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   11439篇
  免费   1266篇
  国内免费   21篇
耳鼻咽喉   64篇
儿科学   301篇
妇产科学   375篇
基础医学   1557篇
口腔科学   202篇
临床医学   1280篇
内科学   2653篇
皮肤病学   165篇
神经病学   1314篇
特种医学   555篇
外科学   1240篇
综合类   231篇
一般理论   11篇
预防医学   1155篇
眼科学   161篇
药学   703篇
中国医学   6篇
肿瘤学   753篇
  2021年   123篇
  2020年   113篇
  2019年   150篇
  2018年   173篇
  2017年   151篇
  2016年   185篇
  2015年   244篇
  2014年   284篇
  2013年   383篇
  2012年   535篇
  2011年   525篇
  2010年   323篇
  2009年   302篇
  2008年   565篇
  2007年   514篇
  2006年   477篇
  2005年   493篇
  2004年   403篇
  2003年   359篇
  2002年   315篇
  2001年   317篇
  2000年   373篇
  1999年   315篇
  1998年   155篇
  1997年   164篇
  1996年   166篇
  1995年   128篇
  1994年   109篇
  1993年   109篇
  1992年   253篇
  1991年   276篇
  1990年   251篇
  1989年   250篇
  1988年   213篇
  1987年   228篇
  1986年   249篇
  1985年   228篇
  1984年   170篇
  1983年   154篇
  1982年   112篇
  1981年   93篇
  1980年   97篇
  1979年   170篇
  1978年   105篇
  1977年   93篇
  1975年   94篇
  1974年   101篇
  1973年   102篇
  1972年   94篇
  1971年   92篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
AIMS: To show that a thrice daily meal-time biphasic insulin aspart (BIAsp) treatment regimen is as efficacious as a 4 times daily basal-bolus regimen with human isophane insulin (NPH) and insulin aspart (IAsp). METHODS: A multinational, randomised, open-label parallel-group trial in 394 patients with type 2 diabetes on a once or twice daily insulin regimen. Patients were randomised 1:1 to BIAsp or IAsp+NPH for 16 weeks. The BIAsp group was treated according to individual needs using BMI as a surrogate index of insulin resistance. Subjects administered BIAsp 70 (BMI< or =30 kg/m (2)) or BIAsp 50 (BMI>30 kg/m (2)) with breakfast and lunch and BIAsp 30 with dinner. The IAsp+NPH group injected IAsp at meals and NPH at bedtime as basal insulin. HbAlc levels after 16 weeks were compared between treatments using a predefined non-inferiority criterion of 0.4%. The incidence of hypoglycaemic episodes and adverse events was evaluated. RESULTS: Mean HbAlc (+/-SD) decreased from 9.1+/-0.7% to 7.8+/-1.0% with both treatments. Glycaemic control provided by BIAsp was non-inferior to that obtained by the IAsp+NPH (intention to treat ITT) population: diff, HbAlc -0.05%; 95% CI (-0.24; 0.14); per protocol (PP) population: diff, HbAlc -0.03%; 95% CI (-0.23; 0.16). Similar improvements in glycaemic control in both groups were confirmed by self-measured 8-point plasma glucose (PG) profiles, average and fasting PG concentrations, and average prandial PG increments. The incidence of adverse events and hypoglycaemic episodes was similar in the two treatment groups. CONCLUSIONS: A thrice daily meal-time BIAsp regimen is a suitable alternative to an intensified insulin regimen in people with inadequately controlled type 2 diabetes mellitus, and requires fewer daily injections than a basal-bolus therapy without compromising efficacy and safety.  相似文献   
22.
23.
H Fox 《Midwifery》1991,7(1):31-39
Our current knowledge of the human placenta is briefly reviewed. Particular stress is placed upon the considerable functional reserve capacity of the placenta, the unimportance of most visible abnormalities of the placenta, the lack of any evidence that the placenta ages during gestation and the lack of significance of placental weight. The effects on the placenta of infection and of maternal cigarette smoking are considered and the concept of placental insufficiency critically discussed. It is concluded that most cases of 'placental insufficiency' are, in reality, examples of maternal vascular insufficiency resulting from inadequate placentation during the early stages of pregnancy.  相似文献   
24.
