全文获取类型
收费全文 | 6296篇 |
免费 | 413篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 157篇 |
妇产科学 | 236篇 |
基础医学 | 969篇 |
口腔科学 | 89篇 |
临床医学 | 729篇 |
内科学 | 1253篇 |
皮肤病学 | 110篇 |
神经病学 | 673篇 |
特种医学 | 398篇 |
外科学 | 836篇 |
综合类 | 54篇 |
一般理论 | 1篇 |
预防医学 | 300篇 |
眼科学 | 121篇 |
药学 | 285篇 |
2篇 | |
中国医学 | 12篇 |
肿瘤学 | 396篇 |
出版年
2022年 | 46篇 |
2021年 | 85篇 |
2020年 | 56篇 |
2019年 | 84篇 |
2018年 | 92篇 |
2017年 | 69篇 |
2016年 | 95篇 |
2015年 | 139篇 |
2014年 | 183篇 |
2013年 | 242篇 |
2012年 | 316篇 |
2011年 | 310篇 |
2010年 | 232篇 |
2009年 | 184篇 |
2008年 | 289篇 |
2007年 | 301篇 |
2006年 | 318篇 |
2005年 | 281篇 |
2004年 | 258篇 |
2003年 | 240篇 |
2002年 | 218篇 |
2001年 | 235篇 |
2000年 | 218篇 |
1999年 | 175篇 |
1998年 | 90篇 |
1997年 | 63篇 |
1996年 | 76篇 |
1995年 | 70篇 |
1994年 | 52篇 |
1993年 | 59篇 |
1992年 | 114篇 |
1991年 | 124篇 |
1990年 | 113篇 |
1989年 | 107篇 |
1988年 | 95篇 |
1987年 | 85篇 |
1986年 | 69篇 |
1985年 | 79篇 |
1984年 | 57篇 |
1983年 | 47篇 |
1982年 | 34篇 |
1979年 | 66篇 |
1978年 | 36篇 |
1977年 | 43篇 |
1976年 | 31篇 |
1975年 | 36篇 |
1974年 | 41篇 |
1973年 | 43篇 |
1972年 | 45篇 |
1971年 | 36篇 |
排序方式: 共有6718条查询结果,搜索用时 15 毫秒
71.
Statistic analysis of data from 209 calcium oxalate stone patients and 42 stone-free patients pertinent to the concentration and excretion of uric acid in urine and of uric acid levels in the serum yielded no significant difference between the two groups. Only 17% of the calcium oxalate stone patients suffered from hyperuricuria and hyperuricemia was found only in 15% of these patients. Based on these findings, our in-vitro experiments as to the influence of uric acid on calcium oxalate stone formation yielded the following results: firstly, precipitates in urine form only at uric acid concentrations which in-vivo are rate exceptions humans, and secondly, the precipitates at pH 5.5--6.0 always contain uric acid, and a precipitation of calcium oxalate only is never observed. From the experiments one has to conclude that there exists no "salting-out effect" of uric acid on calcium oxalate in urine but rather that precipitate formation reflects the individual solution- and crystallization characteristics of the precipitating compounds. 相似文献
72.
