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   745篇
  免费   26篇
  国内免费   5篇
耳鼻咽喉   13篇
儿科学   11篇
妇产科学   46篇
基础医学   98篇
口腔科学   4篇
临床医学   51篇
内科学   235篇
皮肤病学   2篇
神经病学   44篇
特种医学   13篇
外科学   68篇
综合类   7篇
预防医学   39篇
眼科学   22篇
药学   84篇
中国医学   1篇
肿瘤学   38篇
  2022年   6篇
  2021年   11篇
  2020年   10篇
  2019年   16篇
  2018年   9篇
  2017年   13篇
  2016年   12篇
  2015年   17篇
  2014年   26篇
  2013年   37篇
  2012年   50篇
  2011年   61篇
  2010年   22篇
  2009年   14篇
  2008年   43篇
  2007年   55篇
  2006年   53篇
  2005年   38篇
  2004年   61篇
  2003年   44篇
  2002年   33篇
  2001年   15篇
  2000年   6篇
  1999年   3篇
  1995年   3篇
  1992年   4篇
  1991年   6篇
  1990年   7篇
  1989年   4篇
  1988年   4篇
  1987年   5篇
  1986年   6篇
  1985年   3篇
  1984年   3篇
  1983年   4篇
  1982年   5篇
  1981年   7篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   7篇
  1976年   3篇
  1975年   4篇
  1974年   4篇
  1973年   7篇
  1970年   2篇
  1969年   2篇
  1967年   3篇
  1965年   2篇
  1962年   1篇
排序方式: 共有776条查询结果,搜索用时 15 毫秒
1.
OBJECTIVES: The aim of the study was to check and present data on the relation between combined oral contraceptives (COC) use and body weight in young women living in Poland. METHODS: Observational study on the group of young women on COC and the control group of young women who never used COC. Candidates for study (145 women) and control (218 women) groups were recruited in selected gynecological clinics in Poland during the period of 1-31 January 2002 (with the use of randomization). RESULTS: Both groups (study and control) were almost identical in age, anthropometric characteristics, number of pregnancies and deliveries. On the basis of this investigation it was found that there was no relation between use of COC and weight gain. Observed (in both groups) weight gain in young women was most probably related rather to time-passing (patients were getting older). The higher risk for overweight and obesity was found in the group of young women who had already had problems with overweight in their childhood. and in the group of women with high weight gain during the first pregnancy. CONCLUSION: COC use is not associated with weight gain in young women with a Central European life-style.  相似文献   
2.
A number of more or less distinct entities with low birth weight and abnormal radiographic appearances have been identified. We studied two sisters who were unusual because of severe intrauterine growth restriction, absence of growth after birth, decrease of pre- and postnatal spontaneous mobility, and early fatal outcome. The chondro-osseous morphology documented a distinctive osteochondrodysplasia. The radiographic examination was superficially similar to gracile bone dysplasias but was inconsistent with any known types of this group. These two patients appear to have a unique gracile bone dysplasia.  相似文献   
3.
Despite magnesium (Mg2+) representing the second most abundant cation in the cell, its role in cellular physiology and pathology is far from being elucidated. Mg2+ homeostasis is regulated by Mg2+ transporters including Mitochondrial RNA Splicing Protein 2 (MRS2), Transient Receptor Potential Cation Channel Subfamily M, Member 6/7 (TRPM6/7), Magnesium Transporter 1 (MAGT1), Solute Carrier Family 41 Member 1 (SCL41A1), and Cyclin and CBS Domain Divalent Metal Cation Transport Mediator (CNNM) proteins. Recent data show that Mg2+ transporters may regulate several cancer cell hallmarks. In this review, we describe the expression of Mg2+ transporters in digestive cancers, the most common and deadliest malignancies worldwide. Moreover, Mg2+ transporters’ expression, correlation and impact on patient overall and disease-free survival is analyzed using Genotype Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) datasets. Finally, we discuss the role of these Mg2+ transporters in the regulation of cancer cell fates and oncogenic signaling pathways.  相似文献   
4.
Two versions of a multicomponent mind-body wellness intervention were tested. One hundred seventy-eight physician-referred HMO patients (mean age = 64.5) were randomly assigned to a classroom intervention, a home study intervention, or a wait-list control group. Both interventions provided instruction on mind-body relationships, relaxation training, cognitive restructuring, problem solving, communication, behavioral treatment for insomnia, nutrition, and exercise. The home version was delivered by class videotapes and readings. Compared with the control condition, both interventions led to significant decreases in self-reports of pain, sleep difficulties, and symptoms of depression and anxiety. The home course also led to a significant decrease in self-reported frequency of medical symptoms, and the classroom program resulted in a significant decrease in "chance" health locus of control beliefs. No effects were obtained for health behaviors, life satisfaction, HMO satisfaction, and other health locus of control beliefs. A lower cost, more accessible home study version of a mind-body wellness program can be an effective alternative to classroom instruction.  相似文献   
5.
