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   1181篇
  免费   96篇
  国内免费   6篇
耳鼻咽喉   22篇
儿科学   37篇
妇产科学   14篇
基础医学   162篇
口腔科学   12篇
临床医学   137篇
内科学   240篇
皮肤病学   3篇
神经病学   187篇
特种医学   35篇
外科学   91篇
综合类   27篇
一般理论   1篇
预防医学   125篇
眼科学   4篇
药学   103篇
中国医学   2篇
肿瘤学   81篇
  2022年   14篇
  2021年   20篇
  2018年   18篇
  2017年   14篇
  2015年   13篇
  2014年   26篇
  2013年   21篇
  2012年   47篇
  2011年   57篇
  2010年   20篇
  2009年   35篇
  2008年   49篇
  2007年   48篇
  2006年   43篇
  2005年   48篇
  2004年   48篇
  2003年   48篇
  2002年   43篇
  2001年   44篇
  2000年   30篇
  1999年   36篇
  1998年   17篇
  1997年   18篇
  1995年   11篇
  1994年   11篇
  1993年   12篇
  1992年   38篇
  1991年   26篇
  1990年   23篇
  1989年   26篇
  1988年   24篇
  1987年   15篇
  1986年   23篇
  1985年   24篇
  1984年   13篇
  1983年   10篇
  1982年   12篇
  1981年   13篇
  1980年   14篇
  1979年   17篇
  1978年   13篇
  1977年   14篇
  1976年   16篇
  1974年   11篇
  1973年   14篇
  1972年   14篇
  1971年   17篇
  1970年   18篇
  1969年   15篇
  1966年   13篇
排序方式: 共有1283条查询结果,搜索用时 19 毫秒
61.
The Wilson procedure for correction of hallux abducto valgus is modified for use in three specific clinical conditions. The modifications are outlined and demonstrated in the preoperative conditions of 1) juvenile hallux abducto valgus, 2) functional hallux limitus, and 3) postoperative metatarsus primus elevatus. The rationale and biomechanical considerations for the modified Wilson bunion procedure are discussed.  相似文献   
62.
63.
64.
Mice injected intranasally (it.n.) and intraperitoneally (i.p.) with a nonlethal dose (2.5 x 10(5) colony-forming units) of live Bordetella pertussis were examined for 50 days for infection, respiratory tract immunoglobulins (Ig), changes in serum Ig, and histamine sensitivity. With mice infected it.n., respiratory infection markedly declined between day 20 and day 30. Ig classes (A, G(1), G(2a), G(2b), but no M), which had specificity for B. pertussis, were present in tracheobronchial wash (TBW) by day 15; by day 50, TBW immunodiffusion and immunoelectrophoretic precipitin bands were more intense. A sharp rise in serum IgA after day 30 was the only significant change relative to controls among the five serum Ig examined. A high degree of histamine sensitivity developed by day 15 to 20 and persisted for the 50 days. With mice inoculated i.p., no bacteria were recovered, no Ig or only traces were found in TBW and IgA only was specific, and no significant changes in the serum Ig relative to controls occurred. Histamine sensitivity developed somewhat more slowly and to a lesser degree than in it.n.-injected mice but persisted for the 50 days. A similar small number of killed bacteria (pertussis vaccine) injected it.n. or i.p. likewise induced slowly developing histamine sensitivity in contrast to published reports of 4 to 5 day peak sensitivity and decline following i.p. injection of 10(9) or more killed bacteria.  相似文献   
65.
66.
Relationship betrayals, such as sexual and emotional infidelity, are commonly encountered in the practice of psychotherapy, yet clinicians often report difficulties in assessing and treating them. In this article we offer suggestions for assessing relationship betrayals. We address the definition of relationship betrayals, methods of assessing relationship betrayals, when and whom to assess, confidentiality, and assessing related clinical concerns. We illustrate with case vignettes the assessment and treatment of betrayals in close relationships.  相似文献   
67.
