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   33483篇
  免费   1907篇
  国内免费   335篇
耳鼻咽喉   550篇
儿科学   349篇
妇产科学   462篇
基础医学   5565篇
口腔科学   875篇
临床医学   2675篇
内科学   6342篇
皮肤病学   1317篇
神经病学   2450篇
特种医学   2246篇
外国民族医学   1篇
外科学   4130篇
综合类   166篇
一般理论   5篇
预防医学   1579篇
眼科学   583篇
药学   3318篇
中国医学   444篇
肿瘤学   2668篇
  2024年   23篇
  2023年   244篇
  2022年   773篇
  2021年   1238篇
  2020年   559篇
  2019年   798篇
  2018年   974篇
  2017年   798篇
  2016年   1154篇
  2015年   1528篇
  2014年   1802篇
  2013年   2061篇
  2012年   3077篇
  2011年   3017篇
  2010年   1723篇
  2009年   1512篇
  2008年   2093篇
  2007年   1890篇
  2006年   1686篇
  2005年   1559篇
  2004年   1203篇
  2003年   1054篇
  2002年   896篇
  2001年   787篇
  2000年   720篇
  1999年   511篇
  1998年   201篇
  1997年   129篇
  1996年   113篇
  1995年   78篇
  1994年   90篇
  1993年   74篇
  1992年   145篇
  1991年   153篇
  1990年   171篇
  1989年   133篇
  1988年   119篇
  1987年   110篇
  1986年   93篇
  1985年   64篇
  1984年   43篇
  1983年   38篇
  1982年   28篇
  1981年   36篇
  1979年   23篇
  1978年   22篇
  1977年   23篇
  1975年   18篇
  1974年   17篇
  1970年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Novel CAR T cells targeting mesothelin (MSLN) expressed on pancreatic cancer cells were developed to overcome the limit of the clinical efficacy of CAR T cell therapy for pancreatic cancer patients. Optimal single-chain variable fragments (scFv) binding to MSLN were selected based on the binding activity and the functional effectiveness of various scFv containing CAR-expressing T cells. Engineered MSLN CAR T cells showed successful anti-tumor activity specific to MSLN expression level. Furthermore, MSLN CAR T cells were evaluated for the anti-cancer efficacy in orthotopic mouse models bearing pancreatic cancer cells, MIA Paca-2, MSLN-overexpressed MIA Paca-2 or endogenously MSLN-expressing AsPC-1. Mice were randomized into control, mock treated, MS501 BBz treated, MS501 28z treated or MS501 28BBz treated group. Mice were monitored by weekly IVIS imaging and tumors were harvested and analyzed by immunohistochemical analyses. MSLN CAR T cells produced the therapeutic effect in orthotopic animal models with complete remission in significant number of mice. Histopathological analysis indicated that CD4+ and CD8+ MSLN CAR T cells infiltrated pancreatic tumor tissue and led to cancer cell eradication. Our results demonstrated the anti-tumor efficacy of MSLN CAR T cell therapy against pancreatic cancer, suggesting its therapeutic potential.  相似文献   
942.
Fixed drug eruption (FDE) is a rare type of drug reaction that involves the skin and, less commonly, the mucosal membranes. It is characterized by clinically well-defined erythematous patches or plaques with or without blisters, which relapse at the same location if the causative agent is readministered. Tamsulosin is an alpha-1 adrenergic receptor blocker used to treat benign prostatic hyperplasia, and its common side effects are dizziness and headache. Only one case of cutaneous FDE due to tamsulosin administration has been reported but no other case of mucosal involvement has been reported to date. Therefore, we present a case of mucosal FDE caused by tamsulosin administration along with a literature review.  相似文献   
943.
Multidrug resistance (MDR) to anticancer drugs remains a serious obstacle to the success of cancer chemotherapy. Resveratrol, a polyphenol, present in natural products exerts anticancer activity and acts as a potential MDR inhibitor in various drug-resistant cancer cells. In the process of resensitization of drug-resistant cancer cells, resveratrol has been shown to interfere with ABC transporters and drug-metabolizing enzymes, increase DNA damage, inhibit cell cycle progression, and induce apoptosis and autophagy, as well as prevent the induction of epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). This review summarizes the mechanisms by which resveratrol counteracts MDR in acquired drug-resistant cancer cell lines and provides a critical basis for understanding the regulation of MDR as well as the development of MDR-inhibiting drugs.  相似文献   
944.
To better understand nutrition paradigm shift from nutrients to foods and dietary patterns, we compared associations of a nutrient-based blood cholesterol-lowering diet vs. a food-based plant-centered diet with risk of coronary heart disease (CHD) and stroke. Participants were 4701 adults aged 18–30 years and free of cardiovascular disease at baseline, followed for clinical events from 1985 and 86 to 2018. A plant-centered diet was represented by higher A Priori Diet Quality Score (APDQS). A blood cholesterol-lowering diet was represented by lower Keys Score. Proportional hazards regression was used to calculate hazard ratios (HR). Higher APDQS showed a nutrient-dense composition that is low in saturated fat but high in fiber, vitamins and minerals. Keys Score and APDQS changes were each inversely associated with concurrent plasma low-density lipoprotein cholesterol (LDL-C) change. Over follow-up, 116 CHD and 80 stroke events occurred. LDL-C predicted CHD, but not stroke. APDQS, but not Keys Score, predicted lower risk of CHD and of stroke. Adjusted HRs (95% CIs) for each 1-SD higher APDQS were 0.73 (0.55–0.96) for CHD and 0.70 (0.50–0.99) for stroke. Neither low dietary fat nor low dietary carbohydrate predicted these events. Our findings support the ongoing shift in diet messages for cardiovascular prevention.  相似文献   
945.
