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   1137722篇
  免费   78229篇
  国内免费   1869篇
耳鼻咽喉   15164篇
儿科学   37778篇
妇产科学   29691篇
基础医学   178311篇
口腔科学   32612篇
临床医学   100401篇
内科学   213875篇
皮肤病学   26624篇
神经病学   81350篇
特种医学   41370篇
外国民族医学   136篇
外科学   169920篇
综合类   22402篇
现状与发展   2篇
一般理论   268篇
预防医学   84681篇
眼科学   26864篇
药学   87538篇
  3篇
中国医学   3196篇
肿瘤学   65634篇
  2018年   11977篇
  2017年   9108篇
  2016年   10159篇
  2015年   11265篇
  2014年   15386篇
  2013年   23535篇
  2012年   31358篇
  2011年   33430篇
  2010年   19765篇
  2009年   18555篇
  2008年   31552篇
  2007年   33821篇
  2006年   34396篇
  2005年   32431篇
  2004年   31787篇
  2003年   30196篇
  2002年   29677篇
  2001年   56396篇
  2000年   57868篇
  1999年   47659篇
  1998年   12497篇
  1997年   10688篇
  1996年   11303篇
  1995年   10586篇
  1994年   9764篇
  1993年   9138篇
  1992年   36241篇
  1991年   36394篇
  1990年   35734篇
  1989年   35005篇
  1988年   31942篇
  1987年   31339篇
  1986年   29629篇
  1985年   28088篇
  1984年   20713篇
  1983年   17627篇
  1982年   9793篇
  1979年   19434篇
  1978年   13897篇
  1977年   11728篇
  1976年   11268篇
  1975年   12608篇
  1974年   14940篇
  1973年   14226篇
  1972年   13577篇
  1971年   12869篇
  1970年   12204篇
  1969年   11395篇
  1968年   10612篇
  1967年   9517篇
排序方式: 共有10000条查询结果,搜索用时 24 毫秒
991.
992.
993.
The importance of smoking in the aetiology of polycythaemia has been assessed in a group of patients referred to a general haematology clinic. All patients with true and relative polycythaemia (excluding those with polycythaemia rubra vera) were studied. Of the 21 such patients evaluated, 14 were smokers and had raised carboxyhaemoglobin levels and had no other demonstrable cause for their polycythaemia. The commonest physiological abnormality in these patients was a raised red cell mass combined with a low plasma volume. Six of the 14 patients were able to reduce their smoking with subsequent improvement in their haematocrits. These results suggest that smoking is a major cause of polycythaemia in an unselected series of referrals to a general haematology clinic. The early identification of these patients may be useful in planning therapy.  相似文献   
994.
Prognostic significance of serum cholesterol in nursing home men   总被引:2,自引:0,他引:2  
Serum cholesterol was measured in 129 men (average age 70.6; range 41-96) of a Veterans Administration Nursing Home, and was correlated with other items in an extensive clinical data base. Serum cholesterol was less than 150 mg/dl in 13% of the subjects, and was less than 160 mg/dl in 18%. Cholesterol greater than 280 mg/dl occurred in 8%. Serum cholesterol varied directly (p less than 0.02) with: body weight, serum albumin, serum total protein, serum sodium, ability to walk, and ability to feed oneself; and indirectly (p less than 0.02) with death rate, degree of functional dependence, and serum SGOT and LDH. Nursing home men with cholesterol less than 150 mg/dl had a death rate of 63% during the 14 months after the cholesterol analysis, compared to a death rate of 9% in men with cholesterol greater than 150 mg/dl (p less than 0.05). Death rate during the year after the analysis was 52% if cholesterol was below 160 mg/dl, compared to 7% if it was above this threshold (p less than 0.05).  相似文献   
995.
The Preferred Provider Organization concept is quickly becoming more popular because of its relative cost-effectiveness and recent successes. Managed care through means of this mental health and substance abuse PPO may well serve as the prototype for the general health care cost containment efforts of the future for the self-insured insurance plans for Alabama state employees and teachers. The first year also revealed several problems in the original proposal especially with respect to the unintended attractiveness of inpatient/residential care. Consequently, copayment plans were added to dissuade unnecessary lengthy stays (see Table 2). Second, a new quality assurance mechanism has been added to further evaluate the need for admissions to facilities, as well as for the need for continued inpatient treatment. The Alabama Quality Assurance Foundation (AQAF) began on January 1, 1988, conducting the preadmission certification on all admissions based upon criteria established jointly by AQAF and the PPO providers. In addition, AQAF will conduct continuing stay reviews at predetermined time periods to ensure that continued treatment in an inpatient setting is indeed necessary.  相似文献   
996.
We tested the effects of pre-treatment with dexamethasone on topically induced ocular anaphylaxis in the rat. Rats were immunized with dinitrophenylated Ascaris suum extract and challenged with di-DNP-lysine. Dexamethasone was administered topically once (24, 6, or 1 h before challenge) or three times (6, 4, and 2 h before challenge). A single pre-treatment given at 24 or 6 h had no significant effect. A single pre-treatment 1 h before challenge reduced the extent of edema assessed histologically but not clinically, and had no significant effect on the eosinophil count in conjunctival tissue examined 6 h after challenge. Eyes pre-treated with dexamethasone 6, 4, and 2 h before challenge showed a significant reduction in conjunctival edema assessed histologically and clinically 1 h after challenge. In addition, 6 h after challenge the number of eosinophils was significantly reduced. We conclude that repeated pre-treatment with dexamethasone can suppress both the immediate phase and the cellular late phase of topically induced ocular anaphylaxis.  相似文献   
997.
998.
285 cases of penetrating keratoplasty in whom hydrophilic bandage lenses were fitted were analyzed for the occurrence of corneal ulcers. Of these eyes 26 developed culture-proven bacterial ulcers. No correlation could be made between any particular type of contact lens and the development of corneal ulcer. Although no single factor could be delineated which may be responsible for this problem, this risk appears to be escalated where host defense mechanisms are impaired. The clinician should recognize the potential risk in using bandage lenses when the cornea is immunosuppressed and completely denervated.  相似文献   
999.
1000.
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