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   28155篇
  免费   1775篇
  国内免费   115篇
耳鼻咽喉   286篇
儿科学   789篇
妇产科学   593篇
基础医学   4244篇
口腔科学   2528篇
临床医学   2253篇
内科学   5676篇
皮肤病学   601篇
神经病学   2117篇
特种医学   615篇
外国民族医学   1篇
外科学   3086篇
综合类   354篇
一般理论   7篇
预防医学   3215篇
眼科学   351篇
药学   2019篇
中国医学   281篇
肿瘤学   1029篇
  2023年   277篇
  2022年   657篇
  2021年   1064篇
  2020年   734篇
  2019年   923篇
  2018年   1059篇
  2017年   791篇
  2016年   807篇
  2015年   943篇
  2014年   1217篇
  2013年   1452篇
  2012年   2208篇
  2011年   2432篇
  2010年   1281篇
  2009年   955篇
  2008年   1603篇
  2007年   1506篇
  2006年   1381篇
  2005年   1137篇
  2004年   987篇
  2003年   886篇
  2002年   786篇
  2001年   550篇
  2000年   605篇
  1999年   486篇
  1998年   185篇
  1997年   127篇
  1996年   136篇
  1995年   121篇
  1994年   103篇
  1993年   88篇
  1992年   218篇
  1991年   205篇
  1990年   197篇
  1989年   195篇
  1988年   185篇
  1987年   141篇
  1986年   127篇
  1985年   130篇
  1984年   106篇
  1983年   84篇
  1979年   85篇
  1978年   78篇
  1977年   49篇
  1975年   56篇
  1974年   62篇
  1973年   62篇
  1970年   60篇
  1969年   47篇
  1967年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
F. Calais da Silva 《Infection》1992,20(Z3):S221-S223
The aim of prophylactic antibiotic therapy in urological surgery is the prevention of local or systemic infections. The authors treated 100 patients prophylactically; 62 were treated with amikacin and 38 with cefotaxime. Of the 62 patients treated with amikacin, 18 had infectious complications. Of the 38 patients treated with cefotaxime, ten had infectious complications. We conclude that in the Hospital do Desterro the incidence of infectious complications is high, despite antibiotic prophylaxis.Das Ziel der Antibiotikaprophylaxe bei urologischen Operationen ist die Verhinderung von lokalen und systemischen Infektionen. Die Autoren führten bei 100 Patienten eine Prophylaxe durch; 62 Patienten wurden mit Amikacin und 38 Patienten mit Cefotaxim behandelt. Von den 62 mit Amikacin behandelten Patienten hatten 18 und von den 38 mit Cefotaxim behandelten Patienten hatten zehn Patienten infektiöse Komplikationen. Daraus ergibt sich, daß trotz Antibiotikaprophylaxe das Auftreten infektiöser Komplikationen im Hospital do Desterro hoch ist.
Dr.Calais da Silva's discussion could not be presented during the meeting because of an unforeseen event, but the kindly provided us with this discussion.  相似文献   
52.
Wilson's disease (WD) is a rare liver-based disorder of copper metabolism. Prognostic criteria described by our group in 1986 to predict death without transplantation have not been universally validated. The clinical features of 88 children were reviewed, retrospectively in 74 and prospectively in 14. Data from the retrospectively recruited patients that died or survived on long-term chelation were used to evaluate the validity of our old scoring system and to devise a new prognostic index, then assessed in the 14 prospectively recruited patients. Using the old scoring system, 5 children scoring > or = 7, the cutoff value for death without transplantation, survived, whereas 4 scoring < or = 7 died (sensitivity 87% and specificity 90%). A new index based on serum bilirubin, international normalized ratio, aspartate aminotransferase (AST), and white cell count (WCC) at presentation identified a cutoff score of 11 for death and proved to be 93% sensitive and 98% specific, with a positive predictive value of 88%. When the new index was evaluated prospectively in 14 patients, it predicted the need for transplantation in only the 4 who required it, although 1 child with a score of 11 survived on medical treatment. In conclusion, the new Wilson Index is more sensitive and specific in predicting mortality without transplantation than the old scoring system, but needs to be validated in a larger number of patients.  相似文献   
53.
