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   19241篇
  免费   1460篇
  国内免费   197篇
耳鼻咽喉   176篇
儿科学   697篇
妇产科学   407篇
基础医学   1768篇
口腔科学   342篇
临床医学   2715篇
内科学   3827篇
皮肤病学   255篇
神经病学   1661篇
特种医学   723篇
外科学   3519篇
综合类   351篇
一般理论   18篇
预防医学   1648篇
眼科学   685篇
药学   1075篇
中国医学   10篇
肿瘤学   1021篇
  2023年   181篇
  2022年   175篇
  2021年   303篇
  2020年   251篇
  2019年   298篇
  2018年   422篇
  2017年   386篇
  2016年   418篇
  2015年   417篇
  2014年   584篇
  2013年   805篇
  2012年   876篇
  2011年   888篇
  2010年   649篇
  2009年   691篇
  2008年   801篇
  2007年   759篇
  2006年   789篇
  2005年   718篇
  2004年   711篇
  2003年   603篇
  2002年   621篇
  2001年   458篇
  2000年   406篇
  1999年   438篇
  1998年   335篇
  1997年   332篇
  1996年   434篇
  1995年   349篇
  1994年   312篇
  1993年   243篇
  1992年   402篇
  1991年   376篇
  1990年   268篇
  1989年   322篇
  1988年   285篇
  1987年   259篇
  1986年   271篇
  1985年   235篇
  1984年   206篇
  1983年   171篇
  1982年   145篇
  1981年   141篇
  1980年   170篇
  1979年   124篇
  1978年   139篇
  1977年   118篇
  1976年   128篇
  1973年   125篇
  1972年   122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.

Background

Intense postoperative monitoring has resulted in increasing detection of patients with recurrent papillary thyroid cancer (PTC). Our goals included quantifying successful reoperation, and analyzing surgical complications and reasons for relapse.

Methods

From 1999 to 2008, a total of 410 patients underwent reoperation for PTC relapse. We analyzed post-reoperative disease outcomes, reasons for relapse, and complications.

Results

Bilateral reoperative thyroidectomy was performed in 13 (3 %) patients; lobectomy, 34 (8 %); central neck (VI) soft tissue local recurrence excision, 47 (11.5 %); bilateral VI node dissection, 107 (26 %); unilateral VI dissection, 112 (27 %); levels II–V dissection, 93 (23 %); levels III–V, 86 (21 %); lateral single- or two-compartment dissection, 51 (12 %); and node picking, 20 (5 %) of level VI and 53 (13 %) lateral neck. Complications occurred in 6 %; including hypoparathyroidism, 3 %; unintentional recurrent laryngeal nerve (RLN) paralysis, 3 %; phrenic nerve injury, 0.5 %; spinal accessory nerve injury, 0.5 %; and chyle leak in 1.6 %. Of 380 (93 %) patients with follow-up (mean 5.2 years); 274 (72 %) patients are alive with no structural evidence of disease, 38 % developed disease relapse (mean 2.1 years), 42 (11 %) died from PTC, and 55 (14 %) are alive with disease. The reason for relapse was a false negative pre-reoperative ultrasound (US) in 18 (5 %), nodal recurrence in the operative field in 37 (10 %), a combination of these two reasons in 10 (3 %), and disease virulence (local or systemic recurrence) in 81 (21 %).

