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   2059篇
  免费   138篇
  国内免费   6篇
耳鼻咽喉   4篇
儿科学   64篇
妇产科学   31篇
基础医学   246篇
口腔科学   24篇
临床医学   191篇
内科学   498篇
皮肤病学   25篇
神经病学   362篇
特种医学   73篇
外科学   152篇
综合类   20篇
预防医学   140篇
眼科学   90篇
药学   170篇
中国医学   4篇
肿瘤学   109篇
  2022年   22篇
  2021年   43篇
  2020年   26篇
  2019年   43篇
  2018年   58篇
  2017年   42篇
  2016年   46篇
  2015年   37篇
  2014年   71篇
  2013年   96篇
  2012年   100篇
  2011年   127篇
  2010年   73篇
  2009年   66篇
  2008年   139篇
  2007年   135篇
  2006年   119篇
  2005年   143篇
  2004年   121篇
  2003年   126篇
  2002年   103篇
  2001年   15篇
  2000年   14篇
  1999年   15篇
  1998年   14篇
  1997年   23篇
  1996年   16篇
  1995年   13篇
  1994年   13篇
  1993年   14篇
  1992年   13篇
  1991年   11篇
  1990年   9篇
  1989年   9篇
  1988年   7篇
  1986年   12篇
  1985年   12篇
  1984年   16篇
  1983年   14篇
  1982年   22篇
  1981年   20篇
  1980年   14篇
  1979年   12篇
  1978年   11篇
  1977年   16篇
  1976年   19篇
  1972年   9篇
  1966年   5篇
  1963年   7篇
  1961年   6篇
排序方式: 共有2203条查询结果,搜索用时 46 毫秒
1.
OBJECTIVE: To determine if there is a diurnal pattern in the clinical symptoms of HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. STUDY DESIGN: A retrospective study was performed in 134 pregnancies complicated by HELLP syndrome. The medical records were reviewed to describe each HELLP episode. Time of day was divided into three periods, day, evening, and night. The following parameters were categorized according to the time of day: onset of symptoms, consultation by the doctor, initial blood sampling, diagnosis and decrease of symptoms. Biochemical parameters at clinical presentation and consecutive changes within 24 h were recorded. RESULTS: In 65 pregnancies 77 HELLP episodes were well documented. Times of onset of symptoms and consultation by the doctor were significantly higher during the evening and night (p < 0.001), whereas times of diagnosis and decrease of symptoms occurred significantly more during the day (p < 0.001). In only 49.3% of the cases were diagnostic laboratory criteria met at clinical presentation. This was mainly due to platelet values in excess of 100 x 10(9)/l. Several hours later (median 8 h, range 2-23) the decrease in platelets occurred. CONCLUSIONS: A diurnal pattern exists in the clinical symptoms of HELLP syndrome that is characterized by an exacerbation during the night and recovery during the day. There is a considerable delay between the onset of symptoms and the fulfillment of diagnostic laboratory criteria.  相似文献   
2.
3.
This paper reviews evidence from clinical, epidemiologic, and family studies regarding the association between social phobia and other syndromes. Social phobia is strongly associated with other anxiety disorders, substance abuse, and affective disorders in both clinical and community samples. An average of 80% of social phobics identified in community samples meet diagnostic criteria for another lifetime condition. Social phobia is most strongly associated with other subtypes of anxiety disorders, with an average of 50% of social phobics in the community reporting a concomitant anxiety disorder including another phobic disorder, generalized anciety, or panic disorder. Approximately 20% of subjects in the community meet lifetime criteria for a major depressive disorder. The onset of social phobia generally precedes that of all other disorders, with the exception of simple phobia. Both clinical severity and treated prevalence are consistently greater among social phobics with comorbid disorders The results of family and twin studies reveal that shared etiologic factors explain a substantial proportion of the comorbidity between social phobia and depression, whereas the association between social phobia and alcoholism derives from a nonfamilial causal relationship between the two conditions. Clinical and phenomenologic implications of these findings are discussed.  相似文献   
4.
