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   7490篇
  免费   289篇
  国内免费   41篇
耳鼻咽喉   70篇
儿科学   189篇
妇产科学   115篇
基础医学   835篇
口腔科学   113篇
临床医学   385篇
内科学   1820篇
皮肤病学   94篇
神经病学   581篇
特种医学   506篇
外科学   1106篇
综合类   26篇
预防医学   212篇
眼科学   125篇
药学   476篇
  1篇
中国医学   11篇
肿瘤学   1155篇
  2023年   34篇
  2022年   69篇
  2021年   121篇
  2020年   82篇
  2019年   94篇
  2018年   91篇
  2017年   91篇
  2016年   132篇
  2015年   132篇
  2014年   141篇
  2013年   207篇
  2012年   315篇
  2011年   356篇
  2010年   201篇
  2009年   162篇
  2008年   270篇
  2007年   318篇
  2006年   316篇
  2005年   305篇
  2004年   343篇
  2003年   375篇
  2002年   370篇
  2001年   187篇
  2000年   240篇
  1999年   238篇
  1998年   106篇
  1997年   106篇
  1996年   107篇
  1995年   95篇
  1994年   88篇
  1993年   89篇
  1992年   200篇
  1991年   198篇
  1990年   216篇
  1989年   190篇
  1988年   185篇
  1987年   136篇
  1986年   133篇
  1985年   116篇
  1984年   94篇
  1983年   74篇
  1982年   52篇
  1981年   27篇
  1980年   30篇
  1979年   53篇
  1978年   39篇
  1977年   35篇
  1975年   34篇
  1974年   38篇
  1969年   25篇
排序方式: 共有7820条查询结果,搜索用时 31 毫秒
1.
The purpose of this study was to evaluate the effects of a change in the lateral anterior guidance pathway on the lateral border movement pathway of mandible. The results showed that altered occlusal guidance reproducibly and reversibly changed (increased) the lateral border movement area in two subjects who had unilaterally restricted lateral border movements.  相似文献   
2.
In vitro wear of indirect composite restoratives   总被引:3,自引:0,他引:3  
STATEMENT OF PROBLEM: Indirect composite restoratives have been improved in their wear resistance and physical properties. Several new indirect composites claim to be successfully used for full coverage crowns, but there is limited information for wear values of these new indirect composites. PURPOSE: The purpose of this study was to evaluate the wear characteristics of 7 indirect composite restoratives and to compare them with a type III gold alloy by means of an in vitro wear test. MATERIAL AND METHODS: Seven indirect composites (2 photopolymerized and 5 photo/heat-polymerized types) and a type III gold alloy (control) were used. Cylindrical Class I cavities (4-mm diameter and 3-mm depth) were prepared in occlusally flattened extracted human molars. Inlays with respective materials were fabricated on duplicated stone casts according to the manufacturers' instructions. Three types of in vitro wear tests were completed by use of the University of Alabama wear simulator. The wear tests included generalized wear as simulation of the wear during mastication, localized wear as simulation of attrition by occlusal contact, and antagonistic enamel wear, which simulated the wear of enamel created by direct contact with the restorative materials. Seven specimens were tested for each material and wear mode, and the wear depths were measured on profilometric tracings with a 2-dimensional profilometer with 1-microm accuracy. All data were analyzed by 1-way analysis of variance, and multiple comparisons were performed with Fisher's test, for which the significant level was set at.05. RESULTS: The gold alloy control exhibited a very small amount of wear in both generalized wear (0.2 +/- 0.1 microm) and localized wear (13.8 +/- 5.0 microm) as compared with all composite specimens. The antagonistic enamel wear of gold alloy was similar with the value of Sculpture. The material group, which was post polymerized or post heat-treated, included BelleGlass, Sculpture, Estenia, and Cristobal+ and showed small values ranging from 1.6 to 2.2 microm in the generalized wear. For the localized wear, Estenia exhibited the minimum value (12.8 +/- 4.9 microm) that was statistically the same as the value of the gold alloy control. However, Estenia exhibited the greatest antagonistic enamel wear value (66.0 +/- 14.0 microm) of all materials tested in this study. It was statistically significant with other materials (P相似文献   
3.
Osteoarthritis (OA) is a group of common, chronic, and painful inflammatory joint diseases. One important finding in OA patients is a remarkable decrease in the molecular weight of hyaluronic acid (HA) in the synovial fluid of affected joints. Therapeutic HA is available to patients in most parts of the world as a viscosupplementation product for the treatment of OA. Previous clinical reports show that high molecular weight HA (HMWHA) more effectively relieves pain than low molecular weight HA (LMWHA). However, the mechanism behind this finding remains unclear. In this study, we investigated whether a LMWHA (Low‐0.9 MDa) and two types of HMWHA (High‐1.9 MDa and 6 MDa) differentially affected chondroregulatory action. We tested this using ATDC5 cell, a murine chondrocytic cell line widely used in culture systems to study chondrogenic differentiation. We found that HMWHA, especially hylan G‐F 20 (High‐6 MDa), significantly induced aggrecan and proteoglycan accumulation, nodule formation, and mRNA expression of chondrogenic differentiation markers in a time‐ and dose‐dependent manner. In addition, we showed that HMWHA prevented TNF‐α induced inhibition of chondrogenic differentiation, with no effect on cell proliferation or viability. These results reveal that HMWHA significantly promotes chondrogenic differentiation of ATDC5 cells in vitro, and suggest that HMWHA plays a significant chondroregulatory role in vivo. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1619–1627, 2014.  相似文献   
4.
The anti-inflammatory effect of erythromycin was investigated using zymosan-induced peritonitis in mice. When mice were given erythromycin 10 mg/kg/day po for 28 days, a marked suppression of inflammatory responses, including the reduced influx of leucocytes, plasma exudation and prostaglandin E2 synthesis, was observed. However, neither a 7-day treatment with erythromycin nor a 28-day treatment with clindamycin suppressed the response. The anti-inflammatory activity induced after a 28-day treatment with erythromycin was comparable to the anti-inflammatory effect conferred by a 2-day treatment with dexamethasone 40 microgram/mouse/day. Thus, these data confirm previous studies which show that erythromycin can exert an anti-inflammatory effect when used over long periods of time.  相似文献   
5.
6.
Miho Shimizu  Kengo Furuichi  Tadashi Toyama  Tomoaki Funamoto  Shinji Kitajima  Akinori Hara  Daisuke Ogawa  Daisuke Koya  Kenzo Ikeda  Yoshitaka Koshino  Yukie Kurokawa  Hideharu Abe  Kiyoshi Mori  Masaaki Nakayama  Yoshio Konishi  Ken-ichi Samejima  Masaru Matsui  Hiroyuki Yamauchi  Tomohito Gohda  Kei Fukami  Daisuke Nagata  Hidenori Yamazaki  Yukio Yuzawa  Yoshiki Suzuki  Shouichi Fujimoto  Shoichi Maruyama  Sawako Kato  Takero Naito  Kenichi Yoshimura  Hitoshi Yokoyama  Takashi Wada  Research Group of Diabetic Nephropathy  the Ministry of Health  Labour    Welfare of Japan  Japan Agency for Medical Research  Development 《Clinical and experimental nephrology》2018,22(2):377-387

