全文获取类型
收费全文 | 22296篇 |
免费 | 1516篇 |
国内免费 | 543篇 |
专业分类
耳鼻咽喉 | 370篇 |
儿科学 | 515篇 |
妇产科学 | 265篇 |
基础医学 | 2348篇 |
口腔科学 | 527篇 |
临床医学 | 2529篇 |
内科学 | 3839篇 |
皮肤病学 | 807篇 |
神经病学 | 1648篇 |
特种医学 | 688篇 |
外国民族医学 | 2篇 |
外科学 | 1158篇 |
综合类 | 2755篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 2172篇 |
眼科学 | 1173篇 |
药学 | 2428篇 |
6篇 | |
中国医学 | 313篇 |
肿瘤学 | 808篇 |
出版年
2024年 | 24篇 |
2023年 | 232篇 |
2022年 | 349篇 |
2021年 | 747篇 |
2020年 | 702篇 |
2019年 | 706篇 |
2018年 | 658篇 |
2017年 | 634篇 |
2016年 | 712篇 |
2015年 | 769篇 |
2014年 | 1309篇 |
2013年 | 1671篇 |
2012年 | 1198篇 |
2011年 | 1330篇 |
2010年 | 1148篇 |
2009年 | 1100篇 |
2008年 | 1164篇 |
2007年 | 1107篇 |
2006年 | 954篇 |
2005年 | 815篇 |
2004年 | 727篇 |
2003年 | 620篇 |
2002年 | 547篇 |
2001年 | 469篇 |
2000年 | 380篇 |
1999年 | 364篇 |
1998年 | 333篇 |
1997年 | 313篇 |
1996年 | 253篇 |
1995年 | 255篇 |
1994年 | 231篇 |
1993年 | 238篇 |
1992年 | 215篇 |
1991年 | 189篇 |
1990年 | 186篇 |
1989年 | 194篇 |
1988年 | 170篇 |
1987年 | 154篇 |
1986年 | 148篇 |
1985年 | 170篇 |
1984年 | 174篇 |
1983年 | 108篇 |
1982年 | 97篇 |
1981年 | 85篇 |
1980年 | 82篇 |
1979年 | 77篇 |
1978年 | 59篇 |
1977年 | 51篇 |
1976年 | 38篇 |
1975年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
41.
2003-2005年新生儿感染常见致病菌及耐药性的变迁 总被引:10,自引:2,他引:8
目的了解本地区新生儿2003至2005年感染常见致病菌的种类及耐药的现状,以指导临床合理应用抗生素。方法收集我院新生儿科2003年1月至2005年12月收治的613份体液培养阳性(痰液、血液、分泌物、胃液等标本)的患儿资料,对常见检出菌及其耐药性的变迁情况进行分析。结果共检出40种613株病原菌,以革兰阴性杆菌为主约占57.6%,而肺炎克雷伯菌和大肠埃希菌分别位于前二位,其产ESBLs菌株检出率分别为78.1%和82.6%。药敏结果显示,常见致病菌对青霉素、第一、二代头胞类抗生素、红霉素类耐药性显著增加,但对第三代头胞类抗生素如头孢曲松、头孢噻肟(凯福隆)、头孢他啶(复达欣)及B内酰胺酶抑制剂复方制剂、碳青霉烯类、万古霉素等较敏感。产ESBLs菌仅对亚胺培南及B内酰胺酶抑制剂复方制剂敏感。结论革兰阴性杆菌特别是肺炎克雷伯菌和大肠埃希菌是新生儿感染主要病原菌,产ESBLs菌比例增加应引起高度重视。碳青霉烯类、哌拉西林/三唑巴坦和头孢哌酮/舒巴坦,可作为新生儿严重医院感染经验用药,应尽量根据药敏试验调整抗生素。 相似文献
42.
