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   2172篇
  免费   203篇
  国内免费   12篇
耳鼻咽喉   38篇
儿科学   48篇
妇产科学   64篇
基础医学   372篇
口腔科学   51篇
临床医学   217篇
内科学   567篇
皮肤病学   11篇
神经病学   265篇
特种医学   64篇
外科学   243篇
综合类   32篇
一般理论   1篇
预防医学   99篇
眼科学   51篇
药学   123篇
  1篇
中国医学   1篇
肿瘤学   139篇
  2022年   15篇
  2021年   54篇
  2020年   37篇
  2019年   47篇
  2018年   64篇
  2017年   44篇
  2016年   52篇
  2015年   51篇
  2014年   66篇
  2013年   86篇
  2012年   127篇
  2011年   104篇
  2010年   62篇
  2009年   70篇
  2008年   119篇
  2007年   110篇
  2006年   116篇
  2005年   102篇
  2004年   96篇
  2003年   99篇
  2002年   76篇
  2001年   26篇
  2000年   25篇
  1999年   37篇
  1998年   23篇
  1997年   13篇
  1996年   21篇
  1995年   20篇
  1993年   12篇
  1992年   39篇
  1991年   43篇
  1990年   18篇
  1989年   22篇
  1988年   25篇
  1987年   34篇
  1986年   44篇
  1985年   28篇
  1984年   41篇
  1983年   26篇
  1982年   14篇
  1981年   15篇
  1980年   15篇
  1979年   32篇
  1978年   25篇
  1977年   20篇
  1976年   17篇
  1975年   21篇
  1974年   18篇
  1973年   29篇
  1970年   12篇
排序方式: 共有2387条查询结果,搜索用时 15 毫秒
1.
OBJECTIVE: Intramuscular (i.m.) ziprasidone treatment has been shown to be effective and well tolerated in reducing the symptoms of acute psychosis in adults. Few data are available as to safety in the elderly. The growing utilization of health services by elderly psychiatric patients warrants an evaluation in this population. METHOD: Consecutive elderly patients (60 years of and older) admitted to a psychogeriatric ward in a large, university-affiliated tertiary psychiatric center were treated by i.m. ziprasidone for acute psychotic agitation. Patients received three days of flexible-dose i.m. ziprasidone. After an initial dose of 10-20 mg, a subsequent dose of 10-20 mg could be given after 12 hours if needed (maximum daily dose: 40 mg). RESULTS: All treatment emergent side effects and adverse events along with the investigators' assessments of severity were systematically recorded as the primary outcome. The Brief Psychiatric Rating Scale (BPRS) and the Behavioral Activity Rating Scale (BARS) were the secondary outcomes. Twenty-one patients, six male and 15 female, mean age 71.4 +/- 1.3 years (range: 60-81 years) were enrolled. All had completed the three days i.m. ziprasidone treatment. There was one adverse event in a patient with untreated benign prostatic hypertrophy who developed urinary retention. Two side effects of mild severity that resolved spontaneously were observed: blurred vision and sedation. The BPRS decreased by 26.8 points after three days of treatment (p = 0.001). The BARS score, reflecting agitation, decreased significantly after each injection, reaching maximal decrease of 2.14 points at completion of study (p = 0.001). CONCLUSION: Intramuscular ziprasidone in this series of elderly patients suggests acceptable safety and efficacy in the management of acute psychotic agitation among elderly patients with schizophrenia.  相似文献   
2.
Absence of antibody production in patients treated with botulinum A toxin   总被引:4,自引:0,他引:4  
To test the possibility of the formation of an antibody to botulinum A toxin after multiple injections of this potent neurotoxin, we collected serum samples from 28 patients who received 57 doses. These injections over a nine-month period with as much as 50 units per injection formed no detectable antibody.  相似文献   
3.