Conclusions

Although 72 % of patients were rendered structurally disease free after reoperation, nearly 40 % suffered additional relapse. Improved surgical technique or preoperative localization might positively affect 15–20 %; at least 20 % reflect the biologic aggressiveness of the disease.  相似文献   
33.
Futility has been a contentious topic in medicine for several decades. Surgery in critical or end-of-life situations often raises difficult questions about futility. In this article, we discuss the definition of futility, methods for resolving futility disputes, and some ways to reframe the futility debate to a more fruitful discussion about the goals of care, better communication between surgeon and patient/surrogate, and palliative surgical care. Many definitions of futile therapy have been discussed. The most controversial of these is “qualitative futility” which describes a situation in which the treatment provided is likely to result in an unacceptable quality of life. This is an area of continued controversy because it has been impossible to identify universally held beliefs about acceptable quality of life. Many authors have described methods for resolving futility disputes, including community standards and legalistic multi-step due process protocols. Others, however, have abandoned the concept of futility altogether as an unhelpful term. Reframing the issue of futility as one of inadequate physician–patient communication, these authors have advocated for methods of improving communication and strengthening the patient–physician relationship. Finally, we discuss the utilization of consultants who may be of use in resolving futility disputes: ethics committees, palliative care specialists, pastoral care teams, and dedicated patient advocates. Involving these specialists in a futility conflict can help improve communication and provide invaluable assistance in arriving at the appropriate treatment decision.  相似文献   
34.
Microsomal prostaglandin E synthase-1 (mPGES-1) in myeloid and vascular cells differentially regulates the response to vascular injury, reflecting distinct effects of mPGES-1–derived PGE2 in these cell types on discrete cellular components of the vasculature. The cell selective roles of mPGES-1 in atherogenesis are unknown. Mice lacking mPGES-1 conditionally in myeloid cells (Mac-mPGES-1-KOs), vascular smooth muscle cells (VSMC-mPGES-1-KOs), or endothelial cells (EC-mPGES-1-KOs) were crossed into hyperlipidemic low-density lipoprotein receptor-deficient animals. En face aortic lesion analysis revealed markedly reduced atherogenesis in Mac-mPGES-1-KOs, which was concomitant with a reduction in oxidative stress, reflective of reduced macrophage infiltration, less lesional expression of inducible nitric oxide synthase (iNOS), and lower aortic expression of NADPH oxidases and proinflammatory cytokines. Reduced oxidative stress was reflected systemically by a decline in urinary 8,12-iso-iPF-VI. In contrast to exaggeration of the response to vascular injury, deletion of mPGES-1 in VSMCs, ECs, or both had no detectable phenotypic impact on atherogenesis. Macrophage foam cell formation and cholesterol efflux, together with plasma cholesterol and triglycerides, were unchanged as a function of genotype. In conclusion, myeloid cell mPGES-1 promotes atherogenesis in hyperlipidemic mice, coincident with iNOS-mediated oxidative stress. By contrast, mPGES-1 in vascular cells does not detectably influence atherogenesis in mice. This strengthens the therapeutic rationale for targeting macrophage mPGES-1 in inflammatory cardiovascular diseases.Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce pain and inflammation by suppressing the formation of proinflammatory prostaglandins (PGs), particularly prostaglandin E2 (PGE2) formed by cyclooxygenase-2 (COX-2) (1). However, the development of NSAIDs specific for inhibition of COX-2 revealed a cardiovascular hazard attributable to suppression of cardioprotective PGs, especially prostacyclin (PGI2) (2). This risk appears to extend to some of the older NSAIDs, like diclofenac, that also inhibit specifically COX-2 (3, 4). These developments prompted interest in microsomal PGE synthase (mPGES)-1 as a downstream alternative drug target to COX-2 (5): it is the dominant source among PGES enzymes in the biosynthesis of PGE2 (6). Unlike NSAIDs, inhibitors of mPGES-1 would spare PGI2 from suppression. Indeed, blockade or deletion of mPGES-1 results in accumulation of its PGH2 substrate, rendering it available for metabolism by other PG synthases, including PGI2 synthase (PGIS) (7).Consistent with these observations, we have found that whereas deletion of COX-2 in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) renders mice susceptible to thrombosis and hypertension (2), deletion of mPGES-1 in vascular cells has no such effect (8). Indeed, global deficiency of mPGES-1 restrains atherogenesis (9), the proliferative response to vascular injury (10) and angiotensin-induced aortic aneurysm formation (11) in mice.Despite this attractive cardiovascular profile, mPGES-1 is a complex drug target. The dominant prostanoid products of substrate rediversion differ among cell types. For example, whereas PGI2 might be augmented in vascular cells, the consequence of mPGES-1 blockade in other cells might be an increase in thromboxane (Tx)A2, a PG that promotes platelet activation, vasoconstriction, and atherogenesis (9). Even if an increase in PGI2 afforded a desirable cardiovascular profile, it might undermine the analgesic efficacy of mPGES-1 inhibitors. Although the impacts of global deletion of mPGES-1 and COX-2 in many mouse models of analgesia are indistinguishable (12, 13), in some, PGI2 rather than PGE2 predominates (14) and thus may be the dominant mediator in certain subtypes of human pain. Finally, the consequences of PGE2 suppression might differ between cell types. PGE2 activates four E prostanoid (EP) receptors with contrasting intracellular signaling and consequent biology (15, 16). Indeed, the contrasting effect of mPGES-1 deletion in myeloid vs. vascular cells on the proliferative response to vascular injury reflects the differential consequences of EP activation rather than substrate rediversion (8).A potentially discriminating feature among inhibitors of COX-2 and mPGES-1 is their effect on atherosclerosis. Global postnatal deletion of COX-2 accelerates atherogenesis in hyperlipidemic mice (17), an observation that accords with a similar effect of deleting the PGI2 receptor (the IP) (18, 19) and with the delayed detection of a cardiovascular hazard in randomized trials of COX-2 inhibitors in patients initially selected for being at low cardiovascular risk (20). By contrast, global deletion of mPGES-1 restrains atherogenesis in mice; in this case suppression of PGE2 coincides with an increase in biosynthesis of PGI2 (9). Here, we wished to segregate the effects on atherosclerosis of mPGES-1 depletion in myeloid from vascular cells. Our results strengthen the rationale for targeting macrophage mPGES-1 in the treatment of inflammatory cardiovascular disease.  相似文献   
35.

