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   2273篇
  免费   85篇
  国内免费   27篇
耳鼻咽喉   100篇
儿科学   135篇
妇产科学   83篇
基础医学   129篇
口腔科学   59篇
临床医学   157篇
内科学   509篇
皮肤病学   33篇
神经病学   207篇
特种医学   90篇
外科学   569篇
综合类   36篇
预防医学   27篇
眼科学   66篇
药学   76篇
中国医学   1篇
肿瘤学   108篇
  2024年   1篇
  2023年   13篇
  2022年   18篇
  2021年   35篇
  2020年   27篇
  2019年   45篇
  2018年   50篇
  2017年   30篇
  2016年   79篇
  2015年   77篇
  2014年   86篇
  2013年   103篇
  2012年   143篇
  2011年   125篇
  2010年   97篇
  2009年   81篇
  2008年   165篇
  2007年   209篇
  2006年   185篇
  2005年   194篇
  2004年   163篇
  2003年   141篇
  2002年   132篇
  2001年   33篇
  2000年   22篇
  1999年   15篇
  1998年   20篇
  1997年   9篇
  1996年   13篇
  1995年   11篇
  1994年   9篇
  1993年   6篇
  1992年   2篇
  1991年   3篇
  1990年   7篇
  1989年   7篇
  1988年   7篇
  1987年   6篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1978年   1篇
  1977年   3篇
  1975年   1篇
  1966年   1篇
排序方式: 共有2385条查询结果,搜索用时 0 毫秒
71.
OBJECTIVE: The present study was carried out to evaluate the safety and immunogenicity of the Haemophilus influenzae type b-CRM197 (Hib-CRM197) conjugate vaccine in relation to the change of adjuvant from aluminum hydroxide to aluminum phosphate (AlPO4). METHODS: The present study was a clinical phase II, observer-blind, randomized, multicenter, controlled study. Subjects were healthy infants aged 6-12 weeks, eligible for expanded program of immunization (EPI) routine vaccination and admitted to Hacettepe University Department of Social Pediatrics and Gülveren Health Center, Ankara. A total of 520 healthy infants were randomized in a 2:2:1 ratio to receive at either Chiron Hib/AlPO4 vaccine or VaxemHib (aluminum hydroxide adjuvant) vaccine or HibTiter (no adjuvant). Vaccines were administered simultaneously with routine diphtheria, tetanus and pertussis (DTaP) and oral polio vaccine (OPV) vaccines at 2, 4 and 6 months of age. Blood samples for anti-plain polysaccharide (PRP) antibody measurement were collected before the first vaccination and 1 month after the last vaccination. After each vaccination parents filled out a diary for 7 days. RESULTS: Out of 520 subjects enrolled, 514 received three doses and were included for safety analysis. Local and systemic reactions occurred with low and similar frequencies in all groups. Only erythema was more common in Chiron Hib/AlPO4 vaccine (19, 10, 11% in Chiron Hib/AlPO4, VaxemHib and HibTiter, respectively, P < 0.05). Nine serious adverse events were reported in seven cases of which none were related to vaccines. A total of 504 subjects were included in the immunogenicity analysis. The three vaccines were highly immunogenic and equivalent in terms of percentage of acquisition of long-term protective levels. The anti-PRP geometric mean titers were 9.9, 8.3 and 5.14 micro g/mL, respectively (P < 0.05). CONCLUSIONS: The use of aluminum compounds adjuvants in Hib-CRM197 conjugate vaccines does not impact the safety profile, while it does increase the magnitude of anti-PRP antibody titers.  相似文献   
72.
BACKGROUND: Mumps vaccine has not yet been included in the routine vaccination programme, for this reason mumps is still one of the most common infections for children in Turkey. One of the major complication of mumps is meningoencephalitis, which although usually heals spontaneously, it may cause neurologic complications. METHODS: This study was undertaken to investigate epidemiologic and demographic characteristics in children with mumps and mumps meningoencephalitis and clinical/laboratory findings in children with mumps meningoencephalitis diagnosed over a 11 year period. A total of 2422 mumps and 135 mumps meningoencephalitis cases were covered in this study which constitutes one of the largest series of mumps meningoencephalitis in the literature. The mean age of mumps and mumps meningoencephalitis cases were 6.6 +/- 2.7 and 7.6 +/- 2.6 years, respectively. RESULTS: There was a male predominance both among the cases of mumps and mumps meningoencephalitis. The age and seasonal distributions were similar in the mumps and mumps meningoencephalitis groups. The most common symptoms of mumps meningoencephalitis were fever (97%), vomiting (94%) and headache (88.8%). The mean cerebrospinal fluid (CSF) total cell count and lymphocyte count were 540 +/- 460/mm(3) and 300 +/- 330/mm(3), respectively. The mean CSF protein and glucose levels were found to be 56.97 +/- 27.94 mg/dL and 53.67 +/- 15.46 mg/dL, respectively. The mean of CSF/blood glucose ratio was 0.53 +/- 0.16. The mean duration of hospitalization in mumps meningoencephalitis cases was found to be 5.1 +/- 2.4 days and this was longer in boys (P < 0.05). CONCLUSION: In patients with mumps meningoencephalitis, higher CSF protein levels and lower CSF glucose/blood glucose ratio were associated with longer hospitalization periods. There was no death.  相似文献   
73.
