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   2094篇
  免费   129篇
  国内免费   5篇
耳鼻咽喉   11篇
儿科学   77篇
妇产科学   15篇
基础医学   291篇
口腔科学   67篇
临床医学   79篇
内科学   437篇
皮肤病学   30篇
神经病学   173篇
特种医学   62篇
外国民族医学   1篇
外科学   345篇
综合类   1篇
预防医学   16篇
眼科学   100篇
药学   236篇
中国医学   1篇
肿瘤学   286篇
  2023年   15篇
  2022年   27篇
  2021年   71篇
  2020年   27篇
  2019年   40篇
  2018年   60篇
  2017年   50篇
  2016年   63篇
  2015年   37篇
  2014年   55篇
  2013年   75篇
  2012年   136篇
  2011年   132篇
  2010年   87篇
  2009年   86篇
  2008年   138篇
  2007年   130篇
  2006年   99篇
  2005年   145篇
  2004年   144篇
  2003年   123篇
  2002年   119篇
  2001年   19篇
  2000年   31篇
  1999年   28篇
  1998年   24篇
  1997年   12篇
  1996年   12篇
  1995年   8篇
  1994年   4篇
  1993年   11篇
  1992年   21篇
  1991年   20篇
  1990年   20篇
  1989年   31篇
  1988年   17篇
  1987年   10篇
  1986年   17篇
  1985年   20篇
  1984年   12篇
  1983年   13篇
  1982年   5篇
  1981年   3篇
  1980年   6篇
  1979年   6篇
  1978年   4篇
  1977年   3篇
  1972年   2篇
  1971年   2篇
  1957年   1篇
排序方式: 共有2228条查询结果,搜索用时 15 毫秒
1.
2.
Risk is a concept inherent in every medical procedure. It can be defined as the probability of an adverse event in a defined population over a specified period of time. In the frame of food allergy management, it might be related to a diagnostic procedure, a treatment, or the consumption of foods. The risk of an adverse event can also be augmented by individual factors. This rostrum article discusses various aspects faced by children with food allergies in the light of risk, and their practical implications. Identifying personal risks for severe reaction, such as unstable asthma, and correcting them whenever possible also contribute to a reduction of the risk inherent to food allergy. Among the facets discussed, oral food challenges (OFC) are the most common diagnostic procedures implying an inherent risk. The risk of OFCs can be minimized by correct indication and timing of the test, a safe setting, as well as by ensuring that the patient is otherwise well without potential stressor potentially increasing the risk of a more severe reaction. Oral immunotherapy (OIT) has been studied as a potential treatment for increasing the threshold dose for reaction, and thus reducing the risk of accidental reaction. Nevertheless, the procedure is not devoid of risk as the patients may and do often react during the course of the procedure. Ingestion of trace amounts in processed foods, mainly in community settings such as restaurants, schools, or day care, represents a potential risk of reactions, although for a minority of patients. Precautionary allergen labeling (PAL) is a widespread strategy to reduce the potential risk of reactions due to traces. However, PAL is currently inefficient due to inconsistent labeling, also not indicating a clear maximum amount possibly present in the manufactured food. Finally, cost-effectiveness needs to be considered in risk management, as many risk reduction procedures are clearly not cost-effective.  相似文献   
3.
4.
The case of a 75-year-old man with three synchronous carcinomas of the lung (large cell carcinoma, adenocarcinoma, and small cell carcinoma) is reported. This is the eighth well-documented case report in the literature; however, our case is the first to be reported with the newly described histological combination.  相似文献   
5.
A stable cell line, KHM-3S, was established from a patient with small cell lung cancer (SCLC), who had a high serum level of soluble interleukin 2 receptors (sIL2-R) and was seropositive for human T cell leukemia virus (HTLV)-l. KHM-3S cells were positive for IL2-R (Tac) and NKH-1, but negative for other lymphocytic markers such as OKT 11, OKT 4, OKT 8, T cell receptor (WT 31), B 1, and B 4. Moreover, the KHM-3S cells were negative for leukocyte common antigen and strongly positive for neuron-specific enolase (NSE). Secretion of sIL2-R and NSE by the KHM-3S line was detected by an enzyme-linked immunosorbent assay. Rearrangement of the T cell receptor gene and monoclonal HTLV-1 integration were found by Southern blot analysis of KHM-3S DNA. However, Northern blot analysis showed no T cell receptor mRNA. KHM-3S may be useful for studies on the role of HTLV-1 in carcinogenesis and IL2-R expression in SCLC.  相似文献   
6.
Thirty persons with Class II Division 1 subdivision malocclusions, ranging in age from 12 years 8 months to 42 years, underwent computed tomography of the temporomandibular joints. The images obtained from sagittal slices were used to assess the depth of the mandibular fossa, the angulation of the posterior wall of the articular tubercle, the condyle-fossa relationship, and the concentric position of the condyles associated with this malocclusion. Paired Student t tests were applied, and Pearson product moment correlations (r) were determined after measurements on both Class I and Class II sides were obtained. No statistically significant asymmetries were found in the depth of the mandibular fossa, the angulation of the posterior wall of the articular tubercle, or the condyle-fossa relationship. However, a statistically significant (P <.05) anterior positioning of the condyles was observed.  相似文献   
7.
