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   9208篇
  免费   686篇
  国内免费   27篇
耳鼻咽喉   143篇
儿科学   231篇
妇产科学   345篇
基础医学   1498篇
口腔科学   146篇
临床医学   842篇
内科学   1822篇
皮肤病学   124篇
神经病学   822篇
特种医学   376篇
外科学   999篇
综合类   60篇
一般理论   4篇
预防医学   825篇
眼科学   96篇
药学   823篇
中国医学   14篇
肿瘤学   751篇
  2021年   99篇
  2020年   62篇
  2019年   111篇
  2018年   136篇
  2017年   75篇
  2016年   100篇
  2015年   135篇
  2014年   206篇
  2013年   294篇
  2012年   419篇
  2011年   470篇
  2010年   235篇
  2009年   220篇
  2008年   438篇
  2007年   444篇
  2006年   462篇
  2005年   470篇
  2004年   472篇
  2003年   443篇
  2002年   376篇
  2001年   233篇
  2000年   195篇
  1999年   209篇
  1998年   119篇
  1997年   119篇
  1996年   124篇
  1995年   115篇
  1994年   111篇
  1993年   109篇
  1992年   168篇
  1991年   194篇
  1990年   171篇
  1989年   157篇
  1988年   148篇
  1987年   121篇
  1986年   128篇
  1985年   119篇
  1984年   123篇
  1983年   116篇
  1982年   77篇
  1981年   77篇
  1980年   84篇
  1979年   94篇
  1978年   81篇
  1977年   65篇
  1976年   82篇
  1975年   77篇
  1974年   86篇
  1973年   85篇
  1972年   65篇
排序方式: 共有9921条查询结果,搜索用时 312 毫秒
1.
2.
To test the reported antipanic efficacy of clonazepam, the authors randomized 72 subjects with panic disorder to 6 weeks of treatment with either alprazolam, clonazepam, or placebo. Endpoint analysis demonstrated a significant beneficial effect of both active treatments, but not placebo treatment, on the frequency of panic attacks, overall phobia ratings, and the extent of disability. Comparison of the two active treatments revealed no significant differences and no consistent tendency for one agent to be favored over another, although power to detect small differences was limited. Sedation and ataxia were the most common side effects reported, but these effects were mild and transient and did not interfere with treatment outcome. The results of this double-blind, placebo-controlled trial are consistent with previous reports of clonazepam's antipanic efficacy.  相似文献   
3.
Toxic effects of colloids in the intensive care unit.   总被引:4,自引:0,他引:4  
Colloid fluid solutions are frequently used as plasma volume expanders in the critically ill. As a group, these nonblood volume replacement solutions have in common a number of potential adverse effects. Intravascular volume overload, dilutional coagulopathy, extravascular extravasation across leaky capillary membranes, and anaphylactoid reactions may all occur with administration of any colloid. In addition, individual agents have unique toxic effects. Renal dysfunction has been associated with dextran 40, myocardial depression with albumin, hypotension with purified plasma protein, and hyperamylasemia with hetastarch. Because no ideal colloidal solution exists, knowledge of type, severity, and clinical significance of adverse effects is important in determining the appropriate plasma volume expander and monitoring its effects.  相似文献   
4.
Rats, initiated to self-administer 10% (v/v) ethanol in an operant situation using the sucrose-fading procedure, received bilateral n. accumbens microinjections of d-amphetamine prior to operant sessions. Doses of 4 micrograms, 10 micrograms and 20 micrograms/brain were administered and some animals also received a 4 microgram/brain dose of LY171555. Three different effects were observed: increased, decreased and no change in total session responding. There was no clear relation between injection area in the n. accumbens and type of effect observed. For either an increase or decrease in total session responding, momentary response rates were decreased. Both d-amphetamine and LY171555 produced similar results. The data support the hypothesis that dopamine in the n. accumbens is involved with ethanol reinforced operant responding but in a complex manner.  相似文献   
5.
6.
Somatostatin (SRIF) in the central nervous system is mostly concentrated in the median eminence (ME). Immunocytochemical methods have revealed high densities of SRIF-positive perikarya between the preoptic area and the periventricular nucleus of the hypothalamus (NPE). The aim of the present study was to define more precisely the specific pathways of SRIF neurons from NPE to the ME. SRIF levels were measured by radioimmunoassay, following various hypothalamic transections. Frontal periventricular sections decreased SRIF-ME content by 70% (P less than 0.01), when located at the anterior end of the ME but no diminution was observed when the cuts were located anteriorly or posteriorly. Parasaggital transections decreased SRIF-ME levels by 50% (P less than 0.05) when located at the outer border of the ventromedial and premammillary nucleus, but the decrease was not significant when cuts were located anteriorly. Taken together, our data indicate that most SRIF-containing neurons, originating in the NPE, do not reach the ME directly along the border of the 3rd ventricle; instead they form a loop across the medial forebrain bundle before re-entering the mediobasal hypothalamus at the ME level.  相似文献   
7.
8.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
9.
Alemtuzumab is a powerful lymphocyte depleting antibody currently being evaluated in solid organ transplantation. This paper describes 5-year results of a single center study of alemtuzumab as induction in renal transplantation. Thirty-three renal transplant recipients received 20 mg alemtuzumab on day 0 and 1, followed by half-dose cyclosporin monotherapy (trough concentration 75-125 ng/mL) from day 3. They were compared in a retrospective contemporaneous-controlled manner with 66 kidney transplant recipients transplanted in the same period and center who received conventional immunosuppression with cyclosporin, azathioprine and prednisolone. In the alemtuzumab group 12% of recipients died compared to 17% in the control group (p = 0.48); likewise graft loss was similar in both groups (21% vs. 26%, respectively, p = 0.58). Incidence of acute rejection was also comparable at 5 years (31.5% vs. 33.6%), although the pattern of rejection was different with 14% patients in the alemtuzumab group experiencing rejection over 1 year post-transplant compared to none in the control group. There was no significant difference between groups in terms of infection or serious adverse events. While acknowledging the limitations of a relatively small single-center study, results suggest that alemtuzumab induction allowed satisfactory long-term patient and graft survival equivalent to that seen with standard triple immunosuppression, while avoiding steroid therapy.  相似文献   
10.
The value of maternal C-reactive protein (CRP) levels as predictors of fetal and maternal infective morbidity and fetal mortality was assessed prospectively over a 6-month period in all cases of premature rupture of the fetal membranes or suspected premature labour. Statistical analysis of results showed that CRP at a level of 1.32 mg/dl is a sensitive marker of infective morbidity in mother and neonate. Furthermore, there was a significant association between raised CRP levels and low-birth-weight babies, suggesting that intra-uterine infection is a major cause of prematurity in the study population.  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