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   1441篇
  免费   77篇
  国内免费   12篇
耳鼻咽喉   3篇
儿科学   46篇
妇产科学   12篇
基础医学   118篇
口腔科学   22篇
临床医学   90篇
内科学   305篇
皮肤病学   49篇
神经病学   20篇
特种医学   104篇
外科学   127篇
综合类   274篇
预防医学   72篇
眼科学   42篇
药学   89篇
中国医学   9篇
肿瘤学   148篇
  2023年   9篇
  2022年   24篇
  2021年   30篇
  2020年   27篇
  2019年   21篇
  2018年   36篇
  2017年   26篇
  2016年   25篇
  2015年   55篇
  2014年   27篇
  2013年   46篇
  2012年   45篇
  2011年   37篇
  2010年   58篇
  2009年   56篇
  2008年   55篇
  2007年   78篇
  2006年   72篇
  2005年   53篇
  2004年   72篇
  2003年   41篇
  2002年   46篇
  2001年   28篇
  2000年   38篇
  1999年   41篇
  1998年   47篇
  1997年   53篇
  1996年   55篇
  1995年   34篇
  1994年   34篇
  1993年   15篇
  1992年   18篇
  1991年   17篇
  1990年   17篇
  1989年   16篇
  1988年   19篇
  1987年   13篇
  1986年   12篇
  1985年   9篇
  1984年   15篇
  1983年   8篇
  1982年   10篇
  1981年   11篇
  1980年   8篇
  1978年   9篇
  1975年   8篇
  1974年   6篇
  1973年   7篇
  1971年   7篇
  1967年   8篇
排序方式: 共有1530条查询结果,搜索用时 0 毫秒
71.
A study was undertaken to determine the usefulness of ultrasonography as an investigative tool, and its role in deciding the management of Peyronie's disease. Fifteen patients with Peyronie's disease were studied by ultrasonography. The plaque could be demonstrated in all patients. The dimensions of the plaque varied from less than 1 cm to more than 7cm in length and 2-4mm in thickness. The disease was active in 26% of the patients, as indicated by the presence of hypoechoic areas around a central region of hyperechoism. Ultrasonogram was more accurate than clinical assessment in delineating the extent of lesions. In one-third of the patients, sonography demonstrated the plaques to be more extensive than had been detected by clinical examination. Calcification and activity of disease (which are clearly defined by ultrasonogram) are determining factors in the management of Peyronie's disease. This information allows the surgeon to select the modality of treatment, the timing of surgery and extent of excision. Thus, ultrasonography plays a vital role in the preliminary investigation and management of Peyronie's disease.  相似文献   
72.
OBJECTIVE: Autoantibodies observed in patients with rheumatoid arthritis (RA) during clinical trials of immunomodulating agents may cause concern about possible induction of autoimmunity by the therapeutic intervention. We determined the frequency and variability of selected autoantibodies in patients with early rheumatoid factor (RF) positive RA during a prospective observational study. METHOD: The study cohort consisted of 276 patients with active RA and with RF > or = 40 IU, who were enrolled between January 1, 1993, and April 1, 2000, before starting disease modifying antirheumatic drug (DMARD) therapy (average duration of symptoms, 7 mo). During an average of 3.5 years followup, a panel of autoantibodies was determined at entry, 6 months, 12 months, and yearly thereafter, in addition to routine clinical, radiographic, and laboratory assessments. After enrollment, patients were treated with DMARD at the discretion of their rheumatologists. RESULTS: At entry before any DMARD therapy, antinuclear antibody (ANA; by HEp-2) values were negative in 31%, borderline (8 IU/ml) in 26%, and > 8 (mean 65.5 IU/ml) in 41%. Tender and swollen joint counts, Disease Activity Score, and RF values were significantly higher in those with ANA > 8. During followup 726 paired serial specimens were available; 12.5% changed from negative to positive ANA and 12.3% from positive to negative. Additional autoantibodies were present in specimens of 20% of the subjects; 8% had 2 and 1.4% had 3 other autoantibodies. Anti-dsDNA was detected in 13 (5.5%) patients; 4 changed from negative to positive and one from positive to negative. SSA IgG and SSB IgG autoantibodies were both present in one of these patients. Ribosomal P protein autoantibodies were noted in 2 other patients, but Sm (Smith) and uRNP/snRNP IgG autoantibodies were not present in any patient. No patient had a diagnosis of systemic lupus erythematosus. Antithyroid peroxidase (20 patients), parietal cell (15), smooth muscle (14), reticulin (9), mitochondrial (5), striational (2), SSB (2) and SCL-70 (1) autoantibodies were detected in some specimens. Seven patients were diagnosed with hypothyroidism, one with chronic thyroiditis, one with hepatitis C, and 9 with malignancies. CONCLUSION: In patients with early RF positive RA the frequent occurrence of autoantibodies before and during treatment with standard DMARD may make it difficult to attribute their presence to new therapies.  相似文献   
73.
74.