It has been known that clarithromycin (TE-031, A-56268), a new macrolide antibiotic (ML), achieves higher concentrations in blood, is better excreted into urine and is better distributed into various tissues than conventional MLs. We investigated the pharmacokinetics of TE-031 in children upon oral administration of the drug in the following method. TE-031 granular preparation with a potency of 100 mg/g was given to 6 boys (5 years 4 months-14 years 0 month) with dose levels of 5 mg/kg and 10 mg/kg for each 3 boys. A tablet preparation with each tablet containing 50 mg of TE-031 was administered to 4 boys and 2 girls (8 years 5 months-11 years 6 months) with dose level of 2 tablets (i.e., 100 mg) and 3 tablets (i.e., 150 mg) for each 3 children. All administrations were done at 30 minutes before meal. Then, to conduct a cross-over test, the granule preparation was given orally to the 3 children mentioned above who was given 2 tablets and the 1 of 3 cases that were given 3 tablets at the same dose levels (100 mg and 150 mg) respectively. A bioassay was used to determine concentrations in blood of active antibiotic compounds and an high performance liquid chromatography (HPLC) was used to determine unchanged TE-031 and its main metabolite, M-5. Urinary concentrations of active antibiotic compounds were also determined by the bioassay and the HPLC was used to determine concentrations and proportions of unchanged TE-031 and its metabolites, M-1, M-4, M-5, M-6 and M-7 to figure out the urinary recovery rate in the first 6 hours. The results of these experiments are summarized as follows. 1. As was mentioned above, TE-031 was administered orally to 2 groups of children at dose levels of 5 mg/kg and 10 mg/kg, respectively. Mean serum levels of total active antibiotic compounds reached their maximum in 1 and 2 hours for the 5 mg/kg and the 10 mg/kg dosage groups, respectively, at 1.28 and 3.62 micrograms/ml, respectively. Mean half lives of serum concentrations in the 2 groups were quite similar, with values of at 2.1 and 2.0 hours, respectively. Mean serum concentrations of unchanged TE-031 determined by the HPLC method reached their peaks in 1 hour after administration in either of the 5 and 10 mg/kg dosage groups at peak levels of 0.65 micrograms/ml and 2.67 micrograms/ml, respectively. Thus, dose-response relationships were observed with TE-031 and M-5.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
8.
To evaluate pharmacokinetics of amikacin (AMK), one of the aminoglycoside antibiotics, children with ages from 2 days to 11 years were treated with various doses by various administration routes, and both plasma and urinary levels of AMK were determined. The following is a summary of the results obtained: 1. Of 6 children, three were treated with 2.0 mg/kg of AMK by a 30-minute intravenous drip infusion, and the other 3 with 4.0 mg/kg by a 60-minute. Peaks of average plasma levels were observed at the ends of the infusions in both cases, and their levels were 9.23 and 13.67 micrograms/ml, respectively, showing a dose-dependency. Both half-lives and areas under plasma concentration-time curves (AUCs) were similar to those of adults. However, the volume of distribution (Vd) showed a lower value than that of adults. Peaks of average urine levels were 149.3 micrograms/ml with 2.0 mg/kg in 0-2 hours after the start of the infusion and 223.3 micrograms/ml with 4.0 mg/kg in 2-4 hours. Average urinary recovery rates within 6 hours after the start of the infusion were 95.4% with 2.0 mg/kg and 85.7% with 4.0 mg/kg. These recoveries were equal to or higher than that of adults. 2. When 3.0, 4.0 and 6.0 mg/kg of AMK were administered to 3 groups of mature or premature babies by intramuscular injection, average peak levels of AMK in plasma were 6.26, 8.61 and 12.60 micrograms/ml, respectively, at 30 minutes after the injection, showing dose-dependency. In these groups, the younger the day age after birth was, the longer the half-life became. The AUCs were larger as the half-life became longer. The Vd was larger than that in the intravenous drip infusion group, but, any particular was not observed. Average peak levels of AMK in urine were 78.83 micrograms/ml at 4-6 hours with a dose level of 3.0 mg/kg, 99.17 micrograms/ml at 2-4 hours with 4.0 mg/kg and 139.20 micrograms/ml at 0-2 hours with 6.0 mg/kg. Average urinary recovery rates within 6 hours were 36.57% with 3.0 mg/kg, 34.67% with 4.0 mg/kg and 43.77% with 6.0 mg/kg. These recovery rates were markedly lower than those observed in adults and children. One of the causes of this low recovery is that mature and premature babies have immature renal functions. 3. When 3.0 mg/kg of AMK was administered to three premature babies by a 30-minute intravenous drip infusion, the average peak plasma levels was 7.61 micrograms/ml at the end of the drip infusion.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
9.
10.
Fanconi-Bickel syndrome (FBS), or glycogen storage disease type XI, is a rare autosomal recessive disorder characterized by hepatorenal glycogen accumulation, Fanconi nephropathy, and impaired utilization of glucose and galactose. Recently, this disease was elucidated to link mutations in the glucose transporter 2 (GLUT2) gene. Only three mutations in three FBS families have been reported. Therefore, it is important to elucidate mutations in the GLUT2 gene in FBS by answering the question of whether the syndrome is a single gene disease. In this report, we describe two patients in two unrelated families clinically diagnosed with FBS. No mutation in the entire protein coding region of the GLUT2 gene was detected in patient 1, which suggested that no mutation existed in the GLUT 2 gene, or that some mutations had affected the expression of the GLUT 2 gene. In patient 2, a novel homozygous nonsense mutation (W420X, Trp at codon 420 to stop codon) was detected. These results support the correlation between GLTU2 gene mutation and FBS syndrome. However, many patients must be analyzed to determine whether other genes are involved in FBS. Received: July 16, 1999 / Accepted: September 3, 1999  相似文献   
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