A new and inexpensive system allowing rapid and synchronized changes of solutions around a membrane patch or a cell under voltage-clamp conditions is described. Four plastic capillary tubings (OD 640 m; ID 430 m) were glued together horizontally and attached to a coil of a commercially available loudspeaker. Servo-control of the position of the coil allowed the mouth of any of the capillaries to be positioned near the pipette tip within 6 ms. A high flow speed of the test solution was crucial to achieve rapid solution exchange. At a flow speed of 5 cm/s, complete exchange of the external environment of a frog ventricular cell was achieved within 20–30 ms. The time course of solution change was found to be 3–5 times faster at the tip of an open patch pipette. To preserve the physical integrity of the cell, the cell was usually perfused by a control capillary at a slow velocity (0.2 –0.4 cm/s) and test solutions flowing out of adjacent capillaries at high velocity (4–5 cm/s) were applied to the cell only for short periods. Determination of the three-dimensional contamination profile around the mouth of the control capillary allowed the optimal conditions for the use of the system to be established and possible sources of contamination to be avoided between adjacent capillaries with unmatched flow speeds. Successive and multiple changes in external solutions could be easily synchronized with voltage-clamp depolarizations to examine the time course of the effect of drugs on voltage-operated ion channels. An example of this application is given with rapid applications of the dihydropyridine agonist (-)BayK 8644 to the L-type Ca2+ channel current in frog ventricular myocytes.  相似文献   
6.
A large percentage of older adults must endure at least one chronic medical illness. Clinically significant depression and anxiety are common among these patients. Specific psychotherapy approaches as well as adaptations required to address the unique issues of this population have not been delineated in the literature. We outline a cognitive-behavioral therapy approach and discuss five treatment issues we have found to be important for this population. These issues include: (1) resolving practical barriers to participation; (2) accepting depression as a separate and reversible problem; (3) limiting excess disability; (4) counteracting the loss of important social roles and autonomy; and (5) challenging the perception of being a "burden." A case study of a chronic obstructive pulmonary disease (COPD) patient with depression is presented and recommendations for future research are suggested.  相似文献   
7.
The effects of FireMaster BP-6 and several pure isomers on hepatic microsomal mixed-function oxidase (MFO) activity in rainbow trout have been investigated. After one parenteral injection of these agents at 150 mg/kg and sacrifice 5 d later, there was no elevation of hepatic cytochrome P-450. The noncoplanar isomers 2,4,5,2',4',5'-hexa and 2,3,4,5,2',4',5'-heptabromobiphenyl did not increase any MFO activity generally associated with an increase in cytochrome P-450 levels, including the dealkylations of ethoxycoumarin and benzphetamine. The coplanar isomer 3,4,5,3',4',5'-hexabromobiphenyl produced an increase in O-deethylation of both ethoxycoumarin and ethoxyresorufin, suggesting enhancement of cytochrome P-448 associated activity, but produced no increase in benzphetamine N-dealkylation. The "mixed inducer" 2,4,5,3',4',5'-hexabromobiphenyl, produced a small but insignificant elevation of cytochrome P-448 associated MFO activities and no increase in cytochrome P-450 associated activities. At both 150 and 500 mg/kg, the commercial mixture of polybrominated biphenyls FireMaster BP-6 produced marked elevations of both ethoxycoumarin and ethoxy-resorufin dealkylations but had no effect on demethylation of benzphetamine. When microsomes from rainbow trout treated with FireMaster BP-6 were examined electrophoretically, A coomassie Blue-staining band at 57,000 daltons was intensified, as seen after treatment of fish with the cytochrome P-448 inducer beta-naphthoflavone. It is concluded that coplanar polybrominated isomers produce an induction of hepatic cytochrome P-448 associated activity, while noncoplanar isomers are ineffective as inducers of cytochrome P-450 related MFO activities in rainbow trout.  相似文献   
8.
9.
10.
BackgroundNeuropsychiatric complications of surgical coronary revascularization are inconspicuous but frequent and clinically relevant. So far, attempts to reduce their occurrence, such as the introduction of off-pump coronary artery bypass (OPCAB) grafting method, have not brought the desired results. The aim of this trial was to determine whether using any of the 2 selected modifications of OPCAB could decrease the incidence of these undesired sequelae.MethodsIn this single-center, assessor- and patient-blinded, superiority, randomized controlled trial, 192 patients scheduled for elective isolated OPCAB were randomized to 3 parallel arms. The control arm underwent “conventional” OPCAB with vein grafts. The first study arm underwent anaortic OPCAB (ANA) with total arterial revascularization. The second study arm underwent OPCAB with vein grafts using carbon dioxide surgical field flooding (CO2FF). Outcomes included the incidence of postoperative delirium (PD) and early postoperative cognitive dysfunction (ePOCD).ResultsThe incidence of PD was 35.9% in the control (OPCAB) arm, 32.8% in the CO2FF arm, and 12.5% in the ANA arm (χ2 [2, N = 191] = 10.17; P = .006). Post hoc tests revealed that the incidence of PD in the ANA arm differed from that in the OPCAB arm (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.09-0.68; P = .002). The incidence of ePOCD was 34.4% in the OPCAB arm, 28.1% in the CO2FF arm, and 9.5% in the ANA arm (χ2 [2, N = 191] = 11.58; P = .003). Post hoc tests revealed that the incidence of ePOCD differed between the ANA and OPCAB arms (OR, 0.20; 95% CI, 0.06-0.58; P < .001).ConclusionsPerforming ANA significantly decreases the incidence of PD and ePOCD compared with “conventional” OPCAB with vein grafts, whereas CO2FF is inconsequential in this regard. These results, which probably reflect decreased delivery of embolic load to the brain in ANA, may have practical applicability in daily practice to improve clinical outcomes.  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