to no treatment and monitored for 72 weeks. RESULTS: More patients with normal ALT levels than patients with elevated ALT levels were women (59% vs 32%; P<.01). The serum HCV RNA titer was significantly lower in patients with normal ALT levels (P<.01 vs in patients with elevated ALT levels). Patients with normal ALT levels had significantly lower inflammation and fibrosis scores on liver biopsy examination than patients with elevated ALT levels, but almost two-thirds had portal fibrosis and 10% had bridging fibrosis. No correlation between baseline ALT activity, HCV RNA level, and liver histology was observed in patients with normal ALT levels. During the 72-week follow-up period, ALT activity elevated above the upper limit of normal in 53% of the untreated patients with normal levels of ALT. None became HCV RNA undetectable. CONCLUSIONS: Chronic hepatitis C patients with normal ALT levels should be evaluated in a similar manner as patients with elevated ALT levels because they are at risk for developing significant liver disease. The decision to treat with peginterferon alfa and ribavirin should be based on multiple factors, rather than on ALT levels alone. 相似文献
20.
A case illustrating the potentially fatal complication of endogenous Gram Negative Aerobic Bacillus (GNAB) septicaemia secondary to nosocomial pneumonia is presented along with current theories as to its aetiology. The technique of selective decontamination of the digestive tract is designed and advocated to prevent such occurrences; oral and maxillofacial surgeons should be aware of this approach. It may be, however, that by using much simpler manoeuvres such as changes in policy regarding gastric stress ulcer prophylaxis, the already small risk of such an occurrence will be further reduced. Awareness of this condition will allow a higher index of suspicion when presented with catastrophic septic complications on the ITU and aid in more rational planning of antimicrobial therapy. 相似文献