全文获取类型
收费全文 | 8118篇 |
免费 | 601篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 236篇 |
妇产科学 | 202篇 |
基础医学 | 1213篇 |
口腔科学 | 75篇 |
临床医学 | 1248篇 |
内科学 | 1546篇 |
皮肤病学 | 113篇 |
神经病学 | 908篇 |
特种医学 | 263篇 |
外科学 | 681篇 |
综合类 | 76篇 |
一般理论 | 8篇 |
预防医学 | 972篇 |
眼科学 | 117篇 |
药学 | 480篇 |
中国医学 | 15篇 |
肿瘤学 | 515篇 |
出版年
2023年 | 64篇 |
2022年 | 60篇 |
2021年 | 221篇 |
2020年 | 126篇 |
2019年 | 215篇 |
2018年 | 241篇 |
2017年 | 184篇 |
2016年 | 200篇 |
2015年 | 232篇 |
2014年 | 271篇 |
2013年 | 374篇 |
2012年 | 592篇 |
2011年 | 546篇 |
2010年 | 309篇 |
2009年 | 281篇 |
2008年 | 471篇 |
2007年 | 520篇 |
2006年 | 428篇 |
2005年 | 470篇 |
2004年 | 452篇 |
2003年 | 449篇 |
2002年 | 382篇 |
2001年 | 102篇 |
2000年 | 90篇 |
1999年 | 101篇 |
1998年 | 83篇 |
1997年 | 65篇 |
1996年 | 60篇 |
1995年 | 73篇 |
1994年 | 39篇 |
1993年 | 55篇 |
1992年 | 52篇 |
1991年 | 50篇 |
1990年 | 57篇 |
1989年 | 38篇 |
1988年 | 44篇 |
1987年 | 41篇 |
1986年 | 46篇 |
1985年 | 47篇 |
1984年 | 48篇 |
1983年 | 40篇 |
1982年 | 39篇 |
1981年 | 26篇 |
1980年 | 30篇 |
1978年 | 21篇 |
1977年 | 19篇 |
1976年 | 32篇 |
1974年 | 25篇 |
1973年 | 22篇 |
1971年 | 23篇 |
排序方式: 共有8741条查询结果,搜索用时 31 毫秒
101.
William M. Splinter Michael R. N. Baxter H. Marion Gould Leslie E. Hall Helen B. MacNeill David J. Roberts Lydia Komocar 《Journal canadien d'anesthésie》1995,42(4):277-280
Vomiting is a common, unpleasant aftermath of tonsillectomy in children. Intraoperative intravenous ondansetron (OND) reduces vomiting after this operation. Our doubleblind, placebocontrolled, randomized investigation studied the effect of the oral form of OND on vomiting after outpatient tonsillectomy in children. We studied 233 healthy children age 2–14 yr undergoing elective tonsillectomy. Subjects were given placebo (PLAC) or OND 0.1 mg · kg?1 rounded off to the nearest 2 mg one hr before surgery. Anaesthesia was induced with either propofol or halothane/N2O. Vecuronium 0.1 mg · kg?1 was administered at the discretion of the anaesthetist. Anaesthesia was maintained with halothane/N2O, 50 μg · kg?1 midazolam iv and 1–1.5 mg · kg?1 codeine im. At the end of surgery, residual neuromuscular blockade was reversed with neostigmine and atropine. All episodes of inhospital emesis were recorded by nursing staff. Rescue antiemetics in the hospital were 1 mg · kg?1 dimenhydrinate ivfor vomiting × 2 and 50 μg · kg?1 droperidol iv for vomiting × 4. Parents kept a diary of emesis after discharge. Postoperative pain was treated with morphine, codeine and/or acetaminophen. The two groups were similar with respect to demographic data, induction technique and anaesthesia time. Oral OND (n = 109) reduced postoperative emesis from 54% to 39%, P < 0.05. This effect was most dramatic inhospital, where 10% of the OND-patients and 30% of the PLAC-group vomited, P < 0.05. The OND-subjects required fewer rescue antiemetics, 7% vs 17%, P < 0.05. In conclusion, oral ondansetron decreased the incidence of vomiting after outpatient tonsillectomy in children. 相似文献
102.