PURPOSE: Postoperative nausea and vomiting (PONV) is the most common postoperative complication after surgery and general anesthesia. PONV occurs primarily within the first 24 hours and can lead to significant morbidity, delayed hospital discharge, increased hospital costs and perhaps most importantly, poor patient satisfaction. We sought, in this study, to determine the prevalence of PONV and to identify risk factors in patients who underwent orthognathic surgery. PATIENTS AND METHODS: We conducted a retrospective cross-sectional analytic survey of 553 consecutive patients over 14 years of age, who underwent maxillary and/or mandibular osteotomies at Kaiser Permanente Hospital (Oakland, CA), between January 2003 and March 2004. Patient-, anesthesia- and surgery-related factors that were considered to have a possible effect on the prevalence of PONV events were evaluated. RESULTS: A total of 514 patients met the inclusion criteria. Among these patients, 40.08% experienced PONV during the first 24 hours after surgery. The most important predictive factors associated with an increased risk of PONV were female gender, young patients (15 to 25 years old), nonsmoking status, presence of predisposing factors (ie, prior history of motion sickness and/or PONV, vertigo or migraine headaches), use of volatile general anesthetics, maxillary surgery, postoperative pain level (PACU) and the use of postoperative analgesic opioid drugs. We found a directly proportional relationship between the number of risk factors and the prevalence of PONV. CONCLUSION: We found PONV had a high prevalence among patients undergoing orthognathic surgery. Further studies are needed to develop effective protocols for preventing this common and unpleasant problem.  相似文献   
54.
PURPOSE: Titanium plates and monocortical screws are commonly used to stabilize the mandible following sagittal split ramus osteotomies. Despite widespread use of this type of fixation, there is a paucity of large studies evaluating the infection rate and need for hardware removal. MATERIALS AND METHODS: This study is a retrospective cohort evaluation of 1,066 consecutive mandibular sagittal ramus osteotomies in 533 patients, performed between January 2002 and December 2003. All osteotomies were stabilized with 4-hole miniplates and 2.0 mm x 5.0 mm monocortical screws. Study variables included disturbances of wound healing, age, gender, plate and screw position, direction of mandibular movement, adjunctive procedures performed, and the patient's medical history. Data were collected by chart and radiographic review. The above variables were analyzed using Fisher's exact test, Chi-square, Cochran-Armitage Trend Test, and multiple logistic regression. RESULTS: Of 533 patients 26% (138) demonstrated wound healing problems. This occurred in 15% of all 1,066 osteotomy sites. 6.5% of plates required removal in 10% of patients. In no case did disturbance of wound healing or plate removal result in non-union or relapse of the osteotomy. Wound healing problems were fewer when mandibular osteotomies were done in conjunction with maxillary surgery (18.9% versus 29.1%). Disturbances of wound healing were not related to the direction of movement of the mandible and were lower when hardware was placed closer to the inferior border. CONCLUSION: An overall low incidence (6.5%) of hardware infection requiring plate removal was found in this study. Screw proximity to the osteotomy site did not correlate with higher rates of healing problems, but there was a statistically significant trend of fewer disturbances of healing when the hardware was placed closer to the inferior border of the mandible.  相似文献   
55.
56.
The eyes of a 22-month-old girl with the cobalamin C complementation type of combined methylmalonic aciduria and homocystinuria were studied with light and electron microscopy. We observed vacuolization of the iris pigment epithelium, loss of photoreceptors in the central 3.3 mm of the macula, partial loss of the nerve fiber and ganglion cell layers between the fovea and optic disk, and partial optic atrophy. The sclera in the posterior pole was thickened with deposition of mucopolysaccharide. Electron microscopy showed inclusions containing fine granular material in conjunctival fibrocytes; corneal epithelium, keratocytes, and endothelial cells; iris pigment epithelium; ganglion cells; retinal pigment epithelium; and choroid and scleral fibrocytes. Enlarged mitochondria and clear vacuoles distended the corneal endothelial cells. We found evidence of possible lysosomal dysfunction and mucopolysaccharide storage, as well as a clinicopathologic correlation of the macular degeneration in this disease.  相似文献   
57.
Drug-induced lung disease is an increasingly common cause of morbidity and mortality. The diagnosis is based on clinical history and consistent radiologic findings. Lung biopsy is performed in a small percentage of cases. High-resolution CT may demonstrate parenchymal abnormalities in patients with normal radiographs and provides a better depiction of the pattern and distribution of findings. Knowledge of the most common high-resolution CT manifestations and the corresponding histologic patterns is important for early recognition and proper management of drug-induced lung disease.  相似文献   
58.
