全文获取类型
收费全文 | 2078篇 |
免费 | 161篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 71篇 |
妇产科学 | 136篇 |
基础医学 | 287篇 |
口腔科学 | 37篇 |
临床医学 | 130篇 |
内科学 | 561篇 |
皮肤病学 | 28篇 |
神经病学 | 166篇 |
特种医学 | 92篇 |
外国民族医学 | 1篇 |
外科学 | 282篇 |
综合类 | 24篇 |
预防医学 | 87篇 |
眼科学 | 35篇 |
药学 | 119篇 |
中国医学 | 4篇 |
肿瘤学 | 150篇 |
出版年
2023年 | 29篇 |
2022年 | 21篇 |
2021年 | 73篇 |
2020年 | 44篇 |
2019年 | 53篇 |
2018年 | 60篇 |
2017年 | 61篇 |
2016年 | 51篇 |
2015年 | 76篇 |
2014年 | 102篇 |
2013年 | 120篇 |
2012年 | 127篇 |
2011年 | 134篇 |
2010年 | 94篇 |
2009年 | 61篇 |
2008年 | 122篇 |
2007年 | 130篇 |
2006年 | 119篇 |
2005年 | 145篇 |
2004年 | 103篇 |
2003年 | 99篇 |
2002年 | 85篇 |
2001年 | 25篇 |
2000年 | 19篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 9篇 |
1996年 | 16篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 20篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 18篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1969年 | 4篇 |
1968年 | 6篇 |
排序方式: 共有2254条查询结果,搜索用时 15 毫秒
1.
Sania Amr Magdy Garas Dina N. K. Boulos Doa’a A. Saleh Irene A. Jillson Christopher A. Loffredo 《Journal of substance use》2019,24(3):341-345
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood. 相似文献
2.
Mokhtar Elhakim Magdy Nafie Khalaf Mahmoud Azza Atef 《Journal canadien d'anesthésie》2002,49(9):922-926
PURPOSE: The combination of antiemetic drugs could be a solution to prevent severe postoperative nausea and vomiting (PONV). The aim of this randomized double blind, dose-ranging study was to determine the minimum single effective dose of dexamethasone combined with ondansetron for the prevention of PONV in patients undergoing laparoscopic cholecystectomy. METHODS: One hundred eighty patients were allocated randomly to one of six groups to receive saline (P group), ondansetron 4 mg (O group), or ondansetron 4 mg and dexamethasone at doses of 2 mg (OD2 group), 4 mg (OD4 group), 8 mg (OD8 group), and 16 mg (OD16 group). A standardized general anesthetic was used. All episodes of PONV during the intervals of zero to six hours, 6-12 hr and 12-24 hr after surgery were evaluated using a numeric scoring system. Mean visual analogue scale pain scores at rest and on movement, the time to first demand of analgesia, total analgesic consumption in 12 hr epochs, duration of hospital stay, and side effects were recorded. RESULTS: The incidence of PONV in the OD8 (16%) and OD16 (16%) groups was lower than in the 83% (P < 0.001) and O groups (50%) at the 12-24 hr epoch (P < 0.05). There were no differences in antiemetic effect between the O, OD2 and OD4 groups and between the OD8 and OD16 groups. Pain scores, total analgesic consumption, duration of hospital stay and side effects were similar among groups. CONCLUSION: Our results suggest that 8 mg is the minimum dose of dexamethasone that, combined with ondansetron 4 mg will effectively prevent PONV in patients undergoing laparoscopic cholecystectomy. 相似文献
3.
Gad Degani Rakefet Sharon Michael Warburg 《General and comparative endocrinology》1997,106(3):356-360
Gonadal steroid levels were determined in the ovary ofSalamandra salamandra infraimmaculataduring the reproductive cycle in populations from a xeric region in northern Israel. Varying proportions of previtellogenic and vitellogenic oocytes were present throughout the year, and mature oocytes were present in winter and spring. The numbers of mature oocytes were greater between December and April, after parturition. The levels of 17β-estradiol and testosterone rose during oocyte vitellogenesis and maturation. Levels of progesterone and 17α-hydroxy progesterone appeared to be related to the level of vitellogenesis. Gravid females contained greater quantities of all four steroids than did nongravid females. 相似文献
4.
Adel M. Mansour Robert W. Frenck Jr. Toni Darville Isabelle A. Nakhla Thomas F. Wierzba Yehia Sultan Magdy I. Bassiouny Kathryn McCarthy Richard F. Jacobs 《Clinical and Vaccine Immunology : CVI》2005,12(2):363-365
Cerebrospinal fluid gamma interferon (IFN-γ) and interleukin-10 levels in 39 patients with tuberculous meningitis were serially measured. Cytokine levels did not predict intracranial granuloma (IG) development, but IFN-γ levels in the top quartile after 1 month of therapy were highly associated (odds ratio = 18) with detection of an IG by computed tomography scanning. 相似文献
5.
