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   1134篇
  免费   59篇
  国内免费   11篇
耳鼻咽喉   6篇
儿科学   56篇
妇产科学   18篇
基础医学   109篇
口腔科学   36篇
临床医学   75篇
内科学   244篇
皮肤病学   16篇
神经病学   113篇
特种医学   223篇
外科学   70篇
综合类   15篇
一般理论   2篇
预防医学   41篇
眼科学   5篇
药学   84篇
中国医学   8篇
肿瘤学   83篇
  2023年   5篇
  2022年   14篇
  2021年   21篇
  2020年   15篇
  2019年   22篇
  2018年   28篇
  2017年   17篇
  2016年   17篇
  2015年   33篇
  2014年   49篇
  2013年   38篇
  2012年   58篇
  2011年   61篇
  2010年   48篇
  2009年   56篇
  2008年   46篇
  2007年   36篇
  2006年   51篇
  2005年   44篇
  2004年   42篇
  2003年   37篇
  2002年   33篇
  2001年   6篇
  2000年   11篇
  1999年   15篇
  1998年   34篇
  1997年   41篇
  1996年   49篇
  1995年   34篇
  1994年   28篇
  1993年   39篇
  1992年   5篇
  1991年   4篇
  1990年   12篇
  1989年   10篇
  1988年   12篇
  1987年   21篇
  1986年   22篇
  1985年   12篇
  1984年   9篇
  1983年   5篇
  1982年   22篇
  1981年   7篇
  1980年   6篇
  1977年   10篇
  1976年   7篇
  1975年   7篇
  1973年   1篇
  1971年   1篇
  1904年   1篇
排序方式: 共有1204条查询结果,搜索用时 31 毫秒
51.
Background An increased nutnber of eosinophils in the bronchial mucosa has been demonstrated both in asthma and in exacerbations of chronic bronchitis. Oiyective To investigate whether the airway eosinophilia present in asthma and in chronic bronchitis during exacerbations is associated with interleukin (IL)-5 protein expression in the bronchial mucosa. Methods We obtained bronchial biopsies in 18 subjects with asthma (four intrinsic, seven extrinsic and seven occupational) and in II subjects with chronic bronchitis examined during an exacerbation. The findings were compared wilh those of bronchial biopsies from 10 subjects with chronic bronchitis examined under baseline conditions and from seven normal subjects, taken as controls. By immunohistochemistry, we assessed the expression of IL-5 protein and the number of eosinophils (EG2), mast cells ftryptase), and T-lymphocytes (CD3) in the submucosa. Results As compared with controls, the number of eosinophils was increased to a similar degree in both asthma (P < 0.001) and in exacerbations of ehronic bronchitis (P < 0.001). whereas the number of I L-5 immunopositive cells was increased significantly only in asthma (P < 0.01). No diflerences were observed in the number of tnast cells and T-lymphocytes between the four groups of subjects examined. Conciusions This study shows that the degree of airway eosinophilia is similar in asthma and in exacerbations of ehronic bronchitis, but only in asthma is it associated with an increased expression of I L-5 protein in the bronchial tnucosa.  相似文献   
52.
We report on a patient with a recognizable phenotype of intellectual disability, multiple congenital anomalies, musculoskeletal anomalies and craniofacial dysmorphisms, carrying a de novo 0.4 Mb duplication of chromosome region 16p13.3 detected by SNP-array analysis. In addition, myopia, microcephaly and growth retardation were observed. The causal 16p13.3 duplication is one of the smallest reported so far, and includes the CREB binding protein gene (CREBBP, MIM 600140), whose haploinsufficiency is responsible for the Rubinstein–Taybi syndrome, and the adenylate cyclase 9 gene (ADCY9, MIM 603302). By comparing the clinical manifestations of our patient with those of patients carrying similar rearrangements, we confirmed that 16p13.3 microduplications of the Rubinstein–Taybi region result in a recognizable clinical condition that likely represents a single gene disorder. In addition, our case allowed us to define with more precision the smallest region of overlap (SRO) in all patients reported so far, encompassing only the CREBBP gene, and is useful to confirm and further define the phenotypic characteristics due to duplication of the CREBBP gene, being the first case of interstitial duplication with microcephaly and growth defects reported to date.  相似文献   
53.
