全文获取类型
收费全文 | 860999篇 |
免费 | 71516篇 |
国内免费 | 1837篇 |
专业分类
耳鼻咽喉 | 12799篇 |
儿科学 | 24623篇 |
妇产科学 | 25096篇 |
基础医学 | 124197篇 |
口腔科学 | 25484篇 |
临床医学 | 75300篇 |
内科学 | 164524篇 |
皮肤病学 | 16973篇 |
神经病学 | 70068篇 |
特种医学 | 35190篇 |
外国民族医学 | 171篇 |
外科学 | 136143篇 |
综合类 | 24603篇 |
现状与发展 | 2篇 |
一般理论 | 263篇 |
预防医学 | 66863篇 |
眼科学 | 20517篇 |
药学 | 64685篇 |
中国医学 | 1593篇 |
肿瘤学 | 45258篇 |
出版年
2018年 | 7331篇 |
2015年 | 7722篇 |
2014年 | 11105篇 |
2013年 | 16774篇 |
2012年 | 22705篇 |
2011年 | 23821篇 |
2010年 | 13859篇 |
2009年 | 13058篇 |
2008年 | 22561篇 |
2007年 | 24612篇 |
2006年 | 24485篇 |
2005年 | 24132篇 |
2004年 | 23695篇 |
2003年 | 22826篇 |
2002年 | 21921篇 |
2001年 | 35822篇 |
2000年 | 36464篇 |
1999年 | 30895篇 |
1998年 | 9220篇 |
1997年 | 8545篇 |
1996年 | 8475篇 |
1995年 | 8006篇 |
1994年 | 7723篇 |
1992年 | 26658篇 |
1991年 | 26098篇 |
1990年 | 25617篇 |
1989年 | 24677篇 |
1988年 | 23219篇 |
1987年 | 22883篇 |
1986年 | 21740篇 |
1985年 | 21097篇 |
1984年 | 16385篇 |
1983年 | 13996篇 |
1982年 | 8854篇 |
1981年 | 8201篇 |
1980年 | 7671篇 |
1979年 | 16736篇 |
1978年 | 12114篇 |
1977年 | 10181篇 |
1976年 | 9328篇 |
1975年 | 10147篇 |
1974年 | 12641篇 |
1973年 | 12136篇 |
1972年 | 11538篇 |
1971年 | 10685篇 |
1970年 | 10218篇 |
1969年 | 9909篇 |
1968年 | 8900篇 |
1967年 | 8230篇 |
1966年 | 7653篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
C T Gan G P McCann J T Marcus S A van Wolferen J W Twisk A Boonstra P E Postmus A Vonk-Noordegraaf 《The European respiratory journal》2006,28(6):1190-1194
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function. 相似文献
172.
173.
Chan C. H. Y Ng E. H. Y Chan C. L W 《世界核心医学期刊文摘》2006,2(6):15-15
目的:评价东部身体-智力-精神(EBMS)群体干预对进行体外受精(IVF)的中国妇女焦虑缓解的作用。设计:随机对照研究。机构:三级辅助生殖机构。受试者:227例接受第1个IVF周期治疗的妇女。干预:干预组(n=69)接受4次EBMS群体咨询,而对照组(n=115)无任何干预。主要观察指标:状态-特质焦虑问卷。结果:与对照组相比,干预组在干预后状态焦虑平均分显著下降。每组移植同样数目的卵子,但干预组没有明显更高妊娠率的倾向。 相似文献
174.
175.
B Alisjahbana R van Crevel E Sahiratmadja M den Heijer A Maya E Istriana H Danusantoso T H M Ottenhoff R H H Nelwan J W M van der Meer 《The international journal of tuberculosis and lung disease》2006,10(6):696-700
SETTING: Diabetes mellitus is a known risk factor for tuberculosis (TB), but no studies have been reported from South-East Asia, which has a high burden of TB and a rapidly growing prevalence of diabetes. OBJECTIVE: To examine if and to what extent diabetes is associated with an increased risk of TB in an urban setting in Indonesia. DESIGN: Case-control study comparing the prevalence of diabetes mellitus (fasting blood glucose level >126 mg/dl) among newly diagnosed pulmonary TB patients and matched neighbourhood controls. RESULTS: Patients and control subjects had a similar age (median 30 years) and sex distribution (52% male), but malnutrition was more common among TB patients (median body mass index 17.7 vs. 21.5 kg/m2). HIV infection was uncommon (1.5% of patients). Diabetes mellitus was present in 60 of 454 TB patients (13.2%) and 18 of 556 (3.2%) control subjects (OR 4.7; 95%CI 2.7-8.1). Adjustment for possible confounding factors did not reduce the risk estimates. Following anti-tuberculosis treatment, hyperglycaemia reverted in a minority (3.7%) of TB patients. CONCLUSION: Diabetes mellitus is strongly associated with TB in young and non-obese subjects in an urban setting in Indonesia. This may have implications for TB control and patient care in this region. 相似文献
176.
