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   1454篇
  免费   84篇
  国内免费   6篇
耳鼻咽喉   84篇
儿科学   17篇
妇产科学   46篇
基础医学   205篇
口腔科学   17篇
临床医学   97篇
内科学   340篇
皮肤病学   33篇
神经病学   137篇
特种医学   40篇
外科学   207篇
综合类   11篇
预防医学   42篇
眼科学   11篇
药学   104篇
中国医学   1篇
肿瘤学   152篇
  2023年   12篇
  2022年   28篇
  2021年   43篇
  2020年   20篇
  2019年   28篇
  2018年   30篇
  2017年   16篇
  2016年   29篇
  2015年   46篇
  2014年   51篇
  2013年   70篇
  2012年   90篇
  2011年   75篇
  2010年   60篇
  2009年   53篇
  2008年   90篇
  2007年   93篇
  2006年   80篇
  2005年   68篇
  2004年   71篇
  2003年   56篇
  2002年   62篇
  2001年   33篇
  2000年   26篇
  1999年   29篇
  1998年   16篇
  1996年   9篇
  1995年   5篇
  1992年   18篇
  1991年   13篇
  1990年   14篇
  1989年   16篇
  1988年   7篇
  1987年   16篇
  1986年   10篇
  1985年   11篇
  1984年   5篇
  1983年   12篇
  1979年   8篇
  1977年   7篇
  1974年   8篇
  1973年   25篇
  1972年   8篇
  1971年   4篇
  1970年   8篇
  1969年   7篇
  1968年   10篇
  1967年   7篇
  1966年   9篇
  1965年   5篇
排序方式: 共有1544条查询结果,搜索用时 15 毫秒
991.
Cancer patients often have an activated clotting system and are at increased risk for venous thrombosis. In the present study, we analyzed tissue factor (TF) expression in 4 different human pancreatic tumor cell lines for the purpose of producing derivative tumors in vivo. We found that 2 of the lines expressed TF and released TF-positive microparticles (MPs) into the culture medium. The majority of TF protein in the culture medium was associated with MPs. Only TF-positive cell lines activated coagulation in nude mice, and this activation was abolished by an anti-human TF Ab. Of the 2 TF-positive lines, only one produced detectable levels of human MP TF activity in the plasma when grown orthotopically in nude mice. Surprisingly, < 5% of human TF protein in plasma from tumor-bearing mice was associated with MPs. Mice with TF-positive tumors and elevated levels of circulating TF-positive MPs had increased thrombosis in a saphenous vein model. In contrast, we observed no difference in thrombus weight between tumor-bearing and control mice in an inferior vena cava stenosis model. The results of the present study using a xenograft mouse model suggest that tumor TF activates coagulation, whereas TF on circulating MPs may trigger venous thrombosis.  相似文献   
992.
Purpose

The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB.

Methods

The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used.

Results

We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA.

Conclusions

To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.

  相似文献   
993.
994.
A 72-year-old woman presented with dyspnea and lower extremity edema. Extreme lymphocytosis, cytopenia, and splenomegaly were found, and she was diagnosed with B-prolymphocytic leukemia. Following the first dose of therapy with bendamustine, the patient developed severe generalized maculopapular rash, which subsequently progressed to exuberant, non-blanching palpable purpura with hemorrhagic plaques suspicious for leukocytoclastic vasculitis. These events coincided with severe chemotherapy-induced neutropenia and thrombocytopenia, but there were no clinical symptoms of infection. Skin punch biopsy revealed perivascular and diffuse upper dermal lymphocytic infiltrate with eosinophils and marked erythrocyte extravasation consistent with a purpuric drug exanthem. The patient was treated with steroids, with complete resolution of the findings. This new form of cutaneous toxicity of bendamustine is presented along with a review of previous experience with the drug.  相似文献   
995.
996.
997.
We report the case of a 48-year-old man with acquired Fanconi syndrome due to IgG-kappa monoclonal gammopathy, who received a single dose of denosumab 60 mg for secondary prevention of skeletal fractures, in conjunction with oral calcium and vitamin D supplementation. The treatment was complicated with a severe, symptomatic hypocalcemia occurring 1 month after the injection and necessitating 4 weeks of intravenous calcium gluconate therapy. Similarly to bisphosphonates, inhibitors of the receptor activator of nuclear factor kappa-B ligand may not be appropriate for the treatment of acquired Fanconi syndrome and other forms of osteomalacia regardless of the degree of renal insufficiency and vitamin D levels. Clinicians should carefully interpret the radiographic and bone densitometry results in light of diverse mechanisms of bone demineralization and potential dependence of calcium homeostasis on high bone turnover.  相似文献   
998.

