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   441篇
  免费   27篇
耳鼻咽喉   11篇
儿科学   38篇
妇产科学   4篇
基础医学   35篇
口腔科学   10篇
临床医学   30篇
内科学   56篇
皮肤病学   11篇
神经病学   30篇
特种医学   12篇
外科学   35篇
综合类   9篇
一般理论   10篇
预防医学   35篇
眼科学   19篇
药学   39篇
中国医学   2篇
肿瘤学   82篇
  2024年   1篇
  2023年   1篇
  2022年   9篇
  2021年   24篇
  2020年   13篇
  2019年   17篇
  2018年   16篇
  2017年   22篇
  2016年   14篇
  2015年   9篇
  2014年   22篇
  2013年   21篇
  2012年   54篇
  2011年   39篇
  2010年   20篇
  2009年   14篇
  2008年   34篇
  2007年   19篇
  2006年   22篇
  2005年   17篇
  2004年   12篇
  2003年   3篇
  2002年   14篇
  2001年   1篇
  2000年   6篇
  1999年   3篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1993年   1篇
  1990年   5篇
  1989年   5篇
  1988年   3篇
  1987年   1篇
  1981年   1篇
  1976年   2篇
  1975年   2篇
  1974年   5篇
  1973年   4篇
  1970年   2篇
  1969年   2篇
  1968年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有468条查询结果,搜索用时 0 毫秒
21.
Immigrant parents and their U.S.-born children may experience stressful family conflicts over the disparate sociocultural norms of the United States and their country of origin. Such stresses may heighten adolescents' vulnerability to drug abuse. This article documents the extent of drug use in a sample of 200 U.S.-born Asian Indian adolescents. According to the study participants' self-reports on lifetime use, 28 percent had used alcohol on at least one occasion, 16.5 percent had used cigarettes, and 2.5 percent had used marijuana. Adolescents who placed importance on their parents' drug abuse prevention messages tended not to use drugs. The implications of the study's findings for drug abuse assessment, treatment, and prevention are discussed.  相似文献   
22.
23.
24.
25.
Sebaceous carcinoma of the eyelid is an uncommon tumour with unusual modes of presentation. It can remain occult at the primary site, without producing any mass, masquerading as chronic blepharoconjunctivitis, while setting up metastases in the regional lymph nodes especially in the pre-auricular group. We report here a case that not only masqueraded as chronic blepharoconjunctivitis with nodal metastases from an 'unknown primary' in the neck, but whose tumour spread in a pagetoid manner along the nasolacrimal duct producing a nasal tumour that was believed to be the 'unknown primary'. This case emphasizes the need for ophthalmologists, ENT surgeons and pathologists to keep sebaceous carcinoma in mind while evaluating patients with chronic blepharoconjunctivitis and cervical node metastases from 'unknown primary'. Histological clues for picking up a sebaceous carcinoma at a metastatic site include a tumour with comedo or ductal growth pattern and intracytoplasmic lipid.  相似文献   
26.
27.
Reliable surveillance models are an important tool in public health because they aid in mitigating disease outbreaks, identify where and when disease outbreaks occur, and predict future occurrences. Although many statistical models have been devised for surveillance purposes, none are able to simultaneously achieve the important practical goals of good sensitivity and specificity, proper use of covariate information, inclusion of spatio-temporal dynamics, and transparent support to decision-makers. In an effort to achieve these goals, this paper proposes a spatio-temporal conditional autoregressive hidden Markov model with an absorbing state. The model performs well in both a large simulation study and in an application to influenza/pneumonia fatality data.  相似文献   
28.
We have studied Pulmonary Function Tests (PFTs) namely Vital Capacity (VC). Forced Vital Capacity (FVC), and Forced Expiratory Volume in First Second (FEV1). Forced Expiratory Flow(FEF 25-50%) in 1200 elderly subjects above 60 years of age of which 570 were females and 630 males. Mean age was 69.22 +/- 5.57 years in males and 68.77 +/- 5.44 in females. The mean value of ventilatory parameters were as follows-1) VC 2.99 +/- 0.5 lt in males and 1.89 +/- 0.29 lt in females. 2) FVC 2.69 +/- 0.58 lt. in males and 1.76 +/- 0.21 lt in females. 3) FEV1/FVC% 83.82 +/- 10.62% in males and 83.37 +/- 11.93% in females. 4) FEF 25-75% was 2.81 +/- 1.20 lt/sec in males and 2.13 +/- 1.27 lt/sec. Physical as well as ventilatory parameters were less in females than for males. The correlation of age with VC and FEV1 was highly significant (P < 0.01) but with FVC was not significant (P > 0.05). The correlation of height, weight and body surface area was not significant with any ventilatory parameter (P > 0.05). Multiple regression equations for VC, FVC and FEV1 were formulated for males and females taking height and age as variables. The predicted values correlated excellently with observed values.  相似文献   
29.
Pancreatic cancer is a lethal disease characterized by multiple disease-related symptoms. Chemoradiation therapy is a standard of treatment for locally advanced pancreatic cancer. Although shown to prolong survival, there is little information about treatment-related symptoms or the palliative benefits of chemoradiation. We assessed symptoms of patients with locally advanced pancreatic cancer receiving chemoradiation to determine the prevalence, and co-occurrence, of symptoms and to identify the extent to which symptoms interfered with function. Forty-eight patients were treated with chemoradiation on a Phase I protocol. Patients received radiotherapy (50.4 Gy in 28 fractions), capecitabine (median dose 825 mg/m(2) twice daily), and bevacizumab (2.5-10 mg/kg). Symptom severity and its interference with function were prospectively assessed (at presentation, during, and after chemoradiation) in 43 consenting patients using the M.D. Anderson Symptom Inventory. Results showed that 95% of patients reported at least one of the 13 symptoms assessed at presentation. The most commonly reported symptoms of moderate to severe (>or=5 on a 0-10 scale) intensity at presentation were lack of appetite (24%), pain (19%), fatigue (19%), and sleep disturbance (10%). We observed an increase in patients reporting moderate to severe fatigue, nausea, and sleep disturbance during chemoradiation. McNemar tests for paired binary observations showed the proportion of patients reporting moderate to severe symptoms significantly (P<0.001) decreased after chemoradiation at 94 days follow-up (lack of appetite=7%, pain=7%, fatigue=13%, sleep disturbance=7%). This study demonstrates the feasibility and usefulness of symptom assessment in chemoradiation protocols. Future studies with larger cohorts are needed to further characterize multiple symptoms associated with chemoradiation.  相似文献   
30.
Chemical pH-oscillators provide a potential means for modulating the delivery of acidic or basic drugs across lipophilic membranes. Previous attempts to exploit this notion were not completely successful due to quenching of the pH oscillator in the presence of the drug, most likely by a buffering mechanism. Here we show that multiple, periodic pulses of drug flux across a membrane can be achieved when the concentration of drug is sufficiently low. Advantage is taken of a pH oscillator system whose periodicity is slower than that of previously considered oscillators.  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