Thirty-three patients with primary gastrointestinal lymphoma (GIL) followed at Ankara University Medical School have been evaluated. The most frequent locations of the disease are the small intestine (48.4%) and the stomach (39.3%). The intermediate and high grade lymphomas constitute 84.8% of the cases. The mean age of the patients with small intestinal lymphoma is 28.7 years and 47.1 years for those with gastric lymphoma. The patients treated with surgery and chemotherapy (S+CT) have a longer survival than those treated with chemotherapy (CT) alone. In conclusion: 1) Small intestinal lymphoma occurs more frequently than gastric lymphoma in our study. 2) The median age of the Turkish patients with primary GIL is approximately 10 years less than those in the Western countries. 3) The therapeutic results of S+CT are superior to those of CT in the early stages of the disease.  相似文献   
4.
OBJECTIVES: To investigate variation among neonatal intensive care units (NICUs) in prevalence and management of thrombocytopenia in infants <1500 g. STUDY DESIGN: In total 1283 infants &<1500 g admitted to six NICUs over 21 months were prospectively analyzed. Illness severity was measured by the Score for Neonatal Acute Physiology (SNAP). Platelet counts in the first 12 hours after birth and on day 3 of life were abstracted from the infants' medical records. Thrombocytopenia was determined from the lowest platelet count in each of these time periods. RESULTS: There was variability in rates of thrombocytopenia among NICUs, even after controlling for risk factors (e.g., SNAP, small for gestational (SGA) age and maternal hypertension). One site had a high prevalence of thrombocytopenia, but the lowest percentage of infants with thrombocytopenia who received platelet transfusions. After controlling for SNAP, GA, SGA, Apgar score and incidence of thrombocytopenia, the odds of receiving platelets at this site, relative to the site with the highest transfusion rate, was 0.10 (95% CI 0.02 to 0.43). CONCLUSIONS: This multicenter study finds a 10-fold variation among NICU in the administration of platelets to their thrombocytopenic infants that cannot be explained by presence of thrombocytopenia or illness severity.  相似文献   
5.
Extradural lymphoma can present as an acute neurosurgical emergency. The clinical presentation and radiological appearance may suggest epidural hematoma or meningioma. Lymphoma should be considered as a rare but possible diagnosis before operation. High resolution computed tomography using direct coronal imaging with and without contrast enhancement may aid in suggesting the correct preoperative diagnosis.  相似文献   
6.
Mitogen-stimulated interleukin-2 (IL-2) production was measured in 122 patients who met Research Diagnostic Criteria for schizophrenia and 98 normal control subjects. The presence of autoantibodies against seven common antigens was also determined. There was no relationship between the presence of circulating autoantibodies and IL-2 production in control subjects. In patients, however, autoantibody-positive, acutely ill patients had significantly lower IL-2 production as compared with other patients and control subjects. Never-medicated patients showed the same trends for decreased IL-2 production in association with autoantibodies. These data suggest that decreased IL-2 production is associated with acute illness in schizophrenic patients who produce autoantibodies, a trait known to be associated with increased vulnerability to autoimmune disease.  相似文献   
7.
Studies describing sexually transmitted disease (STD) and human immunodeficiency virus (HIV) prevention practices of primary care physicians have relied on physician or patient reports. This study describes physician STD/HIV prevention practices as observed by unannounced simulated patient evaluators (SPEs). SPEs visited sixty-five primary care physicians. Each SPE portrayed a sexually active female, new to the area, requesting a consultation on STD prevention. One-third of the physicians in the study asked no risk questions, and over 80% failed to ask the SPE specifically about her sexual practices. Most physicians discussed the risks of STDs and HIV and covered basic recommendations (use condoms and know partners better); however, few physicians provided any individualized information or advice about safer sexual practices and the specifics of condom use, such as how to use them or what kind to use. These observations support the low rates of STD/HIV prevention indicated in physicians' self-report and further identify specific deficiencies in the thoroughness of their risk assessment and preventive counseling practices.  相似文献   
8.
