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   3716篇
  免费   178篇
  国内免费   2篇
耳鼻咽喉   48篇
儿科学   100篇
妇产科学   174篇
基础医学   428篇
口腔科学   56篇
临床医学   335篇
内科学   624篇
皮肤病学   35篇
神经病学   559篇
特种医学   256篇
外科学   526篇
综合类   23篇
一般理论   4篇
预防医学   284篇
眼科学   61篇
药学   197篇
中国医学   3篇
肿瘤学   183篇
  2023年   16篇
  2022年   29篇
  2021年   75篇
  2020年   27篇
  2019年   69篇
  2018年   68篇
  2017年   53篇
  2016年   59篇
  2015年   87篇
  2014年   125篇
  2013年   147篇
  2012年   216篇
  2011年   235篇
  2010年   121篇
  2009年   127篇
  2008年   202篇
  2007年   181篇
  2006年   189篇
  2005年   179篇
  2004年   177篇
  2003年   141篇
  2002年   138篇
  2001年   105篇
  2000年   87篇
  1999年   81篇
  1998年   30篇
  1997年   37篇
  1996年   25篇
  1995年   17篇
  1994年   28篇
  1993年   25篇
  1992年   65篇
  1991年   47篇
  1990年   48篇
  1989年   56篇
  1988年   54篇
  1987年   38篇
  1986年   35篇
  1985年   29篇
  1984年   26篇
  1983年   14篇
  1979年   19篇
  1977年   22篇
  1976年   16篇
  1975年   21篇
  1974年   24篇
  1973年   16篇
  1972年   17篇
  1971年   23篇
  1970年   16篇
排序方式: 共有3896条查询结果,搜索用时 46 毫秒
1.
Summary Based upon the hypothesis that dipyridamole would potentiate the cytotoxicity of mitoxantrone and the combination of 5-fluorouracil (5-FU) and leukovorin, we performed a phase I/II trial of the combination of dipyridamole, 5-FU, leukovorin, and mitoxantrone in patients with metastatic breast cancer. The dose of dipyridamole was fixed at 175 mg/m2 by mouth every 6 h (700 mg/m2/day), based upon a previous phase I trial of oral dipyridamole with 5-FU and leukovorin. Dipyridamole therapy began 24 h prior to the first dose of chemotherapy and continued until 24 h after the last dose of chemotherapy for each course of treatment. At the initial dose level, leukovorin 200 mg/m2 was given intravenously immediately prior to 5-FU 375 mg/ m2 intravenously on days 1–5. Mitoxantrone 6 mg/m2 was given as a single dose on day 3. Unacceptable toxicity was observed at this dose level, leading to successive dose decrements rather than dose increments. The maximum tolerated dose was leukovorin 200 mg/m2 days 1–2, 5-FU 375 mg/m2 days 1–2, mitoxantrone 6 mg/m2 on day 2, and dipyridamole 175 mg/m2 every 6 h on days 0–3. Two responses were produced in 15 patients. This regimen is not recommended for further investigation in the treatment of breast cancer.  相似文献   
2.
Age, socioeconomic status, and health   总被引:29,自引:0,他引:29  
Analysts dispute what roles biomedical, psychosocial, and other factors play in determining the duration of morbidity and disability over the life course. Cross-sectional data from two national surveys of adults aged 25 years and over not only show, however, that age and socioeconomic status (SES) are significant predictors of self-reported physical health; they also demonstrate that the relation of age to health varies with SES features. Longitudinal research is needed to test the finding that enduring functional limitations in terms of time are actually compressed in higher SES groups. To improve well-being in our society, moreover, requires specifying why SES differences occur, and perhaps ultimately reducing socioeconomic inequality itself.  相似文献   
3.
4.
