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   1147篇
  免费   67篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   7篇
妇产科学   86篇
基础医学   129篇
口腔科学   2篇
临床医学   194篇
内科学   194篇
皮肤病学   6篇
神经病学   107篇
特种医学   28篇
外科学   167篇
综合类   27篇
一般理论   1篇
预防医学   52篇
眼科学   4篇
药学   83篇
中国医学   24篇
肿瘤学   102篇
  2024年   1篇
  2023年   6篇
  2022年   9篇
  2021年   23篇
  2020年   17篇
  2019年   21篇
  2018年   49篇
  2017年   28篇
  2016年   19篇
  2015年   40篇
  2014年   50篇
  2013年   74篇
  2012年   104篇
  2011年   86篇
  2010年   46篇
  2009年   55篇
  2008年   82篇
  2007年   68篇
  2006年   67篇
  2005年   68篇
  2004年   39篇
  2003年   37篇
  2002年   30篇
  2001年   30篇
  2000年   34篇
  1999年   16篇
  1998年   8篇
  1997年   10篇
  1996年   5篇
  1995年   6篇
  1993年   3篇
  1992年   18篇
  1991年   10篇
  1990年   9篇
  1989年   9篇
  1988年   6篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   8篇
  1982年   1篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
排序方式: 共有1217条查询结果,搜索用时 31 毫秒
71.
OBJECTIVE: To describe growth before and after menarche. DESIGN: Nine hundred five fourth grade school girls were identified as a closed cohort from the first semester of 1993 for the observational study of the onset of menarche and its predictive factors. SETTINGS: Eight elementary schools in Taipei City and Taipei County, Taiwan. MAIN OUTCOME MEASURES: Data were collected from self-administered questionnaires and school records. Height and weight were measured in September, January, February, and June, or only in September and February of each year. RESULTS: All subjects remained in the cohort until sixth grade, 410 of whom had their first menstruation before graduating from elementary school. Height, weight, and body mass index (calculated as weight in kilograms divided by the square of height in meters) at each time point were plotted against 2 time scales: chronological age and time from the onset of menarche. Growth velocity of height and weight across the onset of menarche was assessed with slope change using the mixed-effect model analysis. CONCLUSIONS: The results support the hypothesis that height velocity reaches a peak 1 year before menarche but height velocity stopped increasing within 1 year after menarche. The change in weight velocity reveals no obvious growth spurt at age of menarcheal onset.  相似文献   
72.
OBJECTIVE: To determine whether a low initial dosage of cetrorelix acetate could prevent a premature luteinizing hormone (LH) surge in women undergoing controlled ovarian stimulation. METHOD: Treatment with a recombinant follicle stimulating hormone was started on Day 3 of the menstrual cycle, and 0.125 mg of cetrorelix was injected daily from Day 5 of the ovarian stimulation until the diameter of the dominant follicle reached at least 16 mm. The dosage was then doubled and maintained at 0.250 mg/day until the day before the injection of human chorionic gonadotropin. RESULT: There was a significant decrease in serum LH concentration 1 day after doubling the cetrorelix dosage, and the LH concentration remained low during the follicular phase. Clinical pregnancy occurred in 18 women (42.8%), with 2 intrauterine fetal deaths before the 12th week. CONCLUSION: Increasing the cetrorelix dosage from 0.125 to 0.250 mg/day when the follicular size is appropriate can prevent a premature LH surge.  相似文献   
73.