Myriam Costa Stphanie Potvin Imane Hammana Arnaud Malet Yves Berthiaume Alphonse Jeanneret Annick Lavoie Rene Lvesque Joëlle Perrier Danielle Poisson Antony D. Karelis Jean-Louis Chiasson Rmi Rabasa-Lhoret 《Journal of cystic fibrosis》2007,6(6):376-383
BACKGROUND: Abnormal glucose tolerance is a frequent co-morbidity in cystic fibrosis patients (CF), and is associated with a worse prognosis. The objectives are to investigate (a) the relative contribution of insulinopenia and insulin resistance (IR) for glucose tolerance and (b) the association between various glucose parameters and CF clinical status. METHODS: Oral glucose tolerance tests were performed in 114 consecutive CF patients not known to be diabetic as well as 14 controls similar for age and BMI. RESULTS: Abnormal glucose tolerance was found in 40% of patients with CF: 28% had impaired glucose tolerance (IGT) and 12% had new cystic fibrosis related diabetes (CFRD). Compared to control subjects, all CF patients were characterized by an increased glucose excursion (AUC). While reduced early insulin release characterised CF, IGT and CFRD patients also present IR thus both mechanisms significantly contribute to glucose tolerance abnormalities. Increased glucose AUC and reduced early insulin release but not glucose tolerance categories were associated with a reduced pulmonary function (FEV(1)). CONCLUSION: In CF, early insulin secretion defect but also IR contribute to glucose intolerance. Early in the course of the disease, increased glucose AUC and reduced early insulin secretion are more closely associated with a worse clinical status than conventional glucose tolerance categories. 相似文献
43.
COPD机械通气病人下呼吸道感染致病菌分布特点 总被引:1,自引:0,他引:1
①目的 探讨慢性阻塞性肺病(COPD)病人机械通气后下呼吸道感染致病菌的特点。②方法 取32例COPD并发呼吸衰竭行机械通气病人下呼吸道分泌物做痰细菌学培养,同时做药物敏感试验。③结果 32例病人共分离出菌株76株,阳性率71.7%,其中混合感染10例次。其中革兰阴性杆菌(GNB)58株,占76.3%;阳性球菌10株,占13.2%;真菌8株,占10.5%。常见致病菌以铜绿假单胞菌、鲍曼不动杆菌和肺炎杆菌为主,GNB中铜绿假单胞菌和不动杆菌的耐药率高。④结论 COPD应用机械通气病人下呼吸道感染以革兰阴性杆菌为主,耐药性高。 相似文献
44.
45.
A rapid nonsterile short-term assay has been investigated in which percent inhibition of incorporation of the DNA precursor (3H)-thymidine is measured following exposure of tumor cells to the test drugs. To evaluate the usefulness of the short-term assay in providing a rapid reliable assessment of chemotherapeutic response, the short-term assay was compared with the soft agar clonogenic assay. Sensitivity to five anticancer drugs was compared using three human tumor cell lines (epidermoid carcinoma of the oral cavity, pancreatic carcinoma, and bladder carcinoma). The short-term assay produced results that were similar to results of the clonogenic assay in two of the three tumors tested, for three drugs (cis-platin, doxorubicin, and BCNU), but did not detect responses to two antimetabolites (5-FU and MTX) in any tumor. Further studies of this short-term assay should focus on alkylating agents and other nonantimetabolites. 相似文献
46.
茶色素对冠心病及高血压病病人血小板功能的影响 总被引:1,自引:0,他引:1
目的:探索茶色素对冠心病、高血压病病人血小板功能的影响。方法:冠心病病人36例(男性21例,女性15例;年龄64±s4a);高血压病病人30例(男性18例,女性12例;年龄58±8a)。采用茶色素250mg,po,tid,30d为一个疗程。结果:治疗后TXB2下降,6-keto-PGP1α上升,TXB2/6-keto-PGF1α比值下降(P<0.01或P<0.05),GMP-140下降(P<0.05),PagT,PadT下降(P<0.05)。结论:茶色素具有降低血小板表面活性作用,抑制血小板聚集和粘附,抗血栓形成,改善微循环,对冠心病和高血压病病人起到积极的防治作用。 相似文献
47.
