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   10146篇
  免费   482篇
  国内免费   211篇
耳鼻咽喉   6篇
儿科学   238篇
妇产科学   1109篇
基础医学   380篇
口腔科学   4篇
临床医学   1474篇
内科学   770篇
皮肤病学   54篇
神经病学   74篇
特种医学   514篇
外国民族医学   1篇
外科学   2452篇
综合类   1719篇
预防医学   670篇
眼科学   3篇
药学   706篇
  16篇
中国医学   327篇
肿瘤学   322篇
  2024年   22篇
  2023年   146篇
  2022年   318篇
  2021年   373篇
  2020年   302篇
  2019年   327篇
  2018年   304篇
  2017年   266篇
  2016年   331篇
  2015年   307篇
  2014年   838篇
  2013年   769篇
  2012年   678篇
  2011年   806篇
  2010年   610篇
  2009年   613篇
  2008年   591篇
  2007年   529篇
  2006年   464篇
  2005年   374篇
  2004年   309篇
  2003年   248篇
  2002年   176篇
  2001年   159篇
  2000年   116篇
  1999年   130篇
  1998年   81篇
  1997年   82篇
  1996年   76篇
  1995年   56篇
  1994年   43篇
  1993年   38篇
  1992年   33篇
  1991年   47篇
  1990年   23篇
  1989年   33篇
  1988年   23篇
  1987年   19篇
  1986年   16篇
  1985年   36篇
  1984年   19篇
  1983年   12篇
  1982年   17篇
  1981年   12篇
  1980年   15篇
  1979年   12篇
  1978年   13篇
  1977年   6篇
  1976年   10篇
  1975年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A comparison was made of the effects of continuous epidural analgesia with bupivacaine and intermittent epidural morphine on bowel function after abdominal hysterectomy. The duration of postoperative ileus was assessed as the time from the end of operation to the first postoperative passage of flatus and feces. Twenty-two patients were randomly allocated to two equal groups. An "epidural morphine" group received general anesthesia and epidural morphine for postoperative pain relief, and an "epidural bupivacaine" group was given combined general anesthesia and epidural anesthesia with 0.5% bupivacaine intraoperatively and epidural analgesia with 0.25% bupivacaine postoperatively. Epidural morphine or bupivacaine was given for 42 h postoperatively. Pain intensity (visual analog scale) was low in both groups, but lower (P less than 0.05) in the epidural bupivacaine group. The time to first passage of flatus was 22 +/- 16 h in the epidural bupivacaine group and 56 +/- 22 h in the epidural morphine group (P less than 0.001). The time to first postoperative passage of feces was shorter (P less than 0.05) in the former than in the latter 57 +/- 44 h vs 92 +/- 22 h). The patients of the epidural bupivacaine group started intake of oral fluids earlier (P less than 0.01) and to a greater extent (P less than 0.05) than those in the epidural morphine group. It is concluded that the duration of postoperative ileus after hysterectomy is shorter when epidural bupivacaine is given for postoperative pain relief than when this is achieved by epidural morphine.  相似文献   
42.
In a radiologic search for embolized leaflets of Edwards-Duromedics bileaflet valves in 2 patients, the embolized fragments were localized in the iliac vessels using computed tomography. Sonography was successful in one case and standard X-ray films of the abdomen were negative in both cases.In vitro investigations with Björk-Shiley and Edwards-Duromedics leaflets suggested that standard X-ray films of the abdomen and pelvis should be considered as the first investigational technique. If negative, computed tomography of the lower abdomen should be done.  相似文献   
43.
子宫切除术对性生活质量的影响及其干预   总被引:5,自引:2,他引:5  
目的 :了解子宫切除时宫颈去留对术后性生活质量的影响 ,并观察健康教育干预对提高患者术后性生活质量的作用。方法 :将因子宫良性病变而行子宫切除的病人分为全切组和次切组 ,每组再随机分为干预组和非干预组 ,分别进行术后性生活质量评分比较。结果 :1 在未经心理干预的子宫切除病人中次切组性生活质量评分高于全切组 (P <0 0 5 ) ;2 干预组术后性生活质量评分高于非干预组 (P <0 0 5 )。结论 :子宫切除时保留宫颈及手术前后的健康教育干预有利于患者术后性生活质量的改善  相似文献   
44.