We report an elderly patient who developed severe delirium and extrapyramidal signs after initiation of lithium-olanzapine combination. On hospital admission, serum levels of lithium were found to be 3.0 mM/L which were far above toxic level. Immediate discontinuation of both drugs resulted in complete resolution of most of the symptoms except for perioral dyskinesia which persisted for three more months. We critically discussed the differential diagnosis of lithium intoxication and assessed confounding factors which induce delirium and extrapyramidal signs related with combination therapy of lithium and olanzapine.  相似文献   
74.
We investigated the brainstem integrity in children with primary nocturnal enuresis (PNE) using auditory brainstem responses (ABR), blink reflex and exteroceptive suppression of the masseter muscle. We examined 23 children with PNE (16 male, 7 female; mean age: 10.4 years) and 19 control subjects (11 male, 8 female; mean age: 11.8 years). ABR parameters such as wave latencies, amplitudes and interpeak latencies and blink reflex parameters such as R1 and R2 amplitude and latencies were not significantly different between the 2 groups. Although S2 parameters of the exteroceptive suppression of the masseter muscle were easily and completely obtained from the control subjects, in the PNE group S2 onset latency and duration were not recorded in 26% of the study children (n = 6) (P = 0.01). S2 duration time was significantly lowered in the enuretic group (left side: P = 0.001 and right side: P = 0.003). S2 duration time changes in the enuretic group supports a possible brainstem dysfunction in children with PNE.  相似文献   
75.
BACKGROUND: Nitric oxide (NO) has contradictory roles in the pathophysiology of allergic inflammation in both allergic rhinitis (AR) and asthma. Small amounts of NO produced by constitutive NO synthase (NOS) is anti-inflammatory, whereas large amounts produced by inducible NOS (iNOS) are proinflammatory. OBJECTIVE: To investigate the difference in constitutive endothelial NOS (eNOS) and iNOS expression in nonallergic and allergic mucosa and the possible relation of this to the coexistence of asthma in seasonal AR. METHODS: Seventeen patients (10 women and 7 men) with seasonal AR and 9 nonallergic patients (5 women and 4 men) with nasal septum deviation were enrolled. Inferior turbinate nasal biopsy specimens were obtained in all. Levels of eNOS and iNOS expressed as immunohistochemical scores (HSCOREs) were determined immunohistochemically from the specimens. RESULTS: The mean +/- SD HSCOREs for eNOS in patients with seasonal AR were not significantly different from those of the nonallergic controls (1.85 +/- 0.78 vs 1.63 +/- 0.54; P = .12). On the other hand, the mean +/- SD HSCOREs for iNOS were significantly higher in patients with seasonal AR (1.75 +/- 0.75 vs 0.71 +/- 0.6; P = .004). Furthermore, although eNOS expression was not different between seasonal AR patients with and without asthma, the mean +/- SD HSCOREs for iNOS were significantly higher in the patients with asthma (1.93 +/- 0.78 vs 1.65 +/- 0.55; P = .01). CONCLUSION: Increased expression of iNOS might have a role in the development of allergic inflammation in upper and lower airways and in comorbidity of AR and asthma.  相似文献   
76.
Anaplastic meningiomas that resemble sarcomas often reveal clues to their meningothelial differentiation or develop in a plausible setting that confirms their meningothelial origin. Malignant mesenchymal neoplasms without obvious evidence of meningothelial differentiation or origin are more likely to be true primary or metastatic sarcomas. Because of their clinical and biological differences, it is important to distinguish anaplastic meningioma from a sarcoma. We present a 67-year-old woman with multiple meningiomas, who developed a high-grade spindle cell tumor 6 months after the resection of a World Health Organization grade I meningioma. It was not clear whether this tumor represented a malignant transformation of meningioma or a primary sarcoma. Malignant transformation of a meningioma is exceptional within this short period and a coexisting sarcoma and meningioma are equally uncommon. Even though these malignant neoplasms are rare in general, they appear to be more prevalent in patients with multiple meningiomas including those with neurofibromatosis type 2.  相似文献   
77.
The objective of the present study was to develop 2-hydroxypropyl methacrylate-co-polyethylene methacrylate [p(HPMA-co-PEG–MEMA)] hydrogels that are able to efficiently entrap doxorubicin for the application of loco-regional control of the cancer disease. Systemic chemotherapy provides low clinical benefit while localized chemotherapy might provide a therapeutic advantage. In this study, effects of hydrogel properties such as PEG chains length, cross-linking density, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. In addition, the characterization of the hydrogel formulations was conducted with swelling experiments, permeability tests, Fourier transform infrared, SEM, and contact angle studies. In these drug-hydrogel systems, doxorubicin contains amine group that can be expected a strong Lewis acid–base interaction between drug and polar groups of PEG chains, thus the drug was released in a timely fashion with an electrostatic interaction mechanism. It was observed that doxorubicin release from the hydrogel formulations decreased when the density of cross-linking, and drug/polymer ratio were increased while an increase in the PEG chains length of the macro-monomer (i.e. PEG–MEMA) in the hydrogel system was associated with an increase in water content and doxorubicin release. The biocompatibility of the hydrogel formulations has been investigated using two measures: cytotoxicity test (using lactate dehydrogenase assay) and major serum proteins adsorption studies. Antitumor activity of the released doxorubicin was assessed using a human SNU398 human hepatocellular carcinoma cell line. It was observed that doxorubicin released from all of our hydrogel formulations which remained biologically active and had the capability to kill the tested cancer cells.  相似文献   
78.