Stefan Holdenrieder Jutta Stief Albrecht Bergner Fernando Gamarra Anke Mitlewski Dorothea Nagel Rudolph M Huber Petra Stieber 《Tumour biology》2004,25(5-6):321-326
Nucleosomes, which are typical cell death products, are elevated in the serum of cancer patients and are known to rapidly increase during radiotherapy. As both normal and malignant cells are damaged by irradiation, we investigated to which extent both cell types contribute to the release of nucleosomes. We cultured monolayers of normal bronchoepithelial lung cells (BEAS-2B, n = 18) and epithelial lung cancer cells (EPLC, n = 18), exposed them to various radiation doses (0, 10 and 30 Gy) and observed them for 5 days. Culture medium was changed every 24 h. Subsequently, nucleosomes were determined in the supernatant by the Cell Death Detection-ELISA(plus) (Roche Diagnostics). Additionally, the cell number was estimated after harvesting the cells in a second preparation. After 5 days, the cell number of BEAS-2B cultures in the irradiated groups (10 Gy: median 0.03 x 10(6) cells/culture, range 0.02-0.08 x 10(6) cells/culture; 30 Gy: median 0.08 x 10(6) cells/culture, range 0.02-0.14 x 10(6) cells/culture) decreased significantly (10 Gy: p = 0.005; 30 Gy p = 0.005; Wilcoxon test) compared to the non-irradiated control group (median 4.81 x 10(6) cells/culture, range 1.50-9.54 x 10(6) cells/culture). Consistently, nucleosomes remained low in the supernatant of non-irradiated BEAS-2B. However, at 10 Gy, BEAS-2B showed a considerably increasing release of nucleosomes, with a maximum at 72 h (before irradiation: 0.24 x 10(3) arbitrary units, AU, range 0.13-4.09 x 10(3) AU, and after 72 h: 1.94 x 10(3) AU, range 0.11-5.70 x 10(3) AU). At 30 Gy, the release was even stronger, reaching the maximum earlier (at 48 h, 11.09 x 10(3) AU, range 6.89-18.28 x 10(3) AU). In non-irradiated EPLC, nucleosomes constantly increased slightly. At 10 Gy, we observed a considerably higher release of nucleosomes in EPLC, with a maximum at 72 h (before irradiation: 2.79 x 10(3) AU, range 2.42-3.80 x 10(3) AU, and after 72 h: 7.16 x 10(3) AU, range 4.30-16.20 x 10(3) AU), which was more than 3.5 times higher than in BEAS-2B. At 30 Gy, the maximum (6.22 x 10(3) AU, range 5.13-9.71 x 10(3) AU) was observed already after 24 h. These results indicate that normal bronchoepithelial and malignant lung cancer cells contribute to the release of nucleosomes during irradiation in a dose- and time-dependent manner with cancer cells having a stronger impact at low doses. 相似文献
73.
Barbara Seliger Derek Atkins Michaela Bock Ulrike Ritz Soldano Ferrone Christoph Huber Stefan St?rkel 《Clinical cancer research》2003,9(5):1721-1727
The HLA class I antigen-processing machinery (APM) plays a crucial role in the generation of peptides from endogenously synthesized proteins and in their presentation to cytotoxic T lymphocytes. The potential role of defects of APM components in immune escape mechanisms used by malignant cells has prompted us to analyze their expression in renal cell carcinoma (RCC) lesions with special emphasis on TAP because of its critical role in the loading of HLA class I antigens with peptides. Immunohistochemical staining of 51 formalin-fixed RCC lesions and autologous normal renal epithelium detected transporter associated with antigen processing (TAP)1 and tapasin deficiencies in 63 and 80% of the tumor lesions. Impaired low molecular weight protein (LMP)2 and LMP7 expression was found in 73 and 33% of the RCC lesions analyzed, respectively. In contrast to the high frequency of APM component down-regulation, HLA class I heavy chain and beta(2)-microglobulin defects were detected in only 12 and 10% of the lesions, respectively. Concomitant TAP1 and LMP2 deficiencies were found in approximately 57% of RCC lesions, whereas a coordinated down-regulation of all APM components occurred only in 5% of the tumor specimens analyzed. The presence of APM defects was independent of tumor stage and grade but varied significantly among the RCC subtypes. TAP abnormalities do not appear to be attributable to structural alterations because no mutations in TAP1 were detected in TAP1-deficient RCC lesions. These data suggest that TAP defects in RCC lesions are caused by regulatory abnormalities. Therefore, T-cell-based immunotherapy may benefit from the administration of cytokines that up-regulate TAP expression. 相似文献
74.
Huber M Ayoub M Pfannes SD Mittenbühler K Weis K Bessler WG Baier W 《European journal of medical research》2000,5(3):101-109
The bacterial extract OM-89 used for the prevention and treatment of recurrent urinary tract infections constitutes an effective immunostimulant in vitro and in vivo. Here we demonstrate that OM-89 shows mitogenic properties towards murine spleen cell cultures from LPS responder and non-responder mice. In macrophages the extract induces the translocation of NF-kappaB into the cell nucleus and RNI (radical nitrogen intermediates) release, which could be attributed to single fractions of the extract. Our findings on the in vitro immunostimulatory effect of OM-89, as well as its immunogenic and adjuvant properties, are of importance for understanding its therapeutic efficacy as demonstrated in clinical studies. 相似文献
75.
