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   4305篇
  免费   436篇
  国内免费   57篇
耳鼻咽喉   19篇
儿科学   196篇
妇产科学   90篇
基础医学   581篇
口腔科学   127篇
临床医学   567篇
内科学   779篇
皮肤病学   45篇
神经病学   309篇
特种医学   319篇
外国民族医学   1篇
外科学   484篇
综合类   116篇
一般理论   5篇
预防医学   490篇
眼科学   33篇
药学   276篇
中国医学   6篇
肿瘤学   355篇
  2021年   50篇
  2019年   47篇
  2018年   48篇
  2017年   51篇
  2016年   46篇
  2015年   88篇
  2014年   102篇
  2013年   213篇
  2012年   164篇
  2011年   179篇
  2010年   103篇
  2009年   96篇
  2008年   190篇
  2007年   178篇
  2006年   138篇
  2005年   132篇
  2004年   175篇
  2003年   152篇
  2002年   165篇
  2001年   159篇
  2000年   129篇
  1999年   134篇
  1998年   60篇
  1997年   74篇
  1996年   56篇
  1995年   62篇
  1994年   52篇
  1993年   49篇
  1992年   109篇
  1991年   88篇
  1990年   86篇
  1989年   95篇
  1988年   76篇
  1987年   83篇
  1986年   74篇
  1985年   88篇
  1984年   61篇
  1983年   54篇
  1982年   34篇
  1980年   37篇
  1979年   67篇
  1978年   35篇
  1976年   35篇
  1974年   43篇
  1973年   47篇
  1972年   49篇
  1971年   48篇
  1970年   36篇
  1969年   48篇
  1968年   42篇
排序方式: 共有4798条查询结果,搜索用时 15 毫秒
191.

Objective

To evaluate the effect of disease‐modifying antirheumatic drugs (DMARDs) on the likelihood of patients with rheumatoid arthritis (RA) developing septic arthritis (SA).

Methods

The United Kingdom General Practice Research Database (GPRD) was used to identify adults with RA, and age‐, sex‐, and practice‐matched control subjects. Subjects were studied between 1987 and 2002. The risk of developing SA (excluding infected joint replacements) for individuals with RA was calculated and the effect of DMARD use determined.

Results

A total of 136,977 subjects (34,250 patients with RA, 102,747 controls) were identified. SA was identified in 345 subjects, of which 321 (236 in patients with RA, 85 in controls) cases occurred during the study period. The incidence rate of SA was 12.9 times higher in subjects with RA than in those without (95% confidence interval [95% CI] 10.1–16.5, P < 0.001). The incident rate ratios (IRRs) for developing SA while receiving DMARDs compared with receiving no DMARDs were different for different medications. Penicillamine (adjusted IRR 2.51, 95% CI 1.29–4.89, P = 0.004), sulfasalazine (adjusted IRR 1.74, 95% CI 1.04–2.91, P = 0.03), and prednisolone (adjusted IRR 2.94, 95% CI 1.93–4.46, P < 0.001) were associated with an increased incidence of SA when compared with not receiving any DMARD. The use of other DMARDs including methotrexate showed no such effect.