OBJECTIVE: The authors present a Measurement and Analysis System for Capillary Oxygen Transport (MASCOT) to study red blood cell (RBC) dynamics and oxygenation in capillary networks. The system enables analysis of capillaries to study geometry and morphology and provides values for capillary parameters such as diameter and segment length. It also serves as an analysis tool for capillary RBC flow characteristics, including RBC velocity, lineal density, and supply rate. Furthermore, the system provides a means of determining the oxygen saturation of hemoglobin contained within RBCs, by analysis of synchronized videotapes containing images at two wavelengths, enabling the quantification of the oxygen content of individual RBCs. METHODS: Video recordings of RBC flow at two wavelengths, 420 nm (isosbestic) and 436 nm (oxygen sensitive), are made using a dual camera video microscopy system. The 420-nm recording is used to generate images based on the variance of light intensity fluctuations that help to identify capillaries in a given field of view that are in sharp focus and exhibit flow of individual RBCs separated by plasma gaps. A region of interest enclosing the desired capillary is defined and a fixed number of successive video frames at the two wavelengths are captured. Next a difference image is created, which delineates the RBC column, whose width is used to estimate the internal diameter of the capillary. The 420-nm images are also used to identify the location and centroid of each RBC within the capillary. A space-time image is generated to compute the average RBC velocity. Lineal density is calculated as the number of RBCs per unit length of a capillary segment. The mean optical density (OD) of each RBC is calculated at both wavelengths, and the average SO(2) for each cell is determined from OD(436)/OD(420). RESULTS AND CONCLUSIONS: MASCOT is a robust and flexible system that requires simple hardware, including a SGI workstation fitted with an audio-visual module, a VCR, and an oscilloscope. Since the new system provides information on an individual cell basis from entire capillary segments, the authors believe that results obtained using MASCOT will be more accurate than those obtained from previous systems. Due to its flexibility and ease of extension to other applications, MASCOT has the potential to be applied widely as an analysis tool for capillary oxygen transport measurements.  相似文献   
68.
69.
Embryos were immobilized with neuromuscular blocking agents for one to four days between days 10 and 15 of incubation. This treatment reduces spontaneous motility, as well as movement-initiated proprioceptive and cutaneous stimulation. Although the major aim of these experiments was to determine the effects of such treatment on subsequent behavioral development, several indices of neuromuscular and general morphological development were also examined. A single injection of curare on day 10 continues to depress spontaneous motility for virtually the entire remaining incubation period. This effect is due to the persistence of unmetabolized curare in the closed system of the egg. When a comparable dose of a rapidly metabolized neuromuscular blocking agent (succinylcholine) is given, this long term behavioral depression is not found. Embryos treated with SC can remain totally immobilized for up to 60 hours with no apparent repercussions on subsequent behavior; spontaneous embryonic motility, reflex sensitivity, hatching, and several general posthatching behaviors, all appeared normal following such treatment. Embryos immobilized for as little as 48 hours developed joint malformations and were retarded in general growth by about one day whereas 24 hours of paralysis was not sufficient to induce these effects. Twenty-four hours of total paralysis from days 10 to 11, plus a 40–50% reduction in motility until days 15 or 16, does not appear to cause any abnormalities in muscle or spinal cord development. Muscle histology, motor endplates, cell number in the spinal cord and choline acetyltransferase and acetylcholinesterase activity in spinal cord and muscle were all comparable to controls. An 80–90% reduction in motility on days 11 through 15, however, induces an apparent alteration of the intensity and distribution of histochemically demonstrable AChE in the anterior and posterior latissimus dorsi muscles. The present findings suggest that the suppression of overt motility for a period comprising ca. 5–12% of the total incubation time (21 days) does not modify subsequent behavioral development or the underlying neurogenetic mechanisms. Though these findings provide some support for the notion that the embryonic nervous system develops in forward reference to and without benefit from function or sensory input, only a more complete reduction of neural function, especially CNS activity, can provide a critical test of this concept.  相似文献   
70.
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