INTRODUCTION: It is still controversial whether subjects with white-coat hypertension (WCHT) exhibit higher cardiovascular risk compared to normotensive subjects (NT). In subjects with WCHT it is not known whether the abnormal blood pressure (BP) reaction in the office also occurs at other times of day, particularly on arising and immediately after waking, i.e. the times at which the majority of cardiovascular events are reported to occur. OBJECTIVE AND METHODS: To evaluate with 24h ambulatory BP measurement the values of morning BP surge, BP on arising and BP variability in subjects with WCHT in comparison with age-, gender- and weight-matched normotensives (BP) and untreated sustained hypertensives (BP). RESULTS: Groups of BP, WCHT and BP were matched for age, gender and body weight: BP: n=69, age 49 +/- 7 years, 54 % female, BMI 26 +/- 1, casual BP 126/79 +/- 5/4 mmHg, daytime BP 124/80 +/- 6/6 mmHg; WCHT: n=74, age 52 +/- 8 years, 57% female, BMI 26 +/- 2, casual BP 152/95 +/- 7/7 mmHg, daytime BP 126/80 +/- 5/6 mmHg; HT: n=79, age 53 +/- 7 years, 56% female, BMI 27 +/- 2, casual BP 154/97 +/- 9/8 mmHg, daytime BP 143/89 +/- 12/10 mmHg. Of the three groups, subjects with WCHT exhibited BP on arising (121/81 +/- 13/8 mmHg) similar to that of NTs (120/80 +/- 13/9 mmHg, NS), both significantly lower than that of HTs (137/92 +/- 17/10 mmHg, p < 0.01), suggesting the absence of an alerting BP reaction in WCHT at that time. By contrast, subjects with WCHT showed higher values of systolic morning BP surge vs. NTs (25 +/- 10 vs. 22 +/- 11 mmHg, p < 0.05), both lower than that observed in hypertensives (33 +/- 11 mmHg, p < 0.01 vs. NT and WCHT) and greater daytime variability (systolic BP standard variation), i.e. 12 2 vs. 10 +/- 2 mmHg, p < 0.05, both lower than that observed in hypertensives (14 +/- 3 mmHg, p < 0.01 vs. NT and WCHT). CONCLUSIONS: Although subjects with WCHT did not show any alerting blood pressure reaction on arising, morning BP surge and BP variability were greater in these subjects than in control normotensives, although lower than sustained hypertensives. Although this is still speculative, we cannot exclude the possibility that even a slight increase in morning BP surge might in the long term constitute an additional load on the circulation that could increase cardiovascular risk in subjects with WCHT compared to matched normotensives.  相似文献   
59.
60.
BACKGROUND: Sensitization to natural rubber latex (Hevea brasiliensis) is a major cause of occupational asthma and rhinitis affecting frequent latex-glove users. Hev b 6.01, a known major latex allergen, is cleaved naturally into hevein (4.7 kDa) and a C-terminal fragment (14 kDa). Hevein is an abundant protein in latex-glove extracts. As the immune response to allergens is initiated by activation of allergen-specific CD4(+) T cells, identification of dominant T cell epitopes is crucial for the development of specific immunotherapy. OBJECTIVE: To identify dominant T cell epitopes of Hev b 6.01 in latex-allergic glove users. METHODS: Ten latex-allergic frequent glove users and six non-latex-allergic atopic control subjects were selected, based on clinical symptoms and positive latex-specific serum IgE. Serum IgE reactivity to glove extract and recombinant Hev b 6.01 (rHev b 6.01) were analysed by ELISA. Latex-specific short-term oligoclonal T cell lines were generated from peripheral blood of latex-allergic subjects. These lines were tested for proliferative responses to overlapping 20-mer peptides of the Hev b 6.01 molecule. CD4(+) T cell intracellular cytokines, IL-4 and IFN-gamma were assessed following stimulation with immobilized anti-CD3 in the presence of IL-2. RESULTS: All ten of the latex-allergic patients showed serum IgE binding to glove extract while eight of these also showed IgE binding to rHev b 6.01 by ELISA. Western blotting confirmed reactivity with rHev b 6.01 at around 20 kDa. T cell proliferation assays showed that latex-specific T cell lines from all subjects responded to one or more peptides, with greatest frequency of reactivity to peptides Hev b 6.01 p(10-29) and Hev b 6.01 p(19-38) in the hevein domain. An allergic-type cytokine profile with considerable IL-4 in addition to IFN-gamma was evident from intracellular cytokine staining. CONCLUSION: Hevein is an important T cell as well as B cell immunogen and contains dominant T cell reactive sites.  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