Eng SB Werker DH King AS Marion SA Bell A Issac-Renton JL Irwin GS Bowie WR 《Emerging infectious diseases》1999,5(6):815-819
We used computer-generated dot maps to examine the spatial distribution of 94 Toxoplasma gondii infections associated with an outbreak in British Columbia, Canada. The incidence among patients served by one water distribution system was 3.52 times that of patients served by other sources. Acute T. gondii infection among 3, 812 pregnant women was associated with the incriminated distribution system. 相似文献
103.
104.
One-year study of spatial memory performance, brain morphology, and cholinergic markers after moderate controlled cortical impact in rats 总被引:1,自引:0,他引:1
Dixon CE Kochanek PM Yan HQ Schiding JK Griffith RG Baum E Marion DW DeKosky ST 《Journal of neurotrauma》1999,16(2):109-122
Persistent cognitive deficits are one of the most important sequelae of head injury in humans. In an effort to model some of the structural and neuropharmacological changes that occur in chronic postinjury brains, we examined the longitudinal effects of moderate vertical controlled cortical impact (CCI) on place learning and memory using the Morris water maze (MWM) test, morphology, and vesicular acetylcholine (ACh) transporter (VAChT) and muscarinic receptor subtype 2 (M2) immunohistochemistry. Vertical CCI (left parietal cortex, 4 m/sec, 2.5 mm; n = 10) or craniotomy (sham) was produced in male Sprague-Dawley rats (n = 10). Place learning was tested at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months postinjury with the escape platform in a different maze quadrant for each time point. At each interval, rats received 5 days of water maze acquisition (latency to find hidden platform), a probe trial to measure place memory, and 2 days of visible platform trials to control for nonspecific deficits. At 3 weeks, half the animals were sacrificed for histology. At these injury parameters, CCI produced no significant differences in place learning between injured and sham rats at 2 weeks, 4 weeks, or 6 months after injury. However, at 3 and 12 months, the injured rats took significantly longer to find the hidden platform than the sham rats. Probe trial performance differed only at 12 months postinjury between injured (25.73+/-2.1%, standard error of the mean) and sham rats (44.09+/-7.0%, p < 0.05). The maze deficits at 1 year were not due to a worsening of performance, but may have resulted from a reduced ability of injured rats to benefit from previous water maze experience. Hemispheric loss of 30.4+/-5.5 mm3 was seen at 3 weeks after injury (versus respective sham). However, hemispheric loss almost doubled by 1 year after injury (51.5+/-8.5 mm3, p < 0.05 versus all other groups). Progressive tissue loss was also reflected by a three- to fourfold increase in ipsilateral ventricular volume between 3 weeks and 1 year after injury. At 1 year after injury, immunostaining for VAChT was dramatically increased in all sectors of the hippocampus and cortex after injury. Muscarinic receptor subtype 2 (M2) immunoreactivity was dramatically decreased in the ipsilateral hippocampus. This suggests a compensatory response of cholinergic neurons to increase the efficiency of ACh neurotransmission. Moderate CCI in rats produces subtle MWM performance deficits accompanied by persistent alteration in M2 and VAChT immunohistochemistry and progressive tissue atrophy. The inability of injured rats to benefit from repeated exposures to the MWM may represent a deficit in procedural memory that is independent of changes in hippocampal cholinergic systems. 相似文献
105.
Franke P Leboyer M Hardt J Sohne E Weiffenbach O Biancalana V Cornillet-Lefebre P Delobel B Froster U Schwab SG Poustka F Hautzinger M Maier W 《Psychiatry research》1999,87(2-3):223-231
The present French-German investigation of fragile-X syndrome (fra-X) was undertaken to disentangle genetic from environmental effects on cognitive performance as assessed with the following measures: Wechsler Adult Intelligence Scale-Revised (WAIS-R), Wisconsin Card Sorting Test, Trail-Making Test, Tower of Hanai, Verbal Fluency Test, Stroop Test, short-term and consolidation memory, and the d2 task. Groups with different genotypes (n = 11 mothers with a full mutation in the FMR-1 gene of fra-X children; n = 65 mothers with a premutation in the FMR-1 gene of fra-X children; n = 18 siblings of these mothers with normal CGG repeats) and with different psychosocial stressors from fra-X families (n = 14 siblings with a premutation but without affected children of their own) were examined. A group of mothers of non-fra-X autistic children (n = 39) formed an external control group. Previous findings were replicated concerning cognitive performance of FMR-1 full-mutation carrier mothers, who were characterized by lower overall IQ and poorer performance than the group of mothers with the FMR-1 premutation in verbal and performance subtests of the WAIS-R, tests of executive-frontal lobe functioning, and tests of sustained attention. Carriers of the FMR-1 premutation, whether they were mothers of affected children or not,performed in a similar way on all neuropsychological tasks to the intrafamilial control group without CGG amplification. On the basis of these results, it is concluded that there is no neuropsychological evidence of reduced cognitive performance of FMR-1 premutation carriers compared with performance of two control groups with normal CGG repeats. Furthermore, the psychosocial burden of raising fra-X children does not exert an environmental effect on neuropsychological test performance. 相似文献
106.