Lang SM Stratakis DF Freudling A Ebelt K Oduncu F Hautmann H Huber RM 《European journal of medical research》2000,5(8):341-346
Molecular screening may increase the likelihood to identify early malignant lesions in non-small cell lung cancer. However the presence of gene mutations in non-malignant bronchial tissue has remained controversial. The present study was carried out to investigate systematically the presence of mutations of the K-ras and p53 gene in bronchial biopsies taken during routine bronchoscopy of normal as well as tumour tissues from a series of 40 patients with histologically verified non-small cell lung cancer (NSCLC). K-ras mutations were analysed with specific detection oligonucleotides, p53 mutations were examined by SSCP analysis. In all biopsies the wildtype of both K-ras and p53 could be detected. The overall frequency of mutations was 14 (35%) with 2 K-ras mutations (5%) and 12 mutations of the p53 gene (30%). In 3 cases (1 ras mutation, 2 p53 mutations) the same mutation could be shown in the tumour biopsy and in the distant normal control. In another case only the normal appearing tissue had a mutation of the p53 gene. All other mutations could be detected in the tumour tissue only. Our data confirm that K-ras mutations and p53 can be detected not only in malignant but also in non-malignant bioptic samples from patients with NSCLC. The use of molecular screening for the early detection of lung cancer may be a promising new approach. 相似文献
76.
L Patel PE Clayton ME Jenney JE Ferguson TJ David 《Archives of disease in childhood》1997,76(6):505-508
Cross sectional studies have reported impaired growth in children with atopic dermatitis. If this growth impairment is irreversible, it would be expected to adversely influence final height attainment. The standing heights and other anthropometric parameters were assessed in 35 adults with onset of atopic dermatitis before 5 years of age and a control group of 35 adults with adult onset contact dermatitis or psoriasis. There was no significant difference in the standing height SD score, mid-parental height SD score, sitting height SD score, subischial leg length SD score, nor body mass index between the atopic dermatitis and control groups. The standing height SD score was not significantly different among: (a) patients with atopic dermatitis affecting less than 50% of their body surface area and those with greater than 50% affected; (b) patients using the four different potency topical corticosteroids; and (c) patients with atopic dermatitis without asthma and those with coexisting asthma. It is concluded that short stature is not a feature of our group of adult patients with onset of atopic dermatitis before 5 years of age, continuing into adulthood, and severe enough to require specialist care. This suggests that if growth impairment occurs in childhood, it is likely to be temporary and reversible. 相似文献
77.
Grunt ThW E. Dittrich M. Offterdinger S. M. Schneider Ch Dittrich H. Huber 《British journal of cancer》1998,78(1):79-87
We investigated the effects of all-trans retinoic acid (ATRA) and fenretinide (4-HPR) on c-erbB-2 expression in SK-BR-3, BT-474 and MCF-7 breast cancer cells and on the growth, differentiation, apoptosis and cisplatin (CDDP) sensitivity of SK-BR-3 cells. It has been reported that oestrogen inhibits c-erbB-2 in oestrogen receptor-positive breast cancer cells. Using ELISA, Western and Northern analysis we have demonstrated that ATRA and 4-HPR exert similar effects down-regulating c-erbB-2 protein and mRNA in c-erbB-2-overexpressing SK-BR-3 and BT-474 and in normally expressing MCF-7 cells. Both retinoids inhibit SK-BR-3 cell growth. ATRA induces cellular enlargement and flattening, suggesting epithelial differentiation. 4-HPR causes nuclear and cytoplasmic condensation, DNA fragmentation and externalization of phosphatidylserine, indicating apoptosis. c-erbB-2 expression/activity has been linked to sensitivity against CDDP. Therefore, combinations of ATRA or 4-HPR with CDDP were tested for their anti-proliferative activity. Retinoid-conditioned cells were either exposed to retinoid and CDDP (schedule I, ''continuous retinoid treatment'') or to CDDP alone (schedule II, ''retinoid pretreatment''). This retinoid-conditioning followed by CDDP +/- retinoid yields stronger growth inhibition compared with unconditioned cells, which were exposed to CDDP +/- retinoid (schedule III, ''no retinoid pretreatment''). The inefficacy of schedule III indicates that retinoid-conditioning is essential for the improvement of the antiproliferative effect. The interactions in schedules I and II are synergistic for ATRA and CDDP, but slightly antagonistic for 4-HPR and CDDR However, 4-HPR + CDDP is more effective in growth inhibition than each drug alone. 相似文献
78.