目的:探讨人工补片无张力疝修补术的疗效和优点。方法:对59例71个腹外疝在疝囊高位结扎后行人工补片无张力修补术的临床效果进行回顾性分析。结果:本组51例63个腹股沟疝和股疝的手术时间为30—80min,平均55min。术后切口均一期愈合,无切口感染、硬结、异物反应等并发症;术后并发短暂尿潴留2例;阴囊血肿2例、积液4例5侧。腹股沟疝术后5~7天(平均6天)出院,切口疝术后8-11天(平均9天)出院。随访5—51个月,复发2例。结论:人工补片无张力疝修补术是一种简单、安全、痛苦小、恢复快、效果好的疝修补方法,适用于腹壁缺损不严重的各种腹外侧及复发疝。  相似文献   
45.
We hypothesized that walking at increased speed or increasing gradient might have different effects on chest wall kinematics and respiratory muscle power components, and contribute differently to respiratory effort sensation. We measured the volumes of chest wall compartments by optoelectronic plethysmography, esophageal, gastric and transdiaphragmatic (P di) pressures, and the sensation of the respiratory effort by a Borg scale in five normal subjects walking both at ascending gradient with constant speed (AG) and at ascending speed with constant gradient (AS). Chest wall kinematics, evaluated by displacement of chest wall compartments, did not show any significant difference between AS and AG. Muscle power, calculated as the product of mean flow and mean pressure, increased similarly, but its partitioning into pressure and velocity of shortening differed in the two modes. A greater increase in the pressure developed by the abdominal muscles (P abm) (4.06-fold), and in the velocity of shortening of both rib cage inspiratory muscles (v rcm,i) (2.01-fold) and the diaphragm (v di) (1.90-fold) was associated with a lower increase in the pressure developed by the rib cage inspiratory muscles (P rcm,i) (1.24-fold) and P di (0.99-fold) with AG. Instead, with AS, a lower increase in P abm (2.12-fold), v rcm,i (1.66-fold) and v di (1.54-fold) was associated with a greater increase in P rcm,i (1.56-fold) and P di (1.97-fold). A combination of P abm and v di during AG (Wald 2=23.19, P<0.0000), with the addition of P rcm,i during AS (Wald 2=29.46, P<0.0000), was the best predictor of Borg score. In conclusion, the general strategy adopted by respiratory centers during different walking modes does not differ in terms of ventilation, chest wall kinematics, and respiratory muscle power production, whereas it does in terms of partitioning of power into pressure and velocity of shortening, and respiratory muscle contribution to respiratory effort sensation. Combinations of different patterns of flow and pressure generation made the respiratory effort sensation similar during AS and AG modes.  相似文献   
46.
Among cases that had multiple renal arteries on one side, an inferior supernumerary renal artery was found in 24/270 cases (ca. 9%) on the right and in 19/270 cases (ca. 7%) on the left, together with the usual renal artery. We have noticed that there are correlations between their levels of origin from the aorta and their positional relation to the ureter and the inferior vena cava (IVC). An inferior supernumerary renal artery (InfRA) of lower origin passes in front of the IVC and behind the ureter. An InfRA of middle origin passes in front of both the IVC and the ureter. An InfRA of upper origin passes behind the IVC and in front of the ureter or renal pelvis. In addition there was a tendency for the lower origin type to have an ureteric branch, while the middle and upper origin types had a gonadal branch. These findings suggest that different derivations lead to the inferior supernumerary renal arteries.  相似文献   
47.
BACKGROUND: This prospective study was designed to evaluate the operative morbidity and reproductive outcome in patients who had secondary myomectomy for recurrent symptomatic uterine fibroids. METHODS: A total of 58 women were subjected to a secondary myomectomy via the abdominal route. The operative morbidity such as blood loss, presence of adhesions and febrile index were estimated and the pregnancy outcome over a 2-4 year period of follow-up. RESULTS: The mean age and standard deviation (+/- SD) of the women was 35 (+/- 2.4) years. Nineteen patients (33%) had a postoperative temperature vertical line 100 degrees F and the estimated blood loss ranged from 159-2500 ml (median 700 ml). Seven patients (12%) required blood transfusion and one had a hysterectomy due to haemorrhage. Nine women (15.5%) became pregnant but only five (56%) had live births. Those with successful pregnancies tended to be younger with a mean age of 31.8 (+/- 2.6) years versus 35 (+/- 1.8) years, (P = 0.08, non-significant) and had fewer uterine leiomyomata; median with range values, 2 (1-6) versus 7 (6-15). The variables which best predicted the postoperative likelihood of pregnancy were; age, presence of tubal adhesions and the number of uterine fibroids. CONCLUSION: This prospective study showed a high operative morbidity and a poor fertility outcome after a repeat myomectomy. The factors affecting successful outcome in a logistic regression model were age, tubal adhesions and number of uterine fibroids.  相似文献   
48.