PURPOSE: To assess the feasibility of administering erlotinib, an inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, in combination with paclitaxel and carboplatin, and to identify pharmacokinetic interactions, evaluate downstream effects of EGFR inhibition on surrogate tissues, and seek preliminary evidence for clinical activity. EXPERIMENTAL DESIGN: Patients with advanced solid malignancies were treated continuously with erlotinib at doses of 100, 125, and 150 mg/d orally along with fixed i.v. doses of paclitaxel 225 mg/m(2) and carboplatin AUC 6 mg x min/mL, both on day 1 every 3 weeks. RESULTS: Twenty evaluable patients were treated with 136 courses of erlotinib, paclitaxel, and carboplatin. Myelosuppression, skin rash, and diarrhea were the principal toxicities. Dose limiting diarrhea occurred in 1 of 6 patients at the 100 mg erlotinib dose level, whereas 0 of 9 evaluable patients at the 125 mg erlotinib dose level experienced dose limiting toxicity and 3 of 5 evaluable patients at 150 mg erlotinib experienced dose limiting skin rash and neutropenic sepsis. There was no evidence of pharmacokinetic interactions between paclitaxel and erlotinib; however, total carboplatin exposure trended higher in the presence of erlotinib. No consistent downstream effects on EGFR inhibition were found in skin. Durable objective responses were observed in non-small-cell lung and head and neck cancers. CONCLUSIONS: A dose level of erlotinib 125 mg combined with paclitaxel 225 mg/m(2) and carboplatin AUC 6 mg.min/mL is recommended for disease-directed studies. This phase I trial was followed by a randomized phase III study in non-small-cell lung cancer using a similar regimen.  相似文献   
75.
Leiomyoma of the vagina is a very rare tumour of the lower urogenital tract. These slow‐growing masses may be asymptomatic or present with pain, dyspareunia or urinary symptoms. Rarely, these tumours may present with life‐threatening haemorrhage. These hypervascular tumours are treated by surgical excision. Preoperative embolization therefore may aid in devascularization of these tumours before surgical excision. We present the MRI features of a case of vaginal leiomyoma, which was managed by preoperative embolization and was then excised in toto. To the best of our knowledge, this is the first report where preoperative embolization was performed before excision of a vaginal leiomyoma with minimal peroperative blood loss.  相似文献   
76.
Paracetamol is the commonest agent employed in self poisoning, however it is not clear whether adolescents possess insight into the serious complications associated with its misuse. Using a one page questionnaire, the availability, usage, and knowledge of toxicity of paracetamol among 1147 American and British adolescents was assessed. Although 90% of all students recognised that paracetamol could kill, the great majority of students overestimated the lethal dose. In addition, while knowledge regarding side effects of paracetamol was poor the drug was widely available to, and used by, the study population. It is proposed that gross overestimation of the number of tablets required to kill, poor understanding of paracetamol side effects, and wide availability of the drug contribute to its frequent use in adolescent suicidal behaviour. The inclusion of some over-the-counter medications in school drug education programs in addition to tighter control of the availability of paracetamol may help reduce the problem of adolescent self poisoning.  相似文献   
77.
Purpose. The FDA has proposed replacing the current averagebioequivalence criterion with population and individual bioequivalence criteriathat consider variances in addition to the difference of averages. Oneof these variances in the individual bioequivalence criterion measuressubject-by-formulation interaction, the extent to which thetest-reference difference varies from person to person. This paper discussesconceptual and statistical issues raised in various publications andpresentations with respect to the presence and estimation of such aninteraction. Methods. We focus on the importance of subject-by-formulationinteraction, an understanding of what is a large interaction, and theassessment of the magnitude of this interaction in bioequivalence studies.Simulation studies, examples from the literature, and data from FDAfiles are used to demonstrate the magnitude of the interaction and itsdistribution under various conditions. Results. The concept of a large interaction is tied to the concept of alarge mean difference. We suggest that an interaction greater than0.15 is a conservative criterion for a large interaction. Magnitudes ofestimated interaction are affected by variability, sample size, and theselection of data sets that pass average bioequivalence. Conclusions. Examples of substantial interactions are beginning toappear. More data is needed before reaching definitive conclusionsregarding the frequency and importance of observed interactions.  相似文献   
78.
79.
80.
Eleven women with a history of infertility and uterine leiomyomas underwent magnetic resonance (MR) imaging of the pelvis prior to myomectomy. Nine also underwent preoperative pelvic ultrasonography (US), and ten underwent hysterosalpingography. All studies were interpreted prospectively by independent observers. With each imaging modality, the location (one of 11 anatomic segments), size, and appearance of detected uterine leiomyomas were determined and compared with surgical and histologic findings. Among the nine patients who underwent both MR and US, the sensitivity (85%) and accuracy (94%) of MR imaging for abnormal segments was significantly better than that of US (sensitivity = 69%, P = .015; accuracy = 87%, P = .043). For the ten patients who underwent both MR and hysterosalpingography, the sensitivity (91%) and accuracy (96%) of MR imaging was better than that of hysterosalpingography (sensitivity = 18%, P = .0005; accuracy = 72%, P = .0005). The specificities of the three modalities did not significantly differ (100%, 97%, and 98% for MR, US, and hysterosalpingography, respectively). These data suggest that MR imaging is superior to US or hysterosalpingography for preoperatively locating uterine leiomyomas.  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