Background

There is increased interest in surrogate endpoints for clinical trials of chronic kidney disease.

Methods

In this nationwide observational study of 456 patients with type 2 diabetes and clinically suspected diabetic nephropathy followed for a median of 4.2 years, we evaluated the association between estimated glomerular filtration rate (eGFR) and albuminuria at baseline or during follow-up and risk of ESRD.

Results

Low eGFR (<60 mL/min/1.73 m2) and macroalbuminuria at enrollment were independently associated with risk of ESRD. In patients with macroalbuminuria, both ≤?50% change and ?50 to ?30% change in eGFR over 1 and 2 years were predictive of ESRD. The higher cut point (≥50% decline in eGFR) was more strongly predictive but less common. Remission of macroalbuminuria to normo-/microalbuminuria at 1 and 2 years was associated with a lower incidence of ESRD than no remission; however, it was not a determinant for ESRD independently of initial eGFR and initial protein-to-creatinine ratio.

Conclusion

These results suggest that a ≥30% decline in eGFR over 1 or 2 years adds prognostic information about risk for ESRD in patients with type 2 diabetes and macroalbuminuria, supporting the consideration of percentage decline in eGFR as a surrogate endpoint among macroalbuminuric cases in type 2 diabetes. On the other hand, our study suggests that additional analyses on the relationship between remission of macroalbuminuria and risk of ESRD are needed in type 2 diabetes.
  相似文献   
7.
Flying foxes belonging to the genus Pteropus are known to be reservoirs of zoonotic viruses. In this study, we describe the isolation of Pteropine orthoreovirus (PRV) from rectal swab samples of Pteropus vampyrus in Indonesia. PRV is an emerging zoonotic respiratory virus that can be transmitted from bats to humans. Rectal swabs (n?=?91) were screened by PCR for PRV and 10 (11%) were positive. Phylogenetic analysis based on nucleotide sequences indicated that the S2, S3, S4, M3, L2, and L3 segments of one isolate (Garut-69) were closely related to previously isolated strains in Indonesia. The remaining gene segments showed both similarity and genetic divergence with other PRV strains, suggesting that re-assortment events had occurred. This is the first report of PRV infection to P. vampyrus in West Java, Indonesia.  相似文献   
8.
9.
Annals of Surgical Oncology - Transient receptor potential vanilloid 2 (TRPV2) is a highly Ca2+-permeable ion channel that is involved in a number of cellular processes. It is expressed in various...  相似文献   
10.
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