BackgroundMuscle cramp is possibly related to peripheral nerve hyperexcitability (PNH), and one of the most debilitating symptoms frequently encountered in patients with liver cirrhosis. We investigated whether pregabalin, a gamma-aminobutyric acid analogue, can suppress neuronal excitability and reduce muscle cramps in cirrhotic patients.MethodsWe conducted a randomized, double-blind, placebo-controlled trial in which study participants with cirrhosis from a single tertiary center were enrolled. Primary endpoint was the relative change in cramp frequency from the run-in to standard dose treatment phase (4 weeks per each). Secondary endpoints included the responder rate, and the changes in cramp frequency during sleep, pain intensity, health-related quality of life (Liver Disease Quality of Life Instrument, Short Form-36) and electrophysiological measures of PNH.ResultsThis study was terminated early because of insufficient accrual. 80% (n = 56) of the target number of participants (n = 70) were randomized to pregabalin (n = 29) or placebo (n = 27). Median baseline frequency of muscle cramps (interquartile range) was 5.8 (3.5–10) per week in the pregabalin group and 6.5 (4.0–10) in the placebo group (P = 0.970). The primary analysis showed a significant reduction in cramp frequency with pregabalin compared to placebo (−36% vs. 4.5% for the percentage change, P = 0.010). Secondary outcomes did not differ significantly between the two groups. Adverse effects with pregabalin were mainly dizziness and lethargy.ConclusionWith multiple problems emerging from premature termination in mind, the results suggested an acceptable safety profile and favorable effect of pregabalin in reducing muscle cramps compared to placebo in cirrhotic patients.Trial RegistrationClinicalTrials.gov Identifier: NCT01271660  相似文献   
946.
BackgroundThe most important aspect of a retrospective cohort study is the operational definition (OP) of the disease. We developed a detailed OP for the detection of sodium-glucose cotransporter-2 inhibitors (SGLT2i) related to diabetic ketoacidosis (DKA). The OP was systemically verified and analyzed.MethodsAll patients prescribed SGLT2i at four university hospitals were enrolled in this experiment. A DKA diagnostic algorithm was created and distributed to each hospital; subsequently, the number of SGLT2i-related DKAs was confirmed. Then, the algorithm functionality was verified through manual chart reviews by an endocrinologist using the same OP.ResultsA total of 8,958 patients were initially prescribed SGLT2i. According to the algorithm, 0.18% (16/8,958) were confirmed to have SGLT2i-related DKA. However, based on manual chart reviews of these 16 cases, there was only one case of SGLT2i-related DKA (positive predictive value = 6.3%). Even after repeatedly narrowing the diagnosis range of the algorithm, the effect of a positive predictive value was insignificant (6.3–10.0%, P > 0.999).ConclusionOwing to the nature of electronic medical record data, we could not create an algorithm that clearly differentiates SGLT2i-related DKA despite repeated attempts. In all retrospective studies, a portion of the samples should be randomly selected to confirm the accuracy of the OP through chart review. In retrospective cohort studies in which chart review is not possible, it will be difficult to guarantee the reliability of the results.  相似文献   
947.
Extranodal natural killer/T-cell lymphoma (ENKTL) is a rare but aggressive cancer characterised by angiocentric and angiodestructive infiltration by NK-cells, or cytotoxic T-cell types. Histopathologically, ENKTL shows a multinodular or diffuse infiltration localised to vascular structures, resulting in angiodestruction and necrosis. We present a patient with an initially suspected diagnosis of benign interface dermatitis with a differential diagnosis of mycosis fungoides that was later found to be an aggressive extranodal natural killer/T-cell lymphoma of a nasal type and with a dismal prognosis.  相似文献   
948.
949.
950.
Necrobiotic xanthogranuloma (NXG), is a rare multisystem disease that manifests as cutaneous inflammatory lesions, and is commonly associated with lymphoproliferative disease. Diffuse normolipemic plane xanthoma (NX), is also a rare, acquired disease that is often associated with systemic diseases such as lymphoproliferative disease. Both of these diseases have been reported to be associated with monoclonal gammopathy (MG). However, there are few cases in which these diseases co-exist. A 78-year-old female, who had a known case of NX on the neck and axillary area, presented with an asymptomatic erythematous plaque on her left supraclavicular area. Histopathological examination showed lymphoid aggregates, necrobiotic areas, and granulomatous inflammation in the dermis. Numerous foreignbody and Touton type giant cells were noticed. Serum protein immunoelectrophoresis showed an IgG kappa type MG. Lipid profile of the patient was normal. Bone marrow examination showed plasma cell myeloma. Based on these histologic and laboratory results, we diagnosed this lesion as NXG coexisting with NX and multiple myeloma. She was started on treatment with bortezomib and melphalan for multiple myeloma, and high-dose systemic corticosteroid and triamcinolone intralesional injection for the skin lesion. After 3 months of treatment, the NXG skin lesion and MG improved.  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