Beta-lactam resistance in Pseudomonas aeruginosa detected only during ceftazidime therapy of cystic fibrosis patients was studied. Evaluation of resistant and susceptible isolates from one patient and resistant laboratory derivatives indicated that elevated beta-lactamase levels were the primary determinant of resistance. Susceptible isolates outgrew resistant isolates on antibiotic-free medium.  相似文献   
9.
To assess DNA immunization as a strategy for protecting against HIV infection in humans, we utilized SIVmne infection of Macaca fascicularis as a vaccine challenge model with moderate pathogenic potential. We compared the efficacy of DNA immunization alone and in combination with subunit protein boosts. All of the structural and regulatory genes of SIVmne clone 8 were cloned into mammalian expression vectors under the control of the CMV IE-1 promoter. Eight M. fascicularis were immunized twice with 3 mg of plasmid DNA divided between two sites; intramuscular and intradermal. Four primed macaques received a further two DNA immunizations at weeks 16-36, while the second group of four were boosted with 250 microg recombinant gp160 plus 250 microg recombinant Gag-Pol particles formulated in MF-59 adjuvant. Half of the controls received four immunizations of vector DNA; half received two vector DNA and two adjuvant immunizations. As expected, humoral immune responses were stronger in the macaques receiving subunit boosts, but responses were sustained in both groups. Significant neutralizing antibody titers to SIVmne were detected in one of the subunit-boosted animals and in none of the DNA-only animals prior to challenge. T-cell proliferative responses to gp160 and to Gag were detected in all immunized animals after three immunizations, and these responses increased after four immunizations. Cytokine profiles in PHA-stimulated PBMC taken on the day of challenge showed trends toward Thl responses in 2/4 macaques in the DNA vaccinated group and in 1/4 of the DNA plus subunit vaccinated macaques; Th2 responses in 3/4 DNA plus subunit-immunized macaques; and Th0 responses in 4/4 controls. In bulk CTL culture, SIV specific lysis was low or undetectable, even after four immunizations. However, stable SIV Gag-Pol- and env-specific T-cell clones (CD3+ CD8+) were isolated after only two DNA immunizations, and Gag-Pol- and Nef-specific CTL lines were isolated on the day of challenge. All animals were challenged at week 38 with SIVmne uncloned stock by the intrarectal route. Based on antibody anamnestic responses (western, ELISA, and neutralizing antibodies) and virus detection methods (co-culture of PBMC and LNMC, nested set PCR- of DNA from PBMC and LNMC, and plasma QC-PCR), there were major differences between the groups in the challenge outcome. Surprisingly, sustained low virus loads were observed only in the DNA group, suggesting that four immunizations with DNA only elicited more effective immune responses than two DNA primes combined with two protein boosts. Multigenic DNA vaccines such as these, bearing all structural and regulatory genes, show significant promise and may be a safe alternative to live-attenuated vaccines.  相似文献   
10.
Although magnetic resonance imaging (MRI) represents the most sensitive tool for the detection of white matter abnormalities in patients with multiple sclerosis (MS), the heterogeneity of MS placques severely hampers the elucidation of specific pathophysiological processes. In order to identify putative MRI markers for de- and remyelination, we employed the cuprizone mouse model which leads to a selective and reversible demyelination of the corpus callosum with little or no axonal damage. Apart from histopathology, animals were studied with high-resolution three-dimensional MRI in vivo using multiple contrasts. While individual MRI findings significantly correlated with electron microscopy, the differentiation of regions with normal, demyelinated or remyelinated white matter by one contrast alone was less specific than by histology or electron microscopy. However, an accurate MRI prediction of the in vivo myelin status was achieved by a discriminant function analysis using a combination of T1, T2 and magnetization transfer contrast. With a correct assignment of 95% of all animals examined, the procedure will allow for the survey of new therapeutic approaches aiming at improved remyelination.  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