Heritable somatic methylation and inactivation of MSH2 in families with Lynch syndrome due to deletion of the 3' exons of TACSTD1
Ligtenberg et al. (2009)
Nature Genetics 41: 112–117  相似文献   
54.
2002年5月1日颁布实施的《中华人民共和国职业病防治法》是规范职业卫生技术服务行为的法律依据。这是职业卫生技术服务工作走上规范化、标准化、法制化的根本保障,是职业卫生技术服务机构参与市场竞争、提高服务质量、促进自身发展的必由之路,也是企业自主选择职业卫生技术服务机构、提高职业危害防治水平、促进经济发展的关键所在。4年多来,我市各级各类职业卫生技术服务机构的发展极不平衡,仪器设备配备水平、人员能力素质与我省同类地区相比也有较大差距。为了解我市职业卫生技术服务机构现状,我们进行了此项调查。  相似文献   
55.
We investigated if orally administered bifidobacteria and/or lactobacilli could be cultured from faeces of infants after antibiotic treatment, when these bacterial species are usually absent. Lyophilized Bifidobacterium longum, strain BB-536, B. breve, strain BB-576, or Lactobacillus acidophilus, strain LAC-343, were used. Doses of 3 x 10(9) cells of one strain, or a mixture of all three strains 3 x 10(9) cells each were fed three times daily at mealtimes to 11 infants aged 0-8 weeks. Treatment was started the first day after antibiotic treatment and was continued for 5 days. The bacterial species were isolated in 9 of 11, 7 of 10 and 2 of 9 specimens obtained on the last day of bifidobacteria or lactobacilli administration, 5 and 15 days thereafter, respectively. No side effects were noted.  相似文献   
56.
Selective ligands for either sigma1 (sigma1) or sigma2 binding sites are potentially useful for gaining a better understanding of the physiological functions of these proteins. Moreover, potent and selective homochiral sigma1 and sigma2 binding site ligands represent leads to potential radioligands for tumour imaging with positron emission tomography (PET). On the basis of their structural similarity to previous leads, new (+)- and (-)-cis-2-[(1-adamantylamino)-methyl]-1-phenylcyclopropane derivatives were synthesised and their binding affinities for sigma1 and sigma2 binding sites were determined. Each enantiomer showed high affinity for both sigma1 and sigma2 binding sites, but only (-)-cis-methyl-2-[[1-adamantyl(methyl)amino]methyl]-1-phenylcyclopropane-carboxylate, (-)-4, showed appreciable selectivity for binding to sigma1 versus sigma2 sites. The enantiomers of cis-(2-[[1-adamantyl(methyl)amino]methyl]-1-phenylcyclopropyl)methanol, 6, expressed the highest affinity for sigma1 and sigma2 binding sites. Ligands (-)-4, (+)-6 and (-)-6 might be rapidly labelled in their N-methyl groups by methylation of the N-desmethyl analogues with [11C]iodomethane to provide prospective radioligands for PET. The N-desmethyl analogues, which are also high affinity ligands, were prepared and shown to undergo satisfactory methylation with iodomethane.  相似文献   
57.