Antony E. Shrimpton Robert L. Schelper Reinhold P. Linke John Hardy Richard Crook Dennis W. Dickson Takashi Ishizawa Richard L. Davis 《Neuropathology》2007,27(3):228-232
Over 100 mutations in the presenilin‐1 gene (PSEN1) have been shown to result in familial early onset Alzheimer disease (EOAD), but only a relatively few give rise to plaques with an appearance like cotton wool (CWP) and/or spastic paraparesis (SP). A family with EOAD, seizures and CWP was investigated by neuropathological study and DNA sequencing of the PSEN1 gene. Aβ was identified in leptomeningeal vessels and in cerebral plaques. A single point mutation, p.L420R (g.1508T > G) that gives rise to a missense mutation in the eighth transmembrane (TM8) domain of PS1 was identified in two affected members of the family. p.L420R (g.1508T > G) is the mutation responsible for EOAD, seizures and CWP without SP in this family. 相似文献
177.
Rachel N. Pauls Jeffrey L. Segal W. Andre Silva Steven D. Kleeman Mickey M. Karram 《International urogynecology journal》2006,17(6):576-580
The purpose of this study was to evaluate sexual function in women referred to a urogynecology practice. All new patients were mailed an optional female sexual function index (FSFI) in conjunction with their history forms; other sexual function information was obtained during the physician interview. Over 6 months, four hundred fifty new patients were enrolled. Of these, 243 (54%) were not sexually active. Reasons listed for sexual inactivity included partner problems/no partner (32%), low desire (14%), prolapse (10%), and pain (10%). There were several differences between sexually active and non-sexually active participants; however, after a multivariate analysis, only age, marital status, and stage/grade 1–2 of prolapse remained significant. One hundred nine sexually active patients completed the FSFI; the majority was sexually active two to four times per month. Female sexual dysfunction was noted in 70 (64%) patients. Lowest scores were noted for the domain of desire, followed by arousal, orgasm, lubrication, satisfaction, and pain. Reduced frequency of intercourse was the only factor significantly associated with dysfunction. Ninety-four percent were not embarrassed by the survey. Overall, sexual inactivity is common in patients presenting for urogynecologic care. Those that are sexually active report low rates of sexual activity and high rates of sexual dysfunction. Most sexually active patients will accept a sexual function questionnaire as part of their routine assessment.This research was presented at the American College of Obstetricians and Gynecologists annual clinical meeting, May 10, 2005, San Francisco, CA, USA. 相似文献
178.
Sami S Zoghbi H Umesha Shetty Masanori Ichise Masahiro Fujita Masao Imaizumi Jeih-San Liow Jay Shah John L Musachio Victor W Pike Robert B Innis 《Journal of nuclear medicine》2006,47(3):520-527
18F-2beta-Carbomethoxy-3beta-(4-chlorophenyl)-8-(2-fluoroethyl)nortropane (18F-FECNT), a PET radioligand for the dopamine transporter (DAT), generates a radiometabolite that enters the rat brain. The aims of this study were to characterize this radiometabolite and to determine whether a similar phenomenon occurs in human and nonhuman primate brains by examining the stability of the apparent distribution volume in DAT-rich (striatum) and DAT-poor (cerebellum) regions of the brain. METHODS: Two rats were infused with 18F-FECNT and sacrificed at 60 min. Extracts of brain and plasma were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometric (LC-MS) techniques. Two human participants and 3 rhesus monkeys were injected with 18F-FECNT and scanned kinetically, with serial arterial blood analysis. RESULTS: At 60 min after the injection of rats, 18F-FECNT accumulated to levels about 7 times higher in the striatum than in the cortex and cerebellum. The radiometabolite was distributed at equal concentrations in all brain regions. The LC-MS techniques identified N-dealkylated FECNT as a major metabolite in the rat brain, and reverse-phase HPLC detected an equivalent amount of radiometabolite eluting with the void volume. The radiometabolite likely was 18F-fluoroacetaldehyde, the product expected from the N-dealkylation of 18F-FECNT, or its oxidation product, 18F-fluoroacetic acid. The distribution volume in the cerebellum increased up to 1.7-fold in humans between 60 and 300 min after injection and 2.0 +/- 0.1-fold (mean +/- SD; n = 3) in nonhuman primates between 60 and 240 min after injection. CONCLUSION: An 18F-fluoroalkyl metabolite of 18F-FECNT originating in the periphery confounded the measurements of DAT in the rat brain with a reference tissue model. Its uniform distribution across brain regions suggests that it has negligible affinity for DAT (i.e., it is an inactive radiometabolite). Consistent with the rodent data, the apparent distribution volume in the cerebellum of both humans and nonhuman primates showed a continual increase at late times after injection, a result that may be attributed to entry of the radiometabolite into the brain. Thus, reference tissue modeling of 18F-FECNT will be prone to more errors than analysis with a measured arterial input function. 相似文献
179.