To recognize the period of exaggerated cytokine response in patients with coronavirus disease 2019 (COVID-19) pneumonia, and to describe the clinical outcomes of using tocilizumab as a treatment option. The data of 12 adult COVID-19 pneumonia patients who were followed in the inpatient clinics of Biruni University Medical Faculty Hospital (Istanbul, Turkey) were retrospectively analyzed. Diagnostic tests, laboratory examinations, clinical findings, and computed tomography of the thorax imaging results were evaluated. A dramatic laboratory and clinical improvement was observed in 83% (10 out of 12) of patients after tocilizumab. In 17% (2 out of 12) of our patients, short-term ventilator support was required in the intensive care unit. The longest hospital stay was 18 days. However, in the end, all of our patients were discharged home with good health. Although arterial oxygen saturations (87.58 ± 3.12%) dropped in room air in the pre-tocilizumab period, post-tocilizumab they normalized in all patients (94.42 ± 1%). None of them had fever after tocilizumab treatment and the levels of C-reactive protein (13.08 ± 12.89) were almost within normal limits. Eosinophil values were quite low at the time of diagnosis (10 ± 17.06), but increased significantly post-tocilizumab (155.33 ± 192.69). There is currently no proven treatment for COVID-19 induced by novel coronavirus SARS-CoV-2. Based on our experience with twelve adult COVID-19 pneumonia patients, we can say that tocilizumab, an IL-6 inhibitor, is more beneficial in preventing the damage caused by excessive cytokine response in the body if administered at the right time and provides clinical and radiological recovery.  相似文献   
79.
Paraoxonase-1 is an esterase enzyme and it has 3 types of activity, namely paraoxonase, arylesterase, and diazoxonase. It has been reported that paraoxonase-1 deficiency is related to increased susceptibility to development of atherosclerosis and cardiovascular disease. The aim of this study was to investigate serum paraoxonase and arylesterase activities in children with iron deficiency anemia and vitamin B(12) deficiency anemia. Thirty children with iron deficiency anemia, 30 children with vitamin B(12) deficiency anemia, and 40 healthy children aged 6 months to 6 years were enrolled in this study. Serum paraoxonase and arylesterase activities were measured with a spectrophotometer by using commercially available kits. Mean paraoxonase and arylesterase activities in vitamin B(12) deficiency anemia group (103 ± 73 and 102 ± 41 U/L, respectively) were significantly lower than mean activities of control group (188 ± 100 and 147 ± 34 U/L, respectively; P < .001 for both) and iron deficiency anemia group (165 ± 103 and 138 ± 39 U/L, respectively; P < .05, P < .001), whereas there were no significant differences between iron deficiency anemia and control groups (P > .05). Paraoxonase and arylesterase activities significantly increased after treatment with vitamin B(12) in vitamin B(12) deficiency anemia; however, there were no significant changes in the activities of these enzymes after iron treatment in iron deficiency anemia group. Important correlations were found between vitamin B(12) levels and both paraoxonase and arylesterase activities (r = .367, P < .001; r = .445, P < .001). Our results suggest that vitamin B(12) deficiency anemia causes important reductions in paraoxonase and arylesterase activities, and after vitamin B(12) therapy the activities of these enzymes returned to near-normal levels.  相似文献   
80.
Despite constant contact with the large population of commensal bacteria, the colonic mucosa is normally hyporesponsive to these potentially proinflammatory signals. Here we report that the single immunoglobulin IL-1 receptor-related molecule (SIGIRR), a negative regulator for Toll-IL-1R signaling, plays a critical role in gut homeostasis, intestinal inflammation, and colitis-associated tumorigenesis by maintaining the microbial tolerance of the colonic epithelium. SIGIRR-deficient (Sigirr(-/-)) colonic epithelial cells displayed commensal bacteria-dependent homeostatic defects, as shown by constitutive upregulation of inflammatory genes, increased inflammatory responses to dextran sulfate sodium (DSS) challenge, and increased Azoxymethane (AOM)+DSS-induced colitis-associated tumorigenesis. Gut epithelium-specific expression of the SIGIRR transgene in the SIGIRR-deficient background reduced the cell survival of the SIGIRR-deficient colon epithelium, abrogated the hypersensitivity of the Sigirr(-/-) mice to DSS-induced colitis, and reduced AOM+DSS-induced tumorigenesis. Taken together, our results indicate that epithelium-derived SIGIRR is critical in controlling the homeostasis and innate immune responses of the colon to enteric microflora.  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