Prevention of pulmonary morbidity for patients with neuromuscular disease   总被引:7,自引:0,他引:7  
Tzeng AC  Bach JR 《Chest》2000,118(5):1390-1396
STUDY OBJECTIVE: To evaluate the effects of a respiratory muscle aid protocol on hospitalization rates for respiratory complications of neuromuscular disease. DESIGN: A retrospective cohort study. METHODS: A home protocol was developed in which oxyhemoglobin desaturation was prevented or reversed by the use of noninvasive intermittent positive-pressure ventilation and manually and mechanically assisted coughing as needed. The patients who had more than one episode of respiratory failure before having access to the protocol were considered to have had preprotocol periods (group 1). Other patients were given access to the protocol when their assisted peak cough flows decreased to < 270 L/min before any episodes of respiratory distress (group 2). The number of hospitalizations and days hospitalized were compared longitudinally for preprotocol and protocol access periods (group 1). In addition, avoided hospitalizations were identified as "episodes" of need for continuous ventilatory support and desaturations reversed by assisted coughing that were managed at home. Data were segregated by access to protocol and by extent of baseline ventilator use. RESULTS: Of the 47 group 1 patients with preprotocol periods who have subsequently had episodes, 10 had episodes before requiring ongoing ventilator use. They had 1.06 +/- 0.84 preprotocol hospitalizations per year per patient and 20.76 +/- 36.01 hospitalization days per year per patient over 3.42 +/- 3.36 years per patient vs 0.03 +/- 0.11 hospitalizations per year per patient and 0.06 +/- 0.20 hospitalization days per year per patient with protocol use over 1.94 +/- 0.74 years per patient. Of these 47 group 1 patients, 33 eventually required part-time ventilatory aid and, using the protocol as needed, had 0.08 +/- 0.17 hospitalizations per year per patient and 1.43 +/- 3.71 hospitalization days per year per patient over 3.91 +/- 3.50 years per patient, as opposed to 1.40 +/- 1.96 hospitalizations per year per patient and 20.14 +/- 41.15 hospitalization days per year per patient preprotocol and preventilator use over 5.89 +/- 6.89 years per patient. Twelve patients in group 1 eventually required continuous noninvasive ventilation and, using the protocol as needed, had 0.07 +/- 0.14 hospitalizations per year per patient and 0.39 +/- 0.73 hospitalization days per year per patient over 5.35 +/- 5.10 years per patient by comparison with 0.97 +/- 0.74 hospitalizations per year per patient and 10.39 +/- 8.66 hospitalization days per year per patient over 2.18 +/- 1.91 years per patient preprotocol and preventilator use. For the 94 patients overall when having access to the protocol, 1.02 +/- 0.99 hospitalizations per year per patient were avoided by 14 patients before requiring ongoing ventilator use over 4.82 +/- 1.61 years, 0.99 +/- 1.12 hospitalizations per year per patient were avoided by 73 part-time ventilator users over 3.21 +/- 3.15 years, and 0.80 +/- 0.85 hospitalizations per year per patient were avoided by 31 full-time ventilator users over 4.78 +/- 4.88 years. All preprotocol and protocol rate comparisons were statistically significant at p < 0.004. CONCLUSION: Patients have significantly fewer hospitalizations per year and days per year when using the protocol as needed than without the protocol. The use of inspiratory and expiratory aids can significantly decrease hospitalization rates for respiratory complications of neuromuscular disease.  相似文献   
74.
Haplotypes incorporate more information about the underlying polymorphisms than do genotypes for individual SNPs, and are considered as a more informative format of data in association analysis. To model haplotypes requires high degrees of freedom, which could decrease power and limit a model's capacity to incorporate other complex effects, such as gene-gene interactions. Even within haplotype blocks, high degrees of freedom are still a concern unless one chooses to discard rare haplotypes. To increase the efficiency and power of haplotype analysis, we adapt the evolutionary concepts of cladistic analyses and propose a grouping algorithm to cluster rare haplotypes to the corresponding ancestral haplotypes. The algorithm determines the cluster bases by preserving common haplotypes using a criterion built on the Shannon information content. Each haplotype is then assigned to its appropriate clusters probabilistically according to the cladistic relationship. Through this algorithm, we perform association analysis based on groups of haplotypes. Simulation results indicate power increases for performing tests on the haplotype clusters when compared to tests using original haplotypes or the truncated haplotype distribution.  相似文献   
75.