The purpose of our study was to review and evaluate retrospectively the experience of an in-vitro fertilization (IVF) surrogate gestational programme in a tertiary care and academic centre. In a 15 year period from 1984 to 1999, a total of 180 cycles of IVF surrogate gestational pregnancy was started in 112 couples. On average, the women were 34.4 +/- 4.4 years of age, had 11.1 +/- 0.72 oocytes obtained per retrieval, 7.1 +/- 0.5 oocytes fertilized and 5. 8 +/- 0.4 embryos subsequently cleaved. Sixteen cycles (8.9%) were cancelled due to poor stimulation. Except for six cycles (3.3%) where there were no embryos available, an average of 3.2 +/- 0.1 embryos was transferred to each individual recipient. The overall pregnancy rate per cycle after IVF surrogacy was 24% (38 of 158), with a clinical pregnancy rate of 19% (30 of 158), and a live birth rate of 15.8% (25 of 158). When compared to patients who underwent a hysterectomy, individuals with congenital absence of the uterus had significantly more oocytes retrieved (P < 0.006), fertilized, cleaved and more embryos available for transfer despite being of comparable age. IVF surrogate gestation is an established, yet still controversial, approach to the care of infertile couples. Take-home baby rates are comparable to conventional IVF over the same 15 year span in our programme. Patients with congenital absence of the uterus responded to ovulation induction better than patients who underwent a hysterectomy, perhaps due in part to ovarian compromise from previous surgical procedures.  相似文献   
49.
Fibroids, infertility and pregnancy wastage   总被引:12,自引:0,他引:12  
Uterine fibroids are often found in women of reproductive age. Different types of fibroids may affect reproductive outcome to a different extent, with submucous, intramural and subserosal fibroids being (in decreasing order of importance) a cause of infertility and pregnancy wastage. Fibroids may also produce a number of complications during pregnancy. Women who are scheduled for assisted conception should be advised to have submucous and possibly intramural fibroids removed prior to IVF. Large fibroids (>5 cm), wherever their location, should be considered individually, with the reproductive history being an important consideration. Miscarriage rates are significantly reduced following myomectomy. Open myomectomy should be the route of choice when there are large subserosal or intramural fibroids, multiple fibroids or entry into the uterine cavity is to be expected. Proper assessment of the benefits and risks of surgery for individual patients should be carefully considered before offering a procedure.  相似文献   
50.
目的探讨腹主动脉瘤腔内修复术(EVAR)后医院感染病原特点及Hippo信号通路基因、白细胞介素-17(Interleukin-17,IL-17)、IL-23改变。方法选择天津医院血管外科2017年5月-2020年3月收治腹主动脉瘤EVAR术后医院感染患者49例作为感染组,选择同期医院进行EVAR术后未发生医院感染患者60例作为非感染组。采用实时荧光定量逆转录聚合酶链反应(RT-PCR)法检测Hippo通路基因yap、taz、mst1相对表达水平,采用酶联免疫吸附法检测其辅助型T细胞17(Th17)促炎细胞因子白细胞介素-17(IL-17)、IL-23水平。结果49例患者共发生肺部感染33例(67.35%),尿路感染10例(20.41%),手术切口感染4例(8.16%),移植物感染2例(4.08%);感染病原以革兰阳性菌为主,共25株,占51.02%,革兰阴性菌共22株,占44.90%,真菌2株,占4.08%;感染组yap、taz、mst1基因相对表达水平和IL-17、IL-23水平高于非感染组(P<0.05)。结论腹主动脉瘤EVAR术后医院感染以肺部感染、尿路感染为主,应及时予以针对性预防;Hippo通路参与了感染发生过程,通过Th17促炎途径诱导炎症反应,其机制仍有待研究。  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