Conclusion

Individuals with RA have an increased risk of developing SA. This increased risk can be attributed to both the disease process and the use of DMARDs.  相似文献   
192.
STUDY OBJECTIVE: There is little evidence that cardiopulmonary resuscitation (CPR) alone may lead to the resuscitation of cardiac arrest victims with other than respiratory causes (eg, pediatric arrest, drowning, drug overdose). The objective of this study was to identify out-of-hospital cardiac arrest survivors resuscitated without defibrillation or advanced cardiac life support. METHODS: This observational cohort included all adult survivors of out-of-hospital cardiac arrest of a cardiac cause from phases I and II of the Ontario Prehospital Advanced Life Support Study. During the study period, the system provided a basic life support/defibrillation level of care but no advanced life support. CPR-only patients were patients determined to be without vital signs by EMS personnel who regained a palpable pulse in the field with precordial thump or CPR only and then were admitted alive to the hospital. Six members of a 7-member expert review panel had to rate the patient as either probably or definitely having an out-of-hospital cardiac arrest, and a rhythm strip consistent with a cardiac arrest rhythm had to be present to be considered a patient. Criteria considered were witness status, citizen or first responder CPR, CPR duration, arrest rhythm and rate, and performance of precordial thump. RESULTS: From January 1, 1991, to June 30, 1997, 9,667 patients with out-of-hospital cardiac arrest were treated. The overall survival rate to hospital discharge was 4.6%. There were 97 apparent CPR-only patients admitted to the hospital. Application of the inclusion criteria yielded 24 CPR-only patients who had true out-of-hospital cardiac arrest and 73 patients judged not to have cardiac arrest. Of the 24 true CPR-only patients admitted to the hospital, 15 patients were discharged alive, 10 patients were witnessed by bystanders, and 7 patients were witnessed by EMS personnel. The initial arrest rhythm was pulseless electrical activity in 9 patients, asystole in 12 patients, and ventricular tachycardia in 3 patients. One patient with ventricular tachycardia converted to sinus tachycardia with a single precordial thump. CONCLUSION: CPR-only survivors of true out-of-hospital cardiac arrest do exist; some victims of out-of-hospital cardiac arrest of primary cardiac cause can survive after provision of out-of-hospital basic life support care only. However, many patients found to be pulseless by means of out-of-hospital evaluation likely did not have a true cardiac arrest. This has implications for the survival rates of most, if not all, previous cardiac arrest reports. Survival rates from cardiac arrest may actually be lower if one excludes survivors who never had a true arrest. The absence of vital signs by out-of-hospital assessment alone is not adequate to include patients in research reports or quality evaluations for cardiac arrest.  相似文献   
193.
Transplants from partially human leukocyte antigens (HLA)-incompatible relatives are associated with an increased risk of graft rejection, graft-versus-host disease (GVHD), and lower survival, which are correlated with the degree of disparity. For patients without an HLA-matched sibling, the preferred donors of hematopoietic cells remain HLA-compatible, unrelated volunteers. The hurdle for a wider application of hematopoietic cell transplantation is the enormous polymorphism of HLA genes that makes unrelated individuals unlikely to match randomly. The identification of functional HLA genes and their polymorphic alleles, the development of precise and effective tissue typing techniques, and the assembly of large volunteer registries worldwide that exceed 9 million HLA-typed individuals have made it feasible to transplant hematopoietic stem cells from well-matched, unrelated donors for most patients.  相似文献   
194.
Role of plasmapheresis in primary biliary cirrhosis.   总被引:5,自引:0,他引:5       下载免费PDF全文
L B Cohen  E P Ambinder  A M Wolke  S P Field    F Schaffner 《Gut》1985,26(3):291-294
Five patients with primary biliary cirrhosis and prolonged cholestasis underwent intensive plasmapheresis. The indications for plasmapheresis included intractable pruritus or hypercholesterolemia and xanthomatous neuropathy. Patients noted a rapid improvement of pruritus and fatigue which was sustained as long as plasmapheresis was continued. Cholesterol levels were lowered an average of 10.3 mmol/l and xanthomata were reduced in three of four patients. Two patients with painful neuropathy caused by xanthomata experienced relief of this symptom. The liver and spleen size were not affected by plasmapheresis, and activities of aminotransferases, alkaline phosphatase and titres of mitochondrial antibody remained unchanged. We conclude that plasmapheresis has a role in the therapeutic management of patients with advanced primary biliary cirrhosis who are disabled by the complications of pruritus, xanthomatous neuropathy, or hypercholesterolemia with xanthoma formation.  相似文献   
195.
196.
197.
198.

BACKGROUND

Young adults are less likely than older adults to be aware they have hypertension or to be treated for hypertension.