Certain linear 4-anilinofuro[2,3-b]quinoline and angular 4-anilinofuro[3,2-c]quinoline derivatives were synthesized and evaluated in vitro against the full panel of NCI's 60 cancer cell lines. For the linear 4-anilinofuro[2,3-b]quinoline derivatives, 1-[4-(furo[2,3-b]quinolin-4-ylamino)phenyl]ethanone (5a) is the most cytotoxic with a mean GI50 value of 0.025 microM. Substitution at either furo[2,3-b]quinoline ring (2a, 2b, and 5b) or 4-anilino moiety (3-7) led to a decrease of cytotoxicity. For the angular 4-anilinofuro[3,2-c]quinoline derivatives, (E)-1-[3-(furo[3,2-c]quinolin-4-ylamino)phenyl]ethanone oxime (14a) exhibited potent inhibitory activities on UO-31, UACC-257, and UACC-62, with GI50 values of 0.03,<0.01, and<0.01 microM respectively. The same cytotoxicity profile was observed for its methyl counterpart, 14b, in which the GI50 values against UO-31, UACC-257, and UACC-62 was<0.01, 0.04 and<0.01 microM respectively. These results deserve full attention especially because 14a and 14b are relatively non-cytotoxic with the mean GI50 value of 7.73 and 8.91 microM respectively.  相似文献   
76.
Adenosine triphosphate (ATP) has been shown to induce programmed cell death in various systems. However, little is known about the effect of ATP on human granulosa-luteal cells (hGLCs). The present study was designed to examine the effect of ATP on the activation of the caspase signaling pathway and its role in inducing programmed cell death. Human GLCs were collected from patients undergoing in vitro fertilization programs, and then were cultured in FBS-supplemented DMEM for 3 days prior to our studies. To examine the dose-response relationship, hGLCs were treated with increasing concentrations of ATP (10 microM, 100 microM, 1 mM or 10 mM) for 24 hours. For time-course experiments, hGLCs were treated with 10 mM ATP for 6, 12, or 24 hours. Western blot analysis was performed using antibodies against the pro- and active forms of caspase-3, -9, or PARP. To quantify the induction of apoptosis, DNA fragmentation was measured using the cell death detection enzyme-linked immunosorbent assay. To examine the effect of human chorionic gonadotropin (hCG) in protecting cells from apoptosis, hGLCs were treated with 10 IU hCG in the presence of 10 mM ATP for 12 hours. It was demonstrated that ATP was capable of inducing DNA fragmentation in a dose- and time-dependent manner. Furthermore, Western blot analysis, which detected the pro- and active forms of caspase-3, or PARP, demonstrated that ATP activated the caspase-signaling pathway, leading to the proteolytic conversion of pro-caspase-3 to active caspase-3, and the subsequent cleavage of the caspase substrate PARP. Based on our observation, caspase-9 was not triggered by ATP. Interestingly, hCG attenuated the effect of ATP in activating the caspase signaling pathway. To our knowledge, this is the first demonstration of the ATP-induced activation of the caspase signaling pathway in the human ovary. These results support the notion that the caspase-signaling pathway is involved in mediating ATP actions in the human ovary.  相似文献   
77.
Sleep is a basic human need. A good night's sleep shapes our physical and mental health. Female nurses experience particularly complex sleep disturbance problems because of after working rotating shifts, as well as because of the effects of the female reproductive hormones. Both issues present a challenge to the understanding of female nurses' sleep. This paper summarizes the existing knowledge about sleep in women, including shift workers in relation to their reproductive status, and introduces practical sleep hygiene concepts and strategies for female nurses.  相似文献   
78.
The ethnographic study on which this report is based investigated experiences among patients, their families, friends, colleagues, and health professionals following a suicide attempt. Misunderstanding and ineffective treatment are often based on different explanations of suicide held by patients, their families, and health professionals, even when they share culture and language. In this report we describe how suicide is perceived by psychiatric team members in one regional teaching hospital in northern Taiwan. Twenty-two staff members of the Department of Psychiatry participated in this study. "Making a diagnosis" characterized the psychiatric subculture around the care of suicidal patients. In addition, mental health professionals tended to differentiate the patient's condition through three main avenues: (a) psychotic symptoms versus personality problems, (b) low IQ and high educational level, and (c) high versus low lethality of method. These findings suggest that mental health professionals need to bridge the gap between their knowledge and understanding of suicide and patients' and patients' families' expectations for care and treatment.  相似文献   
79.
80.
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