Abbas Agaimy Peter H. Wünsch 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2006,391(4):322-329
Background Gastrointestinal stromal tumours (GISTs) are thought to arise from the interstitial cells of Cajal (ICCs). ICCs form a network surrounding the myenteric plexus and between-muscle fibres of the muscularis propria of the tubular GI tract. The cell of origin of so-called extra-gastrointestinal stromal tumours (EGISTs) is not known.Aim and methods To study the diversity of gross presentation of GISTs and to critically assess the incidence of EGISTs and their relationship to mural GISTs, a total of 200 neoplasms with typical morphologic and immunohistochemical features of GISTs were reviewed, looking for any degree of association with the muscularis propria of the gut wall.Results There were 130 gastric (65%), 9 duodenal (4.5%), 48 small intestinal (24%), 9 colorectal (4.5%), 1 appendiceal (0.5%) and 3 unclassifiable GISTs (1.5%). Fourteen cases (7%) were initially submitted as EGISTs (four mesenteric, four omental, one pararectal/prostatic, one pelvic/Douglas, one perivesical, one located between root of mesentery and tail of pancreas, one involving the mesentery, omentum and abdominal wall extensively and one located between liver and stomach). After critical re-evaluation of surgical reports and remote clinical history and a careful search for residual muscular tissue from the gut wall in the tumour pseudocapsule (in some cases supported by desmin immunoreactivity), it was possible to reclassify most of these cases (11/14) as either GISTs with extensive extramural growth resulting in loss of contact to the external muscle coat of the gut (8/14) or as metastases from an inoperable GIST (2/14) or from a previously resected deceptively benign tumour (1/14).Conclusion EGISTs are probably rarer than previously reported (1.5% or less in this study). We concluded that most so-called EGISTs represent apparent EGISTs that should have arisen from the outermost muscle coat, but have lost their contact to the point of origin due to extensive extramural growth pattern. From a surgical point of view, it is crucial to document and mark any focal attachment or adhesions to the gut wall noticed during surgery for an apparent EGIST. In contrast to most other neoplasms, GISTs should be defined by virtue of any degree of association with the muscularis propria (no matter how minimal), but not by localisation of the bulk of the tumour. 相似文献
180.
Poor results after surgery for bronchioloalveolar carcinoma. 总被引:2,自引:0,他引:2
R A M Damhuis P R Schütte O C M Varin P M van den Berg R Heinhuis P W Plaisier 《European journal of surgical oncology》2006,32(5):573-576
BACKGROUND: Bronchioloalveolar carcinoma (BAC) is suggested to be less aggressive than other types of lung cancer. To assess the option of treatment modification, actual outcome data were studied and compared with results for other types of lung cancer. METHOD: Retrospective analysis of all consecutive patients who underwent resection for stage I lung cancer in our hospital. For 18 BAC cases, histological specimens were re-evaluated and in three cases diagnosis was revised. RESULTS: In the period 1989 through 2000, 15 patients with BAC and 260 patients with other tumour types underwent surgery in our hospital. Five-year survival rates were 24 and 53%, respectively, (p = 0.01). CONCLUSIONS: Given the poor results after standard surgery, parenchyma-sparing operations do not seem justified in patients with invasive BAC. 相似文献