OBJECTIVE

To describe rates of hypertension awareness and control in a cohort of young adults and understand the impact of health insurance, utilization of preventive care, and self-perception of health on rates of hypertension awareness and control in this age group.

DESIGN AND PARTICIPANTS

Cross-sectional study of 13,512 young adults participating in Wave IV of the National Longitudinal Study of Adolescent Health in 2007–2008.

MAIN MEASURES

We defined hypertension as an average of two measured systolic blood pressures (SBP) ≥ 140 mmHg, diastolic blood pressures (DBP) ≥ 90 mmHg, or self-report of hypertension. We defined hypertension awareness as reporting having been told by a health care provider that one had high blood pressure, and assessed awareness among those with uncontrolled hypertension. We considered those aware of having hypertension controlled if their average measured SBP was < 140 mmHg and DBP was < 90 mmHg.

KEY RESULTS

Of the 3,303 young adults with hypertension, 2,531 (76 %) were uncontrolled, and 1,893 (75 %) of those with uncontrolled hypertension were unaware they had hypertension. After adjustment for age, sex, race/ethnicity, weight status, income, education, alcohol and tobacco use, young adults with uncontrolled hypertension who had (vs. didn’t have) routine preventive care in the past 2 years were 2.4 times more likely (95 % confidence interval [CI] 1.68–3.55) to be aware, but young adults who believed they were in excellent (vs. less than excellent) health were 64 % less likely to be aware they had hypertension (OR 0.36, 95 % CI 0.23–0.57). Neither preventive care utilization nor self-rated health was associated with blood pressure control.

CONCLUSIONS

In this nationally representative group of young adults, rates of hypertension awareness and control were low. Efforts to increase detection of hypertension must address young adults’ access to preventive care and perception of their need for care.  相似文献   
199.
Femoroacetabular impingement (FAI) is a pathomechanical process by which the human hip can fail. The effect of attenuated cartilage on the kinematics and the pathological bone-to-bone contact of an osteoarthritic hip joint with FAI are still unknown. The current study is aiming to simulate osteoarthritis of a cam-type femoral head with cartilage thinning of varying severity. A three-dimensional model of the left hip joint of a male patient diagnosed with FAI was obtained from preoperative computerised tomography data using density segmentation techniques. The kinematics of FAI was simulated using a finite element method. As the acetabulum and femur came into contact, the penetrations were detected, and the contact constraints were applied according to the penalty constraint enforcement method. The translation and rotation parameters were defined in a single step for each one of three cases: healthy cartilage and 2 mm (one-sided thinning) and 4 mm (two-sided thinning) worn out articular cartilages. The results of the analysis show that thinning of the cartilage at the hip joint adversely affects impingement, as a range of motion decreased with progressive thinning of the articular cartilage. In the presence of attenuated cartilage, equating osteoarthritis, the pathomorphology of the cam lesion, likely determines the extent of damage on the rim of the acetabulum, as well.  相似文献   
200.
This study addressed the validity of the prolonged grief (PG) construct in a Cambodian context. Eighty mothers who lost a young adult daughter stemming from a crowd stampede incident during the annual water festival were interviewed at the six-month post-loss point along with a control group of similarly aged women who were not recently bereaved. Both groups were assessed for PG, PTSD, anxiety, and depression symptoms and well as for the number of distal losses experienced during the Khmer Rouge (KR) regime – knowing that all the women were old enough to have lived through the KR regime. Support for the discriminant validity of PG was shown in a factor analysis in which its core symptoms were distinguished from anxiety, depression, and PTSD symptoms. Also, support was found for its incremental validity as shown in the unique sensitivity of PG in distinguishing the two groups when controlling for the other symptoms. Lastly, a positive relationship was found between the number of distal deaths experienced during the KR regime and PG symptom severity among the group of recently bereaved mothers, providing support for the predictive validity of PG. Implications as well as study limitations are discussed.  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