MK-679 (R(?)-3-((3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)(3-(dimethylamino)-3-oxopropyl)thio)methyl)thio(propanoic acid) is a potent and specific LTD4-receptor antagonist. The disposition of MK-679 was investigated in a three-way crossover study in 12 healthy males receiving single intravenous doses of 75, 250, and 500 mg of MK-679. A greater than proportional increase in the area under the plasma concentration—time curve of MK-679 was observed with increase in dose. The plasma concentration data for each subject fitted well to the differential equations for a two-compartment model with linear tissue distribution and Michaelis-Menten elimination from the central compartment, indicating that the elimination of MK-679 in humans is saturable. In a previous study, the disposition of MK-679 in humans was also dose-dependent when given together with its S(+)-isomer, L-668,018. Thus, the disposition of MK-679 in humans is dose-dependent regardless of the presence of its stereoisomer. Also, the bioavailability of MK-679 was determined in six healthy males receiving simultaneously an oral dose of 250 mg of MK-679 and intravenous infusion of 1 mg 14C-MK-679. Results of this study indicate that the oral bioavailability of MK-679 is nearly quantitative.  相似文献   
5.
6.
7.
8.

Background  

Job satisfaction is important for nursing home staff and nursing home management, as it is associated with absenteeism, turnover, and quality of care. However, we know little about factors associated with job satisfaction and dissatisfaction for nursing home workers.  相似文献   
9.
Malignancy is a major risk factor for venous thromboembolic events, but not all patients with malignancy develop such events. This study attempts to identify risk factors in patients with malignancy who develop venous thromboembolic events. In the current study, 566 consecutive patients without venous thromboembolic events and 416 patients with, admitted to University of Michigan with malignancy between 1992 and 2000, were identified using International Classification of Diseases-9 Clinical Modification codes. Data on potential risk factors was obtained from the University of Michigan Cancer Registry and the medical record. Univariate and multivariate analysis was used to identify factors associated with venous thromboembolic events and mortality. The mean patient age was 45.6 years with a mean survival of 7.8 years from cancer diagnosis. Venous thromboembolic events were associated with solid tumors (odds ratio 5.0; 95% confidence interval 1.7-14.9; P = 0.004), infection (4.9; 1.2-19.8; P = 0.03), and increasing age (1.05; 1.03-1.08; P < 0.001). While leukopenia (4.2; 1.2-14.6; P = 0.02) was associated with an increased incidence of venous thromboembolic events, neutropenia was not. Sex, type of therapy, and cancer stage were not independently associated with venous thromboembolic events. Survival was decreased in patients with venous thromboembolic events (5.9 versus 9.2 years, P < 0.0001). Solid tumors (3.9; 1.8-8.4; P = 0.001), infection (3.3; 1.1-9.9; P = 0.03), advanced stage (1.6; 1.2-2.1; P = 0.001), and increasing age (1.02; 1.0-1.04; P = 0.01) were associated with decreased survival. Patients with malignancy who have solid tumors, advanced age, infection, and leukopenia have a significantly increased risk of venous thromboembolic events.  相似文献   
10.
The aim of this study is to improve the dissolution properties of a poorly-soluble active substance, Eflucimibe by associating it with gamma-cyclodextrin. To achieve this objective, a new three-step process based on supercritical fluid technology has been proposed. First, Eflucimibe and cyclodextrin are co-crystallized using an anti-solvent process, dimethylsulfoxide being the solvent and supercritical carbon dioxide being the anti-solvent. Second, the co-crystallized powder is held in a static mode under supercritical conditions for several hours. This is the maturing step. Third, in a final stripping step, supercritical CO(2) is flowed through the matured powder to extract the residual solvent. The coupling of the first two steps brings about a significant synergistic effect to improve the dissolution rate of the drug. The nature of the entity obtained at the end of each step is discussed and some suggestions are made as to what happens in these operations. It is shown the co-crystallization ensures a good dispersion of both compounds and is rather insensitive to the operating parameters tested. The maturing step allows some dissolution-recrystallization to occur thus intensifying the intimate contact between the two compounds. Addition of water is necessary to make maturing effective as this is governed by the transfer properties of the medium. The stripping step allows extraction of the residual solvent but also removes some of the Eflucimibe which is the main drawback of this final stage.  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