绿茶对小鼠Lewis肺癌生长的抑制及免疫调节 总被引:3,自引:0,他引:3
为了研究茶叶防癌作用,以接种Lewis肺癌细胞的C57/BL6J小鼠为实验模型,研究绿茶对带瘤小鼠肿瘤生长的抑制及免疫调节作用。结果表明,接种Lewis肺癌细胞后,C57/BL6J小鼠胸腺重量及其指数减轻,T淋巴细胞CD4亚群阳性百分数及CD+4/CD+8比值下降,外周血白细胞本底化学发光降低,受酵母多糖刺激产生的化学发光增高以及脾IgM抗体生成细胞数减少。绿茶对小鼠体内Lewis肺癌的生长有明显抑制作用,并对上述各项指标的不良改变有不同程度的保护效果 相似文献
48.
IgA antiendomysium antibodies in human umbilical cord sections as a screening test in relatives of patients with celiac disease 总被引:1,自引:0,他引:1
M. Bagnasco P. Montagna A. De Alessandri E. Castellano G. P. Pesce R. Gatti 《Allergy》1997,52(10):1017-1021
We performed the serum IgA antiendomysium antibody (EmA) assay by indirect immunofluorescence on human umbilical cord sections in 86 subjects with celiac disease, in 187 first-degree relatives of such patients, and in a control group of 68 unrelated subjects, to investigate the suitability of the method in the screening of populations at risk of gluten sensitivity. Conventional EmA assay using monkey esophagus sections was performed in parallel experiments. The results obtained showed a perfpect correlation between the two methods. All the celiac patients and none of the controls were positive for EmA. EmA positivity was also observed in 11 apparently healthy relatives: intestinal biopsy performed in five of them invariably showed villous atrophy and increase of mucosal lymphocytes. Taking into account the low cost of EmA assay on human umbilical cord, especially when compared to monkey esophagus sections, the method is probably suitable and effective in identifying latent, asymptomatic gluten sensitivity in at-risk populations. 相似文献
49.
Guthrie and Buchwald (1991) proposed an ad hoc procedure for assessing the statistical significance of waveform difference potentials that may arise in a variety of psychophysiology research contexts. In our paper, an alternative method is presented and demonstrated that has fewer underlying assumptions than does the Guthrie-Buchwald test and may, therefore, produce better results in some situations. In particular, the test proposed here (a) is distribution free, (b) requires no assumption of an underlying correlation structure (e.g., first-order autoregressive), (c) requires no estimate of the population autocorrelation coefficient, (d) is exact, (e) produces p values for any number of subjects and time points, and (f) is highly intuitive as well as theoretically justifiable. This procedure may be used to carry out multiple comparisons with exact specification or experimentwise error, however, this test is based on permutation principles and may require large amounts of computer time for its implementation. 相似文献
50.
Diagnosis and treatment of thoracic outlet syndrome 总被引:2,自引:0,他引:2
Masataka Abe Tadashi Shimamura Jun Nishida Katsuaki Ichinohe 《Journal of orthopaedic science》1997,2(2):119-127
Patients who develop symptoms of thoracic outlet syndrome (TOS) have a predisposing anatomic abnormality. In most patients
with TOS, the symptoms are caused by entrapment of the brachial plexus and they do not arise from compression of the subclavian
artery, as was previously thought. The tests advocated for diagnosing this common syndrome (i.e., evaluating the positional
compression of the artery when the arms are raised, the neck is turned, or the shoulders are braced) cannot accurately diagnose
this syndrome. There are two reasons for this. The symptoms of TOS are not related to the compression of the artery in the
outlet in 98% of patients, and 75% of normal individuals without symptoms show diminished radial pulse on various provocation
tests. We employed four timed provocation tests (minute tests) to diagnose TOS: the timed Morley test, timed Wright test,
timed Eden test, and elevated arm stress exercise, all of which are very sensitive. In normal individuals without symptoms,
20% experience transitional symptoms such as slight pain and tiredness, on these tests indicating a subclinical state. TOS
is treated by keeping the thoracic outlet wide, this being done either conservatively or surgically. In 1993 and 1994, we
conservatively treated 418 of 422 patients with TOS by means of active exercise, a brace, and by block therapy. These measures
did not reduce the symptoms in 23 of these patients, so surgical treatment was indicated. In the remaining 4 of the 422 patients,
conservative treatment was not indicated and surgery was performed directly. All the patients showed significant clinical
improvement of varying degree.
Presented at the 69th Annual Meeting of the Japanese Orthopaedic Association, Tokyo, April 12, 1996 相似文献