Andrew G. Herzog  MD  MSc 《Headache》2007,47(S2):S68-S78
Migraine is 3 times more common in postpubertal women than in men. Migraine is frequently exacerbated perimenstrually and commonly occurs exclusively at that time. It is often benefited by pregnancy and menopause. Estrogen withdrawal has been implicated as a mechanism for triggering migraines. The mechanism, however, is not well understood. Reproductive steroids have neuroactive properties that can modulate neuronal morphology and physiology. Increasing evidence suggests that circulating reproductive steroid levels regulate the balance of neuroexcitatory and neuroinhibitory activities in some brain regions by influencing synaptic plasticity. Estrogen has neuroexcitatory, whereas progesterone has neuroinhibitory, effects in most preclinical and clinical models. Several neurotransmitter systems that are implicated in migraine vary with reproductive steroid levels during the reproductive cycle. Estrogen stabilization may provide effective treatment in susceptible women, especially for catamenially exacerbated migraine.  相似文献   
5.
6.
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy for Parkinson's disease (PD). A manic episode with psychotic symptoms induced by STN-DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN-DBS in influencing not only motor but also emotional behaviour.  相似文献   
7.
H A Schut  C R Herzog 《Cancer letters》1992,67(2-3):117-124
2-Amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP) is known to induce colon tumors in male Fischer-344 rats. Using 32P-postlabeling assays, we have examined PhIP-DNA adduct formation in various organs and white blood cells (WBCs) of the male Fischer-344 rat 24 h after a single oral dose of 0, 0.5, 5 or 50 mg PhIP/kg. Three PhIP-DNA adducts were detected in WBCs and in all organs, except in the liver and stomach which had only two adducts. The extent of adduct formation was dose-related, but at 0.5 mg/kg no adducts could be detected in any of the organs. At 50 mg/kg, adduct levels, expressed as relative adduct labeling values (RAL x 10(7), or adducts per 10(7) nucleotides assuming complete labeling) were highest in the large intestine (5.66), followed by WBCs (5.04), stomach (1.44), small intestine (1.32), kidney (1.16), liver (0.67) and lungs (0.52). It is concluded that orally administered PhIP forms high levels of specific DNA adducts in the large intestine, the target organ in PhIP carcinogenesis in the male Fischer-344 rat, and that the high level of adducts in WBCs indicates that significant amounts of the ultimate carcinogenic form of PhIP are present in the circulation.  相似文献   
8.
The establishment of the ABO chimerism (two populations of erythrocytes deviating in ABO antigens) following a bone marrow transplantation represents a simple rapid method for the proof of the transplant acceptance. A remarkable case was described in which in a patient with hypoplasia of the bone marrow in the peripheral blood there exist two deviating in ABO antigens populations of erythrocytes (AB blood corpuscles of the patient and B erythrocytes of the donor) still 4 1/2 years after the transplantation of the bone marrow. This fact speaks for the simultaneous existence of the own bone marrow as well as of the bone marrow of the donor in the patient.  相似文献   
9.
We studied the influence of human prolactin on the secretion and de novo synthesis of human chorionic gonadotropin (hCG) in the human term placenta in culture. Placental tissue from 14 patients with uncomplicated pregnancies and deliveries was prepared mechanically, with addition of a Percoll gradient step. hCG levels were determined in the culture media and in the cytosolic fraction of cells by means of an enzyme immunoassay with coated beads. The amount of newly synthesized hCG was measured by the extent of incorporation of 35S-methionine into the hCG molecule. Our results showed that human prolactin had two different effects in vitro: between 1/2 and 1 h, prolactin slightly increased secretion of hCG into the culture medium without affecting de novo synthesis; after 2 h, prolactin began to cause a significant decrease in both secretion and de novo synthesis of hCG over several hours. It appears that both effects are receptor mediated, for ovine prolactin failed to produce any response. We conclude that prolactin is one of the main factors regulating the synthesis and secretion of hCG in the human trophoblast at term.  相似文献   
10.
Ethical issues in child and adolescent psychiatry consultation arise frequently but seldom are discussed in a public setting. This case of an adolescent victim of a surgical accident illustrates many aspects of consultation psychiatry. The consult question itself, of behavior management, is not unusual, although in this case the question is complicated by the sequelae of trauma, psychosocial chaos, and the staff's angry feelings toward the patient. In addition, potential surgical wrongdoing at the referring hospital brings up the more difficult ethical questions of the consultant's responsibilities, which must be to the patient and his family, as well as to the attending and referring physicians.  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