Tumor tissue levels of tissue inhibitor of metalloproteinase-1 as a prognostic marker in primary breast cancer. 总被引:8,自引:0,他引:8
Anne-Sofie Schrohl Mads N Holten-Andersen Harry A Peters Maxine P Look Marion E Meijer-van Gelder Jan G M Klijn Nils Brünner John A Foekens 《Clinical cancer research》2004,10(7):2289-2298
PURPOSE: In the present study, we investigated the association between tumor tissue levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and prognosis in patients with primary breast cancer and analyzed whether TIMP-1 may be useful as a prognostic marker in combination with urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1). EXPERIMENTAL DESIGN: In cytosolic extracts of 2984 primary breast tumors, total levels of TIMP-1 were determined using an established, validated ELISA. Levels of uPA and PAI-1 have previously been determined in the extracts. RESULTS: Univariate survival analysis showed a significant relationship between higher levels of TIMP-1 (continuous log-transformed variable) and poor prognosis [recurrence-free survival (RFS), overall survival (OS); P < 0.001]. Performing isotonic regression analysis, we identified a cut point to classify tumors as TIMP-1-low or TIMP-1-high. Using this cut point, high levels of TIMP-1 were significantly associated with shorter survival in univariate analysis, both in the total patient group (RFS, OS; P < 0.001), in the node-negative subgroup (RFS, hazard ratio = 1.28, P = 0.006), and in the node-positive subgroup (RFS, hazard ratio = 1.43, P < 0.001). In multivariate analysis, including uPA and PAI-1, TIMP-1 was significantly associated with shorter RFS, both when included as a continuous log-transformed (P = 0.03) and as a dichotomized variable (P = 0.002). CONCLUSIONS: This study validates previous findings that tumor tissue levels of TIMP-1 are associated with prognosis in patients with primary breast cancer. It confirms that TIMP-1 may be useful as a prognostic marker in combination with uPA/PAI-1 and adds substantial positive information on the use of TIMP-1 as a prognostic marker in breast cancer. 相似文献
107.
Marion P R Van Gellekom Marinus A Moerland Harm K Wijrdeman Jan J Battermann 《Radiotherapy and oncology》2004,73(1):49-56
BACKGROUND AND PURPOSE: To compare the quality of manually inserted RAPID Strand implants with automatically inserted selectSeed implants using volumetric and dosimetric parameters. PATIENTS AND METHODS: Patients with T1 to T2 prostate carcinoma were treated with brachytherapy. The (125)I seeds were implanted in the prostate in three different ways: manual insertion of RAPID Strands (R); insertion of selectSeeds using the seedSelectron (S); a combination of both techniques: manual insertion of RAPID Strands in the left half of the prostate and insertion of selectSeeds with the seedSelectron in the right half of the prostate (RS). The comparison is based on implant and target specific parameters. The implant specific parameters, V(100), homogeneity index (HI), and natural dose ratio (NDR), were determined at the time of implantation and four weeks later. MR images taken four weeks after the implantation were used for the calculation of the target specific parameters: D(90), HI, external index (EI), and conformation number (CN). RESULTS: We found no significant difference between the groups of implants (R, S, RS) for the implant specific parameters V(100), HI, and NDR at t(0) and neither at t(4w). For each group, the V(100) values decreased significantly with time between t(0) and t(4w). The target specific parameters D(90), HI, EI and CN were not significantly different between the groups. For the group of patients with both RAPID Strands and selectSeeds, we found a significant difference in D(90) between both halves of the prostate. CONCLUSIONS: The dosimetry parameters of a newly introduced implant technique using an automatic seed afterloader were not significantly different from the parameters of a manual insertion technique using RAPID Strands. Since either technique has its advantages and disadvantages regarding seed migration, physics quality assurance, efficiency, logistics, and ease of use, it was decided to use both techniques and to continue evaluations. 相似文献
108.