Evaluation of an instrumented walkway for measurement of the kinematic parameters of gait 总被引:1,自引:0,他引:1
The purpose of this study was to compare kinematic gait parameters measured with an instrumented walkway system (GAITRite(R)) and a video-based system (peak performance motus 3.1(R)). Subjects walked across a GAITRite mat with embedded pressure sensors. Reflective markers were attached to subjects' shoes and video capture was simultaneously performed during each trial. Video data were then digitized manually using peak software. Correlation coefficients for all parameters measured with both systems were high (>/=0.94). Significant differences between systems were found with analysis of variance (ANOVA) for two parameters, step length and stride velocity (P=0.003, 0.0002). The results of this study indicate that the instrumented walkway gave comparable results for temporal parameters but further investigation is needed to evaluate the fidelity of its spatial performance. 相似文献
79.
BACKGROUND: Although nonoperative treatment has been a major advance in the management of liver trauma, emergency surgery is still required for unstable patients. Severe hepatic lesions located in the right lobe, notably juxtahepatic venous injuries, are difficult to access and still carry a high mortality. METHODS: We describe a surgical approach for severe blunt injury to the right liver by a combined midline-transverse incision. This techniques allows simple, easy, and rapid mobilization and compression of the liver to control bleeding. RESULTS: This technique was used in 10 patients with blunt liver trauma, with grade III (n = 2), IV (n = 5), and V (n = 3) injuries. Mean intraoperative blood transfusion required was 21 units. Six patients underwent mandatory anatomic resection, three patients were treated by hepatic suture, and one patient was treated by packing. This patient developed brain death after surgery and was the only mortality. CONCLUSION: This technique is efficient and less cumbersome than shunting approaches. 相似文献
80.
O'Hara DA Duff A Berlin JA Poses RM Lawrence VA Huber EC Noveck H Strom BL Carson JL 《Anesthesiology》2000,92(4):947-957
BACKGROUND: The impact of anesthetic choice on postoperative mortality and morbidity has not been determined with certainty. METHODS: The authors evaluated the effect of type of anesthesia on postoperative mortality and morbidity in a retrospective cohort study of consecutive hip fracture patients, aged 60 yr or older, who underwent surgical repair at 20 US hospitals between 1983 and 1993. The primary outcome was defined as death within 30 days of the operative procedure. The secondary outcomes were postoperative 7-day mortality, postoperative myocardial infarction, postoperative pneumonia, postoperative congestive heart failure, and postoperative change in mental status. Numerous comorbid conditions were controlled for individually and by several comorbidity indices using logistic regression. RESULTS: General anesthesia was used in 6,206 patients (65.8%) and regional anesthesia in 3,219 patients (3,078 spinal anesthesia and 141 epidural anesthesia). The 30-day mortality rate in the general anesthesia group was 4.4%, compared with 5.4% in the regional anesthesia group (unadjusted odds ratio = 0.80; 95% confidence interval = 0.66-0.97). However, the adjusted odds ratio for general anesthesia increased to 1.08 (0.84-1.38). The adjusted odds ratios for general anesthesia versus regional anesthesia for the 7-day mortality was 0.90 (0.59-1.39) and for postoperative morbidity outcomes were as follows: myocardial infarction: adjusted odds ratio = 1.17 (0.80-1.70); congestive heart failure: adjusted odds ratio = 1.04 (0.80-1.36); pneumonia: adjusted odds ratio = 1.21 (0.87-1.68); postoperative change in mental status: adjusted odds ratio = 1.08 (0.95-1.22). CONCLUSIONS: The authors were unable to demonstrate that regional anesthesia was associated with better outcome than was general anesthesia in this large observational study of elderly patients with hip fracture. These results suggest that the type of anesthesia used should depend on factors other than any associated risks of mortality or morbidity. 相似文献