The iminoquinone is an important moiety of a large number of antineoplastic drugs and plays a significant role in the nucleus of actinomycins, powerful, highly toxic, natural antibiotics that target DNA as intercalating agents. A series of polycyclic iminoquinonic compounds, 2-amino-3H-phenoxazin-3-one (1), 2-amino-1,9-diacetyl-3H-phenoxazin-3-one (2), 2-acetylamino-3H-phenoxazin-3-one (3), 3H-phenoxazin-3-one (4), 5H-pyrido[3,2-a]phenoxazin-5-one (5), and 5H-pyrido[3,2-a]phenothiazin-5-one (6), strictly related to the actinomycin chromophore, were synthesized for developing new anticancer intercalating drugs. The antiproliferative activity of these compounds, evaluated against representative human liquid and solid neoplastic cell lines, showed that 5 and its isoster 6 were the most active compounds inhibiting cell proliferation in a submicromolar range. Compound 5 was also evaluated against KB subclones (KBMDR, KB7D, and KBV20C), which overexpress the MDR1/P-glycoprotein drug efflux pump responsible for drug resistance. All the above KB subclones did not show altered sensitivity to the antiproliferative activity of 5. UV-vis and (1)H NMR spectroscopy experiments support the phenoxazinone 5/DNA binding. Molecular mechanics methods were used to build a three-dimensional model of the 5/[d(GAAGCTTC)]2 complex. Electrostatic interactions between the hydrogen of the positively charged pyridine nitrogen of 5 and the negatively charged oxygen atoms (O4' and O5') of the cytosine C5 residue together with stacking forces contribute to the high antiproliferative activity. The metal(II)-assisted synthesis procedure of 5 is described, and the formation mechanism is proposed.  相似文献   
58.
59.
We present a patient with surgical stage I endometrial cancer who experienced laparotomy wound recurrence 4 years after primary treatment. She was treated successfully by complete surgical resection of recurrent tumors and chemotherapy. A 62-year-old white female with laparotomy wound recurrence of endometrial carcinoma with small-bowel involvement and concomitant subcutaneous metastasis in the abdominal wall underwent complete surgical resection of metastatic tumors followed by six cycles of chemotherapy consisting of paclitaxel (175 mg/m2) and carboplatin (area under the curve 5). Since 24 months after resection of recurrence, she has no evidence of disease recurrence. Endometrial carcinoma with laparotomy wound recurrences, especially those with concomitant metastases, can be successfully treated by complete surgical resection followed by chemotherapy consisting of paclitaxel and carboplatin.  相似文献   
60.
Background. Immediate breast reconstruction (IBR) by means of skin expander is currently one of the most widely used methods of breast reconstruction in mastectomized patients. However, given that many breast cancer patients usually receive adjuvant chemotherapy, the adoption of IBR raises new questions concerning possible cumulative toxicity. The present study reports our experience in the use of concurrent adjuvant chemotherapy and immediate breast reconstruction with skin expander after mastectomy for breast cancer and the acute cumulative toxicity of the treatments. Methods. We evaluated a consecutive series of 52 breast cancer patients who have received IBR by skin expander after radical mastectomy and adjuvant chemotherapy concurrently during skin expansion between 1995 and 1998 (IBR/CT group). We identified two series of control patients treated during the same period: 51 consecutive patients undergoing radical mastectomy and IBR without adjuvant chemotherapy (IBR group) and 63 consecutive patients undergoing radical mastectomy and adjuvant chemotherapy without IBR (CT group). For each patient, we evaluated the incidence of surgical complications and chemotherapy's side effects and dose intensity. Results. The interval between surgery and the start of expander inflation was similar in IBR/CT (range 0–19, median 5 days) and IBR groups (range 0–40, median 5 days) and the timing of inflation was not influenced by chemotherapy. The overall incidence of surgical complications in patients undergoing IBR was low: seroma in eight cases, infection in one, skin necrosis in one, expander rupture in two and erythema in three. There were no statistically significant differences in the distribution of complications between the IBR/CT and IBR groups. The dose intensity of chemotherapy was similar between IBR/CT and CT groups, with a median dose intensity of 96% and 95% of the projected dose, respectively. The only statistically significant difference in terms of chemotherapy side effects (p=0.03) was that stomatitis was more frequent and intense in the CT than in the IBR/CT group. Conclusions. Concurrent treatment with IBR and adjuvant chemotherapy appears feasible and safe, it does not increase acute surgical complications or chemotherapy side effects, and does not require any changes in dose intensity or the timing of inflation.  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