Diagnosis of scaphoid fractures:A prospective multicenter study of 1,052 patients with 160 fractures
Bo Munk Johnny Fr kj r Claus Falck Larsen Hans Gad Johannsen Lars Lundager Rasmussen Annette Edal Lilla Demeney Rasmussen 《Acta orthopaedica》1995,66(4):359-360
In a prospective multicenter study of 1,052 patients with clinical signs of a scaphoid fracture, mammo-graphic films and fine intensifying screens were used at the radiographic examination. 5 standardized projections including 3 special projections focused on the scaphoid were taken. 150 fractures were diagnosed at the first examination but in 10 cases the fracture was first diagnosed at a second radiographic examination after 10-14 days.
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections. 相似文献
6.
7.
In 224 consecutive patients with hormone-resistant prostatic cancer referred to 2 European Cancer Centres for palliation of painful bone metastases the one year survival for all patients was 24% (2-year survival: 7%). The median survival was 8 months. In univariate analyses the following prognostic factors were identified: performance status, serum creatinine, alkaline phosphatase, duration of response to primary hormone treatment, degree of bone scan involvement and hemoglobin. Multivariate analyses confirmed the four first parameters to be independent factors. A prognostic model was established (no or one risk factors vs 2 risk factors vs 3 or 4 risk factors) based on performance status, creatinine, alkaline phosphatase and hormone response duration. The median survival of these groups was 10 months, 6 months and 3 months, respectively. This model proved to be discriminative in an external data set of 214 patients with hormone-resistant prostatic cancer entered in two prospective trials. The above differences in outcome between readily and simply defined prognostic groups are greater than the differences one can realistically hope to produce using new treatment strategies. These prognostic factors should be taken into account both in the design and interpretation of clinical studies dealing with the treatment of hormone-resistant progressing prostatic cancer and painful bone metastases. 相似文献
8.
Maya Koronyo-Hamaoui Eva Gak Daniel Stein Amos Frisch Yardena Danziger Shani Leor Elena Michaelovsky Neil Laufer Cynthia Carel Silvana Fennig Marc Mimouni Alan Apter Boleslav Goldman Gad Barkai Abraham Weizman 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2004,(1):76-80
The human small-conductance Ca(2+)-activated potassium channel gene KCNN3 has been involved in mechanisms underlying neuronal function and plasticity. A multiallelic CAG repeat polymorphism within the KCNN3 has been associated with schizophrenia and bipolar disorder. We have previously reported in a family-based study that longer CAG repeats are preferentially transmitted to patients with anorexia nervosa (AN). The present study extends the analysis of KCNN3 allele distribution to a larger series of AN female patients and control groups, incorporating information on ethnicity and co-morbidities associated with AN. The data analysis is presented while considering separately the two alleles of each individual, namely a minor (shorter) and a major (longer) allele. This study has found that the KCNN3 allele distribution in the general Israeli population does not differ significantly in at least four Jewish ethnic groups of Ashkenazi, North African, Iraqi, and Yemenite origin. These have been used as control groups in a matched case-control analysis that has demonstrated a significant over-representation of KCNN3 alleles with longer CAG repeats among AN patients (P < 0.001 for the major allele and P = 0.035 for allele sum). Under dichotomization, a significantly higher prevalence of the L allele (>19 repeats) has been observed among AN patients (P < 0.001). While considering AN and co-morbid phenotypes, a tendency towards longer (L) alleles has been observed in the subset of patients with obsessive-compulsive disorder (OCD) co-morbidity. These findings further implicate KCNN3 as a significant contributor to predisposition to AN. 相似文献
9.
Hussein M. M. Hassab-El-Naby Qasem A. Alsaleh Magdy A. Fathallah 《Pediatric dermatology》1996,13(2):148-150
Abstract: A child had cerebral palsy and linear and whorled nevoid hypermelanosis on the right side of his body. He had spasticity and wasting in both lower limbs, with electroencephalographic changes and brain abnormalities on computerized tomographic scan. Chromosomal study of peripheral blood leukocytes found a normal male karyotype. The pathogenesis of this condition is still unclear. 相似文献
10.
S. Shahabuddin I. Al-Ayed M. O. Gad El-Rab M. I. Qureshi 《Clinical and Vaccine Immunology : CVI》1998,5(5):632-635
The age-related changes in absolute and percentage values of lymphocyte subsets in the peripheral blood of healthy children of different ages (1 month to 13 years) were studied by flow cytometry. The absolute and percentage values for most lymphocyte subpopulations differed substantially with age. Comparisons among age groups from infants through adults revealed progressive declines in the absolute numbers of leukocytes, total lymphocytes, and T, B, and natural killer (NK) cells. The percentages of T cells increased with age. Within the T-lymphocyte population, the CD8+ subset increased but the CD4+ subset decreased, resulting in a declining CD4+/CD8+ ratio. The percentage of B cells declined, but that of NK cells remained unchanged. The percentage of HLA-DR+ T cells increased over time, but their number changed inconsistently. Our findings confirm and extend earlier reports on age-related changes in lymphocyte subpopulations. These data should be useful in the interpretation of disease-related changes, as well as therapy-dependent alterations, in lymphocyte subsets in children of different age groups. 相似文献