Purpose

Patient reported outcome measures play an increasingly important role in the outcomes research. The Core Outcome Measures Index (COMI) is a short, multidimensional instrument initially developed for the use by patients with low back pain. This study is an evaluation of a Polish version of COMI adapted for neck pain.

Methods

One hundred twenty-three patients complaining of neck pain were enrolled. All of them completed a questionnaire booklet containing COMI-neck, Neck Disability Index and Likert-type questions regarding the frequency of use of pain medications and pain frequency. Ninety-eight patients returned the retest questionnaire. Data quality was also assessed. Assessment of psychometric properties included examination of data quality, construct validity, test–retest reliability and factor analysis.

Results

The quality of data was good with no missing answers and a little floor effect. Exploratory factor analysis revealed a single-factor structure. Reliability expressed as intraclass correlation coefficient was 0.88 (95 % CI 0.84–0.92) for the overall COMI score and was generally good for most of individual core items. The minimum detectable change (MDC95%) was 1.97.

Conclusion

This version of the COMI-neck is a valid and reliable instrument, with good psychometric properties. It can be recommended for Polish-speaking patients.  相似文献   
999.

Objectives

The aim of the study was to assess the function of semicircular canal in videonystagmography head impulse test (VHIT) in the patients with vertigo and balance disorders.

Material and Methods

The study was performed in 135 patients (86 women and 49 men) aged 22–79 years, who were divided into 2 groups: I (study group) — 73 patients with vertigo of peripheral, central or mixed origin, II (control group) — 62 patients without vertigo (healthy individuals). The function of canal was determined on the basis of GAIN and expressed as DG/RH×100% (where DG is deviation of gaze and RH is rotation of head).

Results

In the study group the semicircular canal injuries were found in 37 (50.69%) patients, including 24 (32.87%) patients with 1 injury and 13 (17.8%) patients with 2 or more injuries in semicircular canal. The injured anterior semicircular canal was reported 13 times; the lateral — 9 times and the posterior — 31 times.

Conclusions

In the study group, in the VHIT, injuries in semicircular canals were reported in peripheral vertigo, mixed vertigo with non-compensated and compensated function of the labyrinth in 50.68% cases, whereas in the caloric test dysfunction of the labyrinth was found in 58.49% cases.  相似文献   
1000.
Short tandem repeat polymorphisms on the male‐specific part of the human Y‐chromosome (Y‐STRs) are valuable tools in many areas of human genetics. Although their paternal inheritance and moderate mutation rate (~10?3 mutations per marker per meiosis) allow detecting paternal relationships, they typically fail to separate male relatives. Previously, we identified 13 Y‐STR markers with untypically high mutation rates (>10?2), termed rapidly mutating (RM) Y‐STRs, and showed that they improved male relative differentiation over standard Y‐STRs. By applying a newly developed in silico search approach to the Y‐chromosome reference sequence, we identified 27 novel RM Y‐STR candidates. Genotyping them in 1,616 DNA‐confirmed father–son pairs for mutation rate estimation empirically highlighted 12 novel RM Y‐STRs. Their capacity to differentiate males related by 1, 2, and 3 meioses was 27%, 47%, and 61%, respectively, while for all 25 currently known RM Y‐STRs, it was 44%, 69%, and 83%. Of the 647 Y‐STR mutations observed in total, almost all were single repeat changes, repeat gains, and losses were well balanced; allele length and fathers' age were positively correlated with mutation rate. We expect these new RM Y‐STRs, together with the previously known ones, to significantly improving male relative differentiation in future human genetic applications.  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