Purpose

This is a selective narrative review of the latest information about the epidemiology, impact, and prevention of chronic post-surgical pain (CPSP), intended primarily for those without a special interest in pain medicine.

Principal findings

Chronic post-surgical pain is an important problem in terms of personal impact. It has staggering economic implications, exerts powerful negative effects on the quality of life of many of those it afflicts, and places a significant burden on chronic pain treatment services in general. It is well known that surgery at certain body sites is apt to cause CPSP, but emerging evidence shows a strong correlation between CPSP and demographic (young age, obesity, and female sex) and psychological characteristics (anxiety, depression, stress, and catastrophizing). Severe acute pain is a strong risk factor for CPSP, and this adds yet more weight to the argument that acute pain should be controlled effectively. In specific circumstances, CPSP can be reduced by regional anesthetic techniques, infiltration of local anesthetic, or preoperative use of gabapentin. The ability of other known interrupters of afferent nociceptive transmission—commonly used to reduce CPSP when administered at the time of surgery—is currently unproven, as is the hypothesis that the use of remifentanil during surgery worsens CPSP.

Conclusions

Reduction of CPSP is a worthy long-term outcome for anesthesia providers to consider as they plan the perioperative care of their patients. More evidence is needed about the effect of currently used analgesics and other perioperative techniques on CPSP.  相似文献   
36.
37.
38.
A prospective study of the impact of training 41 hospice nurses in assessment skills was used to test hypotheses that blocking behaviours would be used more when patients disclosed feelings and used less when nurses perceived that they had satisfactory professional support Each nurse was asked to assess a patient's current problems before and after feedback training and 8 months later Audiotape recordings of these interviews were rated by trained raters They determined the frequency of nurses' responses which had the function of blocking patient disclosure and the emotional level of patient disclosure Before each patient assessment each nurse was interviewed and questionnaires administered to measure her perceptions of the support she received Blocking behaviours were most evident when patients disclosed their feelings (Kendalls r=0 36, P < 0 001) In interviews containing most patient disclosure of feeling, blocking was significantly less (r= - 0 24, P < 0 5) when the nurse felt that practical help would be available if needed and when the nurse felt that her direct supervisor was concerned about the nurse's own welfare (r= -0 37, P < 0 005)  相似文献   
39.
Gastroparesis in a chronic setting is a disorder that results in diminished quality of life. Laparoscopic gastric electrical stimulator (GES) placement is now being performed in patients with medically refractory gastroparesis. During this procedure, a significant amount of suturing is required to anchor the electrodes to the gastric wall. Robotic surgery may provide surgeons with several technical and ergonomic advantages during this procedure, when compared with a standard laparoscopic approach. The aim of this study is to present a case and review the technique and literature for robotic placement of GES. This report demonstrates the safety and feasibility of robotic GES placement.  相似文献   
40.
Two patients with multifocal idiopathic fibrosclerosis and sclerosing cholangitis developed biliary obstruction due to a fibrotic pancreatic pseudotumor. The masslike fibrosis mimicked pancreatic carcinoma on sonography and cholangiopancreatography. In one patient sonography was successfully used to assess the response of the pseudotumor to corticosteroid therapy.  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