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   266782篇
  免费   24589篇
  国内免费   2858篇
耳鼻咽喉   913篇
儿科学   3112篇
妇产科学   6052篇
基础医学   70963篇
口腔科学   8423篇
临床医学   16436篇
内科学   56634篇
皮肤病学   4598篇
神经病学   23563篇
特种医学   5034篇
外国民族医学   14篇
外科学   18026篇
综合类   6943篇
现状与发展   25篇
一般理论   34篇
预防医学   13595篇
眼科学   3387篇
药学   25760篇
  29篇
中国医学   2612篇
肿瘤学   28076篇
  2023年   4080篇
  2022年   5300篇
  2021年   7854篇
  2020年   7408篇
  2019年   5248篇
  2018年   6445篇
  2017年   7178篇
  2016年   7687篇
  2015年   10125篇
  2014年   15395篇
  2013年   14734篇
  2012年   14357篇
  2011年   15119篇
  2010年   14010篇
  2009年   13253篇
  2008年   12021篇
  2007年   12042篇
  2006年   11361篇
  2005年   10041篇
  2004年   9481篇
  2003年   8836篇
  2002年   8608篇
  2001年   8105篇
  2000年   7601篇
  1999年   7043篇
  1998年   3427篇
  1997年   2903篇
  1996年   3284篇
  1995年   2994篇
  1994年   2469篇
  1993年   2198篇
  1992年   4385篇
  1991年   4132篇
  1990年   3742篇
  1989年   3452篇
  1988年   3306篇
  1987年   1435篇
  1986年   658篇
  1985年   1192篇
  1984年   1256篇
  1983年   1036篇
  1982年   1020篇
  1981年   935篇
  1980年   885篇
  1979年   855篇
  1978年   697篇
  1977年   566篇
  1976年   552篇
  1974年   655篇
  1973年   521篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
2.
BackgroundProximal tibia vara has drawn interest since the concept of constitutional varus was introduced. Proximal tibia vara is a condition where the knee varus tilt the tibia condyle medially and shift the tibial articular surface medially. This condition affects medial proximal tibial angle measurements and the placement of the tibial implant in knee replacement surgery. Thus, it challenged the neutral knee arthroplasty alignment target because some people may present a proximal tibia vara. This study assesses the prevalence of the proximal tibia vara and the correlation to knee osteoarthritis grade.MethodsThis retrospective study was carried out from January 2021 to June 2021. Eighty-five limbs were included with the following inclusion criteria: knee osteoarthritis patients who received a long view lower extremity radiograph. The exclusions criteria were (1) patients who had undergone arthroplasty and lower extremity surgery before and (2) valgus knee deformity. The outcomes in this study were HKAA, MAD, TAD, MPTA, PTRP, LDFA, and PTS. Intraclass correlation (ICC) using two-way mixed was used to assess the reproducibility of the radiographic parameters. Multiple logistic regression was used to evaluate the correlation between knee osteoarthritis grade and radiographs parameters (MAD and TAD).ResultA total 85 limbs from 52 patients were assessed in this study. Proximal tibia vara was found in 18 knees (21%.). The logistic regression was performed to assess the correlation between the severity of the knee osteoarthritis and radiographic parameters (MAD, TAD, LDFA, and PTS) with an overall p-value < 0.001 and pseudo-R2 = 0.29.ConclusionA significant portion of patients with knee osteoarthritis have proximal tibia vara, and it is a pre-existing condition. Since the pre-existing proximal tibia vara affects preoperative measurements, a long-standing lower extremity x-ray is recommended to be obtained as part of knee replacement preparation.  相似文献   
3.
4.
《Clinical therapeutics》2022,44(3):403-417.e6
PurposeEntecavir (ETV) and tenofovir disoproxil fumarate (TDF) are both recommended as first-line treatments for patients with chronic hepatitis B virus (CHB) infection according to international HBV treatment guidelines. However, recent studies reported conflicting results regarding the preferred antiviral in the prevention of hepatocellular carcinoma (HCC). This cohort study aimed to investigate this issue by using Taiwan's National Health Insurance Research Database, wherein a “finite” but not life-long treatment policy was applied.MethodsFrom January 2008 to December 2013, a total of 12,388 consecutive adult patients with CHB who received a finite course of TDF treatment (n = 1250) or ETV treatment (n = 11,138) were analyzed through screening for study eligibility followed by the 1:4 propensity score matching method.FindingsIn the entire cohort, the annual incidence and survival between the ETV and TDF groups were not significantly different regarding HCC occurrence (2.05 vs 2.74 per 100 patient-years [PY]; P = 0.055; hazard ratio [HR], 0.975; log-rank, P = 0.966), cirrhosis-related complications (1.9 vs 2.4 per 100 PY; P = 0.149; HR, 0.869; log-rank, P = 0.388), or all-cause mortality (2.16 vs 1.6 per 100 PY; P = 0.119; HR, 0.831; log-rank, P = 0.342), respectively. Propensity score matching analyses yielded similar results regarding HCC occurrence, cirrhosis-related complications, and all-cause mortality. In addition, these findings were consistently reproduced in the subgroups of patients with chronic hepatitis and cirrhosis that developed before antiviral treatment.ImplicationsETV and TDF did not significantly differ in prevention of HCC occurrence or reduction of cirrhosis-related complications and all-cause mortality in patients with CHB receiving a finite period of treatment.  相似文献   
5.
For supersaturating formulations of BCS-II compounds, which by definition have high intestinal permeability, a closed USP apparatus does not provide the necessary absorptive conditions during dissolution. To address this, an artificial gut simulator (AGS) has been constructed consisting of a 2.5 mL donor compartment in which a hollow fiber-based absorption module is suspended. Drug from donor diffuses across the hollow fiber membrane to be absorbed by the continuously flowing intraluminal receiver fluid. The membrane surface area and intraluminal fluid flow rate are tuned to obtain the physiologically observed absorption rate constant for a weakly basic, poorly water-soluble model compound, ketoconazole (KTZ). Supersaturated solutions of KTZ were generated in the donor in pH 6.5 phosphate buffer by the pH-shift method in the absence (closed system, control) and presence (open system, biorelevant) of an optimally or suboptimally tuned absorption module. Drug concentrations in the donor and intraluminal fluids were determined by in-line UV spectroscopy. The presence of an absorptive sink reduced the supersaturated solution's crystallization propensity, more so in the case of the optimally tuned AGS. This study demonstrates the significance of simulating absorption of drug at a physiological rate during dissolution studies, especially to predict the performance of formulations of BCS-II drugs.  相似文献   
6.
7.
8.
《Autoimmunity reviews》2022,21(9):103143
Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren’s syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.  相似文献   
9.
10.
《Cancer cell》2022,40(2):153-167.e11
  1. Download : Download high-res image (229KB)
  2. Download : Download full-size image
  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