Effect of Medicaid payment levels on access to obstetrical care.   总被引:3,自引:0,他引:3  
Across the nation, the number of providers serving pregnant Medicaid clients has dropped precipitously. In an effort to retain providers, in 1986 the Maryland Medicaid program tripled reimbursement fees for deliveries. This raised Medicaid payments for perinatal care to levels roughly comparable to those paid by private insurers. Providers' participation can be measured using two criteria: the total number of participating providers in a given country and the number of deliveries performed by targeted providers. The fee increase was associated with an overall stabilization in the number of providers performing deliveries. Providers performed slightly more deliveries after the fee increase, relative to predictions derived from statistical models. One-quarter of all providers increased their participation on a scale commensurate with the fee increase.  相似文献   
25.
26.
27.
28.
We describe the pattern and progression of atrophy delineated using fluid registration of serial magnetic resonance imaging scans in a case of multiple system atrophy (MSA). The in vivo findings were consistent with those found at postmortem, including significant supratentorial atrophy concurrent with an unusual degree of cognitive impairment for MSA.  相似文献   
29.
The anterior cruciate ligament has a complex fiber anatomy and is not considered to be a uniform structure. Current anterior cruciate ligament reconstructions succeed in stabilizing the knee, but they neither fully restore normal knee kinematics nor reproduce normal ligament, function. To improve the outcome of the reconstruction, it may be necessary to reproduce the complex function of the intact anterior cruciate ligament in the replacement graft. We examined the in situ forces in nine human anterior cruciate ligaments as well as the force distribution between the anteromedial and posterolateral bundles of the ligament in response to applied anterioi tibial loads ranging from 22 to 110 N at knee flexion angles of 0–90°. The analysis was performed using a robotic manipulator in conjunction with a universal force-moment sensor. The in situ forces were determined with no device attached to the ligament, while the knee was permitted to move freely in response to the applied loads. We found that the in situ forces in the anterior cruciate ligament ranged from 12.8 ± 7.3 N under 22 N of anterior tibial load applied at 90° of knee flexion to 110.6 ± 14.8 N under 110 N of applied load at 15° of flexion. The magnitude of the in situ force in the posterolateral bundle was larger than that in the anteromedial bundle at knee flexion angles between 0 and 45°, reaching a maximum of 75.2 ± 18.3 N at 15° of knee flexion under an anterior tibial load of 110 N. The magnitude of the in situ force in the posterolateral bundle was significantly affected by knee flexion angle and anterior tibial load in a fashion remarkably similar to that seen in the anterior cruciate ligament. The magnitude of the in situ force in the anteromedial bundle, in contrast, remained relatively constant, not changing with flexion angle. Significant differences in the direction of the in situ force between the anteromedial bundle and the posterolateral bundle were found only at flexion angles of 0 and 60° and only under applied anterior tibial loads greater than 66 N. We have demonstrated the nonuniformity of the anterior cruciate ligament under unconstrained anterior tibial loads. Our data further suggest that in order for the anterior cruciate ligament replacement graft to reproduce the in situ forces of the normal anterior cruciate ligament, reconstruction techniques should take into account the role of the posterolateral bundle in addition to that of the anteromedial bundle.  相似文献   
30.
The organization of daily procedures within the operating theatre is considered in terms of rival perspectives on their patient held by surgeon and anaesthetist. The privileging of the surgeon's authority is challenged in anaesthetists' efforts to fabricate a distinctive position on the patient. While surgeons focus on patient as the carrier of disease, for the anaesthetist, the focus is upon the patient's complement of fitness. A postmodern analysis of the organization of surgery reflects the continual struggle between the two specialisms to privilege its particular definition of the surgical patient. In some circumstances, the struggle can have damaging consequences for patient care.  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