G Varuni Kondagunta Beverly Drucker Lawrence Schwartz Jennifer Bacik Stephanie Marion Paul Russo Madhu Mazumdar Robert J Motzer 《Journal of clinical oncology》2004,22(18):3720-3725
PURPOSE: To assess the efficacy and toxicity of bortezomib (Velcade; Milennium Pharmaceuticals Inc, Cambridge, MA; formerly PS-341) in patients with metastatic renal cell carcinoma (RCC). PATIENTS AND METHODS: Thirty-seven patients with metastatic RCC were treated with bortezomib. The first 25 patients enrolled onto the trial were treated with a dose of 1.5 mg/m2. The dose was decreased to 1.3 mg/m2 for the subsequent 12 patients, because more than 50% of the patients treated at the higher dose required dose reductions. Bortezomib was given by intravenous administration on a twice-weekly schedule for 2 weeks followed by 1 week without treatment until progression or unacceptable toxicity occurred. Twenty-three patients (62%) previously had undergone nephrectomy, and 19 patients (51%) had previously been treated with cytokine therapy. RESULTS: Of the 37 assessable patients, the best response was a partial response in four patients (11%; 95% CI, 3% to 25%) and stable disease in 14 patients (38%; 95% CI, 23% to 55%). The four patients with partial response experienced response durations of 8, 8+, 15+, and 20+ months. Grade 2 or 3 sensory neuropathy was present in 10 patients (53%) overall. One patient in the 1.5 mg/m2 group had grade 3 sensory neuropathy; no grade 3 sensory neuropathy was seen in the 1.3 mg/m2 group. CONCLUSION: The results of this trial suggest that bortezomib has an antitumor effect in individual patients with metastatic RCC. The small proportion of patients who achieved a partial response does not support routine use in metastatic RCC. Efforts to identify the molecular profile associated with clinical response or combination therapy with interferon alfa or other novel agents, may be considered. 相似文献
109.
110.
Els M J J Berns Jan G M Klijn Maxime P Look Nicolai Grebenchtchikov Rolf Vossen Harry Peters Anneke Geurts-Moespot Henk Portengen Iris L van Staveren Marion E Meijer-van Gelder Bert Bakker Fred C G J Sweep John A Foekens 《Clinical cancer research》2003,9(4):1253-1258
PURPOSE: In recent studies, we showed that TP53 gene mutation or high levels of cytosolic vascular endothelial growth factor (VEGF) in estrogen receptor (ER)-alpha-positive primary breast tumors predict a poor disease outcome for patients treated with first-line tamoxifen for advanced disease. Mutant TP53 may up-regulate VEGF, whereas, on the other hand, wild-type TP53 may decrease VEGF production. EXPERIMENTAL DESIGN: In the present study, we aimed to assess the combined predictive value of TP53 gene mutation and VEGF status of 160 advanced breast cancer patients with ER-positive tumors who were treated with tamoxifen (median follow-up from start of tamoxifen treatment, 64 months). To assess TP53 gene mutation status, the entire open reading frame was sequenced; for VEGF status, an ELISA was used. RESULTS: In univariate analysis, both TP53 gene mutation (28% of the tumors) and a VEGF level above the median value were significantly associated with a short progression-free survival, post-relapse overall survival, and a poor rate of response to tamoxifen. In Cox multivariate regression analysis including the traditional predictive factors, the addition of TP53 gene mutation and VEGF status, alone or in combination, significantly predicted a poor efficacy of tamoxifen treatment. When the two factors were combined, a significantly decreased odds ratio was seen for the rate of response (odds ratio, 0.27). Similarly, an increased hazard ratio (HR) was seen for progression-free survival (HR, 2.32) and post-relapse overall survival (HR, 1.68) in the group with mutant TP53 and high VEGF compared with the group with both risk factors absent. CONCLUSIONS: Combined TP53 gene mutation status and high VEGF levels of ER-positive primary breast tumors independently predict a poor course of the disease of patients with advanced breast cancer treated with tamoxifen. These patients, having unfavorable tumor characteristics, might benefit more from other types of (individualized) treatment protocols. 相似文献